MCP120-300DI datasheet(4/16 Pages) MICROCHIP

4 / 16 page

MCP120/130

DS11184D-page 4

 2001 Microchip Technology Inc.

2.0

APPLICATIONS INFORMATION

2.1

The Need for Supervisory Circuits

For many of today’s microcontroller applications, care

must be taken to prevent low power conditions that can

cause many different system problems. The most com-

mon causes are brown-out conditions where the sys-

tem supply drops below the operating level momentar-

ily, and the second, is when a slowly decaying power

supply causes the microcontroller to begin executing

instructions without enough voltage to sustain SRAM

and producing indeterminate results.

Figure 2-1:

Typical Application

2.2

Negative Going VDD Transients

Many system designers implementing POR circuits are

concerned about the minimum pulse width required to

cause a reset. Figure 2-2 shows typical transient

voltage below the trip point (VTRIP - VDD) vs. transient

duration. It shows that the farther below the trip point

the transient pulse goes, the duration of the pulse

required to cause a reset gets shorter. A 0.1

µF bypass

cap mounted as close as possible to the VDD pin pro-

vides additional transient immunity.

Figure 2-2:

Typical Transient Response

Microcontroller

MCLR

VSS

RST

MCP120

RESET

VSS

VDD

Bypass

Capacitor

VDD

TIME

VTRIP

MAX

VTRIP

MIN

Transient

Duration

(VTRIP

MIN

- VDD)

VTRIP - VDD (V)

TA = +25°C

Transients above the

curve will cause a reset

Transients below

the curve will NOT

cause a reset

MCP120-300DI Datasheet(PDF) 4 Page - Microchip Technology

MCP120-300DI Datasheet(HTML) 4 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Datasheet Download

Link URL