TS4994 1W differential input/output audio power amplifier with selectable standby Features Pin connections (top view) Differential inputs Near-zero pop & click 100dB PSRR @ 217Hz with grounded inputs Operating range from VCC = 2.5V to 5.5V 1W rail-to-rail output power @ VCC = 5V, THD = 1%, F = 1kHz, with 8 load 90dB CMRR @ 217Hz Ultra-low consumption in standby mode (10nA) Selectable standby mode (active low or active high) Ultra fast startup time: 15ms typ. Available in DFN10 3x3 (0.5mm pitch) & MiniSO-8 All lead-free packages TS4994IQT - DFN10 An external standby mode control reduces the supply current to less than 10nA. An STBY MODE pin allows the standby to be active HIGH or LOW (except in the MiniSO-8 version). An internal thermal shutdown protection is also provided, making the device capable of sustaining short-circuits. The device is equipped with common mode feedback circuitry allowing outputs to be always 1 10 VO+ VIN - 2 9 VDD STBY MODE 3 8 N/C VIN + 4 7 GND BYPASS 5 6 VO- TS4994IST - MiniSO-8 Description The TS4994 is an audio power amplifier capable of delivering 1W of continuous RMS output power into an 8 load @ 5V. Due to its differential inputs, it exhibits outstanding noise immunity. STBY STBY 1 8 VIN- 2 7 Vcc VO+ VIN+ 3 6 GND BYPASS 4 5 VO- biased at VCC/2 regardless of the input common mode voltage. The TS4994 is designed for high quality audio applications such as mobile phones and requires few external components. Applications Mobile phones (cellular / cordless) Laptop / notebook computers PDAs Portable audio devices Order codes Part number Temperature range TS4994IQT Package DFN10 -40C to +85C TS4994IST December 2006 Packing Marking K994 Tape & reel MiniSO-8 Rev 6 K994 1/35 www.st.com 35 Contents TS4994 Contents 1 Application component information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Absolute maximum ratings and operating conditions . . . . . . . . . . . . . 5 3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 5 6 2/35 4.1 Differential configuration principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 4.2 Gain in typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 4.3 Common mode feedback loop limitations . . . . . . . . . . . . . . . . . . . . . . . . . 21 4.4 Low and high frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 4.5 Calculating the influence of mismatching on PSRR performance . . . . . . 23 4.6 CMRR performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 4.7 Power dissipation and efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 4.8 Decoupling of the circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 4.9 Wake-up time: tWU 4.10 Shutdown time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.11 Pop performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.12 Single-ended input configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.13 Demoboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 5.1 DFN10 package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 5.2 MiniSO-8 package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 TS4994 Application component information Components Functional description Cs Supply bypass capacitor that provides power supply filtering. Cb Bypass capacitor that provides half supply filtering. Rfeed Feedback resistor that sets the closed loop gain in conjunction with Rin AV = closed loop gain = Rfeed/Rin. Rin Inverting input resistor that sets the closed loop gain in conjunction with Rfeed. Cin Optional input capacitor making a high pass filter together with Rin. (FCL = 1/(2RinCin). Figure 1. Typical application, DFN10 version VCC + Rfeed1 20k 9 Cs 1u GND VCC Cin1 + Diff. input - 220nF 20k Cin2 Rin2 + GND Rin1 220nF 20k Diff. Input + Optional + 1 Application component information 2 Vin- - 4 Vin+ + Vo+ 10 Vo6 8 Ohms 5 Bypass Bias Cb 1u Standby Mode Stdby GND 1 7 GND 3 GND TS4994IQ Rfeed2 20k GND VCC GND VCC 3/35 Application component information Figure 2. TS4994 Typical application, MiniSO-8 version VCC + Rfeed1 20k 7 Cs 1u GND VCC Cin1 + Diff. input - 220nF 20k Cin2 Rin2 + GND Rin1 2 Vin- - 3 Vin+ + Vo+ 8 Vo5 220nF 20k 8 Ohms 4 Bypass + Diff. Input + Optional Bias Cb 1u Standby Stdby GND 1 6 GND GND TS4994IS Rfeed2 20k GND VCC 4/35 TS4994 Absolute maximum ratings and operating conditions 2 Absolute maximum ratings and operating conditions Table 1. Absolute maximum ratings Symbol VCC Vi Parameter Supply voltage (1) Input voltage (2) Value Unit 6 V GND to VCC V Toper Operating free air temperature range -40 to + 85 C Tstg Storage temperature -65 to +150 C 150 C 120 215 C/W internally limited W 2 kV Machine model 200 V Latch-up immunity 200 mA Lead temperature (soldering, 10sec) 260 C Value Unit Tj Maximum junction temperature Rthja Thermal resistance junction to ambient DFN10 MiniSO-8 Pdiss Power dissipation (3) Human body model ESD 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. The device is protected by a thermal shutdown active at 150C. Table 2. Operating conditions Symbol Parameter VCC Supply voltage 2.5 to 5.5 V VSM Standby mode voltage input: Standby active LOW Standby active HIGH VSM=GND VSM=VCC V 1.5 VSTBY VCC GND VSTBY 0.4 (1) V VSTBY Standby voltage input: Device ON (VSM = GND) or device OFF (VSM = VCC) Device OFF (VSM = GND) or device ON (VSM = VCC) TSD Thermal shutdown temperature 150 C RL Load resistor 8 Thermal resistance junction to ambient DFN10 (2) MiniSO-8 80 190 C/W Rthja 1. The minimum current consumption (ISTBY) is guaranteed when VSTBY = GND or VCC (i.e. supply rails) for the whole temperature range. 2. When mounted on a 4-layer PCB. 5/35 Electrical characteristics TS4994 3 Electrical characteristics Table 3. Electrical characteristics for VCC = +5V, GND = 0V, Tamb = 25C (unless otherwise specified) Symbol ICC ISTBY Voo Parameter Min. Typ. Max. Unit Supply current No input signal, no load 4 7 mA Standby current No input signal, VSTBY = VSM = GND, RL = 8 No input signal, VSTBY = VSM = VCC, RL = 8 10 1000 nA Differential output offset voltage No input signal, RL = 8 0.1 10 mV VCC - 0.9 V VICM Input common mode voltage CMRR -60dB 0.6 Pout Output power THD = 1% Max, F= 1kHz, RL = 8 0.8 1 W THD + N Total harmonic distortion + noise Pout = 850mW rms, AV = 1, 20Hz F 20kHz, RL = 8 0.5 % PSRRIG Power supply rejection ratio with inputs grounded(1) F = 217Hz, R = 8, AV = 1, Cin = 4.7F, Cb =1F Vripple = 200mVPP 100 dB CMRR Common mode rejection ratio F = 217Hz, RL = 8, AV = 1, Cin = 4.7F, Cb =1F Vic = 200mVPP 90 dB SNR Signal-to-noise ratio (A-weighted filter, AV = 2.5) RL = 8, THD +N < 0.7%, 20Hz F 20kHz 100 dB GBP Gain bandwidth product RL = 8 2 MHz VN Output voltage noise, 20Hz F 20kHz, RL = 8 Unweighted, AV = 1 A-weighted, AV = 1 Unweighted, AV = 2.5 A-weighted, AV = 2.5 Unweighted, AV = 7.5 A-weighted, AV = 7.5 Unweighted, Standby A-weighted, Standby tWU Wake-up time(2) Cb =1F 6 5.5 12 10.5 33 28 1.5 1 15 1. Dynamic measurements - 20*log(rms(Vout)/rms (Vripple)). Vripple is the super-imposed sinus signal relative to VCC. 2. Transition time from standby mode to fully operational amplifier. 6/35 VRMS ms TS4994 Table 4. Electrical characteristics Electrical characteristics for VCC = +3.3V (all electrical values are guaranteed with correlation measurements at 2.6V and 5V), GND = 0V, Tamb = 25C (unless otherwise specified) Symbol ICC ISTBY Voo Parameter Min. Typ. Max. Unit Supply current no input signal, no load 3 7 mA Standby current No input signal, VSTBY = VSM = GND, RL = 8 No input signal, VSTBY = VSM = VCC, RL = 8 10 1000 nA Differential output offset voltage No input signal, RL = 8 0.1 10 mV VCC - 0.9 V VICM Input common mode voltage CMRR -60dB 0.6 Pout Output power THD = 1% max, F= 1kHz, RL = 8 300 380 mW THD + N Total harmonic distortion + noise Pout = 300mW rms, AV = 1, 20Hz F 20kHz, RL = 8 0.5 % PSRRIG Power supply rejection ratio with inputs grounded(1) F = 217Hz, R = 8, AV = 1, Cin = 4.7F, Cb =1F Vripple = 200mVPP 100 dB CMRR Common mode rejection ratio F = 217Hz, RL = 8, AV = 1, Cin = 4.7F, Cb =1F Vic = 200mVPP 90 dB SNR Signal-to-noise ratio (A-weighted filter, AV = 2.5) RL = 8, THD +N < 0.7%, 20Hz F 20kHz 100 dB GBP Gain bandwidth product RL = 8 2 MHz VN Output voltage noise, 20Hz F 20kHz, RL = 8 Unweighted, AV = 1 A-weighted, AV = 1 Unweighted, AV = 2.5 A-weighted, AV = 2.5 Unweighted, AV = 7.5 A-weighted, AV = 7.5 Unweighted, Standby A-weighted, Standby tWU Wake-up time(2) Cb =1F 6 5.5 12 10.5 33 28 1.5 1 15 VRMS ms 1. Dynamic measurements - 20*log(rms(Vout)/rms (Vripple)). Vripple is the super-imposed sinus signal relative to VCC. 2. Transition time from standby mode to fully operational amplifier. 7/35 Electrical characteristics Table 5. Electrical characteristics for VCC = +2.6V, GND = 0V, Tamb = 25C (unless otherwise specified) Symbol ICC ISTBY Voo TS4994 Parameter Min. Typ. Max. Unit Supply current No input signal, no load 3 7 mA Standby current No input signal, VSTBY = VSM = GND, RL = 8 No input signal, VSTBY = VSM = VCC, RL = 8 10 1000 nA Differential output offset voltage No input signal, RL = 8 0.1 10 mV VCC- 0.9 V VICM Input common mode voltage CMRR -60dB 0.6 Pout Output power THD = 1% max, F= 1kHz, RL = 8 200 250 mW THD + N Total harmonic distortion + noise Pout = 225mW rms, AV = 1, 20Hz F 20kHz, RL = 8 0.5 % PSRRIG Power supply rejection ratio with inputs grounded(1) F = 217Hz, R = 8, AV = 1, Cin = 4.7F, Cb =1F Vripple = 200mVPP 100 dB CMRR Common mode rejection ratio F = 217Hz, RL = 8, AV = 1, Cin = 4.7F, Cb =1F Vic = 200mVPP 90 dB SNR Signal-to-noise ratio (A-weighted filter, AV = 2.5) RL = 8, THD +N < 0.7%, 20Hz F 20kHz 100 dB GBP Gain bandwidth product RL = 8 2 MHz VN Output voltage noise, 20Hz F 20kHz, RL = 8 Unweighted, AV = 1 A-weighted, AV = 1 Unweighted, AV = 2.5 A-weighted, AV = 2.5 Unweighted, AV = 7.5 A-weighted, AV = 7.5 Unweighted, Standby A-weighted, Standby tWU Wake-up time(2) Cb =1F 6 5.5 12 10.5 33 28 1.5 1 15 1. Dynamic measurements - 20*log(rms(Vout)/rms (Vripple)). Vripple is the super-imposed sinus signal relative to VCC. 2. Transition time from standby mode to fully operational amplifier. 8/35 VRMS ms TS4994 Electrical characteristics Current consumption vs. power supply voltage Figure 4. 4.0 4.0 No load 3.5 Tamb=25C 3.5 Current Consumption (mA) Current Consumption (mA) Figure 3. 3.0 2.5 2.0 1.5 1.0 0.5 0.0 Current consumption vs. standby voltage 3.0 Standby mode=0V 2.5 Standby mode=5V 2.0 1.5 1.0 Vcc = 5V No load Tamb=25C 0.5 0 1 2 3 4 0.0 5 0 1 2 Power Supply Voltage (V) Current consumption vs. power supply voltage Figure 6. 3.5 3.0 3.0 2.5 2.5 Standby mode=0V Standby mode=3.3V 2.0 1.5 1.0 Vcc = 3.3V No load Tamb=25C 0.5 0.0 0.0 0.6 1.2 1.8 2.4 Current Consumption (mA) Current Consumption (mA) Figure 5. 4 5 Standby mode=0V Standby mode=2.6V 2.0 1.5 1.0 Vcc = 2.6V No load Tamb=25C 0.5 0.0 0.0 3.0 Current consumption vs. standby voltage 0.6 Standby Voltage (V) Figure 7. 3 Standby Voltage (V) 1.2 1.8 2.4 Standby Voltage (V) Differential DC output voltage vs. common mode input voltage Figure 8. Power dissipation vs. output power 1000 Av = 1 Tamb = 25C Voo (mV) Power Dissipation (W) 0.6 100 Vcc=3.3V Vcc=2.5V 10 Vcc=5V 1 RL=8 0.4 0.2 RL=16 0.1 0.01 0.0 Vcc=5V F=1kHz THD+N<1% 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Common Mode Input Voltage (V) 4.5 5.0 0.0 0.0 0.2 0.4 0.6 Output Power (W) 0.8 1.0 9/35 Electrical characteristics Figure 9. TS4994 Power dissipation vs. output power Figure 10. Power dissipation vs. output power 0.20 0.3 Power Dissipation (W) Power Dissipation (W) Vcc=2.6V F=1kHz THD+N<1% RL=8 0.2 0.1 RL=16 0.0 0.0 0.1 Vcc=3.3V F=1kHz THD+N<1% 0.2 0.3 Output Power (W) RL=8 0.10 0.05 RL=16 0.00 0.0 0.4 0.1 0.2 Figure 12. Output power vs. power supply voltage 1.0 1.50 Cb = 1F F = 1kHz BW < 125kHz Tamb = 25C 8 Output power @ 10% THD + N (W) 0.8 16 0.6 0.4 0.2 32 0.0 2.5 3.0 3.5 4.0 4.5 1.25 1.00 8 16 0.75 0.50 0.25 0.00 2.5 5.0 Cb = 1F F = 1kHz BW < 125kHz Tamb = 25C 32 3.0 3.5 1.0 Output power (W) 0.8 THD+N=1% Cb = 1 F F = 1kHz BW < 125kHz Tamb = 25C Vcc=5V Vcc=4.5V 0.6 Vcc=4V 0.4 0.2 Vcc=3.5V Vcc=3V 10/35 8 12 Vcc=2.5V 16 20 24 Load Resistance 32 5.0 1.5 with 4 layers PCB 1.0 0.5 AMR Value 0.0 28 4.5 Figure 14. Power derating curves DFN10 Package Power Dissipation (W) Figure 13. Output power vs. load resistance 4.0 Vcc (V) Vcc (V) 0.0 0.3 Output Power (W) Figure 11. Output power vs. power supply voltage Output power @ 1% THD + N (W) 0.15 0 25 50 75 Ambiant Temperature ( C) 100 125 TS4994 Electrical characteristics Figure 16. Open loop gain vs. frequency 0.6 0 60 Nominal Value Gain AMR Value 0.2 -80 20 Phase -120 0 25 50 75 100 -40 0.1 125 1 10 100 1000 Figure 18. Open loop gain vs. frequency 0 0 60 60 Gain Gain -40 -40 Phase -120 0 -160 Vcc = 3.3V ZL = 8 + 500pF Tamb = 25C 1 10 100 1000 -80 20 Phase -120 0 -40 0.1 -200 10000 -160 Vcc = 2.6V ZL = 8 + 500pF Tamb = 25C -20 1 10 100 Figure 19. Closed loop gain vs. frequency Figure 20. Closed loop gain vs. frequency 0 10 0 10 Phase Phase -40 -20 -120 -40 0.1 Vcc = 5V Av = 1 ZL = 8 + 500pF Tamb = 25C 1 -160 10 100 Frequency (kHz) 1000 -200 10000 Gain (dB) -80 0 Phase () Gain (dB) Gain -10 -30 -200 10000 Frequency (kHz) Frequency (kHz) 0 1000 Gain -40 -10 -80 -20 -120 -30 -40 0.1 Vcc = 3.3V Av = 1 ZL = 8 + 500pF Tamb = 25C 1 Phase () -40 0.1 Phase () -80 20 Gain (dB) 40 Phase () Gain (dB) 40 -20 -200 10000 Frequency (kHz) Ambiant Temperature ( C) Figure 17. Open loop gain vs. frequency -160 Vcc = 5V ZL = 8 + 500pF Tamb = 25C -20 0 Phase () 0.4 0.0 -40 40 Gain (dB) MiniSO8 Package Power Dissipation (W) Figure 15. Power derating curves -160 10 100 1000 -200 10000 Frequency (kHz) 11/35 Electrical characteristics TS4994 Figure 21. Closed loop gain vs. frequency Figure 22. PSRR vs. frequency 0 0 10 Phase Gain -30 -120 -20 PSRR (dB) -80 -10 Vcc = 5V Vripple = 200mVpp Inputs = Grounded Av = 1, Cin = 4.7F RL 8 Tamb = 25C -20 -40 Phase () 0 Gain (dB) -10 -40 -50 Cb=0.1F -60 Cb=0.47F -70 Cb=1F -80 Vcc = 2.6V Av = 1 ZL = 8 + 500pF Tamb = 25C -30 -40 0.1 1 -90 -160 -100 10 100 1000 -120 Frequency (kHz) Figure 23. PSRR vs. frequency PSRR (dB) -40 -50 -30 Cb=0.1F -60 Cb=0.47F -70 Cb=1F -80 -40 -50 10000 20k Cb=0.1F -60 Cb=0.47F -70 Cb=1F -80 -90 -90 -100 -100 Cb=0 -110 Cb=0 -110 20 100 1000 Frequency (Hz) -120 10000 20k Figure 25. PSRR vs. frequency 20 100 1000 Frequency (Hz) 10000 20k Figure 26. PSRR vs. frequency 0 0 -10 Vcc = 5V Vripple = 200mVpp Inputs = Grounded Av = 2.5, Cin = 4.7F RL 8 Tamb = 25C -20 -30 -40 -50 -30 Cb=0.1F Cb=0.47F -60 -70 Cb=1F -80 Vcc = 3.3V Vripple = 200mVpp Inputs = Grounded Av = 2.5, Cin = 4.7F RL 8 Tamb = 25C -20 PSRR (dB) -10 PSRR (dB) 1000 Frequency (Hz) Vcc = 2.6V Vripple = 200mVpp Inputs = Grounded Av = 1, Cin = 4.7F RL 8 Tamb = 25C -20 PSRR (dB) -30 -40 -50 Cb=0.1F Cb=0.47F -60 -70 Cb=1F -80 -90 -90 Cb=0 -100 -110 12/35 100 0 -10 Vcc = 3.3V Vripple = 200mVpp Inputs = Grounded Av = 1, Cin = 4.7F RL 8 Tamb = 25C -20 -120 20 Figure 24. PSRR vs. frequency 0 -10 -120 Cb=0 -110 -200 10000 Cb=0 -100 -110 20 100 1000 Frequency (Hz) 10000 20k -120 20 100 1000 Frequency (Hz) 10000 20k TS4994 Electrical characteristics Figure 27. PSRR vs. frequency Figure 28. PSRR vs. frequency 0 0 -20 -30 -40 PSRR (dB) -10 Vcc = 2.6V Vripple = 200mVpp Inputs = Grounded Av = 2.5, Cin = 4.7F RL 8 Tamb = 25C -50 -30 Cb=0.1F Cb=0.47F -60 -70 Cb=1F -80 -40 -50 Cb=1F -90 Cb=0 -100 -110 Cb=0 -110 20 100 -120 10000 20k 1000 Frequency (Hz) Figure 29. PSRR vs. frequency 20 100 10000 20k 1000 Frequency (Hz) Figure 30. PSRR vs. frequency 0 0 -10 Vcc = 3.3V Vripple = 200mVpp Inputs = Floating Rfeed = 20k RL 8 Tamb = 25C -20 -30 -40 -50 -30 Cb=0.1F -60 Cb=0.47F -70 Cb=1F -80 Vcc = 2.6V Vripple = 200mVpp Inputs = Floating Rfeed = 20k RL 8 Tamb = 25C -20 -40 PSRR (dB) -10 PSRR (dB) Cb=0.47F -70 -80 -100 -50 Cb=0.1F -60 Cb=0.47F -70 Cb=1F -80 -90 -90 -100 -100 Cb=0 -110 -120 Cb=0.1F -60 -90 -120 Vcc = 5V Vripple = 200mVpp Inputs = Floating Rfeed = 20k RL 8 Tamb = 25C -20 PSRR (dB) -10 Cb=0 -110 20 100 10000 20k 1000 Frequency (Hz) Figure 31. PSRR vs. common mode input voltage -120 20 100 10000 20k 1000 Frequency (Hz) Figure 32. PSRR vs. common mode input voltage 0 -40 -20 PSRR(dB) -20 PSRR(dB) 0 Vcc = 5V Vripple = 200mVpp Inputs Grounded F = 217Hz Av = 1 RL 8 Tamb = 25C Cb=1F Cb=0.47F Cb=0.1F -60 -40 Vcc = 3.3V Vripple = 200mVpp Inputs Grounded F = 217Hz Av = 1 RL 8 Tamb = 25C -60 Cb=0 Cb=0 -80 -80 -100 -100 0 1 2 3 4 Common Mode Input Voltage (V) 5 0.0 Cb=1F Cb=0.47F Cb=0.1F 0.6 1.2 1.8 2.4 3.0 Common Mode Input Voltage (V) 13/35 Electrical characteristics TS4994 Figure 33. PSRR vs. common mode input voltage PSRR(dB) -20 -40 0 Vcc = 2.5V Vripple = 200mVpp Inputs Grounded F = 217Hz Av = 1 RL 8 Tamb = 25C -60 -10 -30 Cb=1F Cb=0.47F Cb=0.1F Cb=0 -80 -40 -50 -60 -70 -90 -100 -110 0.5 1.0 1.5 2.0 -120 2.5 20 100 Common Mode Input Voltage (V) Figure 35. CMRR vs. frequency -40 -50 Vcc = 2.6V Vic = 200mVpp Av = 1, Cin = 470F RL 8 Tamb = 25C -20 -30 Cb=1F Cb=0.47F Cb=0.1F Cb=0 -60 CMRR (dB) CMRR (dB) -30 -70 -80 -40 Cb=1F Cb=0.47F Cb=0.1F Cb=0 -50 -60 -70 -80 -90 -90 -100 -100 -110 -110 20 100 1000 Frequency (Hz) -120 10000 20k Figure 37. CMRR vs. frequency 20 100 1000 Frequency (Hz) 10000 20k Figure 38. CMRR vs. frequency 0 0 Vcc = 5V Vic = 200mVpp Av = 2.5, Cin = 470F RL 8 Tamb = 25C -20 -30 -40 -20 -30 Cb=1F Cb=0.47F Cb=0.1F Cb=0 -50 -60 -70 Vcc = 3.3V Vic = 200mVpp Av = 2.5, Cin = 470F RL 8 Tamb = 25C -10 CMRR (dB) -10 CMRR (dB) 10000 20k 0 -10 Vcc = 3.3V Vic = 200mVpp Av = 1, Cin = 470F RL 8 Tamb = 25C -20 -40 Cb=1F Cb=0.47F Cb=0.1F Cb=0 -50 -60 -70 -80 -80 -90 -90 -100 -100 14/35 1000 Frequency (Hz) Figure 36. CMRR vs. frequency 0 -10 -120 Cb=1F Cb=0.47F Cb=0.1F Cb=0 -80 -100 0.0 Vcc = 5V Vic = 200mVpp Av = 1, Cin = 470F RL 8 Tamb = 25C -20 CMRR (dB) 0 Figure 34. CMRR vs. frequency 20 100 1000 Frequency (Hz) 10000 20k 20 100 1000 Frequency (Hz) 10000 20k TS4994 Electrical characteristics Figure 39. CMRR vs. frequency Figure 40. CMRR vs. common mode input voltage 0 -30 -40 Vcc=3.3V -20 CMRR(dB) -20 CMRR (dB) 0 Vcc = 2.6V Vic = 200mVpp Av = 2.5, Cin = 470F RL 8 Tamb = 25C -10 Cb=1F Cb=0.47F Cb=0.1F Cb=0 -50 -60 -70 Vcc=2.5V Vic = 200mVpp F = 217Hz Av = 1, Cb = 1F RL 8 Tamb = 25C -40 -60 -80 -80 -100 -90 -100 20 100 0.0 10000 20k 1000 Frequency (Hz) Vcc=5V 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Common Mode Input Voltage (V) Figure 41. CMRR vs. common mode input voltage Figure 42. THD+N vs. output power 10 0 Vcc=3.3V Vcc=2.5V THD + N (%) CMRR(dB) -20 Vic = 200mVpp F = 217Hz Av = 1, Cb = 0 RL 8 Tamb = 25C -40 -60 -80 Vcc=3.3V Vcc=5V 0.1 Vcc=5V 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 1E-3 1E-3 Common Mode Input Voltage (V) Figure 43. THD+N vs. output power 1 10 Vcc=2.6V Vcc=3.3V THD + N (%) RL = 8 F = 20Hz Av = 2.5 1 Cb = 1F BW < 125kHz Tamb = 25C 0.01 0.1 Output Power (W) Figure 44. THD+N vs. output power 10 THD + N (%) Vcc=2.6V 0.01 -100 0.0 RL = 8 F = 20Hz Av = 1 1 Cb = 1F BW < 125kHz Tamb = 25C Vcc=5V 0.1 RL = 8 F = 20Hz Av = 7.5 1 Cb = 1F BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=3.3V Vcc=5V 0.1 0.01 0.01 1E-3 1E-3 0.01 0.1 Output Power (W) 1 1E-3 0.01 0.1 Output Power (W) 1 15/35 Electrical characteristics TS4994 Figure 45. THD+N vs. output power Figure 46. THD+N vs. output power 10 10 Vcc=2.6V Vcc=3.3V Vcc=5V 0.1 0.01 1E-3 RL = 8 F = 1kHz Av = 2.5 1 Cb = 1F BW < 125kHz Tamb = 25C THD + N (%) THD + N (%) RL = 8 F = 1kHz Av = 1 1 Cb = 1F BW < 125kHz Tamb = 25C Vcc=5V 0.1 0.01 0.1 Output Power (W) 1 1E-3 0.01 0.1 Output Power (W) 1 Figure 48. THD+N vs. output power 10 10 Vcc=2.6V Vcc=3.3V THD + N (%) THD + N (%) Vcc=3.3V 0.01 Figure 47. THD+N vs. output power RL = 8 F = 1kHz Av = 7.5 1 Cb = 1F BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=5V 0.1 RL = 8 F = 20kHz Av = 1 Cb = 1F BW < 125kHz 1 Tamb = 25C Vcc=2.6V Vcc=3.3V Vcc=5V 0.1 0.01 1E-3 0.01 0.1 Output Power (W) 1 Figure 49. THD+N vs. output power 1E-3 10 RL = 8 F = 20kHz Av = 7.5 Cb = 1F BW < 125kHz Tamb = 25C Vcc=2.6V THD + N (%) THD + N (%) 1 Figure 50. THD+N vs. output power 10 RL = 8 F = 20kHz Av = 2.5 Cb = 1F BW < 125kHz 1 Tamb = 25C 0.01 0.1 Output Power (W) Vcc=3.3V Vcc=5V 1 Vcc=2.6V Vcc=3.3V Vcc=5V 0.1 1E-3 16/35 0.01 0.1 Output Power (W) 1 0.1 1E-3 0.01 0.1 Output Power (W) 1 TS4994 Electrical characteristics Figure 51. THD+N vs. output power Figure 52. THD+N vs. output power 10 RL = 16 F = 20Hz 1 Av = 1 Cb = 1F BW < 125kHz Tamb = 25C 0.1 RL = 16 F = 20Hz 1 Av = 7.5 Cb = 1F BW < 125kHz Tamb = 25C 0.1 Vcc=2.6V Vcc=3.3V THD + N (%) THD + N (%) 10 Vcc=5V Vcc=2.6V Vcc=3.3V Vcc=5V 0.01 0.01 1E-3 1E-3 0.01 0.1 Output Power (W) 1 Figure 53. THD+N vs. output power 1E-3 1E-3 10 RL = 16 F = 1kHz Av = 7.5 1 Cb = 1F BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=3.3V THD + N (%) THD + N (%) 1 Figure 54. THD+N vs. output power 10 RL = 16 F = 1kHz 1 Av = 1 Cb = 1F BW < 125kHz Tamb = 25C 0.1 0.01 0.1 Output Power (W) Vcc=5V Vcc=2.6V Vcc=3.3V Vcc=5V 0.1 0.01 0.01 1E-3 1E-3 0.01 0.1 Output Power (W) 1 Figure 55. THD+N vs. output power 1E-3 10 RL = 16 F = 20kHz Av = 7.5 Cb = 1F BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=3.3V THD + N (%) THD + N (%) 1 Figure 56. THD+N vs. output power 10 RL = 16 F = 20kHz Av = 1 Cb = 1F 1 BW < 125kHz Tamb = 25C 0.01 0.1 Output Power (W) Vcc=5V Vcc=2.6V Vcc=3.3V Vcc=5V 1 0.1 0.01 1E-3 0.01 0.1 Output Power (W) 1 0.1 1E-3 0.01 0.1 Output Power (W) 1 17/35 Electrical characteristics TS4994 Figure 57. THD+N vs. output power Figure 58. THD+N vs. output power 10 10 F=20kHz THD + N (%) THD + N (%) 1 RL = 8 Vcc = 5V Av = 1 Cb = 0 BW < 125kHz Tamb = 25C F=1kHz 0.1 RL = 8 Vcc = 2.6V Av = 1, Cb = 0 1 BW < 125kHz Tamb = 25C F=20kHz F=1kHz 0.1 F=20Hz 0.01 0.01 F=20Hz 1E-3 0.01 0.1 Output Power (W) 1E-3 1E-3 1 Figure 59. THD+N vs. output power 10 RL = 16 Vcc = 5V Av = 1, Cb = 0 1 BW < 125kHz Tamb = 25C THD + N (%) F=20kHz F=1kHz 0.1 RL = 16 Vcc = 2.6V Av = 1, Cb = 0 1 BW < 125kHz Tamb = 25C F=1kHz F=20Hz 0.01 1E-3 1E-3 0.01 0.1 Output Power (W) 1E-3 1E-3 1 Figure 61. THD+N vs. frequency 0.1 10 Vcc=2.6V, Po=225mW THD + N (%) RL = 8 Av = 1 Cb = 1F 1 Bw < 125kHz Tamb = 25C THD + N (%) 0.01 Output Power (W) Figure 62. THD+N vs. frequency 10 0.1 0.01 RL = 8 Av = 1 Cb = 0 1 Bw < 125kHz Tamb = 25C Vcc=2.6V, Po=225mW 0.1 0.01 Vcc=5V, Po=850mW 18/35 F=20kHz 0.1 F=20Hz 0.01 1E-3 0.1 Figure 60. THD+N vs. output power 10 THD + N (%) 0.01 Output Power (W) 20 100 1000 Frequency (Hz) 10000 20k Vcc=5V, Po=850mW 1E-3 20 100 1000 Frequency (Hz) 10000 20k TS4994 Electrical characteristics Figure 63. THD+N vs. frequency Figure 64. THD+N vs. frequency 10 RL = 8 Av = 7.5 Cb = 1F Bw < 125kHz 1 Tamb = 25C Vcc=2.6V, Po=225mW THD + N (%) THD + N (%) 10 0.1 RL = 8 Av = 7.5 Cb = 0 Bw < 125kHz 1 Tamb = 25C Vcc=2.6V, Po=225mW 0.1 Vcc=5V, Po=850mW 0.01 20 100 Vcc=5V, Po=850mW 0.01 10000 20k 1000 Frequency (Hz) Figure 65. THD+N vs. frequency 100 10 RL = 16 Av = 1 Cb = 1F 1 Bw < 125kHz Tamb = 25C RL = 16 Av = 7.5 Cb = 1F 1 Bw < 125kHz Tamb = 25C THD + N (%) Vcc=2.6V, Po=155mW 0.1 Vcc=2.6V, Po=155mW 0.1 0.01 0.01 Vcc=5V, Po=600mW 1E-3 10000 20k 1000 Frequency (Hz) Figure 66. THD+N vs. frequency 10 THD + N (%) 20 20 100 Vcc=5V, Po=600mW 10000 20k 1000 Frequency (Hz) 1E-3 20 100 10000 20k 1000 Frequency (Hz) Figure 67. SNR vs. power supply voltage with Figure 68. SNR vs. power supply voltage with unweighted filter A-weighted filter 110 110 105 Signal to Noise Ratio (dB) Signal to Noise Ratio (dB) RL=16 100 RL=8 95 90 Av = 2.5 85 Cb = 1F THD+N < 0.7% Tamb = 25C 80 2.5 3.0 3.5 4.0 Power Supply Voltage (V) 4.5 5.0 RL=16 105 100 RL=8 95 90 Av = 2.5 85 Cb = 1F THD+N < 0.7% Tamb = 25C 80 2.5 3.0 3.5 4.0 4.5 5.0 Power Supply Voltage (V) 19/35 Electrical characteristics TS4994 Figure 69. Startup time vs. bypass capacitor 20 Tamb=25C Startup Time (ms) Vcc=5V 15 Vcc=3.3V 10 5 0 0.0 20/35 Vcc=2.6V 0.4 0.8 1.2 1.6 Bypass Capacitor Cb ( F) 2.0 TS4994 Application information 4 Application information 4.1 Differential configuration principle The TS4994 is a monolithic full-differential input/output power amplifier. The TS4994 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 the device to always have a maximum output voltage swing, and by consequence, maximize the output power. Moreover, as the load is connected differentially, compared to a single-ended topology, the output is four times higher for the same power supply voltage. The advantages of a full-differential amplifier are: Very high PSRR (power supply rejection ratio). High common mode noise rejection. Virtually zero pop without additional circuitry, giving a faster start-up time compared with 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. But, to reach maximum performance in all tolerance situations, it is better to keep this option. The main disadvantage is: 4.2 As the differential function is directly linked to the mismatch between external resistors, paying particular attention to this mismatch is mandatory in order to get the best performance from the amplifier. Gain in typical application schematic Typical differential applications are shown in Figure 1 and Figure 2 on page 4. In the flat region of the frequency-response curve (no Cin effect), the differential gain is expressed by the relation: AV diff R feed V O+ - V O - = ------------= ----------------------------------------------------Diff input+ - Diff inputR in where Rin = Rin1 = Rin2 and Rfeed = Rfeed1 = Rfeed2. Note: For the rest of this section, Avdiff will be called AV to simplify the expression. 4.3 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. However, due to VICM limitation of the input stage (see Table 3 on page 6), the common mode feedback loop can play its role only within a defined range. This range depends upon 21/35 Application information TS4994 the values of VCC, Rin and Rfeed (AV). To have a good estimation of the VICM value, use the following formula: V CC x R in + 2 x V ic x R feed V ICM = -------------------------------------------------------------------------2 x ( R in + R feed ) (V) with Diff input+ + Diff inputV ic = ------------------------------------------------------2 (V) The result of the calculation must be in the range: 0.6V V ICM V CC - 0.9V If the result of the VICM calculation is not in this range, an input coupling capacitor must be used. Example: With VCC=2.5V, Rin = Rfeed = 20k and Vic = 2V, we find VICM = 1.63V. This is higher than 2.5V - 0.9V = 1.6V, so input coupling capacitors are required. Alternatively, you can change the Vic value. 4.4 Low and high frequency response In the low frequency region, Cin starts to have an effect. Cin forms, with Rin, a high-pass filter with a -3dB cut-off frequency. FCL is in Hz. FCL = 1 2 x x Rin x Cin (Hz) In the high-frequency region, you can limit the bandwidth by adding a capacitor (Cfeed) in parallel with Rfeed. It forms a low-pass filter with a -3dB cut-off frequency. FCH is in Hz. FCH = 1 2 x x Rfeed x Cfeed (Hz) While these bandwidth limitations are in theory attractive, in practice, because of low performance in terms of capacitor precision (and by consequence in terms of mismatching), they deteriorate the values of PSRR and CMRR. The influence of mismatching on PSRR and CMRR performance is discussed in more detail in the following sections. Example: A typical application with input coupling and feedback capacitor with FCL = 50Hz and FCH = 8kHz. We assume that the mismatching between Rin1,2 and Cfeed1,2 can be neglected. If we sweep the frequency from DC to 20kHz we observe the following with respect to the PSRR value: 22/35 From DC to 200Hz, the Cin impedance decreases from infinite to a finite value and the Cfeed impedance is high enough to be neglected. Due to the tolerance of Cin1,2, we TS4994 Application information must introduce a mismatch factor (Rin1 x Cin Rin2 x Cin2) that will decrease the PSRR performance. 4.5 From 200Hz to 5kHz, the Cin impedance is low enough to be neglected when compared with Rin, and the Cfeed impedance is high enough to be neglected as well. In this range, we can reach the PSRR performance of the TS4994 itself. From 5kHz to 20kHz, the Cin impedance is low to be neglected when compared to Rin, and the Cfeed impedance decreases to a finite value. Due to tolerance of Cfeed1,2, we introduce a mismatching factor (Rfeed1 x Cfeed1 Rfeed2 x Cfeed2) that will decrease the PSRR performance. Calculating the influence of mismatching on PSRR performance For calculating PSRR performance, we consider that Cin and Cfeed have no influence. We use the same kind of resistor (same tolerance) and R is the tolerance value in %. The following PSRR equation is valid for frequencies ranging from DC to about 1kHz. The PSRR equation is (R in %): R x 100 PSRR 20 x Log 2 (10000 - R ) (dB ) This equation doesn't include the additional performance provided by bypass capacitor filtering. If a bypass capacitor is added, it acts, together with the internal high output impedance bias, as a low-pass filter, and the result is a quite important PSRR improvement with a relatively small bypass capacitor. The complete PSRR equation (R in %, Cb in microFarad and F in Hz) is: R x 100 PSRR 20 x log --------------------------------------------------------------------------------------------------------- ( dB ) 2 2 2 (1000 - R ) x 1 + F x C b x 22.2 Example: With R = 0.1% and Cb = 0, the minimum PSRR would be -60dB. With a 100nF bypass capacitor, at 100Hz the new PSRR would be -93dB. This example is a worst case scenario, where each resistor has extreme tolerance. It illustrates the fact that with only a small bypass capacitor, the TS4994 provides high PSRR performance. Note also that this is a theoretical formula. Because the TS4994 has self-generated noise, you should consider that the highest practical PSRR reachable is about -110dB. It is therefore unreasonable to target a -120dB PSRR. 23/35 Application information TS4994 The three following graphs show PSRR versus frequency and versus bypass capacitor Cb in worst-case conditions (R = 0.1%). 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 -110 -120 -130 -140 Vcc = 5V, Vripple = 200mVpp Av = 1, Cin = 4.7F R/R = 0.1%, RL 8 Tamb = 25C, Inputs = Grounded Cb=0 Cb=0.1F Cb=1F 20 100 Cb=0.47F 1000 Frequency (Hz) 10000 20k PSRR (dB) Figure 72. PSRR vs. frequency (worst case conditions) 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 -110 -120 -130 -140 24/35 Vcc = 2.5V, Vripple = 200mVpp Av = 1, Cin = 4.7F R/R = 0.1%, RL 8 Tamb = 25C, Inputs = Grounded Cb=0 Cb=0.1F Cb=1F 20 100 Cb=0.47F 1000 Frequency (Hz) Figure 71. PSRR vs. frequency (worst case conditions) PSRR (dB) PSRR (dB) Figure 70. PSRR vs. frequency (worst case conditions) 10000 20k 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 -110 -120 -130 -140 Vcc = 3.3V, Vripple = 200mVpp Av = 1, Cin = 4.7F R/R = 0.1%, RL 8 Tamb = 25C, Inputs = Grounded Cb=0 Cb=0.1F Cb=1F 20 100 Cb=0.47F 1000 Frequency (Hz) 10000 20k TS4994 Application information The two following graphs show typical applications of the TS4994 with a random selection of four R/R values with a 0.1% tolerance. 4.6 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 -110 -120 -130 -140 Figure 74. PSRR vs. frequency with random choice condition Vcc = 5V, Vripple = 200mVpp Av = 1, Cin = 4.7F R/R 0.1%, RL 8 Tamb = 25C, Inputs = Grounded Cb=0.1F Cb=1F 20 100 PSRR (dB) PSRR (dB) Figure 73. PSRR vs. frequency with random choice condition Cb=0 Cb=0.47F 1000 Frequency (Hz) 10000 20k 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 -110 -120 -130 -140 Vcc = 2.5V, Vripple = 200mVpp Av = 1, Cin = 4.7F R/R 0.1%, RL 8 Tamb = 25C, Inputs = Grounded Cb=0.1F Cb=1F 20 100 Cb=0 Cb=0.47F 1000 Frequency (Hz) 10000 20k CMRR performance For calculating CMRR performance, we consider that Cin and Cfeed have no influence. Cb has no influence in the calculation of the CMRR. We use the same kind of resistor (same tolerance) and R is the tolerance value in %. The following CMRR equation is valid for frequencies ranging from DC to about 1kHz. The CMRR equation is (R in %): R x 200 CMRR 20 x Log 2 (10000 - R ) (dB ) Example: With R = 1%, the minimum CMRR is -34dB. This example is a worst case scenario where each resistor has extreme tolerance. Ut illustrates the fact that for CMRR, good matching is essential. As with the PSRR, due to self-generated noise, the TS4994 CMRR limitation is about -110dB. Figure 75 and Figure 76 show CMRR versus frequency and versus bypass capacitor Cb in worst-case conditions (R=0.1%). 25/35 Application information TS4994 Figure 75. CMR vs. frequency (worst case conditions) Figure 76. CMR vs. frequency (worst case conditions) 0 0 Vcc = 5V Vic = 200mVpp Av = 1, Cin = 470F R/R = 0.1%, RL 8 Tamb = 25C -20 -30 -40 -20 -30 -40 Cb=1F Cb=0 -50 -60 Vcc = 2.5V Vic = 200mVpp Av = 1, Cin = 470F R/R = 0.1%, RL 8 Tamb = 25C -10 CMRR (dB) CMRR (dB) -10 Cb=1F Cb=0 -50 20 100 1000 Frequency (Hz) -60 10000 20k 20 100 1000 Frequency (Hz) 10000 20k Figure 77 and Figure 78 show CMRR versus frequency for a typical application with a random selection of four R/R values with a 0.1% tolerance. Figure 77. CMR vs. frequency with random choice condition Figure 78. CMR vs. frequency with random choice condition 0 0 Vcc = 5V Vic = 200mVpp Av = 1, Cin = 470F R/R 0.1%, RL 8 Tamb = 25C CMRR (dB) -20 -30 Cb=1F Cb=0 -60 -30 -40 -50 -70 -80 -80 20 100 1000 Frequency (Hz) Cb=1F Cb=0 -60 -70 -90 4.7 -20 -40 -50 Vcc = 2.5V Vic = 200mVpp Av = 1, Cin = 470F R/R 0.1%, RL 8 Tamb = 25C -10 CMRR (dB) -10 10000 20k -90 20 100 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 sint (V) and V out I out = ------------- (A) RL 26/35 1000 Frequency (Hz) 10000 20k TS4994 Application information and V peak 2 P out = --------------------- (W) 2R L Therefore, the average current delivered by the supply voltage is: Equation 1 V peak I CC AVG = 2 ----------------- (A) R L The power delivered by the supply voltage is: P supply = V CC I CC AVG (W) Therefore, the power dissipated by each amplifier is: P diss = P supply - P out (W) Equation 2 2 2V CC P diss = ---------------------- P out - P out RL and the maximum value is obtained when: P diss ----------------- = 0 P out and its value is: Equation 3 Pdiss max = Note: 2 Vcc 2 2RL (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 4 P out V peak = ------------------- = -------------------P supply 4V CC The maximum theoretical value is reached when VPEAK = VCC, so: = ----- = 78.5% 4 The maximum die temperature allowable for the TS4994 is 125C. However, in case of overheating, a thermal shutdown set to 150C, puts the TS4994 in standby until the temperature of the die is reduced by about 5C. 27/35 Application information TS4994 To calculate the maximum ambient temperature Tamb allowable, you need to know: The value of the power supply voltage, VCC The value of the load resistor, RL The Rthja value for the package type Example: VCC = 5V, RL = 8, Rthja = 80C/W Using the power dissipation formula given above in Equation 3 this gives a result of: Pdissmax = 633mW Tamb is calculated as follows: Equation 5 T amb = 125 C - R TJHA x P dissmax Therefore, the maximum allowable value for Tamb is: Tamb = 125-80x0.633=74C 4.8 Decoupling of the circuit Two capacitors are needed to correctly bypass the TS4994. A power supply bypass capacitor Cs and a bias voltage bypass capacitor Cb. Cs has particular influence on the THD+N in the high frequency region (above 7kHz) and an indirect influence on power supply disturbances. With a value for Cs of 1F, you can expect similar THD+N performance to that shown in the datasheet. In the high frequency region, if Cs is lower than 1F, it increases THD+N, and disturbances on the power supply rail are less filtered. On the other hand, if Cs is higher than 1F, the disturbances on the power supply rail are more filtered. Cb has an influence on THD+N at lower frequencies, but its function is critical to the final result of PSRR (with input grounded and in the lower frequency region). 4.9 Wake-up time: tWU When the standby is released to put the device ON, the bypass capacitor Cb is not charged immediately. As 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 3 on page 6, with Cb=1F. During the wake-up time, the TS4994 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 other than 1F, refer to the graph in Figure 69 on page 20 to establish the wake-up time. 28/35 TS4994 4.10 Application information Shutdown time When the standby command is set, the time required to put the two output stages in high impedance and the internal circuitry in shutdown mode is a few microseconds. Note: In shutdown mode, the Bypass pin and Vin+, Vin- pins are short-circuited to ground by internal switches. This allows a quick discharge of the Cb and Cin capacitors. 4.11 Pop performance Due to its fully differential structure, the pop performance of the TS4994 is close to perfect. However, due to mismatching between internal resistors Rin, Rfeed, and external input capacitors Cin, some noise might remain at startup. To eliminate the effect of mismatched components, the TS4994 includes pop reduction circuitry. With this circuitry, the TS4994 is close to zero pop for all possible common applications. In addition, when the TS4994 is in standby mode, due to the high impedance output stage in this configuration, no pop is heard. Single-ended input configuration It is possible to use the TS4994 in a single-ended input configuration. However, input coupling capacitors are needed in this configuration. The schematic in Figure 79 shows this configuration using the MiniSO-8 version of the TS4994 as an example. Figure 79. Single-ended input typical application VCC + Rfeed1 20k 7 Cs 1u GND VCC Cin1 + Ve Rin1 + 220nF 20k Cin2 Rin2 GND 2 Vin- - 3 Vin+ + Vo+ 8 Vo5 220nF 20k 8 Ohms 4 Bypass Optional + 4.12 Bias Cb 1u Standby Stdby GND 1 6 GND GND TS4994IS Rfeed2 20k GND VCC 29/35 Application information TS4994 The component calculations remain the same, except for the gain. In single-ended input configuration, the formula is: Av SE = 4.13 VO + - VO - Rfeed = Ve Rin Demoboard A demoboard for the TS4994 is available. It is designed for the TS4994 in the DFN10 package. However, we can guarantee that all electrical parameters except the power dissipation are similar for all packages. For more information about this demoboard, refer to Application Note AN2013. 30/35 TS4994 5 Package mechanical data Package mechanical data In order to meet environmental requirements, STMicroelectronics offers these devices in ECOPACK(R) 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. 31/35 Package mechanical data 5.1 TS4994 DFN10 package Dimensions Ref. Millimeters Min. Typ. Max. Min. Typ. Max. 0.80 0.90 1.00 31.5 35.4 39.4 A1 0.02 0.05 0.8 2.0 A2 0.70 25.6 A3 0.20 7.9 A b 0.18 D D2 E2 2.21 0.30 7.1 2.26 1.49 1.64 2.31 87.0 0.4 11.8 89.0 91.0 118.1 1.74 58.7 0.50 0.3 9.1 118.1 3.00 e L 0.23 3.00 E 32/35 Mils 64.6 68.5 19.7 0.5 11.8 15.7 19.7 TS4994 5.2 Package mechanical data MiniSO-8 package Dimensions Ref. Millimeters Min. Typ. A Inches Max. Min. Typ. 1.1 Max. 0.043 A1 0.05 0.10 0.15 0.002 0.004 0.006 A2 0.78 0.86 0.94 0.031 0.034 0.037 b 0.25 0.33 0.40 0.010 0.013 0.016 c 0.13 0.18 0.23 0.005 0.007 0.009 D 2.90 3.00 3.10 0.114 0.118 0.122 E 4.75 4.90 5.05 0.187 0.193 0.199 E1 2.90 3.00 3.10 0.114 0.118 0.122 e 0.65 K 0 L 0.40 L1 0.55 0.026 6 0 0.70 0.016 0.10 6 0.022 0.028 0.04 33/35 Revision history 6 34/35 TS4994 Revision history Date Revision Changes 1-Sep-2003 1 Initial release. 1-Oct-2004 2 Curves updated in the document. 2-Jan-2005 4 Update mechanical data on flip-chip package. 2-Apr-2005 4 Remove data on flip-chip package. 15-Nov- 2005 5 Mechanical data updated on DFN10 package. 12-Dec-2006 6 Removed demo board views. Format update. TS4994 Please Read Carefully: Information in this document is provided solely in connection with ST products. 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