A Product Line of
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NOT RECOMMENDED FOR NEW DESIGN
USE PAM8902H
PAM8902
30-VPP MONO CLASS-D AUDIO AMPLIFIER FOR PIEZO/CERAMIC SPEAKERS
Description
Pin Assignments
The PAM8902 is a mono, Class-D audio amplifier with integrated
boost converter designed for piezo and ceramic speakers.The
PAM8902 is capable of driving a ceramic/piezo speaker with
30VPP(10.6Vrms) from a 3.6V power supply.The PAM8902's Boost
converter operates at a fixed frequency of 1.5MHz, and provides a
17.5V supply with a minimum number of external components.
PAM8902 features an integrated audio low pass filter that rejects high
frequency noise thus improving audio fidelity. And three gain modes
of 18dB, 22dB and 26dB for ease of use. PAM8902 also provides
thermal, short, under- and over-voltage protection.
The PAM8902 is available in a 16-ball 1.95mm x 1.95mm CSP
package and 16-pin QFN4x4 package.
Features
Supply Voltage Range From 2.5V to 5.5V
30 VPP Output Load Voltage From a 2.5V Supply
Integrated Boost Converter Generates 17.5V Supply
Programmable Soft-Start
Small Boost Converter Inductor
Selectable Gain of 18dB, 22dB, and 26dB
Selectable Boost Output Voltage of 8V, 12V and 17.5V
Low Shutdown Current: < 1µA
Built-in Thermal, OCP, OVP, Short Protection
Available in Space Saving Packages:
16-ball 1.95mmx1.95mm CSP Package
16-pin QFN4x4 Package
Applications
Wireless or Cellular Handsets
Portable DVD Player
Personal Digital Assistants (PDAs )
Electronic Dictionaries
Digital Still Cameras
PAM8902
Document number: DS36454 Rev. 2 - 3
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PAM8902
Typical Applications Circuit
Pin Descriptions
Pin
Name
PVCC
VOUT
SW
PGND1
OUT+
VSET
COMP
AVDD
OUTGSET
VCM
AGND
PGND2
ENA
INN
INP
Bump
(CSP)
A1
A2
A3
A4
B1
B2
B3
B4
C1
C2
C3
C4
D1
D2
D3
D4
Pin Number
QFN4x4
16
1
2
4
15
3
5
6
14
11
7
8
13
12
10
9
PAM8902
Document number: DS36454 Rev. 2 - 3
Function
Audio Amplifier Power Supply
Boost Converter Output
Boost Converter Switching Node
Boost Converter Power Ground
Positive Differential Audio Output
Boost Converter Output Voltage Setting(8V,12V,17.5V)
Boost Converter Compensation
Power Supply
Negative Differential Audio Output
Amplifier Gain Setting ( 18dB , 22dB , 26dB)
Common Mode Bypass Cap
Analog Ground
ClassD Power Ground
Whole Chip Enable
Negative Differential Audio Input
Positive Differential Audio Input
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PAM8902
Functional Block Diagram
Absolute Maximum Ratings (@TA = +25°C, unless otherwise specified.)
These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may
affect device reliability. All voltages are with respect to ground.
Parameter
Supply Voltage
Input Voltage
Maximum Junction Temperature
Storage Temperature
Soldering Temperature
Rating
6.0
-0.3 to VDD +0.3
+150
-65 to +150
350, 10sec
Unit
V
°C
Recommended Operating Conditions (@TA = +25°C, unless otherwise specified.)
Parameter
Supply Voltage Range
Ambient Temperature Range
Junction Temperature Range
PAM8902
Document number: DS36454 Rev. 2 - 3
Rating
2.5 to 5.5
-40 to +85
-40 to +125
Unit
V
°C
°C
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PAM8902
Thermal Information
Parameter
Thermal Resistance (Junction to Ambient)
Thermal Resistance (Junction to Case)
Electrical Characteristics
Parameter
Input Voltage
Quiescent Current
Package
CSP
QFN4x4-16
CSP
QFN4x4-16
Symbol
θJA
θJC
Max
90
52
75
30
Unit
°C/W
(@TA = +25°C, VDD = 3.6V, CL = 1µF, VSET Float, unless otherwise specified.)
Symbol
Test Conditions
IQ
Min
Typ
2.5
VDD
Max
Units
5.5
V
EN > 1.2V, VSET = High
30
48
EN > 1.2V, VSET = Floating
10
18
EN > 1.2V, VSET = GND
5
12
1
Shutdown Current
ISD
EN = 0V
0.1
Wake-Up Time
TWU
EN from Low to High
40
Chip Enable
VEH
Chip Disable
VEL
GSET/ VSET High
VH
VDD -0.5
VDD
GSET/ VSET Floating
VF
1
VDD -1
VL
UVLO
UVLO(H)
OTP
OTP(H)
0
0.5
GSET/ VSET Low
Under Voltage Lockout Threshold
Under Voltage Lockout Hysteresis
Thermal Shutdown Threshold
Thermal Shutdown Lockout Hysyeresis
µA
mS
1.2
0.4
VDD from High to Low
VDD from Low to High
mA
2.2
0.2
150
30
V
V
V
°C
°C
Boost Converter
Output Voltage
V O1
VSET = GND, No Load
7.2
8
8.8
V
V O2
VSET = NC, No Load
10.8
12
13.2
V
16
17.5
19
V
V O3
VSET = AVDD, No Load
Current Limit
CL
Average Input Current
0.8
A
Lowside MOSFET RDS(ON)
RLS
IO = 50mA
0.5
Ω
Boost Switching Frequency
fOSCB
1.1
1.5
1.9
MHz
225
375
475
KHz
Class D
Class D Amplifier Switching Frequency
fOSCD
Common Mode Reject Ratio
CMRR
Output Offset Voltage
RDS(ON)
Closed-Loop Voltage Gain
Input AC-GND
60
VIN = + -100mV, VDD = 3.6V
5
dB
VOS
Output Offset Voltage
RP
High Side
Low Side
50
AV1
GSET = AVDD, VO = 1VRMS
25
26
27
AV2
GSET = NC, VO = 1VRMS
21
22
23
AV3
GSET = GND, VO = 1VRMS
17
18
19
mV
Ω
Ω
1.5
0.6
dB
Power Supply Reject Ratio
PSRR
200m VPP Supply Ripple @ 217Hz
70
Total Harmonic Distortion Plus Noise
THD+N
VO = 5VRMS
Input AC Ground, A–Weighting
0.3
%
90
dB
Signal to Noise Ratio
PAM8902
Document number: DS36454 Rev. 2 - 3
SNR
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dB
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PAM8902
Typical Performance Characteristics
(@TA = +25°C, VDD = 4.2V, Gain = 26dB, CIN = 1µF, CLOAD = 1µF, unless otherwise specified.)
PAM8902
Document number: DS36454 Rev. 2 - 3
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PAM8902
Typical Performance Characteristics (cont.) (@TA = +25°C, VDD = 5V, Gain = 18dB, unless otherwise specified.)
PAM8902
Document number: DS36454 Rev. 2 - 3
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PAM8902
Application Information
Select Boost Converter Output Voltage
Customer can use VSET pin to set boost converor output voltage between 8V, 12V and 17.5V. VSET pin configuration table as below:
VSET Pin Configuration
Min
Max
PVCC Voltage
Audio Amplifier
Maximum Output Voltage
Connect to AVDD
AVDD – 0.5
AVDD
17.5V
11 VRMS (VPP = 31.1V)
Floating
1V
AVDD – 1V
12V
8 VRMS (VPP = 22.6V)
Connect to GND
GND
0.5V
8V
5 VRMS (VPP = 14.1V)
Input Resistance (RI)
The input resistors (RI = RIN + REX) set the gain of the amplifier according to Equation 1 when anti-saturation is inactive.
G = 20 Log [12.8*RF/ (RIN + REX)] (dB)
GSET
RIN
RFB
77.4kΩ
122.6kΩ
GSET = VDD
GSET = Floating
100kΩ
100kΩ
GSET = GND
122.6kΩ
77.4kΩ
Where RIN is a 77.4KΩ internal resistor, REX is the external input resistor, RF is a 122.6KΩ internal resistor. Resistor matching is very important
in fully differential amplifiers. The balance of the output on the reference voltage depends on matched ratios of the resistors. CMRR, PSRR, and
cancellation of the second harmonic distortion diminish if resistor mismatch occurs. Therefore, it is recommended to use 1% tolerance resistors
or better to keep the performance optimized. Matching is more important than overall tolerance. Resistor arrays with 1% matching can be used
with a tolerance greater than 1%. Place the input resistors very close to the PAM8902 to limit noise injection on the high-impedance nodes. For
optimal performance the gain should be set to lower. Lower gain allows the PAM8902 to operate at its best, and keeps a high voltage at the input
making the inputs less susceptible to noise. In addition to these features, higher value of RI minimizes pop noise.
Input Capacitors (CI)
In the typical application, an input capacitor, CI, is required to allow the amplifier to bias the input signal to the proper DC level for optimum
operation. In this case, Ci and the minimum input impedance RI form is a high-pass filter with the corner frequency determined in the follow
equation:
FC
1
2 RI CI
It is important to consider the value of CI as it directly affects the low frequency performance of the circuit.
For example, when RI is 150k and the specification calls for a flat bass response are down to 150Hz.
Equation is reconfigured as followed:
CI
1
2 RIFC
When input resistance variation is considered, the CI is 7nF, so one would likely choose a value of 10nF. A further consideration for this
capacitor is the leakage path from the input source through the input network (CI, RI + RF) to the load. This leakage current creates a DC offset
voltage at the input to the amplifier that reduces useful headroom, especially in high gain applications. For this reason, a low-leakage tantalum or
ceramic capacitor is the best choice. When polarized capacitors are used, the positive side of the capacitor should face the amplifier input in
most applications as the DC level is held at VDD /2, which is likely higher than the source DC level. Please note that it is important to confirm the
capacitor polarity in the application.
PAM8902
Document number: DS36454 Rev. 2 - 3
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PAM8902
Application Information
Decoupling Capacitor
The PAM8902 is a high-performance CMOS audio amplifier that requires adequate power supply decoupling to ensure the output total harmonic
distortion (THD) as low as possible. The optimum decoupling is achieved by using two different types of capacitors that target on different types
of noise on the power supply leads. For higher frequency transients, spikes, or digital hash on the line, a good low equivalent series-resistance
(ESR) ceramic capacitor, typically 1µF is placed as close as possible to the device AVDD pin for the best operation. For filtering lower frequency
noise signals, a large ceramic capacitor of 10µF or greater placed near the AVDD supply trace is recommended.
External Schottky Diode
Use external schottky diode can get the best driving capability and efficiency.
Since internal power diode has limited driving capability, only in following conditions customer can remove the external schottky diode to reduce
the cost.
1. VSET = GND or Floating and CL less than 1µF.
2. The signal frequency less than 4KHz.
3. Haptic application (50-500Hz)
Shutdown Operation
In order to reduce power consumption while not in use, the PAM8902 contains shutdown circuitry amplifier off when a logic low is placed on the
ENA pin. By switching the ENA pin connected to GND, the PAM8902 supply current draw will be minimized in idle mode.
Under-Voltage Lock-Out (UVLO)
The PAM8902 incorporates circuitry designed to detect supply voltage. When the supply voltage drops to 2.2V or below, the PAM8902 goes into
a state of shutdown, and the device comes out of its shutdown state and restore to normal function only when reset the power supply or ENA
pin.
Short-Circuit Protection (SCP)
The PAM8902 has short circuit protection circuitry on the outputs to prevent the device from damage when output-to-output shorted or output-toGND shorted occurs. When a short circuit occurs, the device goes into a latch state and must be reset by cycling the voltage on the ENA pin to a
logic low and then back to the logic high state for normal operation. This will clear the short-circuit flag and allow for normal operation if the short
was removed. If the short was not removed, the protection circuitry will again activate.
Over-Temperature Protection (OTP)
Thermal protection on the PAM8902 prevents the device from damage when the internal die temperature exceeds +150°C. There is a +15°C
tolerance on this trip point from device to device. Once the die temperature exceeds the set point, the device will enter the shutdown state and
the outputs are disabled in this condition both OUT+ and OUT- will become high impedance. This is not a latched fault. The thermal fault is
cleared once the temperature of the die decreased by +30°C. This large hysteresis will prevent motor boating sound well and the device begins
normal operation at this point with no external system interaction.
PAM8902
Document number: DS36454 Rev. 2 - 3
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PAM8902
Ordering Information
PAM8902 X X X - P
Pin Configuration
Package Type
Number of Pins
PAM Confidential
R: 16
Part Number
Part Marking
BG
YW
P8902
XXXYW
PAM8902ZER-P
PAM8902KER-P
Package Type
Standard Package
CSP-16L
3000Units/Tape&Reel
QFN4x4-16L
3000Units/Tape&Reel
Marking Information
Y: Last Digital of Manufacturing Year
6: 2006
7: 2007
8: 2008
9: 2009
0: 2010
1: 2011
W: Week Code
Item
1
2
3
4
5
6
7
8
9
10
11
12
13
Week Code
A
B
C
D
E
F
G
H
I
J
K
L
M
PAM8902
Document number: DS36454 Rev. 2 - 3
Item
14
15
16
17
18
19
20
21
22
23
24
25
26
Week Code
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Item
27
28
29
30
31
32
33
34
35
36
37
38
39
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Week Code
A
B
C
D
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F
G
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K
L
M
Item
40
41
42
43
44
45
46
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49
50
51
52
Week Code
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
September 2016
© Diodes Incorporated
A Product Line of
Diodes Incorporated
PAM8902
Marking Information (cont.)
PAM8902
Document number: DS36454 Rev. 2 - 3
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PAM8902
Package Outline Dimensions (All dimensions in mm.)
CSP-16
PAM8902
Document number: DS36454 Rev. 2 - 3
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PAM8902
Package Outline Dimensions (cont.) (All dimensions in mm.)
QFN4x4-16
PAM8902
Document number: DS36454 Rev. 2 - 3
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PAM8902
IMPORTANT NOTICE
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).
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Copyright © 2012, Diodes Incorporated
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PAM8902
Document number: DS36454 Rev. 2 - 3
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