ASM1832S PULSECORE [PulseCore Semiconductor], ASM1832S Datasheet - Page 3

• Manufacturer Part Number: ASM1832S
• Description: 3.3V ?P Power Supply Monitor and Reset Circuit
• Manufacturer: PULSECORE [PulseCore Semiconductor]

October 2006
rev 1.6
Detailed Description
The
microcontroller power supply and issues reset signals, both
active HIGH and active LOW, that halt processor operation
whenever the power supply voltage levels are outside a
predetermined tolerance.
RESET and RESET outputs
RESET and RESET signals are active for a minimum of
250ms after the supply has returned to in-tolerance level.
This allows the power supply and monitored processor to
stabilize before instruction execution is allowed to begin.
Trip Point Tolerance Selection
The TOL input is used to determine the level V
below 3.3V without asserting a reset. With TOL conected to
V
below 2.64V. RESET and RESET become active when the
V
After V
and RESET remain active for a minimum time period of
250ms. On power-down, once V
threshold RESET stays LOW and is guaranteed to be 0.4V or
less until V
ASM1832 uses a push-pull drive stage that can maintain a
valid output below 1.2V. To sink current with V
a resistor can be connected from the reset pin (RESET) to
Ground. This configuration will give a valid value on the reset
output with V
down, the configuration will draw current when the RESET is
in the high state. The value of 100KΩ should be adequate to
maintain a valid condition. The active HIGH reset signal is
valid down to a V
CC
CC
, RESET and RESET become active whenever V
falls below 2.98V if TOL is connected to ground.
CC
ASM1832
ASM1832
has risen above the trip point set by TOL, RESET
CC
CC
RESET
drops below 1.2V. The reset output on the
approaching 0V. During both power up and
CC
level of 1.2V also.
monitors
100kΩ
the
Notice: The information in this document is subject to change without notice
CC
Microprocessor
RESET
falls below the reset
3.3V µP Power Supply Monitor and Reset Circuit
microprocessor
CC
CC
below 1.2V,
can vary
CC
falls
or
.
Application Information
Manual Reset Operation
Push-button switch input, PBRST, allows the user to override
the internal trip point detection circuits and issue reset
TOL = GND
TOL = V
Tolerance
V
Figure 1: Timing Diagram : Power Up
RESET
RESET
V
Figure 2: Timing Diagram : Power Down
CC
V
CC
Select
V
CCTP
CCTP
(MAX)
(MIN)
V
CC
CCTP
t
F
V
V
OH
t
OL
RPD
Tolerance
t
R
V
V
20%
10%
CCTP
CCTP
V
CCTP
(MIN)
t
RPU
(MAX)
2.47
2.80
Min
TRIP Point Voltage
ASM1832
V
Nom
2.55
2.88
V
OH
OL
(V)
RESET
RESET
Max
2.64
2.97
3 of 9