19-2535; Rev 1; 12/05
Low-Power, Single-/Dual-Level Battery Monitors
with Hysteresis and Integrated µP Reset
General Description
Features
The MAX6439–MAX6442 are a family of ultra-low-power
battery monitors with integrated microprocessor (µP)
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
♦ Factory-Trimmed V
Threshold Options for
BATT
Monitoring Single-Cell Li+ or Multicell
Alkaline/NiCd/NiMH Applications
♦ Immune to Short Battery Voltage Transients
♦ Low Current (2.5µA typ at 3.6V)
♦ Single and Dual Low-Battery Output Options
♦ 150ms Minimum LBO Timeout Period
♦ Independent µP Reset with Manual Reset
independent µP supervisor that monitors V
and pro-
CC
vides an active-low reset output. A manual reset func-
tion is available to reset the µP with a push-button. No
external components are required.
♦ Factory-Set Reset Thresholds for Monitoring V
CC
The MAX6439–MAX6442 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.
from 1.8V to 3.3V
♦ Available with 150ms (min) and 1.2s (min) V
CC
Reset Timeout Period Options
♦ -40°C to +85°C Operating Temperature Range
♦ Small 6- and 8-Pin SOT23 Packages
♦ No External Components
Ordering Information
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
6 SOT23-6
6 SOT23-6
8 SOT23-8
8 SOT23-8
MAX6439UT_ _ _D_-T
MAX6440UT_ _ _D_-T
MAX6441KA_ _ _D_-T
MAX6442KA_ _ _D_-T
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–MAX6442 monitor system voltages
Note: The first two “_ _” are placeholders for the battery moni-
(V ) from 1.8V to 3.3V with seven fixed reset threshold
CC
tor voltage levels. Desired threshold levels are set by the part
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.
number suffix found in Tables 1 and 2. The third “_” is the V
CC
reset threshold level suffix found in Table 3. The “_” 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.
The MAX6439–MAX6442 are offered in a SOT23 pack-
age and are fully specified over a -40°C to +85°C temp-
erature range.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
Applications
Pin Configurations
Battery-Powered Systems (Single-Cell Li+ or
Two-/Three-Cell NiMH, NiCd, Alkaline)
TOP VIEW
V
1
2
3
6
5
4
V
CC
BATT
MR
Cell Phones/Cordless Phones
Portable Medical Devices
Electronic Toys
Pagers
MAX6439
MAX6440
GND
LBO
RESET
PDAs
SOT23-6
MP3 Players
Pin Configurations continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.