CM3400
Micropower, Universal Supply Voltage Supervisor (SVS)
Features
•
•
•
•
•
•
•
•
Temperature stable 1.0V trigger reference
User adjustable reset threshold
User adjustable reset delay time > 25msec
Complimentary outputs (RESET, RESET)
Integrated pull-up/down resistors
Manual reset (MR) control input
Low operating current (40µA typ.)
8-lead MSOP and SOIC package
Product Description
The CM3400 is a universal supply voltage supervisory
(SVS) controller for critical power monitoring and power
sequencing applications. During an initial power-up,
both complimentary outputs (RESET, RESET) remain
active. Once the supply voltage being monitored
exceeds the user programmed reset threshold, the out-
puts will remain active for an additional timeout interval
which is also user controlled. Both outputs become
inactive once the delay interval has expired.
The user controlled reset threshold is determined by
two external resistors as follows:
Reset Threshold [V] = (R
1
+ R
2
) / R
2
The delay time is set by an external capacitor C
T
, as
follows (where C
T
is in [nF]):
Reset Delay [ms] = (375 x C
T
[nF]) + 25 [ms]
During a brown-out condition, both outputs will immedi-
ately become active and remain active until the supply
being monitored has been restored for a period
exceeding the delay pulse. During a complete power-
down situation, both outputs will continually "hug" their
respective rails. This is achieved by the use of inte-
grated pull-up/down resistors.
The CM3400 is available in a low profile MSOP-8 and a
SOIC-8 package.
Applications
•
•
•
Critical power monitoring
Power-up sequencing
Memory integrity during "brownouts"
Typical Application Circuit
Simplified Electrical Schematic
V
DD
CM3400
R
1
+
R
2
-
C
T
GND
CT
GND
GND
C
T
1µA
V
DD
SENSE
RESET
MR
RESET
uP or
Memory
Control
MR
Falling Edge Delay
100K
V
TH
+
EN
t
DELAY
RESET
RESET
200K
SENSE
-
© 2003 California Micro Devices Corp. All rights reserved.
10/06/03
430 N. McCarthy Blvd., Milpitas, CA 95035-5112
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Tel: 408.263.3214
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Fax: 408.263.7846
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www.calmicro.com
1
CALMIRCO [ CALIFORNIA MICRO DEVICES CORP ]
