Datasheet

LM1876
www.ti.com SNAS097C –MAY 1999–REVISED APRIL 2013
(excluding active protection circuitry)
External Components Description
Components Functional Description
1 R
B
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.
2 R
i
Inverting input resistance to provide AC gain in conjunction with R
f
.
3 R
f
Feedback resistance to provide AC gain in conjunction with R
i
.
4 C
i
(1)
Feedback capacitor which ensures unity gain at DC. Also creates a highpass filter with R
i
at f
C
= 1/(2πR
i
C
i
).
5 C
S
Provides power supply filtering and bypassing. Refer to SUPPLY BYPASSING for proper placement and selection
of bypass capacitors.
6 R
V
(1)
Acts as a volume control by setting the input voltage level.
7 R
IN
(1)
Sets the amplifier's input terminals DC bias point when C
IN
is present in the circuit. Also works with C
IN
to create a
highpass filter at f
C
= 1/(2πR
IN
C
IN
). Refer to Figure 5.
8 C
IN
(1)
Input capacitor which blocks the input signal's DC offsets from being passed onto the amplifier's inputs.
9 R
SN
(1)
Works with C
SN
to stabilize the output stage by creating a pole that reduces high frequency instabilities.
10 C
SN
(1)
Works with R
SN
to stabilize the output stage by creating a pole that reduces high frequency instabilities. The pole is
set at f
C
= 1/(2πR
SN
C
SN
). Refer to Figure 5.
11 L
(1)
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
12 R
(1)
to the load. Refer to Figure 5.
13 R
A
Provides DC voltage biasing for the transistor Q1 in single supply operation.
14 C
A
Provides bias filtering for single supply operation.
15 R
INP
(1)
Limits the voltage difference between the amplifier's inputs for single supply operation. Refer to CLICKS AND
POPS for a more detailed explanation of the function of R
INP
.
16 R
BI
Provides input bias current for single supply operation. Refer to CLICKS AND POPS for a more detailed
explanation of the function of R
BI
.
17 R
E
Establishes a fixed DC current for the transistor Q1 in single supply operation. This resistor stabilizes the half-
supply point along with C
A
.
(1) Optional components dependent upon specific design requirements.
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