TS4962 2.8 W filter-free mono class D audio power amplifier Features DFN8 3 x 3 mm ■ Operating from VCC = 2.4 V to 5.5 V ■ Standby mode active low ■ Output power: 2.8 W into 4 Ω and 1.7 W into 8 Ω with 10% THD+N maximum and 5 V power supply ■ Output power: 2.2 W at 5 V or 0.7 W at 3.0 V into 4 Ω with 1% THD+N maximum ■ Output power: 1.4 W at 5 V or 0.5 W at 3.0 V into 8 Ω with 1% THD+N maximum ■ Adjustable gain via external resistors ■ Low current consumption 2 mA at 3 V ■ Efficiency: 88% typical ■ Signal to noise ratio: 85 dB typical ■ PSRR: 63 dB typical at 217 Hz with 6 dB gain ■ PWM base frequency: 280 kHz ■ Low pop & click noise 2 EXPOSED 7 ■ Thermal shutdown protection 3 PAD 6 ■ Available in DFN8 3 x 3 mm package TS4962IQT pinout 8 1 4 5 Applications ■ Cellular phones ■ PDAs ■ Notebook PCs Description The TS4962 is a differential class-D BTL power amplifier. It can drive up to 2.2 W into a 4 Ω load and 1.4 W into an 8 Ω load at 5 V. It achieves outstanding efficiency (88% typ.) compared to standard AB-class audio amps. January 2010 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) enables the current consumption to be reduced to 10 nA typical. Doc ID 10968 Rev 8 1/44 www.st.com 44 Contents TS4962 Contents 1 Absolute maximum ratings and operating conditions . . . . . . . . . . . . . 3 2 Application overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.1 4 Electrical characteristics curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 4.1 Differential configuration principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 4.2 Gain in typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 4.3 Common-mode feedback loop limitations . . . . . . . . . . . . . . . . . . . . . . . . 31 4.4 Low frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 4.5 Decoupling of the circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 4.6 Wake-up time (tWU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 4.7 Shutdown time (tSTBY) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 4.8 Consumption in standby mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 4.9 Single-ended input configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 4.10 Output filter considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 4.11 Several examples with summed inputs . . . . . . . . . . . . . . . . . . . . . . . . . . 35 4.11.1 Example 1: dual differential inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 4.11.2 Example 2: one differential input plus one single-ended input . . . . . . . . 36 5 Demonstration board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 6 Recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 7 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 8 Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 2/44 Doc ID 10968 Rev 8 TS4962 1 Absolute maximum ratings and operating conditions Absolute maximum ratings and operating conditions Table 1. Absolute maximum ratings Symbol Parameter Supply voltage(1) (2) VCC Vi Input voltage (3) 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 Maximum junction temperature 150 °C Thermal resistance junction to ambient DFN8 package 120 °C/W Tj Rthja Pd Internally limited (4) Power dissipation Human body model(5) Machine ESD model(6) Charged device model Latch-up kV 200 V 200 mA GND to VCC V 260 °C (7) Latch-up immunity Standby pin maximum voltage VSTBY 2 (8) Lead temperature (soldering, 10sec) 1. Caution: this device is not protected in the event of abnormal operating conditions such as short-circuiting between any one output pin and ground or 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 + 0.3 V/GND - 0.3 V. 4. Exceeding the power derating curves during a long period will provoke abnormal operation. 5. Human body model: a 100 pF capacitor is charged to the specified voltage, then discharged through a 1.5 kΩ resistor between two pins of the device. This is done for all couples of connected pin combinations while the other pins are floating. 6. Machine model: a 200 pF capacitor is charged to the specified voltage, then discharged directly between two pins of the device with no external series resistor (internal resistor < 5 Ω). This is done for all couples of connected pin combinations while the other pins are floating. 7. Charged device model: all pins and the package are charged together to the specified voltage and then discharged directly to the ground through only one pin. This is done for all pins. 8. The magnitude of the standby signal must never exceed VCC + 0.3 V/GND - 0.3 V. Table 2. Dissipation ratings Package Derating factor Power rating at 25°C Power rating at 85°C DFN8 20 mW/°C 2.5 W 1.3 W Doc ID 10968 Rev 8 3/44 Absolute maximum ratings and operating conditions Table 3. Operating conditions Symbol VCC VIC VSTBY RL Rthja TS4962 Parameter Supply voltage (1) Common mode input voltage range (2) Standby voltage input: (3) Device ON Device OFF Value Unit 2.4 to 5.5 V 0.5 to VCC-0.8 V 1.4 ≤ VSTBY ≤ VCC GND ≤ VSTBY ≤ 0.4 (4) Load resistor ≥4 Ω Thermal resistance junction to ambient DFN8 package (5) 50 °C/W 1. For VCC between 2.4 V and 2.5 V, the operating temperature range is reduced to 0°C ≤Tamb 2. For VCC between 2.4V and 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. 4/44 V When mounted on a 4-layer PCB. Doc ID 10968 Rev 8 ≤ 70°C. TS4962 2 Application overview Application overview Table 4. External component information Component Functional description CS Bypass supply capacitor. Install as close as possible to the TS4962 to minimize high-frequency ripple. A 100 nF ceramic capacitor should be added to enhance the power supply filtering at high frequencies. Rin Input resistor used to program the TS4962’s differential gain (gain = 300 kΩ/Rin with Rin in kΩ). Input capacitor Table 5. Because of common-mode feedback, these input capacitors are optional. However, they can be added to form with Rin a 1st order high-pass filter with -3 dB cut-off frequency = 1/(2*π*Rin*Cin). Pin description Pin number Pin name 1 STBY 2 NC No internal connection pin 3 IN+ Positive input pin 4 IN- Negative input pin 5 OUT+ Positive output pin 6 VCC Power supply input pin 7 GND Ground input pin 8 OUT- Negative output pin Exposed pad Description Standby input pin (active low) Exposed pad can be connected to ground (pin 7) or left floating Doc ID 10968 Rev 8 5/44 Application overview Figure 1. TS4962 Typical application schematics Vcc 6 Vcc Cs 1u Vcc In+ 300k 1 Stdby GND Rin GND + Differential Input 4 InIn+ 3 - Rin Input capacitors are optional In- Internal Bias Out+ 150k GND 5 Output - H PWM + Bridge SPEAKER 8 150k Out- Oscillator GND GND 7 GND Vcc 6 Vcc In+ 300k 1 Stdby GND GND + Differential Input In- - Rin 4 3 Internal Bias 4 Ohms LC Output Filter GND Out+ 150k 5 15µH Output - InIn+ + PWM 2µF H GND Bridge Rin Input capacitors are optional GND Cs 1u Vcc 8 150k Out- 2µF 15µH Oscillator GND 7 30µH GND 1µF GND 1µF 30µH 8 Ohms LC Output Filter 6/44 Doc ID 10968 Rev 8 Load TS4962 3 Electrical characteristics Electrical characteristics Table 6. Electrical characteristics at VCC = +5 V, with GND = 0 V, Vicm = 2.5 V, and Tamb = 25°C (unless otherwise specified) Symbol Typ. Max. Unit Supply current No input signal, no load 2.3 3.3 mA Standby current (1) No input signal, VSTBY = GND 10 1000 nA Voo Output offset voltage No input signal, RL = 8 Ω 3 25 mV Pout Output power, G = 6 dB THD = 1% max, f = 1 kHz, RL = 4 Ω THD = 10% max, f = 1 kHz, RL = 4 Ω THD = 1% max, f = 1 kHz, RL = 8 Ω THD = 10% max, f = 1 kHz, RL = 8 Ω ICC ISTBY Parameter Min. 2.2 2.8 1.4 1.7 Total harmonic distortion + noise Pout = 850 mWRMS, G = 6 dB, 20 Hz < f < 20 kHz THD + N RL = 8 Ω + 15 µH, BW < 30 kHz Pout = 1 WRMS, G = 6 dB, f = 1 kHz RL = 8 Ω + 15 µH, BW < 30 kHz Efficiency W 2 % 0.4 Efficiency Pout = 2 WRMS, RL = 4 Ω + ≥ 15 µH Pout = 1.2 WRMS, RL = 8 Ω+ ≥ 15 µH 78 88 % PSRR Power supply rejection ratio with inputs grounded (2) f = 217 Hz, RL = 8 Ω, G = 6 dB, Vripple = 200 mVpp 63 dB CMRR Common mode rejection ratio f = 217 Hz, RL = 8 Ω, G = 6 dB, ΔVic = 200 mVpp 57 dB Gain Gain value (Rin in kΩ) 273k Ω ----------------R in 300k Ω ----------------R in 327k Ω ----------------R in V/V RSTBY Internal resistance from standby to GND 273 300 327 kΩ FPWM Pulse width modulator base frequency 200 280 360 kHz SNR Signal to noise ratio (A weighting), Pout = 1.2 W, RL = 8 Ω 85 tWU Wake-up time 5 10 ms tSTBY Standby time 5 10 ms Doc ID 10968 Rev 8 dB 7/44 Electrical characteristics Table 6. TS4962 Electrical characteristics at VCC = +5 V, with GND = 0 V, Vicm = 2.5 V, and Tamb = 25°C (unless otherwise specified) (continued) Symbol Parameter VN Output voltage noise f = 20 Hz to 20 kHz, G = 6 dB Min. Typ. Unweighted RL = 4 Ω A-weighted RL = 4 Ω 85 60 Unweighted RL = 8 Ω A-weighted RL = 8 Ω 86 62 Unweighted RL = 4 Ω + 15 µH A-weighted RL = 4 Ω + 15 µH 83 60 Unweighted RL = 4 Ω + 30 µH A-weighted RL = 4 Ω + 30 µH 88 64 Unweighted RL = 8 Ω + 30 µH A-weighted RL = 8 Ω + 30 µH 78 57 Unweighted RL = 4 Ω + filter A-weighted RL = 4 Ω + filter Unweighted RL = 4 Ω + filter A-weighted RL = 4 Ω + filter 87 65 82 59 Max. Unit μVRMS 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 at f = 217 Hz. 8/44 Doc ID 10968 Rev 8 TS4962 Electrical characteristics Table 7. Electrical characteristics at VCC = +4.2 V with GND = 0 V, Vicm = 2.1 V and Tamb = 25°C (unless otherwise specified)(1) Symbol Typ. Max. Unit Supply current No input signal, no load 2.1 3 mA Standby current (2) No input signal, VSTBY = GND 10 1000 nA Voo Output offset voltage No input signal, RL = 8 Ω 3 25 mV Pout Output power, G = 6 dB THD = 1% max, f = 1 kHz, RL = 4 Ω THD = 10% max, f = 1 kHz, RL = 4 Ω THD = 1% max, f = 1 kHz, RL = 8 Ω THD = 10% max, f = 1 kHz, RL = 8 Ω ICC ISTBY Parameter Min. 1.5 1.95 0.9 1.1 Total harmonic distortion + noise Pout = 600 mWRMS, G = 6 dB, 20 Hz < f < 20 kHz THD + N RL = 8 Ω + 15 µH, BW < 30 kHz Pout = 700 mWRMS, G = 6 dB, f = 1 kHz RL = 8 Ω + 15 µH, BW < 30 kHz 0.35 Efficiency Pout = 1.45 WRMS, RL = 4 Ω + ≥ 15 µH Pout = 0.9 WRMS, RL = 8 Ω+ ≥ 15 µH 78 88 PSRR Power supply rejection ratio with inputs grounded (3) f = 217 Hz, RL = 8 Ω, G = 6 dB, Vripple = 200 mVpp 63 CMRR Common mode rejection ratio f = 217 Hz, RL = 8 Ω, G = 6 dB, ΔVic = 200 mVpp Efficiency Gain Gain value (Rin in kΩ) W 2 % % dB 57 dB 273k Ω ----------------R in 300k Ω ----------------R in 327k Ω ----------------R in V/V RSTBY Internal resistance from standby to GND 273 300 327 kΩ FPWM Pulse width modulator base frequency 200 280 360 kHz SNR Signal to noise ratio (A-weighting) Pout = 0.8 W, RL = 8 Ω 85 tWU Wake-up time 5 10 ms tSTBY Standby time 5 10 ms Doc ID 10968 Rev 8 dB 9/44 Electrical characteristics Table 7. TS4962 Electrical characteristics at VCC = +4.2 V with GND = 0 V, Vicm = 2.1 V and Tamb = 25°C (unless otherwise specified)(1) (continued) Symbol Parameter VN Output voltage noise f = 20 Hz to 20 kHz, G = 6 dB Min. Typ. Unweighted RL = 4 Ω A-weighted RL = 4 Ω 85 60 Unweighted RL = 8 Ω A-weighted RL = 8 Ω 86 62 Unweighted RL = 4 Ω + 15 µH A-weighted RL = 4 Ω + 15 µH 83 60 Unweighted RL = 4 Ω + 30 µH A-weighted RL = 4 Ω + 30 µH 88 64 Unweighted RL = 8 Ω + 30 µH A-weighted RL = 8 Ω + 30 µH 78 57 Unweighted RL = 4 Ω + filter A-weighted RL = 4 Ω + filter Unweighted RL = 4 Ω + filter A-weighted RL = 4 Ω + filter 87 65 82 59 Max. Unit μVRMS 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 at f = 217 Hz. 10/44 Doc ID 10968 Rev 8 TS4962 Electrical characteristics Table 8. Electrical characteristics at VCC = +3.6 V with GND = 0 V, Vicm = 1.8 V, Tamb = 25°C (unless otherwise specified)(1) Symbol Typ. Max. Unit Supply current No input signal, no load 2 2.8 mA Standby current (2) No input signal, VSTBY = GND 10 1000 nA Voo Output offset voltage No input signal, RL = 8 Ω 3 25 mV Pout Output power, G = 6 dB THD = 1% max, f = 1 kHz, RL = 4 Ω THD = 10% max, f = 1 kHz, RL = 4 Ω THD = 1% max, f = 1 kHz, RL = 8 Ω THD = 10% max, f = 1 kHz, RL = 8 Ω ICC ISTBY Parameter Min. 1.1 1.4 0.7 0.85 Total harmonic distortion + noise Pout = 450 mWRMS, G = 6 dB, 20 Hz < f < 20 kHz THD + N RL = 8 Ω + 15 µH, BW < 30 kHz Pout = 500 mWRMS, G = 6 dB, f = 1 kHz RL = 8 Ω + 15 µH, BW < 30 kHz Efficiency W 2 % 0.1 Efficiency Pout = 1 WRMS, RL = 4 Ω + ≥ 15 µH Pout = 0.65 WRMS, RL = 8 Ω+ ≥ 15 µH 78 88 % PSRR Power supply rejection ratio with inputs grounded (3) f = 217 Hz, RL = 8 Ω, G = 6 dB, Vripple = 200 mVpp 62 dB CMRR Common mode rejection ratio f = 217 Hz, RL = 8 Ω, G = 6 dB, ΔVic = 200 mVpp 56 dB Gain Gain value (Rin in kΩ) 273k Ω ----------------R in 300k Ω ----------------R in 327k Ω ----------------R in V/V RSTBY Internal resistance from standby to GND 273 300 327 kΩ FPWM Pulse width modulator base frequency 200 280 360 kHz SNR Signal to noise ratio (A-weighting) Pout = 0.6 W, RL = 8 Ω 83 tWU Wake-up time 5 10 ms tSTBY Standby time 5 10 ms Doc ID 10968 Rev 8 dB 11/44 Electrical characteristics Table 8. Symbol VN TS4962 Electrical characteristics at VCC = +3.6 V with GND = 0 V, Vicm = 1.8 V, Tamb = 25°C (unless otherwise specified)(1) (continued) Parameter Min. Typ. Max. Unit Output voltage noise f = 20 Hz to 20 kHz, G = 6 dB Unweighted RL = 4 Ω A-weighted RL = 4 Ω 83 57 Unweighted RL = 8 Ω A-weighted RL = 8 Ω 83 61 Unweighted RL = 4 Ω + 15 µH A-weighted RL = 4 Ω + 15 µH 81 58 Unweighted RL = 4 Ω + 30 µH A-weighted RL = 4 Ω + 30 µH 87 62 Unweighted RL = 8 Ω + 30 µH A-weighted RL = 8 Ω + 30 µH 77 56 Unweighted RL = 4 Ω + filter A-weighted RL = 4 Ω + filter Unweighted RL = 4 Ω + filter A-weighted RL = 4 Ω + filter 85 63 80 57 μVRMS 1. All electrical values are guaranteed with correlation measurements at 2.5 V and 5 V. 2. Standby mode is activated when VSTBY is tied to GND. 3. Dynamic measurements - 20*log(rms(Vout)/rms(Vripple)). Vripple is the superimposed sinusoidal signal to VCC at f = 217 Hz. 12/44 Doc ID 10968 Rev 8 TS4962 Electrical characteristics Table 9. Electrical characteristics at VCC = +3.0 V with GND = 0 V, Vicm = 1.5 V, Tamb = 25°C (unless otherwise specified)(1) Symbol Typ. Max. Unit Supply current No input signal, no load 1.9 2.7 mA Standby current (2) No input signal, VSTBY = GND 10 1000 nA Voo Output offset voltage No input signal, RL = 8 Ω 3 25 mV Pout Output power, G = 6 dB THD = 1% max, f = 1 kHz, RL = 4 Ω THD = 10% max, f = 1 kHz, RL = 4 Ω THD = 1% max, f = 1 kHz, RL = 8 Ω THD = 10% max, f = 1 kHz, RL = 8 Ω ICC ISTBY Parameter Min. 0.7 1 0.5 0.6 Total harmonic distortion + noise Pout = 300 mWRMS, G = 6 dB, 20 Hz < f < 20 kHz THD + N RL = 8 Ω + 15 µH, BW < 30 kHz Pout = 350 mWRMS, G = 6 dB, f = 1 kHz RL = 8 Ω + 15 µH, BW < 30 kHz 0.1 Efficiency Efficiency Pout = 0.7 WRMS, RL = 4 Ω + ≥ 15 µH Pout = 0.45 WRMS, RL = 8 Ω+ ≥ 15 µH 78 88 PSRR Power supply rejection ratio with inputs grounded (3) f = 217 Hz, RL = 8 Ω, G = 6 dB, Vripple = 200 mVpp CMRR Common mode rejection ratio f = 217 Hz, RL = 8 Ω, G = 6 dB, ΔVic = 200 mVpp Gain Gain value (Rin in kΩ) W 2 % % dB 60 54 dB 273k Ω ----------------R in 300k Ω ----------------R in 327k Ω ----------------R in V/V RSTBY Internal resistance from standby to GND 273 300 327 kΩ FPWM Pulse width modulator base frequency 200 280 360 kHz SNR Signal to noise ratio (A-weighting) Pout = 0.4 W, RL = 8 Ω 82 tWU Wake-up time 5 10 ms tSTBY Standby time 5 10 ms Doc ID 10968 Rev 8 dB 13/44 Electrical characteristics Table 9. Symbol VN TS4962 Electrical characteristics at VCC = +3.0 V with GND = 0 V, Vicm = 1.5 V, Tamb = 25°C (unless otherwise specified)(1) (continued) Parameter Min. Typ. Max. Unit Output voltage noise f = 20 Hz to 20 kHz, G = 6 dB Unweighted RL = 4 Ω A-weighted RL = 4 Ω 83 57 Unweighted RL = 8 Ω A-weighted RL = 8 Ω 83 61 Unweighted RL = 4 Ω + 15 µH A-weighted RL = 4 Ω + 15 µH 81 58 Unweighted RL = 4 Ω + 30 µH A-weighted RL = 4 Ω + 30 µH 87 62 Unweighted RL = 8 Ω + 30 µH A-weighted RL = 8 Ω + 30 µH 77 56 Unweighted RL = 4 Ω + filter A-weighted RL = 4 Ω + filter Unweighted RL = 4 Ω + filter A-weighted RL = 4 Ω + filter 85 63 80 57 μVRMS 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 at f = 217 Hz. 14/44 Doc ID 10968 Rev 8 TS4962 Electrical characteristics Table 10. Electrical characteristics at VCC = +2.5 V with GND = 0 V, Vicm = 1.25V, Tamb = 25°C (unless otherwise specified) Symbol Typ. Max. Unit Supply current No input signal, no load 1.7 2.4 mA Standby current (1) No input signal, VSTBY = GND 10 1000 nA Voo Output offset voltage No input signal, RL = 8 Ω 3 25 mV Pout Output power, G = 6 dB THD = 1% max, f = 1 kHz, RL = 4 Ω THD = 10% max, f = 1 kHz, RL = 4 Ω THD = 1% max, f = 1 kHz, RL = 8 Ω THD = 10% max, f = 1 kHz, RL = 8 Ω ICC ISTBY Parameter Min. 0.5 0.65 0.33 0.41 W Total harmonic distortion + noise Pout = 180 mWRMS, G = 6 dB, 20 Hz < f < 20 kHz THD + N RL = 8 Ω + 15 µH, BW < 30 kHz Pout = 200 mWRMS, G = 6 dB, f = 1 kHz RL = 8 Ω + 15 µH, BW < 30 kHz 0.05 Efficiency Pout = 0.47 WRMS, RL = 4 Ω + ≥ 15 µH Pout = 0.3 WRMS, RL = 8 Ω+ ≥ 15 µH 78 88 % Efficiency 1 % PSRR Power supply rejection ratio with inputs grounded (2) f = 217 Hz, RL = 8 Ω, G = 6 dB, Vripple = 200 mVpp 60 dB CMRR Common mode rejection ratio f = 217 Hz, RL = 8 Ω, G = 6 dB, ΔVic = 200 mVpp 54 dB Gain Gain value (Rin in kΩ) 273k Ω ----------------R in 300k Ω ----------------R in 327k Ω ----------------R in V/V RSTBY Internal resistance from standby to GND 273 300 327 kΩ FPWM Pulse width modulator base frequency 200 280 360 kHz SNR Signal to noise ratio (A-weighting) Pout = 0.3 W, RL = 8 Ω 80 tWU Wake-up time 5 10 ms tSTBY Standby time 5 10 ms Doc ID 10968 Rev 8 dB 15/44 Electrical characteristics Table 10. Symbol VN TS4962 Electrical characteristics at VCC = +2.5 V with GND = 0 V, Vicm = 1.25V, Tamb = 25°C (unless otherwise specified) (continued) Parameter Min. Typ. Max. Unit Output voltage noise f = 20 Hz to 20 kHz, G = 6 dB Unweighted RL = 4 Ω A-weighted RL = 4 Ω 85 60 Unweighted RL = 8 Ω A-weighted RL = 8 Ω 86 62 Unweighted RL = 4 Ω + 15 µH A-weighted RL = 4 Ω + 15 µH 76 56 Unweighted RL = 4 Ω + 30 µH A-weighted RL = 4 Ω + 30 µH 82 60 Unweighted RL = 8 Ω + 30 µH A-weighted RL = 8 Ω + 30 µH 67 53 Unweighted RL = 4 Ω + filter A-weighted RL = 4 Ω + filter Unweighted RL = 4 Ω + filter A-weighted RL = 4 Ω + filter 78 57 74 54 μVRMS 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 at f = 217 Hz. 16/44 Doc ID 10968 Rev 8 TS4962 Electrical characteristics Table 11. Electrical characteristics at VCC +2.4 V with GND = 0 V, Vicm = 1.2 V, Tamb = 25°C (unless otherwise specified) Symbol Parameter Min. Typ. Max. Unit Supply current No input signal, no load 1.7 mA Standby current (1) No input signal, VSTBY = GND 10 nA Voo Output offset voltage No input signal, RL = 8 Ω 3 mV Pout Output power, G = 6 dB THD = 1% max, f = 1 kHz, RL = 4 Ω THD = 10% max, f = 1 kHz, RL = 4 Ω THD = 1% max, f = 1 kHz, RL = 8 Ω THD = 10% max, f = 1 kHz, RL = 8 Ω ICC ISTBY THD + N Total harmonic distortion + noise Pout = 150 mWRMS, G = 6 dB, 20 Hz < f < 20 kHz RL = 8 Ω + 15 µH, BW < 30 kHz Efficiency Efficiency Pout = 0.38 WRMS, RL = 4 Ω + ≥ 15 µH Pout = 0.25 WRMS, RL = 8 Ω+ ≥ 15 µH CMRR Gain 0.42 0.61 0.3 0.38 Common mode rejection ratio f = 217 Hz, RL = 8 Ω, G = 6 dB, ΔVic = 200 mVpp Gain value (Rin in kΩ) W 1 % 77 86 % 54 dB 273k Ω ----------------R in 300k Ω ----------------R in 327k Ω ----------------R in V/V 273 300 327 kΩ RSTBY Internal resistance from standby to GND FPWM Pulse width modulator base frequency 280 kHz SNR Signal to noise ratio (A-weighting) Pout = 0.25 W, RL = 8 Ω 80 dB tWU Wake-up time 5 ms tSTBY Standby time 5 ms Doc ID 10968 Rev 8 17/44 Electrical characteristics Table 11. TS4962 Electrical characteristics at VCC +2.4 V with GND = 0 V, Vicm = 1.2 V, Tamb = 25°C (unless otherwise specified) (continued) Symbol Parameter VN Output voltage noise f = 20 Hz to 20 kHz, G = 6 dB Typ. Unweighted RL = 4 Ω A-weighted RL = 4 Ω 85 60 Unweighted RL = 8 Ω A-weighted RL = 8 Ω 86 62 Unweighted RL = 4 Ω + 15 µH A-weighted RL = 4 Ω + 15 µH 76 56 Unweighted RL = 4 Ω + 30 µH A-weighted RL = 4 Ω + 30 µH 82 60 Unweighted RL = 8 Ω + 30 µH A-weighted RL = 8 Ω + 30 µH 67 53 Unweighted RL = 4 Ω + filter A-weighted RL = 4 Ω + filter Unweighted RL = 4 Ω + filter A-weighted RL = 4 Ω + filter 78 57 74 54 1. Standby mode is active when VSTBY is tied to GND. 18/44 Min. Doc ID 10968 Rev 8 Max. Unit μVRMS TS4962 3.1 Electrical characteristics Electrical characteristics curves The graphs shown in this section use the following abbreviations. ● RL + 15 μH or 30 μH = pure resistor + very low series resistance inductor ● Filter = LC output filter (1 µF + 30 µH for 4 Ω and 0. 5µF + 60 µH for 8 Ω) All measurements are done with CS1 = 1 µF and CS2 = 100 nF (see Figure 2), except for the PSRR where CS1 is removed (see Figure 3). Figure 2. Schematic used for test measurements Vcc 1uF 100nF Cs2 Cs1 + Cin GND GND Rin Out+ In+ TS4962 Cin Rin 4 or 8 Ohms 15uH or 30uH 150k 5th order or RL filter LC Filter In- 50kHz low pass Out- 150k GND Audio Measurement Bandwidth < 30kHz Figure 3. Schematic used for PSSR 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 In- 50kHz low pass filter Out- 150k GND GND 5th order 50kHz low pass Reference RMS Selective Measurement Bandwidth=1% of Fmeas filter Doc ID 10968 Rev 8 19/44 Electrical characteristics TS4962 Current consumption vs. power supply voltage Figure 4. Figure 5. 2.5 2.5 Current Consumption (mA) Current Consumption (mA) No load Tamb=25°C 2.0 1.5 1.0 0.5 0.0 2.0 1.5 1.0 0.5 0.0 0 Current consumption vs. standby voltage 1 2 3 4 5 Vcc = 5V No load Tamb=25°C 0 1 2 Figure 6. Current consumption vs. standby voltage 4 5 Output offset voltage vs. common mode input voltage Figure 7. 2.0 10 G = 6dB Tamb = 25°C 8 1.5 Voo (mV) Current Consumption (mA) 3 Standby Voltage (V) Power Supply Voltage (V) 1.0 0.5 0.0 0.0 1.0 1.5 2.0 2.5 Vcc=5V Vcc=3.6V 4 2 Vcc = 3V No load Tamb=25°C 0.5 6 Vcc=2.5V 0 0.0 3.0 0.5 1.0 Figure 8. 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Common Mode Input Voltage (V) Standby Voltage (V) Efficiency vs. output power Efficiency vs. output power Figure 9. 100 200 100 600 400 60 300 40 Power Dissipation 20 0 0.0 20/44 0.5 200 Vcc=5V RL=4Ω + ≥ 15μH F=1kHz THD+N≤1% 1.0 1.5 Output Power (W) 2.0 100 0 2.2 80 150 Efficiency (%) 500 60 100 40 Power Dissipation Vcc=3V RL=4Ω + ≥ 15μH F=1kHz THD+N≤1% 20 0 0.0 Doc ID 10968 Rev 8 0.1 0.2 0.3 0.4 Output Power (W) 0.5 0.6 50 0 0.7 Power Dissipation (mW) Efficiency Efficiency Power Dissipation (mW) Efficiency (%) 80 TS4962 Electrical characteristics Figure 10. Efficiency vs. output power Figure 11. Efficiency vs. output power 75 100 100 100 60 40 Power Dissipation 50 Vcc=5V RL=8Ω + ≥ 15μH F=1kHz THD+N≤1% 20 0 0.0 0.2 0.4 0.6 0.8 Output Power (W) 1.0 80 Efficiency 0.2 0.3 Output Power (W) 0 0.5 0.4 RL = 8Ω + ≥ 15μH F = 1kHz BW < 30kHz Tamb = 25°C THD+N=10% Output power (W) Output power (W) 2.0 RL = 4Ω + ≥ 15μH F = 1kHz BW < 30kHz Tamb = 25°C 0.1 25 Vcc=3V RL=8Ω + ≥ 15μH F=1kHz THD+N≤1% Figure 13. Output power vs. power supply voltage 3.5 2.5 Power Dissipation 0 0.0 Figure 12. Output power vs. power supply voltage 3.0 40 20 0 1.4 1.2 50 60 Power Dissipation (mW) Efficiency (%) Efficiency Efficiency (%) 80 Power Dissipation (mW) 150 2.0 1.5 THD+N=1% 1.0 1.5 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 5.5 Figure 14. PSRR vs. frequency 3.5 4.0 Vcc (V) 4.5 5.0 5.5 0 Vripple = 200mVpp Inputs = Grounded G = 6dB, Cin = 4.7μF RL = 4Ω + 15μH ΔR/R≤0.1% Tamb = 25°C -20 -30 -20 -40 Vcc=5V, 3.6V, 2.5V -50 -30 -40 Vcc=5V, 3.6V, 2.5V -50 -60 -60 -70 -70 20 100 Vripple = 200mVpp Inputs = Grounded G = 6dB, Cin = 4.7μF RL = 4Ω + 30μH ΔR/R≤0.1% Tamb = 25°C -10 PSRR (dB) -10 PSRR (dB) 3.0 Figure 15. PSRR vs. frequency 0 -80 2.5 1000 Frequency (Hz) 10000 20k -80 20 Doc ID 10968 Rev 8 100 1000 Frequency (Hz) 10000 20k 21/44 Electrical characteristics TS4962 Figure 16. PSRR vs. frequency Figure 17. PSRR vs. frequency 0 0 Vripple = 200mVpp Inputs = Grounded G = 6dB, Cin = 4.7μF RL = 4Ω + Filter ΔR/R≤0.1% Tamb = 25°C PSRR (dB) -20 -30 -20 -40 Vcc=5V, 3.6V, 2.5V -50 -40 Vcc=5V, 3.6V, 2.5V -50 -60 -70 -70 20 100 1000 Frequency (Hz) -80 10000 20k Figure 18. PSRR vs. frequency 100 1000 Frequency (Hz) 10000 20k 0 Vripple = 200mVpp Inputs = Grounded G = 6dB, Cin = 4.7μF RL = 8Ω + 30μH ΔR/R≤0.1% Tamb = 25°C -20 -30 -20 -40 Vcc=5V, 3.6V, 2.5V -50 -30 -40 Vcc=5V, 3.6V, 2.5V -50 -60 -60 -70 -70 20 100 Vripple = 200mVpp Inputs = Grounded G = 6dB, Cin = 4.7μF RL = 8Ω + Filter ΔR/R≤0.1% Tamb = 25°C -10 PSRR (dB) -10 -80 20 Figure 19. PSRR vs. frequency 0 PSRR (dB) -30 -60 -80 Vripple = 200mVpp Inputs = Grounded G = 6dB, Cin = 4.7μF RL = 8Ω + 15μH ΔR/R≤0.1% Tamb = 25°C -10 PSRR (dB) -10 1000 Frequency (Hz) -80 10000 20k 20 100 1000 Frequency (Hz) 10000 20k Figure 20. PSRR vs. common mode input voltage Figure 21. CMRR vs. frequency 0 -10 RL=4Ω + 15μH G=6dB ΔVicm=200mVpp ΔR/R≤0.1% Cin=4.7μF Tamb = 25°C Vcc=2.5V -20 -30 CMRR (dB) PSRR(dB) -20 0 Vripple = 200mVpp F = 217Hz, G = 6dB RL ≥ 4Ω + ≥ 15μH Tamb = 25°C Vcc=3.6V -40 -50 Vcc=5V, 3.6V, 2.5V -40 -60 -60 -70 -80 0.0 Vcc=5V 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) 22/44 Doc ID 10968 Rev 8 100 1000 Frequency (Hz) 10000 20k TS4962 Electrical characteristics Figure 22. CMRR vs. frequency Figure 23. CMRR vs. frequency 0 0 CMRR (dB) -20 -20 Vcc=5V, 3.6V, 2.5V -40 -60 100 20 1000 Frequency (Hz) 10000 20k Figure 24. CMRR vs. frequency 10000 20k 0 RL=8Ω + 15μH G=6dB ΔVicm=200mVpp ΔR/R≤0.1% Cin=4.7μF Tamb = 25°C RL=8Ω + 30μH G=6dB ΔVicm=200mVpp ΔR/R≤0.1% Cin=4.7μF Tamb = 25°C -20 Vcc=5V, 3.6V, 2.5V -40 -60 Vcc=5V, 3.6V, 2.5V -40 -60 20 100 1000 Frequency (Hz) 10000 20k Figure 26. CMRR vs. frequency 100 20 1000 Frequency (Hz) 10000 20k Figure 27. CMRR vs. common mode input voltage -20 0 RL=8Ω + Filter G=6dB ΔVicm=200mVpp ΔR/R≤0.1% Cin=4.7μF Tamb = 25°C -30 CMRR(dB) -20 1000 Frequency (Hz) Figure 25. CMRR vs. frequency CMRR (dB) -20 100 20 0 CMRR (dB) Vcc=5V, 3.6V, 2.5V -40 -60 CMRR (dB) RL=4Ω + Filter G=6dB ΔVicm=200mVpp ΔR/R≤0.1% Cin=4.7μF Tamb = 25°C CMRR (dB) RL=4Ω + 30μH G=6dB ΔVicm=200mVpp ΔR/R≤0.1% Cin=4.7μF Tamb = 25°C Vcc=5V, 3.6V, 2.5V -40 -40 ΔVicm = 200mVpp F = 217Hz G = 6dB RL ≥ 4Ω + ≥ 15μH Tamb = 25°C Vcc=2.5V -50 Vcc=3.6V -60 -60 Vcc=5V 20 100 1000 Frequency (Hz) 10000 20k -70 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Common Mode Input Voltage (V) Doc ID 10968 Rev 8 23/44 Electrical characteristics TS4962 Figure 28. THD+N vs. output power Figure 29. THD+N vs. output power 10 Vcc=2.5V 0.1 1 0.01 0.1 Output Power (W) 1 3 Figure 30. THD+N vs. output power 0.01 1E-3 Vcc=5V Vcc=3.6V Vcc=2.5V 1 THD + N (%) THD + N (%) 0.01 0.1 Output Power (W) 1 3 RL = 8Ω + 30μH or Filter F = 100Hz G = 6dB BW < 30kHz Tamb = 25°C Vcc=5V Vcc=3.6V Vcc=2.5V 0.1 0.01 1E-3 0.01 0.1 Output Power (W) 1 2 Figure 32. THD+N vs. output power 0.01 1E-3 0.01 0.1 Output Power (W) 1 2 Figure 33. THD+N vs. output power 10 10 RL = 4Ω + 15μH F = 1kHz G = 6dB BW < 30kHz Tamb = 25°C Vcc=5V Vcc=3.6V THD + N (%) THD + N (%) Vcc=2.5V 10 RL = 8Ω + 15μH F = 100Hz G = 6dB BW < 30kHz Tamb = 25°C 0.1 Vcc=2.5V 0.1 1E-3 24/44 Vcc=3.6V Figure 31. THD+N vs. output power 10 1 Vcc=5V 0.1 0.01 1E-3 1 RL = 4Ω + 30μH or Filter F = 100Hz G = 6dB BW < 30kHz Tamb = 25°C Vcc=3.6V THD + N (%) THD + N (%) 1 10 Vcc=5V RL = 4Ω + 15μH F = 100Hz G = 6dB BW < 30kHz Tamb = 25°C 1 RL = 4Ω + 30μH or Filter F = 1kHz G = 6dB BW < 30kHz Tamb = 25°C Vcc=5V Vcc=3.6V Vcc=2.5V 0.1 0.01 0.1 Output Power (W) 1 3 1E-3 Doc ID 10968 Rev 8 0.01 0.1 Output Power (W) 1 3 TS4962 Electrical characteristics Figure 34. THD+N vs. output power Figure 35. THD+N vs. output power 1 10 RL = 8Ω + 15μH F = 1kHz G = 6dB BW < 30kHz Tamb = 25°C Vcc=3.6V Vcc=2.5V 1E-3 0.01 0.1 Output Power (W) 1 1E-3 2 Figure 36. THD+N vs. frequency 0.01 0.1 Output Power (W) 1 THD + N (%) Po=1.4W RL=4Ω + 30μH or Filter G=6dB Bw < 30kHz Vcc=5V Tamb = 25°C 50 100 1000 Frequency (Hz) 10000 20k 0.01 Po=1.4W 100 50 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 RL=4Ω + 30μH or Filter G=6dB Bw < 30kHz Vcc=3.6V Tamb = 25°C 1 Po=0.85W THD + N (%) THD + N (%) 2 Po=0.7W Figure 38. THD+N vs. frequency 0.1 Po=0.85W 0.1 Po=0.42W 0.01 1 0.1 Po=0.7W 1 Vcc=2.5V 10 RL=4Ω + 15μH G=6dB Bw < 30kHz Vcc=5V Tamb = 25°C 0.1 0.01 Vcc=3.6V Figure 37. THD+N vs. frequency 10 THD + N (%) 1 Vcc=5V 0.1 0.1 1 RL = 8Ω + 30μH or Filter F = 1kHz G = 6dB BW < 30kHz Tamb = 25°C Vcc=5V THD + N (%) THD + N (%) 10 50 100 1000 Frequency (Hz) Po=0.42W 10000 20k 0.01 50 Doc ID 10968 Rev 8 100 1000 Frequency (Hz) 10000 20k 25/44 Electrical characteristics TS4962 Figure 40. THD+N vs. frequency Figure 41. THD+N vs. frequency 10 1 Po=0.35W THD + N (%) THD + N (%) 1 10 RL=4Ω + 15μH G=6dB Bw < 30kHz Vcc=2.5V Tamb = 25°C 0.1 RL=4Ω + 30μH or Filter G=6dB Bw < 30kHz Vcc=2.5V Tamb = 25°C Po=0.35W 0.1 Po=0.17W 0.01 50 100 1000 Frequency (Hz) Po=0.17W 10000 20k Figure 42. THD+N vs. frequency 0.01 1000 Frequency (Hz) Po=0.85W 1 0.1 RL=8Ω + 30μH or Filter G=6dB Bw < 30kHz Vcc=5V Tamb = 25°C 50 100 1000 Frequency (Hz) Po=0.42W 10000 20k Figure 44. THD+N vs. frequency 0.01 100 1000 Frequency (Hz) RL=8Ω + 30μH or Filter G=6dB Bw < 30kHz Vcc=3.6V Tamb = 25°C Po=0.45W 1 0.1 Po=0.45W 0.1 Po=0.22W 0.01 26/44 10000 20k 10 RL=8Ω + 15μH G=6dB Bw < 30kHz Vcc=3.6V Tamb = 25°C THD + N (%) THD + N (%) 50 Figure 45. THD+N vs. frequency 10 1 Po=0.85W 0.1 Po=0.42W 0.01 10000 20k 10 RL=8Ω + 15μH G=6dB Bw < 30kHz Vcc=5V Tamb = 25°C THD + N (%) THD + N (%) 100 Figure 43. THD+N vs. frequency 10 1 50 50 100 1000 Frequency (Hz) Po=0.22W 10000 20k 0.01 50 Doc ID 10968 Rev 8 100 1000 Frequency (Hz) 10000 20k TS4962 Electrical characteristics Figure 46. THD+N vs. frequency Figure 47. THD+N vs. frequency 10 10 RL=8Ω + 15μH G=6dB Bw < 30kHz Vcc=2.5V Tamb = 25°C 1 Po=0.18W THD + N (%) THD + N (%) 1 Po=0.1W 0.1 0.01 50 100 1000 Frequency (Hz) 10000 20k 0.01 6 6 Vcc=5V, 3.6V, 2.5V RL=4Ω + 15μH G=6dB Vin=500mVpp Cin=1μF Tamb = 25°C 20 100 10000 20k Figure 50. Gain vs. frequency 20 6 Differential Gain (dB) 6 0 Vcc=5V, 3.6V, 2.5V RL=4Ω + Filter G=6dB Vin=500mVpp Cin=1μF Tamb = 25°C 100 1000 Frequency (Hz) 1000 Frequency (Hz) 10000 20k Vcc=5V, 3.6V, 2.5V 4 10000 20k RL=8Ω + 15μH G=6dB Vin=500mVpp Cin=1μF Tamb = 25°C 2 0 20 100 Figure 51. Gain vs. frequency 8 2 10000 20k RL=4Ω + 30μH G=6dB Vin=500mVpp Cin=1μF Tamb = 25°C 2 8 4 1000 Frequency (Hz) Vcc=5V, 3.6V, 2.5V 4 0 1000 Frequency (Hz) 100 50 Figure 49. Gain vs. frequency 8 0 Differential Gain (dB) Po=0.1W 8 2 Po=0.18W 0.1 Differential Gain (dB) Differential Gain (dB) Figure 48. Gain vs. frequency 4 RL=8Ω + 30μH or Filter G=6dB Bw < 30kHz Vcc=2.5V Tamb = 25°C 20 Doc ID 10968 Rev 8 100 1000 Frequency (Hz) 10000 20k 27/44 Electrical characteristics TS4962 Figure 53. Gain vs. frequency 8 8 6 6 Differential Gain (dB) Differential Gain (dB) Figure 52. Gain vs. frequency Vcc=5V, 3.6V, 2.5V 4 RL=8Ω + 30μH G=6dB Vin=500mVpp Cin=1μF Tamb = 25°C 2 0 Vcc=5V, 3.6V, 2.5V 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 and shutdown times VCC = 5V, G = 6dB, Cin= 1µF (5ms/div) 8 Differential Gain (dB) Vo1 6 Vo2 Vcc=5V, 3.6V, 2.5V 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 57. Startup and shutdown times Figure 56. Startup and shutdown times VCC = 5V, G = 6dB, Cin= 100nF (5ms/div) VCC = 3V, G = 6dB, Cin= 1µF (5ms/div) Vo1 Vo1 Vo2 Vo2 Standby Standby Vo1-Vo2 28/44 Vo1-Vo2 Doc ID 10968 Rev 8 TS4962 Electrical characteristics Figure 59. Startup and shutdown times Figure 58. Startup and shutdown times VCC = 5V, G = 6dB, No Cin (5ms/div) VCC = 3V, G = 6dB, Cin= 100nF (5ms/div) Vo1 Vo1 Vo2 Vo2 Standby Standby Vo1-Vo2 Vo1-Vo2 Figure 60. Startup and shutdown times VCC = 3V, G = 6dB, No Cin (5ms/div) Vo1 Vo2 Standby Vo1-Vo2 Doc ID 10968 Rev 8 29/44 Application information TS4962 4 Application information 4.1 Differential configuration principle The TS4962 is a monolithic, fully differential input/output class D power amplifier. The TS4962 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 fully 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 because of common-mode feedback loop. The main disadvantage is that, since the differential function is directly linked to the external resistor mismatching, particular attention should be paid to this mismatching in order to obtain the best performance from the amplifier. 4.2 Gain in typical application schematic Typical differential applications are shown in Figure 1 on page 6. 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 kΩ. Due to the tolerance of the internal 150 kΩ feedback resistor, the differential gain is in the range (no tolerance on Rin): 273327 --------≤ A V ≤ ---------diff R in R in 30/44 Doc ID 10968 Rev 8 TS4962 4.3 Application information 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 a Vicm limitation in the input stage (see Table 3: Operating conditions on page 4), the common-mode feedback loop can play 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 × 150kΩ V icm = -----------------------------------------------------------------------------2 × ( R in + 150kΩ) (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 150 kΩ resistor, it is also important to check Vicm in these conditions. V CC × R in + 2 × V IC × 163.5kΩ V CC × R in + 2 × V IC × 136.5kΩ ---------------------------------------------------------------------------------- ≤ V icm ≤ ---------------------------------------------------------------------------------2 × ( R in + 136.5kΩ) 2 × ( R in + 163.5kΩ) If the result of the Vicm calculation is not in the previous range, input coupling capacitors must be used. With VCC between 2.4 and 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, which is lower than 3 V-0.8 V = 2.2 V. With 136.5 kΩ we find 1.97 V and with 163.5 kΩ we have 2.02 V. Therefore, no input coupling capacitors are required. 4.4 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 -3 dB cut-off frequency. 1 F CL = -------------------------------------2π × R in × C in (Hz) So, for a desired cut-off frequency we can calculate Cin, 1 C in = ---------------------------------------2π × R in × F CL (F) with Rin in Ω and FCL in Hz. Doc ID 10968 Rev 8 31/44 Application information 4.5 TS4962 Decoupling of the circuit A power supply capacitor, referred to as CS, is needed to correctly bypass the TS4962. The TS4962 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 TS4962 in order to avoid any extra parasitic inductance being created by 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 Ω 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). 4.6 Wake-up time (tWU) When the standby is released to set the device ON, there is a wait of about 5 ms. The TS4962 has an internal digital delay that mutes the outputs and releases them after this time in order to avoid any pop noise. 4.7 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 standby mode is about 5 ms. This time is used to decrease the gain and avoid any pop noise during the shutdown phase. 4.8 Consumption in standby mode Between the standby pin and GND there is an internal 300 kΩ resistor. This resistor forces the TS4962 to be in standby mode when the standby input pin is left floating. However, this resistor also introduces additional power consumption if the standby pin voltage is not 0 V. For example, with a 0.4 V standby voltage pin, Table 3 on page 4 shows that you must add 0.4 V/300 kΩ = 1.3 µA typical (0.4 V/273 kΩ = 1.46 µA maximum) to the standby current specified in Table 5 on page 5. 32/44 Doc ID 10968 Rev 8 TS4962 Single-ended input configuration It is possible to use the TS4962 in a single-ended input configuration. However, input coupling capacitors are needed in this configuration. Figure 61 shows a typical single-ended input application. Figure 61. Single-ended input typical application Vcc 6 Cs 1u Vcc Ve 1 Stdby Cin 300k Standby Rin GND 4 Internal Bias 5 Output - 3 GND Out+ 150k InIn+ + H PWM Bridge SPEAKER Rin 8 150k Cin Out- Oscillator GND GND 7 GND All formulas are identical except for the gain with Rin in kΩ. AV sin gle Ve 300= ------------------------------ = --------+ R in Out – Out 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 TS4962 inputs (In- and In+) be equal. Figure 62. Typical application schematic with multiple single-ended inputs Vcc Vek Standby Cink 6 Rink 1 Stdby GND Ve1 Cin1 Rin1 4 3 GND Ceq GND Cs 1u Vcc 300k 4.9 Application information Internal Bias GND Out+ 150k 5 Output - InIn+ + PWM H Bridge SPEAKER Req 8 150k Out- Oscillator GND 7 GND Doc ID 10968 Rev 8 33/44 Application information TS4962 We have the following equations. + 300 300 Out – Out = V e1 × ------------- + …+ V ek × ------------R ink R in1 (V) k C eq = C in i Σ j=1 C in i 1 = ------------------------------------------------------- (F) 2× π× R × F ini CL i 1 R eq = -----------------k 1 ∑ --------Rini j =1 In general, for mixed situations (single-ended and differential inputs) it is best to use the same rule, that is, equalize impedance on both TS4962 inputs. 4.10 Output filter considerations The TS4962 is designed to operate without an output filter. However, due to very sharp transients on the TS4962 output, EMI-radiated emissions may cause some standard compliance issues. These EMI standard compliance issues can appear if the distance between the TS4962 outputs and the 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 TS4962 output pins and the speaker terminals. ● Use ground planes for "shielding" sensitive wires. ● Place, as close as possible to the TS4962 and in series with each output, a ferrite bead with a rated current of at least 2.5 A and an impedance greater than 50 Ω at frequencies above 30 MHz. If, after testing, these ferrite beads are not necessary, replace them by a short-circuit. ● Allow enough footprint to place, if necessary, a capacitor to short perturbations to ground (see Figure 63). Figure 63. Method for shorting perturbations to ground Ferrite chip bead To speaker From TS4962 output about 100pF Gnd 34/44 Doc ID 10968 Rev 8 TS4962 Application information In the case where the distance between the TS4962 output and the speaker terminals is high, it is possible to observe 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 represented in Figure 1 on page 6). It should be placed as close as possible to the device. 4.11 Several examples with summed inputs 4.11.1 Example 1: dual differential inputs Figure 64. Typical application schematic with dual differential inputs Vcc 6 Standby Cs 1u Vcc 1 Stdby 300k R2 E2+ R1 4 E1+ E1- 3 Internal Bias GND Out+ 150k 5 Output - InIn+ + H PWM Bridge SPEAKER R1 8 150k E2R2 Out- Oscillator GND 7 GND With (Ri in kΩ): + - + - Out – Out- = 300 A V = --------------------------------------1 + R1 E1 – E1 300 Out – Out 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 and V IC = -----------------------V IC = -----------------------1 2 2 2 Doc ID 10968 Rev 8 35/44 Application information 4.11.2 TS4962 Example 2: one differential input plus one single-ended input Figure 65. Typical application schematic with one differential input and one single-ended input Vcc 6 Standby Cs 1u Vcc 1 Stdby 300k R2 E2+ C1 R1 E1+ E2- 4 3 Internal Bias Out+ 150k Output - InIn+ + H Bridge PWM SPEAKER R2 8 150k GND C1 R1 Out- Oscillator GND 7 GND With (Ri in kΩ) : + - + - Out – Out 300 A V = ------------------------------- = ---------1 + R1 E1 300 Out – Out A V = ------------------------------- = ---------2 + R2 E2 – E2 1 C 1 = -------------------------------------2π × R 1 × F CL 36/44 GND 5 Doc ID 10968 Rev 8 (F) TS4962 Demonstration board A demonstration board for the TS4962 is available. For more information about this demonstration board, refer to the application note AN2406 "TS4962IQ class D audio amplifier evaluation board user guidelines" available on www.st.com. Figure 66. Schematic diagram of mono class D demonstration board for the TS4962 DFN package Vcc Cn4 Vcc 1 2 3 Cn2 Cn6 C3 1uF Gnd 6 GND GND U1 Vcc 1 Stdby C1 100nF Cn1 1 2 3 Negative input Positive Input Input 300k 5 Demonstration board R1 4 InIn+ 150k GND R2 100nF C2 150k 3 Internal Bias Out+ 150k 5 Cn5 Output PWM + Positive Output H Negative Output Bridge Speaker 8 150k Out- Oscillator GND TS4962DFN 7 Cn3 GND Figure 67. Top view Doc ID 10968 Rev 8 37/44 Demonstration board TS4962 Figure 68. Bottom layer Figure 69. Top layer 38/44 Doc ID 10968 Rev 8 TS4962 6 Recommended footprint Recommended footprint Figure 70. Recommended footprint for TS4962 DFN package 1.8mm 0.8mm 0.35mm 2.2mm 0.65mm 1.4mm Doc ID 10968 Rev 8 39/44 Package information 7 TS4962 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. 40/44 Doc ID 10968 Rev 8 TS4962 Package information Figure 71. DFN8 3 x 3 exposed pad package mechanical drawing (pitch 0.65 mm) Table 12. DFN8 3 x 3 exposed pad package mechanical data (pitch 0.65 mm) Dimensions Ref. A Millimeters Min. Typ. Max. Min. Typ. Max. 0.50 0.60 0.65 0.020 0.024 0.026 0.02 0.05 0.0008 0.002 A1 A3 0.22 0.009 b 0.25 0.30 0.35 0.010 0.012 0.014 D 2.85 3.00 3.15 0.112 0.118 0.124 D2 1.60 1.70 1.80 0.063 0.067 0.071 E 2.85 3.00 3.15 0.112 0.118 0.124 E2 1.10 1.20 1.30 0.043 0.047 0.051 e L ddd Note: Inches 0.65 0.50 0.55 0.026 0.60 0.020 0.022 0.08 0.024 0.003 1 The pin 1 identifier must be visible on the top surface of the package by using an indentation mark or other feature of the package body. Exact shape and size of this feature are optional. 2 The dimension L does not conform with JEDEC MO-248, which recommends 0.40+/-0.10 mm. For enhanced thermal performance, the exposed pad must be soldered to a copper area on the PCB, acting as a heatsink. This copper area can be electrically connected to pin 7 or left floating. Doc ID 10968 Rev 8 41/44 Ordering information 8 TS4962 Ordering information Table 13. Order codes Part number TS4962IQT 42/44 Temperature range Package Packaging Marking -40°C, +85°C DFN8 Tape & reel K962 Doc ID 10968 Rev 8 TS4962 9 Revision history Revision history Table 14. Document revision history Date Revision Changes 31-May-2006 5 Modified package information. Now includes only standard DFN8 package. 16-Oct-2006 6 Added curves in Section 3: Electrical characteristics. Added evaluation board information in Section 5: Demonstration board. Added recommended footprint. 10-Jan-2007 7 Added paragraph about rated voltage of capacitor in Section 4.5: Decoupling of the circuit. 18-Jan-2010 8 Added Table 5: Pin description. 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