PAM8945

PAM8945
4.0W CLASS-G AUDIO AMPLIFIER WITH INTEGRATED
BOOST CONVERTER AND BATTERY TRACKING AGC
Description
Pin Assignments
(Top View)
NEW PRODUCT
The PAM8945 is a high efficiency Class-G audio power
amplifier with an integrated boost converter. It drives up to
4.0W (10% THD+N) into a 4Ω speaker. With 85% typical
efficiency, the PAM8945 helps extend battery life when
playing audio.
The built-in boost converter generates the voltage rail for the
output stage. This provides a louder audio output than a
stand-alone amplifier connected directly to the battery. It also
maintains a consistent loudness, regardless of battery
voltage.
The PAM8945 features battery tracking AGC function which
adjusts the amplifier gain to limit battery current at lower
battery voltage.
BGND
SW
12
11
PVDD
1
10
VBAT
OUT+
2
9
AGC
OUT-
3
8
EN
PGND
4
7
IN+
The PAM8945 features DC input protection and all outputs
are fully protected against output-to-output shorts. The
PAM8945 is available in tiny W-QFN3020-12 package.
5
5
6
6
AGND
IN-
5
5
W-QFN3020-12
Features













Built-In Battery Tracking Automatic Gain Control (AGC)
High Efficiency Integrated Boost Converter Over 85%
4.0W into a 4Ω Load at 10% THD
3.2W into a 4Ω Load at 1% THD
Operates from 2.8V to 5.2V
Efficient Class-G Prolongs Battery Life
Minimized ON/OFF Pop Noise
Superior Low Noise
High PSRR
DC Input Protection
Auto-Recovery Short-Circuit Protection
Thermal Shutdown
Available in 2.0mm X 3.0mm 12L W-QFN Package


Totally Lead-Free & Fully RoHS Compliant (Notes 1& 2)
Halogen and Antimony Free. “Green” Device (Note 3)
Notes:
Applications





Cell Phones
PDA
GPS
Portable Electronics
Speakers
1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green"
and Lead-free.
3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and
<1000ppm antimony compounds.
PAM8945
Document number: DS38267 Rev. 1 - 2
1 of 9
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© Diodes Incorporated
PAM8945
Typical Applications Circuit
2.2μH
2.8V to 5.2V
100μF
+ 10μF
1μF
VBAT
10μF
SW PVDD
PGND
ON
NEW PRODUCT
OFF
EN
OUT+
IN+
Audio Input
IN-
AGC
AGC AGND
OUTBGND
Pin Descriptions
Pin Number
Pin Name
Description
1
PVDD
Boost Converter Output and Amplifier Power Supply
2
OUT+
Amplifier Positive Audio Output
3
OUT-
Amplifier Negative Audio Output
4
PGND
Power Ground
5
AGND
Analog Ground
6
IN-
Negative Audio Input
7
IN+
Positive Audio Input
8
EN
Shutdown Terminal for the Chip
9
AGC
AGC Setting Gain
10
VBAT
Supply Voltage
11
SW
12
BGND
PAM8945
Document number: DS38267 Rev. 1 - 2
Boost Convertor Switching
Power Ground
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PAM8945
Functional Block Diagram
V BAT
EN
Bias
SW
IN+
+
NEW PRODUCT
PVDD
Boos t Conv ertor
PWM
Modulator
AGC
-
IN-
Gate
Driv e
OUT+
Gate
Driv e
OUT-
SCP
OTP
DCP
UVLO
AGC
VREF
Startup
Protec tion
OSC
AGND
BGND
PGND
Absolute Maximum Ratings (@TA = +25°C, unless otherwise specified.)
Symbol
VBAT
Parameter
Value
Unit
Supply Voltage
-0.3 to 6.0
V
-0.3 to VBAT + 0.3
V
VI
Input Voltage, EN, IN+, IN-, AGC
TA
Operating Free-air Temperature Range
-40 to +85
°C
TJ
Operating Junction Temperature Range
-40 to +150
°C
Storage Temperature Range
-65 to +150
°C
TSTG
Recommended Operating Conditions (@TA = +25°C, unless otherwise specified.)
Symbol
Parameter
Min
Supply Voltage
Max
Unit
2.8
5.2
V
VIH
High-Level Input Voltage
EN
1.3
VBAT
V
VIL
Low-Level Input Voltage
EN
GND
0.6
V
TA
Operating Free-Air Temperature
-40
+85
°C
VBAT
Thermal Information
Symbol
Parameter
Package
Max
θJA
Thermal Resistance (Junction to Ambient)
W-QFN3020-12
62
θJc
Thermal Resistance (Junction to Case)
W-QFN3020-12
11
PAM8945
Document number: DS38267 Rev. 1 - 2
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Unit
°C/W
December 2015
© Diodes Incorporated
PAM8945
Electrical Characteristics (@VBAT=3.6V, AGC=GND, TA = +25°C, RL=4Ω +33uH, unless otherwise specified.)
Symbol
VBAT
NEW PRODUCT
PO
Parameter
Supply Voltage
Output Power
Test Conditions
Min
Typ
Max
Unit
—
2.8
—
5.2
V
THD+N=10%, f=1kHz
—
4.0
—
W
—
3.2
—
W
—
0.07
—
—
0.15
—
f=217Hz
—
70
—
f=1kHz
—
70
—
THD+N=1%, f=1kHz
VBAT=3.6V
THD+N
Total Harmonic
Distortion Plus
Noise
PO=1.0W, RL=8Ω
PSRR
Power Supply Ripple
Rejection
VBAT=3.6V, Input AC ground with C=1μF
f=10kHz
—
67
—
SNR
Signal-To-Noise Ratio
A-weighting
THD+N=1%
—
95
—
dB
VOP
Peak Output Voltage
Boost Convertor Auto-Pass
Through Threshold
VBAT=3.6V
f=1kHz
—
5.75
—
V
—
—
—
2
—
V(PEAK)
Output Noise
Input AC-ground
No A-weighting
—
100
—
A-weighting
—
60
—
η
Efficiency
RL=8Ω, PO=1W
f=1kHz
—
86
—
%
IQ
Quiescent Current
VBAT=3.6V
No Load
—
4
—
mA
ISD
Shutdown Current
VBAT=2.8V to 5.2V
EN=0V
—
—
1
μA
Static Drain-to-Source OnState Resistor
High Side PMOS,
I=500mA
Low Side NMOS,
I=500mA
VBAT=5V
—
260
—
mΩ
VBAT=5V
—
160
—
mΩ
Boost
—
1200
—
Switching Frequency
VBAT=2.8V to 5.2V
Class D
—
300
—
VO_TH
VN
RDS(ON)
fSW
PO=2W, RL=4Ω
f=1kHz
%
dB
μV
kHz
GV
Closed-Loop Gain
—
—
—
20
—
dB
RIN
Input Impedance
Av=20dB
—
—
24
—
KΩ
VOS
Output Offset Voltage
Input AC-ground
—
—
—
20
mV
IPEAK
Convertor SW Peak Current
VBAT=3.6V
—
—
4
—
A
tON
Start-Up Time From EN
—
—
—
6
—
ms
VIH
En Input High Voltage
VBAT=5V
—
1.3
—
—
VIL
En Input Low Voltage
VBAT=5V
—
—
—
0.6
PAM8945
Document number: DS38267 Rev. 1 - 2
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V
December 2015
© Diodes Incorporated
PAM8945
Performance Characteristics (@VBAT=3.6V, AGC=GND, TA = +25°C, RL=8Ω +33μH, unless otherwise specified.)
THD+N vs. Output Power (RL= 8Ω)
THD+N vs. Output Power (RL = 4Ω)
20
20
10
10
f=100Hz/1kHz/10kHz
(Red/Pink/Blue)
5
2
2
NEW PRODUCT
1
%
f=100Hz/1kHz/10kHz
(Red/Pink/Blue)
5
1
0.5
0.5
%
0.2
0.2
0.1
0.1
0.05
0.05
0.02
0.02
0.01
1m
2m
5m
10m
20m
50m
100m
200m
500m
1
2
0.01
1m
4
2m
5m
10m
20m
50m
W
200m
500m
1
2
5
8
W
THD+N vs. Frequency (RL = 8Ω)
THD+N vs. Frequency (RL = 4Ω)
10
10
Po=0.3W/0.5W/1W
(Red/Pink/Blue)
5
Po=0.3W/0.5W/1W
(Red/Pink/Blue)
5
2
2
1
%
100m
1
0.5
%
0.2
0.5
0.2
0.1
0.1
0.05
0.05
0.03
20
50
100
200
500
1k
2k
5k
10k
0.03
20
20k
Hz
50
100
200
500
1k
2k
5k
10k
20k
Hz
PSRR vs. Frequency (RL = 8Ω)
+0
TT TT TT TTT
PSRR vs. Frequency (RL = 4Ω)
+0
TT
TT TT TT TTT TT T
-10
-10
AGC=GND
-20
-20
-30
-30
-40
-40
-50
d
B
-50
d
B
-60
-60
-70
-70
-80
-80
-90
-90
-100
-100
-110
20
AGC=GND
50
100
200
500
1k
2k
5k
10k
20k
Hz
PAM8945
Document number: DS38267 Rev. 1 - 2
-110
20
50
100
200
500
1k
2k
5k
10k
20k
Hz
5 of 9
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December 2015
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PAM8945
Performance Characteristics (@VBAT=3.6V, AGC=GND, TA = +25°C, RL=8Ω +33μH, unless otherwise specified.)
Noise Floor (RL =8Ω)
Gain vs. Supply Voltage
+0
-10
-20
-30
NEW PRODUCT
-40
d
B
r
-50
A
-70
-60
-80
AGC=Float/GND/VBAT
(Red /Blue/Green)
-90
-100
-110
-120
20
50
100
200
500
1k
2k
5k
10k
20k
Hz
Efficiency vs. Output Power (RL =8Ω)
Quiescent Current vs. Supply Voltage
Start Up
PAM8945
Document number: DS38267 Rev. 1 - 2
Shutdown
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PAM8945
Ordering Information (Note 4)
PAM8945 X X X
NEW PRODUCT
Pin Configuration
P: 12 Pin
Note:
Package
Packing
J: W-QFN3020-12
R: Tape & Reel
7” Tape and Reel
Part Number
Package
PAM8945PJR
W-QFN3020-12
Quantity
Part Number Suffix
3000/Tape & Reel
-7
4. For packaging details, go to our website at http://www.diodes.com/products/packages.html.
Marking Information
W-QFN3020-12
(Top View)
P8945: Product Code
X: Internal Code
Y: Year 0~9
W: Week: A~Z: 1~26 weeks;
a~z: 27~52 weeks; z
represents 52 and 53 weeks.
PAM8945
Document number: DS38267 Rev. 1 - 2
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PAM8945
Package Outline Dimensions
Please see AP02002 at http://www.diodes.com/datasheets/ap02002.pdf for the latest version.
W-QFN3020-12
E
L1
L
PIN#1 ID
NEW PRODUCT
L2
b
e
D
e1
b1
A
A
b
A3
W-QFN3020-12
Dim
Min
Max
Typ
A
0.700 0.800
A1
0
0.05
A3
0.203REF
b
0.200 0.300
b1
0.350 0.450
D
1.900 2.100 2.000
E
2.900 3.100 3.000
e
0.500
e1
0.575
L
0.350 0.450
L1
0.450 0.550
L2
0.750 0.850
All Dimensions in mm
Suggested Pad Layout
Please see AP02001 at http://www.diodes.com/datasheets/ap02001.pdf for the latest version.
W-QFN3020-12
X1
X
Dimensions
Y
C
Y2
Y4
C1
Y1
Y3
C
G
X
X1
X2
X3
Y
Y1
Y2
Y3
Y4
Value
(in mm)
0.500
0.575
0.650
0.750
0.350
2.400
0.300
0.450
0.900
1.050
3.400
X2
X3
PAM8945
Document number: DS38267 Rev. 1 - 2
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December 2015
© Diodes Incorporated
PAM8945
IMPORTANT NOTICE
NEW PRODUCT
DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
(AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes
without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the
application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or
trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall assume
all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diodes Incorporated
website, harmless against all damages.
Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel.
Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and
hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees arising out of, directly or
indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings
noted herein may also be covered by one or more United States, international or foreign trademarks.
This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the
final and determinative format released by Diodes Incorporated.
LIFE SUPPORT
Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express
written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the
labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the
failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any
use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related
information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its
representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems.
Copyright © 2015, Diodes Incorporated
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PAM8945
Document number: DS38267 Rev. 1 - 2
9 of 9
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December 2015
© Diodes Incorporated