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IRAUDAMP15 REV 1.0
IRAUDAMP15
35W/4Ω x 2 Channel Class D Audio Power Amplifier
Using the IR4311
By
Jun Honda, Liwei Zheng
CAUTION:
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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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* Single power supply;
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 IHF-A weighted, AES-17 filter
Channel Efficiency 96% Single-channel driven, 35W, Class D
stage
*Power Supply Voltage Range 18~27V 27~37V
*R25~R28 220Ω 470Ω
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IRAUDAMP15 REV 1.0
Connection Setup
Fig 1 Typical Test Setup
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
100W, Non-inductive Resistors
CN1
P1 P3
P2
CH1
Output CH2
Output
Audio
Input
18-31V, 3A DC supply
4 Ohm 4 Ohm
Audio Signal Generator
IR4311
SW1
SW1:PWM Shutdown/MUTE
Power
Indicator
FAULT
Indicator
FAULT
Indicator
IR4311
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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 mVRMS to 1.5 VRMS.
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.
Performance and Test Graphs
Power vs THD+N (without heatsink)
Test Conditions:
VBus = 31V
Input Signal=1 kHz
Load Impedance = 4 ohms
ColorSweep Trace Line Style Thick Data Axis Comment
1 1 Red Solid 2 Anlr.THD+N Ratio Left Ch1 4ohms 31V
1 3 Blue Solid 2 Anlr.THD+N Ratio Left Ch2 4ohms 31V
0.001
10
0.002
0.005
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
%
20m 4050m 100m 200m 500m 1 2 5 10 20
W
THD+N vs Power
Fig 2
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IRAUDAMP15 REV 1.0
Frequency Response
Test Conditions:
VBus = 31V
Set Output = 1V
Load Impedance = 4 ohms
ColorSweep Trace Line Style Thick Data Axis Comment
1 1 Red Solid 2 Anlr.Level A Left Ch1 4ohm SP 25V
1 2 Blue Solid 2 Anlr.Level B Left Ch2 4ohm SP 25V
-10
+4
-8
-6
-4
-2
+0
+2
d
B
r
A
20 200k50 100 200 500 1k 2k 5k 10k 20k 50k 100k
Hz
T
Noise Floor
Test Conditions:
VBus = 31V
Load Impedance = 4 ohms
No Input Signal
ColorSweep Trace Line Style Thick Data Axis Comment
1 1 Red Solid 2 Fft.Ch.1 Ampl Left Ch1
1 2 Blue Solid 2 Fft.Ch.2 Ampl Left Ch2
-140
+20
-120
-100
-80
-60
-40
-20
+0
d
B
V
10 20k20 50 100 200 500 1k 2k 5k 10k
Hz
Fig 3
Fig 4
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IRAUDAMP15 REV 1.0
Noise Floor with 1Vrms Output
Test Conditions:
VBus = 31V
Output = 1Vrms @ 1 KHz
Load Impedance = 4 ohms
ColorSweep Trace Line Style Thick Data Axis Comment
1 1 Red Solid 2 Fft.Ch.1 Ampl Left Ch1 4ohm
1 2 Blue Solid 2 Fft.Ch.2 Ampl Left Ch1 4ohm
-100
+0
-80
-60
-40
-20
d
B
V
10 20k20 50 100 200 500 1k 2k 5k 10k
Hz
Efficiency
0.0%
10.0%
20.0%
30.0%
40.0%
50.0%
60.0%
70.0%
80.0%
90.0%
100.0%
0 5 10 15 20 25 30 35 40
Power (W)
Efficiency
Fig 5
Fig 6
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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
Fig8
D1 R9
1k
+B
GND
SD
VCC
R31
4.7R
IN+
3
GND
2
VAA
1
VB 13
VP 12
COMP
5
VN
10
VS 11
VCC
8
CSD
6
IN-
4
VSS
7
COM
9
CSH 14
O
15
U1
PQFN
C15
1nF
18-31V Bus
+5V
-5V
Audio Gnd 1
SD
C21
10uF
0.1uF
C23
Class D, AMP15 Schematic
SCH_IR4311_Single Supply Rev2.4
C6
2.2nF,50V
C13
2.2nF,50V
C7 22uF, 16V
C17
4.7uF,10V
C19
4.7uF,10V
D3
1N4148
R29
4.7R
R20 180R
-B
R33
2.7K
C42
2200uF, 25V
R51 10k, 1/2WR5210k, 1/2W
C39
NM
C26
NM
VS1
L1
22uH
R49 2.2k
R47
10, 1W
C35
0.47uF, 400V
+
-
LCH
CH1_OUT D5
R44NM
C25
NM
C40
NM
R43NM
Z1
5.1V
CT_PGND
CT_SGND
Z3
5.1V
CT_SGND
R3100k
R5
330 C1
1nF
R6
330 C2
1nF
R11
*3.01k 1%
R12
*3.01k 1%
CT_SGND
CT_SGND
CT_SGND
C5
2.2nF,50V
C11
2.2nF,50V
R19
180R
R23
180R
R1
4.7k
Prot1
Red LED
CT_SGND
R55
10k
R53
47k
R54
10k R58
47k
R59
10k
R60
47k
12
3
54
6
S1
SW SPDT
C41
0.1uF
Q3
MMBT5551
Q4
MMBT5551
+B
SD
OVP
UVP
+B CT_PGND
+B
GND
VSS1
C29
0.1uF
R41
1R
C31
NM
D2
+B
GND
SD
VCC
R32
4.7R
IN+
3
GND
2
VAA
1
VB 13
VP 12
COMP
5
VN
10
VS 11
VCC
8
CSD
6
IN-
4
VSS
7
COM
9
CSH 14
O
15
U2
PQFN
C16
1nF
18-31V Bus
+5V
-5V
Audio Gnd 1
SD
C22
10uF
0.1uF
C24
C9
2.2nF,50V
C14
2.2nF,50V
C10 22uF, 16V
C18
4.7uF,10V
C20
4.7uF,10V
D4
1N4148
R30
4.7R
R22 180R
-B
R34
2.7K
C28
NM
VS2
L2
22uH
R50 2.2k
R48
10, 1W
C36
0.47uF, 400V
RCH
CH2_OUT
R46NM
C27
NM
R45NM
CT_PGND
CT_SGND
CT_SGND
R4100k
R7
330 C3
1nF
R8
330 C4
1nF
R13
*3.01k 1%
R14
*3.01k 1%
CT_SGND
CT_SGND
CT_SGND
C8
2.2nF,50V
C12
2.2nF,50V
R21
180R
R24
180R
R2
4.7k
Prot2
Red LED
CT_SGND
VSS2
C30
0.1uF
R42
1R
C32
NM
3
2
1
FET2
BS250F
3
2
1
FET1
BS250F
18V-31V version
GND
GND
C44
NM
R36
NM
2
1
3
5
4
CN1
R37
470R 1W
1
23 MJD44H11T4GQ1
R35 4.7k
Z5
11V
CP5
22uF
+B
C43
2200uF, 25V
1
2
P3
+B
GND
CH1
1
2
P1
1
2
P2
C38
0.1uF, 63V
D6
D7
D8
OFF
ON
VAA2
VAA1
CT_SGND CT_PGND
INPUT GND
INPUT GND
R61
10R
R62
5.1k
DS1
CT_PGND
CT_PGND
D9
1N4148
D10
1N4148
C45 470pF, 50V
GND
CP1
2.2uF
C37
0.1uF, 63V
R63
10R
CT_PGND CT_PGND
CT_PGNDCT_PGND
Z2
5.1V
Z4
5.1V
R39
NM
Z8
16V
Z7
33V
CP2
2.2uF
CP3
2.2uF
CP4
2.2uF
R27
*470R 1W
R25
*470R 1W
R28
*470R 1W
R26
*470R 1W
R15 47.5k 1%
R16 47.5k 1%
R17 47.5k 1%
R18 47.5k 1%
R38
NM
R10
1k
Powe r S upply
V oltage Range
220ohm 470 O hm
18-27V 27-31V
R25,R26,R27,R28
*
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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
C5, C6, C8, C9, C11, C12, C13,
C14 CAP CER 2200PF 50V X7R 10% 0603 8 Digikey
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
Inductors,
Inc
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
SWITCH TOGGLE SPDT .4VA SEAL
PCB 1 Digikey
45 IR4311 U1, U2 2 CH PowIRaudio integrated Class D IC 2 IR
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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:
Fig 9
Bottom side:
Note: Refer to AN1170 for footprint and board mounting details.
Fig 10
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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
