On-Bright OB6211 User manual

2*20W Class-D Audio Amplifier
AUOB6211.00 1245
©On-BrightElectronics Confidential
OB_DOC_DBM_A_621100
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Subject
OB6211 Demo Board Manual Board Model: AUOB6211.00 1245
Doc. No: OB_DOC_DBM_A_621100
Description:
The OB6211 Demo Board consists of a stereo 20W, class-D, audio power amplifier completed with
a small number of external components mounted on a printed-circuit board. It can be used to
directly drive speakers with an external analog audio source as the input. The audio application of
2 channels single-ended(SE) or 1 channel bridge-tied-load(BTL) is presented. The detailed
features, block diagram, schematics, BOM, PCB layout, application notes and test data are
described.
Key Features:
Stereo 20W SE output into 4load at 26V
Mono 40W BTL output into 8load at 26V
Up to 95dB SNR
Soft power on/off and mute/unmute minimize pop noise
Revision History
Revise Date Version Reason/Issue
2012-11-01 00 First Issue

2*20W Class-D Audio Amplifier
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©On-BrightElectronics Confidential
OB_DOC_DBM_A_621100
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Index
1. Features....................................................................................................................................................3
2. Application Reference.............................................................................................................................4
2.1 Demo Board Block Diagram............................................................................................................ 4
2.1.1 2 channels single-ended application .................................................................................. 4
2.1.2 1 channel bridge-tied-load application ............................................................................... 4
2.2 Terminal & Switch & Jack ................................................................................................................ 5
2.2.1 Terminal & Switch & Jack Assignment ............................................................................... 5
2.2.2 Switch Setting..................................................................................................................... 5
2.3 Schematic........................................................................................................................................ 6
2.3.1 Demo Board Specifications ................................................................................................7
2.4 Operation......................................................................................................................................... 7
2.4.1 Quick Start List for Stand-Alone Operation ........................................................................ 7
2.4.2 Power Supply ..................................................................................................................... 7
2.4.3 Audio Inputs and Outputs................................................................................................... 7
2.4.4 Control Inputs ..................................................................................................................... 7
2.4.5 Power Up............................................................................................................................ 7
3. EMI Test Report .......................................................................................................................................8
3.1 Conducted EMI Test ........................................................................................................................ 8
3.2 Radiation EMI Test .......................................................................................................................... 8
4. Reference .................................................................................................................................................9
4.1 PCB layout ...................................................................................................................................... 9
4.2 Bill of Material.................................................................................................................................11

2*20W Class-D Audio Amplifier
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©On-BrightElectronics Confidential
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1. Features
•Stereo 20W SE output into 4load at 26V
•Mono 40W BTL output into 8load at 26V
•10V to 32V single-supply operation
•Can drive stereo speakers as low as 4
•85% efficiency(driving 4speakers)
•Up to 95dB SNR
•Low quiescent current 13mA
•Four selectable gain settings(20,26,32,36dB)
•External mute/shutdown control function
•Internal oscillator (no external components required)
•Perfect OTP/OVP/OCP/UVP protection with recovery
•Soft power on/off and mute/unmute minimize pop noise
•Eliminates the need of external heat sink
•Space-saving surface mount 28-Pin HSOP28 high power package
•Meet EN55022-ClassB , EN55014 EMI standard

2*20W Class-D Audio Amplifier
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2. Application Reference
2.1 Demo Board Block Diagram
2.1.1 2 channels single-ended application
Fig. 1 2 channels single-ended application System Block Diagram
2.1.2 1 channel bridge-tied-load application
Fig. 2 1 channel bridge-tied-load application System Block Diagram

2*20W Class-D Audio Amplifier
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©On-BrightElectronics Confidential
OB_DOC_DBM_A_621100
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2.2 Terminal & Switch & Jack
2.2.1 Terminal & Switch & Jack Assignment
Reference Number I/O Description
VCC I Power Supply (10 – 32VDC)
GND I
Power Supply ground
LIN I Audio input for left channel (SE) / Audio input for BTL+
RIN I
Audio input for right channel (SE) / Audio input for BTL-
LGND O
Audio output ground for left channel of SE connection
LOUT O
Audio output for left channel of SE connection
RGND O
Audio output ground for right channel of SE connection
ROUT O
Audio output for right channel of SE connection
BTL+ O
Audio output positive pole for BTL connection
BTL- O
Audio output negative pole for BTL connection
S -
Shutdown control switch
S1
M -
Mute control switch
G1 -
Gain select most-significant bit.
S2
G0 -
Gain select least-significant bit.
* About the Terminal&Switch&Jack’s position on demo board, please refer to the 4.1 PCB layout ‘s
component view. Table 1. Terminal & Switch & Jack Assignment
2.2.2 Switch Setting
*Note1: Gain select setting
GAIN G1 G0
20dB ON ON
26dB ON OFF
32dB OFF ON
36dB OFF OFF
Gain G1@S2 G0@S2
20dB ON ON
26dB ON OFF
32dB OFF ON
36dB OFF OFF
Table 2. Gain select setting
Action Switch
MUTE ON
UNMUTE
M@S1
OFF
SHUTDOWN ON
ACTIVE
S@S1
OFF
Table 3. mute and shutdown setting

2*20W Class-D Audio Amplifier
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©On-BrightElectronics Confidential
OB_DOC_DBM_A_621100
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2.3 Schematic

2*20W Class-D Audio Amplifier
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2.3.1 Demo Board Specifications
Symbol Item Specification
Vcc Supply Voltage range 10 V to 32 V
Icc Supply current 4 A max
Continuous output power per channel: 4 , VCC = 26 V, THD+N = 10%,SE 20 W
Po Continuous output power per channel: 8 , VCC = 26 V, THD+N = 10%,BTL 40W
RL Minimum load impedance 4 
Vin Input amplitude range 0~2Vrms
2.4 Operation
2.4.1 Quick Start List for Stand-Alone Operation
Follow these steps to use the OB6211 demo board stand-alone or when connecting it into existing circuits
or equipment. Connections to the demo board can be made by inserting stripped wire or using banana
plugs for the power supply and output connections. The audio inputs accept standard RCA plugs.
2.4.2 Power Supply
1. Ensure that all external power sources are set to OFF.
2. Connect an external regulated power supply adjusted from 10 V to 32 V to the POWER connector with
taking care to observe marked polarity.
2.4.3 Audio Inputs and Outputs
1. Connect a speaker across terminals LGND and LOUT. Connect another speaker across terminals
ROUT and RGND.
2. Connect an analog audio source to jacks LIN and RIN using standard RCA phono plugs.
2.4.4 Control Inputs
1. SHUTDOWN: This function is active LOW. A LOW (<0.8 V) on this device pin shuts down the amplifier;
a HIGH (>2 V) places the amplifier in the active state. Setting S(@S1) to ON places the amplifier in the
shutdown state. Setting back S(@S1) returns the amplifier to the active state. This pin is Vcc compliant.
2. MUTE: This function is active HIGH. A HIGH (>2 V) on this device pin places the amplifier in the mute
state, the outputs remain switching with 50% duty cycle; a LOW (<0.8 V) enables the sound output.
Setting M(@S1) to ON places the amplifier in the mute state. Setting back M(@S1) returns the amplifier
to the unmute state. This pin is Vcc compliant.
3. GAIN0/GAIN1: Together, these switchs determine the gain of the amplifier. Setting G1(@S2) or
G0(@S2) to ON connects the respective pin to GND. Setting G1(@S2) or G0(@S2) to OFF connects
the respective pin to VCC. Logic levels are TTL compatible. These pins are Vcc compliant. For gain
setting, please refer to Table2. Gain select setting
2.4.5 Power Up
1. Verify correct voltage and input polarity, and turn the external power supplies ON. The demo board
begins operation
2. Adjust the input signal.
3. Adjust the control inputs to the desired settings.
4. Adjust the amplifier gain by S2.
* For mono BTL application, please open the FB1 and FB2 first. Then connect a speaker across BTL+ and
BTL- that marked on PCB. Then conduct above steps.

2*20W Class-D Audio Amplifier
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3. EMI Test Report
The demo board passed EMI requirement with more than 6dB margin
3.1 Conducted EMI Test
EN55014 @ 5W4ohm report
3.2 Radiation EMI Test
EN55022 CLASS B @ 5W4ohm report,(speaker cable length 50cm)

2*20W Class-D Audio Amplifier
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©On-BrightElectronics Confidential
OB_DOC_DBM_A_621100
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4. Reference
4.1 PCB layout
TOP Component View
Bottom Component View

2*20W Class-D Audio Amplifier
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Top Copper View
Bottom Copper View

2*20W Class-D Audio Amplifier
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4.2 Bill of Material
No. EVM Ref.No. Description Load
Status Size QTY. MFG Part No.
Resistor:
1 R1,R2 Resistor,chip,0ohm,1/10W,5% 0805 2
2 R3,R4, R5,R6 Resistor,chip,10kohm,1/10W,5% 0805 4
3 R7, R9 Resistor,chip,4.7kohm,1/10W,5% 0805 2
4 R8 Resistor,chip,0ohm,1/2W,5% 1210 1
5 FB1,FB2,FB3,FB4 Resistor,chip,0ohm,1/2W,5% 1210 4
Capacitor:
6 C1,C8 Capacitor,electrolytic,470uF,50V,105℃,lo
w impedance Φ5*12.5 2
7 C2,C7,C13 Capacitor,ceramic,0.1uF,±10%,X7R,50V 0805 3
8 C3,C4,C5, Capacitor,ceramic,1.0uF,±10%,X7R,16V 0805 3
9 C6 Capacitor,ceramic,2.2uF,±10%,X7R,16V 0805 1
10 C9,C16 Capacitor,ceramic,0.47uF,±10%,X7R,50V 0805 2
11 C10,C17 Capacitor, CBB,0.68uF,63V Radial 2
10 C11,C18 Capacitor,ceramic,0.22uF,±10%,X7R,50V NC
12 C12,C19 Capacitor,electrolytic,1000uF,50V,105℃,
low ESR Φ7.5*18 2
13 C14 Capacitor,ceramic,10uF,+80%--20%,X7R,
50V 1210 1
14 C15 Capacitor,electrolytic,220uF,50V,85℃,Ge
neral Purpose NC
Inductor：
15 L1,L2 Inductor,22uH,radial lead, ferrite material,
shielded Radial 2
Jack&Switcher&Therminal:
16 LOUT,LGND,ROU
T,RGND Banana Jack 4
17 CON1 Power Connector,2pin,7.9mmpitch 1
18 PLUG Power Plug,2pin,7.9mmpitch 1
19 LIN Phono Jack, PC mount, switched, red 1
20 RIN Phono Jack, PC mount, switched, white 1
21 S1,S2 DIP SWITCH,2channel 2
22
BTL+,BTL-,GATE
_L,GATE_R,GND,
GNDL,GNDR
OUTL,OUTR,VCC
Test Point Connector,red,1.32mm type NC
PCB:
23 PCB OB6211 EVM PCB, double layer 82*71*1.6 1 AUOB6211.
00 1245
ICs:
24 U1 audio amplifier HSOP28 1 OB6211
* For different speaker impendence application, recommended L1,L2,C10,C17,C12,C19 value, please refer
to datasheet.
* All components should be ordered as Lead-Free

2*20W Class-D Audio Amplifier
AUOB6211.00 1245
©On-BrightElectronics Confidential
OB_DOC_DBM_A_621100
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Disclaimer
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and other changes to its documents, products and services at any time and to discontinue any product or
service without notice. Customers should obtain the latest relevant information before placing orders and
should verify that such information is current and complete.
This document is under copy right protection. Non of any part of document could be reproduced, modified
without prior written approval from On-Bright Electronics.