LinearVoltageRegulators Motorola Semiconductor Products, LinearVoltageRegulators Datasheet - Page 30

• Manufacturer Part Number: LinearVoltageRegulators
• Description: Analog And Interface Integratedcircuits Selector Guide & Cross Reference
• Manufacturer: Motorola Semiconductor Products

Supervisory Circuits
Overvoltage sensing circuits which drive ‘‘Crowbar’’ SCRs
are provided in several configurations from a low cost
three–terminal version to 8–pin devices which provide
Overvoltage Crowbar Sensing Circuit
MC3423P1, D
T A = 0 to +70 C, Case 626, 751
circuitry from power supply transients or
regulator failure when used with an external
‘‘Crowbar’’ SCR. The device senses
voltage and compares it to an internal 2.6 V
reference. Overvoltage trip is adjustable by
means of an external resistive voltage
divider. A minimum duration before trip is
programmable with an external capacitor.
Other features include a 300 mA high
current output for driving the gate of a
‘‘Crowbar’’
indicator output and remote activation
capability.
Over/Undervoltage Protection Circuit
MC3425P1
T A = 0 to +70 C, Case 626
supervisory circuit containing all the
necessary functions required to monitor
over and undervoltage fault conditions.
This device features dedicated over and
undervoltage
independently programmable time delays.
The overvoltage channel has a high current
drive output for use in conjunction with an
external SCR ‘‘Crowbar’’ for shutdown. The
undervoltage channel input comparator
has
programmable, and an open–collector
output for fault indication.
ANALOG AND INTERFACE INTEGRATED CIRCUITS
SELECTOR GUIDE & CROSS REFERENCE
A variety of Power Supervisory Circuits are offered.
This device can protect sensitive
The MC3425 is a power supply
hysteresis
SCR,
sensing
which
an
channels
open–collector
is
externally
with
Sense 1
Sense
Sense
2
OV
UV
3
4
2.6 V
I H
V ref
Input Section
12.5 A
pin–programmable trip voltages or additional features, such
as an indicator output drive and remote activation capability.
An over/undervoltage protection circuit is also offered.
V EE
7
200 A
V CC
200 A
Sense 2
5
DLY
UV
1
DLY
OV
200 A
3
2
Activation
Remote
Output Section
5
7
2.5 V
V ref
V CC
6
Gnd
8
Indicator
Output
MOTOROLA
OV
Drive
UV
Indicator
4
Current
Source
8
Output
59
1
6