TS4997 2 x 1W differential input stereo audio amplifier with programmable 3D effects Features ■ Operating range from VCC= 2.7V to 5.5V ■ 1W output power per channel @ VCC=5V, THD+N=1%, RL=8Ω ■ 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 QFN16 4x4mm Pin connections (top view) 3D0 3D1 BYP VCC Applications 16 15 14 13 ■ Cellular mobile phones ■ Notebook and PDA computers LIN- 1 12 LOUT- ■ LCD monitors and TVs LIN+ 2 11 LOUT+ ■ Portable audio devices RIN+ 3 10 ROUT+ RIN- 4 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 8Ω load @ 5V. 3D effects enhancement is programmed through a two digital input pin interface that allows more flexibility on each output audio sound channel. February 2007 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. Rev 2 1/34 www.st.com 34 Contents TS4997 Contents 1 Typical application schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.1 General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.2 Differential configuration principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.3 Gain in typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.4 Common mode feedback loop limitations . . . . . . . . . . . . . . . . . . . . . . . . . 21 4.5 Low frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 4.6 3D effect enhancement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 4.7 Power dissipation and efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 4.8 Footprint recommendation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 4.9 Decoupling of the circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 4.10 Standby control and wake-up time tWU 4.11 Shutdown time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 4.12 Pop performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 4.13 Single-ended input configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 4.14 Notes on PSRR measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5 QFN16 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 6 Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 7 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2/34 TS4997 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 24k Cin2 Rin2 P1 1 LI N- 2 LI N+ 330nF 24k Diff. input R- Cin3 Rin3 4 RIN- 330nF 24k 3 RIN+ P3 Cin4 Rin4 330nF 24k - LOUT- 12 + LOUT+ 11 - ROUT- 9 + ROUT+ 10 Left Speaker LEFT P2 Diff. input L+ 3D1 330nF Vcc 3D0 Rin1 1uF 13 TS4997 - QFN16 Cin1 3D1 Control 16 Optional Diff. input L- Cs 15 3D0 Control VCC 3D EFFECT 8 Ohms Right Speaker RIGHT 8 Ohms P4 Bypass STBYR 7 STBYL Control 1uF Cb GND STBYL GND STBY 8 BIAS Table 1. STBYR Control 14 6 Diff. input R+ 5 1 Typical application schematics External component descriptions Components Functional description RIN Input resistors that set the closed loop gain in conjunction with a fixed internal feedback resistor (Gain = Rfeed/RIN, where Rfeed = 50kΩ). CIN 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 π x RIN x CIN)). CS Supply bypass capacitors that provides power supply filtering. CB Bypass pin capacitor that provides half supply filtering. 3/34 Absolute maximum ratings 2 TS4997 Absolute maximum ratings Table 2. Absolute maximum ratings Symbol VCC Vi Parameter Value Unit 6 V GND to VCC V Supply voltage (1) Input voltage (2) Toper Operating free air temperature range -40 to + 85 °C Tstg Storage temperature -65 to +150 °C Maximum junction temperature 150 °C Thermal resistance junction to ambient 120 °C/W Tj Rthja Pd Power dissipation Internally limited ESD Human body model (3) Digital pins STBYL, STBYR, 3D0, 3D1 2 1.5 kV ESD Machine model 200 V Latch-up immunity 200 mA 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. Operating conditions Symbol Parameter VCC Supply voltage VICM Common mode input voltage range Unit 2.7 to 5.5 V GND to VCC - 1V V VIL 3D0 - 3D1 maximum low input voltage 0.4 V VIH 3D0 - 3D1 minimum high input voltage 1.3 V 1.3 ≤ VSTBY ≤ VCC GND ≤ VSTBY ≤0.4 V ≥4 Ω ≥1 MΩ VSTBY RL Standby voltage input: Device ON Device OFF Load resistor ROUT/GND Output resistor to GND (VSTBY = GND) 4/34 Value TSD Thermal shutdown temperature 150 °C Rthja Thermal resistance junction to ambient QFN16(1) QFN16(2) 45 85 °C/W 1. When mounted on a 4-layer PCB with vias. 2. When mounted on a 2-layer PCB with vias. TS4997 Electrical characteristics 3 Electrical characteristics Table 4. VCC = +5V, GND = 0V, Tamb = 25°C (unless otherwise specified) Symbol Typ. Max. Unit Supply current No input signal, no load, left and right channel active 7.4 9.6 mA Standby current (1) No input signal, VSTBYL = GND, VSTBYR = GND, RL = 8Ω 10 2000 nA Voo Output offset voltage No input signal, RL = 8Ω 1 35 mV Po Output power THD = 1% Max, F = 1kHz, RL = 8Ω ICC ISTBY THD + N PSRR CMRR Parameter Min. 800 Total harmonic distortion + noise Po = 700mWrms, G = 6dB, RL = 8Ω, 20Hz ≤ F ≤ 20kHz Power supply rejection ratio(2), inputs grounded RL = 8Ω, G = 6dB, Cb = 1µF, Vripple = 200mVpp, 3D effect off F = 217Hz F = 1kHz Crosstalk VN mW 0.5 % dB 80 75 Common mode rejection ratio(3) RL = 8Ω, G = 6dB, Cb = 1µF, Vincm = 200mVpp, 3D effect off dB 57 57 F = 217Hz F = 1kHz SNR 1000 Signal-to-noise ratio A-weighted, G = 6dB, Cb = 1µF, RL = 8Ω, 3D effect off (THD + N ≤ 0.5%, 20Hz < F < 20kHz) Channel separation, RL = 8Ω, G = 6dB, 3D effect off F = 1kHz F = 20Hz to 20kHz 108 dB 105 80 dB Output voltage noise, F = 20Hz to 20kHz, RL = 8Ω, G=6dB Cb = 1µF, 3D effect off μVrms 15 10 Unweighted A-weighted 40 kΩ ---------------- 50 kΩ ---------------- 60 kΩ ---------------- Gain Gain value (RIN in kΩ) tWU Wake-up time (Cb = 1µF) 46 ms tSTBY Standby time (Cb = 1µF) 10 µs ΦM Phase margin at unity gain RL = 8Ω, CL = 500pF 65 Degrees GM Gain margin, RL = 8Ω, CL = 500pF 15 dB GBP Gain bandwidth product, RL = 8Ω 1.5 MHz R IN R IN R IN V/V 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)). 5/34 Electrical characteristics Table 5. TS4997 VCC = +3.3V, GND = 0V, Tamb = 25°C (unless otherwise specified) Symbol Typ. Max. Unit Supply current No input signal, no load, left and right channel active 6.6 8.6 mA Standby current (1) No input signal, VSTBYL = GND, VSTBYR = GND, RL = 8Ω 10 2000 nA Voo Output offset voltage No input signal, RL = 8Ω 1 35 mV Po Output power THD = 1% Max, F = 1kHz, RL = 8Ω ICC ISTBY THD + N PSRR CMRR Parameter Min. 370 Total harmonic distortion + noise Po = 300mWrms, G = 6dB, RL = 8Ω, 20Hz ≤ F ≤ 20kHz Power supply rejection ratio(2), inputs grounded RL = 8Ω, G = 6dB, Cb = 1µF, Vripple = 200mVpp, 3D effect off F = 217Hz F = 1kHz Crosstalk VN mW 0.5 % dB 80 75 Common mode rejection ratio(3) RL = 8Ω, G = 6dB, Cb = 1µF, Vincm = 200mVpp, 3D effect off dB 57 57 F = 217Hz F = 1kHz SNR 460 Signal-to-noise ratio A-weighted, G = 6dB, Cb = 1µF, RL = 8Ω, 3D effect off (THD + N ≤ 0.5%, 20Hz < F < 20kHz) Channel separation, RL = 8Ω, G = 6dB, 3D effect off F = 1kHz F = 20Hz to 20kHz 104 dB 105 80 dB Output voltage noise, F = 20Hz to 20kHz, RL = 8Ω, G=6dB Cb = 1µF, 3D effect off μVrms 15 10 Unweighted A-weighted 40 kΩ ---------------- 50 kΩ ---------------- 60 kΩ ---------------- Gain Gain value (RIN in kΩ) tWU Wake-up time (Cb = 1µF) 47 ms tSTBY Standby time (Cb = 1µF) 10 µs ΦM Phase margin at unity gain RL = 8Ω, CL = 500pF 65 Degrees GM Gain margin RL = 8Ω, CL = 500pF 15 dB GBP Gain bandwidth product RL = 8Ω 1.5 MHz R IN R IN R IN 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)). 6/34 V/V TS4997 Table 6. Electrical characteristics VCC = +2.7V, GND = 0V, Tamb = 25°C (unless otherwise specified) Symbol Typ. Max. Unit Supply current No input signal, no load, left and right channel active 6.2 8.1 mA Standby current (1) No input signal, VSTBYL = GND, VSTBYR = GND, RL = 8Ω 10 2000 nA Voo Output offset voltage No input signal, RL = 8Ω 1 35 mV Po Output power THD = 1% Max, F = 1kHz, RL = 8Ω ICC ISTBY THD + N PSRR CMRR Parameter Min. 220 Total harmonic distortion + noise Po = 200mWrms, G = 6dB, RL = 8Ω, 20Hz ≤ F ≤ 20kHz Power supply rejection ratio(2), inputs grounded RL = 8Ω, G = 6dB, Cb = 1µF, Vripple = 200mVpp, 3D effect off F = 217Hz F = 1kHz Crosstalk VN mW 0.5 % dB 76 73 Common mode rejection ratio(3) RL = 8Ω, G = 6dB, Cb = 1µF, Vincm = 200mVpp, 3D effect off dB 57 57 F = 217Hz F = 1kHz SNR 295 Signal-to-noise ratio A-weighted, G = 6dB, Cb = 1µF, RL = 8Ω, 3D effect off (THD + N ≤ 0.5%, 20Hz < F < 20kHz) Channel separation, RL = 8Ω, G = 6dB, 3D effect off F = 1kHz F = 20Hz to 20kHz 102 dB 105 80 dB Output voltage noise, F = 20Hz to 20kHz, RL = 8Ω, G=6dB Cb = 1µF, 3D effect off μVrms 15 10 Unweighted A-weighted 40 kΩ ---------------- 50 kΩ ---------------- 60 kΩ ---------------- Gain Gain value (RIN in kΩ) tWU Wake-up time (Cb = 1µF) 46 ms tSTBY Standby time (Cb = 1µF) 10 µs ΦM Phase margin at unity gain RL = 8Ω, CL = 500pF 65 Degrees GM Gain margin RL = 8Ω, CL = 500pF 15 dB GBP Gain bandwidth product RL = 8Ω 1.5 MHz R IN R IN R IN V/V 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. TS4997 Index of graphics Description 8/34 Figure Page THD+N vs. output power Figure 2 to 13 page 9 to page 10 THD+N vs. frequency Figure 14 to 19 page 11 PSRR vs. frequency Figure 20 to 28 page 12 to page 13 PSRR vs. common mode input voltage Figure 29 page 13 CMRR vs. frequency Figure 30 to 35 page 13 to page 14 CMRR vs. common mode input voltage Figure 36 page 14 Crosstalk vs. frequency Figure 37 to 39 page 14 to page 15 SNR vs. power supply voltage Figure 40 to 45 page 15 to page 16 Differential DC output voltage vs. common mode input voltage Figure 46 to 48 page 16 Current consumption vs. power supply voltage Figure 49 page 16 Current consumption vs. standby voltage Figure 50 to 52 page 17 Standby current vs. power supply voltage Figure 53 page 17 Frequency response Figure 54 to 56 page 17 to page 18 Output power vs. load resistance Figure 57 page 18 Output power vs. power supply voltage Figure 58 to 59 page 18 Power dissipation vs. output power Figure 60 to 62 page 18 to page 19 Power derating curves Figure 63 page 19 TS4997 Figure 2. Electrical characteristics THD+N vs. output power Figure 3. 10 RL = 4 Ω G = +6dB F = 1kHz Cb = 1 μ F 1 BW < 125kHz Tamb = 25 ° C Vcc=3.3V Vcc=2.7V 0.1 0.01 1E-3 RL = 4 Ω G = +12dB F = 1kHz Cb = 1 μ F 1 BW < 125kHz Tamb = 25 ° C Vcc=5V THD + N (%) THD + N (%) 10 THD+N vs. output power 0.01 0.1 Vcc=3.3V Vcc=2.7V 0.1 0.01 1E-3 1 Vcc=5V 0.01 Output power (W) Figure 4. THD+N vs. output power Figure 5. THD+N vs. output power Vcc=3.3V Vcc=2.7V 0.01 1E-3 RL = 8 Ω G = +12dB F = 1kHz Cb = 1 μ F 1 BW < 125kHz Tamb = 25 ° C Vcc=5V 0.1 0.01 0.1 0.01 0.1 1 Output power (W) THD+N vs. output power Figure 7. 10 THD+N vs. output power 10 RL = 16 Ω G = +6dB F = 1kHz Cb = 1 μ F 1 BW < 125kHz Tamb = 25 ° C Vcc=5V Vcc=3.3V THD + N (%) THD + N (%) Vcc=3.3V Vcc=2.7V 0.01 1E-3 1 Vcc=5V 0.1 Output power (W) Vcc=2.7V 0.1 0.01 1E-3 1 10 RL = 8 Ω G = +6dB F = 1kHz Cb = 1 μ F 1 BW < 125kHz Tamb = 25 ° C THD + N (%) THD + N (%) 10 Figure 6. 0.1 Output power (W) 0.01 0.1 Output power (W) 1 RL = 16 Ω G = +12dB F = 1kHz Cb = 1 μ F 1 BW < 125kHz Tamb = 25 ° C Vcc=5V Vcc=3.3V Vcc=2.7V 0.1 0.01 1E-3 0.01 0.1 1 Output power (W) 9/34 Electrical characteristics Figure 8. TS4997 THD+N vs. output power Figure 9. 10 10 RL = 4 Ω G = +12dB F = 10kHz Cb = 1 μ F 1 BW < 125kHz Tamb = 25 ° C Vcc=5V Vcc=3.3V THD + N (%) THD + N (%) RL = 4 Ω G = +6dB F = 10kHz Cb = 1 μ F 1 BW < 125kHz Tamb = 25 ° C Vcc=2.7V 0.1 0.01 1E-3 THD+N vs. output power 0.01 0.1 Vcc=3.3V Vcc=2.7V 0.1 0.01 1E-3 1 Vcc=5V 0.01 Output power (W) Figure 10. THD+N vs. output power 10 RL = 8 Ω G = +12dB F = 10kHz Cb = 1 μ F 1 BW < 125kHz Tamb = 25 ° C Vcc=5V Vcc=3.3V THD + N (%) THD + N (%) RL = 8 Ω G = +6dB F = 10kHz Cb = 1 μ F 1 BW < 125kHz Tamb = 25 ° C Vcc=2.7V 0.1 0.01 0.1 0.1 1 Figure 13. THD+N vs. output power 10 10 RL = 16 Ω G = +6dB F = 10kHz Cb = 1 μ F 1 BW < 125kHz Tamb = 25 ° C Vcc=5V Vcc=3.3V THD + N (%) THD + N (%) 0.01 Output power (W) Figure 12. THD+N vs. output power Vcc=2.7V 0.1 0.01 0.1 Output power (W) 10/34 Vcc=3.3V Vcc=2.7V 0.01 1E-3 1 Vcc=5V 0.1 Output power (W) 0.01 1E-3 1 Figure 11. THD+N vs. output power 10 0.01 1E-3 0.1 Output power (W) 1 RL = 16 Ω G = +12dB F = 10kHz Cb = 1 μ F 1 BW < 125kHz Tamb = 25 ° C Vcc=5V Vcc=3.3V Vcc=2.7V 0.1 0.01 1E-3 0.01 0.1 Output power (W) 1 TS4997 Electrical characteristics Figure 14. THD+N vs. frequency 10 10 RL = 4 Ω G = +6dB Cb = 1 μ F BW < 125kHz Tamb = 25 ° C Vcc=5V Pout=950mW 1 Vcc=3.3V Pout=430mW THD + N (%) THD + N (%) 1 Figure 15. THD+N vs. frequency 0.1 RL = 4 Ω G = +12dB Cb = 1 μ F BW < 125kHz Tamb = 25 ° C Vcc=5V Pout=950mW Vcc=3.3V Pout=430mW 0.1 Vcc=2.7V Pout=260mW Vcc=2.7V Pout=260mW 0.01 100 1000 0.01 10000 100 Frequency (Hz) Figure 16. THD+N vs. frequency 10 Vcc=5V Pout=700mW 1 Vcc=3.3V Pout=300mW THD + N (%) THD + N (%) RL = 8 Ω G = +6dB Cb = 1 μ F BW < 125kHz 1 Tamb = 25 ° C 0.01 Vcc=2.7V Pout=200mW 100 1000 Vcc=2.7V Pout=200mW 0.1 100 10 RL = 16 Ω G = +6dB Cb = 1 μ F BW < 125kHz 1 Tamb = 25 ° C RL = 16 Ω G = +12dB Cb = 1 μ F BW < 125kHz 1 Tamb = 25 ° C Vcc=5V Pout=450mW Vcc=3.3V Pout=200mW THD + N (%) THD + N (%) 10000 Figure 19. THD+N vs. frequency 10 Vcc=2.7V Pout=120mW 100 1000 Frequency (Hz) Figure 18. THD+N vs. frequency 0.01 Vcc=5V Pout=700mW Vcc=3.3V Pout=300mW 0.01 10000 RL = 8 Ω G = +12dB Cb = 1 μ F BW < 125kHz Tamb = 25 ° C Frequency (Hz) 0.1 10000 Figure 17. THD+N vs. frequency 10 0.1 1000 Frequency (Hz) 1000 Frequency (Hz) 10000 Vcc=5V Pout=450mW Vcc=3.3V Pout=200mW Vcc=2.7V Pout=120mW 0.1 0.01 100 1000 10000 Frequency (Hz) 11/34 Electrical characteristics TS4997 Figure 20. PSRR vs. frequency Figure 21. PSRR vs. frequency 0 -20 -30 PSRR (dB) -40 0 Vcc = 5V Vripple = 200mVpp G = +6dB Cb = 1 μ F, Cin = 4.7 μ F Inputs Grounded Tamb = 25 ° C -10 -20 3D MEDIUM -50 3D LOW -60 -30 3D HIGH PSRR (dB) -10 -40 3D MEDIUM -70 -80 1000 3D OFF -90 3D OFF 100 3D LOW -60 -80 -100 3D HIGH -50 -70 -90 Vcc = 5V Vripple = 200mVpp G = +12dB Cb = 1 μ F, Cin = 4.7 μ F Inputs Grounded Tamb = 25 ° C -100 10000 100 1000 Frequency (Hz) Frequency (Hz) Figure 22. PSRR vs. frequency Figure 23. PSRR vs. frequency 0 -10 -20 -30 0 Vcc = 5V Vripple = 200mVpp Cb = 1 μ F Inputs Floating Tamb = 25 ° C -10 -20 PSRR (dB) PSRR (dB) 3D MEDIUM -50 3D LOW -60 -30 3D HIGH -40 -40 3D HIGH 3D MEDIUM 3D LOW -60 -70 -80 -80 -90 Vcc = 3.3V Vripple = 200mVpp G = +6dB Cb = 1 μ F, Cin = 4.7 μ F Inputs Grounded Tamb = 25 ° C -50 -70 -100 -90 3D OFF 100 1000 -100 10000 3D OFF 100 1000 Frequency (Hz) Frequency (Hz) Figure 24. PSRR vs. frequency Figure 25. PSRR vs. frequency 0 -20 -30 PSRR (dB) -40 -10 -20 3D MEDIUM 3D LOW -60 -70 Vcc = 3.3V Vripple = 200mVpp Cb = 1 μ F Inputs Floating Tamb = 25 ° C 3D HIGH -40 3D MEDIUM -50 3D LOW -60 -70 -80 -80 3D OFF -90 100 1000 Frequency (Hz) 12/34 -30 3D HIGH -50 -100 10000 0 Vcc = 3.3V Vripple = 200mVpp G = +12dB Cb = 1 μ F, Cin = 4.7 μ F Inputs Grounded Tamb = 25 ° C PSRR (dB) -10 10000 -90 10000 -100 3D OFF 100 1000 Frequency (Hz) 10000 TS4997 Electrical characteristics Figure 26. PSRR vs. frequency Figure 27. PSRR vs. frequency 0 -20 PSRR (dB) -30 -40 0 Vcc = 2.7V Vripple = 200mVpp G = +6dB Cb = 1 μ F, Cin = 4.7 μ F Inputs Grounded Tamb = 25 ° C -10 -20 3D MEDIUM -50 3D LOW -60 -30 3D HIGH PSRR (dB) -10 -40 -70 -80 1000 3D OFF -90 3D OFF 100 3D MEDIUM 3D LOW -60 -80 -100 -100 10000 100 Frequency (Hz) 0 Vcc = 2.7V Vripple = 200mVpp Cb = 1 μ F Inputs Floating Tamb = 25 ° C -20 3D HIGH -40 3D MEDIUM -50 3D LOW -60 -30 -40 -60 -80 -70 3D OFF 100 1000 -90 10000 Figure 30. CMRR vs. frequency 3D LOW -10 -20 3D HIGH 3D MEDIUM -50 3 4 5 -30 Vcc = 5V RL ≥ 8 Ω G = +12dB Vic = 200mVpp Cb = 1 μ F, Cin = 4.7 μ F Tamb = 25°C 3D LOW 3D HIGH 3D MEDIUM -40 -50 -60 -70 2 0 Vcc = 5V RL ≥ 8 Ω G = +6dB Vic = 200mVpp Cb = 1 μ F, Cin = 4.7 μ F Tamb = 25°C CMRR (dB) CMRR (dB) -40 1 Figure 31. CMRR vs. frequency 0 -30 0 Common Mode Input Voltage (V) Frequency (Hz) -20 Vcc=5V -80 -90 -10 Vcc=3.3V Vcc=2.7V -50 -70 -100 Vripple = 200mVpp F = 217Hz, G = +6dB Cb = 1 μ F, RL ≥ 8 Ω 3D Effect OFF Tamb = 25°C -10 PSRR (dB) PSRR (dB) -30 10000 Figure 29. PSRR vs. common mode input voltage 0 -20 1000 Frequency (Hz) Figure 28. PSRR vs. frequency -10 3D HIGH -50 -70 -90 Vcc = 2.7V Vripple = 200mVpp G = +12dB Cb = 1 μ F, Cin = 4.7 μ F Inputs Grounded Tamb = 25 ° C -60 3D OFF 100 1000 Frequency (Hz) 10000 -70 3D OFF 100 1000 10000 Frequency (Hz) 13/34 Electrical characteristics TS4997 Figure 32. CMRR vs. frequency Figure 33. CMRR vs. frequency 0 0 Vcc = 3.3V RL ≥ 8 Ω G = +6dB Vic = 200mVpp Cb = 1 μ F, Cin = 4.7 μ F Tamb = 25°C CMRR (dB) -20 -30 3D LOW -40 -10 -20 CMRR (dB) -10 3D HIGH 3D MEDIUM -50 -30 Vcc = 3.3V RL ≥ 8 Ω G = +12dB Vic = 200mVpp Cb = 1 μ F, Cin = 4.7 μ F Tamb = 25°C 3D LOW -60 3D OFF -70 100 1000 -70 10000 3D OFF 100 Frequency (Hz) 0 Vcc = 2.7V RL ≥ 8 Ω G = +6dB Vic = 200mVpp Cb = 1 μ F, Cin = 4.7 μ F Tamb = 25°C -20 -30 3D LOW -40 -10 -20 CMRR (dB) -10 CMRR (dB) 10000 Figure 35. CMRR vs. frequency 0 3DHIGH 3D MEDIUM -30 Vcc = 2.7V RL ≥ 8 Ω G = +12dB Vic = 200mVpp Cb = 1 μ F, Cin = 4.7 μ F Tamb = 25°C 3D LOW 3D HIGH 3D MEDIUM -40 -50 -50 -60 -60 3D OFF -70 100 1000 -70 10000 3D OFF 100 Frequency (Hz) 0 Vripple = 200mVpp F = 217Hz, G = +6dB Cb = 1 μ F, RL ≥ 8 Ω 3D Effect OFF Tamb = 25°C -10 -10 -20 Crosstalk Level (dB) 0 -20 -30 Vcc=3.3V Vcc=2.7V -40 10000 Figure 37. Crosstalk vs. frequency 20 10 1000 Frequency (Hz) Figure 36. CMRR vs. common mode input voltage CMRR (dB) 1000 Frequency (Hz) Figure 34. CMRR vs. frequency -50 -60 -30 -40 RL = 4 Ω G = +6dB Cin = 1 μ F, Cb = 1 μ F 3D Effect OFF Tamb = 25 ° C -50 Vcc=5V Vcc=3.3V Vcc=2.7V -60 -70 -80 -90 -100 Vcc=5V -70 -110 -120 0 1 2 3 Common Mode Input Voltage (V) 14/34 3D MEDIUM -40 -50 -60 -80 3D HIGH 4 5 100 1000 Frequency (Hz) 10000 TS4997 Electrical characteristics Figure 38. Crosstalk vs. frequency Figure 39. Crosstalk vs. frequency 0 Crosstalk Level (dB) -20 -30 -40 0 RL = 8 Ω G = +6dB Cin = 1 μ F, Cb = 1 μ F 3D Effect OFF Tamb = 25 ° C -10 -20 Crosstalk Level (dB) -10 -50 Vcc=5V Vcc=3.3V Vcc=2.7V -60 -70 -80 -90 -30 -40 -50 -70 -80 -90 -100 -110 -110 100 1000 -120 10000 Vcc=5V Vcc=3.3V Vcc=2.7V -60 -100 -120 RL = 16 Ω G = +6dB Cin = 1 μ F, Cb = 1 μ F 3D Effect OFF Tamb = 25 ° C 100 1000 Frequency (Hz) Figure 41. SNR vs. power supply voltage Singnal to Noise Ratio (dB) Singnal to Noise Ratio (dB) Figure 40. SNR vs. power supply voltage 110 108 3D OFF 106 104 102 100 3D LOW 98 96 94 92 90 88 86 3D HIGH 84 82 80 2.5 3.0 3D MEDIUM A - Weighted filter F = 1kHz G = +6dB, RL = 4 Ω THD + N < 0.5% Tamb = 25 ° C 3.5 4.0 4.5 5.0 5.5 110 108 3D OFF 106 104 102 3D LOW 100 98 96 94 92 3D MIDDLE 90 3D HIGH 88 86 84 82 80 2.5 3.0 3.5 4.0 Supply Voltage (V) 4.5 5.0 5.5 Singnal to Noise Ratio (dB) Singnal to Noise Ratio (dB) 4.5 5.0 5.5 Figure 43. SNR vs. power supply voltage A - Weighted filter F = 1kHz G = +6dB ,RL = 16 Ω THD + N < 0.5% Tamb = 25 ° C Supply Voltage (V) A - weighted filter F = 1kHz G = +6dB ,RL = 8 Ω THD + N < 0.5% Tamb = 25 ° C Supply Voltage (V) Figure 42. SNR vs. power supply voltage 110 108 3D OFF 106 104 102 3D LOW 100 98 96 94 92 3D MIDDLE 90 3D HIGH 88 86 84 82 80 2.5 3.0 3.5 4.0 10000 Frequency (Hz) 110 108 106 3D OFF 104 102 100 98 3D LOW 96 94 92 90 88 86 84 3D HIGH 82 80 78 76 2.5 3.0 3D MEDIUM Unweighted filter (20Hz to 20kHz) F = 1kHz G = +6dB, RL = 4 Ω THD + N < 0.5% Tamb = 25 ° C 3.5 4.0 4.5 5.0 5.5 Supply Voltage (V) 15/34 Electrical characteristics TS4997 110 108 3D OFF 106 104 102 100 3D LOW 98 96 94 92 90 88 86 3D HIGH 84 82 80 2.5 3.0 Figure 45. SNR vs. power supply voltage Singnal to Noise Ratio (dB) Singnal to Noise Ratio (dB) Figure 44. SNR vs. power supply voltage 3D MEDIUM Unweighted filter (20Hz to 20kHz) F = 1kHz G = +6dB, RL = 8 Ω THD + N < 0.5% Tamb = 25 ° C 3.5 4.0 4.5 5.0 5.5 110 108 3D OFF 106 104 102 100 3D LOW 98 96 94 92 90 88 3D HIGH 86 84 82 80 2.5 3.0 3D MEDIUM Unweighted filter (20Hz to 20kHz) F = 1kHz G = +6dB, RL = 16 Ω THD + N < 0.5% Tamb = 25 ° C 3.5 Supply Voltage (V) Figure 46. Differential DC output voltage vs. common mode input voltage 3D MEDIUM |Voo| (mV) |Voo| (mV) 3D MEDIUM 3D OFF 0.01 3D LOW 1 0.1 3D OFF 0.01 0 1 2 3 4 5 1E-3 0.0 0.5 Common Mode Input Voltage (V) 2.0 2.5 3.0 No load Tamb = 25 ° C 7 Current Consumption (mA) 10 1.5 Figure 49. Current consumption vs. power supply voltage 8 1000 Vcc = 2.7V G = +6dB Tamb = 25 ° C 100 3D MEDIUM 3D HIGH 1.0 Common Mode Input Voltage (V) Figure 48. Differential DC output voltage vs. common mode input voltage |Voo| (mV) 5.5 3D HIGH 10 3D LOW 1 1E-3 5.0 1000 Vcc = 3.3V G = +6dB Tamb = 25 ° C 100 3D HIGH 0.1 4.5 Figure 47. Differential DC output voltage vs. common mode input voltage 1000 Vcc = 5V G = +6dB Tamb = 25 ° C 100 10 4.0 Supply Voltage (V) 3D LOW 1 0.1 3D OFF 0.01 6 5 Both channels active 4 3 2 One channel active 1 1E-3 0.0 0.5 1.0 1.5 2.0 Common Mode Input Voltage (V) 16/34 2.5 0 0 1 2 3 4 Power Supply Voltage (V) 5 TS4997 Electrical characteristics Figure 51. Current consumption vs. standby voltage 8 7 7 6 6 Current Consumption (mA) Current Consumption (mA) Figure 50. Current consumption vs. standby voltage Both channels active 5 4 3 One channel active 2 Vcc = 5V No load Tamb = 25 ° C 1 0 0 1 2 3 4 5 Both channels active 4 3 One channel active 2 0 0.0 5 Vcc = 3.3V No load Tamb = 25 ° C 1 0.5 1.0 Standby Voltage (V) Figure 52. Current consumption vs. standby voltage 2.5 3.0 1.0 No load 0.9 Tamb = 25 ° C 6 0.8 5 Both channels active 4 3 One channel active 2 Vcc = 2.7V No load Tamb = 25 ° C 1 0 0.0 Standby Current (nA) Current Consumption (mA) 2.0 Figure 53. Standby current vs. power supply voltage 7 0.5 1.0 1.5 2.0 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 2.5 0 1 Figure 54. Frequency response Cin=4.7 μ F, Rin=12k Ω Cin=680nF, Rin=12k Ω Cin=4.7 μ F, Rin=24k Ω Cin=330nF, Rin=24k Ω 20 100 1000 Frequency (Hz) 3 4 5 Figure 55. Frequency response Gain (dB) 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 2 Power Supply Voltage (V) Standby Voltage (V) Gain (dB) 1.5 Standby Voltage (V) Vcc = 5V Po = 700mW 3D Effect OFF ZL = 8 Ω + 500pF Tamb = 25 ° C 10000 20k 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Cin=4.7 μ F, Rin=12k Ω Cin=680nF, Rin=12k Ω Cin=4.7 μ F, Rin=24k Ω Cin=330nF, Rin=24k Ω 20 100 1000 Vcc = 3.3V Po = 300mW 3D Effect OFF ZL = 8 Ω + 500pF Tamb = 25 ° C 10000 20k Frequency (Hz) 17/34 Electrical characteristics TS4997 Figure 56. Frequency response 1800 Cin=4.7 μ F, Rin=12k Ω Vcc=5V 1400 Cin=680nF, Rin=12k Ω Cin=4.7 μ F, Rin=24k Ω Vcc = 2.7V Po = 200mW 3D Effect OFF ZL = 8 Ω + 500pF Tamb = 25 ° C Cin=330nF, Rin=24k Ω 20 100 Vcc=4.5V 1200 Vcc=4V 1000 Vcc=3.3V 800 Vcc=3V 600 400 200 0 10000 20k 1000 Vcc=2.7V 4 8 12 16 Figure 58. Output power vs. power supply voltage 28 32 2200 F = 1kHz Cb = 1 μ F BW < 125 kHz Tamb = 25 ° C Output power at 10% THD + N (mW) Output power at 1% THD + N (mW) 24 Figure 59. Output power vs. power supply voltage 1800 1400 20 Load Resistance (Ω ) Frequency (Hz) 1600 THD+N = 1% F = 1kHz Cb = 1 μ F BW < 125kHz Tamb = 25 ° C Vcc=5.5V 1600 Output power (mW) Gain (dB) 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Figure 57. Output power vs. load resistance RL=4 Ω 1200 1000 800 RL=8 Ω 600 RL=16 Ω 400 200 RL=32 Ω 0 2.5 3.0 3.5 4.0 4.5 5.0 2000 1800 1600 F = 1kHz Cb = 1 μ F BW < 125 kHz Tamb = 25 ° C RL=4 Ω 1400 1200 1000 RL=8 Ω 800 600 RL=16 Ω 400 RL=32 Ω 200 0 2.5 5.5 3.0 3.5 Vcc (V) 4.0 4.5 5.0 5.5 Vcc (V) 1500 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 600 550 500 RL=4 Ω RL=8 Ω RL=16 Ω Vcc = 5V F = 1kHz THD+N < 1% 0 200 400 600 800 1000 1200 1400 1600 Output Power (mW) 18/34 Power Dissipation (mW) Power Dissipation (mW) Figure 60. Power dissipation vs. output power Figure 61. Power dissipation vs. output power RL=4 Ω 450 400 350 RL=8 Ω 300 250 200 RL=16 Ω 150 Vcc = 3.3V F = 1kHz THD+N < 1% 100 50 0 0 100 200 300 400 500 Output Power (mW) 600 700 TS4997 Electrical characteristics Figure 62. Power dissipation vs. output power Figure 63. Power derating curves Power Dissipation (mW) 350 RL=4 Ω 300 250 RL=8 Ω 200 150 RL=16 Ω 100 Vcc = 2.7V F = 1kHz THD+N < 1% 50 0 0 50 100 150 200 250 300 350 400 450 QFN16 Package Power Dissipation (W) 400 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 Mounted on 4-layer PCB with vias Mounted on 2-layer PCB with vias No Heat sink -AMR value 0 25 Table 8. 50 75 100 125 150 Ambiant Temperature (° C) Output Power (mW) Output noise, Tamb = 25°C Unweighted filter Conditions 3D effect level (20Hz to 20kHz) VCC = 2.7V to 5.5V A-weighted filter VCC = 2.7V to 5.5V Inputs floating OFF 10μVrms 6μVrms Inputs floating LOW 18μVrms 12μVrms Inputs floating MEDIUM 24μVrms 15μVrms Inputs floating HIGH 34μVrms 22μVrms Inputs grounded, G=6dB OFF 15μVrms 10μVrms Inputs grounded, G=6dB LOW 28μVrms 19μVrms Inputs grounded, G=6dB MEDIUM 36μVrms 24μVrms Inputs grounded, G=6dB HIGH 52μVrms 35μVrms Inputs grounded, G=12dB OFF 20μVrms 14μVrms Inputs grounded, G=12dB LOW 39μVrms 26μVrms Inputs grounded, G=12dB MEDIUM 50μVrms 33μVrms Inputs grounded, G=12dB HIGH 71μVrms 48μVrms 19/34 Application information TS4997 4 Application information 4.1 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, ● Virtually 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 R feed V O+ – V O- = ------------= ----------------------------------------------------- = 50kΩ -------------Diff input+ – Diff inputR IN R IN where RIN = RIN1 = RIN2 = RIN3 = RIN4 expressed in kΩ and Rfeed = 50kΩ (value of internal feedback resistors). 20/34 TS4997 Application information Due to the tolerance on the internal 50kΩ feedback resistors, the differential gain will be in the range (no tolerance on RIN): 40kΩ -------------- ≤A V ≤60kΩ -------------diff R IN R IN 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 V CC × R IN + 2 × V ic × 50kΩ V CC × R IN + 2 × V ic × R feed V ICM = --------------------------------------------------------------------------- = --------------------------------------------------------------------------- ( V ) 2 × ( R IN + R feed ) 2 × ( R IN + 50kΩ) with VCC in volts, RIN in kΩ and Diff input+ + Diff inputV ic = ------------------------------------------------------2 (V) The result of the calculation must be in the range: GND ≤ V ICM ≤ V CC – 1V Due to the +/-20% tolerance on the 50kΩ 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 CC × R IN + 2 × V ic × 60kΩ V CC × R IN + 2 × V ic × 40kΩ ------------------------------------------------------------------------- ≤V ICM ≤-------------------------------------------------------------------------(V) 2 × ( R IN + 40kΩ) 2 × ( R IN + 60kΩ) 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 = 50kΩ, calculated external resistors are RIN = Rfeed/AV = 25kΩ, VCC = 2.7V and Vic = 2.2V, which gives VICM = 1.92V. Taking into account the tolerance on the feedback resistors, with Rfeed = 40kΩ the common mode input voltage is VICM = 1.87V and with Rfeed = 60kΩ, 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 4.5 TS4997 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 CL = ----------------------------------------------- ( Hz ) 2 × π × R IN × C IN with RIN expressed in Ω and CIN expressed in F. So, for a desired -3dB cut-off frequency we can calculate CIN: 1 C IN = ------------------------------------------------ ( F ) 2 × π × R IN × F CL 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 Low -3dB Cut Off Frequency (Hz) Tamb=25 ° C Rin=6.2k Ω G~18dB 100 Rin=12k Ω G~12dB 10 0.1 Rin=24k Ω G~6dB 0.2 0.4 0.6 0.8 1 Input Capacitor Cin ( μ 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 Application information Table 9. 4.7 3D effect settings 3D effect level 3D0 3D1 OFF 0 0 LOW 0 1 MEDIUM 1 0 HIGH 1 1 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 out = V peak sinωt (V) and V out I out = ------------- (A) RL and V peak 2 P out = --------------------- (W) 2R L Therefore, the average current delivered by the supply voltage is: Equation 3 V peak I ccAVG = 2 ----------------- (A) πR 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 2V CC P diss = ---------------------- P out – P out ( W ) π RL 23/34 Application information TS4997 and the maximum value is obtained when: ∂Pdiss --------------------- = 0 ∂P out and its value is: Equation 5 Pdiss max = Note: 2 Vcc2 π2RL (W) 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 P out πV peak η = ------------------- = -------------------P supply 4Vcc The maximum theoretical value is reached when Vpeak = VCC, so: η = π----- = 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 2V CC TotalP diss = 2 × P diss1 = ---------------------- P out – 2P out ( W ) π RL The maximum die temperature allowable for the TS4997 is 150°C. In case of overheating, a thermal shutdown protection set to 150°C, puts the TS4997 in standby until the temperature of the die is reduced by about 5°C. 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=8Ω, RTHJAQFN16=85°C/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 Application information Tamb is calculated as follows: Equation 7 T amb = 150° C – R TJHA × TotalPdissmax Therefore, the maximum allowable value for Tamb is: Tamb = 150 - 85 x 2 x 1.266=42.4°C If a 4-layer PCB with vias is used, RTHJAQFN16 = 45°C/W and the maximum allowable value for Tamb in this case is: Tamb = 150 - 45 x 2 x 1.266 = 93°C 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 1µF, one can expect THD+N performance similar to that shown in the datasheet. In the high frequency region, if CS is lower than 1µF, then THD+N increases and disturbances on the power supply rail are less filtered. On the other hand, if CS is greater than 1µF, 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=1µF. 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 1µF, 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 Tamb=25 ° C Startup Time (ms) 90 Vcc=2.7V 80 Vcc=3.3V 70 60 Vcc=5V 50 40 30 0.0 26/34 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Bypass Capacitor Cb (μ F) 4.0 4.5 TS4997 4.11 Application information 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. 27/34 Application information TS4997 Figure 67. Typical single-ended input application 330nF 24k Cin2 Rin2 Diff. input R- 3D1 Control Vcc P1 330nF 24k Cin3 Rin3 330nF 24k 1 LI N- 2 LI N+ 4 RIN- 3 RIN+ Rin4 330nF 24k - LOUT- 12 + LOUT+ 11 - ROUT- 9 + ROUT+ 10 Left Speaker LEFT P2 Cin4 3D1 Rin1 3D0 Cin1 1uF 13 TS4997 - QFN16 Diff. input L- Cs 15 16 3D0 Control VCC 3D EFFECT 8 Ohms Right Speaker RIGHT 8 Ohms Bypass STBYR 7 STBYL Control STBYL GND 6 1uF Cb 5 GND STBY 8 BIAS STBYR Control 14 The component calculations remain the same for the gain. In single-ended input configuration, the formula is: V O+ – V OR feed 50kΩAv SE = -------------------------- = ------------- = ------------Ve R IN R IN with RIN expressed in kΩ. 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. 28/34 TS4997 Application information Figure 68. PSRR measurement 3D1 Control 13 TS4997 - QFN16 Rin1 3D1 Vcc 3D0 Cin1 Vcc 15 16 3D0 Control Vripple 4.7uF Cin2 1 LI N- 2 LI N+ 4 RIN- 3 RIN+ Rin2 Rin3 12 + LOUT+ 11 - ROUT- 9 + ROUT+ 10 RL 8Ohms 3D EFFECT RL 8Ohms RIGHT 4.7uF Cin4 LOUT- LEFT 4.7uF Cin3 - Rin4 Bypass 4.7uF STBYR 7 STBYL Control STBYL GND 6 1uF Cb 5 GND STBY 8 BIAS STBYR Control 14 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: RMS ( Output ) PSRR = 20 × Log --------------------------------- ( dB ) RMS ( Vripple ) RMS is an rms selective measurement. 29/34 QFN16 package information 5 TS4997 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 LIN- 1 12 LOUT- LIN+ 2 11 LOUT+ RIN+ 3 10 ROUT+ RIN- 4 9 ROUT- 5 6 7 8 GND GND STBYR STBYL 30/34 TS4997 QFN16 package information Figure 71. QFN16 4x4mm Dimensions Millimeters (mm) Ref Min Typ Max 0.8 0.9 1.0 A1 0.02 0.05 A3 0.20 A * * The Exposed Pad is connected to Ground. b 0.18 0.25 0.30 D 3.85 4.0 4.15 D2 2.1 E 3.85 E2 2.1 2.6 4.0 4.15 2.6 e 0.65 K 0.2 L 0.30 r 0.11 0.40 0.50 Figure 72. Footprint soldering pad Footprint data Ref mm A 4.2 B 4.2 C 0.65 D 0.35 E 0.65 F 2.70 31/34 Ordering information 6 TS4997 Ordering information Table 10. Order codes Part number TS4997IQT 32/34 Temperature range Package Packaging Marking -40°C, +85°C QFN16 4x4mm Tape & reel Q997 TS4997 7 Revision history Revision history Date Revision Changes 10-Jan-2007 1 Preliminary data. 20-Feb-2007 2 First release. 33/34 TS4997 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. 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