LM4731TA/NOPB National Semiconductor, LM4731TA/NOPB Datasheet - Page 6

• Manufacturer Part Number: LM4731TA/NOPB
• Description: IC AMP AUDIO PWR 25W AB TO220-15
• Manufacturer: National Semiconductor
• Type: Class ABr

Specifications of LM4731TA/NOPB

• Output Type: 2-Channel (Stereo)
• Max Output Power X Channels @ Load: 25W x 2 @ 8 Ohm
• Voltage - Supply: 20 V ~ 56 V, ±10V ~ 28 V
• Features: Depop, Mute, Short-Circuit and Thermal Protection
• Mounting Type: Through Hole
• Package / Case: TO-220-15 (Bent and Staggered Leads)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *LM4731TA; *LM4731TA/NOPB; LM4731TA

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External Components Description
( See Figures 1 - 4 )
1
2
3
4
5
6
7
8
9
Note 13: Optional components dependent upon specific design requirements.
Components
R
R
R
C
(Note 13)
C
R
(Note 13)
R
(Note 13)
C
(Note 13)
R
(Note 13)
C
(Note 13)
L (Note 13)
R (Note 13)
R
C
R
(Note 13)
R
R
B
i
f
i
S
V
IN
IN
SN
SN
A
A
INP
BI
E
Prevents currents from entering the amplifier’s non-inverting input which may be passed through to the load
upon power down of the system due to the low input impedance of the circuitry when the undervoltage
circuitry is off. This phenomenon occurs when the supply voltages are below 1.5V.
Inverting input resistance to provide AC gain in conjunction with R
Feedback resistance to provide AC gain in conjunction with R
Feedback capacitor which ensures unity gain at DC. Also creates a highpass filter with R
Provides power supply filtering and bypassing. Refer to the Supply Bypassing application section for proper
placement and selection of bypass capacitors.
Acts as a volume control by setting the input voltage level.
Sets the amplifier’s input terminals DC bias point when C
create a highpass filter at f
Input capacitor which blocks the input signal’s DC offsets from being passed onto the amplifier’s inputs.
Works with C
Works with R
pole is set at f
Provides high impedance at high frequencies so that R may decouple a highly capacitive load and reduce
the Q of the series resonant circuit. Also provides a low impedance at low frequencies to short out R and
pass audio signals to the load. Refer to Figure 4.
Provides DC voltage biasing for the transistor Q1 in single supply operation.
Provides bias filtering for single supply operation.
Limits the voltage difference between the amplifier’s inputs for single supply operation. Refer to the Clicks
and Pops application section for a more detailed explanation of the function of R
Provides input bias current for single supply operation. Refer to the Clicks and Pops application section for
a more detailed explanation of the function of R
Establishes a fixed DC current for the transistor Q1 in single supply operation. This resistor stabilizes the
half-supply point along with C
SN
SN
C
= 1/(2πR
to stabilize the output stage by creating a pole that reduces high frequency instabilities.
to stabilize the output stage by creating a pole that reduces high frequency instabilities. The
SN
C
C
= 1/(2πR
SN
A
.
). Refer to Figure 4.
IN
C
IN
Functional Description
6
). Refer to Figure 4.
BI
.
IN
is present in the circuit. Also works with C
i
.
f
.
INP
.
i
at f
C
= 1/(2πR
IN
to
i
C
i
).