3

µPC2800A

1. PIN FUNCTION

Pin

Symbol

Pin Name

Internal Equivalent Circuit

Function

No.

Power input pin

Supply a voltage of 5 V

± 10% to this

pin. If the IC malfunctions due to power

noise, connect a bypass capacitor.

2

OUT

Output pin

An open-collector output pin (active

low) with a pull-up resistor (33 k

Ω TYP.)

Connect an external pull-up resistor of

2.2 k

Ω or more, if any, to this pin.

Power output pin

Connect a capacitor of 47

µF or so to

this pin to stabilize the supply voltage to

the internal circuit.

BPF frequency

Sets the central frequency of the

setting pin

internal bandpass filter by an external

istics in CHARACTERISTIC CURVE).

Use a resistor with excellent accuracy

and temperature characteristics.

5

GND

Ground pin

GND pin

Detection

Connect a smoothing capacitor to this

capacitor

pin to obtain a DC voltage corresponding

connection pin

to the output signal level of the internal

bandpass filter.

The 0.01

µF is the most suitable value

for the external capacitor between pin 6

and GND. In case of reducing this

capacitor, confirm that the output pulses

from pin 2 have enough width even if

the longest burst signal is inputted.

3

Internal circuit

power line

4

block of BPF

Trimming

resistor

Waveform

shaping circuit

6

BPF

output signal

33 k

Ω

2

From waveform

shaping circuit

Output transistor