ISL88015 Intersil Corporation, ISL88015 Datasheet - Page 7

• Manufacturer Part Number: ISL88015
• Description: (ISL88011 - ISL88015) 5 Ld Voltage Supervisors
• Manufacturer: Intersil Corporation

Principles of Operation
The ISL88011 through ISL88015 devices provide those
functions needed for critical voltage monitoring. These
features include Power On Reset control, customizable
supply voltage supervision, Watchdog Timer capability, and
manual reset assertion. By integrating all of these features
into a small 5 Ld SOT-23 package and using only 5.5µA of
supply current, the ISL88011 through ISL88015 devices can
assist in lowering system cost, reducing board space
requirements, and increasing the reliability of a system.
Low Voltage Monitoring
During normal operation, these supervisors monitor both the
voltage level of V
VMON (ISL88012, ISL88014, ISL88015). The device asserts
a reset if any of these voltages falls below their respective
trip points. The reset signal effectively prevents the system
from operating during a power failure or brownout condition.
This reset signal remains asserted until V
on VMON exceed their voltage threshold setting for the reset
time delay period t
RST
V
VMON
MR
RST
DD
DD
V
1V
POR
THVDD
(ISL88011, ISL88012, ISL88013) and/or
of 200ms (See Figure 1).
ISL88011, ISL88012, ISL88013, ISL88014, ISL88015
7
t
POR
FIGURE 1. VOLTAGE MONITORING TIMING DIAGRAM
DD
and the voltage
t
RPD
t
POR
The ISL88012, ISL88014 and ISL88015 allow users to
customize the minimum voltage sense level on the VMON
input pin. To do this, connect an external resistor divider
network to the VMON pin in order to set the trip point to
some voltage above 600mV according to the following
equation (See Figure 2):
V
FIGURE 2. USING VMON TO MONITOR V
INTRIP
t
RPD
V
=
V
IN
THVMON
0.6
×
R
(
-------------------------- -
R 1
1
R 2
t
R
POR
+
VMON
2
R 2
)
>t
MR
ISL88012
ISL88014
ISL88015
t
POR
IN
VIA RESISTORS
December 14, 2006
(EQ. 1)
FN8093.1