FM1233B Fairchild Semiconductor, FM1233B Datasheet - Page 4

• Manufacturer Part Number: FM1233B
• Description: 3-Pin C Supervisor Circuit
• Manufacturer: Fairchild Semiconductor

General Description
Connecting an External Reset to the FM1233B
V
CC
The FM1233B features a highly accurate voltage reference to
which V
is compared. Once V
is below the specified
CC
CC
threshold, it will drive the RESET line and continue to hold it low
3
until V
returns above the threshold and the time for the
CC
RESET pulse duration has expired. The FM1233B is immune to
FM1233
Controller
short negative going transients on the V
line. The placement
CC
of a 0.1µF bypass capacitor as close as possible to the V
pin
CC
1
2
provides additional transient immunity.
RESET
For a V
value below 1.0V, the FM1233B does not sink very
CC
GND
much current on the RESET pin. This is not a problem in most
systems since common devices are not functional in this range.
100pF
If it is desired for the FM1233B reset to be functional below this
range, use a 100K
pull-down resistor between RESET and
PUSH
V
.
BUTTON
SS
Bi-Directional Reset
The FM1233B permits an external pushbutton to initiate a reset.
Such a connection to pin 2 will be debounced, RESET will go
low and recover in typically 250ms. For proper operation, the
external switch should be paralleled by an external capacitor of
100pF to 0.01µF.
4
www.fairchildsemi.com
FM1233B Rev. D