X40430/X40431 – Preliminary Information
Low Voltage V
CC
(V1 Monitoring)
During operation, the X40430 monitors the V
CC
level
and asserts RESET if supply voltage falls below a pre-
set minimum V
TRIP1
. The RESET signal prevents the
microprocessor from operating in a power fail or
brownout condition. The RESET/RESET signal
remains active until the voltage drops below 1V. It also
remains active until V
CC
returns and exceeds V
TRIP1
for
t
PURST
.
Low Voltage V2 Monitoring
The X40430 also monitors a second voltage level and
asserts V2FAIL if the voltage falls below a preset mini-
mum V
TRIP2
. The V2FAIL signal is either ORed with
RESET to prevent the microprocessor from operating
in a power fail or brownout condition or used to inter-
rupt the microprocessor with notification of an impend-
ing power failure. The V2FAIL signal remains active
until the V2MON drops below 1V (V2MON falling). It
also remains active until V2MON returns and exceeds
V
TRIP2
by 0.2V.
Low Voltage V3 Monitoring
The X40430 also monitors a third voltage level and
asserts V3FAIL if the voltage falls below a preset mini-
mum V
TRIP3
. The V3FAIL signal is either ORed with
RESET to prevent the microprocessor from operating
in a power fail or brownout condition or used to inter-
rupt the microprocessor with notification of an impend-
ing power failure. The V3FAIL signal remains active
until the V3MON drops below 1V (V3MON falling). It
also remains active until V3MON returns and exceeds
V
TRIP3
by 0.2V.
Early Low V
CC
Detection (LOWLINE)
This CMOS output goes LOW earlier than RESET/
RESET whenever V
CC
falls below the V
TRIP1
voltage
and returns high when V
CC
exceeds the V
TRIP1
volt-
age. There is no power up delay circuitry (t
PURST
) on
this pin.
Figure 2. Two Uses of Multiple Voltage Monitoring
V2MON
X40430
Unreg.
Supply
R
R
5V
Reg
V
CC
RESET
V2MON
V2FAIL
System
Reset
Resistors selected so 3V appears on V2MON when unregulated
supply reaches 6V.
V2MON
V
CC
V3MON
X40431
Unreg.
Supply
5V
Reg
4V
Reg
3V
Reg
V
CC
RESET
V2MON
V2FAIL
V3MON
V3FAIL
System
Reset
Notice:
No external components required to monitor three voltages.
REV 1.2.3 11/28/00
www.xicor.com
Characteristics subject to change without notice.
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XICOR [ XICOR INC. ]
