A PRODUCT LINE OF DIODES INCORPORATED 2x3W Stereo Differential Input Class D Audio Amplifier with Up/Down Volume Control Description Pin Assignments The PAM8407 is a filter-less Class-D amplifier with high SNR and differential input that helps eliminate noise. Advanced 32-step Up/Down volume control minimizes external components and allows speaker volume control. SO-16 The PAM8407 supports 2.5V to 6V operation make it idea for up to 4 cells alkaline battery applications. RINP RINN SD UP DOWN GND LINN LINP Features like greater than 87% efficiency and small PCB area make the PAM8407 Class-D amplifier ideal for portable applications. The output uses a filter-less architecture minimizing the number of external components and PCB area whilst providing a high performance, simple and lower cost system. The PAM8407 built in auto recovery SCP (short circuit protection) and thermal shutdown. 16 VDD 15 ROUTP 14 ROUTN 13 GND 1 2 PAM8407 XX XY W WLL New Product PAM8407 3 4 5 6 7 12 GND 11 LOUTN 10 LOUTP 9 VDD 8 The PAM8407 is available in SO-16 package. Features Applications 3W Output at 10% THD with a 4Ω load and 5V Supply 2.4W Output at 1% THD with a 4Ω Load and 5V Supply 2.5V to 6.0V VDD Operating Fully Differential Input Filterless, Low Quiescent Current and Low EMI Low THD+N 32-stepUp/Down Volume Control from -80dB to 24dB Superior Low Noise: 60uV Minimize Pop/Clip Noise Auto Recovery Short Circuit Protection Thermal Shutdown Pb-Free SO-16 Package PC Speaker Wireless Speaker Home Sound Systems Active Speakers Docking stations Typical Applications Circuit RINP RINN C5 0. 1uF C6 0. 1uF ON SHDN 1 RINP VDD 16 2 RINN ROUTP 15 3 SD ROUTN 14 4 UP 5 DOWN 6 GND C7 LINN LINP 0. 1uF C8 0. 1uF PAM8407 Document number: DS36815 Rev. 1 - 2 7 LINN 8 LINP PAM8407 V DD C2 1uF 4Ω GND 13 GND 12 LOUTN 11 LOUTP 10 VDD 9 1 of 12 www.diodes.com 4Ω C2 1uF V DD January 2014 © Diodes Incorporated A PRODUCT LINE OF DIODES INCORPORATED 2x3W Stereo Differential Input Class D Audio Amplifier with Up/Down Volume Control PAM8407 New Product Pin Descriptions PIN Number PIN Name Description 1 RINP Positive Input of Right Channel Power Amplifier. 2 RINN Negative Input of Right Channel Power Amplifier. 3 SD Full Chip Shutdown Control Input (active low). 4 UP Volume UP Control (active low)Ground Connection. 5 DOWN 6,12,13 GND Ground. 7 LINN Negative Input of Left Channel Power Amplifier. 8 LINP Positive Input of Left Channel Power Amplifier. 9,16 VDD Power Supply. 10 LOUTP Positive Output of Left Channel Power Amplifier. 11 LOUTN Negative Output of Left Channel Power Amplifier. 14 ROUTN Negative Output of Right Channel Power Amplifier. 15 ROUTP Positive Output of Right Channel Power Amplifier. Volume down Control (active low) Functional Block Diagram GN D V DD R IN P + R IN N - R OU T N VD D DO WN Thermal Protection A tte n u a ti o n D e c o d e r VD D I n t e rf a c e C o n t r o l UP R OU T P DRIVER MODULATOR INTERNAL OSCILLATOR VD D BIAS AND REFERENCES SD OSC Current Protection LIN N + LIN P - MODULAT OR LOU T N D R IVER LOU T P VDD GND Absolute Maximum Ratings (@TA = +25°C, unless otherwise specified.) Parameter Rating Unit Supply Voltage (VDD) 6.5 Pins Input Voltage (SD, UP, Down, IN) -0.3 to VDD+0.3 V Storage Temperature -65 to +150 °C V Maximum Junction Temperature +150 Junction to ambient thermal resistance 40 PAM8407 Document number: DS36815 Rev. 1 - 2 °C °C/W 2 of 12 www.diodes.com January 2014 © Diodes Incorporated A PRODUCT LINE OF DIODES INCORPORATED 2x3W Stereo Differential Input Class D Audio Amplifier with Up/Down Volume Control PAM8407 New Product Recommended Operating Conditions (@TA = +25°C, unless otherwise specified.) Symbol Parameter Min Max Unit VDD Supply Voltage 2.5 6.0 V TA Operating Ambient Temperature Range -40 +85 °C TJ Junction Temperature Range -40 +125 °C Electrical Characteristics (@TA=25°C, VDD=5.0V, Gain=24dB, RL=8Ω (33μH)+R+L(33μH), unless otherwise noted.) PARAMETER Supply Voltage Range SYMBOL CONDITIONS MIN TYP MAX UNITS — 2.5 — 5.5 V IQ No Load — 8 — mA Output Offset Voltage VOS No Load — 10 — mV Drain-Source On-State Resistance P MOSFET — 0.3 — RDS(ON) N MOSFET — 0.2 — RL = 8Ω — 1.4 — RL = 4Ω — 2.4 — RL = 8Ω，PO = 0.85W, f = 1KHz — 0.08 — RL = 4Ω，PO = 1.75W, f = 1KHz — 0.08 — Input AC-GND, f = 1KHz, Vpp = 200mV — 70 — dB Quiescent Current Output Power VDD PO Total Harmonic Distortion Plus Noise THD+N Power Supply Ripple Rejection PSRR Ω IDS = 0.5A THD+N = 1%, f = 1kHz W % Channel Separation CS PO = 1W, f = 1KHz — -95 — dB Oscillator Frequency fOSC — 200 250 300 kHz PO = 1.1W,f = 1kHz, RL = 8Ω — 87 — % PO = 2.4W,f = 1kHz, RL = 4Ω — 83 — % A-weighting — 60 — No A-weighting — 80 — Efficiency Noise η Vn Input AC-GND μV Signal Noise Ratio SNR f = 20-20kHz, THD = 1% — 95 — dB Turn-on Time Ton VDD = 5V — 0.65 — S Mute Current IMUTE MUTE = VDD — 4 10 mA Shutdown Current ISD VSD = 0V — — 1 µA Logic Input High VIH Include SD, UP, DOWN 1.4 — — V Logic Input Low VIL Include SD, UP, DOWN — — 0.6 V Over Temperature Protection OTP — — 150 — °C Over Temperature Hysteresis OTH — — 40 — °C PAM8407 Document number: DS36815 Rev. 1 - 2 3 of 12 www.diodes.com January 2014 © Diodes Incorporated A PRODUCT LINE OF DIODES INCORPORATED 2x3W Stereo Differential Input Class D Audio Amplifier with Up/Down Volume Control PAM8407 Performance Characteristics (@TA = +25°C, VDD = 5V, Gain = 24dB, RL = L(33μH) + R + L(33μH), unless otherwise noted.) THD+N Vs. Output Power (RL=8Ω) THD+N Vs. Output Power (RL=4Ω) 20 10 5 40 20 f=100Hz/1kHz/10kHz (Red/Pink/Blue) 10 f=100Hz/1kHz/10kHz (Red/Pink/Blue) 5 New Product 2 2 1 1 0.5 % % 0.5 0.2 0.2 0.1 0.1 0.05 0.05 0.02 0.01 1m 0.02 2m 5m 10m 20m 50m 100m 200m 500m 1 0.01 1m 2 2m 5m 10m 20m 50m 100m W THD+N Vs. Frequency (RL=8Ω) 500m 1 2 THD+N Vs. Frequency (RL=4Ω) 10 10 5 2 200m W 5 PO=0.3W/0.5W/1W (Red/Pink/Blue) PO=0.5W/1W/2W (Red/Pink/Blue) 2 1 1 0.5 0.5 % % 0.2 0.2 0.1 0.1 0.05 0.05 0.02 0.02 0.008 20 50 100 200 500 1k 2k 5k 10k 0.01 20 20k 50 100 200 500 1k 2k 5k 10k 20k Hz Hz PSRR Vs. Frequency Crosstalk Vs Frequency +0 +0 -5 -10 -10 T -20 -15 -30 -20 -40 -25 -50 -30 -60 -35 d B d B -40 -45 -70 -80 -50 L to R -90 -55 -100 -60 -110 -65 -70 -120 -75 -130 -80 20 50 100 200 500 1k 2k 5k 10k 20k Hz PAM8407 Document number: DS36815 Rev. 1 - 2 -140 20 R to L 50 100 200 500 1k 2k 5k 10k 20k Hz 4 of 12 www.diodes.com January 2014 © Diodes Incorporated A PRODUCT LINE OF DIODES INCORPORATED 2x3W Stereo Differential Input Class D Audio Amplifier with Up/Down Volume Control PAM8407 Performance Characteristics (@TA = +25°C, VDD = 5V, Gain = 24dB, RL = L(33μH) + R + L(33μH), unless otherwise noted.) Frequency Response Noise Floor +16 +0 Cin=0.47uF +14 -10 Cin=1uF -20 -30 +12 d B g -50 Cin=0.1uF +8 A d B r -60 A -80 -70 +6 -90 -100 +4 -110 -120 +2 -130 +0 20 50 100 200 500 1k 2k 5k 10k -140 20 20k 50 100 200 Efficiency Vs. Output Power (RL=8Ω) 1k 2k 5k 10k 20k Efficiency Vs. Output Power (RL=4Ω) 100 80 80 60 60 Efficiency(%) 100 Efficiency(%) 500 Hz Hz 40 40 20 20 VDD=5V 0 VDD=5V 0 0 200 400 600 800 10001200140016001800 Output Power(mW) Output Power Vs. Supply Voltage (RL=8Ω, THD=10%) 0 2000 3000 Output Power(mW) 4000 1500 1000 Output Power(mW) 2000 3000 4000 Output Power Vs. Supply Voltage(RL=4Ω,THD=10%) 2500 Output Power(mW) New Product -40 +10 2000 1000 1000 500 0 0 2 3 4 5 Input Voltage(V) PAM8407 Document number: DS36815 Rev. 1 - 2 6 5 of 12 www.diodes.com 2 3 4 5 Input Voltage(V) 6 January 2014 © Diodes Incorporated A PRODUCT LINE OF DIODES INCORPORATED 2x3W Stereo Differential Input Class D Audio Amplifier with Up/Down Volume Control PAM8407 Performance Characteristics (@TA = +25°C, VDD = 5V, Gain = 24dB, RL = L(33μH) + R + L(33μH), unless otherwise noted.) OSC Frequency Vs. Supply Voltage 10 9 8 7 6 5 4 3 270 Quiescent Current(mA) 265 Frequency(kHz) 2 260 255 250 245 3 4 5 Supply Voltage(V) 240 6 2 3 Rdson Vs. Output Current 400 350 300 250 200 150 100 50 0 Rdson(mohm) New Product Quiescent Current Vs. Supply Voltage NMOS 0 PMOS STEP Gain STEP Gain 1 24 12 7.5 2 22.5 13 3 21 14 STEP 23 -10 Gain 6 24 -12 4.5 25 -14 -16 4 19.5 15 3 26 5 18 16 1.5 27 -18 6 16.5 17 0 28 -20 -22 7 15 18 -1.5 29 8 13.5 19 -3 30 -24 9 12* 20 -4.5 31 -26 21 -6 32 -80 22 -8 - - 10 10.36 11 9 *Default Gain=12dB Document number: DS36815 Rev. 1 - 2 6 Up/Down Volume Control (dB) 500 Output Current(mA) 1000 1500 PAM8407 4 5 Supply Voltage(V) 6 of 12 www.diodes.com January 2014 © Diodes Incorporated A PRODUCT LINE OF DIODES INCORPORATED 2x3W Stereo Differential Input Class D Audio Amplifier with Up/Down Volume Control PAM8407 Application Information Maximum Gain As shown in block diagram, the PAM8407 has two internal amplifiers stage. The first stage's gain is externally con-figurable, while the second stage's is internally fixed in a fixed-gain, inverting configuration. The closed-loop 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. Consequently, the differential gain for the IC is New Product AVD = 20*log [2*(Rf/Ri)] The PAM8407 sets maximum Rf=218kΩ and minimum Ri=27kΩ, thus the maximum closed-gain is 24dB. UP/DOWN Volume Control (DVC) The PAM8407 features a UP/DOWN volume control which consists of the UP and DOWN pins. An internal clock is used where the clock frequency value is determined from the following formula: 13 fCLK = fOSC / 2 The oscillator frequency fOSC value is 250kHz typical,with ±20% tolerance. The DVC’s clock frequency is 30Hz (cycle time 33ms) typical. Volume changes are then effected by toggling either the UP or DOWN pins with a logic low. After a period of 1 cycle pulses with either the UP or DOWN pins held low, the volume will change to the next specified step, either UP or DOWN, and followed by a short delay. This delay decreases the longer the line is held low, eventually reaching a delay of zero. The delay allows the user to pull the UP or DOWN terminal low once for one volume change, or hold down to ramp several volume changes. The delay is optimally configured for push button volume control. If either the UP or DOWN pin remains low after the first volume transition the volume will change again, but this time after 10 cycles. The followed transition occurs at 4 cycles for each volume transition. This is intended to provide the user with a volume control that pauses briefly after initial application, and then slowly increases the rate of volume change as it is continuously applied. This cycle is shown in the timing diagram shown in figure 1. There are 32 discrete gain settings ranging from +24dB maximum to -80dB minimum. Upon device power on or applied a logic low to the SD pin, the amplifier's gain is set to a default value of 12dB. Volume levels for each step vary and are specified in Gain Setting table on page 7. If both the UP and DOWN pins are held high, no volume change will occur. Trigger points for the UP and DOWN pins are at 70% of VDD minimum for a logic high, and 20% of VDD maximum for a logic low. It is recommended, however, to toggle UP and DOWN between VDD and GND for best performance. U P/D N VOL U ME L EVEL 1 c y c le 4 c y c le s 1 0 c y c le s 4 c y c le s Figure 1.Timming Diagram Shutdown operation In order to reduce power consumption while not in use, the PAM8407 contains shutdown circuitry that is used to turn off the amplifier's bias circuitry. This shutdown feature turns the amplifier off when logic low is placed on the SD pin. By switching the SD pin connected to GND, the PAM8407 supply current draw will be minimized in idle mode. The SD pin cannot be left floating due to the pull-down internal. PAM8407 Document number: DS36815 Rev. 1 - 2 7 of 12 www.diodes.com January 2014 © Diodes Incorporated A PRODUCT LINE OF DIODES INCORPORATED 2x3W Stereo Differential Input Class D Audio Amplifier with Up/Down Volume Control PAM8407 Application Information (Continued) Power supply decoupling New Product The PAM8407 is a high performance CMOS audio amplifier that requires adequate power supply decoupling to ensure the output THD and PSRR are as low as possible. Power supply decoupling is affecting 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, typically 1.0µF, placed as close as possible to the device VDD terminal works best. For filtering lower-frequency noise signals, a larger capacitor of 10µF (ceramic) or greater placed near the audio power amplifier is recommended. Input Capacitor (Ci) Large input capacitors are both expensive and space hungry for portable designs. Clearly, a certain sized capacitor is needed to couple in low frequencies without severe attenu-ation. But in many cases the speakers used in portable systems, whether internal or external, have little ability to reproduce signals below 100Hz to 150Hz. Thus, using a large input capacitor may not increase actual system perfor-mance. In this case, input capacitor (Ci) and input resistance (Ri) of the amplifier form a high-pass filter with the corner frequency determined equation below, fC= 1 2πRiCi In addition to system cost and size, click and pop perfor-mance is affected by the size of the input coupling capacitor, Ci. A larger input coupling capacitor requires more charge to reach its quiescent DC voltage (nominally 1/2 VDD). This charge comes from the internal circuit via the feedback and is apt to create pops upon device enable. Thus, by minimizing the capacitor size based on necessary low frequency response, turnon pops can be minimized. Under Voltage Lock-out (UVLO) The PAM8407 incorporates circuitry designed to detect when the supply voltage is low. When the supply voltage drops to 2.4V or below, the PAM8407 outputs are disable, and the device comes out of this state and starts to normal functional when the supply voltage increases. Short Circuit Protection (SCP) The PAM8407 has short circuit protection circuitry on the outputs that prevents damage to the device during output-to-output and output-to-GND short. When a short circuit is detected on the outputs, the outputs are disable immediately. If the short was removed, the device activates again. Over Temperature Protection Thermal protection on the PAM8407 prevents damage to the device when the internal die temperature exceeds 150°C. There is a 15 degree tolerance on this trip point from device to device. Once the die temperature exceeds the thermal set point, the device outputs are disabled. This is not a latched fault. The thermal fault is cleared once the temperature of the die is reduced by 60°C. This large hysteresis will prevent motor boating sound well and the device begins normal operation at this point with no external system interaction. How to Reduce EMI (Electro Magnetic Interference) A simple solution is to put an additional capacitor 1000uF 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 which shows at Figure 3. The ferrite filter reduces EMI around 1 MHz and higher. When selecting a ferrite bead, choose one with high impedance at high frequencies, but low impedance at low frequencies. PAM8407 Document number: DS36815 Rev. 1 - 2 8 of 12 www.diodes.com January 2014 © Diodes Incorporated A PRODUCT LINE OF DIODES INCORPORATED 2x3W Stereo Differential Input Class D Audio Amplifier with Up/Down Volume Control PAM8407 Application Information (Continued) Ferrite Bead OUT+ New Product 220pF Ferrite Bead OUT220pF Figure 3: Ferrite Bead Filter to reduce EMI PCB Layout Guidelines Grounding At this stage it is paramount that we acknowledge the need for separate grounds. Noise currents in the output power stage need to be returned to output noise ground and nowhere else. Were these currents to circulate elsewhere, they may get into the power supply, the signal ground, etc, worse yet, they may form a loop and radiate noise. Any of these instances results in degraded amplifier performance. The logical returns for the output noise currents associated with Class D switching are the respective PGND pins for each channel. The switch state diagram illustrates that PGND is instrumental in nearly every switch state. This is the perfect point to which the output noise ground trace should return. Also note that output noise ground is channel specific. A two channels amplifier has two mutually exclusive channels and consequently must have two mutually exclusive output noise ground traces. The layout of the PAM8407 offers separate PGND connections for each channel and in some cases each side of the bridge. Output noise grounds must tie to system ground at the power in exclusively. Signal currents for the inputs, reference, etc need to be returned to quite ground. This ground only ties to the signal components and the GND pin. GND then ties to system ground. Power Supply Line As same to the ground, VDD and each channel PVDD need to be separated and tied together at the system power supply. Recommend that all the trace could be routed as short and thick as possible. For the power line layout, just imagine water stream, any barricade placed in the trace (shows in figure 4) could result in the bad performance of the amplifier. Figure 4 Components Placement The power supply decoupling capacitors need to be placed as close to VDD pins as possible. The inputs need to be routed away from the noisy trace. PAM8407 Document number: DS36815 Rev. 1 - 2 9 of 12 www.diodes.com January 2014 © Diodes Incorporated A PRODUCT LINE OF DIODES INCORPORATED 2x3W Stereo Differential Input Class D Audio Amplifier with Up/Down Volume Control PAM8407 Ordering Information PAM8407 X X New Product Package Type Shipping Package D: SO-16 R: Tape & Real Part Number Package Standard Package PAM8407DR SO-16 2,500Units/Tape&Real Marking Information PAM8407 Document number: DS36815 Rev. 1 - 2 1 2 3 4 5 6 7 8 PAM8407 XX XY W WLL RINP RINN SD UP DOWN GND LINN LINP 16 VDD 15 ROUTP 14 ROUTN 13 GND 12 GND 11 LOUTN 10 LOUTP 9 VDD 10 of 12 www.diodes.com PAM8407: Product Code X: Internal Code Y: Year W: Week LL: Internal Code January 2014 © Diodes Incorporated A PRODUCT LINE OF DIODES INCORPORATED 2x3W Stereo Differential Input Class D Audio Amplifier with Up/Down Volume Control PAM8407 Package Outline Dimensions (All dimensions in mm.) Please see AP02002 at http://www.diodes.com/datasheets/ap02002.pdf for latest version. New Product Package: SO-16 H E SO-16 Dim Min Max A 1.40 1.75 A1 0.10 0.25 A2 1.30 1.50 B 0.33 0.51 C 0.19 0.25 D 9.80 10.00 E 3.80 4.00 e 1.27 Typ H 5.80 6.20 L 0.38 1.27 0 8 All Dimensions in mm Gauge Plane L Detail ‘A’ D A A2 e B A1 C Detail ‘A’ Suggested Pad Layout (All dimensions in mm.) Please see AP02001 at http://www.diodes.com/datasheets/ap02001.pdf for the latest version. X1 Dimensions C X X1 Y Y1 Y1 Value (in mm) 1.270 0.670 9.560 1.450 6.400 Y Pin 1 X PAM8407 Document number: DS36815 Rev. 1 - 2 C 11 of 12 www.diodes.com January 2014 © Diodes Incorporated A PRODUCT LINE OF DIODES INCORPORATED 2x3W Stereo Differential Input Class D Audio Amplifier with Up/Down Volume Control PAM8407 IMPORTANT NOTICE New Product 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). Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein. 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