Datasheet

UNISONIC TECHNOLOGIES CO., LTD
PA3332
Preliminary
CMOS IC
2.6W STEREO AUDIO
AMPLIFIER

DESCRIPTION
The UTC PA3332 is a stereo audio power amplifier.
When the device is idle, it enters SHDN mode for some low
current consumption applications. The current dissipation is thus
reduced below 5μA. Mute function is included to mute the output.
Operating on a 5V power supply, the UTC PA3332 is capable of
driving a 4.0 Ω BTL load at a continuous average RMS output of
2.0W per channel with a less than 1% THD.%
There are two input paths, therefore, two different gain loops can
be set in the same PCB. We could choose one of the two gain paths
through the logic level of IN/IN pin. This increases the flexibility of
the hardware design. In order to prevent the speakers from
burned-out, the UTC PA3332 also has a function of maximum output
power clamping is designed.

FEATURES
* Including de-pop circuit
* Output power at 1% THD+N, VDD=5V
2.0W/CH (TYP.) into a 4Ω Load
1.3W/CH (TYP.) into a 8Ω Load
* Output power at 10% THD+N, VDD=5V
2.6W/CH (typical) into a 4Ω Load
1.6W/CH (typical) into a 8Ω Load
* BTL mode (Bridge-Tied Load)
* Maximum output power clamping circuitry contained
* Mute and shutdown control available
* Stereo input MUX

ORDERING INFORMATION
Ordering Number
PA3332G-N24-R

Package
HTSSOP-24
Packing
Tape Reel
MARKING
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PA3332
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Preliminary
CMOS IC
PIN CONFIGURATION
Note: Recommend connecting the Thermal Pad to the GND for excellent power dissipation.

PIN DESCRIPTION
PIN NO.
1, 12,
13, 24
2, 9, 11
3
4
5
6
7
PIN NAME
8
SHUTDOWN
10
14
15
LOUTMUTE
ROUTIN1/IN2
16
DESCRIPTION
GND/HS
Ground connection for circuitry, directly connected to thermal pad.
NC
LOUT+
LIN1
LIN2
LBPASS
LVDD
Embedded test mode pin, please keep it floating.
Left channel + output in BTL mode
Left channel IN1 input, selected when IN1 /IN2 pin is held low.
Left channel IN2 input, selected when IN1 /IN2 pin is held high.
Connect to voltage divider for left channel internal mid-supply bias.
Supply voltage input for left channel and for primary bias circuits.
Shutdown mode control signal input, places entire IC in shutdown mode when held
high, IDD< 5µA.
Left channel - output in BTL mode.
Mode control signal input, hold low for activation, hold high for mute.
Right channel - output in BTL mode
MUX control input, hold high to select in2 inputs (5,20), hold low to select in1 inputs
(4,21).
Ground connection for circuitry.
Supply voltage input for right channel.
Connect to voltage divider for right channel internal mid-supply bias.
Right channel in2 input, selected when IN1 /IN2 pin is held high.
Right channel in1 input, selected when IN1 /IN2 pin is held low.
Right channel + output in BTL mode
The output power can be clamped by setting a low bound voltage to this pin. The high
bound voltage will be generated internally. The output voltage will be clamped between
high/low bound voltages. Then the output power is lim-ited. It is weakly pull-low
internally, let this pin floating or tied to GND can deactivate this function.
Recommend connecting the Thermal Pad to the GND for excellent power dissipation.
17
18
19
20
21
22
GND
RVDD
RBYPASS
RIN2
RIN1
ROUT+
23
VOL
Thermal Pad
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
Preliminary
CMOS IC
BLOCK DIAGRAM
21
20
19
RIN1
RIN2
RIGHT
MUX
RBYPASS
-
ROUT+
+
ROUT- 15
RVDD
14
MUTE
Bias, Mute,
Shutdown,
and MUX Control
8 SHUTDOWN
23 VOL
22
18
IN1/IN2 16
LVDD
7
6 LBYPASS
+
5
4
LIN2
LIN1
LEFT
MUX
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-
LOUTLOUT+
10
3
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Preliminary
CMOS IC
ABSOLUTE MAXIMUM RATING
PARAMETER
SYMBOL
RATINGS
UNIT
Supply Voltage
VDD
6
V
Input Voltage
VIN
-0.3~VDD+0.3
V
Operating Ambient Temperature
TA
-40 ~ +85
°C
Junction Temperature
TJ
150
°C
Storage Temperature
TSTG
-65 ~ +150
°C
Reflow Temperature (soldering, 10sec)
260
°C
TA ≤ 25°C
2.7
Power Dissipation (Note 2)
TA ≤ 70°C
PD
1.7
W
TA ≤ 85°C
1.4
Electrostatic Discharge
VESD
-3000 ~ 3000 (Note 3)
V
Human Body Mode
Notes: 1. Absolute maximum ratings are those values beyond which the device could be permanently damaged.
Absolute maximum ratings are stress ratings only and functional device operation is not implied.
2. Recommended PCB Layout
3. Human body model : C = 100pF, R = 1500Ω, 3 positive pulses plus 3 negative pulses

ELECTRICAL CHARACTERISTICS
PARAMETER
SYMBOL
DC Electrical Characteristics (TA=+25°C)
TEST CONDITIONS
MIN
VDD =3.3V
Stereo BTL
VDD = 5V
Stereo BTL
DC Differential Output Voltage
VO(DIFF) VDD = 5V,Gain = 2
IDD in Shutdown
ISD
VDD = 5V
AC Operation Characteristics (VDD = 5.0V, TA=+25°C, RL = 4Ω, unless otherwise noted)
THD = 1%, BTL, RL = 4Ω
THD = 1%, BTL, RL = 8Ω
Output Power (Note)
POUT
THD = 10%, BTL, RL = 4Ω
THD = 10%, BTL, RL = 8Ω
PO = 1.6W, BTL, RL = 4Ω
Total Harmonic Distortion Plus Noise THD+N PO = 1W, BTL, RL = 8Ω
VI = 1V, RL = 10KΩ, G = 1
Max Output Power Bandwidth
BOM
G = 1, THD = 1%
Phase Margin
RL = 4Ω, Open Load
Power Supply Ripple Rejection
PSRR f = 120Hz
Mute Attenuation
Channel-To-Channel Output
f = 1kHz
Separation
IN1/IN2 Input Separation
Input Impedance
ZI
Signal-To-Noise Ratio
PO = 500mW, BTL
Output Noise Voltage
Vn
Output noise voltage
Note: Output power is measured at the output terminals of the IC at 1kHz.
Supply Current in Mute Mode
IDD(MTE)
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TYP MAX
7
8
5
2
13
16
50
5
UNIT
mA
mV
μA
2.0
1.3
2.6
1.6
100
60
10
20
60
65
90
m%
80
dB
80
2
90
55
dB
MΩ
dB
μV(rms)
W
kHz
°
dB
dB
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CMOS IC
ELECTRICAL CHARACTERISTICS (Cont.)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
AC Operation Characteristics (VDD =3.3V, TA=+25°C, RL = 4Ω, unless otherwise noted)
THD = 1%, BTL, RL = 4Ω
THD = 1%, BTL, RL = 8Ω
Output Power (Note)
POUT
THD = 10%, BTL, RL = 4Ω
THD = 10%, BTL, RL = 8Ω
PO = 0.7W, BTL, RL = 4Ω
Total Harmonic Distortion Plus Noise THD+N PO = 0.45W, BTL, RL = 8Ω
VI = 1V, RL = 10KΩ, G = 1
Max Output Power Bandwidth
BOM
G = 1, THD = 1%
Phase Margin
RL = 4Ω, Open Load
Power Supply Ripple Rejection
PSRR f = 120Hz
Mute Attenuation
Channel-To-Channel Output
f = 1kHz
Separation
IN1/IN2 Input Separation
Input Impedance
ZI
Signal-To-Noise Ratio
PO = 500mW, BTL
Output Noise Voltage
Vn
Output noise voltage
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TYP MAX
UNIT
0.85
0.55
1.1
0.7
270
100
10
20
60
65
90
m%
80
dB
80
2
90
55
dB
MΩ
dB
μV(rms)
W
kHz
°
dB
dB
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Preliminary
CMOS IC
APPLICATION INFORMATION
Input MUX Operation
For the UTC PA3332, there exist two input signal paths (IN1 and IN2). Thus, for different input sources, the UTC
PA3332 has different gains with this prompt setting. When the IN1 / IN2 pin is in active high, this device operates in
IN2 input source; when it is in active low, this device operates in IN1 input source.
Bridged-Tied Load Mode Operation
The following figure A shows the BTL (Bridged-Tied Load) mode operation. The two linear amplifiers drive both
ends of the speaker load.
There are several advantages for using the BTL mode: first of all, the differential driving to the speaker load
means that when one side is slewing up, the other side is slewing down, and vice versa. The voltage swing on the
load is two times that on a ground reference load. In this mode, the peak-to-peak voltage VO(PP) on the load will be
double a ground reference configuration. 4 times output power on the load will be generated at the same power
supply rail and loading due to the voltage on the load is doubled. Further more, this BTL operation can cancel the dc
offsets which save the using of dc coupling capacitor that is needed to cancel dc offsets in the ground reference
configuration. Then the input network and speaker responses can only limit the low-frequency performance.
Moreover, the saving of dc coupling capacitors can minimize PCB space and the cost.
MUTE and SHUTDOWN Mode Operations
Circuits with mute and shutdown functions are contained in the UTC PA3332, which is designed to reduce IDD
(supply current) to the absolute minimum level during nonuse periods for battery-power conservation.
When pulling the shutdown pin (pin 8) high, all linear amplifiers will be deactivated to mute the amplifier outputs.
Then the device enters an extremely low current consumption condition, the supply current is less than 5µA. When
the mute pin (pin 14) is pulled high, it will force the activated linear amplifier to supply the VDD/2 dc voltage on the
output & shutdown the second linear amplifiers to mute the AC performance. The current dissipation will be smaller
in the mute mode operation than that in the BTL mode.
It is not allowed to leave the shutdown and mute pins floating, or unexpected conditions would occur for the
amplifier operations.
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Preliminary
CMOS IC
APPLICATION INFORMATION (Cont.)
Maximum Power Clampping Function
The UTC PA3332 incorporated the maximum power clamping function that effectively reduces damage the
speaker due to the larger power through the speaker. The Vol pin (pin 23) is weakly pull-low internally. If a non-zero
voltage applies in the Vol pin, the UTC PA3332 will generate a high boundary voltage which the difference between
the VDD/2 and the high boundary voltage is the same as the difference between the VDD/2 and the low boundary
voltage. (i.e. VOH – VDD/2 = VDD/2 – VOL). Then the outputs of linear amplifiers will be effectively limited between the
high/low boundary voltage, the maximum output power is clamped. Thus, the maximum power is controlled
perfectively by means of setting the value of Vol,
Note that if this function is not used, the Vol pin should be connected to the GND or be floated.
Optimizing DEPOP Operation
The UTC PA3332 contains a circuit that can reduce poping to minimum during the power-up or shutdown mode.
The poping can be generated as long as a voltage step is applied to the speaker and the differential voltage
generated at the two ends of the speaker.
To get a minimum poping, the bypass capacitor is critical, 1/(CBx100kΩ) ≦ 1/(CI*(RI+RF)). (Where CB is the
mid-rail bypass capacitor, 100kΩ is the output impedance of the mid-rail generator, RI is the input impedance, CI is
the input coupling capacitor, RF is the gain setting impedance which is on the feedback path. CB is the most
important capacitor. It can be applied in reducing the poping together with determining the rate at which the amplifier
starts up during startup or recovery from shutdown mode.)
The Figure B shows the de-poping circuit for the UTC PA3332. The PNP transistor effectively controls the
voltage drop across the 50kΩ by slewing the internal node slowly when power is applied.
At start-up, the voltage at BYPASS capacitor is zero. The PNP is ON to pull the mid-point of the bias circuit
down. So the capacitor sees a lower effective voltage, and thus the charging is slower. This appears as a linear
ramp (while the PNP transistor is conducting), followed by the expected exponential ramp of an RC circuit.
VDD
100kΩ
Bypass
50kΩ
100kΩ
Figure B.
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
Preliminary
CMOS IC
TEST CIRCUIT
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
Preliminary
CMOS IC
TYPICAL APPLICATION CIRCUIT
Table 1. Logical Truth Table
Mute
X
Low
Low
High
High
1IN /IN2
X
Low
High
Low
High
Shutdown
High
Low
Low
Low
Low
Input
X
L/R IN1
L/R IN2
L/R IN1
L/R IN2
OUTPUT
L/R Out+
L/R OutOutput
Output
Output
Output
Output
Output
-
Mode
Shutdown (Mute)
BTL
BTL
Mute
Mute
UTC assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or
other parameters) listed in products specifications of any and all UTC products described or contained
herein. UTC products are not designed for use in life support appliances, devices or systems where
malfunction of these products can be reasonably expected to result in personal injury. Reproduction in
whole or in part is prohibited without the prior written consent of the copyright owner. The information
presented in this document does not form part of any quotation or contract, is believed to be accurate
and reliable and may be changed without notice.
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