19-2625; Rev 0; 10/02
Ultra-Low-Voltage 碌P Reset Circuits and
Voltage Detectors
General Description
The MAX6841鈥揗AX6845 microprocessor (碌P) supervi-
sory circuits monitor ultra-low-voltage power supplies in
碌P and digital systems. They provide excellent circuit
reliability at low cost by eliminating external compo-
nents and adjustments when used with +0.9V to +1.5V
systems. Factory-trimmed reset thresholds are avail-
able for the MAX6841/MAX6842. The MAX6843/
MAX6844/MAX6845 provide a RESET IN input, allowing
the user to externally adjust the reset threshold. The
MAX6841鈥揗AX6845 family features a debounced man-
ual reset input (MR). The reset comparator is designed
to ignore fast transients on V
CC
.
The MAX6841鈥揗AX6845 assert a reset signal whenev-
er the V
CC
supply voltage declines below a preset or
adjustable threshold or whenever manual reset (MR) is
asserted. Reset remains asserted for a fixed timeout
delay after V
CC
has risen above the reset threshold and
when manual reset is deasserted. Five timeout periods
are available for each part: 150碌s (voltage detector ver-
sion), 1.5ms, 30ms, 210ms, and 1.68s (typ).
The MAX6841/MAX6843 have an active-low push-pull
reset output. The MAX6841/MAX6842/MAX6844 have
an active-high push-pull reset output, and the
MAX6842/MAX6845 have an active-low open-drain
reset output. The active-low open-drain reset output
requires a pullup resistor that can be connected to a
voltage from 0 to V
CC
.
The low supply current (5.7碌A(chǔ)) and small package
(SOT23-5) make the MAX6841鈥揗AX6845 ideal for use
in portable equipment.
Features
o
Factory-Set Reset Threshold Voltages for
Monitoring Supplies from 0.9V to 1.5V
(MAX6841/MAX6842)
o
Adjustable Threshold RESET IN
(MAX6843/MAX6844/MAX6845)
o
Low Power Consumption: 5.7碌A(chǔ) (typ)
o
鹵2.5% Reset Threshold Accuracy
Over Temperature
o
Five Timeout Periods: 150碌s (Voltage Detector
Version), 1.5ms, 30ms, 210ms, and 1.68s
o
Available in Three Output Configurations
Push-Pull
RESET
Push-Pull RESET
Open-Drain
RESET
o
Guaranteed Reset Valid to V
CC
= 0.55V
(Active Low)
o
Manual Reset Input
o
Immune to Short V
CC
Transients
o
Space-Saving 5-Pin SOT23 Package
MAX6841鈥揗AX6845
Ordering Information
PART
MAX6841_UKD_-T
MAX6842_UKD_-T
MAX6843UKD_-T
MAX6844UKD_-T
MAX6845UKD_-T
TEMP RANGE
-40擄C to +85擄C
-40擄C to +85擄C
-40擄C to +85擄C
-40擄C to +85擄C
-40擄C to +85擄C
PIN-PACKAGE
5 SOT23-5
5 SOT23-5
5 SOT23-5
5 SOT23-5
5 SOT23-5
Applications
Computers
Controllers
Intelligent Instruments
Critical 碌P and 碌C Power Monitoring
Portable/Battery-Powered Equipment
Telecom/Networking Equipment
Basestations
Servers/Workstations
Note:
Insert desired suffix letter (from the Threshold Suffix Guide
and the Active Timeout Period tables) into the blanks to com-
plete the part number. For example, the MAX6842GUKD1 has a
reset threshold of 1.11V and a typical reset timeout period of
1.5ms. Sample stock is generally available on standard versions
only (see the Standard Versions table). Standard versions
require a minimum order increment of 2.5k units. Nonstandard
versions must be ordered in 10k-unit increments. Contact factory
for availability. All parts are offered in tape-and-reel only.
Pin Configurations
TOP VIEW
RESET 1
GND 2
5 V
CC
RESET
1
(RESET)
GND 2
4 MR
RESET IN 3
5 V
CC
MAX6841
MAX6842
MAX6843
MAX6844
MAX6845
4 MR
Selector Guide and Typical Operating Circuit appear at end
of data sheet.
RESET 3
SOT23-5
SOT23-5
( ) ARE FOR 6844
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim鈥檚 website at www.maxim-ic.com.
Maxim
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