A21SP16 3 W filter-free class-D audio power amplifier Datasheet - production data Output power: 1.4 W @ 5 V or 0.45 W @ 3 V into 8 with 1% THD+N max Pin connection Adjustable gain via external resistors IN+ GND OUT- 1/A1 2/A2 3/A3 Low current consumption 2 mA @ 3 V VDD VDD GND Efficiency: 88% typ. 4/B1 5/B2 6/B3 Signal to noise ratio: 85 dB typ. IN- STBY OUT+ PSRR: 63 dB typ. @ 217 Hz with 6 dB gain 8/C2 9/C3 7/C1 PWM base frequency: 250 kHz IN+: positive differential input IN-: negative differential input VDD: analog power supply GND: power supply ground STBY: standby pin (active low) OUT+: positive differential output OUT-: negative differential output Low pop & click noise Thermal shutdown protection Available in flip-chip 9 x 300 m (Pb-free) Block diagram Applications B1 Wearable B2 Vcc 300k C2 Stdby C1 A1 Internal Bias Fitness and healthcare Out+ 150k Cellular phone C3 Output - InIn+ + PWM PDA H Bridge A3 150k Description Out- Oscillator The A21SP16 is a differential class-D BTL power amplifier. It is able to drive up to 2.3 W into a 4 load and 1.4 W into a 8 load at 5 V. It achieves outstanding efficiency (88% typ.) compared to classical Class-AB audio amps. GND A2 B3 Features Operating from VCC = 2.4 V to 5.5 V Standby mode active low Output power: 3 W into 4 and 1.75 W into 8 with 10% THD+N max and 5 V power supply Output power: 2.3 W @ 5 V or 0.75 W @ 3 V into 4 with 1% THD+N max The gain of the device can be controlled via two external gain-setting resistors. Pop & click reduction circuitry provides low on/off switch noise while allowing the device to start within 5 ms. A standby function (active low) allows the reduction of current consumption to 10 nA typ. Table 1. Order codes Part number Temperature range Package Packing Marking A21SP16 -40 °C to +85 °C Lead-free flip-chip Tape & reel 62 March 2014 This is information on a product in full production. DocID026037 Rev 1 1/37 www.st.com Contents A21SP16 Contents 1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Application component information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 Electrical characteristic curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 5 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.1 Differential configuration principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.2 Gain in typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.3 Common mode feedback loop limitations . . . . . . . . . . . . . . . . . . . . . . . . 28 For example: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5.4 Low frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5.5 Decoupling of the circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5.6 Wake-up time (tWU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5.7 Shutdown time (tSTBY) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5.8 Consumption in shutdown mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5.9 Single-ended input configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5.10 Output filter considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 5.11 Different examples with summed inputs . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Example 1: Dual differential inputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Example 2: One differential input plus one single-ended input . . . . . . . . . . . . . . . 33 6 Footprint recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 7 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 2/37 DocID026037 Rev 1 A21SP16 1 Absolute maximum ratings Absolute maximum ratings Table 2. Absolute maximum ratings Symbol VCC Vin Parameter Value Unit 6 V GND to VCC V Supply voltage(1), (2) Input voltage (3) Toper Operating free-air temperature range -40 to + 85 °C Tstg Storage temperature -65 to +150 °C 150 °C 200 °C/W Tj Rthja Maximum junction temperature Thermal resistance junction to ambient Pdiss Power dissipation ESD Human body model ESD Machine model Latch-up VSTBY (4) Internally 2 kV 200 V 200 mA GND to VCC V 260 °C Latch-up immunity Standby pin voltage maximum voltage (6) limited(5) Lead temperature (soldering, 10 sec) 1. Caution: This device is not protected in the event of abnormal operating conditions, such as for example, short-circuiting between any one output pin and ground, between any one output pin and VCC, and between individual output pins. 2. All voltage values are measured with respect to the ground pin. 3. The magnitude of the input signal must never exceed VCC + 0.3V / GND - 0.3V. 4. The device is protected in case of over temperature by a thermal shutdown active @ 150°C. 5. Exceeding the power derating curves during a long period causes abnormal operation. 6. The magnitude of the standby signal must never exceed VCC + 0.3V / GND - 0.3V. Table 3. Operating conditions Symbol Parameter Value Unit 2.4 to 5.5 V 0.5 to VCC - 0.8 V 1.4 VSTBY VCC GND VSTBY 0.4 V Load resistor 4 Thermal resistance junction to ambient (5) 90 °C/W voltage(1) VCC Supply VIC Common mode input voltage range(2) VSTBY RL Rthja Standby voltage input: (3) Device ON Device OFF (4) 1. For VCC from 2.4V to 2.5V, the operating temperature range is reduced to 0°C Tamb 70°C. 2. For VCC from 2.4V to 2.5V, the common mode input range must be set at VCC/2. 3. Without any signal on VSTBY, the device will be in standby. 4. Minimum current consumption is obtained when VSTBY = GND. 5. With heat sink surface = 125mm2. DocID026037 Rev 1 3/37 37 Application component information 2 A21SP16 Application component information Table 4. Component information Component Functional description Cs Bypass supply capacitor. Install as close as possible to the A21SP16 to minimize high-frequency ripple. A 100nF ceramic capacitor should be added to enhance the power supply filtering at high frequency. Rin Input resistor to program the A21SP16 differential gain (gain = 300 k/Rin with Rin in k). Input capacitor Due to common mode feedback, these input capacitors are optional. However, they can be added to form with Rin a 1st order high pass filter with -3dB cut-off frequency = 1/(2**Rin*Cin). Figure 1. Typical application schematics Vcc B1 Vcc Vcc In+ 300k C2 Stdby GND GND Rin + C1 Differential Input In- Cs 1u B2 A1 - Internal Bias GND Out+ 150k C3 Output - InIn+ + PWM H Bridge SPEAKER Rin Input capacitors are optional A3 150k Out- Oscillator TS4962 GND B3 A2 GND GND Vcc B1 Vcc Vcc In+ 300k C2 Stdby GND GND + Rin C1 Differential Input In- - A1 Internal Bias 4 Ohms LC Output Filter GND Out+ 150k C3 15µH Output - InIn+ + PWM 2µF H Bridge Rin Input capacitors are optional GND Cs 1u B2 GND A3 150k Out- 2µF 15µH Oscillator GND TS4962 B3 A2 30µH GND 1µF GND 1µF 30µH 8 Ohms LC Output Filter 4/37 DocID026037 Rev 1 Load A21SP16 3 Electrical characteristics Electrical characteristics Table 5. VCC = +5V, GND = 0V, VIC = 2.5V, tamb = 25°C (unless otherwise specified) Symbol ICC Parameter Conditions Supply current (1) Typ. Max. Unit No input signal, no load 2.3 3.3 mA No input signal, VSTBY = GND 10 1000 nA 3 25 mV ISTBY Standby current VOO Output offset voltage No input signal, RL = 8 Output power G=6dB THD = 1% max, F = 1kHz, RL = 4 THD = 10% max, F = 1kHz, RL = 4 THD = 1% max, F = 1kHz, RL = 8 THD = 10% max, F = 1kHz, RL = 8 Pout Total harmonic THD + N distortion + noise Efficiency Efficiency Min. 2.3 3 1.4 1.75 W Pout = 900mWRMS, G = 6dB, 20Hz < F < 20kHz RL = 8W + 15µH, BW < 30kHz Pout = 1WRMS, G = 6dB, F = 1kHz, RL = 8W + 15µH, BW < 30kHz 0.4 Pout = 2WRMS, RL = 4 + 15µH Pout =1.2WRMS, RL = 8+ 15µH 78 88 % 1 % PSRR Power supply rejection ratio with inputs grounded (2) F = 217Hz, RL = 8G=6dB Vripple = 200mVpp 63 dB CMRR Common mode rejection ratio F = 217Hz, RL = 8G = 6dB, Vicm = 200mVpp 57 dB Gain value Rin in k Gain 273k -----------------R in 300k -----------------R in 327k -----------------R in V/V RSTBY Internal resistance from Standby to GND 273 300 327 k FPWM Pulse width modulator base frequency 180 250 320 kHz SNR Signal to noise ratio tWU Wake-up time 5 10 ms tSTBY Standby time 5 10 ms A-weighting, Pout = 1.2W, RL = 8 DocID026037 Rev 1 85 dB 5/37 37 Electrical characteristics A21SP16 Table 5. VCC = +5V, GND = 0V, VIC = 2.5V, tamb = 25°C (unless otherwise specified) (continued) Symbol VN Parameter Output voltage noise Conditions Min. Typ. F = 20Hz to 20kHz, G = 6dB Unweighted RL = 4 A-weighted RL = 4 85 60 Unweighted RL = 8 A-weighted RL = 8 86 62 Unweighted RL = 4 + 15µH A-weighted RL = 4 + 15µH 83 60 Unweighted RL = 4 + 30µH A-weighted RL = 4 + 30µH 88 64 Unweighted RL = 8 + 30µH A-weighted RL = 8 + 30µH 78 57 Unweighted RL = 4 + Filter A-weighted RL = 4 + Filter 87 65 Unweighted RL = 4 + Filter A-weighted RL = 4 + Filter 82 59 Max. Unit VRMS 1. Standby mode is active when VSTBY is tied to GND. 2. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the superimposed sinusoidal signal to VCC @ F = 217Hz. 6/37 DocID026037 Rev 1 A21SP16 Electrical characteristics Table 6. VCC = +4.2V, GND = 0V, VIC = 2.5V, Tamb = 25°C (unless otherwise specified)(1) Symbol ICC Parameter Supply current (2) Conditions Typ. Max. Unit No input signal, no load 2.1 3 mA No input signal, VSTBY = GND 10 1000 nA 3 25 mV ISTBY Standby current VOO Output offset voltage No input signal, RL = 8 Output power G=6dB THD = 1% max, F = 1kHz, RL = 4 THD = 10% max, F = 1kHz, RL = 4 THD = 1% max, F = 1kHz, RL = 8 THD = 10% max, F = 1kHz, RL = 8 Pout Total harmonic THD + N distortion + noise Efficiency Efficiency Min. 1.6 2 0.95 1.2 Pout = 600mWRMS, G = 6dB, 20Hz < F < 20kHz RL = 8 + 15µH, BW < 30kHz Pout = 700mWRMS, G = 6dB, F = 1kHz, RL = 8 + 15µH, BW < 30kHz W 1 % 0.35 Pout = 1.45WRMS, RL = 4 + 15µH Pout =0.9WRMS, RL = 8+ 15µH 78 88 % PSRR Power supply rejection ratio with inputs grounded (3) F = 217Hz, RL = 8G=6dB Vripple = 200mVpp 63 dB CMRR Common mode rejection ratio F = 217Hz, RL = 8G = 6dB, Vicm = 200mVpp 57 dB Gain value Rin in k Gain 273k -----------------R in 300k -----------------R in 327k -----------------R in V/V RSTBY Internal resistance from Standby to GND 273 300 327 k FPWM Pulse width modulator base frequency 180 250 320 kHz SNR Signal to noise ratio tWU Wake-uptime 5 10 ms tSTBY Standby time 5 10 ms A-weighting, Pout = 0.9W, RL = 8 DocID026037 Rev 1 85 dB 7/37 37 Electrical characteristics A21SP16 Table 6. VCC = +4.2V, GND = 0V, VIC = 2.5V, Tamb = 25°C (unless otherwise specified)(1) (continued) Symbol VN Parameter Output voltage noise Conditions Min. Typ. F = 20Hz to 20kHz, G = 6dB Unweighted RL = 4 A-weighted RL = 4 85 60 Unweighted RL = 8 A-weighted RL = 8 86 62 Unweighted RL = 4 + 15µH A-weighted RL = 4 + 15µH 83 60 Unweighted RL = 4 + 30µH A-weighted RL = 4 + 30µH 88 64 Unweighted RL = 8 + 30µH A-weighted RL = 8 + 30µH 78 57 Unweighted RL = 4 + Filter A-weighted RL = 4 + Filter 87 65 Unweighted RL = 4 + Filter A-weighted RL = 4 + Filter 82 59 Max. Unit VRMS 1. All electrical values are guaranteed with correlation measurements at 2.5 V and 5 V. 2. Standby mode is active when VSTBY is tied to GND. 3. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the superimposed sinusoidal signal to VCC @ F = 217Hz. 8/37 DocID026037 Rev 1 A21SP16 Electrical characteristics Table 7. VCC = +3.6V, GND = 0V, VIC = 2.5V, Tamb = 25°C (unless otherwise specified)(1) Symbol ICC Parameter Supply current (2) Conditions Typ. Max. Unit No input signal, no load 2 2.8 mA No input signal, VSTBY = GND 10 1000 nA 3 25 mV ISTBY Standby current VOO Output offset voltage No input signal, RL = 8 Output power G=6dB THD = 1% max, F = 1kHz, RL = 4 THD = 10% max, F = 1kHz, RL = 4 THD = 1% max, F = 1kHz, RL = 8 THD = 10% max, F = 1kHz, RL = 8 Pout Total harmonic THD + N distortion + noise Efficiency Efficiency Min. 1.15 1.51 0.7 0.9 Pout = 500mWRMS, G = 6dB, 20Hz < F< 20kHz RL = 8 + 15µH, BW < 30kHz Pout = 500mWRMS, G = 6dB, F = 1kHz, RL = 8 + 15µH, BW < 30kHz W 1 % 0.27 Pout = 1WRMS, RL = 415µH Pout =0.65WRMS, RL = 815µH 78 88 % PSRR Power supply rejection ratio with inputs grounded (3) F = 217Hz, RL = 8G=6dB Vripple = 200mVpp 62 dB CMRR Common mode rejection ratio F = 217Hz, RL = 8G = 6dB, Vicm = 200mVpp 56 dB Gain value Rin in k Gain 273k -----------------R in 300k -----------------R in 327k -----------------R in V/V RSTBY Internal resistance from Standby to GND 273 300 327 k FPWM Pulse width modulator base frequency 180 250 320 kHz SNR Signal to noise ratio tWU Wake-uptime 5 10 ms tSTBY Standby time 5 10 ms A-weighting, Pout = 0.6W, RL = 8 DocID026037 Rev 1 83 dB 9/37 37 Electrical characteristics A21SP16 Table 7. VCC = +3.6V, GND = 0V, VIC = 2.5V, Tamb = 25°C (unless otherwise specified)(1) (continued) Symbol VN Parameter Output voltage noise Conditions Min. Typ. F = 20Hz to 20kHz, G = 6dB Unweighted RL = 4 A-weighted RL = 4 83 57 Unweighted RL = 8 A-weighted RL = 8 83 61 Unweighted RL = 4 + 15µH A-weighted RL = 4+ 15µH 81 58 Unweighted RL = 4+ 30µH A-weighted RL = 4 + 30µH 87 62 Unweighted RL = 8 + 30µH A-weighted RL = 8+ 30µH 77 56 Unweighted RL = 4 + Filter A-weighted RL = 4 + Filter 85 63 Unweighted RL = 4 + Filter A-weighted RL = 4 + Filter 80 57 Max. Unit VRMS 1. All electrical values are guaranteed with correlation measurements at 2.5V and 5V. 2. Standby mode is active when VSTBY is tied to GND. 3. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the superimposed sinusoidal signal to VCC @ F = 217Hz. 10/37 DocID026037 Rev 1 A21SP16 Electrical characteristics Table 8. VCC = +3V, GND = 0V, VIC = 2.5V, Tamb = 25°C (unless otherwise specified)(1) Symbol ICC Parameter Supply current (2) Conditions Typ. Max. Unit No input signal, no load 1.9 2.7 mA No input signal, VSTBY = GND 10 1000 nA 3 25 mV ISTBY Standby current VOO Output offset voltage No input signal, RL = 8 Output power G=6dB THD = 1% max, F = 1kHz, RL = 4 THD = 10% max, F = 1kHz, RL = 4 THD = 1% max, F = 1kHz, RL = 8 THD = 10% max, F = 1kHz, RL = 8 Pout Total harmonic THD + N distortion + noise Efficiency Efficiency Min. 0.75 1 0.5 0.6 Pout = 350mWRMS, G = 6dB, 20Hz < F < 20kHz RL = 8 + 15µH, BW < 30kHz Pout = 350mWRMS, G = 6dB, F = 1kHz, RL = 8 + 15µH, BW < 30kHz W 1 % 0.21 Pout = 0.7WRMS, RL = 4 + 15µH Pout = 0.45WRMS, RL = 8+ 15µH 78 88 % PSRR Power supply rejection ratio with inputs grounded (3) F = 217Hz, RL = 8G=6dB Vripple = 200mVpp 60 dB CMRR Common mode rejection ratio F = 217Hz, RL = 8G = 6dB, Vicm = 200mVpp 54 dB Gain value Rin in k Gain 273k -----------------R in 300k -----------------R in 327k -----------------R in V/V RSTBY Internal resistance from Standby to GND 273 300 327 k FPWM Pulse width modulator base frequency 180 250 320 kHz SNR Signal to noise ratio tWU Wake-up time 5 10 ms tSTBY Standby time 5 10 ms A-weighting, Pout = 0.4W, RL = 8 DocID026037 Rev 1 82 dB 11/37 37 Electrical characteristics A21SP16 Table 8. VCC = +3V, GND = 0V, VIC = 2.5V, Tamb = 25°C (unless otherwise specified)(1) (continued) Symbol VN Parameter Output voltage noise Conditions Min. Typ. f = 20Hz to 20kHz, G = 6dB Unweighted RL = 4 A-weighted RL = 4 83 57 Unweighted RL = 8 A-weighted RL = 8 83 61 Unweighted RL = 4 + 15µH A-weighted RL = 4 + 15µH 81 58 Unweighted RL = 4 + 30µH A-weighted RL = 4 + 30µH 87 62 Unweighted RL = 8 + 30µH A-weighted RL = 8 + 30µH 77 56 Unweighted RL = 4 + Filter A-weighted RL = 4 + Filter 85 63 Unweighted RL = 4 + Filter A-weighted RL = 4 + Filter 80 57 Max. Unit VRMS 1. All electrical values are guaranteed with correlation measurements at 2.5 V and 5 V. 2. Standby mode is active when VSTBY is tied to GND. 3. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the superimposed sinusoidal signal to VCC @ F = 217Hz. 12/37 DocID026037 Rev 1 A21SP16 Electrical characteristics Table 9. VCC = +2.5V, GND = 0V, VIC = 2.5V, Tamb = 25°C (unless otherwise specified) Symbol ICC Parameter Supply current (1) Conditions Typ. Max. Unit No input signal, no load 1.7 2.4 mA No input signal, VSTBY = GND 10 1000 nA 3 25 mV ISTBY Standby current VOO Output offset voltage No input signal, RL = 8 Output power G=6dB THD = 1% max, F = 1kHz, RL = 4 THD = 10% max, F = 1kHz, RL = 4 THD = 1% max, F = 1kHz, RL = 8 THD = 10% max, F = 1kHz, RL = 8 Pout Total harmonic THD + N distortion + noise Efficiency Efficiency Min. 0.52 0.71 0.33 0.42 Pout = 200mWRMS, G = 6dB, 20Hz < F< 20kHz RL = 8 + 15µH, BW < 30kHz Pout = 200WRMS, G = 6dB, F = 1kHz, RL = 8 + 15µH, BW < 30kHz W 1 % 0.19 Pout = 0.47WRMS, RL = 4 + 15µH Pout = 0.3WRMS, RL = 8+ 15µH 78 88 % PSRR Power supply rejection ratio with inputs grounded (2) F = 217Hz, RL = 8G=6dB Vripple = 200mVpp 60 dB CMRR Common mode rejection ratio F = 217Hz, RL = 8G = 6dB, Vicm = 200mVpp 54 dB Gain value Rin in k Gain 273k -----------------R in 300k -----------------R in 327k -----------------R in V/V RSTBY Internal resistance from Standby to GND 273 300 327 k FPWM Pulse width modulator base frequency 180 250 320 kHz SNR Signal to noise ratio tWU Wake-up time 5 10 ms tSTBY Standby time 5 10 ms A-weighting, Pout = 1.2W, RL = 8 DocID026037 Rev 1 80 dB 13/37 37 Electrical characteristics A21SP16 Table 9. VCC = +2.5V, GND = 0V, VIC = 2.5V, Tamb = 25°C (unless otherwise specified) (continued) Symbol VN Parameter Output voltage noise Conditions Min. Typ. F = 20Hz to 20kHz, G = 6dB Unweighted RL = 4 A-weighted RL = 4 85 60 Unweighted RL = 8 A-weighted RL = 8 86 62 Unweighted RL = 4 + 15µH A-weighted RL = 4 + 15µH 76 56 Unweighted RL = 4 + 30µH A-weighted RL = 4 + 30µH 82 60 Unweighted RL = 8 + 30µH A-weighted RL = 8 + 30µH 67 53 Unweighted RL = 4 + Filter A-weighted RL = 4 + Filter 78 57 Unweighted RL = 4 + Filter A-weighted RL = 4 + Filter 74 54 Max. Unit VRMS 1. Standby mode is active when VSTBY is tied to GND. 2. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the superimposed sinusoidal signal to VCC @ F = 217Hz. 14/37 DocID026037 Rev 1 A21SP16 Electrical characteristics Table 10. VCC = +2.4V, GND = 0V, VIC = 2.5V, Tamb = 25°C (unless otherwise specified) Symbol ICC Parameter Supply current (1) Conditions Min. Typ. Max. Unit No input signal, no load 1.7 mA No input signal, VSTBY = GND 10 nA 3 mV ISTBY Standby current VOO Output offset voltage No input signal, RL = 8 Output power G=6dB THD = 1% max, F = 1kHz, RL = 4 THD = 10% max, F = 1kHz, RL = 4 THD = 1% max, F = 1kHz, RL = 8 THD = 10% max, F = 1kHz, RL = 8 Total harmonic distortion + noise Pout = 200mWRMS, G = 6dB, 20Hz < F< 20kHz RL = 8 + 15µH, BW < 30kHz 1 Pout = 0.38WRMS, RL = 4 + 15µH Pout = 0.25WRMS, RL = 8+ 15µH 77 86 % Common mode rejection ratio F = 217Hz, RL = 8, G = 6dB, DVicm = 200mVpp 54 dB Gain value Rin in k Pout THD + N Efficiency Efficiency CMRR Gain RSTBY Internal resistance from Standby to GND FPWM Pulse width modulator base frequency SNR Signal to noise ratio tWU tSTBY VN 0.48 0.65 0.3 0.38 W % 273k -----------------R in 300k -----------------R in 327k -----------------R in V/V 273 300 327 k 250 kHz 80 dB Wake-up time 5 ms Standby time 5 ms Output voltage noise A Weighting, Pout = 1.2W, RL = 8 F = 20Hz to 20kHz, G = 6dB Unweighted RL = 4 A-weighted RL = 4 85 60 Unweighted RL = 8 A-weighted RL = 8 86 62 Unweighted RL = 4+ 15µH A-weighted RL = 4+ 15µH 76 56 Unweighted RL = 4+ 30µH A-weighted RL = 4+ 30µH 82 60 Unweighted RL = 8+ 30µH A-weighted RL = 8 + 30µH 67 53 Unweighted RL = 4+ Filter A-weighted RL = 4+ Filter 78 57 Unweighted RL = 4+ Filter A-weighted RL = 4+ Filter 74 54 VRMS 1. Standby mode is active when VSTBY is tied to GND. DocID026037 Rev 1 15/37 37 Electrical characteristic curves 4 A21SP16 Electrical characteristic curves The graphs included in this section use the following abbreviations: RL + 15 H or 30 H = pure resistor + very low series resistance inductor Filter = LC output filter (1 µF + 30 µH for 4 and 0.5 µF + 60 µH for 8 ) All measurements done with Cs1 = 1µF and Cs2 = 100 nF except for PSRR where Cs1 is removed. Figure 2. Test diagram for measurements Vcc 1uF Cs1 100nF Cs2 + GND Cin GND Rin Out+ In+ 15uH or 30uH 150k TS4962 Cin Rin 4 or 8 Ohms 5th order or RL 50kHz low pass filter LC Filter InOut- 150k GND Audio Measurement Bandwidth < 30kHz Figure 3. Test diagram for PSRR measurements 100nF Cs2 20Hz to 20kHz Vcc GND 4.7uF GND Rin Out+ In+ 15uH or 30uH 150k TS4962 4.7uF Rin 4 or 8 Ohms or 5th order RL LC Filter InOut- 150k GND GND 5th order 50kHz low pass Reference RMS Selective Measurement Bandwidth=1% of Fmeas filter 16/37 DocID026037 Rev 1 50kHz low pass filter A21SP16 Electrical characteristic curves Figure 4. Current consumption vs. power supply voltage Figure 5. Current consumption vs. standby voltage 2.5 2.5 Current Consumption (mA) 2.0 1.5 1.0 0.5 0.0 2.0 1.5 1.0 0.5 0.0 0 1 2 3 4 5 Vcc = 5V No load Tamb=25°C 0 1 2 2.0 20 1.5 15 1.0 Vcc=5V Vcc=2.5V 10 Vcc=3.3V Vcc = 3V No load Tamb=25°C 0.5 1.0 1.5 2.0 2.5 G = 6dB Tamb = 25°C 0 0.0 0.5 1.0 1.5 3.0 Figure 8. Efficiency vs. output power 100 300 40 1.0 Output Power (W) 4.0 4.5 5.0 200 Vcc=5V RL=4Ω + ≥ 15μH 100 F=1kHz THD+N≤2% 0 1.5 2.0 200 80 150 Efficiency (%) 60 0.5 3.5 Efficiency Power Dissipation (mW) Efficiency (%) 400 20 3.0 100 500 Power Dissipation 2.5 Figure 9. Efficiency vs. output power 600 Efficiency 2.0 Common Mode Input Voltage (V) Standby Voltage (V) 0 0.0 5 5 0.5 80 4 Figure 7. Output offset voltage vs. common mode input voltage Voo (mV) Current Consumption (mA) Figure 6. Current consumption vs. standby voltage 0.0 0.0 3 Standby Voltage (V) Power Supply Voltage (V) 60 100 40 Power Dissipation 20 0 0.0 DocID026037 Rev 1 0.1 0.2 0.3 0.4 Output Power (W) Vcc=3V 50 RL=4Ω + ≥ 15μH F=1kHz THD+N≤2% 0 0.5 0.6 0.7 Power Dissipation (mW) Current Consumption (mA) No load Tamb=25°C 17/37 37 Electrical characteristic curves A21SP16 Efficiency 100 60 Power Dissipation 40 50 Vcc=5V RL=8Ω + ≥ 15μH F=1kHz THD+N≤1% 20 0 0.0 0.2 0.4 0.6 Output Power (W) 0.8 Power Dissipation (mW) 80 Efficiency (%) 100 150 50 60 40 Power Dissipation 20 0 0.0 Figure 12. Output power vs. power supply voltage 0.1 0.2 0.3 Output Power (W) 3.0 2.0 RL = 4Ω + ≥ 15μH F = 1kHz 2.5 BW < 30kHz Tamb = 25°C 2.0 RL = 8Ω + ≥ 15μH F = 1kHz BW < 30kHz 1.5 Tamb = 25°C THD+N=10% 1.5 1.0 THD+N=2% 25 Vcc=3V RL=8Ω + ≥ 15μH F=1kHz THD+N≤1% 0 0.5 0.4 Figure 13. Output power vs. power supply voltage Output power (W) Output power (W) Efficiency 0 1.0 75 80 Efficiency (%) 100 Figure 11. Efficiency vs. output power Power Dissipation (mW) Figure 10. Efficiency vs. output power THD+N=10% 1.0 0.5 THD+N=1% 0.5 0.0 0.0 2.5 3.0 3.5 4.0 Vcc (V) 4.5 5.0 Figure 14. PSRR vs. frequency 3.0 5.0 -30 -20 -40 Vcc=3V -50 Vripple = 200mVpp Inputs = Grounded G = 6dB, Cin = 4.7μF RL = 4Ω + 30μH Tamb = 25°C -10 PSRR (dB) -20 -60 -30 -40 Vcc=3V -50 -60 -70 -70 Vcc=5V 18/37 4.5 0 Vripple = 200mVpp Inputs = Grounded G = 6dB, Cin = 4.7μF RL = 4Ω + 15μH Tamb = 25°C -10 -80 3.5 4.0 Vcc (V) Figure 15. PSRR vs. frequency 0 PSRR (dB) 2.5 20 100 1000 Frequency (Hz) Vcc=5V 10000 20k -80 20 DocID026037 Rev 1 100 1000 Frequency (Hz) 10000 20k A21SP16 Electrical characteristic curves Figure 16. PSRR vs. frequency Figure 17. PSRR vs. frequency 0 0 Vripple = 200mVpp Inputs = Grounded G = 6dB, Cin = 4.7μF RL = 4Ω + Filter Tamb = 25°C PSRR (dB) -20 -30 -20 -40 Vcc=3V -50 Vripple = 200mVpp Inputs = Grounded G = 6dB, Cin = 4.7μF RL = 8Ω + 15μH Tamb = 25°C -10 PSRR (dB) -10 -30 -40 Vcc=3V -50 -60 -60 -70 -70 Vcc=5V Vcc=5V -80 -80 20 100 10000 20k 1000 Frequency (Hz) 20 Figure 18. PSRR vs. frequency -30 -20 -40 Vcc=3V -50 Vripple = 200mVpp Inputs = Grounded G = 6dB, Cin = 4.7μF RL = 8Ω + Filter Tamb = 25°C -10 PSRR (dB) -20 -30 -40 Vcc=3V -50 -60 -60 -70 -70 Vcc=5V Vcc=5V -80 20 100 10000 20k 1000 Frequency (Hz) 20 Figure 20. PSRR vs. common mode input voltage -10 -20 100 1000 Frequency (Hz) 10000 20k Figure 21. CMRR vs. frequency 0 0 Vripple = 200mVpp F = 217Hz, G = 6dB RL ≥ 4Ω + ≥ 15μH Tamb = 25°C RL=4Ω + 15μH G=6dB ΔVicm=500mVpp Cin=4.7μF Tamb = 25°C Vcc=2.5V -20 -30 CMRR (dB) PSRR(dB) 10000 20k 0 Vripple = 200mVpp Inputs = Grounded G = 6dB, Cin = 4.7μF RL = 8Ω + 30μH Tamb = 25°C -10 -80 1000 Frequency (Hz) Figure 19. PSRR vs. frequency 0 PSRR (dB) 100 Vcc=3.3V -40 -40 -50 Vcc=5V, 3V -60 -60 -70 Vcc=5V -80 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 20 Common Mode Input Voltage (V) DocID026037 Rev 1 100 1000 Frequency (Hz) 10000 20k 19/37 37 Electrical characteristic curves A21SP16 Figure 22. CMRR vs. frequency Figure 23. CMRR vs. frequency 0 0 RL=4Ω + 30μH G=6dB ΔVicm=500mVpp Cin=4.7μF Tamb = 25°C -40 -20 CMRR (dB) CMRR (dB) -20 RL=4Ω + Filter G=6dB ΔVicm=500mVpp Cin=4.7μF Tamb = 25°C -40 Vcc=5V, 3V Vcc=5V, 3V -60 -60 20 100 1000 Frequency (Hz) 20 10000 20k Figure 24. CMRR vs. frequency 100 10000 20k 1000 Frequency (Hz) Figure 25. CMRR vs. frequency 0 0 RL=8Ω + 15μH G=6dB ΔVicm=500mVpp Cin=4.7μF Tamb = 25°C -40 -20 CMRR (dB) CMRR (dB) -20 RL=8Ω + 30μH G=6dB ΔVicm=500mVpp Cin=4.7μF Tamb = 25°C -40 Vcc=5V, 3V Vcc=5V, 3V -60 -60 20 100 1000 Frequency (Hz) 20 10000 20k Figure 26. CMRR vs. frequency 100 10000 20k 1000 Frequency (Hz) Figure 27. CMRR vs. common mode input voltage -20 0 RL=8Ω + Filter G=6dB ΔVicm=500mVpp Cin=4.7μF Tamb = 25°C -40 CMRR(dB) CMRR (dB) -20 -30 Vcc=5V, 3V -40 ΔVicm = 200mVpp F = 217Hz G = 6dB RL ≥ 4Ω + ≥ 15μH Tamb = 25°C Vcc=2.5V -50 Vcc=3.3V -60 -60 Vcc=5V 20 20/37 100 1000 Frequency (Hz) 10000 20k -70 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Common Mode Input Voltage (V) DocID026037 Rev 1 4.5 5.0 A21SP16 Electrical characteristic curves Figure 28. THD+N vs. output power 10 10 RL = 4Ω + 30μH F = 1kHz G = 6dB BW < 30kHz Tamb = 25°C Vcc=4V THD + N (%) RL = 4Ω + 15μH F = 1kHz G = 6dB BW < 30kHz Tamb = 25°C THD + N (%) Figure 29. THD+N vs. output power Vcc=2.5V 1 Vcc=4V Vcc=2.5V 1 0.1 0.1 1E-3 0.01 0.1 Output Power (W) 1E-3 1 0.01 0.1 Output Power (W) 1 Figure 31. THD+N vs. output power 10 10 RL = 8Ω + 15μH F = 1kHz G = 6dB BW < 30kHz Tamb = 25°C RL = 8Ω + Filter F = 1kHz G = 6dB BW < 30kHz Tamb = 25°C Vcc=5V Vcc=3.3V THD + N (%) THD + N (%) Figure 30. THD+N vs. output power Vcc=2.5V 1 Vcc=5V Vcc=3.3V Vcc=2.5V 1 0.1 0.1 1E-3 0.01 0.1 Output Power (W) 1E-3 1 0.01 0.1 Output Power (W) 1 Figure 33. THD+N vs. output power 10 10 RL = 4Ω + 15μH F = 1kHz G = 6dB BW < 30kHz Tamb = 25°C Vcc=2.5V 1 Vcc=4V Vcc=2.5V 1 0.1 0.1 1E-3 RL = 4Ω + 30μH F = 1kHz G = 6dB BW < 30kHz Tamb = 25°C Vcc=4V THD + N (%) THD + N (%) Figure 32. THD+N vs. output power 0.01 0.1 Output Power (W) 1 1E-3 DocID026037 Rev 1 0.01 0.1 Output Power (W) 1 21/37 37 Electrical characteristic curves A21SP16 Figure 35. THD+N vs. output power 10 10 RL = 8Ω + 15μH F = 1kHz G = 6dB BW < 30kHz Tamb = 25°C RL = 8Ω + Filter F = 1kHz G = 6dB BW < 30kHz Tamb = 25°C Vcc=5V Vcc=3.3V THD + N (%) THD + N (%) Figure 34. THD+N vs. output power Vcc=2.5V 1 1E-3 0.01 0.1 Output Power (W) 1E-3 1 Figure 36. THD+N vs. frequency 1 10 RL=8Ω + 15μH G=6dB Bw < 30kHz Vcc=5V Tamb = 25°C Po=0.9W THD + N (%) THD + N (%) 0.01 0.1 Output Power (W) Figure 37. THD+N vs. frequency 10 1 0.1 1000 Frequency (Hz) RL=8Ω + Filter G=6dB Bw < 30kHz Vcc=5V Tamb = 25°C Po=0.9W 1 0.1 Po=0.45W 200 10000 20k Po=0.45W 200 Figure 38. THD+N vs. frequency 1000 Frequency (Hz) 10000 20k Figure 39. THD+N vs. frequency 10 10 RL=4Ω + 15μH G=6dB Bw < 30kHz Vcc=3.6V Tamb = 25°C 1 200 1000 Frequency (Hz) 10000 20k Po=0.7W 1 Po=0.35W 0.1 Po=0.35W 0.1 RL=4Ω + 30μH G=6dB Bw < 30kHz Vcc=3.6V Tamb = 25°C Po=0.7W THD + N (%) THD + N (%) Vcc=2.5V 1 0.1 0.1 22/37 Vcc=5V Vcc=3.3V 200 DocID026037 Rev 1 1000 Frequency (Hz) 10000 20k A21SP16 Electrical characteristic curves Figure 40. THD+N vs. frequency Figure 41. THD+N vs. frequency 10 10 THD + N (%) 1 RL=4Ω + Filter G=6dB Bw < 30kHz Vcc=2.5V Tamb = 25°C Po=0.3W 1 0.1 THD + N (%) RL=4Ω + 15μH G=6dB Bw < 30kHz Vcc=2.5V Tamb = 25°C Po=0.1W Po=0.3W 0.1 Po=0.1W 200 1000 Frequency (Hz) 10000 20k 0.01 Figure 42. THD+N vs. frequency 100 150 Efficiency Po=0.9W 1 100 60 Power Dissipation 40 50 Vcc=5V RL=8Ω + ≥ 15μH F=1kHz THD+N≤1% 20 0.1 Po=0.45W 1000 Frequency (Hz) 200 10000 0 0.0 20k Figure 44. THD+N vs. frequency 0.2 0.8 1.0 0 10 RL=8Ω + 30μH G=6dB Bw < 30kHz Vcc=3.6V Tamb = 25°C Po=0.5W 1 THD + N (%) RL=8Ω + 15μH G=6dB Bw < 30kHz Vcc=3.6V Tamb = 25°C 0.1 Po=0.25W 0.01 200 1000 Frequency (Hz) Po=0.5W 0.1 Po=0.25W 0.01 0.4 0.6 Output Power (W) Figure 45. THD+N vs. frequency 10 1 20k 80 Efficiency (%) RL=8Ω + 15μH G=6dB Bw < 30kHz Vcc=5V Tamb = 25°C THD + N (%) 10000 Figure 43. THD+N vs. frequency 10 THD + N (%) 1000 Frequency (Hz) 200 Power Dissipation (mW) 0.01 10000 20k 200 DocID026037 Rev 1 1000 Frequency (Hz) 10000 20k 23/37 37 Electrical characteristic curves A21SP16 Figure 46. THD+N vs. frequency Figure 47. THD+N vs. frequency 10 10 THD + N (%) 1 RL=8Ω + Filter G=6dB Bw < 30kHz Vcc=2.5V Tamb = 25°C Po=0.2W 1 THD + N (%) RL=8Ω + 15μH G=6dB Bw < 30kHz Vcc=2.5V Tamb = 25°C 0.1 Po=0.2W 0.1 Po=0.1W 0.01 200 1000 Frequency (Hz) Po=0.1W 10000 20k 0.01 8 8 6 6 Vcc=5V, 3V RL=4Ω + 15μH G=6dB Vin=500mVpp Cin=1μF Tamb = 25°C 2 0 100 1000 Frequency (Hz) 10000 20k RL=4Ω + 30μH G=6dB Vin=500mVpp Cin=1μF Tamb = 25°C 2 20 100 8 8 6 6 0 24/37 Vcc=5V, 3V RL=4Ω + Filter G=6dB Vin=500mVpp Cin=1μF Tamb = 25°C 2 100 1000 Frequency (Hz) 10000 20k Vcc=5V, 3V 4 10000 20k RL=8Ω + 15μH G=6dB Vin=500mVpp Cin=1μF Tamb = 25°C 2 0 20 1000 Frequency (Hz) Figure 51. Gain vs. frequency Differential Gain (dB) Differential Gain (dB) Figure 50. Gain vs. frequency 4 20k Vcc=5V, 3V 4 0 20 10000 Figure 49. Gain vs. frequency Differential Gain (dB) Differential Gain (dB) Figure 48. Gain vs. frequency 4 1000 Frequency (Hz) 200 20 DocID026037 Rev 1 100 1000 Frequency (Hz) 10000 20k A21SP16 Electrical characteristic curves Figure 53. Gain vs. frequency 8 8 6 6 Differential Gain (dB) Differential Gain (dB) Figure 52. Gain vs. frequency Vcc=5V, 3V 4 RL=8Ω + 30μH G=6dB Vin=500mVpp Cin=1μF Tamb = 25°C 2 0 Vcc=5V, 3V 4 0 20 100 1000 Frequency (Hz) 10000 20k Figure 54. Gain vs. frequency RL=8Ω + Filter G=6dB Vin=500mVpp Cin=1μF Tamb = 25°C 2 20 100 1000 Frequency (Hz) 10000 20k Figure 55. Startup & shutdown time VCC = 5 V, G = 6 dB, Cin = 1 µF (5 ms/div) 8 Differential Gain (dB) Vo1 6 Vo2 Vcc=5V, 3V 4 Standby RL=No Load G=6dB Vin=500mVpp Cin=1μF Tamb = 25°C 2 0 20 100 Vo1-Vo2 1000 Frequency (Hz) 10000 20k Figure 56. Startup & shutdown time VCC = 3V, G = 6 dB, Cin = 1 µF (5 ms/div) Figure 57. Startup & shutdown time VCC = 5V , G = 6 dB, Cin = 100 nF (5 ms/div) Vo1 Vo1 Vo2 Vo2 Standby Standby Vo1-Vo2 Vo1-Vo2 DocID026037 Rev 1 25/37 37 Electrical characteristic curves A21SP16 Figure 58. Startup & shutdown time VCC = 3 V, G = 6 dB, Cin = 100 nF (5 ms/div) Figure 59. Startup & shutdown time VCC = 5 V, G = 6 dB, No Cin (5 ms/div) Vo1 Vo1 Vo2 Vo2 Standby Standby Vo1-Vo2 Vo1-Vo2 Figure 60. Startup & shutdown time VCC = 3 V, G = 6 dB, No Cin (5 ms/div) Vo1 Vo2 Standby Vo1-Vo2 26/37 DocID026037 Rev 1 A21SP16 Application information 5 Application information 5.1 Differential configuration principle The A21SP16 is a monolithic fully-differential input/output class D power amplifier. The A21SP16 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, maximizes 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: High PSRR (power supply rejection ratio). High common mode noise rejection. Virtually zero pop without additional circuitry, giving a faster start-up 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. The main disadvantage is: 5.2 As the differential function is directly linked to external resistor mismatching, paying particular attention to this mismatching is mandatory in order to obtain the best performance from the amplifier. Gain in typical application schematic Typical differential applications are shown in Figure 1 on page 4. In the flat region of the frequency-response curve (no input coupling capacitor effect), the differential gain is expressed by the relation: + AV diff - Out – Out 300 = ------------------------------ = ---------+ R in In – In with Rin expressed in k Due to the tolerance of the internal 150 k feedback resistor, the differential gain will be in the range (no tolerance on Rin): 327 273 ---------- A V ---------diff R in R in DocID026037 Rev 1 27/37 37 Application information 5.3 A21SP16 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 in the input stage (see Table 3: Operating conditions on page 3), the common mode feedback loop can ensure its role only within a defined range. This range depends upon the values of VCC and Rin (AVdiff). To have a good estimation of the Vicm value, we can apply this formula (no tolerance on Rin): V CC R in + 2 V IC 150k V icm = ---------------------------------------------------------------------------2 R in + 150k (V) with + - In + In V IC = --------------------2 (V) and the result of the calculation must be in the range: 0.5V V icm V CC – 0.8V Due to the +/-9% tolerance on the 150k resistor, it’s also important to check Vicm in these conditions: V CC R in + 2 V IC 136.5k V CC R in + 2 V IC 163.5k --------------------------------------------------------------------------------- V icm --------------------------------------------------------------------------------2 R in + 136.5k 2 R in + 163.5k If the result of Vicm calculation is not in the previous range, input coupling capacitors must be used (with VCC from 2.4 V to 2.5 V, input coupling capacitors are mandatory). For example: With VCC = 3 V, Rin = 150 k and VIC = 2.5 V, we typically find Vicm = 2 V and this is lower than 3V - 0.8 V = 2.2 V. With 136.5 k we find 1.97 V, and with 163.5 k we have 2.02 V. So, no input coupling capacitors are required. 5.4 Low frequency response If a low frequency bandwidth limitation is requested, it is possible to use input coupling capacitors. In the low frequency region, Cin (input coupling capacitor) starts to have an effect. Cin forms, with Rin, a first order high-pass filter with a -3dB cut-off frequency: 1 F CL = -----------------------------------2 R in C in (Hz) So, for a desired cut-off frequency we can calculate Cin, 1 C in = -------------------------------------2 R in F CL with Rin in and FCL in Hz. 28/37 DocID026037 Rev 1 (F) A21SP16 5.5 Application information Decoupling of the circuit A power supply capacitor, referred to as CS, is needed to correctly bypass the A21SP16. The A21SP16 has a typical switching frequency at 250 kHz and output fall and rise time about 5 ns. Due to these very fast transients, careful decoupling is mandatory. A 1 µF ceramic capacitor is enough, but it must be located very close to the A21SP16 in order to avoid any extra parasitic inductance created an overly long track wire. In relation with dI/dt, this parasitic inductance introduces an overvoltage that decreases the global efficiency and, if it is too high, may cause a breakdown of the device. In addition, even if a ceramic capacitor has an adequate high frequency ESR value, its current capability is also important. A 0603 size is a good compromise, particularly when a 4 load is used. Another important parameter is the rated voltage of the capacitor. A 1 µF/6.3 V capacitor used at 5 V, loses about 50% of its value. In fact, with a 5 V power supply voltage, the decoupling value is about 0.5 µF instead of 1 µF. As CS has particular influence on the THD+N in the medium-high frequency region, this capacitor variation becomes decisive. In addition, less decoupling means higher overshoots, which can be problematic if they reach the power supply AMR value (6 V). 5.6 Wake-up time (tWU) When the standby is released to set the device ON, there is a wait of about 5 ms. The A21SP16 has an internal digital delay that mutes the outputs and releases them after this time in order to avoid any pop noise. 5.7 Shutdown time (tSTBY) When the standby command is set, the time required to put the two output stages into high impedance and to put the internal circuitry in shutdown mode, is about 5 ms. This time is used to decrease the gain and avoid any pop noise during shutdown. 5.8 Consumption in shutdown mode Between the shutdown pin and GND there is an internal 300 k resistor. This resistor forces the A21SP16 to be in standby mode when the standby input pin is left floating. However, this resistor also introduces additional power consumption if the shutdown pin voltage is not 0 V. For example, with a 0.4 V standby voltage pin, Table 3: Operating conditions on page 3, shows that you must add 0.4 V/300 k = 1.3 µA in typical (0.4 V/273 k = 1.46 µA in maximum) to the shutdown current specified in Table 5 on page 5. 5.9 Single-ended input configuration It is possible to use the A21SP16 in a single-ended input configuration. However, input coupling capacitors are needed in this configuration. The schematic in Figure 61 shows a single-ended input typical application. DocID026037 Rev 1 29/37 37 Application information A21SP16 Figure 61. Single-ended input typical application Vcc B1 Cs 1u B2 Vcc Standby Cin GND Rin C2 Stdby 300k Ve C1 A1 Internal Bias GND Out+ 150k C3 Output - InIn+ + H Bridge PWM SPEAKER Rin Cin A3 150k Out- Oscillator GND TS4962 GND A2 B3 GND All formulas are identical except for the gain (with Rin in k: AV sin gle Ve 300 = ------------------------------- = ---------+ R in Out – Out And, due to the internal resistor tolerance we have: 327 273 ---------- A V ---------sin gle R in R in In the event that multiple single-ended inputs are summed, it is important that the impedance on both A21SP16 inputs (In- and In+) are equal. Figure 62. Typical application schematic with multiple single-ended inputs Vcc Vek Standby B1 C2 Stdby GND Ve1 Cin1 Rin1 C1 A1 GND Ceq GND Cs 1u B2 Vcc Rink 300k Cink Internal Bias GND Out+ 150k C3 Output - InIn+ + PWM H Bridge SPEAKER Req A3 150k Out- Oscillator TS4962 GND A2 B3 GND 30/37 DocID026037 Rev 1 A21SP16 Application information We have the following equations: + 300 300 Out – Out = V e1 ------------- + + V ek ------------R ink R in1 (V) k C eq = C inj Cinj j=1 1 = ---------------------------------------------------2R F inj CLj (F) 1 R eq = ------------------k 1 --------Rinj j =1 In general, for mixed situations (single-ended and differential inputs), it is best to use the same rule, that is, to equalize impedance on both A21SP16 inputs. 5.10 Output filter considerations The A21SP16 is designed to operate without an output filter. However, due to very sharp transients on the A21SP16 output, EMI radiated emissions may cause some standard compliance issues. These EMI standard compliance issues can appear if the distance between the A21SP16 outputs and loudspeaker terminal is long (typically more than 50 mm, or 100 mm in both directions, to the speaker terminals). As the PCB layout and internal equipment device are different for each configuration, it is difficult to provide a one-size-fits-all solution. However, to decrease the probability of EMI issues, there are several simple rules to follow: Reduce, as much as possible, the distance between the A21SP16 output pins and the speaker terminals. Use ground planes for “shielding” sensitive wires. Place, as close as possible to the A21SP16 and in series with each output, a ferrite bead with a rated current at minimum 2 A and impedance greater than 50 at frequencies above 30 MHz. If, after testing, these ferrite beads are not necessary, replace them by a short-circuit. Murata BLM18EG221SN1 or BLM18EG121SN1 are possible examples of devices you can use. Allow enough footprint to place, if necessary, a capacitor to short perturbations to ground (see the schematics in Figure 63). Figure 63. Method for shorting pertubations to ground Ferrite chip bead To speaker From TS4962 output about 100pF Gnd In the case where the distance between the A21SP16 outputs and speaker terminals is high, it is possible to have low frequency EMI issues due to the fact that the typical operating frequency is 250 kHz. In this configuration, we recommend using an output filter (as shown DocID026037 Rev 1 31/37 37 Application information A21SP16 in Figure 1: Typical application schematics on page 4). It should be placed as close as possible to the device. 5.11 Different examples with summed inputs Example 1: Dual differential inputs Figure 64. Typical application schematic with dual differential inputs Vcc Standby B1 Cs 1u B2 Vcc C2 Stdby 300k R2 E2+ R1 E1+ E1- C1 A1 Internal Bias GND Out+ 150k C3 Output - InIn+ + PWM H Bridge SPEAKER R1 A3 150k E2R2 Out- Oscillator GND A2 B3 TS4962 GND With (Ri in k): + - + - Out – Out 300 A V = ------------------------------ = ---------+ 1 R1 E1 – E1 Out – Out 300 - = ---------A V = -----------------------------+ 2 R2 E2 – E2 V CC R 1 R 2 + 300 V IC1 R 2 + V IC2 R 1 0.5V --------------------------------------------------------------------------------------------------------------------------- V CC – 0.8V 300 R 1 + R 2 + 2 R 1 R 2 + - + - E1 + E1 E2 + E2 V IC = ------------------------ and V IC = -----------------------1 2 2 2 32/37 DocID026037 Rev 1 A21SP16 Application information Example 2: One differential input plus one single-ended input Figure 65. Typical application schematic with one differential input plus one singleended input Vcc Standby B1 Cs 1u B2 Vcc C2 Stdby 300k R2 E2+ C1 R1 E1+ E2- C1 A1 Internal Bias C3 Output - InIn+ + PWM H Bridge SPEAKER R2 A3 150k GND C1 R1 GND Out+ 150k Out- Oscillator GND A2 B3 TS4962 GND With (Ri in k): + - + - 300 Out – Out A V = ------------------------------ = ---------+ 1 R1 E1 Out – Out 300 A V = ------------------------------ = ---------+ 2 R2 E2 – E2 1 C 1 = -----------------------------------2 R 1 F CL DocID026037 Rev 1 (F) 33/37 37 Footprint recommendations 6 A21SP16 Footprint recommendations Figure 66. Footprint recommendations 500m 75µm min. 100m max. 500m =250m =400m typ. 150m min. =340m min. 500m 500m Track Non Solder mask opening Pad in Cu 18m with Flash NiAu (2-6m, 0.2m max.) 34/37 DocID026037 Rev 1 A21SP16 7 Package information Package information In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions and product status are available at: www.st.com. ECOPACK® is an ST trademark. Figure 67. Pin-out for 9-bump flip-chip (top view) IN+ GND OUT- 1/A1 2/A2 3/A3 VDD VDD GND Bumps are underneath 4/B1 5/B2 6/B3 Bump diameter = 300m IN- STBY OUT+ 8/C2 9/C3 7/C1 Figure 68. Marking for 9-bump flip-chip (top view) ST Logo E Symbol for lead-free: E Two first XX product code: W2 third X: Assembly code XXX Three digits date code: Y for year - WW for week YWW The dot is for marking pin A1 Figure 69. Mechanical data for 9-bump flip-chip 1.60 mm 1.60 mm 0.5mm 0.5mm 0.25mm Die size: 1.6 mm x 1.6 mm ±30m Die height (including bumps): 600 m Bump diameter: 315m 50 m Bump diameter before reflow: 300 m 10 m Bump height: 250 m ±40 m Die height: 350 m ±20 m Pitch: 500m 50 m Coplanarity: 50 m max 600µm DocID026037 Rev 1 35/37 37 Revision history 8 A21SP16 Revision history Table 11. Document revision history 36/37 Date Revision 06-Mar-2014 1 Changes Initial release. DocID026037 Rev 1 A21SP16 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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