IRAUDAMP8 120W x 4 Channel Class D Audio Power Amplifier Using the IRS2093M and IRF6665 By Jun Honda, Yasushi Nishimura and Liwei Zheng CAUTION: International Rectifier suggests the following guidelines for safe operation and handling of IRAUDAMP8 Demo board; Always wear safety glasses whenever operating Demo Board Avoid personal contact with exposed metal surfaces when operating Demo Board Turn off Demo Board when placing or removing measurement probes www.irf.com IRAUDAMP8 REV 1.0 Page 1 of 34 TABLE OF CONTENTS PAGE INTRODUCTION............................................................................................................................................... 3 SPECIFICATIONS ............................................................................................................................................ 3 CONNECTION SETUP ..................................................................................................................................... 5 CONNECTOR DESCRIPTION ......................................................................................................................... 5 TEST PROCEDURES....................................................................................................................................... 6 PERFORMANCE AND TEST GRAPHS .......................................................................................................... 7 CLIPPING CHARACTERISTICS.................................................................................................................... 10 EFFICIENCY................................................................................................................................................... 11 THERMAL CONSIDERATIONS ..................................................................................................................... 11 THERMAL INTERFACE MATERIAL’S PRESSURE CONTROL ................................................................................. 12 POWER SUPPLY REJECTION RATIO (PSRR)............................................................................................ 14 SHORT CIRCUIT PROTECTION RESPONSE .............................................................................................. 15 IRAUDAMP8 OVERVIEW .............................................................................................................................. 16 FUNCTIONAL DESCRIPTIONS..................................................................................................................... 18 IRS2093 GATE DRIVER IC ............................................................................................................................ 18 SELF-OSCILLATING FREQUENCY .................................................................................................................... 19 ADJUSTMENTS OF SELF-OSCILLATING FREQUENCY ......................................................................................... 19 SELECTABLE DEAD-TIME ................................................................................................................................ 20 PROTECTION SYSTEM OVERVIEW ............................................................................................................ 21 CLICK AND POP NOISE REDUCTION ......................................................................................................... 23 BUS PUMPING............................................................................................................................................... 23 INPUT SIGNAL AND GAIN SETTING ........................................................................................................... 25 GAIN SETTING............................................................................................................................................... 25 SCHEMATIC…………………………………………………………………………………………………………. .26 IRAUDAMP8 FABRICATION MATERIALS................................................................................................... 27 IRAUDAMP8 HARDWARE ............................................................................................................................ 30 IRAUDAMP8 PCB SPECIFICATIONS........................................................................................................... 31 REVISION CHANGES DESCRIPTIONS........................................................................................................ 34 www.irf.com IRAUDAMP8 REV 1.0 Page 2 of 34 Introduction The IRAUDAMP8 Demo board is a reference design which uses only one IC (IRS2093M) to derive appropriate input signals, amplify the audio input, and achieve a four-channel 120 W/ch (4Ω) half-bridge Class D audio power amplifier. The reference design demonstrates how to use the IRS2093M Class D audio controller and gate driver IC, implement protection circuits, and design an optimum PCB layout using IRF6665 DirectFET MOSFETs. The reference design contains all the required housekeeping power supplies for ease of use. The four-channel design is scalable, for power and number of channels. Applications AV receivers Home theater systems Mini component stereos Powered speakers Sub-woofers Musical Instrument amplifiers Automotive after market amplifiers Features Output Power: Residual Noise: Distortion: Efficiency: Multiple Protection Features: PWM Modulator: 120W x 4 channels, 200V, IHF-A weighted, AES-17 filter 0.012% THD+N @ 60W, 4Ω 90% @ 120W, 4Ω, single-channel driven, Class D stage Over-current protection (OCP), high side and low side Over-voltage protection (OVP), Under-voltage protection (UVP), high side and low side Over-temperature protection (OTP) Self-oscillating half-bridge topology with optional clock synchronization Specifications General Test Conditions (unless otherwise noted) Supply Voltages ±35V Load Impedance 4Ω Self-Oscillating Frequency 400kHz Gain Setting 26.5dB Notes / Conditions No input signal, Adjustable 1Vrms input yields rated power Electrical Data IR Devices Used Typical Notes / Conditions IRS2093M Audio Controller and Gate-Driver, IRF6665 DirectFET MOSFETs Modulator Self-oscillating, second order sigma-delta modulation, analog input Power Supply Range ± 25V to ±35V Bipolar power supply Output Power CH1-4: (1% THD+N) 120W 1kHz Output Power CH1-4: (10% THD+N) 170W 1kHz Rated Load Impedance 8-4Ω Resistive load www.irf.com IRAUDAMP8 REV 1.0 Page 3 of 34 Standby Supply Current Total Idle Power Consumption Channel Efficiency ±100mA 7W 90% No input signal No input signal Single-channel driven, 120W, Class D stage . Audio Performance *Before Demodula tor Class D Output THD+N, 1W THD+N, 10W THD+N, 60W THD+N, 100W 0.015% 0.006% 0.005% 0.015% 0.015% 0.008% 0.012% 0.02% Dynamic Range 101dB 101dB Residual Noise, 22Hz - 20kHzAES17 200V 200V Damping Factor Channel Separation 2000 85dB 85dB 75dB N/A 48 78dB 77dB 70dB ±1dB ±3dB Frequency Response : 20Hz-20kHz : 20Hz-35kHz Thermal Performance Idling 4ch x 15W (1/8 rated power) 4ch x 120W (Rated power) Physical Specifications Dimensions Typical TC =30C TPCB=42C TC =54C TPCB=71C TC =80C TPCB=106C Notes / Conditions 1kHz, Single-channel driven A-weighted, AES-17 filter, Single-channel operation Self-oscillating – 400kHz 1kHz, relative to 4Ω load 100Hz 1kHz 10kHz 1W, 4Ω - 8Ω Load Notes / Conditions No signal input, TA=25C Continuous, TA=25C At OTP shutdown @ 150 sec, TA=25C Weight 3.94”(L) x 2.83”(W) x 0.85”(H) 100 mm (L) x 72 mm (W) x 21.5 mm(H) 0.140kgm www.irf.com IRAUDAMP8 REV 1.0 Page 4 of 34 Connection Setup Audio Signal Generator CH1 CH2 CH3 CH4 Input Frequency adjustor VR1 DS1 ,VCC INDICATOR IRS2093 IRF6665 Output Output CH2 CH1 +B GND -B CH4 CH3 G 35 V, 10 A DC supply 250W,4ΩNon-inductive 35 V, 10 A DC supply Fig 1 Typical Test Setup Connector Description CH1 IN CH2 IN CH3 IN CH4 IN SUPPLY CH1 OUT CH2 OUT CH3 OUT CH4 OUT www.irf.com CN1 CN1 CN1 CN1 P1 P2 P2 P3 P3 Analog input for CH1 Analog input for CH2 Analog input for CH3 Analog input for CH4 Positive and negative supply (+B / -B) Output for CH1 Output for CH2 Output for CH3 Output for CH4 IRAUDAMP8 REV 1.0 Page 5 of 34 Test Procedures Test Setup: 1. Connect 4-200 W dummy loads to 4 output connectors (P2 and P3 as shown on Fig 1) and an Audio Precision analyzer (AP). 2. Connect the Audio Signal Generator to CN2 for CH1~CH4 respectively (AP). 3. Set up the dual power supply with voltages of ±35V; current limit to 10A. 4. TURN OFF the dual power supply before connecting to On of the unit under test (UUT). 5. Connect the dual power supply to P1. as shown on Fig 1 Power up: 6. Turn ON the dual power supply. The ±B supplies must be applied and removed at the same time. 7. The Blue LED should turn ON immediately and stay ON 8. Quiescent current for the positive supply should be 100mA 10mA at +35V. 9. Quiescent current for the negative supply should be 115mA 10mA at –35V. Switching Frequency test 10. With an Oscilloscope, monitor the switching waveform at test points VS1~VS4. Adjust VR1 to set the self oscillating frequency to 400 kHz 25 kHz. Functionality Audio Tests: 11. Set the signal generator to 1kHz, 20 mVRMS output. 12. Connect the audio signal generator to CN2(Input of CH1,CH2,CH3,CH4) 13. Sweep the audio signal voltage from 15 mVRMS to 1 VRMS. 14. Monitor the output signals at P2/P3 with an oscilloscope. The waveform must be a non distorted sinusoidal signal. 15. Observe that a 1 VRMS input generates an output voltage of 21.2 VRMS. The ratio, R4A/(R3A), determines the voltage gain of IRAUDAMP8. Test Setup using Audio Precision (Ap): 16. Use an unbalanced-floating signal from the generator outputs. 17. Use balanced inputs taken across output terminals, P2 and P3. 18. Connect Ap frame ground to GND at terminal P1. 19. Select the AES-17 filter(pull-down menu) for all the testing except frequency response. 20. Use a signal voltage sweep range from 15 mVRMS to 1 VRMS. 21. Run Ap test programs for all subsequent tests as shown in Fig 2- Fig 7below. www.irf.com IRAUDAMP8 REV 1.0 Page 6 of 34 Performance and test graphs 10 5 2 1 0.5 0.2 % 0.1 0.05 0.02 0.01 0.005 0.002 0.001 100m 200m 500m 1 2 5 10 20 50 100 200 W CH1-Blue; CH2-Yellow; CH3-Red; CH4-Cyan ±B Supply = ±35V, 4 Ω Resistive Load Fig 2 IRAUDAMP8, THD+N versus Power, Stereo, 4 Ω . +4 T +3 +2 +1 -0 -1 d B r -2 A -4 -3 -5 -6 -7 -8 -9 -10 20 50 100 200 500 1k 2k 5k 10k 20k 50k 100k 200k Hz CH1-Blue; CH2-Yellow; CH3-Red; CH4-Cyan ±B Supply = ±35V, 4 Ω Resistive Load Fig 3 IRAUDAMP8, Frequency response www.irf.com IRAUDAMP8 REV 1.0 Page 7 of 34 100 50 20 10 5 2 1 0.5 % 0.2 0.1 0.05 0.02 0.01 0.005 0.002 0.001 0.0005 0.0002 0.0001 20 50 100 200 500 1k 2k 5k 10k 20k Hz Red Blue CH1, 10W Output CH1, 50W Output Fig 4 THD+N Ratio vs. Frequency CH1-Blue; CH2-Yellow; CH3-Red; CH4-Cyan Fig 5, 1V output Frequency Spectrum www.irf.com IRAUDAMP8 REV 1.0 Page 8 of 34 CH1-Blue; CH2-Yellow; CH3-Red; CH4-Cyan No signal, Self Oscillator @ 400kHz Fig 6, IRAUDAMP8 Noise Floor . +0 -10 -20 -30 -40 -50 d B -60 -70 -80 -90 -100 -110 -120 20 50 100 200 500 1k 2k 5k 10k 20k Hz Red Blue CH1 – CH2, 60W CH2 – CH1, 60W Fig 7, Channel separation vs. frequency www.irf.com IRAUDAMP8 REV 1.0 Page 9 of 34 Clipping characteristics Red Trace: Total Distortion + Noise Voltage Green Trace: Output Voltage 60W / 4, 1kHz, THD+N=0.012% 174W / 4, 1kHz, THD+N=10% Measured Output and Distortion Waveforms Fig 8 Clipping Characteristics . www.irf.com IRAUDAMP8 REV 1.0 Page 10 of 34 Efficiency Fig 9 shows efficiency characteristics of the IRAUDAMP8. The high efficiency is achieved by following major factors: 1) Low conduction loss due to the DirectFETs offering low RDS(ON) 2) Low switching loss due to the DirectFETs offering low input capacitance for fast rise and fall times Secure dead-time provided by the IRS2093, avoiding cross-conduction 100% 90% Efficiency (%) 80% 70% 60% AMP8 35V 4ohms 50% 40% 30% 20% 10% 0% 0 50 100 150 Output power (W) Fig 9, IRAUDAMP8 4 ohms load Stereo, ±B supply = ±35V Thermal Considerations With this high efficiency, the IRAUDAMP8 design can handle one-eighth of the continuous rated power, which is generally considered to be a normal operating condition for safety standards, without additional heatsinks or forced air-cooling. www.irf.com IRAUDAMP8 REV 1.0 Page 11 of 34 Thermal Interface Material’s Pressure Control The pressure between DirectFET & TIM (Thermal Interface Material) is controlled by depth of Heat Spreader’s groove. Choose TIM which is recommended by IR. (Refer to AN-1035 for more details). TIM’s manufacturer thickness, conductivity, & etc. determine pressure requirement. Below shows selection options recommended: Fig 10 TIM Information www.irf.com IRAUDAMP8 REV 1.0 Page 12 of 34 Check the TIM’s compression deflection with constant rate of strain (example as Fig.11) base on manufacturer’s datasheet. According to the stress requirement, find strain range for the TIM. Then, calculate heat spreader groove depth as below: Groove Depth=DirectFET’s Height +TIM’s Thickness*strain **DirectFET’s height should be measured from PCB to the top of DirectFET after reflow. The average height of IRF6665 is 0.6mm. Fig 11 compression deflection with constant rate of strain www.irf.com IRAUDAMP8 REV 1.0 Page 13 of 34 Power Supply Rejection Ratio (PSRR) The IRAUDAMP8 obtains good power supply rejection ratio of -68 dB at 1kHz shown in Fig 12. With this high PSRR, IRAUDAMP8 accepts any power supply topology when the supply voltages fit between the min and max range. +0 -10 -20 -30 d B V -40 -50 -60 -70 -80 -90 20 50 100 200 500 1k 2k 5k 10k 20k 40k Hz Sweep Trace Color Line Style Thick Data Axis 1 1 Red Solid 2 Anlr.Ampl Left Comment Fig 12 Amp8 Power Supply Rejection Ratio (PSRR) www.irf.com IRAUDAMP8 REV 1.0 Page 14 of 34 Short Circuit Protection Response Figs 13-14 show over current protection reaction time of the IRAUDAMP8 in a short circuit event. As soon as the IRS2093 detects an over current condition, it shuts down PWM. After one second, the IRS2093 tries to resume the PWM. If the short circuit persists, the IRS2093 repeats try and fail sequences until the short circuit is removed. Short Circuit in Positive and Negative Load Current CSD pin CSD pin VS pin VS pin Load current Load current Positive OCP Negative OCP Fig 13 Positive and Negative OCP Waveforms . OCP Waveforms Showing CSD Trip and Hiccup CSD pin CSD pin VS pin VS pin Load current Load current Fig 14 OCP Response with Continuous Short Circuit www.irf.com IRAUDAMP8 REV 1.0 Page 15 of 34 IRAUDAMP8 Overview The IRAUDAMP8 features a 4CH self-oscillating type PWM modulator for the smallest space, highest performance and robust design. This topology represents an analog version of a secondorder sigma-delta modulation having a Class D switching stage inside the loop. The benefit of the sigma-delta modulation, in comparison to the carrier-signal based modulation, is that all the error in the audible frequency range is shifted to the inaudible upper-frequency range by nature of its operation. Also, sigma-delta modulation allows a designer to apply a sufficient amount of error correction. The IRAUDAMP8 self-oscillating topology consists of following essential functional blocks. Front-end integrator PWM comparator Level shifters Gate drivers and MOSFETs Output LPF Integrator Referring to Fig 15 below, the input operational amplifier of the IRS2093 forms a front-end secondorder integrator with R3, C2, C3, and R2. The integrator that receives a rectangular feedback signal from the PWM output via R4 and audio input signal via R3 generates a quadratic carrier signal at the COMP pin. The analog input signal shifts the average value of the quadratic waveform such that the duty cycle varies according to the instantaneous voltage of the analog input signal. PWM Comparator The carrier signal at the COMP pin is converted to a PWM signal by an internal comparator that has a threshold at middle point between VAA and VSS. The comparator has no hysteresis in its input threshold. Level Shifters The internal input level-shifter transfers the PWM signal down to the low-side gate driver section. The gate driver section has another level-shifter that level shifts up the high-side gate signal to the high-side gate driver section. www.irf.com IRAUDAMP8 REV 1.0 Page 16 of 34 Gate Drivers and DirectFETs The received PWM signal is sent to the dead-time generation block where a programmable amount of dead time is added into the PWM signal between the two gate output signals of LO and HO to prevent potential cross conduction across the output power DirectFETs. The high-side levelshifter shifts up the high-side gate drive signal out of the dead-time block. Each channel of the IRS2093’s drives two DirectFETs, high- and low-sides, in the power stage providing the amplified PWM waveform. Output LPF The amplified PWM output is reconstructed back to an analog signal by the output LC LPF. Demodulation LC low-pass filter (LPF) formed by L1 and C13, filters out the Class D switching carrier signal leaving the audio output at the speaker load. A single stage output filter can be used with switching frequencies of 400 kHz and greater; a design with a lower switching frequency may require an additional stage of LPF. Fig 15 Simplified Block Diagram of IRAUDAMP8 Class D Amplifier www.irf.com IRAUDAMP8 REV 1.0 Page 17 of 34 Functional Descriptions IRS2093 Gate Driver IC The IRAUDAMP8 uses the IRS2093, a 4 Channel high-voltage (up to 200 V), high-speed power MOSFET driver with internal dead-time and protection functions specifically designed for Class D audio amplifier applications. These functions include OCP and UVP. The IRS2093 integrates bidirectional over current protection for both high-side and low-side MOSFETs. The dead-time can be selected for optimized performance according to the size of the MOSFET, minimizing deadtime while preventing shoot-through. As a result, there is no gate-timing adjustment required externally. Selectable dead-time through the DT pin voltage is an easy and reliable function which requires only two external resistors, R12 and R13 as shown on Fig 16 or Fig 22 below. The IRS2093 offers the following functions. PWM modulator Dead-time insertion Over current protection Under voltage protection Level shifters Refer to IRS2093 datasheet and AN-1146 for more details. Fig 16 System-level View of IRAUDAMP8 www.irf.com IRAUDAMP8 REV 1.0 Page 18 of 34 Self-Oscillating Frequency Self-oscillating frequency is determined by the total delay time along the control loop of the system; the propagation delay of the IRS2093, the DirectFETs switching speed, the time-constant of front-end integrator (R2, R3, R4, C2, C3 ). Variations in +B and –B supply voltages also affect the self-oscillating frequency. The self-oscillating frequency changes with the duty ratio. The frequency is highest at idling. It drops as duty cycle varies away from 50%. Adjustments of Self-Oscillating Frequency Use R2 to set different self-oscillating frequencies. The PWM switching frequency in this type of self-oscillating switching scheme greatly impacts the audio performance, both in absolute frequency and frequency relative to the other channels. In absolute terms, at higher frequencies, distortion due to switching-time becomes significant, while at lower frequencies, the bandwidth of the amplifier suffers. In relative terms, interference between channels is most significant if the relative frequency difference is within the audible range. Normally, when adjusting the self-oscillating frequency of the different channels, it is suggested to either match the frequencies accurately, or have them separated by at least 25kHz. Under the normal operating condition with no audio input signal, the switching-frequency is set around 400kHz in the IRAUDAMP8. www.irf.com IRAUDAMP8 REV 1.0 Page 19 of 34 Selectable Dead-time The dead-time of the IRS2093 is set based on the voltage applied to the DT pin. Fig 17 lists the suggested component value for each programmable dead-time between 45 and 105 ns. All the IRAUDAMP8 models use DT1 (45ns) dead-time. Dead-time Mode DT1 DT2 DT3 DT4 R1 <10k 5.6k 8.2k Open R2 Open 4.7k 3.3k <10k DT/SD Voltage Vcc 0.46 x Vcc 0.29 x Vcc COM Recommended Resistor Values for Dead Time Selection Dead- time IRS2093M 45nS >0.5mA Vcc 65nS R1 85nS DT 105nS R2 0.23xVcc 0.36xVcc 0.57xVcc Vcc VDT COM Fig 17 Dead-time Settings vs. VDT Voltage www.irf.com IRAUDAMP8 REV 1.0 Page 20 of 34 Protection System Overview The IRS2093 integrates over current protection (OCP) inside the IC. The rest of the protections, such as over-voltage protection (OVP), under-voltage protection (UVP), and over temperature protection (OTP), are detected externally to the IRS2093 (Fig 18). The external shutdown circuit will disable the output by pulling down CSD pins, (Fig 19). If the fault condition persists, the protection circuit stays in shutdown until the fault is removed. R60 15k SD GND Q5 MMBT5551 R54 10k Z4 18V R57 47k R56 47k R51 22k R50 47k Z3 39V R53 R59 22k Q3 MMBT5551 10k 5 4 IC6 LM26CIM5-XHA 1 OS HT 2 GND 3 VCC VT OTP R52 15k D51 4.7V Q4 MMBT5551 R58 47k R55 47k OVP UVP -B Fig 18 DCP, OTP, UVP and OVP Protection Circuits . Fig 19 Simplified Functional Diagram of OCP www.irf.com IRAUDAMP8 REV 1.0 Page 21 of 34 Over-Current Protection (OCP) Low-Side Current Sensing The low-side current sensing feature protects the low side DirectFET from an overload condition from negative load current by measuring drain-to-source voltage across RDS(ON) during its on state. OCP shuts down the switching operation if the drain-to-source voltage exceeds a preset trip level. The voltage setting on the OCSET pin programs the threshold for low-side over-current sensing. When the VS voltage becomes higher than the OCSET voltage during low-side conduction, the IRS2093 turns the outputs off and pulls CSD down to -VSS. High-Side Current Sensing The high-side current sensing protects the high side DirectFET from an overload condition from positive load current by measuring drain-to-source voltage across RDS(ON) during its on state. OCP shuts down the switching operation if the drain-to-source voltage exceeds a preset trip level. High-side over-current sensing monitors drain-to-source voltage of the high-side DirectFET during the on state through the CSH and VS pins. The CSH pin detects the drain voltage with reference to the VS pin, which is the source of the high-side DirectFET. In contrast to the low-side current sensing, the threshold of the CSH pin to trigger OC protection is internally fixed at 1.2V. An external resistive divider R15, R16 and R17 are used to program a threshold as shown in Fig 18. An external reverse blocking diode D1 is required to block high voltage feeding into the CSH pin during low-side conduction. By subtracting a forward voltage drop of 0.6V at D1, the minimum threshold which can be set for the high-side is 0.6V across the drain-to-source. Over-Voltage Protection (OVP) OVP is provided externally to the IRS2093. OVP shuts down the amplifier if the bus voltage between GND and -B exceeds 39V. The threshold is determined by a Zener diode Z3. OVP protects the board from harmful excessive supply voltages, such as due to bus pumping at very low frequency-continuous output in stereo mode. Under-Voltage Protection (UVP) UVP is provided externally to the IRS2093. UVP prevents unwanted audible noise output from unstable PWM operation during power up and down. UVP shuts down the amplifier if the bus voltage between GND and -B falls below a voltage set by Zener diode Z4. www.irf.com IRAUDAMP8 REV 1.0 Page 22 of 34 Offset Null (DC Offset) Adjustment The IRAUDAMP8 requires no output-offset adjustment. DC offsets are tested to be less than ±20 mV. Over-Temperature Protection (OTP) A Preset Thermostat IC, IC6 in Fig 17, is placed in close proximity to the heatsink which has 8 DirectFETs under it; and monitors heatsink temperature. If the heatsink temperature rises above 100 C, the OTP shuts down all 4 channels by pulling down the CSD pins of the IRS2093. OTP recovers once the temperature has cooled down. Click and POP Noise Reduction Thanks to the click and pop elimination function built into the IRS2093, the IRAUDAMP8 does not require any additional components for this function. Power Supply Requirements For convenience, the IRAUDAMP8 has all the necessary housekeeping power supplies onboard and only requires a pair of symmetric power supplies. Or you can use it with the IRAUDPS1 reference design which is a 12 volt systems Audio Power Supply for automotive applications designed to provide voltage rails (+B and –B) for Class D audio power amplifiers . House Keeping Power Supply The internally-generated housekeeping power supplies include ±5V for analog signal processing, and +12V supply (VCC) referred to the negative supply rail -B for DirectFET gate drive. The gate driver section of the IRS2093 uses VCC to drive gates of the DirectFETs. VCC is referenced to –B (negative power supply). D2, R18 and C10 form a bootstrap floating supply for the HO gate driver. Bus Pumping When the IRAUDAMP8 is running in stereo mode, the bus pumping effect takes place with low frequency, high output. Since the energy flowing in the Class D switching stage is bi-directional, there is a period where the Class D amplifier feeds energy back to the power supply. The majority of the energy flowing back to the supply is from the energy stored in the inductor in the output LPF. www.irf.com IRAUDAMP8 REV 1.0 Page 23 of 34 Usually, the power supply has no way to absorb the energy coming back from the load. Consequently the bus voltage is pumped up, creating bus voltage fluctuations. Following conditions make bus pumping worse: 1. Lower output frequencies (bus-pumping duration is longer per half cycle) 2. Higher power output voltage and/or lower load impedance (more energy transfers between supplies) 3. Smaller bus capacitance (the same energy will cause a larger voltage increase) The OVP protects IRAUDAMP8 from failure in case of excessive bus pumping. One of the easiest counter measures of bus pumping is to drive both of the channels in a stereo configuration out-ofphase so that one channel consumes the energy flow from the other and does not return it to the power supply. Bus voltage detection monitors only +B supply, assuming the bus pumping on the supplies is symmetric in +B and -B supplies. Blue: VS of CH3;Cyan: VS of CH2;Magenta: Voltage of +B;Green:Current of C13A Fig 20 Auto-phase sync clock’s BUS Pumping when idling www.irf.com IRAUDAMP8 REV 1.0 Page 24 of 34 Load Impedance Each channel is optimized for a 4 Ω speaker load in half bridge. Input Signal and Gain Setting A proper input signal is an analog signal ranging from 20Hz to 20kHz with up to 3 VRMS amplitude with a source impedance of no more than 600 Ω. Input signal with frequencies from 30kHz to 60kHz may cause LC resonance in the output LPF, causing a large reactive current flowing through the switching stage, especially with greater than 8 Ω load impedances, and the LC resonance can activate OCP. The IRAUDAMP8 has an RC network called a Zobel network (R21 and C14) to damp the resonance and prevent peaking frequency response with light loading impedance. (Fig 21) Fig 21 Output Low Pass Filter and Zobel Network Gain Setting The ratio of resistors R4A~D/R1A~D in Fig 22 sets voltage gain. The IRAUDAMP8 has no on board volume control. To change the voltage gain, change the input resistor term R1A~D. Changing R4A~D affects PWM control loop design and may result poor audio performance. www.irf.com IRAUDAMP8 REV 1.0 Page 25 of 34 Schematic 22uF, 16V R16C 3.9K SD 1R 4.7R D1C 1N4148 R60 15k +5v C1 Q5 MMBT5551 Q8 ZX5T853 R43 R51 22k 510R,1W R45 33k VR1 10K 1 2 3 VCC OUT GND SET DIT 5 4 2 3 4 1A VCC 1B 1Y 2Y 2B GND 2A 15k C41 N/A Z6 5.6V D51 4.7V R46 8 -5v ZX5T953 33k R44 510R,1W R54 10k 6 R57 47k R56 47k 5 5.1k Z4 18V Z3 39V R53 Q3 MMBT5551 DS1 R58 47k R55 47k OVP L5 R37 47k R42 3.3k R32 1k Q1 220uH C35 2200pF,50V R31 5.1k Q4 MMBT5551 0.01uF, 50V 1 C34 2 0.01uF, 25V R41 120k C36 0.01uF, 50V 3 4 D7 R40 100k SW VIN BST VCC RCL RON/SD RTN FB 0.01uF, 50V R62 10k GND For EMI Fig 22 IRAUDAMP8 Schematic IRAUDAMP8 REV 1.0 Page 26 of 34 8 7 Q2 R39 100k 6 MMBT5401 FX491 5 C32 2.2uF, 50V LM5007 UVP 10k R61 C62 www.irf.com 15V IC9 VCC R50 47k 10k GND Z2 R36 7 IC8 TC7W00FFCT-ND C61 OS R52 Q9 1 IC6 LM26CIM5-XHA 1 HT 2 GND 3 VCC VT 5 4 R59 22k Z5 5.6V C40 N/A IC2 LTC1799 C37 22uF, 16V R3 22k C14A R21A 0.1uF, 63V 10R,1W 0.1uF, 63V R21D 10R,1W R21B 0.1uF, 63V 10R,1W C14B C14C R21C 10R,1W 0.1uF, 63V 0.47uF, 400V C13A C14D 0.47uF, 400V C13B C17D 0.1uF,50V 22R R18C R23A 100k C17A 1000uF,35V P1 GND 0.1uF,100V C19C 1R C17C 0.1uF,50V R22C 10K 0.1uF,50V 0.47uF, 400V C13D 1R 1R R19B C19B 0.1uF,100V C19A R19A 0.1uF,100V R22D 10K 22R Q2D IRF6665 R19C R19D Q1D IRF6665 R20D R9D 10K +B 22R 0.1uF,100V 1N4148 Q2C IRF6665 R9C 47K R15D 10K R17C 10K R15C 0.47uF, 400V C13C 1N4148 47K 47K R12A R12B 10K 25 C10A R17A 10K D1A 22R 4.7R D1D 0 22uF, 16V R15A VS3 HO3 28 26 27 VS4 HO4 VB4 29 32 31 NC COM 30 C9A 10uF,16V R16D 3.9K 13 D2C 1N4148 C10C D4 1N4148 R4 0R0 or N/A 1N4148 C19D D3 C8 10uF, 16V R4C 100K 1% Q1C IRF6665 R20C R18D D2D 15 1N4148 CSD R4D 100K 1% 4CH2 3 2 1CH1 CH1 OUTPUT R12C 0R0 or N/A CH1 OUTPUT GND GND CH2 OUTPUT 4.7R 16 VB1 P2 2.2K R14B 14 CSH1 CSD 2 R22 10R 33 COMP1 1 R1 DT LO1 GND R24C L2 22uH R24D 2.2K R17D 10K R12D 47K 48 LO2 IN1 1 2 3 4 2.2K CH2 OUTPUT 22R CH3 OUTPUT GND GND CH4 OUTPUT GND C9B 10uF,16V C10D C3D 2.2nF,50V COMP2 22uF, 16V 47 Q2B IRF6665 R9B R24B GND 17 HO1 46 Q1B IRF6665 22R 4.7R 1N4148 18 NC VS1 45 1nF,50V Q2A IRF6665 R20B R18A D2A 19 NC VCC2 12 C4D -B IN2 11 120R 2.2nF,50V C3C 2.2nF,50V VAA VS2 R2D VSS HO2 100pF, 50V C2D 44 VB2 C1D 120R 2.2nF,50V 4.7uF,10V 9 10uF, 16V R1D 22K VAA 43 C7 1nF,50V C4C 10 100pF, 50V R3D 4.7K C5D R2C NC C1C C2C 8 C12D 220pF GND CH1 INPUT R7 10R 4.7K 10uF, 16V R1C 22K GND 22R 20 COM2 MLQP48_4CH -B R3C C5C VSS 42 GND Q1A IRF6665 R20A 3.9K 21 LO4 IC1 R16A 22 LO3 IN4 CSH2 4.7uF,10V COMP4 NC 41 C6 R18B R9A 23 CSH3 NC R6 10R 24 VB3 IN3 P3 R24A 2.2K CH4 OUTPUT 22R 7 10uF, 16V COMP3 6 40 C4B 1nF,50V C12C 220pF CH2 INPUT R17B 10K 4.7R CSH4 1K R2B 120R GND GND 39 VCC 37 2.2nF,50V 34 R13 R11 8.2K C3B 5 C5B C12B 220pF 2.2nF,50V NC CH3 INPUT C4A 1nF,50V 38 C2B NC GND CH4 8 GND 7 CH3 6 GND 5 GND 4 CH2 3 GND 2 CH1 1 R2A 120R 4.7K 4 100pF, 50V R3B 4.7K C12A 220pF CN1 R16B 3.9K R22A 10K R12 R10 C1B R3A 35 36 10uF, 16V R1B 22K VREF 100pF, 50V C5A NC C1A CH4 INPUT C3A 2.2nF,50V 3 C2A 2.2nF,50V 22K OCSET R4A 100K 1% R1A C10B 22uF, 16V D1B 1N4148 D2B 1N4148 R15B 10K R4B 100K 1% CH3 OUTPUT L1 22uH NC 2.2K R22B 10K R14A 4.7R C33 0.1uF, 50V Z1 24V R38 10R R23B 100k C17B 1000uF,35V -B +B GND -B 3 2 1 IRAUDAMP8 Fabrication Materials Table 1 IRAUDAMP8 Electrical Bill of Materials Quantity Value Description CAP CER .1UF 50V 10% X7R 0603 CAP CERAMIC 100PF 50V NP0 0603 C1 490-1519-1-ND Vender Murata Electronics North America C1A, C1B, C1C, C1D C2A, C2B, C2C, C2D, C3A, C3B, C3C, C3D, C35 399-1061-1-ND Kemet 490-1500-1-ND Murata Electronics North America C4A, C4B, C4C, C4D 399-1082-1-ND Kemet C5A, C5B, C5C, C5D PCE4179CT-ND Panasonic - ECG C6, C7 478-1429-1-ND CAP CER 10UF 16V Y5V 1206 C8 490-3383-1-ND CAP CER 10UF 16V Y5V 0805 C9A, C9B C10A, C10B, C10D, C37 C12A, C12B, C12D C13A, C13B, C13D C14A, C14B, C14D AVX Corporation Murata Electronics North America Murata Electronics North America 1 0.1uF,50V 4 100pF, 50V 9 2.2nF,50V 4 1nF,50V 4 10uF, 16V 2 4.7uF,10V CAP CER 2200PF 50V 10% X7R 0603 CAP 1000PF 50V CERAMICX7R 0603 CAP 10UF 16V HA ELECT SMD CAP CERM 4.7UF 10V Y5V 0805 1 10uF, 16V 2 10uF,16V 5 4 4 22uF, 16V 220pF 0.47uF, 400V 4 0.1uF, 63V 2 1000uF,35V 2 0.1uF,50V 4 0.1uF,100V 1 2.2uF, 50V 1 0.1uF, 50V 1 0.01uF, 25V 1 0.01uF, 50V 2 0.01uF, 50V 1 ED1520-ND 10 1N4148 1 DIODE1 1 4.7V 1 Blue LED 1 MLQP48_4CH 1 1 LTC1799 LM26CIM5XHA TC7W00FFCTND 1 LM5007 1 www.irf.com CAP CER 22UF 16V X7R 1210 CAP CER 220PF 50V 10% X7R 0603 CAP .47UF 400V METAL POLYPRO CAP FILM MKP .1UF 63VDC 2% CAP 1000UF 35V ELECT SMG RAD CAP .10UF 50V CERAMIC X7R 1206 CAP CER .10UF 100V X7R 10% 0805 CAP CER 2.2UF 50V X7R 1206 CAP CER .1UF 50V 10% X7R 0805 CAP 10000PF 25V CERM X7R 0603 CAP CER 10000PF 50V 20% X7R 0603 CAP 10000PF 50V CERAMIC X7R 0603 TERMINAL BLOCK 3.5MM 8POS PCB DIODE SWITCH 100V 400MW SOD-123 DIODE SCHOTTKY 100V 1.5A SMA DIODE ZENER 500MW 4.7V SOD123 LED BLUE CLEAR THIN 0805 SMD 4ch Audio Class D Controller IC OSCILLATOR RES SET TSOT23-5 IC THERMOSTAT PRESET SOT23-5 IC GATE NAND DUAL 2INPUT 8-SOP IC REG SW STEP-DOWN 80V 8-LLP Designator Part Number 490-3347-1-ND C10C, 445-3945-1-ND C12C, 490-1483-1-ND TDK Corporation Murata Electronics North America C13C, 495-1315-ND BC2054-ND EPCOS Inc Vishay/BC Components C17A, C17B 565-1086-ND United Chemi-Con C17C, C17D C19A, C19B, C19C, C19D 399-1249-1-ND Kemet 445-1418-1-ND C32 490-3367-1-ND C33 490-1666-1-ND TDK Corporation Murata Electronics North America Murata Electronics North America C34 PCC1763CT-ND C36 490-1511-1-ND C61, C62 399-1091-1-ND CN1 D1A, D1B, D1C, D1D, D2A, D2B, D2C, D2D, D3, D4 ED1520-ND Kemet On Shore Technology Inc 1N4148W-FDICT-ND Diodes Inc D7 10MQ100NPBFCT-ND Vishay/Semiconductors D51 MMSZ4V7T1GOSCT-ND ON Semiconductor C14C, Panasonic - ECG Murata Electronics North America DS1 160-1645-1-ND Lite-On Inc IC1 International Rectifier IC2 IR2093MPBF LTC1799CS5#TRMPBFCTND IC6 LM26CIM5-XHACT-ND IC8 TC7W00FFCT-ND IC9 LM5007SDCT-ND IRAUDAMP8 REV 1.0 Linear Technology National Semiconductor Toshiba National Semiconductor Page 27 of 34 2 22uH 1 220uH 1 Header 3 2 SP OUT 1 FX491 8 IRF6665 1 MMBT5401 3 MMBT5551 1 ZX5T853 1 ZX5T953 1 0R0 7 22K 4 120R 4 4.7K 4 100K 1% 4 10R 8 22R 1 2.2K 1 8.2K 2 1K 6 4.7R 10K Fixed inductors for Digital Audio Amplifier POWER INDUCTOR 220UH 0.49A SMD CONN TERM BLOCK PCB 5.0MM 3POS TERMINAL BLOCK 3.5MM 4POS PCB TRANS HP NPN 60V 1000MA SOT-23 MOSFET N-CH 100V 4.2A DIRECTFET TRANS 150V 350MW PNP SMD SOT-23 TRANS NPN 160V 350MW SMD SOT-23 TRANSISTOR 4.5A 100V SOT-89 TRANSISTOR PNP 3.5A 100V SOT-89 RES ZERO OHM 1/10W 5% 0603 SMD RES 22K OHM 1/10W 5% 0603 SMD RES 120 OHM 1/10W 5% 0603 SMD RES 4.7K OHM 1/10W 5% 0603 SMD RES 100K OHM 1/8W 1% 0805 SMD RES 10 OHM 1/10W 5% 0603 SMD RES 22 OHM 1/10W 5% 0603 SMD RES 2.2K OHM 1/10W 5% 0603 SMD RES 8.2K OHM 1/10W 5% 0603 SMD RES 1.0K OHM 1/10W 5% 0603 SMD RES 4.7 OHM 1/10W 5% 0603 SMD RES 10K OHM 1/10W 5% 0603 SMD' 16 4 3.9K 4 1R 4 10R,1W 4 100k 4 2.2K 1 5.1k 1 5.1k 6 47k 1 120k 1 3.3k www.irf.com RES 3.9K OHM 1/10W 5% 0603 SMD RES 1.0 OHM 1/8W 5% 0805 SMD RES 10 OHM 1W 1% 2512 SMD RES 100K OHM 1/10W 5% 0603 SMD RES 2.2K OHM 1/8W 5% 0805 SMD RES 5.1K OHM 1/8W 5% 0805 SMD RES 5.1K OHM 1/10W 5% 0603 SMD RES 47K OHM 1/10W 5% 0603 SMD RES 120K OHM 1/10W 5% 0603 SMD RES 3.3K OHM 1/10W 5% 0603 SMD L1, L2 DAEPW-M185X TOKO L5 308-1538-1-ND Sumida Corporation P1 281-1415-ND P2, P3 ED1516-ND Weidmuller On Shore Technology Inc Q1 Q1A, Q1B, Q1C, Q1D, Q2A, Q2B, Q2C, Q2D FMMT491CT-ND Zetex Inc IRF6665TRPBFCT-ND International Rectifier Q2 MMBT5401-FDICT-ND Diodes Inc Q3, Q4, Q5 MMBT5551-FDICT-ND Diodes Inc Q8 ZX5T853ZCT-ND Zetex Inc Q9 ZX5T953ZCT-ND Zetex Inc R1 R1A, R1B, R1C, R1D, R3, R51, R59 P0.0GCT-ND Panasonic - ECG RHM22KGCT-ND Rohm R2A, R2B, R2C, R2D RHM120GCT-ND Rohm R3A, R3B, R3C, R3D RHM4.7KGCT-ND Rohm R4A, R4B, R4C, R4D RHM100KCRCT-ND Rohm R6, R7, R22, R38 R9A, R9B, R9C, R9D, R20A, R20B, R20C, R20D RHM10GCT-ND Rohm RHM22GCT-ND Rohm R10 RHM2.2KGCT-ND Rohm R11 RHM8.2KGCT-ND Rohm R13, R32 R14A, R14B, R18A, R18B, R18C, R18D R15A, R15B, R15C, R15D, R17A, R17B, R17C, R17D, R22A, R22B, R22C, R22D, R53, R54, R61, R62 R16A, R16B, R16C, R16D R19A, R19B, R19C, R19D R21A, R21B, R21C, R21D RHM1.0KGCT-ND Rohm RHM4.7GCT-ND Rohm RHM10KGCT-ND Rohm RHM3.9KGCT-ND Rohm RHM1.0ARCT-ND Rohm PT10AECT-ND Panasonic - ECG R23A, R23B, R39, R40 R24A, R24B, R24C, R24D RHM100KGCT-ND Rohm RHM2.2KARCT-ND Rohm R31 RHM5.1KARCT-ND Rohm R36 R37, R50, R55, R56, R57, R58 RHM5.1KGCT-ND Rohm RHM47KGCT-ND Rohm R41 RHM120KGCT-ND Rohm R42 RHM3.3KGCT-ND Rohm IRAUDAMP8 REV 1.0 Page 28 of 34 2 510R,1W 2 33k 2 15k 1 10K 1 24V 1 15V 1 39V 1 18V 2 5.6V RES 510 OHM 1W 5% 2512 SMD RES 33K OHM 1/10W 5% 0603 SMD RES 15K OHM 1/10W 5% 0603 SMD POT 10K OHM 3MM CERM SQ TOP SMD DIODE ZENER 500MW 24V SOD123 DIODE ZENER 500MW 15V SOD123 DIODE ZENER 39V 500MW SOD-123 DIODE ZENER 500MW 18V SOD123 DIODE ZENER 500MW 5.6V SOD123 R43, R44 PT510XCT-ND Panasonic - ECG R45, R46 RHM33KGCT-ND Rohm R52, R60 RHM15KGCT-ND Rohm VR1 ST32ETB103CT-ND Copal Electronics Inc Z1 BZT52C24-FDICT-ND Diodes Inc Z2 BZT52C15-FDICT-ND Diodes Inc Z3 BZT52C39-FDICT-ND Diodes Inc Z4 BZT52C18-FDICT-ND Diodes Inc Z5, Z6 MMSZ5V6T1GOSCT-ND ON Semiconductor Table 2 IRAUDAMP8 Mechanical Bill of Materials Quantity Value Description Designator Digikey P/N Vendor H729ND Building Fasteners 7 Washer #4 SS WASHER LOCK INTERNAL #4 SS Lock washer 1, Lock washer 2, Lock washer 3, Lock washer 4, Lock washer 5, Lock washer 6 Lock washer 7 1 PCB Print Circuit Board IRAUDAM8M_Rev 3.0 .PCB PCB 1 7 Screw 440X5/16 SCREW MACHINE PHILLIPS 4-40X5/16 Screw 1, Screw 2, Screw 3, Screw 4, Screw 5, Screw 6, Screw 7, H343ND 4 Stand off 0.5" STANDOFF HEX 440THR .500"L ALUM Stand Off 1, Stand Off 2, Stand Off 3, Stand Off 4 1893KND 1/16 AAVID 4880G THERMAL PAD .080" 4X4" GAPPAD thermal pad under heatsink BER164ND www.irf.com IRAUDAMP8 REV 1.0 Custom Building Fasteners Keystone Electronics Thermalloy Page 29 of 34 IRAUDAMP8 Hardware IRAUDAMP8 Heat Spreader Note: All dimensions are in millimeters Tolerances are ±0.1mm Material:ALUMINUM All thread holes are 4-40 X 8mm dip ,minimum 4.5 3 3 4.5 16 10.5 6 1.6 12 14 12 6 8 27 27 10 Fig 23 Heat Spreader . Screw H343-ND Thermal Pad Th l d Lock washer Screw H343-ND Screw H343-ND Screw H343-ND Stand Off 3 1893K-ND Lock washer Lock washer Stand Off 2 Lock washer 1893K-ND Lock washer Lock washer Stand Off 4 1893K-ND Lock washers H729-ND Screw Screw Screw Stand Off 1 1893K-ND Screws H343-ND Fig 24 Hardware Assemblies www.irf.com IRAUDAMP8 REV 1.0 Page 30 of 34 IRAUDAMP8 PCB Specifications PCB: 1. 2. 3. 4. 5. 6. Two Layers SMT PCB with through holes 1/16 thickness 2/0 OZ Cu FR4 material 10 mil lines and spaces Solder Mask to be Green enamel EMP110 DBG (CARAPACE) or Enthone Endplate DSR-3241or equivalent. 7. Silk Screen to be white epoxy non conductive per IPC–RB 276 Standard. 8. All exposed copper must finished with TIN-LEAD Sn 60 or 63 for 100u inches thick. 9. Tolerance of PCB size shall be 0.010 –0.000 inches 10. Tolerance of all Holes is -.000 + 0.003” 11. PCB acceptance criteria as defined for class II PCB’S standards. Gerber Files Apertures Description: All Gerber files stored in the attached CD-ROM were generated from Protel Altium Designer Altium Designer 6. Each file name extension means the following: 1. .gtl 2. .gbl 3. .gto 4. .gbo 5. .gts 6. .gbs 7. .gko 8. .gm1 9. .gd1 10. .gg1 11. .txt 12. .apr Top copper, top side Bottom copper, bottom side Top silk screen Bottom silk screen Top Solder Mask Bottom Solder Mask Keep Out, Mechanical1 Drill Drawing Drill locations CNC data Apertures data Additional files for assembly that may not be related with Gerber files: 13. .pcb 14. .bom 15. .cpl 16. .sch 17. .csv 18. .net 19. .bak 20. .lib www.irf.com PCB file Bill of materials Components locations Schematic Pick and Place Components Net List Back up files PCB libraries IRAUDAMP8 REV 1.0 Page 31 of 34 Fig 25 IRAUDAMP8 PCB Top Overlay (Top View) www.irf.com IRAUDAMP8 REV 1.0 Page 32 of 34 Fig 26 IRAUDAMP8 PCB Bottom Layer (Top View) www.irf.com IRAUDAMP8 REV 1.0 Page 33 of 34 Revision changes descriptions Revision Rev 1.0 Rev 1.1 Changes description Released ROHS Compliant (BOM Updated) Date Jan, 08th 2009 May,29th 2009 WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245 Tel: (310) 252-7105 Data and specifications subject to change without notice. 01/29/2009 www.irf.com IRAUDAMP8 REV 1.0 Page 34 of 34