X40430 Datasheet, PDF (4/24 Pages) Intersil Corporation – Triple Voltage Monitor with Integrated CPU Supervisor

X40430, X40431, X40434, X40435
Low Voltage V_CC (V1 Monitoring)
During operation, the X40430, X40431, X40434,
X40435 monitors the V_CC level and asserts
RESET/RESET if supply voltage falls below a preset
minimum V_TRIP1. The RESET/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.
For the X40430 and X40431 the V2FAIL signal
remains active until the V2MON drops below 1V
(V2MON falling). It also remains active until V2MON
returns and exceeds V_TRIP2. This voltage sense cir-
cuitry monitors the power supply connected to V2MON
pin. If V_CC = 0, V2MON can still be monitored.
For the X40434 and X40435, the V2FAIL signal
remains active until V_CC drops below 1V and remains
active until V2MON returns and exceeds V_TRIP2. This
sense circuitry is powered by V_CC. If V_CC = 0, V2MON
cannot be monitored.
Low Voltage V3 Monitoring
The X40430, X40431, X40434, X40435 also monitors
a third voltage level and asserts V3FAIL if the voltage
falls below a preset minimum V_TRIP3. The V3FAIL sig-
nal is either ORed with RESET to prevent the micro-
processor from operating in a power fail or brownout
condition or used to interrupt the microprocessor with
notification of an impending 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.
This voltage sense circuitry monitors the power supply
connected to V3MON pin. If V_CC = 0, V3MON can still
be monitored.
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 voltage. There is no power-up delay circuitry
(t_PURST) on this pin.
Figure 2. Two Uses of Multiple Voltage Monitoring
V_CC
X40431-A
6-10V
5V
V_CC RESET
1M
3.3V
390K
V2MON ^V2FAIL
V3MON
(1.7V) _V3FAIL
System
Reset
Power
Fail
Interrupt
Unreg.
Supply
5V
Reg
3.0V
Reg
1.8V
Reg
V_CC
X40431-B
V_CC
RESET
V2MON
V2FAIL
V3MON
V3FAIL
System
Reset
Notice: No external components required to monitor three voltages.
4
FN8251.0
July 29, 2005