MAX6846 Datasheet, PDF (1/12 Pages) Maxim Integrated Products – Low-Power, Adjustable Battery Monitors with Hysteresis and Integrated UP Reset

19-2947; Rev 0; 7/03
Low-Power, Adjustable Battery Monitors with
Hysteresis and Integrated µP Reset
General Description
The MAX6846–MAX6849 are a family of ultra-low-power
battery monitors with integrated microprocessor (µP)
supervisors. The user-adjustable battery monitors are
offered with single 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 system operation), and when the battery is dead
(to disable system operation). These devices also have
an independent µP supervisor that monitors V_CC and
provides an active-low reset output. A manual reset
function is available to reset the µP with a pushbutton.
The MAX6846–MAX6849 are ideal for single-cell lithium-
ion (Li+) or multicell alkaline/NiCd/NiMH applications.
When the battery voltage drops below each adjusted low
threshold, the low-battery outputs are asserted to alert
the system. When the voltage rises above the adjusted
high thresholds, the outputs are deasserted after a
150ms minimum timeout period, ensuring the voltages
have stabilized before power circuitry is activated or pro-
viding microprocessor reset timing.
These devices have user-adjustable battery threshold
voltages, providing a wide hysteresis range to prevent
chattering that can result due to battery recovery after
load removal. Single low-battery outputs are supplied
by the MAX6846/MAX6847 and dual low-battery out-
puts are supplied by the MAX6848/MAX6849. All bat-
tery monitors have open-drain low-battery outputs.
The MAX6846–MAX6849 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 MAX6846/
MAX6848 are offered with an open-drain RESET output
and the MAX6847/MAX6849 are offered with a push-
pull RESET output.
The MAX6846–MAX6849 are offered in a SOT23 pack-
age and are fully specified over a -40°C to +85°C temp-
erature range.
Applications
Battery-Powered Systems (Single-Cell Li+ or
Multicell NiMH, NiCd, Alkaline)
Cell Phones/Cordless Phones
Portable Medical Devices
Digital Cameras
Pagers
PDAs
MP3 Players
Electronic Toys
Features
o User-Adjustable Thresholds for Monitoring
Single-Cell Li+ or Multicell Alkaline/NiCd/NiMH
Applications
o Single and Dual Low-Battery Output Options
o Independent µP Reset with Manual Reset
o Factory-Set Reset Thresholds for Monitoring 1.8V
to 3.3V Systems
o Available with 150ms (min) or 1.2s (min) V_CC
Reset Timeout Period Options
o 150ms (min) LBO Timeout Period
o Immune to Short-Battery Voltage Transients
o Low Current (2.5µA, typ at 3.6V)
o -40°C to +85°C Operating Temperature Range
o Small 8-Pin SOT23 Packages
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX6846KA_D_-T
-40°C to +85°C 8 SOT23-8
MAX6847KA_D_-T
-40°C to +85°C 8 SOT23-8
MAX6848KA_D_-T
-40°C to +85°C 8 SOT23-8
MAX6849KA_D_-T
-40°C to +85°C 8 SOT23-8
Note: The first “_” is the V_CC reset threshold level, suffix found
in Table 1. The “_” after the D is a placeholder for the reset
timeout period suffix found in Table 2. All devices are available
in tape-and-reel only. There is a 2500 piece minimum order
increment for standard versions (see Standard Versions table).
Sample stock is typically held on standard versions only. Non-
standard versions require a minimum order increment of
10,000 pieces. Contact factory for availability.
Pin Configurations
TOP VIEW
V_DD 1
GND 2
LTHIN 3
LBO 4
MAX6846
MAX6847
8 V_CC
7 HTHIN
6 MR
5 RESET
V_DD 1
GND 2
LTHIN 3
LBOL 4
MAX6848
MAX6849
8 V_CC
7 HTHIN
6 LBOH
5 RESET
SOT23
SOT23
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