IRAUDAMP15
35W/4Ω x 2 Channel Class D Audio Power Amplifier
Using the IR4311
By
Jun Honda, Liwei Zheng
International Rectifier suggests the following guidelines for safe operation and
handling of IRAUDAMP15 Demo board;
Always wear safety glasses whenever operating Demo Board
Avoid physical contact with exposed metal surfaces when operating Demo
Board
Turn off Demo Board when placing or removing measurement probes
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CAUTION:
IRAUDAMP15 REV 1.0
TABLE OF CONTENTS ........................... PAGE
INTRODUCTION..............................................................................3
SPECIFICATIONS ...........................................................................3
CONNECTION SETUP ....................................................................4
TEST PROCEDURES......................................................................5
PERFORMANCE AND TEST GRAPHS ..........................................5
THERMAL INFORMATION..............................................................8
SCHEMATIC ....................................................................................9
BILL OF MATERIALS ....................................................................10
PCB SPECIFICATIONS.................................................................11
REVISION CHANGES DESCRIPTIONS .......................................13
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IRAUDAMP15 REV 1.0
Introduction
The IRAUDAMP15 reference design is a two-channel, 35W/ch half-bridge Class D audio power
amplifier with single power supply. This reference design demonstrates how to use the IR4311 IC
with single power supply, implement protection circuits, and design an optimum PCB layout using
PowIRaudio integrated Class D IC. This reference design does not require additional heatsink or fan
cooling for normal operation (one-eighth of continuous rated power).The reference design provides all
the required housekeeping power supplies for ease of use. The two-channel design is scalable for
power and the number of channels.
Applications
Docking station audio systems
PC audio systems
Musical instruments
Karaoke amplifiers
Game consoles
Powered speaker systems
Car audio amplifiers
Features
Output Power: 35W x 2 channels (4Ω load)
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
Specifications
General Test Conditions (unless otherwise noted) Notes / Conditions
Supply Voltages 18-31V*
Load Impedance 2-4Ω Resistive load
Self-Oscillating Frequency 400kHz No input signal, Adjustable
Gain Setting 21.4dB 1Vrms input yields rated power
Electrical Data Typical Notes / Conditions
IR Devices Used IR4311 PowIRaudio integrated Class D IC
Modulator Self-oscillating, second order sigma-delta modulation, analog input
Power Supply Range 18-31V*
Output Power CH1-2: (1% THD+N) 26W 1kHz
Output Power CH1-2: (10% THD+N) 35W 1kHz
Rated Load Impedance 2-4Ω Resistive load
Idling Supply Current 90mA No input signal
Total Idle Power Consumption 2.8W No input signal
Distortion 0.02% THD+N @ 5W, 4Ω
Residual Noise
230V
Channel Efficiency 96%
*Power Supply Voltage Range
*R25~R28
18~27V 27~37V
220Ω 470Ω
Single power supply;
IHF-A weighted, AES-17 filter
Single-channel driven, 35W, Class D
stage
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IRAUDAMP15 REV 1.0
Connection Setup
18-31V, 3A DC supply
P3
P1
P2
100W, Non-inductive Resistors
4 Ohm 4 Ohm
SW1:PWM Shutdown/MUTE
Connector Description
Audio IN CN1 Analog input for CH1 and CH2
POWER P2 Single supply
CH1 OUT P1 Output for CH1
CH2 OUT P3 Output for CH2
CH1
Output
IR4311
FAULT
Indicator
SW1
CN1
IR4311
Audio
Input
Audio Signal Generator
Fig 1 Typical Test Setup
CH2
Output
Power
Indicator
FAULT
Indicator
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IRAUDAMP15 REV 1.0
Test Procedures
Test Setup:
1. Connect 4, 100W load to both output connectors, P1 and P3 and audio analyzer (Ap).
2. Connect Audio Signal Generator to CN1 for CH1 and CH2 respectively (Ap).
3. Connect a single power supply to P2 pre-adjusted to 18-31V as shown on Figure above
4. Turn on the power supply.
5. Turn on SW1 (right side).
6. Blue LED (Normal) stays turning on after RED LED extinguished.
7. With an Oscilloscope, monitor switching waveform at VS of CH1 and CH2.
8. Quiescent current for the power supply should be 70mA 10mA at 31V.
Functionality Audio Tests:
9. Sweep the audio signal voltage from 15 mV
10. Monitor the output signals at P1/P3 with an oscilloscope. The waveform must be a non
distorted sinusoidal signal with input sinusoidal signal below 1Vrms.
to 1.5 V
RMS
RMS
.
Performance and Test Graphs
Power vs THD+N (without heatsink)
Test Conditions:
Load Impedance = 4 ohms
VBus = 31V
Input Signal=1 kHz
10
5
THD+N vs Power
2
1
0.5
0.2
0.1
%
0.05
0.02
0.01
0.005
0.002
0.001
20m 4050m 100m 200m 500m 1 2 5 10 20
W
ColorSweep Trace Line Style Thick Data Axis Comment
1 1 Red Solid 2 Anlr.THD+N Ratio Left Ch1 4ohms 31V
1 3 B lue Solid 2 Anlr. THD+N Ratio Left Ch2 4ohms 31V
Fig 2
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IRAUDAMP15 REV 1.0
Frequency Response
Test Conditions:
Load Impedance = 4 ohms
VBus = 31V
Set Output = 1V
+4
+2
+0
d
B
r
A
-2
-4
-6
-8
-10
20 200k50 100 200 500 1k 2k 5k 10k 20k 50k 100k
T
Hz
ColorSweep Trace Line Style Thick Data Axis Comment
1 1 Red Solid 2 A nlr.Level A Left Ch1 4ohm SP 25V
1 2 Blue Solid 2 Anlr.Level B Left Ch2 4ohm SP 25V
Noise Floor
Test Conditions:
Load Impedance = 4 ohms
No Input Signal
VBus = 31V
d
B
V
+20
+0
-20
-40
-60
-80
-100
-120
-140
10 20k20 50 100 200 500 1k 2k 5k 10k
Fig 3
Hz
ColorSweep Trace Line Sty le Thick Data Axis Comment
1 1 Red Solid 2 Fft.Ch.1 Ampl Left Ch1
1 2 B lue Solid 2 Fft.Ch.2 Ampl Left Ch2
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Fig 4
IRAUDAMP15 REV 1.0
Noise Floor with 1Vrms Output
Test Conditions:
Load Impedance = 4 ohms
VBus = 31V
Output = 1Vrms @ 1 KHz
+0
-20
-40
d
B
-60
V
-80
-100
10 20k20 50 100 200 500 1k 2k 5k 10k
Hz
Efficiency
ColorSweep Trace Line Sty le Thick Data Axis Comment
1 1 Red Solid 2 Fft.Ch.1 Ampl Left Ch1 4ohm
1 2 B lue Solid 2 Fft.Ch.2 Ampl Left Ch1 4ohm
Fig 5
100.0%
90.0%
80.0%
70.0%
60.0%
50.0%
Efficiency
40.0%
30.0%
20.0%
10.0%
0.0%
0 5 10 15 20 25 30 35 40
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Power (W )
Fig 6
IRAUDAMP15 REV 1.0
Thermal Information:
1/8 Po Thermal Test
Conditions:
Tamb=25°C natural convection cooling
Both Channel Driven 1/8Po continuous 30mins
Temperature measured by infrared camera
Fig 7 IRAUDAMP15 (Vbus=31V)
IR4311’s temperature saturated around 85°C within 30minutes
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IRAUDAMP15 REV 1.0
Schematic
+B
+B C T_PGND
2
S1
1
OFF
+B
354
18-31V Bus
Z8
16V
R59
10k
R58
47k
R55
10k
R54
10k
R53
47k
6
SW SPDT
ON
SD
CT_PGN D
R60
47k
UVP
1
2
+B
+
GND
P2
+B
GND
2200uF, 25V
2200uF, 25V
C42
C43
C39
C40
NM
NM
R51 10k, 1/2WR5210k, 1/2W
GND
18-27V 27-31V
220ohm 470 Ohm
-
+B
Power S upply
Voltage Range
R25,R26,R27,R28
*
18-31V Bus
CH1
1
2
P3
RCH
R50 2.2k
D7
D8
R48
10, 1W
CH2_ OUT
GND
CT_PGND
C38
0.1uF, 63V
GND
MMBT5551
Q4
Z7
33V
OVP
C41
0.1uF
CT_SGND CT_PGND
GND
MMBT5551
Q3
1
2
P1
LCH
CT_PGND
R49 2. 2k
D6
C37
R47
10, 1W
CH1_ OUT D5
0.1uF, 63V
L1
C35
22uH
0.47uF, 400V
C31
NM
C29
0.1uF
NM
C25
0.1uF
C23
R33
2.7K
D3
R31
4.7R
1N4148
PQFN
VP
12
D9
1N4148
U1
15
18V-31V version
47.5k 1%
47.5k 1%
R15
R16
R11
R12
C1
1nF
*3.01k 1%
R5
330
R6
CT_SGND
SCH_IR4311_Single Supply Rev2.4
CP1
Class D, AMP15 Schematic
2.2uF
R3100k
CP2
VB
13
R27
*3.01k 1%
330
CSH
14
*470R 1W
Z1
5.1V
CT_SGN D
+5V
C17
4.7uF,10V
R23
VAA1
C2
1nF
CT_SGND
2.2uF
IN+3GND2VAA
1
CT_SGND
C15
180R
R19
180R
R20 180R
C11
2.2nF,50V
2.2nF,50V
C5
FET1
Audio Gnd 1
Prot1
R1
CT_SGND
R43NM
C6
1
3
R44NM
R37
23
VS1
MJD44H11T4GQ1
11
VS
O
-B
COMP
CSD6IN-
VSS
5
4
7
1nF
C13
2.2nF,50V
C7 22uF, 16V
2.2nF,50V
SD
2
R9
1k
BS250F
D1
Red LED
4.7k
SD
INPUT GND
5
4
NM
R41
1R
470R 1W
C26
+B
R35 4.7k
Z5
11V
1
CP5
22uF
VCC
VN
10
R29
4.7R
COM
9
VCC
C21
10uF
8
R25
*470R 1W
Z3
-5V
VSS1
R36
NM
213
CN1
5.1V
CT_SGND
C19
4.7uF,10V
47.5k 1%
R17
C44
NM
R13
C3
1nF
*3.01k 1%
R7
330
CT_SGND
2.2uF
CP3
CP4
R4100k
47.5k 1%
R18
R14
R8
0.1uF
C24
R34
2.7K
D4
1N4148
PQFN
12
D10
1N4148
13
R28
14
*470R 1W
Z2
5.1V
CT_SGN D
C18
4.7uF,10V
R24
VAA2
C12
C4
1nF
*3.01k 1%
330
CT_SGND
2.2uF
L2
C36
22uH
0.47uF, 400V
C32
NM
C30
0.1uF
NM
C27
R32
4.7R
VP
U2
15
VB
CSH
IN+3GND2VAA
1
+5V
CT_SGND
C16
180R
R21
180R
R22 180R
2.2nF,50V
2.2nF,50V
C8
FET2
Audio Gnd 1
Prot2
R2
R45NM
C9
1
3
CT_SGND
R46NM
VS2
11
VS
O
-B
COMP
CSD6IN-
VSS
5
4
7
1nF
C14
2.2nF,50V
C10 22uF, 16V
2.2nF,50V
SD
2
R10
1k
BS250F
D2
Red LED
4.7k
SD
R38
NM
R42
1R
C28
DS1
R62
5.1k
VCC
VN
10
R30
4.7R
COM
9
VCC
C22
10uF
8
R26
*470R 1W
Z4
-5V
VSS2
R63
R61
R39
NM
5.1V
CT_SGND
C20
4.7uF,10V
CT_PGN DCT_PGND
10R
C45 470pF, 50V
CT_PGND CT_PGND
GND
10R
INPUT GND
NM
CT_PGND
Fig8
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IRAUDAMP15 REV 1.0
Bill of Materials
No Part Number Designator Description Quantity Vender
1 490-1494-1-ND C1, C2, C3, C4, C15, C16 CAP CER 1000PF 50V 10% X7R 0603 6 Digikey
2 445-1309-1-ND
3 587-1433-1-ND C7, C10 CAP CER 22UF 16V X5R 1206 2 Digikey
4 478-1429-1-ND C17, C18, C19, C20 CAP CER 4.7UF 10V Y5V 0805 4 Digikey
5 399-3525-1-ND C21, C22 CAP CERAMIC 10UF 16V X7R 1206 2 Digikey
6 311-1140-1-ND C23, C24, C41 CAP CER 0.1UF 50V 10% X7R 0805 3 Digikey
7 445-1418-1-ND C29, C30 CAP CER .10UF 100V X7R 10% 0805 2 Digikey
8 495-1315-ND C35, C36 CAP FILM 0.47UF 400VDC RADIAL 2 Digikey
9 BC2054-ND C37, C38 CAP FILM 0.1UF 63VDC RADIAL 2 Digikey
10 565-1064-ND C42, C43 CAP ALUM 2200UF 25V 20% RADIAL 2 Digikey
11 311-1124-1-ND C45 CAP 470PF 50V CERAMIC X7R 0805 1 Digikey
12 CP1-3545N-ND CN1 CONN JACK STEREO R/A 5PIN 3.5MM 1 Digikey
13 565-1103-ND CP1, CP2, CP3, CP4 CAP ALUM 2.2UF 50V 20% RADIAL 4 Digikey
14 565-1056-ND CP5 CAP 22UF 25V ELECT VR RADIAL 1 Digikey
15 1N4148WS-FDICT-ND D1, D2 DIODE SWITCH 75V 200MW SOD323 2 Digikey
16 1N4148WDICT-ND D3, D4, D9, D10 DIODE SWITCH 100V 400MW SOD-123 4 Digikey
17 160-1647-1-ND DS1 LED BLUE CLEAR THIN 0603 SMD 1 Digikey
18 BS250FCT-ND FET1, FET2 MOSFET P-CH 45V 90MA SOT23-3 2 Digikey
19 Sagami 7G13A-220M-R L1, L2 Class D Inductor, 22UH 13A 2
20 281-1414-ND P1, P2, P3 CONN TERM BLOCK PCB 5.0MM 2POS 3 Digikey
21 160-1182-1-ND Prot1, Prot2 LED RED ORANGE CLEAR 0603 SMD 2 Digikey
22 MJD44H11T4GOSCT-ND Q1 TRANS PWR NPN 8A 80V DPAK 1 Digikey
23 MMBT5551FSCT-ND Q3, Q4 TRANSISTOR NPN 160V SOT-23 2 Digikey
24 RMCF0603JT4K70CT-ND R1, R2 RES 4.7K OHM 1/10W 5% 0603 SMD 2 Digikey
25 RMCF0603JT100KCT-ND R3, R4 RES 100K OHM 1/10W 5% 0603 SMD 2 Digikey
26 RMCF0603JT330RCT-ND R5, R6, R7, R8 RES 330 OHM 1/10W 5% 0603 SMD 4 Digikey
27 RMCF0603JT1K00CT-ND R9, R10 RES 1K OHM 1/10W 5% 0603 SMD 2 Digikey
28 RHM3.01KCRCT-ND R11, R12, R13, R14 RES 3.01K OHM 1/8W 1% 0805 SMD 4 Digikey
29 311-47.5KCRCT-ND R15, R16, R17, R18 RES 47.5K OHM 1/8W 1% 0805 SMD 4 Digikey
30 RHM180GCT-ND R19, R20, R21, R22, R23, R24 RES 180 OHM 1/10W 5% 0603 SMD 6 Digikey
31 RMCF2512JT470RCT-ND R25, R26, R27, R28 RES 470 OHM 1W 5% 2512 SMD 4 Digikey
32 P4.7ACT-ND R29, R30, R31, R32 RESISTOR 4.7 OHM 1/8W 5% 0805 4 Digikey
33 RHM2.7KGCT-ND R33, R34 RES 2.7K OHM 1/10W 5% 0603 SMD 2 Digikey
34 RHM4.7KGCT-ND R35 RES 4.7K OHM 1/10W 5% 0603 SMD 1 Digikey
35 PT470XCT-ND R37 RES 470 OHM 1W 5% 2512 SMD 1 Digikey
36 P1.0ACT-ND R41, R42 RESISTOR 1.0 OHM 1/8W 5% 0805 2 Digikey
37 541-10.0AFCT-ND R47, R48 RES 10.0 OHM 1W 1% 2512 SMD 2 Digikey
38 RMCF0805JT2K20CT-ND R49, R50 RES 2.2K OHM 1/8W 5% 0805 SMD 2 Digikey
39 541-10KVCT-ND R51, R52 RES 10K OHM 1/2W 5% 1210 SMD 2 Digikey
40 RHM47KARCT-ND R53, R58, R60 RES 47K OHM 1/8W 5% 0805 SMD 3 Digikey
41 RHM10KARCT-ND R54, R55, R59 RES 10K OHM 1/8W 5% 0805 SMD 3 Digikey
42 311-10ARCT-ND R61, R63 RES 10 OHM 1/8W 5% 0805 SMD 1 Digikey
43 RMCF0603JT5K10CT-ND R62 RES 5.1K OHM 1/10W 5% 0603 SMD 1 Digikey
44 360-1758-ND S1
45 IR4311 U1, U2 2 CH PowIRaudio integrated Class D IC 2 IR
C5, C6, C8, C9, C11, C12, C13,
C14
CAP CER 2200PF 50V X7R 10% 0603 8 Digikey
Inductors,
Inc
SWITCH TOGGLE SPDT .4VA SEAL
PCB 1 Digikey
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IRAUDAMP15 REV 1.0
46 DDZ5V1BDICT-ND Z1, Z2, Z3, Z4 DIODE ZENER 5.1V 500MW SOD-123 4 Digikey
47 BZT52C11-FDICT-ND Z5 DIODE ZENER 11V 500MW SOD123 1 Digikey
48 568-3766-1-ND Z7 DIODE ZENER 33V 375MW SOD123F 1 Digikey
49 BZT52C16-FDICT-ND Z8 DIODE ZENER 16V 500MW SOD-123 1 Digikey
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.
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IRAUDAMP15 REV 1.0
PCB Layout
Top side:
Bottom side:
Fig 9
Note: Refer to AN1170 for footprint and board mounting details.
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Fig 10
IRAUDAMP15 REV 1.0
Revision changes descriptions
Revision Changes description Date
Rev 1.0 Released May, 11 2012
WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245 Tel: (310) 252-7105
Data and specifications subject to change without notice. 01/29/2009
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IRAUDAMP15 REV 1.0
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