19-2323; Rev 2; 12/05
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
Features
The MAX6427–MAX6438 are single/dual-level battery monitors with internal hysteresis. These devices are offered with
single (MAX6427/MAX6428/MAX6429, MAX6433/
MAX6434/MAX6435) or dual (MAX6430/MAX6431/
MAX6432, MAX6436/MAX6437/MAX6438) low-battery output indicators, which can be used to indicate three battery
conditions: battery is good (operate system in normal
mode), battery is weak (operate system in low-power
mode), or battery is empty (disable the system).
These devices are ideal for monitoring single lithium-ion
(Li+) cells or multicell alkaline/NiCd/NiMH power supplies.
When the power-supply voltage drops below the specified
low threshold, the low-battery output asserts. When the
voltage rises above the specified high threshold, the lowbattery output is deasserted following a 140ms minimum
timeout period. The timeout period ensures that the supply
voltages have stabilized before power-converter or microprocessor activity is enabled.
♦ Factory-Trimmed or User-Adjustable Threshold
Options
Factory-Trimmed Low Thresholds from 1.6V to
2.1V or 2.6V to 3.1V in 100mV Increments
(MAX6427–MAX6432)
Factory-Trimmed High Thresholds from 2.3V to
2.6V or 3.3V to 3.6V in 100mV Increments
(MAX6427–MAX6432)
User-Adjustable Low/High Thresholds with
615mV Internal Reference (MAX6433–MAX6438)
♦ Low Current (1µA, typ)
♦ Single or Dual Low-Battery Outputs
♦ Push-Pull LBO, Open-Drain LBO, and Open-Drain
LBO Options
♦ 140ms Minimum LBO Timeout Period
♦ Immune to Short Battery Voltage Transients
♦ Guaranteed Valid LBO Logic State to BATT = 1.0V
♦ -40°C to +85°C Operating Temperature Range
♦ Small 3, 4, 5 and 6-Pin SOT Packages
♦ No External Components Required
(MAX6427–MAX6432)
The MAX6427–MAX6438 family is available with several
monitoring options. The MAX6427/MAX6428/MAX6429
offer factory-trimmed battery-monitor thresholds, with a single low-battery output. The MAX6430/MAX6431/MAX6432
also feature factory-trimmed thresholds, but have two lowbattery outputs.
The MAX6433–MAX6438 have user-adjustable threshold
voltages permitting the user to select the hysteresis range,
and consequently the sensitivity of the system to noise. A
wide hysteresis range also prevents chattering that can
result due to battery recovery after load removal. Single
low-battery outputs are supplied by the MAX6433/
MAX6434/MAX6435 and dual low-battery outputs by the
MAX6436/MAX6437/MAX6438.
The MAX6427–MAX6438 family is available with three output logic options for convenient interface with system
power circuitry or microprocessors. The family is offered in
small SOT23 and SOT143 packages and is fully specified
over temperature.
________________________Applications
Battery-Powered Systems (Single-Cell Li+ or
Two/Three-Cell NiMH, NiCd, Alkaline)
Cell Phones/Cordless Phones
PDAs
Electronic Toys
PART
TEMP RANGE
PIN-PACKAGE
MAX6427_ _UR-T
-40°C to +85°C
3 SOT23-3
Ordering Information continued at end of data sheet.
†The
MAX6427–MAX6432 are available with factory-trimmed
battery-monitor thresholds. Select the desired thresholds
using Tables 1 or 2 and enter the corresponding letters in
the part number by replacing “_ _”.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
Note: There are 26 standard versions with a required order
minimum of 2500 pieces. Sample stock is generally held on
the standard versions only (see Standard Versions Table).
Required order increment is 10,000 pieces for nonstandard
versions. Contact factory for availability. All devices available in tape-and-reel only.
Pin Configurations
TOP VIEW
Pagers
Portable Medical Devices
Ordering Information
MP3 Players
LBO
1
(LBO)
MAX6427
MAX6428
MAX6429
3
GND
BATT 2
SOT23-3
Typical Operating Circuit appears at end of data sheet.
( ) ARE FOR THE MAX6429.
Pin Configurations continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX6427–MAX6438
General Description
