G1432

Global Mixed-mode Technology Inc. G1432 2W Stereo Audio Amplifier Features 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 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. 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 ORDER MARKING NUMBER G1432F3U G1432Q5U G1432 G1432 TEMP. RANGE -40°C to +85°C PACKAGE (Pb free) QFN4X4-24 -40°C to +85°C TSSOP-24 (FD) Note: F3:TSSOP-24 (FD) Q5:QFN4X4-24 U: Tape & Reel Pin Configuration RBYPBASS RIN1 RIN2 RVDD G1432 G1432 GND/HS NC LOUT+ LIN1 LIN2 LBYPASS LVDD SHUTDOWN NC 1 2 3 4 5 6 7 8 9 24 23 22 21 20 19 18 17 16 15 14 13 GND/HS VOL ROUT+ RIN1 RIN2 RBYPASS RVDD GND IN1/IN2 ROUTMUTE GND/HS ROUT+ VOL GND/HS 19 20 21 22 23 24 17 16 15 14 GND 18 13 12 11 IN1/IN2 ROUTMUTE GND/HS GND/HS NC LOUT- Thermal Pad GND/HS NC LOUT+ Thermal Pad 10 9 8 7 LIN1 LBYPASS GND/HS 12 Top View TSSOP-24 (FD) Bottom View G1432 QFN4X4-24 Note: Recommend connecting the Thermal Pad to the GND for excellent power dissipation. Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 1 SHUTDOWN LVDD LIN2 NC LOUT- 10 NC 11 2 5 1 3 4 6 Global Mixed-mode Technology Inc. Absolute Maximum Ratings 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) (2) G1432 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) : Recommended PCB Layout. : Human body model : C = 100pF, R = 1500Ω, 3 positive pulses plus 3 negative pulses Electrical Characteristics DC Electrical Characteristics, TA=+25°C PARAMETER Supply Current in Mute Mode DC Differential Output Voltage IDD in Shutdown SYMBOL IDD(MUTE) VO(DIFF) ISD CONDITION VDD =3.3V Stereo BTL VDD = 5V Stereo BTL VDD = 5V,Gain = 2 VDD = 5V MIN --------- TYP 7 8 5 2 MAX 13 16 50 5 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 SYMBOL P(OUT) 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 MIN --------------------------------- TYP 1.8 1.2 2 1.4 500 150 10 20 60 75 85 82 80 2 90 55 MAX --------------------------------- UNIT W 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 THD+N BOM PSRR m% kHz ° dB dB dB dB MΩ dB µV (rms) ZI Vn PO = 500mW, BTL Output noise voltage Note :Output power is measured at the output terminals of the IC at 1kHz. Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 2 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 G1432 TYP 0.8 0.5 1 0.6 270 100 10 20 60 75 85 80 80 2 90 55 SYMBOL P(OUT) CONDITION THD = 1%, BTL, RL = 4Ω THD = 1%, BTL, RL = 8Ω THD = 10%, BTL, RL = 4Ω THD = 10%, BTL, RL = 8Ω PO = 0.7W, BTL, RL = 4Ω PO = 0.45W, BTL, RL = 8Ω VI = 1V, RL = 10KΩ, G = 1 G = 1, THD 1% RL = 4Ω, Open Load f = 120Hz f = 1kHz MIN ----------------------------- MAX --------------------------------- UNIT W 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 THD+N BOM PSRR m% kHz ° dB dB dB dB MΩ dB µV (rms) Input impedance Signal-to-noise ratio Output noise voltage ZI PO = 500mW, BTL Vn Output noise voltage ----- Note : Output power is measured at the output terminals of the IC at 1kHz. Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 3 Global Mixed-mode Technology Inc. Typical Characteristics Table of Graphs FIGURE THD +N Total Harmonic Distortion Plus Noise Output Noise Voltage Supply Ripple Rejection Ratio Crosstalk Closed loop Response Supply Current vs Output Power vs Frequency vs Frequency vs Frequency vs Frequency vs Frequency vs Supply Voltage vs Supply Voltage vs Load Resistance vs Output Power 1,3,6,9,10,13,16 2,4,5,7,8,11,12,14,15 16,17 18,19 20,21 22,23 24 25 26 27,28 G1432 Vn IDD PO Output Power PD Power Dissipation Total Harmonic Distortion Plus Noise vs Output Power 10 5 10 5 Total Harmonic Distortion Plus Noise vs Output Frequency 20kHz 2 1 0.5 % 0.2 0.1 0 .05 2 1 Po=1.8W 1kHz % 0.5 0.2 0.1 20 Hz Po=1.5W 0 .02 0 .01 3m VDD=5V RL=3Ω BTL 20m 5 0m 1 00m W 20 0m 500 m 1 2 3 0 .05 VDD=5V RL=3Ω BTL A v=-2V/V 0 .02 0 .01 20 5m 10 m 50 10 0 2 00 5 00 Hz 1k 2k 5k 10 k 20k Figure 1 Figure 2 Total Harmonic Distortion Plus Noise vs Output Power 10 5 10 5 Total Harmonic Distortion Plus Noise vs Output Frequency 2 1 0.5 % 0.2 0.1 0 .05 20kHz A v=-4V/V 2 1 A v=-2V/V 1kHz % 0.5 0.2 0.1 20 Hz 0 .02 0 .01 3m VDD=5V RL=4Ω BTL 20m 5 0m 1 00m W 20 0m 500 m 1 2 3 A v=-1V/V 0 .05 0 .02 0 .01 20 VDD=5V RL=4Ω BTL Po=1.5W 1k 2k 5k 10 k 20k 5m 10 m 50 10 0 2 00 5 00 Hz Figure 3 Figure 4 Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 4 Global Mixed-mode Technology Inc. Total Harmonic Distortion Plus Noise vs Output Frequency 10 5 10 G1432 VDD=5V RL=8Ω BTL A v=-2V/V Total Harmonic Distortion Plus Noise vs Output Power 5 2 1 0.5 % 0.2 0.1 0 .05 VDD=5V RL=4Ω BTL A v=-2V/V Po=1.5W Po=0.25W % 2 1 0.5 20kHz 0.2 0.1 1kHz Po=0.75W 0 .05 0 .02 0 .01 20 0 .02 0 .01 3m 20Hz 5m 10m 20m 5 0m 1 00m W 20 0m 500 m 1 2 3 50 10 0 2 00 5 00 Hz 1k 2k 5k 10 k 20k Figure 5 Figure 6 Total Harmonic Distortion Plus Noise vs Output Frequency 10 5 10 Total Harmonic Distortion Plus Noise vs Output Frequency 5 2 1 0.5 % 0.2 0.1 0 .05 VDD=5V RL=8Ω BTL A v=-2V/V Po=0.25W Po=1W 2 1 0.5 % 0.2 0.1 VDD=5V RL=8Ω BTL Po=1W A v=-2V/V A v=-4V/V Po=0.5W 0 .05 0 .02 0 .01 20 0 .02 0 .01 20 A v=-1V/V 50 10 0 2 00 5 00 Hz 1k 2k 5k 10 k 20k 50 10 0 2 00 5 00 Hz 1k 2k 5k 10 k 20k Figure 7 Figure 8 Total Harmonic Distortion Plus Noise vs Output Power 10 5 10 5 Total Harmonic Distortion Plus Noise vs Output Power 20kHz 2 1 0.5 % 0.2 0.1 0 .05 2 1 20kHz 1kHz % 0.5 1kHz 0.2 0.1 0 .02 0 .01 1m VDD=3.3V RL=3Ω BTL 2m 5m 1 0m 20Hz 0 .05 VDD=3.3V RL=4Ω BTL 20Hz 0 .02 0 .01 1m 20 m W 50 m 10 0m 2 00 m 500 m 1 2m 5m 1 0m 20 m W 50 m 10 0m 2 00 m 500 m 1 Figure 9 Figure 10 Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 5 Global Mixed-mode Technology Inc. Total Harmonic Distortion Plus Noise vs Output Frequency 10 5 10 5 G1432 Total Harmonic Distortion Plus Noise vs Output Frequency 2 1 0.5 % 0.2 0.1 0 .05 VDD=3.3V RL=4Ω BTL Po=0.65W A v=-4V/V A v=-2V/V 2 1 0.5 % 0.2 0.1 VDD=3.3V RL=4Ω BTL A v=-2V/V Po=0.7W Po=0.1W Po=0.35W A v=-1V/V 0 .05 0 .02 0 .01 20 0 .02 0 .01 20 50 10 0 2 00 5 00 Hz 1k 2k 5k 10 k 20k 50 10 0 2 00 5 00 Hz 1k 2k 5k 10 k 20k Figure 11 Figure 12 Total Harmonic Distortion Plus Noise vs Output Power 10 5 10 Total Harmonic Distortion Plus Noise vs Output Frequency 5 2 1 0.5 % 0.2 0.1 0 .05 20kHz VDD=3.3V RL=8Ω BTL 2 1 0.5 VDD=3.3V RL=8Ω BTL Po=0.4W A v=-2V/V A v=-4V/V 1kHz % 0.2 0.1 0 .05 20Hz 0 .02 0 .01 1m 0 .02 0 .01 20 A v=-1V/V 2m 5m 1 0m 20 m W 50 m 10 0m 2 00 m 500 m 1 50 10 0 2 00 5 00 Hz 1k 2k 5k 10 k 20k Figure 13 Figure 14 Total Harmonic Distortion Plus Noise vs Output Frequency 10 5 Output Noise Voltage vs Frequency 100 u 90 u 80 u 70 u 60 u 2 1 0.5 % 0.2 0.1 VDD=3.3V RL=8Ω BTL A v=-2V/V Po=0.4W 50 u 40 u V BW=22Hz to 22kHz 30 u Po=0.1W A - Weighted Filter 20 u 0 .05 VDD=5V Po=0.25W RL=4Ω 10 u 20 0 .02 0 .01 20 50 10 0 2 00 5 00 Hz 1k 2k 5k 10 k 20k 50 100 2 00 50 0 Hz 1k 2k 5k 10k 2 0k Figure 15 Figure 16 Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 6 Global Mixed-mode Technology Inc. Output Noise Voltage vs Frequency 100u 90u 80u 70u 60u 50u 40u V +0 -10 -20 -30 -40 G1432 Supply Ripple Rejection Ratio vs Frequency T VDD=5V RL=4Ω CB=4.7µF BW=22Hz to 22kHz d B -50 -60 -70 -80 30u A - Weighted Filter 20u VDD=3.3V RL=4Ω 10u 20 50 100 200 500 Hz 1k 2k 5k 10k 20k -90 -100 -110 -120 20 50 100 200 500 Hz 1k 2k 5k 1 0k 20k Figure 17 Figure 18 Supply Ripple Rejection Ratio vs Frequency +0 -10 -20 -30 -40 -50 d B -60 -70 -80 -90 -100 -110 -120 20 Crosstalk vs Frequency -20 -25 T VDD=5V RL=4Ω CB=4.7µF -30 -35 -40 -45 -50 -55 d B -60 -65 -70 -75 -80 -85 -90 -95 -100 20 VDD=5V Po=1.5W RL=4Ω BTL L to R R to L 50 100 200 500 Hz 1k 2k 5k 10k 20k 50 100 20 0 500 Hz 1k 2k 5k 10k 20k Figure 19 Figure 20 Crosstalk vs Frequency -20 -25 -30 -35 -40 -45 -50 -55 d B -60 -65 -70 -75 -80 -85 -90 -95 -100 20 Closed Loop Response VDD=3.3V Po=0.75W RL=4Ω BTL L to R R to L 50 100 200 500 Hz 1k 2k 5k 10k 20k Figure 21 Figure 22 Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 7 Global Mixed-mode Technology Inc. G1432 Supply Current vs Supply Voltage Closed Loop Response 10 9 8 Supply Current(mA) 7 6 5 4 3 2 1 0 3 Stereo BTL Figure 23 4 5 Supply Voltage (V) 6 Figure 24 Output Power vs Supply Voltage 2.5 THD+N=1% BTL Each Channel RL=4Ω 1.5 RL=3Ω 1 RL=8Ω 0.5 2 1.8 1.6 Po-Output Power(W) 1.4 1.2 1 0.8 0.6 0.4 0.2 0 2.5 3.5 4.5 Supply Voltage (V) 5.5 6.5 0 0 Output Power vs Load Resistance 2 Po-Output Power (W) VDD=5V THD+N=1% BTL Each Channel VDD=3.3V 4 8 12 16 20 24 28 32 Load Resistance( Ω) Figure 25 Figure 26 Power Dissipation vs Output Power 1.8 1.6 Power Dissipation(W) 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 0.5 1 1.5 Po-Output Pow er(W) 2 2.5 RL=8Ω VDD=5V BTL Each Channel RL=4Ω RL=3Ω Power Dissipation(W) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0 Power Dissipation vs Output Power RL=3Ω RL=4Ω RL=8Ω VDD=3.3V BTL Each Channel 0.25 0.5 Output Pow er(W) 0.75 1 Figure 27 Figure 28 Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 8 Global Mixed-mode Technology Inc. Pin Description PIN TSSOP 2,9,11 3 4 G1432 FUNCTION QFN 6,8,23 24 1 NAME GND/HS NC LOUT+ LIN1 I/O NC O I 1,12,13,24 9,10,21,22 Ground connection for circuitry, directly connected to thermal pad. 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. 5 6 7 8 10 14 15 16 17 18 19 20 21 22 23 2 3 4 5 7 11 12 13 14 15 16 17 18 19 20 LIN2 LBYPASS LVDD SHUTDOWN LOUTMUTE ROUTIN1 /IN2 I I I O I O I 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. Right channel in2 input, selected when IN1 /IN2 pin is held high. Right channel lin1 input, selected when IN1 /IN2 pin is held low. 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. GND RVDD RBYPASS RIN2 RIN1 ROUT+ VOL I I I O I Thermal Pad Thermal Pad Recommended Minimum Footprint T SSOP-24 (FD) QFN4X4-24 Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 9 Global Mixed-mode Technology Inc. Block Diagram (TSSOP/QFN Pin No.) G1432 20k 21/18 20/17 RIN1 RIN2 RIGHT MUX _ ROUT+ ROUT- 22/19 15/12 19/16 RBYPASS + RVDD 18/15 14/11 8/5 23/20 MUTE SHUTDOWN VOL BIAS CIRCUITS MODES CONTROL CIRCUITS IN1/IN2 16/13 LVDD LBYPASS + 5/2 4/1 LIN2 LIN1 LEFT LEFT MUX _ LOUTLOUT+ 7/4 6/3 10/7 3/24 20k Parameter Measurement Information 14/11 8/5 23/20 MUTE SHUTDOWN VOL IN1/IN2 16/13 LVDD 6/3 CB 4.7µF CI AC source RI 5/2 4/1 LIN2 LIN1 LEFT MUX LBYPASS 7/4 RL 4/8/32Ω + _ LOUTLOUT+ 10/7 3/24 RF BTL Mode Test Circuit Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 10 Global Mixed-mode Technology Inc. Application Circuits (TSSOP-24) G1432 GND/HS NC LOUT+ CIR RFL CFR AUDIO SOURCE RIR 1 2 3 4 5 6 19 8 9 10 11 12 24 23 22 21 20 7 GND/HS GND/HS VOL ROUT+ RIN1 RIL CIL RFL AUDIO SOURCE CFL LIN1 LIN2 RIN2 LVDD RVDD GND IN1/IN2 ROUTMUTE GND/HS CSR LBYPASS RBYPASS SHUTDOWN NC LOUTNC GND/HS G1432 18 17 16 15 14 13 Logical Truth Table Mute X Low Low High IN1 /IN2 X Low High Low Shutdown High Low Low Low Low Input X L/R IN1 L/R IN2 L/R IN1 OUTPUT L/R Out+ L/R Out---Output Output Output Output ---Output Output ------- Mode Shutdown (Mute) BTL BTL Mute Mute High High L/R IN2 Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 11 Global Mixed-mode Technology Inc. Application Information (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. VDD VDD G1432 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. 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. Vo(PP) RL 2xVo(PP) -Vo(PP) VDD Figure A Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 12 Global Mixed-mode Technology Inc. Optimizing DEPOP Operation G1432 VDD 100 kΩ 50 kΩ 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. 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. Bypass Bypass 100 kΩ Figure B Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 13 Global Mixed-mode Technology Inc. Package Information C G1432 L D 24 24 D1 E1 E E2 1 Note 5 θ A2 A1 e b A 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 1.20 0.15 1.05 0.30 ----7.9 4.9 4.50 3.2 0.75 8° MIN ----0.000 0.031 0.007 0.008 0.303 0.173 0.169 0.106 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° Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 14 Global Mixed-mode Technology Inc. G1432 D2 b Pin #1 Identification Chamfer 0.3 X 45° Pin 1 Dot By Marking D 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. 0.700 0.000 0.178 0.225 3.950 2.650 3.950 2.650 DIMENSION IN MM NOM. --------0.203 0.250 4.000 2.700 4.000 2.700 0.500 BSC 2.500 REF 0.400 MAX. 1.000 0.050 0.228 0.275 4.050 2.750 4.050 2.750 MIN. 0.028 0.000 0.007 0.009 0.156 0.104 0.156 0.104 DIMENSION IN INCH NOM. --------0.008 0.010 0.157 0.106 0.157 0.106 0.020 BSC 0.098 REF 0.016 MAX. 0.039 0.002 0.009 0.011 0.159 0.108 0.159 0.108 0.350 0.450 0.014 0.018 Taping Specification PACKAGE TSSOP-24 (FD) QFN4X4-24 Feed Feed Direction Typical TSSOP Package Orientation Feed Direction Typical QFN Package Orientation Q’TY/REEL 2,500 ea 3,000 ea 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. Ver: 1.1 Jun 21, 2006 TEL: 886-3-5788833 http://www.gmt.com.tw 15