PAM PAM8902

PAM8902
30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers
Key Features
General Description
n Supply Voltage Range From 2.5 V to 5.5 V
n 30 Vpp Output Load Voltage From a 2.5 V
Supply
n Integrated Boost Converter Generates 17.5V
Supply
n Programmable softstart
n Small Boost Converter Inductor
n Selectable Gain of 18 dB, 22 dB, and 26 dB
n Selectable Boost output voltage of 8V, 12V,
and 17.5V
n Low Shutdown Current: <1uA
n Build in Thermal , OCP ,OVP,Short protection
n Available in Space Saving Packages:
16-ball 1.95mmx1.95mm CSP package
16-pin QFN4x4 package
The PAM8902 is a mono, Class-D audio amplifier
with integrated boost convertor 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 easy for using.PAM8902 also
provides thermal ,short, under and over voltage
protection.
T h e PA M 8 9 0 2 i s a v a i l a b l e i n a 1 6 - b a l l
1.95mmx1.95mm CSP package and 16-pin QFN4x4
package.
Applications
n
n
n
n
n
Wireless or Cellular Handsets
Por t able DVD Player
Personal Digital Assistants (PDAs )
Electronic Dictionaries
Digital Still Cameras
Typical Application Circuit
*Option(Refer to Application Information)
L1
Battery
4.7μH
C1
10 μF
SW
AVDD
VOUT
ENA
C2
GSET
10 μF
PGND1
VSET
PVCC
22nF 56k
COMP
PAM8902
1 μF
VCM
22uH
OUT+
0.1μF
VIN
INP
0.1 μF
INN
10Ω
OUTPGND2
GND
Power Analog Microelectronics, Inc
www.poweranalog.com
01/2012 Rev1.4
1
PAM8902
30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers
Block Diagram
Comp
PVCC
Vref
Resistor
Divider
feedback
SW
VOUT
+
GM
-
PWM
+
PWM Logic
And Driver
+
Σ
ENA
CS
-
Enable
Ramp
Generator
PGND1
GSET
Gain
Vout
Setting
1.5MHz
Oscillator
VSET
AVDD
Bias and
Vref
VCM/SS
PLL
375KHz
Protection Function
VCM
PVCC
OUT+
INN
Gain
Adjust
INP
-
PWM
Modulator
+
Level
Shift
and
H-Bridge
OUT-
PGND2
AGND
Power Analog Microelectronics, Inc
www.poweranalog.com
01/2012 Rev1.4
2
PAM8902
30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers
Pin Configuration & Marking Information
16 Ball CSP
Top View
PVCC
VOUT
SW
PGND1
A1
A2
A3
A4
OUT+
VSET
COMP
B1
B2
B3
OUT-
GSET
VCM
C1
C2
C3
C4
PGND2
ENA
INN
INP
D1
D2
D3
D4
Marking
BG
YW
AVDD
B4
AGND
BG: Product Code of PAM8902
Y: Year
W: Week
Top View
QFN 4X4 16L
16
15
14
13
VOUT 1
SW
2
VSET
3
PGND1
4
P8902
XXXYW
5
6
7
12
ENA
11
GSET
10
INN
9
INP
Y: Year
W: Week
X: Internal Code
8
: Pin 1 Indicator
Power Analog Microelectronics, Inc
www.poweranalog.com
01/2012 Rev1.4
3
PAM8902
30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers
Pin Configuration
Bump(CSP) Pin NO.(QFN)
A1
16
A2
1
A3
2
A4
4
B1
15
B2
3
B3
5
B4
6
C1
14
C2
11
C3
7
C4
8
D1
13
D2
12
D3
10
D4
9
Name
PVCC
VOUT
SW
PGND1
OUT+
VSET
COMP
AVDD
OUTGSET
VCM
AGND
PGND2
ENA
INN
INP
Description
Audio Amplifier Power Supply
Boost Convertor Output
Boost Convertor Switching Node
Boost Convertor Power Ground
Positive Differential Audio Output
Boost Convertor Output Voltage Setting(8V,12V,17.5V)
Boost Convertor compensation
Power Supply
Negative Differential Audio Output
Amplifier Gain setting ( 18dB , 22dB , 26dB)
Common Mode bypass Cap
Analog Ground
Class D Power Ground
Whole chip Enable
Negative Differential Audio Input
Positive Differential Audio Input
Absolute Maximum Ratings
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.
Supply Voltage . ...........................................6.0V
Input Voltage.............................-0.3V to V DD+0.3V
Storage Temperature.....................-65°C to 150 °C
Maximum Junction Temperature..................150°C
Soldering Temperature....................250°C,10 sec
Recommended Operating Conditions
Supply voltage Range........................ 2.5V to 5.5V
Ambient Temperature Range............-40 °C to 85 °C
Junction Temperature Range......... -40°C to 125°C
Thermal Information
Parameter
Symbol
Thermal Res istance (Junc tion to ambient)
θJA
Thermal Resistance (Junction to case)
θJC
Package
Max imum
CSP
90
QFN4X4-16
52
CSP
75
QFN4X4-16
30
Unit
°C/W
°C/W
Power Analog Microelectronics, Inc
www.poweranalog.com
01/2012 Rev1.4
4
PAM8902
30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers
Electrical Characteristic
T A=25 °C, V DD =3.6V,CL =1uF,Vset float, unless otherwise noted .
Parameter
Input voltage
Quiescent Current
Shutdown Current
Wake-Up tim e
Chip Enable
Chip Disable
GSET/VSET High
GSET/VSET Floating
GSET/VSET Low
Under Voltage lockout thres hold
Under Voltage lockout Hysteres is
Therm al s hutdown threshold
Therm al s hutdown lockout Hysteresis
Symbol T est Condition
Vdd
EN>1.2V, VSET = High
IQ
EN>1.2V, VSET = Floating
EN>1.2V, VSET = GND
ISD
EN=0V
Twu
EN from low to high
Veh
Vel
Vh
Vf
Vl
UVLO Vdd from high to low
UVLOh Vdd from low to high
OTP
OTPh
M in
2.5
Typ
30
10
5
0.1
40
M ax
5.5
48
18
12
1
1.2
0.4
Vdd
Vdd-1
0.5
Vdd-0.5
1
0
2.2
0.2
150
30
Unit
V
mA
uA
mS
V
V
V
℃
℃
Boost Convertor
Current Lim it
Low Side Mosfet Rdson
Boost switching frequenc y
Vo1
Vo2
Vo3
Cl
Rls
Foscb
Class D
Class D Amplifier Switching Frequency
Com mon mode reject ratio
Ouput offset voltage
Foscd
CMRR
Vos
Output Voltage
Rds on
Closed-loop voltage gain
Power supply reject ratio
Total harmonic distortion plus noise
Signal to noise ratio
VSET=GND , No load
VSET=NC , No load
VSET=AVDD , No load
Average input current
Io=50m A
7.2
10.8
16
1.1
Input AC-GND
Vin=+-100mV, Vdd=3.6V
output offset voltage
High side
Rp
Low side
Av1
Gset=AVDD,Vo=1Vrms
Av2
Gset=NC,Vo=1Vrms
Av3
Gset=GND,Vo=1Vrms
PSR R 200m Vpp s upply ripple at 217Hz
THD+N Vo=5Vrms
SNR
Input AC Ground,A-weighting
225
25
21
17
8
12
17.5
0.8
0.5
1.5
8.8
13.2
19
375
60
5
1.5
0.6
26
22
18
70
0.3
90
475
1.9
V
V
V
A
Ω
MHz
50
KHz
dB
mV
Ω
Ω
27
23
19
dB
dB
%
dB
Power Analog Microelectronics, Inc
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01/2012 Rev1.4
5
PAM8902
30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers
Typical Operating Characteristics
T A=25 °C, V DD=4.2V,Gain=26dB,Cin=1uF,Cload=1uF, unless otherwise noted .
1. Total Supply Current VS Output Voltage
2. Total Input Power VS Output Voltage
0 .6
160
140
0 .5
120
0 .4
100
0 .3
80
60
0 .2
40
VDD=3.6V
VD D = 3.6 V
0 .1
VDD=4.2V
20
VD D = 4.2 V
VDD=5.5V
VD D = 5.5 V
0
0
0
2
4
6
8
10
12
0
2
4
Out put Voltage(V rms)
3. THD+N VS Frequency
8
10
12
4. THD+N VS Frequency
10
5
6
O u tp ut Vo lt ag e(V rm s)
10
VDD=3.6V
5
2
VDD=5.5V
2
Vo=2Vrms
1
Vo=2Vrms
1
Vo=4Vrms
0.5
0.5
Vo=4Vrms
0.2
0.2
0.1
0.1
0.05
0.03
20
0.05
Vo=6Vrms
50
100
200
500
1k
2k
5k
10k
Vo=6Vrms
0.03
20
20k
50
100
1k
2k
5k
10k
20k
Frequency(Hz)
Frequency(Hz)
5. Output Voltage RMS VS Frequency
6. Output Voltage RMS VS Frequency
18
18
ΤΗD=1%
Vset High
16
VDD=5.5V
14
ΤΗD=10%
Vset High
VDD=5.5V
14
12
12
10
10
8
8
6
VDD=4.2V
6
VDD=4.2V
4
4
VDD=3.6V
2
0
20
500
Hz
Hz
16
200
50
100
200
500
1k
2k
5k
10k
VDD=3.6V
2
0
20
20k
Hz
50
100
200
500
1k
2k
5k
10k
20k
Hz
Frequency(Hz)
Frequency(Hz)
Power Analog Microelectronics, Inc
www.poweranalog.com
01/2012 Rev1.4
6
PAM8902
30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers
Typical Operating Characteristics
T A=25 °C, V DD=5V,Gain=18dB, unless otherwise noted .
7. Output Voltage RMS VS Frequency
8. Output Voltage RMS VS Frequency
10
12
8
7
11
VDD=5.5V
9
ΤΗD=10%
Vset Floating
VDD=5.5V
10
ΤΗD=1%
Vset Floating
9
8
6
7
5
6
VDD=4.2V
4
5
VDD=4.2V
4
3
VDD=3.6V
2
3
VDD=3.6V
2
1
0
20
1
50
100
200
500
1k
2k
5k
10k
0
20
20k
50
100
200
500
Hz
Frequency(Hz)
5k
10k
20k
10. Output Voltage RMS VS Frequency
8
8
ΤΗD=1%
Vset Low
2k
Frequency(Hz)
9. Output Voltage RMS VS Frequency
7
1k
Hz
7
VDD=5.5V
6
6
5
5
4
ΤΗD=10%
Vset Low
VDD=5.5V
VDD=4.2V
4
VDD=4.2V
3
VDD=3.6V
3
VDD=3.6V
2
2
1
1
0
20
50
100
200
500
1k
2k
5k
10k
0
20
20k
50
100
Hz
Frequency(Hz)
500
Hz
1k
2k
5k
10k
20k
9
10
Frequency(Hz)
11. Output Voltage RMS VS THD+N
12. Output Voltage RMS VS THD+N
20
20
VDD=3.6V
Vset High
10
5
2
2
1
1
0.5
0.5
0.2
0.2
0
2
VDD=4.2V
Vset Floating
10
5
0.1
200
4
6
8
10
12
14
0.1
16
0
1
2
3
4
5
6
7
8
V
V
Output Voltage RMS
Output Voltage RMS
Power Analog Microelectronics, Inc
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01/2012 Rev1.4
7
PAM8902
30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers
Application Information
Select Boost Convertor 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
Connect to AVDD
Floating
Min
AVDD - 0.5V
1V
Max
AVDD
AVDD - 1V
PVCC Voltage
17.5V
12V
Audio amplifier maximum output voltage
11Vrms (Vpp=31.1V)
8Vrms(Vpp=22.6V)
Connect to GND
GND
0.5V
8V
5Vrms(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)
Gs et
Gs et=Vdd
Gset=Floating
Gset=GND
Rin
77.4kΩ
100kΩ
122.6kΩ
Rfb
122.6kΩ
100kΩ
77.4kΩ
Where Rin is a 77.4K Ω internal resistor, Rex is the external input resistor,Rf is a 122.6K Ω 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 ov erall
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
2pRiCi
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 Ω and the specification calls for a flat bass response are down to 150Hz.
Equation is reconfigured as followed:
1
Ci =
2p 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 tanta lum 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 V DD/2, which is likely higher
than the source DC level. Please note that it is important to confirm the capacitor polarity in the application.
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 differ ent types
of noise on the power supply leads. For higher frequency transients, spikes, or digital hash on the line, a
Power Analog Microelectronics, Inc
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01/2012 Rev1.4
8
PAM8902
30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers
Application Information
good low equivalent series-resistance (ESR) ceramic capacitor, typically 1 μF, 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 10 μF 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 ca n remove
the external schottky diode to reduce the cost.
1. Vset = GND or Floating and C L less than 1uF.
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 PAM89 02
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 dro ps 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-to-GND 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 tem perature
exceeds the set point, the device will enter the shutdown state and the outp uts are disabled,in this
condition both OUT+ and OUT- will become high impedance. This is not a latched fault. The thermal f ault 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 int eraction.
Power Analog Microelectronics, Inc
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01/2012 Rev1.4
9
PAM8902
30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers
Ordering Information
PAM8902 X X X - P
PAM Confidential
Number of pins
Package Type
Pin Configuration
Part Number
Marking
BG
PAM8902ZER-P
YW
P8902
PAM8902KER-P
X XXYW
Package Type
MOQ
CSP-16L
3,000 Units/ Tape & Reel
QFN4X4-16L
3,000 Units/ Tape & Reel
Marking Instruction
Y : Last Digital of Manufacturing Year
6: 2006
7: 2007
8: 2008
9: 2009
0: 2010
1: 2011
W : Week Code
1
2
3
4
Week
code
A
B
C
D
14
15
16
17
Week
code
N
O
P
Q
5
6
7
E
F
G
18
19
20
8
9
10
11
12
H
I
J
K
L
13
M
Item
27
28
29
30
Week
code
A
B
C
D
R
S
T
31
32
33
21
22
23
24
25
U
V
W
X
Y
26
Z
Item
40
41
42
43
Week
code
N
O
P
Q
E
F
G
44
45
46
R
S
T
34
35
36
37
38
H
I
J
K
L
47
48
49
50
51
U
V
W
X
Y
39
M
52
Z
Item
Item
Power Analog Microelectronics, Inc
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01/2012 Rev1.4
10
PAM8902
30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers
Outline Dimensions
CSP-16
1.00
1.95 ±0.02
0.50
4
1.93 ±0.02
D
Coplanarity(Flatness) Max 0.05
Units:Millimeter
0.235±0.02 (Stand off)
0.38 ±0.04
Power Analog Microelectronics, Inc
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01/2012 Rev1.4
11
PAM8902
30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers
Outline Dimensions
QFN4X4-16
Power Analog Microelectronics, Inc
www.poweranalog.com
01/2012 Rev1.4
12
PAM8902
30-Vpp Mono Class-D Audio Amplifier for Piezo/Ceramic Speakers
Datasheet Revision History
Date
Revision
Description
Comment
03/03/2011
Advanced
04/07/2011
Preliminary
05/25/2011
Rev1.0
Initially releas ed
11/22/2011
Rev1.1
Add "Application Information"
12/15/2011
Rev1.2
Add "-P" to the part number in "Ordering Information"
12/22/2011
Rev1.3
Add "Pin1 Indicator" on page3 and add "Mark ing Instruction" on page10
Update "Thermal Information" and"Electrical Charateris tic"
12/28/2011
Rev1.3
Add "Coplanarity(Flatness)" value in the outline dim ension
01/05/2012
Rev1.4
Add "PSRR, THD+N, SNR" parameters to s pec
Change produc t c ode from "BH" to "BG"
Update "Block Diagram"
Power Analog Microelectronics, Inc
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01/2012 Rev1.4
13