µPC2800A
Pin
Symbol
No.
Pin Name
7
IN– First-stage gain
setting pin
8
IN+ Signal input pin
Internal Equivalent Circuit
Function
90 kΩ
ABLC
7
8
2.5 V
To limiter
circuit
Reverse input pin of the first-stage
amplifier.
Connect a capacitor (0.01 µF) to
prevent direct current so that the first-
stage amplifier operates as an AC
amplifier. The gain of the amplifier can
be adjusted by an external resistor (0 to
1 kΩ) (refer to AV vs. R1 Characteris-
tics in CHARACTERISTIC CURVE).
This pin has an internal impedance of
90 kΩ (TYP.) and can be directly
connected to a PIN photodiode.
Because this is the input pin of a high-
sensitivity amplifier, exercise care that
noise is not superimposed on this pin.
Keep the wiring length of the cathode of
the PIN photodiode as short as possi-
ble.
4