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| TS4994FC 1.2 W differential input/output audio power amplifier with selectable standby Features Differential inputs Near-zero pop & click 100dB PSRR @ 217Hz with grounded inputs Operating range from VCC = 2.5V to 5.5V 1.2W 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 9-bump flip-chip (300mm bump diameter) Lead-free package TS4994EIJT - Flip-chip (9 bumps) Gnd VOBypass VIN+ 7 6 5 VO+ Stdby VIN- 8 1 9 2 VCC 4 3 Stdby Mode The device is equipped with common mode feedback circuitry allowing outputs to be always 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. 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. 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. An internal thermal shutdown protection is also provided, making the device capable of sustaining short-circuits. Applications Mobile phones (cellular / cordless) Laptop / notebook computers PDAs Portable audio devices Order codes Part number TS4994EIKJT -40C, +85C TS4994EIJT Temperature range Package FC9 with back coating Lead free flip-chip9 Packaging Marking A94 Tape & reel A94 December 2006 Rev 2 1/35 www.st.com 35 Contents TS4994FC Contents 1 2 3 4 Application component information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Absolute maximum ratings and operating conditions . . . . . . . . . . . . . 4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 Differential configuration principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Gain in typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Common mode feedback loop limitations . . . . . . . . . . . . . . . . . . . . . . . . . 23 Low and high frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Calculating the influence of mismatching on PSRR performance . . . . . . 25 CMRR performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Power dissipation and efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Decoupling of the circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Wake-up time: tWU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Shutdown time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Pop performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Single-ended input configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 5 6 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 2/35 TS4994FC Application component information 1 Application component information Components Cs Cb Rfeed Rin Cin Functional description Supply bypass capacitor that provides power supply filtering. Bypass capacitor that provides half supply filtering. Feedback resistor that sets the closed loop gain in conjunction with Rin AV = closed loop gain = Rfeed/Rin. Inverting input resistor that sets the closed loop gain in conjunction with Rfeed. Optional input capacitor making a high pass filter together with Rin. (FCL = 1/(2RinCin). Figure 1. Typical application VCC Rfeed1 20k 2 VCC Diff. input - Cin1 + Rin1 3 VinGND Cs 1u + GND 220nF 20k Cin2 Rin2 1 Vin+ 8 Bypass Cb 1u + Bias Standby 220nF 20k Diff. Input + Optional + Mode GND Stdby 4 GND 6 GND 9 GND VCC GND VCC + 20k Vo+ 5 Vo7 8 Ohms TS4994IJ Rfeed2 3/35 Absolute maximum ratings and operating conditions TS4994FC 2 Table 1. Symbol VCC Vi Toper Tstg Tj Rthja Pdiss ESD Absolute maximum ratings and operating conditions Absolute maximum ratings Parameter Supply voltage (1) Input voltage (2) Value 6 GND to VCC -40 to + 85 -65 to +150 150 (3) Unit V V C C C C/W W kV V mA C Operating free air temperature range Storage temperature Maximum junction temperature Thermal resistance junction to ambient Power dissipation Human body model Machine model Latch-up immunity Lead temperature (soldering, 10sec) 250 internally limited 2 200 200 260 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. Symbol VCC VSM Operating conditions Parameter Supply voltage Standby mode voltage input: Standby active LOW Standby active HIGH Standby voltage input: Device ON (VSM = GND) or device OFF (VSM = VCC) Device OFF (VSM = GND) or device ON (VSM = VCC) Thermal shutdown temperature Load resistor Thermal resistance junction to ambient Value 2.5 to 5.5 VSM=GND VSM=VCC 1.5 VSTBY VCC GND VSTBY 0.4 (1) 150 4 100 Unit V V VSTBY TSD RL Rthja V C C/W 1. The minimum current consumption (ISTBY) is guaranteed when VSTBY = GND or VCC (i.e. supply rails) for the whole temperature range. 4/35 TS4994FC Electrical characteristics 3 Table 3. Symbol ICC Electrical characteristics Electrical characteristics for VCC = +5V, GND = 0V, Tamb = 25C (unless otherwise specified) Parameter Supply current No input signal, no load Standby current No input signal, VSTBY = VSM = GND, RL = 8 No input signal, VSTBY = VSM = VCC, RL = 8 Differential output offset voltage No input signal, RL = 8 Input common mode voltage CMRR -60dB Output power THD = 1% Max, F= 1kHz, RL = 8 Total harmonic distortion + noise Pout = 850mW rms, AV = 1, 20Hz F 20kHz, RL = 8 Power supply rejection ratio with inputs grounded(1) F = 217Hz, R = 8, AV = 1, Cin = 4.7F, Cb =1F Vripple = 200mVPP Common mode rejection ratio F = 217Hz, RL = 8, AV = 1, Cin = 4.7F, Cb =1F Vic = 200mVPP Signal-to-noise ratio (A-weighted filter, AV = 2.5) RL = 8, THD +N < 0.7%, 20Hz F 20kHz Gain bandwidth product RL = 8 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 Wake-up time(2) Cb =1F 0.6 0.8 1.2 0.5 Min. Typ. 4 Max. 7 Unit mA ISTBY 10 1000 nA Voo VICM Pout THD + N 0.1 10 VCC - 0.9 mV V W % PSRRIG 100 dB CMRR 90 dB SNR GBP 100 2 dB MHz VN 6 5.5 12 10.5 33 28 1.5 1 15 VRMS tWU 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. 5/35 Electrical characteristics Table 4. TS4994FC 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) Parameter Supply current no input signal, no load Standby current No input signal, VSTBY = VSM = GND, RL = 8 No input signal, VSTBY = VSM = VCC, RL = 8 Differential output offset voltage No input signal, RL = 8 Input common mode voltage CMRR -60dB Output power THD = 1% max, F= 1kHz, RL = 8 Total harmonic distortion + noise Pout = 300mW rms, AV = 1, 20Hz F 20kHz, RL = 8 Power supply rejection ratio with inputs grounded(1) F = 217Hz, R = 8, AV = 1, Cin = 4.7F, Cb =1F Vripple = 200mVPP Common mode rejection ratio F = 217Hz, RL = 8, AV = 1, Cin = 4.7F, Cb =1F Vic = 200mVPP Signal-to-noise ratio (A-weighted filter, AV = 2.5) RL = 8, THD +N < 0.7%, 20Hz F 20kHz Gain bandwidth product RL = 8 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 Wake-up time(2) Cb =1F 0.6 300 500 0.5 Min. Typ. 3 10 Max. 7 1000 Unit mA nA Symbol ICC ISTBY Voo VICM Pout THD + N 0.1 10 VCC - 0.9 mV V mW % PSRRIG 100 dB CMRR 90 dB SNR GBP 100 2 dB MHz VN 6 5.5 12 10.5 33 28 1.5 1 15 VRMS tWU 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. 6/35 TS4994FC Table 5. Symbol ICC Supply current No input signal, no load Standby current No input signal, VSTBY = VSM = GND, RL = 8 No input signal, VSTBY = VSM = VCC, RL = 8 Differential output offset voltage No input signal, RL = 8 Input common mode voltage CMRR -60dB Output power THD = 1% max, F= 1kHz, RL = 8 Total harmonic distortion + noise Pout = 225mW rms, AV = 1, 20Hz F 20kHz, RL = 8 Power supply rejection ratio with inputs grounded(1) F = 217Hz, R = 8, AV = 1, Cin = 4.7F, Cb =1F Vripple = 200mVPP Common mode rejection ratio F = 217Hz, RL = 8, AV = 1, Cin = 4.7F, Cb =1F Vic = 200mVPP Signal-to-noise ratio (A-weighted filter, AV = 2.5) RL = 8, THD +N < 0.7%, 20Hz F 20kHz Gain bandwidth product RL = 8 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 Wake-up time(2) Cb =1F 0.6 200 Electrical characteristics Electrical characteristics for VCC = +2.6V, GND = 0V, Tamb = 25C (unless otherwise specified) Parameter Min. Typ. 3 Max. 7 Unit mA ISTBY 10 1000 nA Voo VICM Pout THD + N 0.1 10 VCC- 0.9 mV V mW % 300 0.5 PSRRIG 100 dB CMRR 90 dB SNR GBP 100 2 dB MHz VN 6 5.5 12 10.5 33 28 1.5 1 15 VRMS tWU 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 TS4994FC Figure 2. Current consumption vs. power supply voltage Figure 3. Current consumption vs. standby voltage 4.0 No load 3.5 Tamb=25C Current Consumption (mA) 4.0 3.5 Current Consumption (mA) 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0 1 2 3 4 5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0 1 2 Standby mode=0V Standby mode=5V Vcc = 5V No load Tamb=25C 3 4 5 Power Supply Voltage (V) Standby Voltage (V) Figure 4. Current consumption vs. standby voltage Figure 5. Current consumption vs. standby voltage 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0.0 Vcc = 3.3V No load Tamb=25C 0.6 1.2 1.8 2.4 3.0 Standby mode=0V Standby mode=3.3V 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0.0 Vcc = 2.6V No load Tamb=25C 0.6 1.2 1.8 2.4 Standby mode=0V Standby mode=2.6V Current Consumption (mA) Standby Voltage (V) Current Consumption (mA) Standby Voltage (V) Figure 6. Differential DC output voltage vs. common mode input voltage Figure 7. Power dissipation vs. output power 1000 Av = 1 Tamb = 25C Power Dissipation (W) 1.4 Vcc=5V 1.2 F=1kHz THD+N<1% 1.0 0.8 0.6 0.4 0.2 RL=16 RL=8 100 Voo (mV) Vcc=3.3V Vcc=2.5V RL=4 10 Vcc=5V 1 0.1 0.01 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 0.0 0.0 0.2 0.4 0.6 Common Mode Input Voltage (V) 0.8 1.0 1.2 Output Power (W) 1.4 1.6 8/35 TS4994FC Electrical characteristics Figure 8. 0.6 Power dissipation vs. output power Figure 9. 0.40 0.35 RL=4 Power dissipation vs. output power Vcc=3.3V F=1kHz 0.5 THD+N<1% Power Dissipation (W) Vcc=2.6V F=1kHz THD+N<1% RL=4 0.4 0.3 0.2 RL=8 0.1 RL=16 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Power Dissipation (W) 0.30 0.25 0.20 0.15 RL=8 0.10 0.05 0.00 0.0 RL=16 0.1 0.2 Output Power (W) 0.3 0.4 Output Power (W) Figure 10. Output power vs. power supply voltage 2.4 2.2 RL = 4 F = 1kHz 2.0 BW < 125kHz 1.8 Tamb = 25C 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 2.5 3.0 3.5 4.0 Vcc (V) 4.5 5.0 5.5 THD+N=1% Figure 11. Output power vs. power supply voltage 2.0 RL = 8 F = 1kHz 1.6 BW < 125kHz Tamb = 25C 1.4 1.8 1.2 1.0 0.8 0.6 0.4 0.2 0.0 2.5 3.0 3.5 4.0 Vcc (V) 4.5 5.0 5.5 THD+N=1% THD+N=10% Output power (W) Figure 12. Output power vs. power supply voltage 1.2 RL = 16 F = 1kHz 1.0 BW < 125kHz Tamb = 25C 0.8 0.6 0.4 THD+N=1% 0.2 0.0 2.5 Output power (W) THD+N=10% Figure 13. Output power vs. power supply voltage 0.6 0.5 Output power (W) Output power (W) RL = 32 F = 1kHz BW < 125kHz Tamb = 25C THD+N=10% THD+N=10% 0.4 0.3 0.2 THD+N=1% 0.1 0.0 2.5 3.0 3.5 4.0 Vcc (V) 4.5 5.0 5.5 3.0 3.5 4.0 Vcc (V) 4.5 5.0 5.5 9/35 Electrical characteristics TS4994FC Figure 14. Power derating curves Flip-Chip Package Power Dissipation (W) Figure 15. Open loop gain vs. frequency 0 1.2 1.0 0.8 Gain (dB) Heat sink surface 100mm (See demoboard) 2 60 Gain 40 -80 20 Phase -120 Phase () Phase () Phase () -40 0.6 0.4 0.2 0.0 No Heat sink 0 Vcc = 5V ZL = 8 + 500pF Tamb = 25C 1 10 100 1000 -20 -160 0 25 50 75 100 125 -40 0.1 -200 10000 Ambiant Temperature ( C) Frequency (kHz) Figure 16. Open loop gain vs. frequency 0 60 Gain 40 Gain (dB) Figure 17. Open loop gain vs. frequency 0 60 Gain 40 Gain (dB) -40 Phase () -40 -80 20 Phase -120 -80 20 Phase -120 0 Vcc = 3.3V ZL = 8 + 500pF Tamb = 25C 1 10 100 1000 0 Vcc = 2.6V ZL = 8 + 500pF Tamb = 25C 1 10 100 1000 -20 -160 -20 -160 -40 0.1 -200 10000 -40 0.1 -200 10000 Frequency (kHz) Frequency (kHz) Figure 18. Closed loop gain vs. frequency 10 Phase 0 Gain -40 Phase () Figure 19. Closed loop gain vs. frequency 10 Phase 0 Gain -40 0 0 Gain (dB) -20 Vcc = 5V Av = 1 ZL = 8 + 500pF Tamb = 25C 1 10 100 1000 -120 Gain (dB) -10 -80 -10 -80 -20 Vcc = 3.3V Av = 1 ZL = 8 + 500pF Tamb = 25C 1 10 100 1000 -120 -30 -160 -30 -160 -40 0.1 -200 10000 -40 0.1 -200 10000 Frequency (kHz) Frequency (kHz) 10/35 TS4994FC Electrical characteristics Figure 20. Closed loop gain vs. frequency 10 Phase 0 Gain -40 Phase () Figure 21. PSRR vs. frequency 0 -10 -20 -30 -40 -50 -60 -70 -80 Cb=1F -90 -100 -110 -120 Cb=0 Vcc = 5V Vripple = 200mVpp Inputs = Grounded Av = 1, Cin = 4.7F RL 8 Tamb = 25C 0 Gain (dB) -10 -80 PSRR (dB) Cb=0.1F Cb=0.47F -20 Vcc = 2.6V Av = 1 ZL = 8 + 500pF Tamb = 25C 1 10 100 1000 -120 -30 -160 -40 0.1 -200 10000 20 100 Frequency (kHz) 1000 Frequency (Hz) 10000 20k Figure 22. PSRR vs. frequency 0 -10 -20 -30 PSRR (dB) Figure 23. PSRR vs. frequency 0 -50 -60 -70 -80 -90 -100 -110 -120 20 Cb=0.1F Cb=0.47F Cb=1F PSRR (dB) -40 Vcc = 3.3V Vripple = 200mVpp Inputs = Grounded Av = 1, Cin = 4.7F RL 8 Tamb = 25C -10 -20 -30 -40 -50 -60 -70 -80 -90 Cb=0 -100 -110 -120 Vcc = 2.6V Vripple = 200mVpp Inputs = Grounded Av = 1, Cin = 4.7F RL 8 Tamb = 25C Cb=0.1F Cb=0.47F Cb=1F Cb=0 100 1000 Frequency (Hz) 10000 20k 20 100 1000 Frequency (Hz) 10000 20k Figure 24. PSRR vs. frequency 0 -10 -20 -30 PSRR (dB) Figure 25. PSRR vs. frequency 0 -50 -60 -70 -80 -90 -100 -110 -120 20 Cb=0.1F Cb=0.47F PSRR (dB) -40 Vcc = 5V Vripple = 200mVpp Inputs = Grounded Av = 2.5, Cin = 4.7F RL 8 Tamb = 25C -10 -20 -30 -40 -50 -60 -70 -80 -90 Cb=0 -100 -110 -120 Vcc = 3.3V Vripple = 200mVpp Inputs = Grounded Av = 2.5, Cin = 4.7F RL 8 Tamb = 25C Cb=0.1F Cb=0.47F Cb=1F Cb=1F Cb=0 100 1000 Frequency (Hz) 10000 20k 20 100 1000 Frequency (Hz) 10000 20k 11/35 Electrical characteristics TS4994FC Figure 26. PSRR vs. frequency 0 -10 -20 -30 PSRR (dB) Figure 27. PSRR vs. frequency 0 -50 -60 -70 -80 -90 -100 -110 -120 20 Cb=0.1F Cb=0.47F PSRR (dB) -40 Vcc = 2.6V Vripple = 200mVpp Inputs = Grounded Av = 2.5, Cin = 4.7F RL 8 Tamb = 25C -10 -20 -30 -40 -50 -60 -70 -80 -90 Cb=0 -100 -110 -120 Vcc = 5V Vripple = 200mVpp Inputs = Floating Rfeed = 20k RL 8 Tamb = 25C Cb=0.1F Cb=0.47F Cb=1F Cb=1F Cb=0 100 1000 Frequency (Hz) 10000 20k 20 100 1000 Frequency (Hz) 10000 20k Figure 28. PSRR vs. frequency 0 -10 -20 -30 PSRR (dB) Figure 29. PSRR vs. frequency 0 -50 -60 -70 -80 -90 -100 -110 -120 20 Cb=0.1F Cb=0.47F Cb=1F PSRR (dB) -40 Vcc = 3.3V Vripple = 200mVpp Inputs = Floating Rfeed = 20k RL 8 Tamb = 25C -10 -20 -30 -40 -50 -60 -70 -80 -90 Cb=0 -100 -110 -120 Vcc = 2.6V Vripple = 200mVpp Inputs = Floating Rfeed = 20k RL 8 Tamb = 25C Cb=0.1F Cb=0.47F Cb=1F Cb=0 100 1000 Frequency (Hz) 10000 20k 20 100 1000 Frequency (Hz) 10000 20k Figure 30. PSRR vs. common mode input voltage 0 Vcc = 5V Vripple = 200mVpp Inputs Grounded F = 217Hz Av = 1 RL 8 Tamb = 25C Cb=0 -80 Figure 31. PSRR vs. common mode input voltage 0 -20 -20 PSRR(dB) -40 PSRR(dB) -60 Cb=1F Cb=0.47F Cb=0.1F -40 -60 -80 Vcc = 3.3V Vripple = 200mVpp Inputs Grounded F = 217Hz Av = 1 RL 8 Tamb = 25C Cb=0 Cb=1F Cb=0.47F Cb=0.1F -100 0 1 2 3 4 5 -100 0.0 0.6 1.2 1.8 2.4 3.0 Common Mode Input Voltage (V) Common Mode Input Voltage (V) 12/35 TS4994FC Electrical characteristics Figure 32. PSRR vs. common mode input voltage Figure 33. CMRR vs. frequency 0 -20 0 Vcc = 2.5V Vripple = 200mVpp Inputs Grounded F = 217Hz Av = 1 RL 8 Tamb = 25C Cb=0 Cb=1F Cb=0.47F Cb=0.1F -10 -20 -30 CMRR (dB) PSRR(dB) -40 -60 -80 -40 -50 -60 -70 -80 -90 -100 -110 -120 Vcc = 5V Vic = 200mVpp Av = 1, Cin = 470F RL 8 Tamb = 25C Cb=1F Cb=0.47F Cb=0.1F Cb=0 -100 0.0 0.5 1.0 1.5 2.0 2.5 20 100 Common Mode Input Voltage (V) 1000 Frequency (Hz) 10000 20k Figure 34. CMRR vs. frequency 0 -10 -20 -30 CMRR (dB) Figure 35. CMRR vs. frequency 0 -50 -60 -70 -80 -90 -100 -110 -120 20 100 CMRR (dB) -40 Vcc = 3.3V Vic = 200mVpp Av = 1, Cin = 470F RL 8 Tamb = 25C -10 -20 -30 Cb=1F Cb=0.47F Cb=0.1F Cb=0 -40 -50 -60 -70 -80 -90 -100 -110 1000 Frequency (Hz) 10000 20k -120 20 Vcc = 2.6V Vic = 200mVpp Av = 1, Cin = 470F RL 8 Tamb = 25C Cb=1F Cb=0.47F Cb=0.1F Cb=0 100 1000 Frequency (Hz) 10000 20k Figure 36. CMRR vs. frequency 0 -10 -20 -30 CMRR (dB) Figure 37. CMRR vs. frequency 0 -40 -50 -60 -70 -80 -90 -100 20 CMRR (dB) Vcc = 5V Vic = 200mVpp Av = 2.5, Cin = 470F RL 8 Tamb = 25C Cb=1F Cb=0.47F Cb=0.1F Cb=0 -10 -20 -30 -40 -50 -60 -70 -80 -90 Vcc = 3.3V Vic = 200mVpp Av = 2.5, Cin = 470F RL 8 Tamb = 25C Cb=1F Cb=0.47F Cb=0.1F Cb=0 100 1000 Frequency (Hz) 10000 20k -100 20 100 1000 Frequency (Hz) 10000 20k 13/35 Electrical characteristics TS4994FC Figure 38. CMRR vs. frequency Figure 39. CMRR vs. common mode input voltage 0 -10 -20 -30 CMRR (dB) CMRR(dB) -40 -50 -60 -70 -80 -90 -100 20 Vcc = 2.6V Vic = 200mVpp Av = 2.5, Cin = 470F RL 8 Tamb = 25C Cb=1F Cb=0.47F Cb=0.1F Cb=0 0 Vcc=3.3V -20 -40 -60 -80 -100 Vcc=2.5V Vic = 200mVpp F = 217Hz Av = 1, Cb = 1F RL 8 Tamb = 25C Vcc=5V 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 100 1000 Frequency (Hz) 10000 20k 0.0 Common Mode Input Voltage (V) Figure 40. CMRR vs. common mode input voltage Figure 41. THD+N vs. output power 10 0 Vcc=3.3V -20 CMRR(dB) Vcc=2.5V Vic = 200mVpp F = 217Hz Av = 1, Cb = 0 RL 8 Tamb = 25C THD + N (%) -40 -60 -80 -100 0.0 0.5 1.0 1.5 2.0 RL = 4 F = 20Hz Av = 1 1 Cb = 1F BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=3.3V Vcc=5V 0.1 Vcc=5V 2.5 3.0 3.5 4.0 4.5 5.0 0.01 1E-3 0.01 0.1 Output Power (W) 1 Common Mode Input Voltage (V) Figure 42. THD+N vs. output power 10 RL = 4 F = 20Hz Av = 2.5 Cb = 1F 1 BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=3.3V Figure 43. THD+N vs. output power 10 RL = 4 F = 20Hz Av = 7.5 Cb = 1F 1 BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=3.3V Vcc=5V THD + N (%) Vcc=5V 0.1 THD + N (%) 1 0.1 0.01 1E-3 0.01 0.1 Output Power (W) 0.01 1E-3 0.01 0.1 Output Power (W) 1 14/35 TS4994FC Electrical characteristics Figure 44. THD+N vs. output power 10 RL = 8 F = 20Hz Av = 1 1 Cb = 1F BW < 125kHz Tamb = 25C 0.1 Figure 45. THD+N vs. output power 10 RL = 8 F = 20Hz Av = 2.5 1 Cb = 1F BW < 125kHz Tamb = 25C 0.1 Vcc=2.6V Vcc=2.6V Vcc=3.3V Vcc=5V THD + N (%) Vcc=5V 0.01 1E-3 1E-3 0.01 0.1 Output Power (W) 1 THD + N (%) Vcc=3.3V 0.01 1E-3 1E-3 0.01 0.1 Output Power (W) 1 Figure 46. THD+N vs. output power 10 RL = 8 F = 20Hz Av = 7.5 Cb = 1F 1 BW < 125kHz Tamb = 25C Figure 47. THD+N vs. output power 10 RL = 16 F = 20Hz 1 Av = 1 Cb = 1F BW < 125kHz Tamb = 25C 0.1 Vcc=2.6V Vcc=2.6V Vcc=3.3V Vcc=5V THD + N (%) THD + N (%) Vcc=3.3V Vcc=5V 0.1 0.01 0.01 1E-3 0.01 0.1 Output Power (W) 1 1E-3 1E-3 0.01 0.1 Output Power (W) 1 Figure 48. THD+N vs. output power 10 RL = 16 F = 20Hz 1 Av = 2.5 Cb = 1F BW < 125kHz Tamb = 25C 0.1 Vcc=2.6V Vcc=3.3V Figure 49. THD+N vs. output power 10 RL = 16 F = 20Hz 1 Av = 7.5 Cb = 1F BW < 125kHz Tamb = 25C 0.1 Vcc=2.6V Vcc=3.3V THD + N (%) Vcc=5V THD + N (%) Vcc=5V 0.01 0.01 1E-3 1E-3 0.01 0.1 Output Power (W) 1 1E-3 1E-3 0.01 0.1 Output Power (W) 1 15/35 Electrical characteristics TS4994FC Figure 50. THD+N vs. output power 10 RL = 4 F = 1kHz Av = 1 1 Cb = 1F BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=3.3V Vcc=5V Figure 51. THD+N vs. output power 10 RL = 4 F = 1kHz Av = 2.5 Cb = 1F 1 BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=3.3V THD + N (%) THD + N (%) Vcc=5V 0.1 0.1 0.01 1E-3 0.01 0.1 Output Power (W) 1 0.01 1E-3 0.01 0.1 Output Power (W) 1 Figure 52. THD+N vs. output power 10 RL = 4 F = 1kHz Av = 7.5 Cb = 1F BW < 125kHz 1 Tamb = 25C Vcc=2.6V Vcc=3.3V Figure 53. THD+N vs. output power 10 RL = 8 F = 1kHz Av = 1 1 Cb = 1F BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=3.3V Vcc=5V THD + N (%) Vcc=5V THD + N (%) 1 0.1 0.1 0.01 1E-3 0.01 0.1 Output Power (W) 1E-3 0.01 0.1 Output Power (W) 1 Figure 54. THD+N vs. output power 10 RL = 8 F = 1kHz Av = 2.5 1 Cb = 1F BW < 125kHz Tamb = 25C Figure 55. THD+N vs. output power 10 RL = 8 F = 1kHz Av = 7.5 Cb = 1F 1 BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=3.3V Vcc=5V Vcc=2.6V Vcc=3.3V Vcc=5V THD + N (%) 0.1 THD + N (%) 1 0.1 0.01 1E-3 0.01 0.1 Output Power (W) 0.01 1E-3 0.01 0.1 Output Power (W) 1 16/35 TS4994FC Electrical characteristics Figure 56. THD+N vs. output power 10 RL = 16 F = 1kHz 1 Av = 1 Cb = 1F BW < 125kHz Tamb = 25C 0.1 Vcc=2.6V Vcc=3.3V Figure 57. THD+N vs. output power 10 RL = 16 F = 1kHz 1 Av = 2.5 Cb = 1F BW < 125kHz Tamb = 25C 0.1 Vcc=2.6V Vcc=3.3V Vcc=5V THD + N (%) Vcc=5V 0.01 1E-3 1E-3 0.01 0.1 Output Power (W) 1 THD + N (%) 0.01 1E-3 1E-3 0.01 0.1 Output Power (W) 1 Figure 58. THD+N vs. output power 10 RL = 16 F = 1kHz Av = 7.5 1 Cb = 1F BW < 125kHz Tamb = 25C 0.1 Vcc=2.6V Vcc=3.3V Figure 59. THD+N vs. output power 10 RL = 4 F = 20kHz Av = 1 1 Cb = 1F BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=3.3V Vcc=5V THD + N (%) Vcc=5V THD + N (%) 1 0.1 0.01 1E-3 0.01 0.1 Output Power (W) 0.01 1E-3 0.01 0.1 Output Power (W) 1 Figure 60. THD+N vs. output power 10 RL = 4 F = 20kHz Av = 2.5 Cb = 1F BW < 125kHz Tamb = 25C 1 Vcc=2.6V Vcc=3.3V Vcc=5V Figure 61. THD+N vs. output power 10 RL = 4 F = 20kHz Av = 7.5 Cb = 1F BW < 125kHz Tamb = 25C 1 Vcc=2.6V Vcc=3.3V Vcc=5V THD + N (%) 0.1 1E-3 0.01 0.1 Output Power (W) 1 THD + N (%) 0.1 1E-3 0.01 0.1 Output Power (W) 1 17/35 Electrical characteristics TS4994FC Figure 62. THD+N vs. output power 10 RL = 8 F = 20kHz Av = 1 Cb = 1F BW < 125kHz 1 Tamb = 25C Figure 63. THD+N vs. output power 10 RL = 8 F = 20kHz Av = 2.5 Cb = 1F BW < 125kHz 1 Tamb = 25C Vcc=2.6V Vcc=3.3V Vcc=5V Vcc=2.6V Vcc=3.3V Vcc=5V THD + N (%) 0.1 1E-3 0.01 0.1 Output Power (W) 1 THD + N (%) 0.1 1E-3 0.01 0.1 Output Power (W) 1 Figure 64. THD+N vs. output power 10 RL = 8 F = 20kHz Av = 7.5 Cb = 1F BW < 125kHz 1 Tamb = 25C Figure 65. THD+N vs. output power 10 RL = 16 F = 20kHz Av = 1 Cb = 1F 1 BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=3.3V Vcc=2.6V THD + N (%) Vcc=5V THD + N (%) Vcc=3.3V Vcc=5V 0.1 0.1 0.01 1E-3 1E-3 0.01 0.1 Output Power (W) 1 0.01 0.1 Output Power (W) 1 Figure 66. THD+N vs. output power 10 RL = 16 F = 20kHz Av = 2.5 Cb = 1F 1 BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=3.3V Vcc=5V Figure 67. THD+N vs. output power 10 RL = 16 F = 20kHz Av = 7.5 Cb = 1F BW < 125kHz Tamb = 25C Vcc=2.6V Vcc=3.3V Vcc=5V THD + N (%) THD + N (%) 1 1 0.1 0.01 1E-3 0.1 0.01 0.1 Output Power (W) 1E-3 0.01 0.1 Output Power (W) 1 18/35 TS4994FC Electrical characteristics Figure 68. THD+N vs. frequency 10 RL = 4 Av = 1 Cb = 1F 1 Bw < 125kHz Tamb = 25C THD + N (%) Figure 69. THD+N vs. frequency 10 RL = 4 Av = 7.5 Cb = 1F Bw < 125kHz 1 Tamb = 25C THD + N (%) Vcc=2.6V, Po=350mW 0.1 0.1 Vcc=2.6V, Po=350mW 0.01 Vcc=5V, Po=1W Vcc=5V, Po=1W 1E-3 0.01 20 100 1000 Frequency (Hz) 10000 20k 20 100 1000 Frequency (Hz) 10000 20k Figure 70. THD+N vs. frequency 10 RL = 8 Av = 1 Cb = 1F 1 Bw < 125kHz Tamb = 25C THD + N (%) Figure 71. THD+N vs. frequency 10 RL = 8 Av = 7.5 Cb = 1F Bw < 125kHz 1 Tamb = 25C THD + N (%) Vcc=2.6V, Po=225mW 0.1 Vcc=5V, Po=850mW Vcc=5V, Po=850mW 0.1 0.01 Vcc=2.6V, Po=225mW 1E-3 0.01 20 100 1000 Frequency (Hz) 10000 20k 20 100 1000 Frequency (Hz) 10000 20k Figure 72. THD+N vs. frequency 10 RL = 16 Av = 1 Cb = 1F 1 Bw < 125kHz Tamb = 25C THD + N (%) Figure 73. THD+N vs. frequency 10 RL = 16 Av = 7.5 Cb = 1F 1 Bw < 125kHz Tamb = 25C THD + N (%) 0.1 Vcc=2.6V, Po=155mW 0.1 Vcc=5V, Po=600mW 0.01 Vcc=5V, Po=600mW 0.01 Vcc=2.6V, Po=155mW 1E-3 20 100 1000 Frequency (Hz) 10000 20k 1E-3 20 100 1000 Frequency (Hz) 10000 20k 19/35 Electrical characteristics TS4994FC Figure 74. THD+N vs. output power 10 RL = 4 Vcc = 5V Av = 1 Cb = 0 1 BW < 125kHz Tamb = 25C Figure 75. THD+N vs. output power 10 RL = 4 Vcc = 5V Av = 7.5, Cb = 0 BW < 125kHz Tamb = 25C 1 F=1kHz F=20Hz F=20kHz F=20kHz THD + N (%) F=1kHz 0.1 F=20Hz 0.01 1E-3 0.01 0.1 Output Power (W) 1 THD + N (%) 0.1 1E-3 0.01 0.1 Output Power (W) 1 Figure 76. THD+N vs. output power 10 RL = 4 Vcc = 2.6V Av = 1, Cb = 0 1 BW < 125kHz Tamb = 25C 0.1 Figure 77. THD+N vs. output power 10 RL = 4 Vcc = 2.6V Av = 7.5, Cb = 0 BW < 125kHz 1 Tamb = 25C F=20kHz THD + N (%) THD + N (%) F=1kHz F=20kHz F=20Hz F=1kHz 0.01 F=20Hz 0.1 1E-3 1E-3 0.01 Output Power (W) 0.1 1E-3 0.01 Output Power (W) 0.1 Figure 78. THD+N vs. output power 10 RL = 8 Vcc = 5V Av = 1 1 Cb = 0 BW < 125kHz Tamb = 25C 0.1 F=20Hz Figure 79. THD+N vs. output power 10 RL = 8 Vcc = 5V Av = 7.5, Cb = 0 BW < 125kHz 1 Tamb = 25C F=20kHz F=20kHz F=1kHz THD + N (%) THD + N (%) F=1kHz 0.1 0.01 F=20Hz 1E-3 0.01 0.1 Output Power (W) 1 0.01 1E-3 0.01 0.1 Output Power (W) 1 20/35 TS4994FC Electrical characteristics Figure 80. THD+N vs. output power 10 RL = 8 Vcc = 2.6V Av = 1, Cb = 0 1 BW < 125kHz Tamb = 25C 0.1 Figure 81. THD+N vs. output power 10 RL = 8 Vcc = 2.6V Av = 7.5, Cb = 0 BW < 125kHz 1 Tamb = 25C F=20kHz F=20kHz F=1kHz THD + N (%) THD + N (%) 0.1 0.01 F=20Hz F=20Hz F=1kHz 1E-3 1E-3 0.01 Output Power (W) 0.1 0.01 1E-3 0.01 Output Power (W) 0.1 Figure 82. THD+N vs. output power 10 RL = 16 Vcc = 5V Av = 1, Cb = 0 1 BW < 125kHz Tamb = 25C 0.1 Figure 83. THD+N vs. output power 10 RL = 16 Vcc = 5V Av = 7.5, Cb = 0 1 BW < 125kHz Tamb = 25C F=20kHz THD + N (%) THD + N (%) F=20kHz F=1kHz 0.1 F=1kHz 0.01 F=20Hz F=20Hz 0.01 1 1E-3 1E-3 1E-3 0.01 0.1 Output Power (W) 0.01 0.1 Output Power (W) 1 Figure 84. THD+N vs. output power 10 RL = 16 Vcc = 2.6V Av = 1, Cb = 0 1 BW < 125kHz Tamb = 25C 0.1 Figure 85. THD+N vs. output power 10 RL = 16 Vcc = 2.6V Av = 7.5, Cb = 0 BW < 125kHz 1 Tamb = 25C F=20kHz F=20kHz F=1kHz THD + N (%) THD + N (%) 0.1 F=20Hz 0.01 F=20Hz F=1kHz 0.01 1E-3 1E-3 0.01 Output Power (W) 0.1 1E-3 0.01 Output Power (W) 0.1 21/35 Electrical characteristics TS4994FC Figure 86. SNR vs. power supply voltage with Figure 87. SNR vs. power supply voltage with unweighted filter A-weighted filter 110 RL=16 Signal to Noise Ratio (dB) Signal to Noise Ratio (dB) 110 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 RL=4 105 100 95 RL=4 90 Av = 2.5 85 Cb = 1F THD+N < 0.7% Tamb = 25C 80 2.5 3.0 RL=8 3.5 4.0 4.5 5.0 3.5 4.0 4.5 5.0 Power Supply Voltage (V) Power Supply Voltage (V) Figure 88. Startup time vs. bypass capacitor 20 Tamb=25C Vcc=5V Startup Time (ms) 15 Vcc=3.3V 10 5 Vcc=2.6V 0 0.0 0.4 0.8 1.2 1.6 Bypass Capacitor Cb ( F) 2.0 22/35 TS4994FC Application information 4 4.1 Application information 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. 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. The main disadvantage is: 4.2 Gain in typical application schematic A typical differential application is shown in Figure 1 on page 3. In the flat region of the frequency-response curve (no Cin effect), the differential gain is expressed by the relation: AV R feed V O+ - V O = ----------------------------------------------------- = ------------Diff input+ - Diff inputR in diff 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 5), the common mode feedback loop can play its role only within a defined range. This range depends upon 23/35 Application information TS4994FC 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: 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 24/35 TS4994FC Application information must introduce a mismatch factor (Rin1 x Cin Rin2 x Cin2) that will decrease the PSRR performance. 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. 4.5 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 is -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. 25/35 Application information TS4994FC The three following graphs show PSRR versus frequency and versus bypass capacitor Cb in worst-case conditions (R = 0.1%). Figure 89. PSRR vs. frequency (worst case conditions) 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 -110 -120 -130 -140 Figure 90. PSRR vs. frequency (worst case conditions) 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 PSRR (dB) Vcc = 3.3V, Vripple = 200mVpp Av = 1, Cin = 4.7F R/R = 0.1%, RL 8 Tamb = 25C, Inputs = Grounded Cb=0 PSRR (dB) Cb=0.1F Cb=0.1F Cb=1F 20 100 Cb=0.47F 1000 Frequency (Hz) 10000 20k Cb=1F 20 100 Cb=0.47F 1000 Frequency (Hz) 10000 20k Figure 91. PSRR vs. frequency (worst case conditions) 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 PSRR (dB) Cb=0.1F Cb=1F 20 100 Cb=0.47F 1000 Frequency (Hz) 10000 20k 26/35 TS4994FC 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. Figure 92. PSRR vs. frequency with random choice condition 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 -110 -120 -130 -140 Figure 93. PSRR vs. frequency with random choice condition 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 PSRR (dB) Vcc = 2.5V, Vripple = 200mVpp Av = 1, Cin = 4.7F R/R 0.1%, RL 8 Tamb = 25C, Inputs = Grounded PSRR (dB) Cb=0.1F Cb=0 Cb=0.1F Cb=0 Cb=1F 20 100 Cb=0.47F 1000 Frequency (Hz) 10000 20k Cb=1F 20 100 Cb=0.47F 1000 Frequency (Hz) 10000 20k 4.6 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 94 and Figure 95 show CMRR versus frequency and versus bypass capacitor Cb in worst-case conditions (R=0.1%). 27/35 Application information TS4994FC Figure 94. CMRR vs. frequency (worst case conditions) 0 -10 -20 -30 -40 -50 -60 Vcc = 5V Vic = 200mVpp Av = 1, Cin = 470F R/R = 0.1%, RL 8 Tamb = 25C Figure 95. CMRR vs. frequency (worst case conditions) 0 -10 -20 -30 -40 -50 -60 Vcc = 2.5V Vic = 200mVpp Av = 1, Cin = 470F R/R = 0.1%, RL 8 Tamb = 25C CMRR (dB) Cb=1F Cb=0 CMRR (dB) Cb=1F Cb=0 20 100 1000 Frequency (Hz) 10000 20k 20 100 1000 Frequency (Hz) 10000 20k Figure 96 and Figure 97 show CMRR versus frequency for a typical application with a random selection of four R/R values with a 0.1% tolerance. Figure 96. CMRR vs. frequency with random selection condition 0 -10 -20 CMRR (dB) Figure 97. CMRR vs. frequency with random selection condition 0 -40 -50 -60 -70 -80 -90 20 100 1000 Frequency (Hz) 10000 20k Cb=1F Cb=0 CMRR (dB) -30 Vcc = 5V Vic = 200mVpp Av = 1, Cin = 470F R/R 0.1%, RL 8 Tamb = 25C -10 -20 -30 -40 -50 -60 -70 -80 -90 20 Vcc = 2.5V Vic = 200mVpp Av = 1, Cin = 470F R/R 0.1%, RL 8 Tamb = 25C Cb=1F Cb=0 100 1000 Frequency (Hz) 10000 20k 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 out = V peak sint (V) and V out I out = ------------ (A) RL 28/35 TS4994FC and V peak 2 P out = -------------------- (W) 2R L Application information 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 = 2 Vcc 2 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 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. 29/35 Application information TS4994FC 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-flipchip = 100C/W (100mm copper heatsink) 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=62C 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 5, 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 88 on page 22 to establish the wake-up time. 30/35 TS4994FC Application information 4.10 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. 4.12 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 98 shows an example of this configuration. Figure 98. Single-ended input typical application VCC Rfeed1 20k 2 VCC Ve Cin1 + Rin1 3 VinGND + 220nF 20k Cin2 Rin2 GND 1 Vin+ 8 Bypass + Bias Standby 220nF 20k + Cb 1u Mode GND Stdby 4 GND 6 GND 9 GND VCC GND VCC The component calculations remain the same, except for the gain. In single-ended input configuration, the formula is: Av SE = VO + - VO - Rfeed = Ve Rin + 20k Cs 1u Vo+ 5 Vo7 8 Ohms TS4994IJ Rfeed2 31/35 Package information TS4994FC 5 Package information 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. Flip-chip package (9 bumps) Dimensions in millimeters unless otherwise indicated. Figure 99. Pinout (top view) Gnd VOBypass VIN+ 7 6 5 VO+ Stdby VIN- 8 1 9 2 VCC 4 3 Stdby Mode * Balls are underneath Figure 100. Marking (top view) E A94 YWW 32/35 TS4994FC Figure 101. Dimensions 1.63 mm Package information 1.63 mm 0.5mm 0.5mm 0.25mm Die size: 1.63mm x 1.63mm 30m Die height (including bumps): 600m Bumps diameter: 315m 50m Bump diameter before reflow: 300m 10m Bump height: 250m 40m Back coating height: 40m 10m Die height: 350m 20m Pitch: 500m 50m Coplanarity: 60m max 100m 600m Figure 102. Tape & reel dimensions 4 1.5 1 A A Die size Y + 70m 1 8 Die size X + 70m 4 All dimensions are in mm User direction of feed 33/35 Revision history TS4994FC 6 Revision history Table 6. Date 17-Mar-2005 12-Dec-2006 Document revision history Revision 1 2 Initial release. Template update. Changes 34/35 TS4994FC 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. Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no liability whatsoever relating to the choice, selection or use of the ST products and services described herein. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. If any part of this document refers to any third party products or services it shall not be deemed a license grant by ST for the use of such third party products or services, or any intellectual property contained therein or considered as a warranty covering the use in any manner whatsoever of such third party products or services or any intellectual property contained therein. UNLESS OTHERWISE SET FORTH IN ST'S TERMS AND CONDITIONS OF SALE ST DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY WITH RESPECT TO THE USE AND/OR SALE OF ST PRODUCTS INCLUDING WITHOUT LIMITATION IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION), OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. UNLESS EXPRESSLY APPROVED IN WRITING BY AN AUTHORIZED ST REPRESENTATIVE, ST PRODUCTS ARE NOT RECOMMENDED, AUTHORIZED OR WARRANTED FOR USE IN MILITARY, AIR CRAFT, SPACE, LIFE SAVING, OR LIFE SUSTAINING APPLICATIONS, NOR IN PRODUCTS OR SYSTEMS WHERE FAILURE OR MALFUNCTION MAY RESULT IN PERSONAL INJURY, DEATH, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE. ST PRODUCTS WHICH ARE NOT SPECIFIED AS "AUTOMOTIVE GRADE" MAY ONLY BE USED IN AUTOMOTIVE APPLICATIONS AT USER'S OWN RISK. Resale of ST products with provisions different from the statements and/or technical features set forth in this document shall immediately void any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoever, any liability of ST. ST and the ST logo are trademarks or registered trademarks of ST in various countries. Information in this document supersedes and replaces all information previously supplied. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners. (c) 2006 STMicroelectronics - All rights reserved STMicroelectronics group of companies Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America www.st.com 35/35 |
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