19-2535; Rev 0; 7/02
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated 碌P Reset
General Description
The MAX6439鈥揗AX6442 are a family of ultra-low-power
battery monitors with integrated microprocessor (碌P)
supervisors. The battery monitors are offered with sin-
gle or dual low-battery output options that can be used
to signal when the battery is OK (enabling full system
operation), when the battery is low (for low-power sys-
tem operation), and when the battery is dead (to dis-
able system operation). These devices also have an
independent 碌P supervisor that monitors V
CC
and pro-
vides an active-low reset output. A manual reset func-
tion is available to reset the 碌P with a push-button. No
external components are required.
The MAX6439鈥揗AX6442 are offered with several facto-
ry-trimmed low-battery threshold combinations ideal for
single-cell lithium-ion (Li+) or multicell alkaline/NiCd/
NiMH applications. When the battery voltage drops
below each specified low threshold, the low-battery out-
puts are asserted to alert the system. When the voltage
rises above the specified high thresholds, the outputs
are deasserted after a 150ms minimum timeout period,
ensuring the voltages have stabilized before power cir-
cuitry is activated or providing microprocessor reset tim-
ing. The low and high thresholds provide hysteresis in
battery-operated systems to eliminate output chattering.
The MAX6439/MAX6440 offer factory-trimmed battery
monitors with a single output. The MAX6441/MAX6442
offer factory-trimmed battery monitors with dual outputs.
All battery monitors have open-drain low-battery outputs.
The MAX6439鈥揗AX6442 monitor system voltages
(V
CC
) from 1.8V to 3.3V with seven fixed reset threshold
options. Each device is offered with two minimum reset
timeout periods of 150ms or 1200ms. The MAX6439/
MAX6441 are offered with an open-drain
RESET
output
and the MAX6440/MAX6442 are offered with a push-
pull
RESET
output.
The MAX6439鈥揗AX6442 are offered in a SOT23 pack-
age and are fully specified over a -40擄C to +85擄C temp-
erature range.
Features
o
Factory-Trimmed V
BATT
Threshold Options for
Monitoring Single-Cell Li+ or Multicell
Alkaline/NiCd/NiMH Applications
o
Immune to Short Battery Voltage Transients
o
Low Current (2.5碌A(chǔ) typ at 3.6V)
o
Single and Dual Low-Battery Output Options
o
150ms Minimum
LBO
Timeout Period
o
Independent 碌P Reset with Manual Reset
o
Factory-Set Reset Thresholds for Monitoring V
CC
from 1.8V to 3.3V
o
Available with 150ms (min) and 1.2s (min) V
CC
Reset Timeout Period Options
o
-40擄C to +85擄C Operating Temperature Range
o
Small 6- and 8-Pin SOT23 Packages
o
No External Components
MAX6439鈥揗AX6442
Ordering Information
PART
MAX6439UT_
_ _D_-T
MAX6440UT_
_ _D_-T
MAX6441KA_
_ _D_-T
MAX6442KA_
_ _D_-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
PIN-PACKAGE
6 SOT23-6
6 SOT23-6
8 SOT23-8
8 SOT23-8
Note:
The first two 鈥淿 _鈥?are placeholders for the battery moni-
tor voltage levels. Desired threshold levels are set by the part
number suffix found in Tables 1 and 2. The third 鈥淿鈥?is the V
CC
reset threshold level suffix found in Table 3. The 鈥淿鈥?after the D
is a placeholder for the reset timeout period suffix found in
Table 4. All devices are available in tape-and-reel only. There
is a 2500-piece minimum order increment for standard ver-
sions. Sample stock is typically held on standard versions only.
Nonstandard versions require a minimum order increment of
10,000 pieces. Contact factory for availability.
Applications
Battery-Powered Systems (Single-Cell Li+ or
Two-/Three-Cell NiMH, NiCd, Alkaline)
Cell Phones/Cordless Phones
Portable Medical Devices
Electronic Toys
Pagers
PDAs
MP3 Players
LBO
3
MR
2
Pin Configurations
TOP VIEW
V
BATT
1
6
V
CC
MAX6439
MAX6440
5
GND
4
RESET
SOT23-6
Pin Configurations continued at end of data sheet.
1
________________________________________________________________
Maxim Integrated Products
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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