AP4809 Stereo Headphone Amplifier With Shutdown Mode Features General Description - Operate from 3V to 7V Single Supply Voltage - High Signal-to-Noise ratio - High Slew Rate - Large Output Voltage Swing - Low Distortion - Low Power Consumption - Switch On/Off Click suppression - Excellent Power Supply Ripple Rejection - SOP-8, PDIP-8 and MSOP-8 Pb-Free Packages The AP4809 is a stereo power amplifier in an 8-pin SOP package capable of delivering 70mW continuous average power per channel into 32Ω loads with less than 0.1% (THD+N) from a 5V power supply. Amplifier gain is externally configured by means of two resistors per input channel. It was designed specially to provide high quality output power with a minimal amount of external components and is therefore optimally suited for low-power portable systems. Applications - CD-ROM, DVD-ROM - MP3 Player - Battery Powered Devices - Personal Computers Pin Descriptions Pin Assignments (Top View) Vo1 1 8 VDD IN1- 2 BYPASS 3 7 6 Vo2 IN2- GND 4 5 SHUTDOWN SOP-8L/PDIP-8L (Top View) Vo1 IN1BYPASS GND 8 VDD 7 Vo2 6 IN25 SHUTDOWN 1 2 3 4 Pin No. 1 2 Pin Name Description Vo1 IN1- 3 BYPASS 4 GND 5 SHUTDOWN 6 7 8 IN2Vo2 VDD Output 1 Inverting input 1 Tap to voltage divider for internal mid-rail bias supply. Ground Logic low to put chip in shutdown mode. Inverting input 2 Output 2 Positive power supply MSOP-8L Ordering Information AP4809 X X Package Packing Blank : Tube A : Taping S : SOP-8L N: PDIP-8L M: MSOP-8L This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sale of the product. Rev. 1.0 Sep 29, 2004 1/9 AP4809 Stereo Headphone Amplifier With Shutdown Mode Absolute Maximum Ratings (TA=25oC) Symbol VDD TJ TS TA TSTG VESD PD Parameter Supply Voltage Junction Temperature Soldering Temperature, 10 Seconds Operating Ambient Temperature Range Storage Temperature Range ESD Susceptibility (Note 1) Package Power Dissipation Max. Unit 7 150 250 -40 to 85 -65 to 150 2000 500 V C o C o C o C V mW o Note 1: Human Body Model, C=100pF, R=1500Ω, 3 positive pulses and 3 Negative Pulses. Electrical Characteristics (TA=25oC, VDD=5V, fi=1KHz, RL=32Ω) Symbol VDD IDD PTOT VI(OS) IBIAS VCM GV IO VSHUT VSHUT RO VO PSRR αS Parameter Supply Voltage Supply Current Total Power Dissipation Input Offset Voltage Input Bias Current Common Mode Voltage Open-Loop Voltage Gain Max. Output Current Shutdown Enabled Shutdown Disabled Output Resistance Output Voltage Swing Test Condition VIN=0V, IO=0A VIN=0V, IO=0A VIN=0V RL=5KΩ THD+N < 0.1% Shutdown Pin Voltage Shutdown Pin Voltage RL=16Ω, THD+N=0.1% RL=32Ω, THD+N=0.1% Power Supply Ripple Rejection Channel Separation RL=32Ω R =32Ω THD+N Total Harmonic Distortion + Noise L VO=3.2VP-P (at 0 dB) SNR Signal-TO-Noise Ratio VO=3.2VP-P (at 0 dB) fG Unity Gain Frequency Open Loop, RL=5KΩ PO Output Power RL=32Ω, THD+N=0.1% SR Slew Rate Unity Gain Inverting Anachip Corp www.anachip.com.tw Min. Typ. Max. Unit 2.5 0 0.9 0.24 0.12 - 3 10 5 10 80 80 0.3 75 80 5.5 5 20 3.5 0.7 4.43 4.69 - V mA mW mV pA V dB mA V V Ω V V dB dB - 0.02 - % - 105 6 75 6 - dB MHz mW V/µs Rev. 1.0 Sep 29, 2004 2/9 AP4809 Stereo Headphone Amplifier With Shutdown Mode Typical Performance Characteristics Anachip Corp www.anachip.com.tw Rev. 1.0 Sep 29, 2004 3/9 AP4809 Stereo Headphone Amplifier With Shutdown Mode Typical Performance Characteristics Test Circuit Rf 450K Ω Ri Vi1 CI 10uF VDD / 2 8 CS 100uF Vo1 1 + CB 10uF Ri Vi2 2 IN1- VDD 450K Ω + 6 IN2- - Shutdown Control 5 SHUTDOWN Vo2 Vo1 CC 220uF 100 Ω 7 20KΩ CI 10uF From Shutdown Control Circuit 20KΩ 3 BYPASS VDD CS 0.1uF Vo2 CC 220uF 100 Ω 4 Rf Anachip Corp www.anachip.com.tw Rev. 1.0 Sep 29, 2004 4/9 AP4809 Stereo Headphone Amplifier With Shutdown Mode Application Information 1. Input Capacitor, CI In the typical application, an input capacitor, Ci, is required to allow the amplifier to bias the input signal to the proper dc level for optimum operation. In this case, Ci and Ri form a high-pass filter with the corner frequency determined in following equation (1). fco(highpass) = 1 2π R i C i 3. Mid-rail Bypass Capacitor, CB In the consideration of reducing the start-up pop, the mid-rail voltage should rise at a sub-sonic rate; that is, less than the rise time of 20Hz waveform and slower than the charging rate of both Ci & CC. The relationship shown in equation (3) should be maintained to keep the noise as low as possible. Where CB is the value of bypass capacitor and RSOURCE is the equivalent source impedance of the voltage divider (the parallel combination of the two resistors) (1) The value of Ci is important to consider, as it directly affects the low frequency performance of the circuit. Consider the example where Ri is 15kΩ and the specification calls for a flat bass response down to 20Hz. Equation (1) is reconfigured as below: Ci = 1 2π R i f co(highpass) 1 C B × R SOURCE < 1 Ci R i << 1 RL R C (3) The bypass capacitor, CB, serves several important functions. During start-up, CB determines the rate at which the amplifier starts up. This helps to push the start-up pop noise into the sub-audible range (so slow it can not be heard). The second function is to reduce noise produced by the power supply caused by coupling into the output drive signal. This noise is from the mid-rail generation circuit internal to the amplifier. The capacitor is fed from the resistor divider with equivalent resistance of RSOURCE. On selection of bypass capacitor, CB, ceramic or tantalum low-ESR capacitors are recommended for the best THD and noise performance. (2) In this example, Ci is 0.5 µF, so one would likely choose a value in the range of 1µF to 2.2µF. A further consideration for this capacitor is the leakage path from the input source through the input network (Ri, Ci) and the feedback resistor (Rf) to the load. This leakage current creates a dc offset voltage at the input to the amplifier that reduces useful headroom, especially in high-gain applications (>10). For this reason a low-leakage tantalum or ceramic capacitor is the best choice. When polarized capacitors are used, the positive side of the capacitor should face the amplifier input in most applications, as the dc level there is held at VDD/2, which is likely higher than the source dc level. It is important to confirm the capacitor polarity in the application. 4. Output Coupling Capacitor, CC In the typical single-supply single-ended (SE) configuration, an output coupling capacitor (CC) is required to block the dc bias at the output of the amplifier, thus preventing dc currents in the load. As with the input coupling capacitor, the output coupling capacitor and impedance of the load form a high-pass filter governed by equation (4). 2. Power Supply Decoupling, CS The AP4809 is a high-performance CMOS audio amplifier that requires adequate power supply decoupling to ensure that the output total harmonic distortion (THD) is as low as possible. Power supply decoupling also prevents oscillations for long lead lengths between the amplifier and the speaker. The optimum decoupling is achieved by using two capacitors of different types that target different types of noise on the power supply leads. For higher frequency transients, spikes, or digital hash on the line, a good low equivalent-series-resistance (ESR) ceramic capacitor, typically 0.1µF, placed as close as possible to the device VDD lead, works best. For filtering lower-frequency noise signals, a larger aluminum electrolytic capacitor of 10µF or greater placed near the power amplifier is recommended. f(out high) = 1 2π R L C C (4) The main disadvantage, from a performance standpoint, is that the typically small load impedances drive the low-frequency corner higher. Large values of CC are required to pass low frequencies into the load. The output coupling capacitor required in single-supply SE mode also places additional constraints on the selection of other components in the amplifier circuit. With the rules described earlier still valid, add the following relationship: Anachip Corp www.anachip.com.tw Rev. 1.0 Sep 29, 2004 5/9 AP4809 Stereo Headphone Amplifier With Shutdown Mode Application Information (Continued) 4.2 Using Low-ESR Capacitors Low-ESR capacitors are recommended throughout this application. A real capacitor can be modeled simply as a resistor in series with an ideal capacitor. The voltage drop across this resistor minimizes the beneficial effects of the capacitor in the circuit. The lower the equivalent value of this resistance, the more the real capacitor behaves like an ideal capacitor. 4.1 Output Pull-Down Resistor, RC + RO Placing a 100Ω resistor, RC, from the output side of the coupling capacitor to ground insures the coupling capacitor, CC, is charged before a plug is inserted into the jack. Without this resistor, the coupling capacitor would charge rapidly upon insertion of a plug, leading to an audible pop in the headphones. Placing a 20kΩ resistor, RO, from the output of the IC to ground insures that the coupling capacitor fully discharges at power down. If the supply is rapidly cycled without this capacitor, a small pop may be audible in 10kΩ loads. Marking Information ( Top View ) 8 5 (Top View) Logo Part number YY WW X 4 4809 ID code: internal Xth week: 01~52 Year: "01" = 2001 "02" = 2002 ID code: internal Date code: Y: Year : 0~9 M: Month (A~L) ~ 1 YM X Logo Part number AP4809 SOP-8L/PDIP-8L MSOP-8L Anachip Corp www.anachip.com.tw Rev. 1.0 Sep 29, 2004 6/9 AP4809 Stereo Headphone Amplifier With Shutdown Mode Package Information H E (1) Package Type: SOP-8L L VIEW "A" D 0.015x45 C B A1 e 7 (4X) A A2 7 (4X) VIEW "A" y Symbol A A1 A2 B C D E e H L y θ Dimensions In Millimeters Min. Nom. Max. 1.40 1.60 1.75 0.10 0.25 1.30 1.45 1.50 0.33 0.41 0.51 0.19 0.20 0.25 4.80 5.05 5.30 3.70 3.90 4.10 1.27 5.79 5.99 6.20 0.38 0.71 1.27 0.10 0O 8O Anachip Corp www.anachip.com.tw Dimensions In Inches Min. Nom. Max. 0.055 0.063 0.069 0.040 0.100 0.051 0.057 0.059 0.013 0.016 0.020 0.0075 0.008 0.010 0.189 0.199 0.209 0.146 0.154 0.161 0.050 0.228 0.236 0.244 0.015 0.028 0.050 0.004 0O 8O Rev. 1.0 Sep 29, 2004 7/9 AP4809 Stereo Headphone Amplifier With Shutdown Mode Package Information(Continued) (2) Package Type: PDIP-8L D E1 E-PIN O0.118 inch E 15 (4X) PIN #1 INDENT O0.025 DEEP 0.006-0.008 inch C 7 (4X) A1 L A A2 eB B S Symbol A A1 A2 B B1 B2 C D E E1 e L eB S e B1 B2 Dimensions in millimeters Min. Nom. Max. 5.33 0.38 3.1 3.30 3.5 0.36 0.46 0.56 1.4 1.52 1.65 0.81 0.99 1.14 0.20 0.25 0.36 9.02 9.27 9.53 7.62 7.94 8.26 6.15 6.35 6.55 2.54 2.92 3.3 3.81 8.38 8.89 9.40 0.71 0.84 0.97 Anachip Corp www.anachip.com.tw Dimensions in inches Min. Nom. Max. 0.210 0.015 0.122 0.130 0.138 0.014 0.018 0.022 0.055 0.060 0.065 0.032 0.039 0.045 0.008 0.010 0.014 0.355 0.365 0.375 0.300 0.313 0.325 0.242 0.250 0.258 0.100 0.115 0.130 0.150 0.330 0.350 0.370 0.028 0.033 0.038 Rev. 1.0 Sep 29, 2004 8/9 AP4809 Stereo Headphone Amplifier With Shutdown Mode Package Information (Continued) GAGE PLANE L 0.25 E E1 (3) Package Type: MSOP-8L D DETAIL A PIN 1 INDICATORφ 0.45 mm × 0.038DP SURFACE POLISHED DETAIL A A A2 12 (4x) A1 θ b Symbol A A1 A2 b C D E E1 e L y θ C e y Dimensions In Millimeters Min. Nom. Max. 0.81 1.02 1.22 0.05 0.15 0.76 0.86 0.97 0.28 0.30 0.38 0.13 0.15 0.23 2.90 3.00 3.10 4.80 4.90 5.00 2.90 3.00 3.10 0.65 0.40 0.53 0.66 0.076 0º 3º 6º Anachip Corp www.anachip.com.tw Dimensions In Inches Min. Nom. Max. 0.032 0.040 0.048 0.002 0.006 0.030 0.034 0.038 0.011 0.012 0.015 0.005 0.006 0.009 0.114 0.118 0.122 0.189 0.193 0.197 0.114 0.118 0.122 0.0256 0.016 0.021 0.026 0.003 0º 3º 6º Rev. 1.0 Sep 29, 2004 9/9