Eval Board

IS31AP2145A 2.9W@5V MONO CLIP-LESS & FILTER-LESS CLASS-D
AUDIO POWER AMPLIFIER
DESCRIPTION
RECOMMENDED EQUIPMENT
The IS31AP2145A is a [email protected] mono, clip-less,
filter-less, high efficiency Class-D audio power
amplifier with automatic gain control.
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The IS31AP2145A integrates an AGC (Automatic Gain
Control) function to automatically prevent distortion of
the audio signal by which we can enhance audio
quality and also protect the speaker from damage at
high power levels. The AGC function and its attack
time/release time are selectable via the CTRL pin. The
IS31AP2145A also provides thermal and over current
protection functions.
The demo board has four modes (AGC1, AGC2, AGC
OFF, and SHUTDOWN) to test the functionality of the
IS31AP2145A.
FEATURES
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Operating from VCC = 2.7V ~ 5.5V
Filter-less Class-D architecture
AGC enable/disable function
2.7W into 4Ω at 5.0V (10% THD+N)
Minimum external components
High efficiency: 90%
Click-and-pop suppression
Short-circuit and thermal protection
Space-saving UTQFN-9, 1.5mm × 1.5mm
5.0V, 2A power supply
Audio source (i.e. MP3 player, Notebook PC, etc.)
8Ω or 4Ω speakers
ABSOLUTE MAXIMUM RATINGS

≤ 5.5V power supply
Caution: Do not exceed the conditions listed above, otherwise
the board will be damaged.
PROCEDURE
The IS31AP2145A demo board is fully assembled and
tested. Follow the steps below to verify board
operation.
Caution: Do not turn on the power supply until all connections
are completed.
1)
2)
3)
QUICK START
4)
Connect a 4Ω (or larger) speaker across the OUTterminal and OUT+ terminal or the RCA female
connector (SPK CON3).
Connect the ground terminal of the power supply
to the GND (TP2) and the positive terminal to the
VCC (TP1). Or connect DC power to connector
(DC IN) with a 2.5 mm jack.
If the audio source is differential, remove jumper
JP1, connect the negative of the audio source to
the IN- terminal, and connect the positive of the
audio source to IN+ terminal.
If the audio source is single-ended, connect the
audio source to the IN+ terminal, and close
jumper JP1; or connect audio source to the audio
mono connector (AUDIO IN) and close jumper
JP1.
Turn on the power supply, and pay attention to the
supply current. If it is over 1.5A, turn off power and
check the evaluation board for short circuit
connections.
Figure 1: Photo of IS31AP2145A Evaluation Board
ORDERING INFORMATION
Part No.
Temperature Range
Package
IS31AP2145A-UTLS2-EB
-40°C ~ +85°C (Industrial)
UTQFN-9, Lead-free
Table 1: Ordering Information
For pricing, delivery, and ordering information, please contact ISSI’s analog marketing team at
[email protected] or (408) 969-6600.
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 01/13/2015
1
IS31AP2145A 2.9W@5V MONO CLIP-LESS & FILTER-LESS CLASS-D
AUDIO POWER AMPLIFIER
EVALUATION BOARD OPERATION
HIGH-PASS FILTER
The IS31AP2145A demo board has an LPC922 MCU
to read the status of the four buttons which select
between the different modes shown in Table Co1
below. The current operating mode is indicated by the
illuminated LED above the appropriate button. The
default mode is AGC1 enabled.
The evaluation board’s high-pass filter consists of the
input capacitors CIN (C4 or C5) and RIN (IS31AP2145A
internal resistance (28.5kΩ) + (R1 or R2). The filter’s
corner frequency, fC, is determined by Equation (1).
1
f 
c 2R C 
IN IN
Table 2 Mode settings
The corner frequency can be adjusted by replacing the
R1 or R2 0Ω resistors with a larger resistor value or by
increasing/decreasing the C4 or C5 capacitance.
CTRL1
CTRL2
Mode
H
H
AGC1
H
GND
AGC2
GND
H
AGC OFF
GND
GND
Shutdown
See the IS31AP2145A
configuration details.
datasheet
(1)
for
SHUTDOWN MODE
The SHUTDOWN button selects the power-down
mode of the IS31AP2145A.
mode
Note: The IS31AP2145A Mode setting is controlled by the
onboard LPC922 MCU.
TP1
C2
1uF
C3
0.1uF
10nF R1
0R
A1
IN+
B2
TP4
10nF R2
OUT+
0R
C1
SPK
C11
SHUTDOWN
K4
3
20
8
9
10
5
P0.4
P1.7
P0.5
P0.0
VDD
P0.1
P0.6
INT1/P1.4
T1/P0.7
INT0/P1.3
T0/P1.2 TXD/P1.0
GND
RXD/P1.1
GND
18
R11
1K
D2
17
3V
U2
C8
1uF
C9
16
0.1uF
15
14
R12
1K
D3
13
R13
1K
D4
12
11
VCC
C7
10nF
4
D1
BP
P1.6
1K
EN
P0.3
R10
GND
2
OSC1
3V
19
Vdd Vout
1
P0.2
4
3
AGC OFF
K3
6
OSC2
IS31AP2145A
1
AGC2
K2
7
Speaker
TP6
VCC
RST
R6 R7 R8 R9
10K 10K 10K 10K
C3 OUT-
0.1uF
U3
3V
AGC1
CTRL
33K
R4
R5
22K
K1
C2
SD
GND
68K
B3
CTRL2
R3
OUT-
B1
CTRL1
CLOSE=SE
CON3
IN-
TP7
JP1
TP5
A3 OUT+
2
C5
IN+
U1
VREF
C4
1uF
VDD
TP2
IN-
C10
A2
C1
10uF
TP3
CON2
AUDIO IN
VCC
VCC
5
CON1
DC IN
PAM3101
C6
1uF
CTRL2
CTRL1
LPC922
Figure 2: IS31AP2145A Application Schematic
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 01/13/2015
2
IS31AP2145A 2.9W@5V MONO CLIP-LESS & FILTER-LESS CLASS-D
AUDIO POWER AMPLIFIER
BILL OF MATERIALS
Name
Symbol
Amplifier
U1
LDO
Description
Qty
Supplier
Part No.
Class-D audio amplifier
1
ISSI
IS31AP2145A-UTLS2
U2
Low-dropout regulator
1
PAM
PAM3101
MCU
U3
Microcontroller
1
NXP
LPC922
LED
D1~D4
LEDs Blue, SMD
4
Everlight
19-217/BHC-ZL1M2RY/3T
Resistor
R1, R2
RES,0R,1/16W,±5%,SMD
2
Yageo
RL0603FR-0700KL
Resistor
R3
RES,68K,1/16W,±1%,SMD
1
Yageo
RC0603FR-0768KL
Resistor
R4
RES,33K,1/16W,±1%,SMD
1
Yageo
RC0603FR-0733KL
Resistor
R5
RES,22K,1/16W,±1%,SMD
1
Yageo
RC0603FR-0722KL
Resistor
R6~R9
RES,10K,1/16W,±5%,SMD
4
Yageo
RC0603JR-0710KL
Resistor
R10~R13
RES,1K,1/16W,±5%,SMD
4
Yageo
RC0603JR-071KL
Capacitor
C1
CAP,10µF,10V,±10%,SMD
1
Yageo
CC0805KRX7R6BB106
Capacitor
C2, C10
CAP,1µF,50V,±10%,SMD
2
Yageo
CC0603KRX7R9BB105
Capacitor
C3, C9,C11
CAP,0.1µF,50V,±10%,SMD
3
Yageo
CC0603KRX7R9BB104
Capacitor
C4, C5, C7
CAP,10nF,50V,±10%,SMD
3
Yageo
CC0603KRX7R9BB103
Capacitor
C6, C8
CAP,1µF,25V,±10%,SMD
2
Yageo
CC0805KRX7R8BB105
Button
K1~K4
Button SMD
4
Connector
DC IN
2.5mm DC connector
1
Connector
SPK
RCA type plugs
1
Connector
AUDIO IN
3.5mm min plug
1
TP1~TP7
TP1~TP7
Test pins
7
Bill of materials refers to Figure 2 above.
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 01/13/2015
3
IS31AP2145A 2.9W@5V MONO CLIP-LESS & FILTER-LESS CLASS-D
AUDIO POWER AMPLIFIER
0
0
2
1
2
2
1
2
1
2
2
1
2
1
2
1
2
1
2
2
2
1
0
0
Figure 3: Board Component Placement Guide - Top Layer
Figure 4: Board PCB Layout - Top Layer
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 01/13/2015
4
IS31AP2145A 2.9W@5V MONO CLIP-LESS & FILTER-LESS CLASS-D
AUDIO POWER AMPLIFIER
0
0
2
2
1
0
0
0
0
1
0
0
2
1
0
0
0
0
1
0
0
0
0
1
0
0
0
0
0
0
2
1
0
0
0
0
1
0
0
0
0
0
2
1
2
1
0
1
2
2
2
1
0
0
Figure 5: Board Component Placement Guide - Bottom Layer
Figure 6: Board PCB Layout - Bottom Layer
Copyright © 2015 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification and its products at any time without notice. ISSI assumes no liability arising out of the application or use of any information, products or services described herein. Customers are advised to obtain the latest version of this device specification before relying on any published information and before placing orders for products. Integrated Silicon Solution, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless Integrated Silicon Solution, Inc. receives written assurance to its satisfaction, that: a.) the risk of injury or damage has been minimized; b.) the user assume all such risks; and c.) potential liability of Integrated Silicon Solution, Inc is adequately protected under the circumstances Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 01/13/2015
5