TS4997
2 x 1W differential input stereo audio amplifier with programmable 3D effects
Features
QFN16 4x4mm
Operating range from VCC= 2.7V to 5.5V 1W output power per channel @ VCC=5V, THD+N=1%, RL=8 Ultra low standby consumption: 10nA typ. 80dB PSRR @ 217Hz with grounded inputs High SNR: 106dB(A) typ. Fast startup time: 45ms typ. Pop&click-free circuit Dedicated standby pin per channel Lead-free QFN16 4x4mm package
3D0 3D1 BYP VCC 16 15 14 13
Pin connections (top view)
Applications
Cellular mobile phones Notebook and PDA computers LCD monitors and TVs Portable audio devices
LINLIN+ RIN+ RIN1 2 3 4 12 LOUT11 LOUT+ 10 ROUT+ 9 ROUT-
Description
The TS4997 is designed for top-class stereo audio applications. Thanks to its compact and power-dissipation efficient QFN16 package with exposed pad, it suits a variety of applications. With a BTL configuration, this audio power amplifier is capable of delivering 1W per channel of continuous RMS output power into an 8 load @ 5V. 3D effects enhancement is programmed through a two digital input pin interface that allows more flexibility on each output audio sound channel.
5
6
7
8
GND GND STBYR STBYL
Each output channel (left and right), also has its own external controlled standby mode pin to reduce the supply current to less than 10nA per channel. The device also features an internal thermal shutdown protection. The gain of each channel can be configured by external gain setting resistors.
February 2007
Rev 2
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Contents
TS4997
Contents
1 2 3 4 Typical application schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14 General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Differential configuration principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Gain in typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Common mode feedback loop limitations . . . . . . . . . . . . . . . . . . . . . . . . . 21 Low frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3D effect enhancement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Power dissipation and efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Footprint recommendation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Decoupling of the circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Standby control and wake-up time tWU
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Shutdown time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Pop performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Single-ended input configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Notes on PSRR measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5 6 7
QFN16 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
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TS4997
Typical application schematics
1
Typical application schematics
Figure 1 shows a typical application for the TS4997 with a gain of +6dB set by the input resistors. Figure 1. Typical application schematics
VCC
3D0 Control
3D1 Control
Cs 1 uF
16
15
TS4997 - QFN16
Dif f. input LP1 330nF 2 4k 1 Cin2 P2 2 Dif f. input L+ 330nF 2 4k
LI N+ LI N-
Cin1
Rin1
3D 0 3D 1
13
Vcc
O pt ional
L EFT
LOU T-
12
Left Speaker
Rin2
3D EFF EC T
RI GH T
+ +
LOU T+
11
8 Ohms
Dif f. input RP3
Cin3
Rin3
4
R IN -
R OUT -
9
Right Speaker
330nF
2 4k 3
R IN +
R OUT +
10
8 Ohms
Cin4 P4
Rin4
Bypa ss
Dif f. input R+
330nF
2 4k 14 BIA S
STBYL
S TBY
STBYR
GN D
GN D
5
6
8
1uF Cb
S TB YL Control
Table 1.
External component descriptions
Functional description Input resistors that set the closed loop gain in conjunction with a fixed internal feedback resistor (Gain = Rfeed/RIN, where Rfeed = 50k). Input coupling capacitors that block the DC voltage at the amplifier input terminal. Thanks to common mode feedback, these input capacitors are optional. However, if they are added, they form with RIN a 1st order high pass filter with -3dB cut-off frequency (fcut-off = 1 / (2 x x RIN x CIN)). Supply bypass capacitors that provides power supply filtering. Bypass pin capacitor that provides half supply filtering.
Components RIN
CIN
CS CB
STB YR Control
7
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Absolute maximum ratings
T S4997
2
Absolute maximum ratings
Table 2.
Symbol VCC Vi Toper Tstg Tj Rthja Pd ESD ESD Supply voltage (1) Input voltage
(2)
Absolute maximum ratings
Parameter Value 6 GND to VCC -40 to + 85 -65 to +150 150 120 Internally limited 2 1.5 200 200 kV V mA Unit V V C C C C/W
Operating free air temperature range Storage temperature Maximum junction temperature Thermal resistance junction to ambient Power dissipation Human body model (3) Digital pins STBYL, STBYR, 3D0, 3D1 Machine model Latch-up immunity
1. All voltage values are measured with respect to the ground pin. 2. The magnitude of the input signal must never exceed VCC + 0.3V / GND - 0.3V. 3. All voltage values are measured from each pin with respect to supplies.
Table 3.
Symbol VCC VICM VIL VIH VSTBY RL
Operating conditions
Parameter Supply voltage Common mode input voltage range 3D0 - 3D1 maximum low input voltage 3D0 - 3D1 minimum high input voltage Standby voltage input: Device ON Device OFF Load resistor Value 2.7 to 5.5 GND to VCC - 1V 0.4 1.3 1.3 VSTBY VCC GND VSTBY 0.4 4 1 150 45 85 Unit V V V V V M C C/W
ROUT/GND Output resistor to GND (VSTBY = GND) TSD Rthja
1. 2.
Thermal shutdown temperature Thermal resistance junction to ambient QFN16(1) QFN16(2)
When mounted on a 4-layer PCB with vias. When mounted on a 2-layer PCB with vias.
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TS4997
Electrical characteristics
3
Table 4.
Symbol IC C ISTBY Voo Po THD + N
Electrical characteristics
VCC = +5V, GND = 0V, Tamb = 25C (unless otherwise specified)
Parameter Supply current No input signal, no load, left and right channel active Standby current (1) No input signal, VSTBYL = GND, VSTBYR = GND, RL = 8 Output offset voltage No input signal, RL = 8 Output power THD = 1% Max, F = 1kHz, RL = 8 Total harmonic distortion + noise Po = 700mWrms, G = 6dB, RL = 8, 20Hz F 20kHz Power supply rejection ratio(2), inputs grounded RL = 8, G = 6dB, Cb = 1F, Vripple = 200mVpp, 3D effect off F = 217Hz F = 1kHz Common mode rejection ratio(3) RL = 8, G = 6dB, Cb = 1F, Vincm = 200mVpp, 3D effect off F = 217Hz F = 1kHz SNR Signal-to-noise ratio A-weighted, G = 6dB, Cb = 1F, RL = 8, 3D effect off (THD + N 0.5%, 20Hz < F < 20kHz) , Channel separation, RL = 8 G = 6dB, 3D effect off F = 1kHz F = 20Hz to 20kHz Output voltage noise, F = 20Hz to 20kHz, RL = 8, G=6dB Cb = 1F, 3D effect off Unweighted A-weighted Gain value (RIN in k) Wake-up time (Cb = 1F) Standby time (Cb = 1F) Phase margin at unity gain , RL = 8 CL = 500pF , Gain margin, RL = 8 CL = 500pF Gain bandwidth product, RL = 8 4---------- 0 k ---RI N
Min.
Typ. 7.4 10 1
Max. 9.6 2000 35
Unit mA nA mV mW %
800
1000 0.5
PSRR
80 75
dB
CMRR
57 57
dB
108
dB
Crosstalk
105 80
dB
VN
15 10 5---------- 0 k ---RI N
Vrms 6---------- 0 k ---RI N
Gain tWU tSTBY M GM GBP
V/V ms s Degrees dB MHz
46 10 65 15 1.5
1. Standby mode is active when VSTBY is tied to GND. 2. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the sinusoidal signal superimposed upon VCC. 3. Dynamic measurements - 20*log(rms(Vout)/rms(Vincm)).
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Electrical characteristics
TS4997
Table 5.
Symbol IC C ISTBY Voo Po THD + N
VCC = +3.3V, GND = 0V, Tamb = 25C (unless otherwise specified)
Parameter Supply current No input signal, no load, left and right channel active Standby current (1) No input signal, VSTBYL = GND, VSTBYR = GND, RL = 8 Output offset voltage No input signal, RL = 8 Output power THD = 1% Max, F = 1kHz, RL = 8 Total harmonic distortion + noise Po = 300mWrms, G = 6dB, RL = 8, 20Hz F 20kHz Power supply rejection ratio(2), inputs grounded RL = 8, G = 6dB, Cb = 1F, Vripple = 200mVpp, 3D effect off F = 217Hz F = 1kHz Common mode rejection ratio(3) RL = 8, G = 6dB, Cb = 1F, Vincm = 200mVpp, 3D effect off F = 217Hz F = 1kHz 57 57 370 Min. Typ. 6.6 10 1 460 0.5 Max. 8.6 2000 35 Unit mA nA mV mW %
PSRR
80 75
dB
CMRR
dB
SNR
Signal-to-noise ratio A-weighted, G = 6dB, Cb = 1F, RL = 8, 3D effect off (THD + N 0.5%, 20Hz < F < 20kHz) , Channel separation, RL = 8 G = 6dB, 3D effect off F = 1kHz F = 20Hz to 20kHz Output voltage noise, F = 20Hz to 20kHz, RL = 8, G=6dB Cb = 1F, 3D effect off Unweighted A-weighted Gain value (RIN in k) Wake-up time (Cb = 1F) Standby time (Cb = 1F) Phase margin at unity gain , RL = 8 CL = 500pF Gain margin , RL = 8 CL = 500pF Gain bandwidth product RL = 8 4---------- 0 k ---RI N
104
dB
Crosstalk
105 80
dB
VN
15 10 5---------- 0 k ---RI N
Vrms 6---------- 0 k ---RI N
Gain tWU tSTBY M GM GBP
V/V ms s Degrees dB MHz
47 10 65 15 1.5
1. Standby mode is active when VSTBY is tied to GND. 2. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the sinusoidal signal superimposed upon VCC. 3. Dynamic measurements - 20*log(rms(Vout)/rms(Vincm)).
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TS4997
Electrical characteristics
Table 6.
Symbol IC C ISTBY Voo Po THD + N
VCC = +2.7V, GND = 0V, Tamb = 25C (unless otherwise specified)
Parameter Supply current No input signal, no load, left and right channel active Standby current (1) No input signal, VSTBYL = GND, VSTBYR = GND, RL = 8 Output offset voltage No input signal, RL = 8 Output power THD = 1% Max, F = 1kHz, RL = 8 Total harmonic distortion + noise Po = 200mWrms, G = 6dB, RL = 8, 20Hz F 20kHz Power supply rejection ratio(2), inputs grounded RL = 8, G = 6dB, Cb = 1F, Vripple = 200mVpp, 3D effect off F = 217Hz F = 1kHz Common mode rejection ratio(3) RL = 8, G = 6dB, Cb = 1F, Vincm = 200mVpp, 3D effect off F = 217Hz F = 1kHz 57 57 220 Min. Typ. 6.2 10 1 295 0.5 Max. 8.1 2000 35 Unit mA nA mV mW %
PSRR
76 73
dB
CMRR
dB
SNR
Signal-to-noise ratio A-weighted, G = 6dB, Cb = 1F, RL = 8, 3D effect off (THD + N 0.5%, 20Hz < F < 20kHz) , Channel separation, RL = 8 G = 6dB, 3D effect off F = 1kHz F = 20Hz to 20kHz Output voltage noise, F = 20Hz to 20kHz, RL = 8, G=6dB Cb = 1F, 3D effect off Unweighted A-weighted Gain value (RIN in k) Wake-up time (Cb = 1F) Standby time (Cb = 1F) Phase margin at unity gain , RL = 8 CL = 500pF Gain margin , RL = 8 CL = 500pF Gain bandwidth product RL = 8 4---------- 0 k ---RI N
102
dB
Crosstalk
105 80
dB
VN
15 10 5---------- 0 k ---RI N
Vrms 6---------- 0 k ---RI N
Gain tWU tSTBY M GM GBP
V/V ms s Degrees dB MHz
46 10 65 15 1.5
1. Standby mode is active when VSTBY is tied to GND. 2. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the sinusoidal signal superimposed upon VCC. 3. Dynamic measurements - 20*log(rms(Vout)/rms(Vincm)).
7/34
Electrical characteristics Table 7. Index of graphics
Description THD+N vs. output power THD+N vs. frequency PSRR vs. frequency PSRR vs. common mode input voltage CMRR vs. frequency CMRR vs. common mode input voltage Crosstalk vs. frequency SNR vs. power supply voltage Differential DC output voltage vs. common mode input voltage Current consumption vs. power supply voltage Current consumption vs. standby voltage Standby current vs. power supply voltage Frequency response Output power vs. load resistance Output power vs. power supply voltage Power dissipation vs. output power Power derating curves Figure Figure 2 to 13 Figure 14 to 19 Figure 20 to 28 Figure 29 Figure 30 to 35 Figure 36 Figure 37 to 39 Figure 40 to 45 Figure 46 to 48 Figure 49 Figure 50 to 52 Figure 53 Figure 54 to 56 Figure 57 Figure 58 to 59 Figure 60 to 62 Figure 63
TS4997
Page page 9 to page 10 page 11 page 12 to page 13 page 13 page 13 to page 14 page 14 page 14 to page 15 page 15 to page 16 page 16 page 16 page 17 page 17 page 17 to page 18 page 18 page 18 page 18 to page 19 page 19
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TS4997
Electrical characteristics
Figure 2.
10
THD+N vs. output power
Figure 3.
10
THD+N vs. output power
V c c = 2 .7 V
THD + N (%)
THD + N (%)
R L = 4 G = +6dB F = 1kHz C b = 1F 1 B W < 125kHz T a m b = 25C
V cc =5 V
V c c = 3 .3 V
R L = 4 G = +12dB F = 1kHz C b = 1F 1 B W < 125kHz T a m b = 25C
Vcc=5V
V c c = 3 .3 V V c c = 2 .7 V
0 .1
0 .1
0 .0 1 1 E -3
0 .0 1
0 .1
O u tp u t power (W)
1
0 .0 1 1 E -3
0 .0 1
0 .1
O u tp u t power (W)
1
Figure 4.
10
THD+N vs. output power
Figure 5.
10
THD+N vs. output power
V c c = 2 .7 V 0 .1
THD + N (%)
THD + N (%)
R L = 8 G = +6dB F = 1kHz C b = 1F 1 B W < 125kHz T a m b = 25C
V c c=5 V
V c c = 3 .3 V
R L = 8 G = +12dB F = 1kHz C b = 1F 1 B W < 125kHz T a m b = 25C
Vcc=5V
V c c = 3 .3 V
V c c = 2 .7 V 0 .1
0 .0 1 1 E -3
0 .0 1
0 .1
O u tp u t power (W)
1
0 .0 1 1 E -3
0 .0 1
0 .1
O u tp u t power (W)
1
Figure 6.
10
THD+N vs. output power
Figure 7.
10
THD+N vs. output power
THD + N (%)
V c c = 2 .7 V 0 .1
THD + N (%)
R L = 16 G = +6dB F = 1kHz C b = 1F 1 B W < 125kHz T a m b = 25C
V c c=5 V
V c c = 3 .3 V
R L = 16 G = +12dB F = 1kHz C b = 1F 1 B W < 125kHz T a m b = 25C
Vcc=5V
V c c = 3 .3 V
V c c = 2 .7 V 0 .1
0 .0 1 1 E -3
0 .0 1
0 .1
1
0 .0 1 1 E -3
0 .0 1
0 .1
1
O u tp u t power (W)
O u tp u t power (W)
9/34
Electrical characteristics
TS4997
Figure 8.
10
THD+N vs. output power
Figure 9.
10
THD+N vs. output power
THD + N (%)
V c c = 2 .7 V
THD + N (%)
R L = 4 G = +6dB F = 10kHz C b = 1F 1 B W < 125kHz T a m b = 25C
V cc =5 V
V c c = 3 .3 V
R L = 4 G = +12dB F = 10kHz C b = 1F 1 B W < 125kHz T a m b = 25C
Vcc=5V
V c c = 3 .3 V V c c = 2 .7 V
0 .1
0 .1
0 .0 1 1 E -3
0 .0 1
0 .1
O u tp u t power (W)
1
0 .0 1 1 E -3
0 .0 1
0 .1
O u tp u t power (W)
1
Figure 10. THD+N vs. output power
10 R L = 8 G = +6dB F = 10kHz C b = 1F 1 B W < 125kHz T a m b = 25C Vcc=5V
Figure 11. THD+N vs. output power
10 R L = 8 G = +12dB F = 10kHz C b = 1F 1 B W < 125kHz T a m b = 25C Vcc=5V
V c c = 3 .3 V
THD + N (%)
THD + N (%)
V c c = 3 .3 V
V c c = 2 .7 V 0 .1
V c c = 2 .7 V 0 .1
0 .0 1 1 E -3
0 .0 1
0 .1
O u tp u t power (W)
1
0 .0 1 1 E -3
0 .0 1
0 .1
O u tp u t power (W)
1
Figure 12. THD+N vs. output power
10 R L = 16 G = +6dB F = 10kHz C b = 1F 1 B W < 125kHz T a m b = 25C Vcc=5V
Figure 13. THD+N vs. output power
10 R L = 16 G = +12dB F = 10kHz C b = 1F 1 B W < 125kHz T a m b = 25C Vcc=5V
THD + N (%)
THD + N (%)
V c c = 3 .3 V
V c c = 3 .3 V
V c c = 2 .7 V 0 .1
V c c = 2 .7 V 0 .1
0 .0 1 1 E -3
0 .0 1
0 .1
1
0 .0 1 1 E -3
0 .0 1
0 .1
1
O u tp u t power (W)
O u tp u t power (W)
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TS4997
Electrical characteristics
Figure 14. THD+N vs. frequency
10 R L = 4 G = +6dB C b = 1F B W < 125kHz T a m b = 25C
Figure 15. THD+N vs. frequency
10 R L = 4 G = +12dB C b = 1F B W < 125kHz Ta m b = 25C
V c c=5 V P o u t= 9 5 0 m W 1
THD + N (%)
Vcc=5V P o u t= 9 5 0 m W V c c = 3 .3 V P o u t= 4 3 0 m W
1
THD + N (%)
V c c = 3 .3 V P o u t= 4 3 0 m W
0 .1
0 .1 V c c = 2 .7 V P o u t= 2 6 0 m W
V c c = 2 .7 V P o u t= 2 6 0 m W 0 .0 1 100 1000
F r eq u e n c y (Hz)
10000
0 .0 1
100
1000
F re q u en c y (Hz)
10000
Figure 16. THD+N vs. frequency
10 R L = 8 G = +6dB C b = 1F B W < 125kHz 1 T a m b = 25C
Figure 17. THD+N vs. frequency
10 R L = 8 G = +12dB C b = 1F B W < 125kHz Ta m b = 25C
Vcc=5V P o u t= 7 0 0 m W 1
THD + N (%)
V cc =5 V P o u t= 7 0 0 m W V c c = 3 .3 V P o u t= 3 0 0 m W V c c = 2 .7 V P o u t= 2 0 0 m W
THD + N (%)
V c c = 3 .3 V P o u t= 3 0 0 m W V c c = 2 .7 V P o u t= 2 0 0 m W
0 .1
0 .1
0 .0 1
100
1000
F r eq u e n c y (Hz)
10000
0 .0 1
100
1000
F re q u en c y (Hz)
10000
Figure 18. THD+N vs. frequency
10 R L = 16 G = +6dB C b = 1F B W < 125kHz 1 T a m b = 25C
Figure 19. THD+N vs. frequency
10 R L = 16 G = +12dB C b = 1F B W < 125kHz 1 Ta m b = 25C
Vcc=5V P o u t= 4 5 0 m W
THD + N (%)
Vcc=5V P o u t= 4 5 0 m W V c c = 3 .3 V P o u t= 2 0 0 m W V c c = 2 .7 V P o u t= 1 2 0 m W
THD + N (%)
V c c = 3 .3 V P o u t= 2 0 0 m W V c c = 2 .7 V P o u t= 1 2 0 m W
0 .1
0 .1
0 .0 1
100
1000
F r eq u e n c y (Hz)
10000
0 .0 1
100
1000
F re q u en c y (Hz)
10000
11/34
Electrical characteristics
TS4997
Figure 20. PSRR vs. frequency
0 -1 0 -2 0 -3 0
PSRR (dB)
Figure 21. PSRR vs. frequency
0 V c c = 5V V rip p le = 200mVpp G = +12dB C b = 1F, Cin = 4.7F In p u ts Grounded Ta m b = 25C 3 D MEDIUM -5 0 -6 0 -7 0 -8 0 3 D OFF 3 D LOW
3 D MEDIUM 3 D LOW
-5 0 -6 0 -7 0 -8 0 -9 0 -1 0 0 100 1000
F re q u e n cy (Hz)
PSRR (dB)
-4 0
V c c = 5V V rip p le = 200mVpp G = +6dB C b = 1F, Cin = 4.7F In p u ts Grounded Ta m b = 25C
-1 0 -2 0 3 D HIGH -3 0 -4 0
3 D HIGH
3 D OFF 10000
-9 0 -1 0 0 100 1000
10000
F re q u e n cy (Hz)
Figure 22. PSRR vs. frequency
0 -1 0 -2 0 -3 0
PSRR (dB)
Figure 23. PSRR vs. frequency
0 V c c = 3.3V V rip p le = 200mVpp G = +6dB C b = 1F, Cin = 4.7F In p u ts Grounded Ta m b = 25C 3 D MEDIUM -5 0 -6 0 -7 0 -8 0 -9 0 3 D OFF 3 D OFF 100 1000
F re q u e n cy (Hz)
V c c = 5V V rip p le = 200mVpp C b = 1F In p u ts Floating T a m b = 25C 3 D MEDIUM
-1 0 -2 0 3 D HIGH
PSRR (dB)
-3 0 -4 0
3 D HIGH
-4 0 -5 0 -6 0 -7 0 -8 0 -9 0 -1 0 0 100 1000
F re q u e n cy (Hz)
3 D LOW
3 D LOW
10000
-1 0 0
10000
Figure 24. PSRR vs. frequency
0 -1 0 -2 0 -3 0
PSRR (dB)
Figure 25. PSRR vs. frequency
0 V c c = 3.3V V rip p le = 200mVpp C b = 1F In p u ts Floating T a m b = 25C 3 D MEDIUM -5 0 -6 0 -7 0 -8 0 3 D OFF -9 0 10000 -1 0 0 3 D OFF 100 1000
F re q u e n cy (Hz)
3 D MEDIUM 3 D LOW
-5 0 -6 0 -7 0 -8 0 -9 0 -1 0 0 100 1000
F re q u e n cy (Hz)
PSRR (dB)
-4 0
V c c = 3.3V V rip p le = 200mVpp G = +12dB C b = 1F, Cin = 4.7F In p u ts Grounded Ta m b = 25C
-1 0 -2 0 3 D HIGH -3 0 -4 0
3 D HIGH
3 D LOW
10000
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TS4997
Electrical characteristics
Figure 26. PSRR vs. frequency
0 -1 0 -2 0 -3 0
PSRR (dB)
Figure 27. PSRR vs. frequency
0 V c c = 2.7V V rip p le = 200mVpp G = +12dB C b = 1F, Cin = 4.7F In p u ts Grounded Ta m b = 25C 3 D MEDIUM 3 D LOW
3 D MEDIUM 3 D LOW
-5 0 -6 0 -7 0 -8 0 -9 0 -1 0 0 100 1000
F re q u e n cy (Hz)
PSRR (dB)
-4 0
V c c = 2.7V V rip p le = 200mVpp G = +6dB C b = 1F, Cin = 4.7F In p u ts Grounded Ta m b = 25C
-1 0 -2 0 3 D HIGH -3 0 -4 0 -5 0 -6 0 -7 0 -8 0 3 D OFF 10000 -9 0 -1 0 0
3 D HIGH
3 D OFF 100 1000
F re q u e n cy (Hz)
10000
Figure 28. PSRR vs. frequency
Figure 29. PSRR vs. common mode input voltage
0 V rip p le = 200mVpp F = 217Hz, G = +6dB C b = 1F, RL 8 3 D Effect OFF T a m b = 25C
0 -1 0 -2 0 -3 0
PSRR (dB)
V c c = 2.7V V rip p le = 200mVpp C b = 1F In p u ts Floating T a m b = 25C 3 D MEDIUM
-1 0 -2 0
3 D HIGH
PSRR (dB)
-3 0 -4 0 -5 0 -6 0 -7 0 -8 0
-4 0 -5 0 -6 0 -7 0 -8 0 -9 0 -1 0 0 3 D OFF 100 1000
F re q u e n cy (Hz)
3 D LOW
V c c = 2 .7 V
V c c = 3 .3 V
Vcc=5V
10000
-9 0
0
1
2
3
4
5
C o m m o n Mode Input Voltage (V)
Figure 30. CMRR vs. frequency
0 -1 0 -2 0
CMRR (dB)
Figure 31. CMRR vs. frequency
0 V c c = 5V R L 8 G = +12dB V ic = 200mVpp C b = 1F, Cin = 4.7F T a m b = 25C 3 D LOW -4 0 -5 0 -6 0 3 D OFF -7 0 3 D OFF 100 1000
F re q u en c y (Hz)
-3 0 -4 0 -5 0 -6 0 -7 0
CMRR (dB)
V c c = 5V R L 8 G = +6dB V ic = 200mVpp C b = 1F, Cin = 4.7F T a m b = 25C 3 D LOW 3 D MEDIUM
-1 0 -2 0 3 D HIGH -3 0
3 D HIGH
3 D MEDIUM
100
1000
F req u e n c y (Hz)
10000
10000
13/34
Electrical characteristics
TS4997
Figure 32. CMRR vs. frequency
0 -1 0 -2 0
CMRR (dB)
Figure 33. CMRR vs. frequency
0 V c c = 3.3V R L 8 G = +12dB V ic = 200mVpp C b = 1F, Cin = 4.7F T a m b = 25C 3 D LOW -4 0 -5 0 -6 0 3 D OFF -7 0 3 D OFF 100 1000
F re q u en c y (Hz)
-3 0 -4 0 -5 0 -6 0 -7 0
3 D HIGH
CMRR (dB)
V c c = 3.3V R L 8 G = +6dB V ic = 200mVpp C b = 1F, Cin = 4.7F T a m b = 25C 3 D LOW 3 D MEDIUM
-1 0 -2 0 -3 0
3 D HIGH
3 D MEDIUM
100
1000
F req u e n c y (Hz)
10000
10000
Figure 34. CMRR vs. frequency
0 -1 0 -2 0
CMRR (dB)
Figure 35. CMRR vs. frequency
0 V c c = 2.7V R L 8 G = +12dB V ic = 200mVpp C b = 1F, Cin = 4.7F T a m b = 25C 3 D LOW -4 0 -5 0 -6 0 3 D OFF -7 0 3 D OFF 100 1000
F re q u en c y (Hz)
CMRR (dB)
-3 0 -4 0 -5 0 -6 0 -7 0
V c c = 2.7V R L 8 G = +6dB V ic = 200mVpp C b = 1F, Cin = 4.7F T a m b = 25C 3 D LOW 3 D MEDIUM
-1 0 -2 0 3 D H IG H -3 0
3 D HIGH
3 D MEDIUM
100
1000
F req u e n c y (Hz)
10000
10000
Figure 36. CMRR vs. common mode input voltage
20 10 0 -1 0
CMRR (dB)
Figure 37. Crosstalk vs. frequency
0
Crosstalk Level (dB)
V rip p le = 200mVpp F = 217Hz, G = +6dB C b = 1F, RL 8 3 D Effect OFF T a m b = 25C
-1 0 -2 0 -3 0 -4 0 -5 0 -6 0 -7 0 -8 0 -9 0 -1 0 0 -1 1 0 -1 2 0
4 5
R L = 4 G = +6dB C in = 1F, Cb = 1F 3 D Effect OFF T a m b = 25C
-2 0 -3 0 -4 0 -5 0 -6 0 -7 0 -8 0
0 1 2
V c c = 2 .7 V
V c c = 3 .3 V
Vcc=5V V c c = 3 .3 V V c c = 2 .7 V
V cc =5 V
3
100
1000
F r eq u e n c y (Hz)
10000
C o m m o n Mode Input Voltage (V)
14/34
TS4997
Electrical characteristics
Figure 38. Crosstalk vs. frequency
0 -1 0 -2 0
Crosstalk Level (dB)
Figure 39. Crosstalk vs. frequency
0 R L = 16 G = +6dB C in = 1F, Cb = 1F 3 D Effect OFF T a m b = 25C Vcc=5V V c c = 3 .3 V V c c = 2 .7 V
-4 0 -5 0 -6 0 -7 0 -8 0 -9 0 -1 0 0 -1 1 0 -1 2 0
Crosstalk Level (dB)
-3 0
R L = 8 G = +6dB C in = 1F, Cb = 1F 3 D Effect OFF Ta m b = 25C Vcc=5V V c c = 3 .3 V V c c = 2 .7 V
-1 0 -2 0 -3 0 -4 0 -5 0 -6 0 -7 0 -8 0 -9 0 -1 0 0 -1 1 0 -1 2 0
100
1000
F r eq u e n c y (Hz)
10000
100
1000
F r eq u e n c y (Hz)
10000
Figure 40. SNR vs. power supply voltage
110 108 3 D OFF 106 104 102 100 3 D LOW 98 96 94 92 90 88 8 6 3 D HIGH 84 82 80 2 .5 3 .0
Figure 41. SNR vs. power supply voltage
110 108 3 D OFF 106 104 102 3 D LOW 100 98 96 94 92 3 D MIDDLE 90 3 D HIGH 88 86 84 82 80 2 .5 3 .0 3 .5 4 .0
Singnal to Noise Ratio (dB)
3 D MEDIUM
A - Weighted filter F = 1kHz G = +6dB, RL = 4 T H D + N < 0.5% T a m b = 25C 3 .5 4 .0 4 .5 5 .0 5 .5
Singnal to Noise Ratio (dB)
A - weighted filter F = 1kHz G = +6dB ,RL = 8 T H D + N < 0.5% T a m b = 25C 4 .5 5 .0 5 .5
S u p p ly Voltage (V)
S u p p ly Voltage (V)
Figure 42. SNR vs. power supply voltage
110 108 3 D OFF 106 104 102 3 D LOW 100 98 96 94 92 3 D MIDDLE 90 3 D HIGH 88 86 84 82 80 2 .5 3 .0 3 .5 4 .0
Figure 43. SNR vs. power supply voltage
110 108 106 3 D OFF 104 102 100 98 3 D LOW 96 94 92 90 88 86 84 3 D HIGH 82 80 78 76 2 .5 3 .0
Singnal to Noise Ratio (dB)
Singnal to Noise Ratio (dB)
3 D MEDIUM
A - Weighted filter F = 1kHz G = +6dB ,RL = 16 T H D + N < 0.5% T a m b = 25C 4 .5 5 .0 5 .5
U n w e ig h te d filter (20Hz to 20kHz) F = 1kHz G = +6dB, RL = 4 T H D + N < 0.5% T a m b = 25C 3 .5 4 .0 4 .5 5 .0 5 .5
S u p p ly Voltage (V)
S u p p ly Voltage (V)
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Electrical characteristics
TS4997
Figure 44. SNR vs. power supply voltage
110 108 3 D OFF 106 104 102 100 3 D LOW 98 96 94 92 90 88 8 6 3 D HIGH 84 82 80 2 .5 3 .0
Figure 45. SNR vs. power supply voltage
110 108 3 D OFF 106 104 102 100 3 D LOW 98 96 94 92 90 88 3 D HIGH 86 84 82 80 2 .5 3 .0
Singnal to Noise Ratio (dB)
Singnal to Noise Ratio (dB)
3 D MEDIUM
3 D MEDIUM
U n w e ig h te d filter (20Hz to 20kHz) F = 1kHz G = +6dB, RL = 8 T H D + N < 0.5% T a m b = 25C 3 .5 4 .0 4 .5 5 .0 5 .5
U n w e ig h te d filter (20Hz to 20kHz) F = 1kHz G = +6dB, RL = 16 T H D + N < 0.5% T a m b = 25C 3 .5 4 .0 4 .5 5 .0 5 .5
S u p p ly Voltage (V)
S u p p ly Voltage (V)
Figure 46. Differential DC output voltage vs. common mode input voltage
1 0 0 0 V c c = 5V G = +6dB T a m b = 25C 100 3 D MEDIUM 10
|Voo| (mV)
Figure 47. Differential DC output voltage vs. common mode input voltage
1 0 0 0 V c c = 3.3V G = +6dB Ta m b = 25C 100 3 D MEDIUM 10
|Voo| (mV)
3 D HIGH
3 D LOW
3 D HIGH 3 D LOW
1 0 .1 0 .0 1 1 E -3
1 0 .1 0 .0 1 1 E -3 0 .0
3 D OFF
3 D OFF
0
1
2
3
4
5
0 .5
1 .0
1 .5
2 .0
2 .5
3 .0
C o m m o n Mode Input Voltage (V)
C o m m o n Mode Input Voltage (V)
Figure 48. Differential DC output voltage vs. common mode input voltage
1 0 0 0 V c c = 2.7V G = +6dB Ta m b = 25C 100 10
|Voo| (mV)
Figure 49. Current consumption vs. power supply voltage
8 7
Current Consumption (mA)
N o load T a m b = 25C
6 5 4 3 2 1 O n e channel active B o th channels active
3 D HIGH
3 D MEDIUM 3 D LOW
1 0 .1 3 D OFF 0 .0 1 1 E -3 0 .0
0 .5
1 .0
1 .5
2 .0
2 .5
0
0
1
2
3
4
5
C o m m o n Mode Input Voltage (V)
P o w e r Supply Voltage (V)
16/34
TS4997
Electrical characteristics
Figure 50. Current consumption vs. standby voltage
8 7
Current Consumption (mA)
Figure 51. Current consumption vs. standby voltage
7 6
6 5 4 3 2 1 0 0 1 2
B o th channels active
Current Consumption (mA)
5 4 3
B o th channels active
O n e channel active
O n e channel active 2 1 0 0 .0 V c c = 3.3V N o load Ta m b = 25C 0 .5 1 .0 1 .5 2 .0 2 .5 3 .0
V c c = 5V N o load Ta m b = 25C 3 4 5
S tan d b y Voltage (V)
S tan d b y Voltage (V)
Figure 52. Current consumption vs. standby voltage
7 6
Current Consumption (mA)
Figure 53. Standby current vs. power supply voltage
1 .0 N o load 0 .9 T a m b = 25C 0 .8
B o th channels active 4 3 O n e channel active 2 1 0 0 .0 V c c = 2.7V N o load T a m b = 25C 0 .5 1 .0 1 .5 2 .0 2 .5
Standby Current (nA)
5
0 .7 0 .6 0 .5 0 .4 0 .3 0 .2 0 .1 0 .0 0 1 2 3 4 5
S ta n d b y Voltage (V)
P o w e r Supply Voltage (V)
Figure 54. Frequency response
14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 C in = 4 .7 F , Rin=12k
Figure 55. Frequency response
14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 C in = 4 .7 F , Rin=12k
C in = 6 8 0 n F, Rin=12k C in = 4 .7 F , Rin=24k V c c = 5V P o = 700mW 3 D Effect OFF Z L = 8 + 500pF T a m b = 25C 10000 20k
Gain (dB)
C in = 6 8 0 n F, Rin=12k C in = 4 .7 F , Rin=24k V c c = 3.3V P o = 300mW 3 D Effect OFF Z L = 8 + 500pF T a m b = 25C 10000 20k
Gain (dB)
C in = 3 3 0 n F , Rin=24k
C in = 3 3 0 n F , Rin=24k
20
100
1000
F req u e n c y (Hz)
20
100
1000
F req u e n c y (Hz)
17/34
Electrical characteristics
TS4997
Figure 56. Frequency response
14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 C in = 4 .7 F , Rin=12k
Figure 57. Output power vs. load resistance
1800 1600 1400
Output power (mW)
V c c = 5 .5 V V c c=5 V V c c = 4 .5 V Vcc=4V V c c = 3 .3 V
C in = 6 8 0 n F, Rin=12k C in = 4 .7 F , Rin=24k V c c = 2.7V P o = 200mW 3 D Effect OFF Z L = 8 + 500pF T a m b = 25C 10000 20k
1200 1000 800
T H D + N = 1% F = 1kHz C b = 1F B W < 125kHz T a m b = 25C
Gain (dB)
Vcc=3V 600 400 200 0 4 V c c = 2 .7 V 8 12 16 20 24 28 32
C in = 3 3 0 n F , Rin=24k
20
100
1000
F req u e n c y (Hz)
L o a d Resistance ()
Figure 58. Output power vs. power supply voltage
1800 F = 1kHz C b = 1F B W < 125 kHz T a m b = 25C
Figure 59. Output power vs. power supply voltage
2200
Output power at 10% THD + N (mW)
Output power at 1% THD + N (mW)
1600 1400 1200 1000 800 600 400 200
2000 1800 1600 1400 1200 1000 800 600 400 200
RL=4
F = 1kHz C b = 1F B W < 125 kHz T a m b = 25C
RL=4
RL=8 RL=16 RL=32 3 .0 3 .5 4 .0
Vcc (V)
RL=8 RL=16 RL=32 3 .0 3 .5 4 .0
Vcc (V)
0 2 .5
4 .5
5 .0
5 .5
0 2 .5
4 .5
5 .0
5 .5
Figure 60. Power dissipation vs. output power Figure 61. Power dissipation vs. output power
1500 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 600 550 500 RL=4 RL=8
Power Dissipation (mW)
Power Dissipation (mW)
450 400 350 300 250 200 150 100 50 0 0 100 200 300 400 RL=16 RL=8
RL=4
RL=16 V c c = 5V F = 1kHz T H D + N < 1% 0 200 400 600 800 1000 1200 1400 1600
V c c = 3.3V F = 1kHz TH D + N < 1% 500 600 700
O u tp u t Power (mW)
O u tp u t Power (mW)
18/34
TS4997
Electrical characteristics
Figure 62. Power dissipation vs. output power Figure 63. Power derating curves
400
QFN16 Package Power Dissipation (W)
350
Power Dissipation (mW)
300 250 200 150 RL=16 100 50 0 0 50 100 150 200 250 300 RL=8
RL=4
V c c = 2.7V F = 1kHz T H D + N < 1% 350 400 450
3 .0 2 .8 2 .6 2 .4 2 .2 2 .0 1 .8 1 .6 1 .4 1 .2 1 .0 0 .8 0 .6 0 .4 0 .2 0 .0
M o u n te d on 4-layer PCB w ith vias M o u n te d on 2-layer PCB w ith vias
N o Heat sink -AMR value 0 25 50 75 100 125 150
O u tp u t Power (mW)
A m b ia n t Temperature (C)
Table 8.
Output noise, Tamb = 25C
Unweighted filter 3D effect level (20Hz to 20kHz) VCC = 2.7V to 5.5V A-weighted filter VCC = 2.7V to 5.5V 6Vrms 12Vrms 15Vrms 22Vrms 10Vrms 19Vrms 24Vrms 35Vrms 14Vrms 26Vrms 33Vrms 48Vrms
Conditions
Inputs floating Inputs floating Inputs floating Inputs floating Inputs grounded, G=6dB Inputs grounded, G=6dB Inputs grounded, G=6dB Inputs grounded, G=6dB Inputs grounded, G=12dB Inputs grounded, G=12dB Inputs grounded, G=12dB Inputs grounded, G=12dB
OFF LOW MEDIUM HIGH OFF LOW MEDIUM HIGH OFF LOW MEDIUM HIGH
10Vrms 18Vrms 24Vrms 34Vrms 15Vrms 28Vrms 36Vrms 52Vrms 20Vrms 39Vrms 50Vrms 71Vrms
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Application information
TS4997
4
4.1
Application information
General description
The TS4997 integrates two monolithic full-differential input/output power amplifiers with two selectable standby pins dedicated for each channel. The gain of each channel is set by external input resistors. The TS4997 also features 3D effect enhancements that can be programmed through a two digital input pin interface that allows changing 3D effect levels in three steps.
4.2
Differential configuration principle
The TS4997 also includes a common mode feedback loop that controls the output bias value to average it at VCC/2 for any DC common mode input voltage. This allows maximum output voltage swing, and therefore, to maximize the output power. Moreover, as the load is connected differentially instead of single-ended, output power is four times higher for the same power supply voltage. The advantages of a full-differential amplifier are:
High PSRR (power supply rejection ratio), High common mode noise rejection, Vir tually no pops&clicks without additional circuitry, giving a faster startup time compared to conventional single-ended input amplifiers, Easier interfacing with differential output audio DAC, No input coupling capacitors required due to common mode feedback loop.
In theory, the filtering of the internal bias by an external bypass capacitor is not necessary. However, to reach maximum performance in all tolerance situations, it is recommended to keep this option. The only constraint is that the differential function is directly linked to external resistor mismatching, therefore you must pay particular attention to this mismatching in order to obtain the best performance from the amplifier.
4.3
Gain in typical application schematic
A typical differential application is shown in Figure 1 on page 3. The value of the differential gain of each amplifier is dependent on the values of external input resistors RIN1 to RIN4 and of integrated feedback resistors with fixed value. In the flat region of the frequency-response curve (no CIN effect), the differential gain of each channel is expressed by the relation given in Equation 1. Equation 1
AV
diff
Rf e e d VO + VO = ----------------------------------------------------- = ------------- = 5------------0 k D i f fi n p u t + D i f fi n p u t RI N RI N
where RIN = RIN1 = RIN2 = RIN3 = RIN4 expressed in k and Rfeed = 50k (value of internal feedback resistors).
20/34
TS4997
Application information Due to the tolerance on the internal 50k feedback resistors, the differential gain will be in the range (no tolerance on RIN):
4------------0 k A V 6------------0 k diff RI N RI N
The difference of resistance between input resistors of each channel have direct influence on the PSRR, CMRR and other amplifier parameters. In order to reach maximum performance, we recommend matching the input resistors RIN1, RIN2, RIN3, and RIN4 with a maximum tolerance of 1%. Note: For the rest of this section, Avdiff will be called AV to simplify the mathematical expressions.
4.4
Common mode feedback loop limitations
As explained previously, the common mode feedback loop allows the output DC bias voltage to be averaged at VCC/2 for any DC common mode bias input voltage. Due to the VICM limitation of the input stage (see Table 3 on page 4), the common mode feedback loop can fulfil its role only within the defined range. This range depends upon the values of VCC, RIN and Rfeed (AV). To have a good estimation of the VICM value, use the following formula: Equation 2
VC C × RI N + 2 × Vi c × 5 0 k VC C × RI N + 2 × Vi c × Rf e e d V I C M = -------------------------------------------------------------------------- = -------------------------------------------------------------------------- ( V ) 2 × ( R I N + Rf e e d ) 2 × ( R I N + 50 k )
with VCC in volts, RIN in k and
D i f fi n p u t + + D i f fi n p u t V i c = -----------------------------------------------------2 (V)
The result of the calculation must be in the range:
G N D VI C M VC C 1 V
Due to the +/-20% tolerance on the 50k feedback resistors Rfeed (no tolerance on RIN), it is also important to check that the VICM remains in this range at the tolerance limits:
V C × R I + 2 × V i × 60 k V C × R I + 2 × V i × 40 k --------C--------------N------------------------c--------------------- V I C M --------C--------------N-----------------------c--------------------- ( V ) -------2 × ( R I N + 40 k ) 2 × ( R I N + 60 k )
If the result of the VICM calculation is not in this range, an input coupling capacitor must be used. Example: VCC = 2.7V, AV = 2, and Vic = 2.2V. With internal resistors Rfeed = 50k, calculated external resistors are RIN = Rfeed/AV = 25k , VCC = 2.7V and Vic = 2.2V, which gives VICM = 1.92V. Taking into account the tolerance on the feedback resistors, with Rfeed = 40k the common mode input voltage is VICM = 1.87V and with Rfeed = 60k it is VICM = 1.95V. , These values are not in range from GND to VCC - 1V = 1.7V, therefore input coupling capacitors are required. Alternatively, you can change the Vic value.
21/34
Application information
TS4997
4.5
Low frequency response
The input coupling capacitors block the DC part of the input signal at the amplifier inputs. In the low frequency region, CIN starts to have an effect. CIN and RIN form a first-order high pass filter with a -3dB cut-off frequency.
1 F C L = ---------------------------------------------- ( H z ) 2 × × RI N × CI N
with RIN expressed in and CIN expressed in F. So, for a desired -3dB cut-off frequency we can calculate CIN:
1 C I N = ----------------------------------------------- ( F ) 2 × × RI N × FC L
From Figure 64, you can easily establish the CIN value required for a -3 dB cut-off frequency for some typical cases. Figure 64. -3dB lower cut-off frequency vs. input capacitance
Tam b=25 C
Low -3dB Cut Off Frequency (Hz)
100
R in = 6 .2 k G ~18 dB
R in = 1 2 k G ~12d B 10 R in = 2 4 k G ~6 dB 0 .2 0 .4 0 .6 0 .8 1
0 .1
In p u t Capacitor Cin (F)
4.6
3D effect enhancement
The TS4997 features 3D audio effect which can be programmed at three discrete levels (LOW, MEDIUM, HIGH) through input pins 3D1 and 3D0 which provide a digital interface. The correspondence between the logic levels of this interface and 3D effect levels are shown in Table 9. The 3D audio effect applied to stereo audio signals evokes perception of spatial hearing and improves this effect in cases where the stereo speakers are too close to each other, such as in small handheld devices, or mobile equipment. The perceived amount of 3D effect is also dependent on many factors such as speaker position, distance between speakers and listener, frequency spectrum of audio signal, or difference of signal between left and right channel. In some cases, the volume can increase when switching on the 3D effect. This factor is dependent on the composition of the stereo audio signal and its frequency spectrum.
22/34
TS4997 Table 9. 3D effect settings
3D effect level OFF LOW MEDIUM HIGH 3D0 0 0 1 1
Application information
3D1 0 1 0 1
4.7
Power dissipation and efficiency
Assumptions:
Load voltage and current are sinusoidal (Vout and Iout) Supply voltage is a pure DC source (VCC)
The output voltage is:
V o u t = V p e a k sint (V)
and
Vo u t I o u t = ------------ (A) RL
and
Vp e a k 2 P o u t = -------------------- (W) 2R L
Therefore, the average current delivered by the supply voltage is: Equation 3
Vp e a k I c c A V G = 2 ---------------- (A) R L
The power delivered by the supply voltage is: Equation 4
Psupply = VCC IccAVG (W)
Therefore, the power dissipated by each amplifier is: Pdiss = Psupply - Pout (W)
2 2 VC C P d i s s = ---------------------- P o u t P o u t ( W ) RL
23/34
Application information and the maximum value is obtained when:
Pdiss -------------------- = 0 P o u t
TS4997
and its value is: Equation 5
Pdiss max = 2 Vcc2 2RL (W)
Note:
This maximum value is only dependent on the power supply voltage and load values. The efficiency is the ratio between the output power and the power supply: Equation 6
Po u t V p e a k = ------------------ = -------------------Ps u p p l y 4Vcc
The maximum theoretical value is reached when Vpeak = VCC, so:
= -- = 78.5% -4
The TS4997 is stereo amplifier so it has two power amplifiers. Each amplifier produces heat due to its power dissipation. Therefore, the maximum die temperature is the sum of each amplifier's maximum power dissipation. It is calculated as follows:
Pdiss 1 = Power dissipation of left channel power amplifier Pdiss 2 = Power dissipation of right channel power amplifier Total Pdiss =Pdiss 1 + Pdiss 2 (W)
In most cases, Pdiss 1 = Pdiss 2, giving:
4 2 VC C T o t a l P d i s s = 2 × P d i s s 1 = ---------------------- P o u t 2 P o u t ( W ) RL
The maximum die temperature allowable for the TS4997 is 150C. In case of overheating, a thermal shutdown protection set to 150C, puts the TS4997 in standby until the temperature of the die is reduced by about 5C. To calculate the maximum ambient temperature Tamb allowable, you need to know:
the power supply voltage value, VCC the load resistor value, RL the package type, RTHJA
Example: VCC=5V, RL=8, RTHJAQFN16=85C/W (with 2-layer PCB with vias). Using the power dissipation formula given in Equation 5, the maximum dissipated power per channel is: Pdissmax = 633mW And the power dissipated by both channels is: Total Pdissmax = 2 x Pdissmax = 1266mW
24/34
TS4997 Tamb is calculated as follows: Equation 7
T a m b = 150 C R T J H A × T o t a l Pd i s s m a x
Application information
Therefore, the maximum allowable value for Tamb is: Tamb = 150 - 85 x 2 x 1.266=42.4C If a 4-layer PCB with vias is used, RTHJAQFN16 = 45C/W and the maximum allowable value for Tamb in this case is: Tamb = 150 - 45 x 2 x 1.266 = 93C
4.8
Footprint recommendation
Footprint soldering pad dimensions are given in Figure 72 on page 31. As discussed in the previous section, the maximum allowable value for ambient temperature is dependent on the thermal resistance junction to ambient RTHJA. Decreasing the RTHJA value causes better power dissipation. Based on best thermal performance, it is recommended to use 4-layer PCBs with vias to effectively remove heat from the device. It is also recommended to use vias for 2-layer PCBs to connect the package exposed pad to heatsink cooper areas placed on another layer. For proper thermal conductivity, the vias must be plated through and solder-filled. Typical thermal vias have the following dimensions: 1.2mm pitch, 0.3mm diameter. Figure 65. QFN16 footprint recommendation
4.9
Decoupling of the circuit
Two capacitors are needed to correctly bypass the TS4997: a power supply bypass capacitor CS and a bias voltage bypass capacitor Cb.
25/34
Application information
TS4997
The CS capacitor has particular influence on the THD+N at high frequencies (above 7kHz) and an indirect influence on power supply disturbances. With a value for CS of 1F, one can expect THD+N performance similar to that shown in the datasheet. In the high frequency region, if CS is lower than 1F, then THD+N increases and disturbances on the power supply rail are less filtered. On the other hand, if CS is greater than 1F, then those disturbances on the power supply rail are more filtered. The Cb capacitor has an influence on the THD+N at lower frequencies, but also impacts PSRR performance (with grounded input and in the lower frequency region).
4.10
Standby control and wake-up time tWU
The TS4997 has two dedicated standby pins (STBYL, STBYR). These pins allow to put each channel in standby mode or active mode independently. The amplifier is designed to reach close to zero pop when switching from one mode to the other. When both channels are in standby (VSTBYL = VSTBYR = GND), the circuit is in shutdown mode. When at least one of the two standby pins is released to put the device ON, the bypass capacitor Cb starts to be charged. Because Cb is directly linked to the bias of the amplifier, the bias will not work properly until the Cb voltage is correct. The time to reach this voltage is called the wake-up time or tWU and is specified in Table 4 on page 5, with Cb=1F. During the wake-up phase, the TS4997 gain is close to zero. After the wake-up time, the gain is released and set to its nominal value. If Cb has a value different from 1F, then refer to the graph in Figure 66 to establish the corresponding wake-up time. When a channel is set to standby mode, the outputs of this channel are in high impedance state. Figure 66. Typical startup time vs. bypass capacitor
100 90
Startup Time (ms)
Tamb=25C V c c = 2 .7 V V c c = 3 .3 V
80 70 60 50 40 30 0.0
Vcc=5V
0 .5
1 .0
1 .5 2 .0 2 . 5 3 .0 3 .5 B y p a s s Capacitor Cb (F)
4 .0
4 .5
26/34
TS4997
Application information
4.11
Shutdown time
When the standby command is activated (both channels put into standby mode), the time required to put the two output stages of each channel in high impedance and the internal circuitry in shutdown mode is a few microseconds.
Note:
In shutdown mode when both channels are in standby, the Bypass pin and LIN+, LIN-, RIN+, RIN- pins are shorted to ground by internal switches. This allows a quick discharge of Cb and CIN capacitors.
4.12
Pop performance
Due to its fully differential structure, the pop performance of the TS4997 is close to perfect. However, due to mismatching between internal resistors Rfeed, external resistors RIN and external input capacitors CIN, some noise might remain at startup. To eliminate the effect of mismatched components, the TS4997 includes pop reduction circuitry. With this circuitry, the TS4997 is close to zero pop for all possible common applications. In addition, when the TS4997 is in standby mode, due to the high impedance output stage in this configuration, no pop is heard.
4.13
Single-ended input configuration
It is possible to use the TS4997 in a single-ended input configuration. However, input coupling capacitors are needed in this configuration. The schematic diagram in Figure 67 shows an example of this configuration for a gain of +6dB set by the input resistors.
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Application information Figure 67. Typical single-ended input application
VCC
TS4997
3D0 Control
3D1 Control
Cs 1 uF
16
15
TS4997 - QFN16
Dif f. input LP1 330nF 24k 1 Cin2 Rin2 2 330nF 24k
LI N+ LI N-
Cin1
Rin1
3D 0 3D 1
13
Vcc
LEFT
LOU T-
12
Left Speaker
3D EFF EC T
RI GH T
+ +
LOU T+
11
8 Ohms
Dif f. input RP2
Cin3
Rin3
4
R IN -
R OUT-
9
Right Speaker
330nF
24k 3
R IN +
R OUT+
10
8 Ohms
Cin4
Rin4
Bypa ss
330nF
24k 14 BIAS
STBYL
STBY
STBYR
GN D
GN D
5
6
8
1 uF Cb
STBYL Control
The component calculations remain the same for the gain. In single-ended input configuration, the formula is:
VO + VO Rf e e d 50 k A v S E = ------------------------- = ------------- = ------------Ve RI N RI N
with RIN expressed in k .
4.14
Notes on PSRR measurement
What is the PSRR?
The PSRR is the power supply rejection ratio. The PSRR of a device is the ratio between a power supply disturbance and the result on the output. In other words, the PSRR is the ability of a device to minimize the impact of power supply disturbance to the output.
How is the PSRR measured?
The PSRR is measured as shown in Figure 68.
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STBYR Control
7
TS4997 Figure 68. PSRR measurement
Application information
Vrip ple
3D0 Control 3D1 Control
Vcc
16
15
TS4997 - QFN16
Cin1 Rin1
3D 0
4.7uF 1 Cin2 Rin2 2 4.7uF
LI N+ LI N-
3D 1
13
Vcc
LEFT
LOU T-
12 RL 8Ohms
3D EFF EC T
RI GH T
+ +
LOU T+
11
Cin3
Rin3
4
R IN -
R OUT-
9 RL 8Ohms
4.7uF 3 Cin4 Rin4
R IN +
R OUT+
10
Bypa ss
4.7uF 14 BIAS
STBYL
STBY
STBYR
GN D
GN D
5
6
8
1u F Cb
S TBY L Control
Principles of operation
The DC voltage supply (VCC) is fixed The AC sinusoidal ripple voltage (Vripple) is fixed No bypass capacitor CS is used
The PSRR value for each frequency is calculated as:
R M S( O u t p u t ) P S R R = 20 × L o g --------------------------------- ( d B ) R M S( V r i p p l e)
RMS is an rms selective measurement.
STBY R Control
7
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QFN16 package information
TS4997
5
QFN16 package information
In order to meet environmental requirements, STMicroelectronics offers these devices in ECOPACK packages. These packages have a Lead-free second level interconnect. The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an STMicroelectronics trademark. ECOPACK specifications are available at: www.st.com. Figure 69. QFN16 package
Figure 70. Pinout (top view)
3D0 3D1 BYP VCC 16 15 14 13
LINLIN+ RIN+ RIN-
1 2 3 4
12 LOUT11 LOUT+ 10 ROUT+ 9 ROUT-
5
6
7
8
GND GND STBYR STBYL
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TS4997 Figure 71. QFN16 4x4mm
QFN16 package information
Dimensions Millimeters (mm) Ref Min A A1 A3 b D 0.18 3.85 2.1 3.85 2.1 0.65 0.2 0.30 0.11 0.40 0.50 4.0 0.8 Typ 0.9 0.02 0.20 0.25 4.0 0.30 4.15 2.6 4.15 2.6 Max 1.0 0.05
*
D2 E E2
* The Exposed Pad is connected to Ground.
e K L r
Figure 72. Footprint soldering pad
Footprint data Ref A B C D E F mm 4.2 4.2 0.65 0.35 0.65 2.70
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Ordering information
TS4997
6
Ordering information
Table 10. Order codes
Temperature range -40C, +85C Package QFN16 4x4mm Packaging Tape & reel Marking Q997
Part number TS4997IQT
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TS4997
Revision history
7
Revision history
Date 10-Jan-2007 20-Feb-2007 Revision 1 2 Preliminar y data. First release. Changes
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TS4997
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