AN12942B Datasheet, PDF (15/31 Pages) Panasonic Semiconductor – Audio signal processing IC for notebook PC

AN12942B
„ Technical Data (continued)
• Circuit diagrams of the input/output part and pin function descriptions (continued)
Note) The characteristics listed below are reference values based on the IC design and are not guaranteed.
Pin Waveform
No. _{and voltage}
Inner circuit
Impedance
Description
Beep entry
34
DC: 2.25 V
AC: 3.3 V_PP
180
34
6.75k
18k
V_REF (2.25 V)
The entry
impedance: About
180 kΩ
It is the entry pin to enter beep signal.
The same signal is entered both by
L-channel and R-channel with the audio
signal mix amplifier of the following
paragraph.
V_REF
18
DC: 2.25 V
V_CC (5 V)
440k
18
360k
The entry
impedance: About
200 kΩ
With the pin to fix the bias voltage (the
operation point) of the system which the
inner power supply (V_REG) works, it
becomes 1/2 V_REG (V). To remove noise,
it connects a condenser with the interval
of GND.
The signal
detection system
preamplifier
output pin
12
DC: 2.25 V
AC: −10 dBV
V_REG (4.5 V)
12
The output
impedance: About
10 Ω
It is the output pin of the signal detection
system preamplifier.
Signal input for
signal automatic
11
detection
11
DC: 2.25 V
AC: −10 dBV
20k
V_REF (2.25 V)
The entry
impedance: About
20 kΩ
It is the signal input pin for signal
automatic detection. It is possible to
adjust in the direction lowers a gain by
adding external resistance.
SDC00047AEB
15