G1432 Global Mixed-mode Technology Inc. 2W Stereo Audio Amplifier Features General Description The G1432 is a stereo audio power amplifier in 24pin TSSOP thermal pad package or 24pin QFN package. It can drive 1.8W continuous RMS power into 4Ω load per channel in Bridge-Tied Load (BTL) mode at 5V supply voltage. Its THD is smaller than 1% under the above operation condition. The G1432 can mute the output when Mute is activated. For the low current consumption applications, the SHDN mode is supported to disable the G1432 when it is idle. The current consumption can be further reduced to below 5µA. Depop Circuitry Integrated Output Power at 1% THD+N, VDD=5V --1.8W/CH (typical) into a 4Ω Load --1.2W/CH (typical) into a 8Ω Load Maximum Output Power Clamping Circuitry Integrated Bridge-Tied Load (BTL) Stereo Input MUX Mute and Shutdown Control Available Surface-Mount Power Package 24-Pin TSSOP-P & 24-Pin QFN Available The G1432 also supports two input paths, that means two different gain loops can be set in the same PCB and choosing either one by setting IN1 /IN2 pin. It enhances the hardware designing flexibility. The G1432 also supports an extra function -- the maximum output power clamping function to protect the speakers from burned-out. Applications Stereo Power Amplifiers for Notebooks or Desktop Computers Multimedia Monitors Stereo Power Amplifiers for Portable Audio Systems Ordering Information TEMP. RANGE ORDER MARKING NUMBER PACKAGE (Pb free) G1432F3U G1432 -40°C to +85°C TSSOP-24 (FD) G1432Q5U G1432 -40°C to +85°C QFN4X4-24 Note: F3:TSSOP-24 (FD) Q5:QFN4X4-24 U: Tape & Reel RIN2 RBYPASS LVDD SHUTDOWN 7 18 RVDD 8 17 GND NC 9 16 IN1/IN2 LOUT- 10 NC 11 15 14 ROUTMUTE GND/HS 12 13 GND/HS Top View Thermal Pad RVDD GND IN1/IN2 15 14 13 21 10 GND/HS GND/HS 22 9 GND/HS NC 23 8 NC LOUT+ 24 7 LOUT- Bottom View TSSOP-24 (FD) Thermal Pad 6 19 MUTE GND/HS NC 20 6 11 5 5 12 20 4 LIN2 LBYPASS 19 VOL LVDD RIN1 ROUT+ SHUTDOWN 21 RIN2 4 RBYPBASS LIN1 16 ROUT+ 3 22 LBYPASS 3 RIN1 VOL LOUT+ GND/HS 2 23 1 24 2 LIN1 1 NC LIN2 GND/HS 17 G1432 18 Pin Configuration ROUT- G1432 QFN4X4-24 Note: Recommend connecting the Thermal Pad to the GND for excellent power dissipation. TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 1 G1432 Global Mixed-mode Technology Inc. Absolute Maximum Ratings Power Dissipation (1) TSSOP-24 (FD) TA ≤ 25°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.7W TA ≤ 70°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.7W TA ≤ 85°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.4W Electrostatic Discharge, VESD Human body mode . . . . . . . . . . . . . . .-3000 to 3000V(2) Supply Voltage, VDD . . . . . . . . . . . . . . . . . . . . . . . . .6V Input Voltage, VI . . . . . . . . . . . . . . . -0.3V to VDD+0.3V Operating Ambient Temperature Range TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40°C to +85°C Maximum Junction Temperature, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150°C Storage Temperature Range, TSTG . . . . . . . . . . . . . . . . . . . . . . . . . . .-65°C to+150°C Reflow Temperature (soldering, 10sec) . . . . . . 260°C Note: (1) : Recommended PCB Layout. (2) : Human body model : C = 100pF, R = 1500Ω, 3 positive pulses plus 3 negative pulses Electrical Characteristics DC Electrical Characteristics, TA=+25°C PARAMETER SYMBOL Supply Current in Mute Mode IDD(MUTE) DC Differential Output Voltage IDD in Shutdown VO(DIFF) ISD CONDITION VDD =3.3V Stereo BTL VDD = 5V Stereo BTL VDD = 5V,Gain = 2 VDD = 5V MIN TYP MAX --------- 7 8 5 2 13 16 50 5 MIN TYP MAX --------------------------- 1.8 1.2 2 1.4 500 150 10 20 60 75 85 82 80 --------------------------- ------- 2 90 55 ------- UNIT mA mV µA (AC Operation Characteristics, VDD = 5.0V, TA=+25°C, RL = 4Ω, unless otherwise noted) PARAMETER Output power (each channel) see Note Total harmonic distortion plus noise Maximum output power bandwidth Phase margin Power supply ripple rejection Mute attenuation Channel-to-channel output separation IN1 /IN2 input separation Input impedance Signal-to-noise ratio Output noise voltage SYMBOL P(OUT) THD+N BOM PSRR CONDITION THD = 1%, BTL, RL = 4Ω THD = 1%, BTL, RL = 8Ω THD = 10%, BTL, RL = 4Ω THD = 10%, BTL, RL = 8Ω PO = 1.6W, BTL, RL = 4Ω PO = 1W, BTL, RL = 8Ω VI = 1V, RL = 10KΩ, G = 1 G = 1, THD =1% RL = 4Ω, Open Load f = 120Hz f = 1kHz ZI Vn PO = 500mW, BTL Output noise voltage UNIT W m% kHz ° dB dB dB dB MΩ dB µV (rms) Note :Output power is measured at the output terminals of the IC at 1kHz. TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 2 G1432 Global Mixed-mode Technology Inc. (AC Operation Characteristics, VDD = 3.3V, TA=+25°C, RL = 4Ω, unless otherwise noted) PARAMETER Output power (each channel) see Note Total harmonic distortion plus noise Maximum output power bandwidth Phase margin Power supply ripple rejection Mute attenuation SYMBOL P(OUT) THD+N BOM PSRR Channel-to-channel output separation CONDITION MIN TYP MAX THD = 1%, BTL, RL = 4Ω --- 0.8 --- THD = 1%, BTL, RL = 8Ω THD = 10%, BTL, RL = 4Ω THD = 10%, BTL, RL = 8Ω ------- 0.5 1 0.6 ------- PO = 0.7W, BTL, RL = 4Ω PO = 0.45W, BTL, RL = 8Ω VI = 1V, RL = 10KΩ, G = 1 ----- 270 100 ----- --- 10 --- G = 1, THD 1% RL = 4Ω, Open Load ----- 20 60 ----- f = 120Hz ----- 75 85 ----- ° dB dB f = 1kHz --- 80 --- dB --- 80 --- dB MΩ IN1 /IN2 input separation Input impedance ZI Signal-to-noise ratio Output noise voltage Vn UNIT W m% kHz --- 2 --- PO = 500mW, BTL --- 90 --- dB Output noise voltage --- 55 --- µV (rms) Note : Output power is measured at the output terminals of the IC at 1kHz. TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 3 G1432 Global Mixed-mode Technology Inc. Typical Characteristics Table of Graphs FIGURE vs Output Power vs Frequency 1,3,6,9,10,13,16 2,4,5,7,8,11,12,14,15 Output Noise Voltage Supply Ripple Rejection Ratio vs Frequency vs Frequency 16,17 18,19 Crosstalk vs Frequency vs Frequency 20,21 22,23 vs Supply Voltage vs Supply Voltage vs Load Resistance 24 25 26 vs Output Power 27,28 THD +N Total Harmonic Distortion Plus Noise Vn Closed loop Response Supply Current IDD PO Output Power PD Power Dissipation Total Harmonic Distortion Plus Noise vs Output Power Total Harmonic Distortion Plus Noise vs Output Frequency 10 10 5 5 20kHz 2 2 1 Po=1.8W 1 1kHz 0.5 0.5 % % 0.2 0.2 0.1 VDD=5V RL=3Ω BTL 0 .05 0 .02 0 .01 3m 5m 10 m 20m 5 0m 1 00m 20 0m 500 m 1 VDD=5V RL=3Ω BTL Av=-2V/V Po=1.5W 0.1 20 Hz 0 .05 0 .02 2 0 .01 20 3 50 10 0 2 00 5 00 1k 2k 5k W Hz Figure 1 Figure 2 Total Harmonic Distortion Plus Noise vs Output Power Total Harmonic Distortion Plus Noise vs Output Frequency 10 10 k 20k 10 5 5 Av=-4V/V 20kHz 2 2 1 1 1kHz 0.5 Av=-2V/V 0.5 % % 0.2 0.2 0.1 0.1 VDD=5V RL=4Ω BTL 20 Hz 0 .05 0 .02 0 .01 3m 5m 10 m 20m 5 0m 1 00m 20 0m 500 m 1 VDD=5V RL=4Ω BTL Po=1.5W Av=-1V/V 0 .05 0 .02 2 0 .01 20 3 50 10 0 2 00 5 00 1k W Hz Figure 3 Figure 4 2k 5k 10 k 20k TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 4 G1432 Global Mixed-mode Technology Inc. Total Harmonic Distortion Plus Noise vs Output Frequency Total Harmonic Distortion Plus Noise vs Output Power 10 5 2 1 10 VDD=5V RL=4Ω BTL Av=-2V/V VDD=5V RL=8Ω BTL Av=-2V/V 5 Po=1.5W 20kHz 2 1 Po=0.25W 0.5 0.5 % % 0.2 0.2 0.1 0.1 Po=0.75W 0 .05 1kHz 0 .05 0 .02 20Hz 0 .02 0 .01 20 50 10 0 2 00 5 00 1k 2k 5k 10 k 0 .01 3m 20k 5m 10m 20m 5 0m 1 00m Hz 2 1 500 m 1 2 Figure 5 Figure 6 Total Harmonic Distortion Plus Noise vs Output Frequency Total Harmonic Distortion Plus Noise vs Output Frequency 10 5 20 0m 3 W 10 VDD=5V RL=8Ω BTL Av=-2V/V 5 Po=1W 2 1 Po=0.25W 0.5 VDD=5V RL=8Ω BTL Po=1W Av=-4V/V Av=-2V/V 0.5 % % 0.2 0.2 0.1 0.1 Po=0.5W 0 .05 0 .05 0 .02 Av=-1V/V 0 .02 0 .01 20 50 10 0 2 00 5 00 1k 2k 5k 10 k 0 .01 20 20k 50 10 0 2 00 5 00 Hz 1k 2k 5k 10 k 20k Hz Figure 8 Figure 7 Total Harmonic Distortion Plus Noise vs Output Power Total Harmonic Distortion Plus Noise vs Output Power 10 10 5 5 20kHz 20kHz 2 2 1 1 1kHz 0.5 1kHz 0.5 % % 0.2 0.1 0 .05 0 .02 0 .01 1m 0.2 0.1 VDD=3.3V RL=3Ω BTL 2m 5m 20Hz 0 .05 VDD=3.3V RL=4Ω BTL 20Hz 0 .02 1 0m 20 m 50 m 10 0m 2 00 m 500 m 0 .01 1m 1 W 2m 5m 1 0m 20 m 50 m 10 0m 2 00 m 500 m 1 W Figure 9 Figure 10 TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 5 G1432 Global Mixed-mode Technology Inc. Total Harmonic Distortion Plus Noise vs Output Frequency Total Harmonic Distortion Plus Noise vs Output Frequency 10 10 5 2 1 VDD=3.3V RL=4Ω BTL Po=0.65W 5 Av=-4V/V 2 Av=-2V/V 1 VDD=3.3V RL=4Ω BTL Av=-2V/V Po=0.7W 0.5 0.5 % % Po=0.1W 0.2 0.2 Po=0.35W 0.1 0.1 Av=-1V/V 0 .05 0 .05 0 .02 0 .02 0 .01 20 50 10 0 2 00 5 00 1k 2k 5k 10 k 0 .01 20 20k 50 10 0 2 00 5 00 1k 2k 10 10 VDD=3.3V RL=8Ω BTL 5 20kHz 2 5 2 1 1 0.5 0.5 % VDD=3.3V RL=8Ω BTL Po=0.4W Av=-4V/V Av=-2V/V % 1kHz 0.2 0.2 0.1 0.1 0 .05 0 .05 Av=-1V/V 20Hz 0 .02 0 .02 2m 5m 1 0m 20 m 50 m 10 0m 2 00 m 500 m 0 .01 20 1 50 10 0 2 00 Figure 13 1k 2k 5k 10 k 20k Figure 14 Output Noise Voltage vs Frequency Total Harmonic Distortion Plus Noise vs Output Frequency 10 1 5 00 Hz W 2 20k Total Harmonic Distortion Plus Noise vs Output Frequency Total Harmonic Distortion Plus Noise vs Output Power 5 10 k Figure 12 Figure 11 0 .01 1m 5k Hz Hz 100 u 90 u VDD=3.3V RL=8Ω BTL Av=-2V/V 80 u 70 u 60 u Po=0.4W 50 u 40 u 0.5 % V Po=0.1W 0.2 BW=22Hz to 22kHz 30 u A- Weighted Filter 0.1 20 u VDD=5V 0 .05 Po=0.25W RL=4Ω 0 .02 0 .01 20 50 10 0 2 00 5 00 1k 2k 5k 10 k 10 u 20 20k 50 100 2 00 50 0 1k 2k 5k 10k 2 0k Hz Hz Figure 16 Figure 15 TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 6 G1432 Global Mixed-mode Technology Inc. Supply Ripple Rejection Ratio vs Frequency Output Noise Voltage vs Frequency 100u 90u +0 80u -10 T 70u -20 60u -30 50u -40 BW=22Hz to 22kHz 40u V VDD=5V RL=4Ω CB=4.7µF -50 d B 30u A- Weighted Filter -60 -70 -80 20u VDD=3.3V -90 RL=4Ω -100 -110 10u 20 50 100 200 500 1k 2k 5k 10k -120 20 20k 50 100 200 Figure 17 5k 1 0k 20k 5k 10k 20k -20 +0 T -40 2k Crosstalk vs Frequency -25 -10 -30 1k Figure 18 Supply Ripple Rejection Ratio vs Frequency -20 500 Hz Hz VDD=5V RL=4Ω CB=4.7µF -30 -35 -40 -45 VDD=5V Po=1.5W RL=4Ω BTL -50 -50 d B -55 d B -60 -60 -65 -70 L to R -70 -80 -75 -90 -80 -85 -100 -90 -110 -120 20 R to L -95 50 100 20 0 500 Hz 1k 2k 5k 10k -100 20 20k 50 100 200 500 1k 2k Hz Figure 19 Figure 20 Crosstalk vs Frequency Closed Loop Response -20 -25 -30 -35 -40 -45 -50 VDD=3.3V Po=0.75W RL=4Ω BTL -55 d B -60 -65 -70 L to R -75 -80 -85 -90 -95 -100 20 R to L 50 100 200 500 1k 2k 5k 10k 20k Hz Figure 21 Figure 22 TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 7 G1432 Global Mixed-mode Technology Inc. Closed Loop Response Supply Current vs Supply Voltage 10 9 Stereo BTL Supply Current(mA) 8 7 6 5 4 3 2 1 0 3 4 5 Supply Voltage (V) Figure 23 6 Figure 24 Output Power vs Supply Voltage Output Power vs Load Resistance 2.5 2 THD+N=1% BTL Each Channel 1.8 RL=4Ω 1.5 RL=3Ω 1 RL=8Ω THD+N=1% BTL Each Channel VDD=5V 1.6 Po-Output Power(W) Po-Output Power (W) 2 1.4 1.2 1 VDD=3.3V 0.8 0.6 0.4 0.5 0.2 0 0 2.5 3.5 4.5 Supply Voltage (V) 5.5 0 6.5 4 8 Power Dissipation vs Output Power 1.8 24 0.7 RL=3Ω 1.4 Power Dissipation(W) Power Dissipation(W) 1.6 1.2 RL=4Ω 1 0.8 0.6 RL=8Ω 20 28 32 Power Dissipation vs Output Power 0.8 0.2 16 Figure 26 Figure 25 0.4 12 Load Resistance(Ω) VDD=5V BTL Each Channel RL=3Ω 0.6 0.5 RL=4Ω 0.4 RL=8Ω 0.3 VDD=3.3V BTL Each Channel 0.2 0.1 0 0 0 0.5 1 1.5 Po-Output Pow er(W) 2 2.5 0 0.25 0.5 Output Pow er(W) 0.75 1 Figure 28 Figure 27 TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 8 G1432 Global Mixed-mode Technology Inc. Pin Description PIN TSSOP QFN 1,12,13,24 9,10,21,22 NAME I/O GND/HS Ground connection for circuitry, directly connected to thermal pad. 2,9,11 3 6,8,23 24 NC LOUT+ NC O 4 1 LIN1 I 5 2 LIN2 I 6 7 8 3 4 5 LBYPASS LVDD SHUTDOWN 10 14 15 16 7 11 12 13 LOUTMUTE ROUT- 17 18 19 20 14 15 16 17 GND RVDD RBYPASS RIN2 21 18 22 23 19 20 Thermal Pad Thermal Pad IN1 /IN2 FUNCTION I I O I O I I Embedded test mode pin, please keep it floating. Left channel + output in BTL mode Left channel IN1 input, selected when IN1 /IN2 pin is held low. Left channel IN2 input, selected when IN1 /IN2 pin is held high. Connect to voltage divider for left channel internal mid-supply bias. Supply voltage input for left channel and for primary bias circuits. Shutdown mode control signal input, places entire IC in shutdown mode when held high, IDD < 5µA. Left channel - output in BTL mode. Mode control signal input, hold low for activation, hold high for mute. Right channel - output in BTL mode MUX control input, hold high to select in2 inputs (5,20)/(2/17), hold low to select in1 inputs (4,21)/(1,18). Ground connection for circuitry. Supply voltage input for right channel. Connect to voltage divider for right channel internal mid-supply bias. I Right channel in2 input, selected when IN1 /IN2 pin is held high. RIN1 I Right channel lin1 input, selected when IN1 /IN2 pin is held low. ROUT+ VOL O I Right channel + output in BTL mode The output power can be clamped by setting a low bound voltage to this pin. The high bound voltage will be generated internally. The output voltage will be clamped between high/low bound voltages. Then the output power is limited. It is weakly pull-low internally, let this pin floating or tied to GND can deactivate this function. Recommend connecting the Thermal Pad to the GND for excellent power dissipation. Recommended Minimum Footprint QFN4X4-24 TSSOP-24 (FD) TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 9 G1432 Global Mixed-mode Technology Inc. Block Diagram (TSSOP/QFN Pin No.) 20k 21/18 RIN1 20/17 RIN2 19/16 RBYPASS 14/11 8/5 23/20 _ RIGHT MUX ROUT+ 22/19 ROUT- 15/12 RVDD 18/15 IN1/IN2 16/13 + MUTE BIAS CIRCUITS MODES CONTROL CIRCUITS SHUTDOWN VOL 6/3 LBYPASS 5/2 LIN2 4/1 LIN1 LEFT MUX LVDD 7/4 + LOUT- 10/7 _ LOUT+ 3/24 20k Parameter Measurement Information 14/11 8/5 23/20 MUTE IN1/IN2 SHUTDOWN 16/13 VOL LVDD 7/4 RL 4/8/32Ω 6/3 LBYPASS CB 4.7µF CI AC source 5/2 LIN2 4/1 LIN1 LEFT MUX + LOUT- 10/7 _ LOUT+ 3/24 RI RF BTL Mode Test Circuit TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 10 G1432 Global Mixed-mode Technology Inc. Application Circuits (TSSOP-24) GND/HS NC LOUT+ CIR RFL CFR AUDIO SOURCE LIN1 RIR LIN2 LBYPASS RBYPASS SHUTDOWN NC LOUTNC GND/HS 1 24 2 23 3 22 4 21 5 20 6 7 19 G1432 18 8 17 9 16 10 15 11 14 12 13 GND/HS VOL ROUT+ CIL RIN1 RFL RIL RIN2 CFL AUDIO SOURCE LVDD RVDD GND CSR IN1/IN2 ROUTMUTE GND/HS Logical Truth Table Mute IN1 /IN2 Shutdown Input X Low Low High X Low High Low X L/R IN1 L/R IN2 L/R IN1 High High High Low Low Low Low L/R IN2 OUTPUT L/R Out+ L/R Out---Output Output Output Output ---Output Output ------- Mode Shutdown (Mute) BTL BTL Mute Mute TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 11 Global Mixed-mode Technology Inc. G1432 Application Information MUTE and SHUTDOWN Mode Operations The G1432 implements the mute and shutdown mode operations to reduce supply current, IDD, to the absolute minimum level during nonuse periods for battery-power conservation. When the shutdown pin (pin 8/5) is pulled high, all linear amplifiers will be deactivated to mute the amplifier outputs. And the G1432 enters an extra low current consumption state, IDD is smaller than 5µA. If pulling the mute pin (pin 14/11) high, it will force the activated linear amplifier to supply the VDD/2 dc voltage on the output & shutdown the second linear amplifiers to mute the AC performance. In the mute mode operation, the current consumption will be a smaller than BTL modes. Shutdown and Mute pins should never be left unconnected, this floating condition will cause the amplifier operations unpredictable. (TSSOP-24/QFN4X4-24 Pin No.) Input MUX Operation There are two input signal paths – IN1 & IN2. With the prompt setting, the G1432 allows the setting of different gains for different input sources. If setting the IN1 /IN2 pin low, the IN1 input source is selected. When setting the IN1 /IN2 pin high, the IN2 input source is chosen. Bridged-Tied Load Mode Operation The G1432 has two linear amplifiers to drive both ends of the speaker load in Bridged-Tied Load (BTL) mode operation. Figure A shows the BTL configuration. The differential driving to the speaker load means that when one side is slewing up, the other side is slewing down, and vice versa. This configuration in effect will double the voltage swing on the load as compared to a ground reference load. In BTL mode, the peak-to-peak voltage VO(PP) on the load will be two times than a ground reference configuration. The voltage on the load is doubled, this will also yield 4 times output power on the load at the same power supply rail and loading. Another benefit of using differential driving configuration is that BTL operation cancels the dc offsets, which eliminates the dc coupling capacitor that is needed to cancelled dc offsets in the ground reference configuration. Low-frequency performance is then limited only by the input network and speaker responses. Cost and PCB space can be minimized by eliminating the dc coupling capacitors. Maximum Power Clampping Function The G1432 supports the maximum output power clamping function to avoid damaging the speaker when the amplifier output a power beyond the speaker tolerance. The Vol pin (pin 23/20) is weakly pull-low internally. If inputting a non-zero voltage (low boundary voltage) to the Vol pin, the G1432 will generate a high boundary voltage which the difference between the VDD/2 and the high boundary voltage is the same as the difference between the VDD/2 and the low boundary voltage. ( i.e. VOH – VDD/2 = VDD/2 – VOL ) Then the outputs of linear amplifiers will be effectively limited between the high/low boundary voltage, the maximum output power is clamped. By setting the voltage of Vol, the maximum output power can be well controlled. When the maximum power clamping function is not used, the Vol pin should be floated or tied to GND. VDD Vo(PP) VDD RL 2xVo(PP) -Vo(PP) Figure A TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 12 G1432 Global Mixed-mode Technology Inc. Optimizing DEPOP Operation Circuitry has been implemented in the G1432 to minimize the amount of popping heard at power-up and when coming out of shutdown mode. Popping occurs whenever a voltage step is applied to the speaker and making the differential voltage generated at the two ends of the speaker. To avoid the popping heard, the bypass capacitor should be chosen promptly, 1/(CBx100kΩ) ≦ 1/(CI*(RI+RF)). Where 100kΩ is the output impedance of the mid-rail generator, CB is the mid-rail bypass capacitor, CI is the input coupling capacitor, RI is the input impedance, RF is the gain setting impedance which is on the feedback path. CB is the most important capacitor. Besides it is used to reduce the popping, CB can also determine the rate at which the amplifier starts up during startup or recovery from shutdown mode. VDD 100 kΩ 50 kΩ Bypass 100 kΩ Figure B De-popping circuitry of the G1432 is shown on Figure B. The PNP transistor limits the voltage drop across the 50kΩ by slewing the internal node slowly when power is applied. At start-up, the voltage at BYPASS capacitor is 0. The PNP is ON to pull the mid-point of the bias circuit down. So the capacitor sees a lower effective voltage, and thus the charging is slower. This appears as a linear ramp (while the PNP transistor is conducting), followed by the expected exponential ramp of an R-C circuit. TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 13 G1432 Global Mixed-mode Technology Inc. Package Information C D 24 L D1 E1 E E2 1 Note 5 θ A2 A A1 e b TSSOP-24 (FD) Package NOTE: 1. Package body sizes exclude mold flash protrusions or gate burrs 2. Tolerance ±0.1mm unless otherwise specified 3. Coplanarity : 0.1mm 4. Controlling dimension is millimeter. Converted inch dimensions are not necessarily exact. 5. Die pad exposure size is according to lead frame design. 6. Follow JEDEC MO-153 SYMBOLS A A1 A2 b C D D1 E E1 E2 e L θ MIN ----0.00 0.80 0.19 0.20 7.7 4.4 4.30 2.7 0.45 0° DIMENSION IN MM NOM --------1.00 --------7.8 ----6.40 BSC 4.40 ----0.65 BSC 0.60 ----- MAX MIN 1.20 0.15 1.05 0.30 ----7.9 4.9 ----0.000 0.031 0.007 0.008 0.303 0.173 4.50 3.2 0.169 0.106 0.75 8° 0.018 0° DIMENSION IN INCH NOM --------0.039 --------0.307 ----0.252 BSC 0.173 ----0.026 BSC 0.024 ----- MAX 0.047 0.006 0.041 0.012 ----0.311 0.193 0.177 0.126 0.030 8° TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 14 G1432 Global Mixed-mode Technology Inc. D2 Pin 1 Dot By Marking D b Pin #1 Identification Chamfer 0.3 X 45° L e E E2 Top View e1 A A2 A1 QFN4X4-24 Package SYMBOL A A1 A2 b D D2 E E2 e e1 L MIN. DIMENSION IN MM NOM. 0.700 0.000 0.178 0.225 3.950 2.650 3.950 2.650 0.350 --------0.203 0.250 4.000 2.700 4.000 2.700 0.500 BSC 2.500 REF 0.400 MAX. MIN. 1.000 0.050 0.228 0.275 4.050 2.750 4.050 2.750 0.028 0.000 0.007 0.009 0.156 0.104 0.156 0.104 0.450 0.014 DIMENSION IN INCH NOM. MAX. --------0.008 0.010 0.157 0.106 0.157 0.106 0.020 BSC 0.098 REF 0.016 0.039 0.002 0.009 0.011 0.159 0.108 0.159 0.108 0.018 Taping Specification Feed Direction Typical TSSOP Package Orientation PACKAGE Q’TY/REEL TSSOP-24 (FD) QFN4X4-24 2,500 ea 3,000 ea Feed Direction Typical QFN Package Orientation GMT Inc. does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and GMT Inc. reserves the right at any time without notice to change said circuitry and specifications. TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 1.1 Jun 21, 2006 15