No. 5686-13/16

LB1821M

Continued from preceding page.

Pin No.

Pin

Functions

Equivalent circuit

11

N2

Speed discriminator count switching

Low: 0 to 1.5 V

An open state functions as a high-level input.

The hysteresis is about 0.45 V.

12

FG amplifier output (after the Schmitt circuit)

This is an open collector output.

13

FG amplifier output

This pin is connected to the FG Schmitt comparator circuit

internally in the IC.

14

FG amplifier inverting input

15

An initial reset is applied to the logic circuit block by

connecting an external capacitor (of about 0.1 µF) between

the FGIN+ pin and ground.

16 to 18

38 to 40

GND

Ground connections

These pins are all connected internally to the frame.

Continued on next page.

FG Schmitt comparator

FG reset circuit