Infineon Technologies IRAUDAMP8 User Manual

IRAUDAMP8

120W x 4 Channel Class D Audio Power Amplifier

Using the IRS2093M and IRF6665

By

Jun Honda, Yasushi Nishimura and Liwei Zheng

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

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CAUTION:

IRAUDAMP8 REV 1.0

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

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IRAUDAMP8 REV 1.0

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: 120W x 4 channels,
Residual Noise: 200V, IHF-A weighted, AES-17 filter
Distortion: 0.012% THD+N @ 60W, 4Ω
Efficiency: 90% @ 120W, 4Ω, single-channel driven, Class D stage
Multiple Protection Features: 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)

PWM Modulator: Self-oscillating half-bridge topology with optional clock synchronization

Specifications

General Test Conditions (unless otherwise noted) Notes / Conditions

Supply Voltages ±35V
Load Impedance 4Ω
Self-Oscillating Frequency 400kHz No input signal, Adjustable
Gain Setting 26.5dB 1Vrms input yields rated power

Electrical Data Typical Notes / Conditions

IR Devices Used 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

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IRAUDAMP8 REV 1.0

Standby Supply Current ±100mA No input signal
Total Idle Power Consumption 7W No input signal
Channel Efficiency 90% Single-channel driven,

120W, Class D stage

.

Audio Performance

*Before

Demodula

tor

THD+N, 1W
THD+N, 10W
THD+N, 60W
THD+N, 100W

Dynamic Range 101dB 101dB

Residual Noise, 22Hz - 20kHzAES17

0.015%

0.006%

0.005%

0.015%

200V

Class D

Output

0.015%

0.008%

0.012%

0.02%

200V

Notes / Conditions

1kHz, Single-channel driven

A-weighted, AES-17 filter,
Single-channel operation
Self-oscillating – 400kHz

Damping Factor 2000 48 1kHz, relative to 4Ω load
Channel Separation 85dB

85dB
75dB

Frequency Response : 20Hz-20kHz

N/A ±1dB

: 20Hz-35kHz

78dB
77dB
70dB

±3dB

100Hz
1kHz
10kHz

1W, 4Ω - 8Ω Load

Thermal Performance Typical Notes / Conditions

Idling

4ch x 15W (1/8 rated power)

4ch x 120W (Rated power)

Physical Specifications

Dimensions 3.94”(L) x 2.83”(W) x 0.85”(H)

Weight 0.140kgm

T

C

T

PCB

T

C

T

PCB

T

C

T

PCB

=30C

=42C

=54C

=71C

=80C

=106C

No signal input, T

Continuous, T

At OTP shutdown @ 150 sec,
T

=25C

A

100 mm (L) x 72 mm (W) x 21.5 mm(H)

A

=25C

A

=25C

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IRAUDAMP8 REV 1.0

A

r

Connection Setup

Frequency adjustor

35 V, 10 A DC supply

udio Signal Generato

CH1 CH2 CH3 CH4

VR1

Output

CH2 CH1 +B GND -B CH4 CH3

IRS2093

Input

G

35 V, 10 A DC supply

Output

DS1

,VCC INDICATOR

IRF6665

250W,4ΩNon-inductive

Connector Description

CH1 IN CN1 Analog input for CH1
CH2 IN CN1 Analog input for CH2
CH3 IN CN1 Analog input for CH3
CH4 IN CN1 Analog input for CH4
SUPPLY P1 Positive and negative supply (+B / -B)
CH1 OUT P2 Output for CH1
CH2 OUT P2 Output for CH2
CH3 OUT P3 Output for CH3
CH4 OUT P3 Output for CH4

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Fig 1 Typical Test Setup

IRAUDAMP8 REV 1.0

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 mV

12. Connect the audio signal generator to CN2(Input of CH1,CH2,CH3,CH4)

13. Sweep the audio signal voltage from 15 mV

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 V

input generates an output voltage of 21.2 V

RMS

R4A/(R3A), determines the voltage gain of IRAUDAMP8.

output.

RMS

RMS

to 1 V

RMS

.

. The ratio,

RMS

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 mV

21. Run Ap test programs for all subsequent tests as shown in Fig 2- Fig 7below.

RMS

to 1 V

RMS

.

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IRAUDAMP8 REV 1.0

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 200200m 500m 1 2 5 10 20 50 100

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

+3

+2

+1

-0

-1

d

-2

B

-3

r

-4

A

-5

-6

-7

-8

-9

-10
20 200k50 100 200 500 1k 2k 5k 10k 20k 50k 100k

CH1-Blue; CH2-Yellow; CH3-Red; CH4-Cyan

±B Supply = ±35V, 4 Ω Resistive Load

Fig 3 IRAUDAMP8, Frequency response

Hz

T

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IRAUDAMP8 REV 1.0

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 20k50 100 200 500 1k 2k 5k 10k

Hz

Red CH1, 10W Output
Blue CH1, 50W Output

Fig 4 THD+N Ratio vs. Frequency

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CH1-Blue; CH2-Yellow; CH3-Red; CH4-Cyan

Fig 5, 1V output Frequency Spectrum

IRAUDAMP8 REV 1.0

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

-60

B

-70

-80

-90

-100

-110

-120
20 20k50 100 200 500 1k 2k 5k 10k

Hz

Red CH1 – CH2, 60W

Blue CH2 – CH1, 60W

Fig 7, Channel separation vs. frequency

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IRAUDAMP8 REV 1.0

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

.

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IRAUDAMP8 REV 1.0

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 R

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

DS(ON)

100%

90%

80%

70%

60%

50%

40%

30%

Efficiency (%)

20%

10%

0%

0 50 100 150

AMP8 35V 4ohms

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.

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IRAUDAMP8 REV 1.0

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.
details). TIM’s manufacturer thickness, conductivity, & etc. determine pressure requirement.
Below shows selection options recommended:

(Refer to AN-1035 for more

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Fig 10 TIM Information

IRAUDAMP8 REV 1.0

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

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IRAUDAMP8 REV 1.0

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

-40

d
B
V

-50

-60

-70

-80

-90
20 40k50 100 200 500 1k 2k 5k 10k 20k

Hz

ColorSweep Trace Line Sty le Thick Data Axis Comment

1 1 Red Solid 2 Anlr.Ampl Left

Fig 12 Amp8 Power Supply Rejection Ratio (PSRR)

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IRAUDAMP8 REV 1.0

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

VS pin

VS pin

VS pin

CSD pin

CSD pin

VS pin

Load current

Positive OCP Negative OCP

Fig 13 Positive and Negative OCP Waveforms

.

OCP Waveforms Showing CSD Trip and Hiccup

VS pin

VS pin

Load current

Load current

Load current

Load current

CSD pin

Load current

CSD pin

Fig 14 OCP Response with Continuous Short Circuit

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IRAUDAMP8 REV 1.0

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.

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IRAUDAMP8 REV 1.0

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

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IRAUDAMP8 REV 1.0

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

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IRAUDAMP8 REV 1.0

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.

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IRAUDAMP8 REV 1.0

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 R1 R2 DT/SD Voltage

DT1 <10k Open Vcc
DT2
DT3

5.6k 4.7k

8.2k 3.3k

DT4 Open <10k COM

Recommended Resistor Values for Dead Time Selection

0.46 x Vcc

0.29 x Vcc

Dead-time

45nS

65nS

IRS2093M

>0.5mA

Vcc

R1

85nS

105nS

Vcc 0.57 xVcc 0.36xVcc 0.23xVcc

V

DT

R2

DT

COM

Fig 17 Dead-time Settings vs. VDT Voltage

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IRAUDAMP8 REV 1.0

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.

R52

15k

R60

15k

R59

22k

R51

22k

Q5
MMBT5551

5

OS

4

VCC

D51

4.7V

IC6
LM26CIM5-XHA

1

HT

2

GND

3

VT

OTP

SD

GND

R56

47k

Q3

MMBT5551

OVP UVP

R54

10k

Z3

R53

39V

10k

MMBT5551

R55

47k

Q4

R57

47k

Z4
18V

R50

47k

R58

47k

-B

Fig 18 DCP, OTP, UVP and OVP Protection Circuits

.

Fig 19 Simplified Functional Diagram of OCP

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IRAUDAMP8 REV 1.0

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 R

during its on state.

DS(ON)

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 R

during its on state. OCP

DS(ON)

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.

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IRAUDAMP8 REV 1.0

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 (V
driver section of the IRS2093 uses VCC to drive gates of the DirectFETs. V
(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.

) referred to the negative supply rail -B for DirectFET gate drive. The gate

CC

is referenced to –B

CC

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IRAUDAMP8 REV 1.0

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

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IRAUDAMP8 REV 1.0

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 V
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)

amplitude

RMS

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 Page 25 of 34

IRAUDAMP8 REV 1.0

www.irf.com Page 26 of 34

IRAUDAMP8 REV 1.0

R20B

22R

C4A

1nF,50V

C2A 2.2nF,50V

R2A 120R

R2B 120R

C3C

2.2nF,50V

C4C1nF,50V

C2D

2.2nF,50V

R7 10R

C6 4.7uF,10V

C7

4.7uF,10V

C2C

2.2nF,50V

R6 10R

R20A

22R

R9A

22R

R9B

22R

R9C

22R

R9D

22R

R20D

22R

R20C

22R

R21B

10R,1W

R21A

10R,1W

C13B

0.47uF, 400V

C13A

0.47uF, 400V

C13D

0.47uF, 400V

C13C

0.47uF, 400V

C14B

0.1uF, 63V

C14A

0.1uF, 63V

CH3 OUTPUT

CH4 OUTPUT

CH2 OUTPUT

CH1 OUTPUT

R15C

10K

R16C

3.9K

R17C

10K

R15D

10K

R16D

3.9K

R17D 10K

D1D 1N4148

D1C
1N4148

D2C

1N4148

R18C

4.7R

R14B

4.7R

C9B

10uF,16V

R16A

3.9K

D1A

1N4148

R15A

10K

R17A

10K

D2B
1N4148

R18B

4.7R

R17B

10K

D1B
1N4148

R16B

3.9K

R15B 10K

R14A

4.7R

C9A

10uF,16V

R13 1K

R12 NC

R11 8.2K R10 2.2K

R4B

100K 1%

R4A

100K 1%

R2C

120R

R3C 4.7K

R1C 22K

R2D

120R

R1D 22K

R4C

100K 1%

R4D

100K 1%

C4D 1nF,50V
C3D

2.2nF,50V

R3A 4.7K

R1B 22K

R3B 4.7K

R1A 22K

C1A 100pF, 50V

R3D 4.7K

C3A 2.2nF,50V

C2B

2.2nF,50V

C3B 2.2nF,50V

C4B

1nF,50V

D2A

1N4148

R18A

4.7R

D2D

1N4148

R18D

4.7R

R21D

10R,1W

R21C

10R,1W

C14D

0.1uF, 63V

C14C

0.1uF, 63V

NC3NC2NC

1

CSD

48

GND

41

IN4

40

COMP4

39

IN3

38

VAA

43

NC

5

VS4

27

CSH4

30

NC

31

COMP2

45

LO2

16

VCC2

17

CSH3

23

VS3

26

VB2

8

HO4

28

VCC

33

COMP1

47

LO3

22

VREF

36

OCSET

35

LO1

15

LO4

21

VB3

24

HO3

25

COM2

20

NC

18

NC

6

COM

32

HO29VS2

10

NC

4

VS111HO1

12

VB1

13

CSH1

14

VB4

29

DT

34

IN2

44

IN1

46

CSH2

7

NC

19

COMP3

37

VSS

42

-B

0

IC1

MLQP48_4CH

C19A

0.1uF,100V

R19A

1R

R19D

1R

L1
22uH

L2
22uH

C19B

0.1uF,100V

R19B

1R

C19C

0.1uF,100V

R19C

1R

R22

10R

D3

1N4148

R22D

10K

R22C 10K

R22B 10K

Q1A
IRF6665

Q2A
IRF6665

Q1B
IRF6665

Q2B
IRF6665

Q2D
IRF6665

Q1C
IRF6665

Q2C
IRF6665

Q1D
IRF6665

C1B 100pF, 50V

C1C 100pF, 50V

C1D 100pF, 50V

GND

GND

GND

GND

CSD

GND

GND

GND

GND

D4
1N4148

C5A 10uF, 16V

C5B 10uF, 16V

C5C 10uF, 16V

C5D 10uF, 16V

R24B 2.2K

R24A 2.2K

R24D 2.2K

R24C 2.2K

R3

22k

C1

0.1uF,50V

VR1

10K

C40

N/A

C41

N/A

HT1OS

5

VT

3

GND

2

VCC

4

IC6
LM26CIM5- XHA

R51

22k

D51

4.7V

R52

15k

C10C

22uF, 16V

C10B

22uF, 16V

C10A

22uF, 16V

C10D

22uF, 16V

C8

10uF, 16V

VCC1OUT

5

SET

3

GND

2

DIT

4

IC2
LTC1799

R43

510R,1W

R44

510R,1W

C17B

1000uF,35V

C17A

1000uF,35V

C17C

0.1uF,50V

C17D

0.1uF,50V

R23B

100k

R23A

100k

1A

1

1B

2

2Y

3

GND42A

5

2B

6

1Y

7

VCC

8

IC8

TC7W00FFCT-ND

L5 220uH

C32

2.2uF, 50V

C37

22uF, 16V

C33

0.1uF, 50V

C34

0.01uF, 25V

C35

2200pF,50V

C36

0.01uF, 50V

R39

100k

R40

100k

R42

3.3k

R32

1k

R41

120k

D7

R31

5.1k

DS1

Q1

FX491

Q2
MMBT5401

R38

10R

R37

47k

Z1
24V

Z2

15V

R36

5.1k

SW

1

BST

2

RCL

3

RTN

4

VIN

8

VCC

7

RON/SD

6

FB

5

IC9

LM5007

Q5
MMBT5551

R59

22k

Q3

MMBT5551

Q4

MMBT5551

R54

10k

R55

47k

R53

10k

R57

47k

R50

47k

R58

47k

Z3
39V

Z4
18V

OVP UVP

+B

GND

-B

R46

33k

1

2

3

4

5

6

7

8

CN1

CH1

GND

CH2

GND

GND

CH3

GND

CH4

CH4 INPUT

CH3 INPUT

CH2 INPUT

CH1 INPUT

1

2

3

4

P2

1
2
3
4

P3

1

2

3P1+B

GND

-B

CH2 OUTPUT

CH1 OUTPUT

GND

GND

CH3 OUTPUT

CH4 OUTPUT

GND

GND

-5v

+5v

VCC

C12A 220pF

VSS
VAA

-B

R22A

10K

C19D

0.1uF,100V

SD

R56

47k

CH2

CH1

R60

15k

C12B 220pF

C12C 220pF

C12D 220pF

Q8 ZX5T853

Q9

ZX5T 953

R45

33k

Z5

5.6V

Z6

5.6V

R4 0R0 or N/A

R1

0R0 or N/A

GND

GND

C61

0.01uF, 50V

R61

10k

R62

10k

For EMI

C62

0.01uF, 50V

R12A

47K

R12B

47K

R12C

47K

R12D

47K

Fig 22 IRAUDAMP8 Schematic

Schematic

IRAUDAMP8 Fabrication Materials

Table 1 IRAUDAMP8 Electrical Bill of Materials

Quantity Value Description Designator Part Number Vender

1 0.1uF,50V

4 100pF, 50V

9 2.2nF,50V

4 1nF,50V

4 10uF, 16V

2 4.7uF,10V

1 10uF, 16V CAP CER 10UF 16V Y5V 1206 C8 490-3383-1-ND

2 10uF,16V CAP CER 10UF 16V Y5V 0805 C9A, C9B 490-3347-1- ND

5 22uF, 16V CAP CER 22UF 16V X7R 1210

4 220pF

4 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 4ch Audio Class D Controller IC1 IR2093MPBF International Rectifier

1 LTC1799

1

1

1 LM5007

LM26CIM5­XHA
TC7W00FFCT­ND

CAP CER .1UF 50V 10% X7R
0603
CAP CERAMIC 100PF 50V
NP0 0603

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

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

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

C1 490-1519-1-ND

C1A, C1B, C1C, C1D 399-1061-1-ND Kemet
C2A, C2B, C2C, C2D,
C3A, C3B, C3C, C3D,
C35

C4A, C4B, C4C, C4D 399-1082-1-ND Kemet

C5A, C5B, C5C, C5D PCE4179CT-ND Panasonic - ECG

C6, C7 478-1429-1-ND AVX Corporation

C10A, C10B, C10C,
C10D, C37
C12A, C12B, C12C,
C12D
C13A, C13B, C13C,
C13D
C14A, C14B, C14C,
C14D

C17A, C17B 565-1086-ND United Chemi-Con

C17C, C17D 399-1249-1-ND Kemet
C19A, C19B, C19C,
C19D

C32 490-3367-1-ND

C33 490-1666-1-ND

C34 PCC1763CT-ND Panasonic - ECG

C36 490-1511-1-ND

C61, C62 399-1091-1-ND Kemet

CN1 ED1520-ND
D1A, D1B, D1C, D1D,
D2A, D2B, D2C, D2D,
D3, D4

D7 10MQ100NPBFCT-ND Vishay/Semiconductors

D51 MMSZ4V7T1GOSCT-ND ON Semiconductor

DS1 160-1645-1-ND Lite-On Inc

IC2

IC6 LM26CIM5-XHACT-ND

IC8 TC7W00FFCT-ND Toshiba

IC9 LM5007SDCT-ND

Murata Electronics
North America

490-1500-1-ND

445-3945-1-ND TDK Corporation

490-1483-1-ND

495-1315-ND EPCOS Inc

BC2054-ND

445-1418-1-ND TDK Corporation

1N4148W-FDICT-ND Diodes Inc

LTC1799CS5#TRMPBFCT­ND

Murata Electronics
North America

Murata Electronics
North America
Murata Electronics
North America

Murata Electronics
North America

Vishay/BC
Components

Murata Electronics
North America
Murata Electronics
North America

Murata Electronics
North America

On Shore Technology
Inc

Linear Technology
National
Semiconductor

National
Semiconductor

www.irf.com Page 27 of 34

IRAUDAMP8 REV 1.0

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

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

Fixed inductors for Digital
Audio Amplifier L1, L2 DAEPW-M185X TOKO
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 Q3, Q4, Q5 MMBT5551-FDICT-ND Diodes Inc
TRANSISTOR 4.5A 100V
SOT-89 Q8 ZX5T853ZCT-ND Zetex Inc
TRANSISTOR PNP 3.5A 100V
SOT-89 Q9 ZX5T953ZCT-ND Zetex Inc
RES ZERO OHM 1/10W 5%
0603 SMD R1 P0.0GCT-ND Panasonic - ECG
RES 22K OHM 1/10W 5%
0603 SMD
RES 120 OHM 1/10W 5% 0603
SMD R2A, R2B, R2C, R2D RHM120GCT-ND Rohm
RES 4.7K OHM 1/10W 5%
0603 SMD R3A, R3B, R3C, R3D RHM4.7KGCT-ND Rohm
RES 100K OHM 1/8W 1%
0805 SMD R4A, R4B, R4C, R4D RHM100KCRCT-ND Rohm
RES 10 OHM 1/10W 5% 0603
SMD R6, R7, R22, R38 RHM10GCT-ND Rohm

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 R13, R32 RHM1.0KGCT-ND Rohm
RES 4.7 OHM 1/10W 5% 0603
SMD

RES 10K OHM 1/10W 5%
0603 SMD'

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 R23A, R23B, R39, R40 RHM100KGCT-ND Rohm
RES 2.2K OHM 1/8W 5% 0805
SMD
RES 5.1K OHM 1/8W 5% 0805
SMD R31 RHM5.1KARCT-ND Rohm
RES 5.1K OHM 1/10W 5%
0603 SMD R36 RHM5.1KGCT-ND Rohm
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

L5 308-1538-1-ND Sumida Corporation

P1 281-1415-ND Weidmuller

P2, P3 ED1516-ND

Q1 FMMT491CT-ND Zetex Inc
Q1A, Q1B, Q1C, Q1D,
Q2A, Q2B, Q2C, Q2D

Q2 MMBT5401-FDICT-ND Diodes Inc

R1A, R1B, R1C, R1D,
R3, R51, R59 RHM22KGCT-ND Rohm

R9A, R9B, R9C, R9D,
R20A, R20B, R20C,
R20D RHM22GCT-ND Rohm

R10 RHM2.2KGCT-ND Rohm

R11 RHM8.2KGCT-ND Rohm

R14A, R14B, R18A,
R18B, R18C, R18D RHM4.7GCT-ND Rohm
R15A, R15B, R15C,
R15D, R17A, R17B,
R17C, R17D, R22A,
R22B, R22C, R22D,
R53, R54, R61, R62
R16A, R16B, R16C,
R16D RHM3.9KGCT-ND Rohm
R19A, R19B, R19C,
R19D RHM1.0ARCT-ND Rohm
R21A, R21B, R21C,
R21D PT10AECT-ND Panasonic - ECG

R24A, R24B, R24C,
R24D RHM2.2KARCT-ND Rohm

R37, R50, R55, R56,
R57, R58 RHM47KGCT-ND Rohm

R41 RHM120KGCT-ND Rohm

R42 RHM3.3KGCT-ND Rohm

IRF6665TRPBFCT-ND International Rectifier

RHM10KGCT-ND Rohm

On Shore Technology
Inc

www.irf.com Page 28 of 34

IRAUDAMP8 REV 1.0

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 R43, R44 PT510XCT-ND Panasonic - ECG
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 Z4 BZT52C18-FDICT-ND Diodes Inc
DIODE ZENER 500MW 5.6V
SOD123 Z5, Z6 MMSZ5V6T1GOSCT-ND ON Semiconductor

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

Table 2 IRAUDAMP8 Mechanical Bill of Materials

Quantity Value Description Designator

Lock washer 1, Lock washer 2,
Lock washer 3, Lock washer 4,

Lock washer 5, Lock washer 6

Lock washer 7

PCB 1 Custom

Screw 1, Screw 2, Screw 3,
Screw 4, Screw 5, Screw 6,

Stand Off 1, Stand Off 2, Stand

thermal pad under heatsink

Screw 7,

Off 3, Stand Off 4

7 Washer #4 SS

1 PCB

7

4 Stand off 0.5"

1/16 AAVID 4880G

Screw 4-

40X5/16

WASHER LOCK

INTERNAL #4 SS

Print Circuit Board

IRAUDAM8M_Rev

3.0 .PCB

SCREW MACHINE

PHILLIPS 4-40X5/16

STANDOFF HEX 4-

40THR .500"L ALUM

THERMAL PAD .080" 4X4"

GAPPAD

Digikey

P/N

H729-

ND

H343-

ND

1893K-

ND

BER164-

ND

Vendor

Building

Fasteners

Building

Fasteners

Keystone

Electro-

nics

Therm-

alloy

www.irf.com Page 29 of 34

IRAUDAMP8 REV 1.0

IRAUDAMP8 Hardware

IRAUDAMP8 Heat Spreader

All thread holes are 4-40 X 8mm dip ,minimum

4.5

16

10.5

6

1.6

12

6

3

3

12

Note:

All dimensions are in millimeters
Tolerances are ±0.1mm
Material:ALUMINUM

14

108 27 27

4.5

Fig 23 Heat Spreader

.

Screw
H343-ND

Stand Off 4
1893K-ND

Screw
H343-ND

Stand Off 3

Lock washer

1893K-ND

Lock washers
H729-ND

Lock washer

Lock washer

Screws
H343-ND

Thermal Pad

Screw
H343-ND

Lock washer

Screw

Screw

Screw

Stand Off 1
1893K-ND

Fig 24 Hardware Assemblies

Screw
H343-ND

Lock washer

Lock washer

Stand Off 2
1893K-ND

www.irf.com Page 30 of 34

IRAUDAMP8 REV 1.0

IRAUDAMP8 PCB Specifications

PCB:

1. Two Layers SMT PCB with through holes

2. 1/16 thickness

3. 2/0 OZ Cu

4. FR4 material

5. 10 mil lines and spaces

6. 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 Top copper, top side

2. .gbl Bottom copper, bottom side

3. .gto Top silk screen

4. .gbo Bottom silk screen

5. .gts Top Solder Mask

6. .gbs Bottom Solder Mask

7. .gko Keep Out,

8. .gm1 Mechanical1

9. .gd1 Drill Drawing

10. .gg1 Drill locations

11. .txt CNC data

12. .apr Apertures data

Additional files for assembly that may not be related with Gerber files:

13. .pcb PCB file

14. .bom Bill of materials

15. .cpl Components locations

16. .sch Schematic

17. .csv Pick and Place Components

18. .net Net List

19. .bak Back up files

20. .lib PCB libraries

www.irf.com Page 31 of 34

IRAUDAMP8 REV 1.0

Fig 25 IRAUDAMP8 PCB Top Overlay (Top View)

www.irf.com Page 32 of 34

IRAUDAMP8 REV 1.0

Fig 26 IRAUDAMP8 PCB Bottom Layer (Top View)

www.irf.com Page 33 of 34

IRAUDAMP8 REV 1.0

Revision changes descriptions

Revision Changes description Date

Rev 1.0 Released Jan, 08th 2009
Rev 1.1 ROHS Compliant (BOM Updated) May,29th 2009

WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245 Tel: [phone]

Data and specifications subject to change without notice. 01/29/2009

www.irf.com Page 34 of 34

IRAUDAMP8 REV 1.0

Mouser Electronics

Authorized Distributor

Click to View Pricing, Inventory, Delivery & Lifecycle Information:

International Rectifier:
IRAUDAMP8