Tel: 886-2-66296288
Fax: 886-2-29174598
URL: http://www.princeton.com.tw
2-Channel 300mW Class AB Power Amplifier
PT2308P
DESCRIPTION
PT2308P is a 2 channel Class AB stereo speaker driver utilizing CMOS technology designed by AB
push-pull, the original sound will be low distortion amplify and low consumption. The power of PT2308P
will be reach 300mW on THD=10% and deliver 8Ω load.
FEATURES
Wild operating temperature large
Excellent Power Signal-to-Noise Repel Rate (PSRR)
Low static state current consumption
Output power (THD=10％)
- Load is 16Ω/190mW
- Load is 8Ω/300mW
•
Low harmonics distortion (THD=0.03%)
•
Large output amplitude
•
•
•
•
APPLICATIONS
•
•
•
•
Walkman
Portable audio
HI-FI audio system
CD-ROM
PT2308P V1.0
-1-
November, 2005
Tel: 886-2-66296288
Fax: 886-2-29174598
URL: http://www.princeton.com.tw
2-Channel 300mW Class AB Power Amplifier
PT2308P
BLOCK DIAGRAM
OUT 1
1
IN1-
2
IN1+
3
VS S
4
-
OP1
+
8
VDD
7
OUT 2
-
OP2
+
6
IN2-
5
IN2+
PT2308P V1.0
-2-
November, 2005
Tel: 886-2-66296288
Fax: 886-2-29174598
URL: http://www.princeton.com.tw
2-Channel 300mW Class AB Power Amplifier
PT2308P
PIN CONFIGURATION
OUT 1
IN1-
IN1+
VS S
1
2
3
4
PT 2308P
8
7
6
5
VD D
OUT 2
IN2-
IN2+
PIN DESCRIPTION
Pin Name
OUT1
IN1-
IN1+
VSS
IN2+
IN2-
OUT2
VDD
I/O
O
I
I
-
I
I
O
-
Description
Output pin 1
Inverting input pin 1
Non-inverting input pin 1
Negative power supply
Non-inverting input pin 2
Inverting input pin 2
Output pin 2
Positive power supply
Pin No.
1
2
3
4
5
6
7
8
PT2308P V1.0
-3-
November, 2005
Tel: 886-2-66296288
Fax: 886-2-29174598
URL: http://www.princeton.com.tw
2-Channel 300mW Class AB Power Amplifier
PT2308P
BASIC APPLICATION DESCRIPTION
PT2308P is a low power amplifier which operates with a 5V input voltage, it can be used to drive
regular earphones or low power speakers with a load resistance of 8ohm or higher. The operation
mechanics is much like the typical OPAMP. (The picture below shows the basic application circuit of
PT2308P as an inverted amplifier).
R2
Vin
Ci
R1
Co
Vout
VREF
Show in one side
R3
RL
PT2308P Typical Application Circuit
1. Gain Settings
The inverted amplifier’s amplification is equal to the ratio between R2 and R1 (Av= -(R2÷R1)).
Please take note that the maximum supply voltage for the PT2308P is 5V, voltage gain setting
should depend on the input level amplitude; too much voltage gain may increase the chance of
causing clipping at the output.
2. VREF
Because the PT2308P operates with a single power source, to ensure the best output performance,
the suggested value for VREF is 1/2 VDD.
PT2308P V1.0
-4-
November, 2005
Tel: 886-2-66296288
Fax: 886-2-29174598
URL: http://www.princeton.com.tw
2-Channel 300mW Class AB Power Amplifier
PT2308P
3. Input Coupling Capacitor Ci
In typical applications, this input coupling capacitor transfers signals between the input and
PT2308P, it allows block DC bias of the PT2308P flowing into input signal, and thus the user must
be aware of the voltage tolerance and the polarity of this Cap.
Referring to the diagram above, Ci and R1 forms a 1
st
order high-pass filter; the lower-cutoff
frequency is determined by the equation:
f
c(highpass)
=1/2πR1Ci
The diagram below shows the frequency response when: Ci=10µF/1µF/0.47µF/0.22µF/0.1µF
PT2308P V1.0
-5-
November, 2005
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