MCP130 Microchip Technology Inc., MCP130 Datasheet - Page 4

• Manufacturer Part Number: MCP130
• Description: Microcontroller Supervisory Circuit With Open Drain Output
• Manufacturer: Microchip Technology Inc.

MCP120/130
2.0
2.1
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:
2.2
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 (V
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 F bypass
cap mounted as close as possible to the V
vides additional transient immunity.
DS11184D-page 4
V
SS
APPLICATIONS INFORMATION
The Need for Supervisory Circuits
Negative Going V
MCP120
Typical Application
RST
V
DD
Bypass
Capacitor
TRIP
V
DD
DD
- V
Microcontroller
Transients
V
RESET
MCLR
DD
or
DD
) vs. transient
V
SS
DD
pin pro-
Figure 2-2:
5V
0
0
10
Transient
Duration
8
6
4
2
0
0
Transients below
the curve will NOT
cause a reset
Typical Transient Response
1
Transients above the
curve will cause a reset
TIME
V
2
2001 Microchip Technology Inc.
TRIP
(V
- V
TRIP
T
DD
A
3
MIN
= +25°C
(V)
-
V
DD
4
)
V
V
TRIP
TRIP
MAX
MIN
5