6

FN6174.0

March 26, 2008

Pin Description

RST

its respective minimum voltage sense level.

RST

The RST output functions identically to the complementary

RST output. On the ISL88001, this is a push-pull output. On

the ISL88002, it is an open drain output that is pulled to GND

(LOW) when reset is asserted. Suggested pull-up RST

resistor values are in the range of 5k

Ω to 100kΩ.

pin is compared against an internal factory-programmed

device is initially powered up to ensure that the power supply

has stabilized. Thereafter, reset is again asserted whenever

hysteresis to help prevent chattering due to noise.

Principles of Operation

The ISL88001, ISL88002, ISL88003 devices provide a low

power, high accuracy solution for those voltage monitoring

applications needing supply voltage supervision with power

reset control. By integrating these features into small 3 Ld

SC-70 and 3 Ld SOT-23 packages and consuming as little

as 160nA of supply current, these devices can lower system

cost and reduce board space requirements.

Low Voltage Monitoring

During normal operation, the ISL88001, ISL88002,

device asserts a reset signal (RST = LOW or RST = HIGH)

to a µP/µC if this voltage is less than the preset voltage trip

point. The reset signal prevents system operation during a

power failure or brownout condition. This reset signal

Power-On Reset (POR)

Applying power to the ISL88001, ISL88002, ISL88003

(i.e. RST goes LOW). This provides several benefits:

• It prevents the system microprocessor from starting to

operate with insufficient voltage.

• It prevents the processor from operating prior to

stabilization of the oscillator.

• It ensures that the monitored device is held out of

operation until internal registers are properly loaded.

• It allows time for an FPGA to download its configuration

prior to initialization of the circuit.

RESET / RESET

Reset Output Voltage Low

0.2

0.40

V

0.2

0.40

V

0.2

0.40

V

Reset Output Voltage High

V

V

V

15

µs

POR Timeout Delay

140

200

260

ms

Load Capacitance on Reset Pin

5

pF

NOTE:

4. Parts are 100% tested at +25°C. Temperature limits established by characterization and are not production tested.

Electrical Specifications

Over the recommended operating conditions unless otherwise specified. (Continued)

SYMBOL

PARAMETER

TEST CONDITIONS

MIN

(Note 4)

TYP

MAX

(Note 4) UNITS

ISL88001

ISL88002*

FIGURE 1. TYPICAL APPLICATION DIAGRAM

GND

ISL88003

µP/µC

GND

RESET

INPUT

RESET

OUTPUT

*Necessary for ISL88002

ISL88001, ISL88002, ISL88003