Continued from preceding page.
Pin No.
Pin
LB1923M
Functions
Speed discriminator count switching
Low: 0 to 1.5 V
11
N2
High: 4.0 V to VCC
An open state functions as a high-level input.
The hysteresis is about 0.45 V.
VCC
Equivalent circuit
63 kΩ
200 Ω
11
VCC
12
12
FGSOUT
FG amplifier output (after the Schmitt circuit)
This is an open collector output.
VCC
FG amplifier output
13
FGOUT This pin is connected to the FG Schmitt comparator circuit
internally in the IC.
FG Schmitt comparator
VCC
20 kΩ
14
FGIN–
FG amplifier inputs
An initial reset is applied to the logic circuit block by
FG reset circuit
15
FGIN+ connecting a capacitor (of about 0.1 µF) between the FGIN+
pin and ground.
200 Ω
15
20 kΩ
13
200 Ω
14
16 to 18
38 to 40
GND
Ground connections
These pins are all connected internally to the frame.
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No. 6067-14/17