AMS811 Datasheet, PDF (1/8 Pages) Advanced Monolithic Systems Ltd – Precision Monitoring of 3V, 3.3V, and 5V Power-Supply Voltages

General Description
The AMS811 / 812 are low-power microprocessor
(µP) supervisory circuits used to monitor power sup-
plies in µP and digital systems. They provide excellent
circuit reliability and low cost by eliminating external
components and adjustments when used with 5V-
powered or 3V-powered circuits. The AMS811 / 812
also provide a debounced manual reset input.
These devices perform a single function: They assert a
reset signal whenever the V_CC supply voltage falls
below a preset threshold, keeping it asserted for at
least 140ms after V_CC has risen above the reset thresh-
old. The only difference between the two devices is that
the AMS811 has an active-low RESET output (which is
guaranteed to be in the correct state for V_CC down to
1V), while the AMS812 has an active-high RESET out-
put. The reset comparator is designed to ignore fast
transients on V_CC. Reset thresholds are available for
operation with a variety of supply voltages.
Low supply current makes the AMS811 / 812 ideal
for use in portable equipment. The devices come in a
4-pin SOT143 package.
________________________Applications
Computers
Controllers
Intelligent Instruments
Critical µP and µC Power Monitoring
Portable/Battery-Powered Equipment
___________Typical Operating Circuit
V_CC
V_CC
AMS811
AMS812
RESET
MR
(RESET)
GND
V_CC
μP
RESET
INPUT
GND
PUSHBUTTON
SWITCH
( ) ARE FOR AMS812
AMS811/812
Features
♦ Precision Monitoring of 3V, 3.3V, and 5V
Power-Supply Voltages
♦ 6µA Supply Current
♦ 140ms Min Power-On Reset Pulse Width;
RESET Output (AMS811), RESET Output (AMS812)
♦ Guaranteed Over Temperature
♦ Guaranteed RESET Valid to V_CC = 1V (AMS811)
♦ Power-Supply Transient Immunity
♦ No External Components
♦ 4-Pin SOT143 Package
_______________Ordering Information
PART*
TEMP RANGE PIN-PACKAGE
AMS811_EUS-T -40°C to +85°C 4 SOT143
AMS812_EUS-T -40°C to +85°C 4 SOT143
*This part offers a choice of five different reset threshold volt-
ages. Select the letter corresponding to the desired nominal
reset threshold voltage, and insert it into the blank to complete
the part number.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
RESET THRESHOLD
SUFFIX
VOLTAGE (V)
L
4.63
M
4.38
T
3.08
S
2.93
R
2.63
___________________Pin Configuration
TOP VIEW
GND 1
4 V_CC
AMS811
AMS812
(RESET) RESET 2
3 MR
SOT143
( ) ARE FOR AMS812
NOTE: SEE LAST PAGE FOR MARKING INFORMATION.
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