A Product Line of Diodes Incorporated PAM8302A 2.5W FILTERLESS CLASS-D MONO AUDIO AMPLIFIER Description Pin Assignments The PAM8302A is a 2.5W Class-D mono audio amplifier. Its low THD+N feature offers high quality sound reproduction. The new filterless architecture allows the device to drive speakers directly instead of using low-pass output filters, therefore saving system cost and PCB area. With the same number of external components, the efficiency of the PAM8302A is much better than that of Class-AB cousins. It can optimize battery life thus is ideal for portable applications. The PAM8302A is available in MSOP-8, SOP-8, DFN3x3-8 and DFN2x2-8 packages. Features 2.5W Output at 10% THD with a 4Ω Load and 5V Power Supply Filterless, Low Quiescent Current and Low EMI High Efficiency up to 88% Superior Low Noise Short Circuit Protection Thermal Shutdown, Few External Components to Save Space and Cost MSOP-8, SOP-8, DFN3x3-8 and DFN2x2-8 Packages Available Pb-Free Packages Applications PMP/MP4 GPS Portable Speakers Walkie Talkie Handsfree phones/Speaker Phones Cellular Phones PAM8302A Document number: DSxxxxx Rev. 2 - 5 1 of 14 www.diodes.com April 2013 © Diodes Incorporated A Product Line of Diodes Incorporated PAM8302A Typical Applications Circuit Functional Block Diagram Absolute Maximum Ratings (@TA = +25°C, unless otherwise specified.) These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may affect device reliability. All voltages are with respect to ground. Parameter Supply Voltage at No Input Signal Input Voltage Maximum Junction Temperature Storage Temperature Soldering Temperature PAM8302A Document number: DSxxxxx Rev. 2 - 5 Rating 6.0 Unit -0.3 to VDD +0.3 150 -65 to +150 300, 5sec V °C 2 of 14 www.diodes.com April 2013 © Diodes Incorporated A Product Line of Diodes Incorporated PAM8302A Recommended Operating Conditions (@TA = +25°C, unless otherwise specified.) Parameter Suppy Voltage Range Operation Temperature Range Junction Temperature Range Rating 2.0 to 5.5 -40 to +85 -40 to +125 Unit V °C °C Thermal Information Parameter Package SOP-8 MSOP-8 DFN3x3-8 DFN2x2-8 Thermal Resistance (Junction to Ambient) Symbol θJA Max 115 180 4739 80 Unit °C/W Electrical Characteristics (@TA = +25°C, VIN = 3.6V, VO = 1.8V, CIN = 10µF, COUT = 10µF, L = 4.7µH, unless otherwise specified.) Parameter Supply Voltage Range Symbol Quiescent Current IQ Shutdown Current ISHDN Output Power Peak Efficiency Total Harmonic Distortion Plus Noise Test Conditions PO η THD+N Min No Load 4 VSHDN = 0V f = 1kHz, RL = 4Ω, THD+N = 10% VDD = 5V 2.25 2.50 VDD = 3.6V 1.10 1.25 f = 1kHz, RL = 4Ω, THD+N = 1% VDD = 5V 1.80 2.00 VDD = 3.6V 0.86 0.95 f = 1kHz, RL = 8Ω, THD+N = 10% VDD = 5V 1.35 1.50 VDD = 3.6V 0.72 0.80 f = 1kHz, RL = 8Ω, THD+N = 1% VDD = 5V 1.15 1.30 VDD = 3.6V 0.6 0.65 f = 1kHz Power Supply Ripple Rejection Dynamic Range Signal to Noise Ratio Noise Oscillator Frequency Drain-Source On-State Resistance DYN SNR VN SHDN Input High VSH SHDN Input Low VSL OTP OTH Over Temperature Protection Over Temperature Hysterisis PAM8302A Document number: DSxxxxx Rev. 2 - 5 mA 1 µA W 85 88 0.35 0.45 0.50 RL = 4Ω, PO = 0.1W, f = 1kHz 0.35 0.40 0.40 0.45 24.0 25.5 No Inputs, f = 1kHz, VPP = 200mV f = 20 to 20kHz f = 20 to 20kHz No A-Weighting A-Weighting IDS = 100mA dB 50 dB 90 80 180 120 dB dB 300 200 µV 250 300 kHz 0.45 0.20 0.50 0.25 Ω P MOSFET N MOSFET 0.4 3 of 14 www.diodes.com % 45 1.2 Junction Temperautre % 85 75 200 fOSC RDS(ON) V 8 0.30 22.5 Units 5.5 RL = 8Ω, PO = 0.1W, f = 1kHz GV PSRR Max RL = 8Ω, PO = 0.5W, f = 1kHz RL = 4Ω, PO = 0.5W, f = 1kHz Gain Typ 2.0 VDD 120 135 30 V °C °C April 2013 © Diodes Incorporated A Product Line of Diodes Incorporated PAM8302A Typical Performance Characteristics (@TA = +25°C, unless otherwise specified.) PAM8302A Document number: DSxxxxx Rev. 2 - 5 4 of 14 www.diodes.com April 2013 © Diodes Incorporated A Product Line of Diodes Incorporated PAM8302A Typical Performance Characteristics (cont.) (@TA = +25°C, unless otherwise specified.) PAM8302A Document number: DSxxxxx Rev. 2 - 5 5 of 14 www.diodes.com April 2013 © Diodes Incorporated A Product Line of Diodes Incorporated PAM8302A Typical Performance Characteristics (cont.) (@TA = +25°C, unless otherwise specified.) PAM8302A Document number: DSxxxxx Rev. 2 - 5 6 of 14 www.diodes.com April 2013 © Diodes Incorporated A Product Line of Diodes Incorporated PAM8302A Application Information Test Setup for Performance Testing PAM8302A DUT Notes: 1. The AP AUX-0025 low pass filter is necessary for every class-D amplifier measurement with AP analyzer. 2. Two 22μH inductors are used in series with load resistor to emulate the small speaker for efficiency measurement. Maximum Gain As shown in block diagram (Page 2), the PAM8302A has two internal amplifier stages. The first stage's gain is externally con figurable, while the second stage's is internally fixed. The closedloop gain of the first stage is set by selecting the ratio of RF to RI while the second stage's gain is fixed at 2x.The output of amplifier one serves as the input to amplifier two, thus the two amplifiers produce signals identical in magnitude, but different in phase by 180°. Consequently, the differential gain for the IC is A =20*log [2*(RF/RI)] The PAM8302A sets maximum R =80kΩ, minimum RI =10kΩ, so the maximum closed-gain is 24dB. Input Capacitor (CI) Intypical application, an input capacitor, CI is required to allow the amplifier to bias input signals to a proper DC level for optimum operation. In this case, CI and the minimum input impedance RI (10k internal) form a high pass filter with a corner frequeny determind by the following equation: fC 1 2R I CI It is important to choose the value of CI as it directly affects low frequency performance of the circuit, for example, when an application requires a flat bass response as loas as 100Hz,. Equation is reconfigured as follows: CI 1 2R I f I As the input reisitance is varible, for the CI value of 0.16µF, one should actually choose the CI within the range of 0.1µF to 0.22µF. A further consideration for this capacitor is the leakage path from the input source through the input network (RI, RF, CI) 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 application. For this reason, a low leakage tantalum or ceramic capacitor is the best choice. When a polarized capacitior is used, the positive side of the capacitor should face the amplifier input in most applications as the DC level is held at VDD/2, which is likely higher than the source DC level. Please note that it is important to confirm the capacitor polarity in the application. PAM8302A Document number: DSxxxxx Rev. 2 - 5 7 of 14 www.diodes.com April 2013 © Diodes Incorporated A Product Line of Diodes Incorporated PAM8302A Application Information (cont.) Power Supply Decoupling (CS) The PAM8302A is a high-performance CMOS audio amplifier that requires adequate power supply decoupling to ensure the output THD and PSRR as low as possible. Power supply decoupling affects low frequency response. 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, typicall 1.0µF is good, placing it as close as possilbe to the device VDD terminal. For filtering lower frequency noise signals, capacitor of 10µF or larger, closely located to near the audio power amplifier is recommended. Shutdown Operation In order to reduce shutdown power consumption, the PAM8032A contains shutdown circuitry for turn to turn off the amplifier. This shutdown feature turns the amplifier off when a logic low is apllied on the SD pin. By switching the shutdown pin over to GND, the PAM8302A supply current draw will be minimized inidle mode. For the best power on/off pop performance, the amplifier should be set in the shutdown mode prior to power on/off operation. Under Voltage Lock-Out (UVLO) The PAM8302A incorporates circuitry to detect low on or off voltage. When the supply voltage drops to 2.1V or below, the PAM8302A goes into a state of shutdown, and the device comes out of its shutdown state to normal operation by reset the power supply or SD pin. How to Reduce EMI (Electro Magnetic Interference) A simple solution is to put an additional capacitor 1000μF at power supply terminal for power line coupling if the traces from amplifier to speakers are short (< 20CM). Most applications require a ferrite bead filter as shown at Figure 1. The ferrite filter depresses EMI of around 1MHz and higher. When selecting a ferrite bead, choose one with high impedance at high frequencies and low impedance at low frequencies. Figure 1. Ferrite Bead Filter to Reduce EMI PAM8302A Document number: DSxxxxx Rev. 2 - 5 8 of 14 www.diodes.com April 2013 © Diodes Incorporated A Product Line of Diodes Incorporated PAM8302A Ordering Information Part Number PAM8302AASCR PAM8302AADCR PAM8302AAYCR PAM8302ABGCR Package Type MSOP-8 SOP-8 DFN3x3-8 DFN2x2-8 Standard Package 2500 Units/Tape&Reel 2500 Units/Tape&Reel 3000 Units/Tape&Reel 3000 Units/Tape&Reel Marking Information PAM8302A Document number: DSxxxxx Rev. 2 - 5 9 of 14 www.diodes.com April 2013 © Diodes Incorporated A Product Line of Diodes Incorporated PAM8302A Package Outline Dimensions (All dimensions in mm.) MSOP-8 PAM8302A Document number: DSxxxxx Rev. 2 - 5 10 of 14 www.diodes.com April 2013 © Diodes Incorporated A Product Line of Diodes Incorporated PAM8302A Package Outline Dimensions (cont.) (All dimensions in mm.) DFN3x3-8 PAM8302A Document number: DSxxxxx Rev. 2 - 5 11 of 14 www.diodes.com April 2013 © Diodes Incorporated A Product Line of Diodes Incorporated PAM8302A Package Outline Dimensions (cont.) (All dimensions in mm.) SOP-8 PAM8302A Document number: DSxxxxx Rev. 2 - 5 12 of 14 www.diodes.com April 2013 © Diodes Incorporated A Product Line of Diodes Incorporated PAM8302A Package Outline Dimensions (cont.) (All dimensions in mm.) DFN2x2-8 PAM8302A Document number: DSxxxxx Rev. 2 - 5 13 of 14 www.diodes.com April 2013 © Diodes Incorporated A Product Line of Diodes Incorporated PAM8302A IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 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