3-Pin µP Voltage Monitor

Impala Linear Corporation

3

(408) 574-3939

www.impalalinear.com

Sept 1999

ILC803/809/810 1.5

Preliminary

V

The ILC803, ILC809 and ILC810 are relatively immune to

negative-going V

CC

glitches below the reset threshold.

Typically, a negative-going transient 125mV below the reset

threshold with a duration of 50

µs (25µs for ILC8__R/S/T) or

less will not cause an unwanted reset.

Interfacing to Bi-directional Reset Pins

The ILC803/ILC809/ILC810 can interface with

µPs with bi-

directional reset pins by connecting a 4.7k

Ω resistor in

series with the ILC803/ILC809/ILC810 output and the mP

reset pin. ILC803 connects directly with a single pull-up

resistor (figure 2).

RESET Valid to 0V

A resistor can be added from the RESET pin to ground to

0V. A 100k

Ω resistor connected from RESET to ground is

recommended. The size of the resistor should be large

enough to not load the RESET output and small enough to

pull-down any stray leakage currents.

ILC803

ILC809

µP

V

CC

V

CC

V

CC

RESET

RESET

100K

ILC803

only

100K

ILC809

only

Industry P/N

ILC Direct

Replacement

MAX803XYUR-T

ILC803YU

MAX809JEUR-T

ILC809JU

MAX809LEUR-T

ILC809LU

MAX809MEUR-T

ILC809MU

MAX809REUR-T

ILC809RU

MAX809SEUR-T

ILC809SU

MAX809TEUR-T

ILC809TU

MAX810JEUR-T

ILC810JU

MAX810LEUR-T

ILC810LU

MAX810MEUR-T

ILC810MU

MAX810REUR-T

ILC810RU

MAX810SEUR-T

ILC810SU

MAX810TEUR-T

ILC810TU

SC-70 Case

SOT-23 Case

ILC803J

QJY

QJYY

ILC803L

QLY

QLYY

ILC803M

QMY

QMYY

ILC803R

QRY

QRYY

ILC803S

QSY

QSYY

ILC803T

QTY

QTYY

ILC809J

VJY

VJYY

ILC809L

VLY

VLYY

ILC809M

VMY

VMYY

ILC809R

VRY

VRYY

ILC809S

VSY

VSYY

ILC809T

VTY

VTYY

ILC810J

ZJY

ZJYY

ILC810L

ZCY

ZCYY

ILC810M

ZMY

ZMYY

ILC810R

ZRY

ZRYY

ILC810S

ZSY

ZSYY

ILC810T

ZTY

ZTYY

Y-LOT CODE

YY-LOT CODE

3

Reset

Generator

2

1

-

+

Reset

Threshold (V)

V

CC

RESET (ILC803, ILC809

RESET (ILC810)

GND

V

TH

V

CC

RESET

Microprocessor Reset

The RESET pin is asserted whenever V

reset threshold voltage. The reset pin remains asserted for

a period of 240ms after V

CC

has risen above the reset

threshold voltage. The reset function ensures the micro-

processor is properly reset and powers up into a known

condition after a power failure. RESET will remain valid

with V

Figure 1: Timing Diagram

Figure 3: Block Diagram

Circuit Description

Alternate Source Cross Reference Guide

Device Markings Information