19-2323; Rev 0; 1/02
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
General Description
The MAX6427–MAX6438 are single/dual-level battery mon-
itors 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 out-
put 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 low-
battery output is deasserted following a 140ms minimum
timeout period. The timeout period ensures that the supply
voltages have stabilized before power-converter or micro-
processor activity is enabled.
The MAX6427–MAX6438 family is available with several
monitoring options. The MAX6427/MAX6428/MAX6429
offer factory-trimmed battery-monitor thresholds, with a sin-
gle low-battery output. The MAX6430/MAX6431/MAX6432
also feature factory-trimmed thresholds, but have two low-
battery 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 out-
put 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.
Features
o
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)
o
Low Current (1µA typ)
o
Single or Dual Low-Battery Outputs
o
Push-Pull
LBO,
Open-Drain
LBO,
and Open-Drain
LBO Options
o
140ms Minimum LBO Timeout Period
o
Immune to Short Battery Voltage Transients
o
Guaranteed Valid LBO Logic State to BATT = 1.0V
o
-40°C to +85°C Operating Temperature Range
o
Small 3, 4, 5 and 6-Pin SOT Packages
o
No External Components Required
(MAX6427–MAX6432)
MAX6427–MAX6438
Ordering Information
PART
MAX6427_
_UR-T
†
The
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
3 SOT23-3
Ordering Information continued at end of data sheet.
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 “_ _”.
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 avail-
able in tape-and-reel only.
________________________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
Pin Configurations
TOP VIEW
LBO
1
(LBO)
MAX6427
MAX6428
MAX6429
BATT
2
3
GND
SOT23-3
( ) ARE FOR THE MAX6429
Typical Operating Circuit appears at end of data sheet.
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’s website at www.maxim-ic.com.
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
MAX6427–MAX6438
ABSOLUTE MAXIMUM RATINGS
BATT, V
DD
to GND ................................................-0.3V to +6.0V
HTHIN, LTHIN Inputs to GND.....................-0.3V to (V
DD
+ 0.3V)
Open-Drain
LBO/LBO, LBOH/LBOH,
LBOL/LBOL
to GND .........................................-0.3V to +6.0V
Push-Pull
LBO/LBO, LBOH/LBOH,
LBOL/LBOL
to GND ................-0.3V to (BATT or V
DD
+ 0.3V)
Input Current (all pins) ........................................................20mA
Output Current (all pins) .....................................................20mA
Continuous Power Dissipation (T
A
= +70°C)
3-Pin SOT23-3 (derate 4.0mW/°C above +70°C) .......320mW
4-Pin SOT143-4 (derate 4.0mW/°C above +70°C) .....320mW
5-Pin SOT23-5 (derate 7.1mW/°C above +70°C) .......571mW
6-Pin SOT23-6 (derate 8.7mW/°C above +70°C) .......696mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(BATT = 1.0V to 5.5V or V
DD
= 1.6V to 5.5V, T
A
= -40°C to +85°C, unless otherwise specified. Typical values are at T
A
= +25°C.)
(Note 1)
PARAMETER
Operating Voltage Range
Operating Voltage Range
BATT Supply Current
V
DD
Supply Current
SYMBOL
V
BATT
V
DD
I
BATT
I
DD
CONDITIONS
T
A
= -40°C to +85°C
T
A
= 0°C to +70°C
T
A
= -40°C to +85°C
BATT = 3.7V, no load (MAX6427–MAX6432)
V
DD
= 3.7V, no load
(MAX6433–MAX6438)
MIN
1.2
1.0
1.6
1
1
TYP
MAX
5.5
5.5
5.5
1.5
1.5
UNITS
V
V
µA
µA
FACTORY-FIXED THRESHOLDS (MAX6427–MAX6432)
HTH Threshold
(Note 2)
V
HTH
Factory-fixed options, BATT rising,
LBO deasserted when BATT rises above
V
HTH
(MAX6427/MAX6428/MAX6429)
Factory-fixed options, BATT falling,
LBO asserted when BATT falls below V
LTH
(MAX6427/MAX6428/MAX6429)
Factory-fixed options, BATT falling, LBOH
asserted when BATT falls below V
HTH-
(MAX6430/MAX6431/MAX6432)
Factory-fixed options, BATT rising,
LBOH deasserted when BATT rises above
V
HTH+
(MAX6430/MAX6431/MAX6432)
Factory-fixed options, BATT falling,
LBOL asserted when BATT falls below V
LTH-
(MAX6430/MAX6431/MAX6432)
Factory-fixed options, BATT rising,
LBOL deasserted when BATT rises above
V
LTH+
(MAX6430/MAX6431/MAX6432)
-2.5
+2.5
%
LTH Threshold
(Note 2)
V
LTH
-2.5
+2.5
%
HTH- Threshold
(Note 2)
V
HTH-
-2.5
+2.5
%
HTH+ Threshold
(Note 3)
LTH- Threshold
(Note 2)
V
HTH+
-2.5
+2.5
%
V
LTH-
-2.5
+2.5
%
LTH+ Threshold
(Note 3)
V
LTH+
-2.5
+2.5
%
2
_______________________________________________________________________________________
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
ELECTRICAL CHARACTERISTICS (continued)
(BATT = 1.0V to 5.5V or V
DD
= 1.6V to 5.5V, T
A
= -40°C to +85°C, unless otherwise specified. Typical values are at T
A
= +25°C.)
(Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX6427–MAX6438
USER-ADJUSTABLE THRESHOLDS (MAX6433–MAX638)
HTHIN Threshold
(Note 4)
User-adjustable options, HTHIN rising,
LBO is deasserted when HTHIN rises above
V
HTHIN-
, V
REF
= 615mV
(MAX6433/MAX6434/MAX6435)
User-adjustable options, LTHIN falling,
LBOH is asserted when LTHIN falls below
V
LTHIN-
, V
REF
= 615mV
(MAX6433/MAX6434/MAX6435)
User-adjustable options, HTHIN rising,
LBOH is deasserted when HTHIN rises
above V
HTHIN+
, V
REF
= 615mV
(MAX6436/MAX6437/MAX6438)
User-adjustable options, HTHIN falling,
LBOH is asserted when HTHIN falls below
V
HTHIN-
, V
REF
= 585mV
(MAX6436/MAX6437/MAX6438)
User-adjustable options, LTHIN rising,
LBOL is deasserted when LTHIN rises
above V
LTHIN+
, V
REF
= 615mV
(MAX6436/MAX6437/MAX6438)
User-adjustable options, LTHIN falling,
LBOL is asserted when LTHIN falls below
V
LTHIN-
, V
REF
= 585mV
(MAX6436/MAX6437/MAX6438)
V
HTHIN
or V
LTHIN
> 400mV
V
HTHIN
-2.5
+2.5
%
LTHIN Threshold
(Note 4)
V
LTHIN
-2.5
+2.5
%
HTHIN+ Threshold
(Note 4)
V
HTHIN+
-2.5
+2.5
%
HTHIN- Threshold
(Note 5)
V
HTHIN-
-2.5
+2.5
%
LTHIN+ Threshold
(Note 4)
V
LTHIN+
-2.5
+2.5
%
LTHIN- Threshold
(Note 5)
V
LTHIN-
-2.5
+2.5
%
HTHIN/LTHIN Leakage Current
(Note 6)
I
LKG
20
nA
_______________________________________________________________________________________
3
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
MAX6427–MAX6438
ELECTRICAL CHARACTERISTICS (continued)
(BATT = 1.0V to 5.5V or V
DD
= 1.6V to 5.5V, T
A
= -40°C to +85°C, unless otherwise specified. Typical values are at T
A
= +25°C.)
(Note 1)
PARAMETER
SYMBOL
CONDITIONS
BATT or V
DD
/HTHIN/LTHIN rising above
threshold
BATT or V
DD
/HTHIN/LTHIN falling below
threshold
BATT or V
DD
≥
1.6V, I
SINK
= 100µA,
asserted low
LBO/LBOL/LBOH
Output LOW
(Push-Pull or Open-Drain)
V
OL
BATT or V
DD
≥
2.7V, I
SINK
= 1.2mA,
asserted low
BATT or V
DD
≥
4.5V, I
SINK
= 3.2mA,
asserted low
BATT or V
DD
≥
1.6V, I
SOURCE
= 200µA,
deasserted
LBO
Output HIGH (Push-Pull
Only) (Note 7)
V
OH
BATT or V
DD
≥
2.7V, I
SOURCE
= 500µA,
deasserted
BATT or V
DD
≥
4.5V, I
SOURCE
= 800µA,
deasserted
LBO
Output Leakage Current
(Open-Drain Only)
I
LKG
LBO
deasserted
BATT or V
DD
≥
1.6V, I
SINK
= 100µA,
deasserted low
LBO/LBOL/LBOH Output
LOW (Open-Drain Only)
V
OL
BATT or V
DD
≥
2.7V, I
SINK
= 1.2mA,
deasserted low
BATT or V
DD
≥
4.5V, I
SINK
= 3.2mA,
deasserted low
LBO Output Leakage Current
(Open-Drain Only)
I
LKG
LBO asserted
0.8
×
V
SUPPLY
0.8
×
V
SUPPLY
0.8
×
V
SUPPLY
500
0.3
0.3
0.4
500
nA
V
nA
V
MIN
TYP
MAX
UNITS
LOW-BATTERY OUTPUTS (LBO, LBO,
LBOH,
LBOH,
LBOL,
LBOL )
Timeout Period
Delay
t
LBOP
t
LBOD
140
210
100
0.3
0.3
0.4
V
280
ms
µs
Note 1:
Production testing done at T
A
= +25°C, limits over temperature guaranteed by design only.
Note 2:
Percentage of selected factory-fixed HTH- or LTH- threshold voltage.
Note 3:
Percentage of 1.05
✕
(selected factory-fixed threshold voltage).
Note 4:
Percentage of 615mV voltage reference.
Note 5:
Percentage of 585mV voltage reference.
Note 6:
Guaranteed by design.
Note 7:
V
SUPPLY
is BATT or V
DD
.
4
_______________________________________________________________________________________
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
NORMALIZED LBO TIMEOUT PERIOD
vs. TEMPERATURE
MAX6427 toc01
MAX6427 toc02
MAX6427–MAX6438
SUPPLY CURRENT
vs. TEMPERATURE
1.8
V
BATT
= 5V
1.5
SUPPLY CURRENT (µA)
1.2
0.9
0.6
0.3
LBO NOT ASSERTED
0
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
0.990
-40
V
BATT
= 3.3V
1.010
NORMALIZED LBO TIMEOUT PERIOD
MAXIMUM TRANSIENT DURATION
vs. LBO COMPARATOR OVERDRIVE
OUTPUT ASSERTS
MAXIMUM TRANSIENT DURATION (µs)
MAX6427 toc03
80
1.005
60
1.000
40
V
BATT
= 2V
0.995
20
OUTPUT DOES
NOT ASSERT
0
10
100
LBO COMPARATOR OVERDRIVE (mV)
1000
-20
0
20
40
60
80
TEMPERATURE (°C)
NORMALIZED UPPER AND LOWER
TRIP VOLTAGES vs. TEMPERATURE
MAX6427 toc04
LBO OUTPUT vs. I
SINK
MAX6427 toc05
1.050
NORMALIZED TRIP VOLTAGES (V)
300
250
LBO OUTPUT (mV)
200
150
100
50
OPEN-DRAIN LBO
ASSERTED
0
2
4
6
8
1.025
LOWER TRIP VOLTAGE
1.000
UPPER TRIP VOLTAGE
0.975
0.950
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
0
10
I
SINK
(mA)
_______________________________________________________________________________________
5
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