MAX6430PQUS-T [MAXIM]
Low-Power Single/Dual-Level Battery Monitors with Hysteresis ; 低功耗单/双级电池监控与迟滞\n
| 型号： | MAX6430PQUS-T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Low-Power Single/Dual-Level Battery Monitors with Hysteresis
|
| 文件： | 总20页 (文件大小：277K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-2323; Rev 0; 1/02
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
General Description
Features
o Factory-Trimmed or User-Adjustable Threshold
Options
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).
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)
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.
Ordering Information
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.
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 “_ _”.
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.
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)
Pin Configurations
TOP VIEW
Cell Phones/Cordless Phones
Portable Medical Devices
Electronic Toys
Pagers
LBO
1
(LBO)
PDAs
MAX6427
MAX6428
MAX6429
3
GND
MP3 Players
BATT
2
SOT23-3
( ) ARE FOR THE MAX6429
Typical Operating Circuit appears at end of data sheet.
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.
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
ABSOLUTE MAXIMUM RATINGS
BATT, V
to GND ................................................-0.3V to +6.0V
Continuous Power Dissipation (T = +70°C)
DD
A
HTHIN, LTHIN Inputs to GND.....................-0.3V to (V
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
Input Current (all pins) ........................................................20mA
Output Current (all pins) .....................................................20mA
+ 0.3V)
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
DD
+ 0.3V)
DD
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
(Note 1)
= 1.6V to 5.5V, T = -40°C to +85°C, unless otherwise specified. Typical values are at T = +25°C.)
A A
DD
PARAMETER
Operating Voltage Range
Operating Voltage Range
BATT Supply Current
SYMBOL
CONDITIONS
= -40°C to +85°C
MIN
1.2
TYP
MAX
UNITS
5.5
5.5
5.5
T
T
T
A
A
A
V
V
V
BATT
1.0
= 0°C to +70°C
V
= -40°C to +85°C
1.6
DD
I
BATT = 3.7V, no load (MAX6427–MAX6432)
= 3.7V, no load
1
1
1.5
1.5
µA
BATT
V
DD
V
Supply Current
I
µA
DD
DD
(MAX6433–MAX6438)
FACTORY-FIXED THRESHOLDS (MAX6427–MAX6432)
Factory-fixed options, BATT rising,
LBO deasserted when BATT rises above
(MAX6427/MAX6428/MAX6429)
HTH Threshold
(Note 2)
V
-2.5
-2.5
-2.5
-2.5
-2.5
-2.5
+2.5
+2.5
+2.5
+2.5
+2.5
+2.5
%
%
%
%
%
%
HTH
V
HTH
Factory-fixed options, BATT falling,
LBO asserted when BATT falls below V
(MAX6427/MAX6428/MAX6429)
LTH Threshold
(Note 2)
V
LTH
LTH
Factory-fixed options, BATT falling, LBOH
asserted when BATT falls below V
HTH-
(MAX6430/MAX6431/MAX6432)
HTH- Threshold
(Note 2)
V
HTH-
Factory-fixed options, BATT rising,
LBOH deasserted when BATT rises above
HTH+ Threshold
(Note 3)
V
HTH+
V
(MAX6430/MAX6431/MAX6432)
HTH+
Factory-fixed options, BATT falling,
LBOL asserted when BATT falls below V
(MAX6430/MAX6431/MAX6432)
LTH- Threshold
(Note 2)
V
LTH-
LTH-
Factory-fixed options, BATT rising,
LTH+ Threshold
(Note 3)
V
LBOL deasserted when BATT rises above
(MAX6430/MAX6431/MAX6432)
LTH+
V
LTH+
2
_______________________________________________________________________________________
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
ELECTRICAL CHARACTERISTICS (continued)
(BATT = 1.0V to 5.5V or V
(Note 1)
= 1.6V to 5.5V, T = -40°C to +85°C, unless otherwise specified. Typical values are at T = +25°C.)
DD
A
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
USER-ADJUSTABLE THRESHOLDS (MAX6433–MAX638)
User-adjustable options, HTHIN rising,
HTHIN Threshold
(Note 4)
LBO is deasserted when HTHIN rises above
V
-2.5
+2.5
+2.5
+2.5
+2.5
+2.5
%
HTHIN
V
, V
= 615mV
HTHIN- REF
(MAX6433/MAX6434/MAX6435)
User-adjustable options, LTHIN falling,
LBOH is asserted when LTHIN falls below
LTHIN Threshold
(Note 4)
V
-2.5
-2.5
-2.5
-2.5
-2.5
%
%
%
%
LTHIN
V
, V
= 615mV
LTHIN- REF
(MAX6433/MAX6434/MAX6435)
User-adjustable options, HTHIN rising,
LBOH is deasserted when HTHIN rises
HTHIN+ Threshold
(Note 4)
V
HTHIN+
above V
, V
= 615mV
HTHIN+ REF
(MAX6436/MAX6437/MAX6438)
User-adjustable options, HTHIN falling,
LBOH is asserted when HTHIN falls below
HTHIN- Threshold
(Note 5)
V
HTHIN-
V
, V
= 585mV
HTHIN- REF
(MAX6436/MAX6437/MAX6438)
User-adjustable options, LTHIN rising,
LBOL is deasserted when LTHIN rises
LTHIN+ Threshold
(Note 4)
V
LTHIN+
above V
, V
= 615mV
LTHIN+ REF
(MAX6436/MAX6437/MAX6438)
User-adjustable options, LTHIN falling,
LBOL is asserted when LTHIN falls below
LTHIN- Threshold
(Note 5)
V
+2.5
20
%
LTHIN-
V
, V
= 585mV
LTHIN- REF
(MAX6436/MAX6437/MAX6438)
HTHIN/LTHIN Leakage Current
(Note 6)
I
V
or V > 400mV
nA
LKG
HTHIN
LTHIN
_______________________________________________________________________________________
3
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
ELECTRICAL CHARACTERISTICS (continued)
(BATT = 1.0V to 5.5V or V
(Note 1)
= 1.6V to 5.5V, T = -40°C to +85°C, unless otherwise specified. Typical values are at T = +25°C.)
DD
A
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
LOW-BATTERY OUTPUTS (LBO, LBO, LBOH, LBOH, LBOL, LBOL )
BATT or V /HTHIN/LTHIN rising above
threshold
DD
Timeout Period
Delay
t
140
210
100
280
ms
µs
LBOP
BATT or V /HTHIN/LTHIN falling below
DD
threshold
t
LBOD
BATT or V
asserted low
≥ 1.6V, I
≥ 2.7V, I
≥ 4.5V, I
≥ 1.6V, I
≥ 2.7V, I
≥ 4.5V, I
= 100µA,
= 1.2mA,
= 3.2mA,
DD
SINK
SINK
SINK
0.3
0.3
0.4
LBO/LBOL/LBOH Output LOW
(Push-Pull or Open-Drain)
BATT or V
DD
V
V
OL
asserted low
BATT or V
DD
asserted low
BATT or V
= 200µA,
= 500µA,
= 800µA,
DD
SOURCE
SOURCE
SOURCE
0.8 × V
0.8 × V
0.8 × V
SUPPLY
SUPPLY
SUPPLY
deasserted
LBO Output HIGH (Push-Pull
Only) (Note 7)
BATT or V
DD
V
V
OH
deasserted
BATT or V
DD
deasserted
LBO deasserted
BATT or V ≥ 1.6V, I
LBO Output Leakage Current
(Open-Drain Only)
I
500
0.3
0.3
0.4
500
nA
V
LKG
= 100µA,
DD
SINK
SINK
SINK
deasserted low
LBO/LBOL/LBOH Output
LOW (Open-Drain Only)
BATT or V ≥ 2.7V, I
= 1.2mA,
DD
V
OL
deasserted low
BATT or V ≥ 4.5V, I
= 3.2mA,
DD
deasserted low
LBO Output Leakage Current
(Open-Drain Only)
I
LBO asserted
nA
LKG
Note 1: Production testing done at T = +25°C, limits over temperature guaranteed by design only.
A
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
is BATT or V
.
SUPPLY
DD
4
_______________________________________________________________________________________
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
Typical Operating Characteristics
(T = +25°C, unless otherwise noted.)
A
MAXIMUM TRANSIENT DURATION
vs. LBO COMPARATOR OVERDRIVE
NORMALIZED LBO TIMEOUT PERIOD
vs. TEMPERATURE
SUPPLY CURRENT
vs. TEMPERATURE
80
60
40
20
0
1.010
1.005
1.000
0.995
0.990
1.8
OUTPUT ASSERTS
V
= 5V
BATT
1.5
1.2
0.9
0.6
0.3
0
V
= 3.3V
BATT
V
= 2V
BATT
OUTPUT DOES
NOT ASSERT
LBO NOT ASSERTED
10
100
1000
-40
-20
0
20
40
60
80
-40
-20
0
20
40
60
80
LBO COMPARATOR OVERDRIVE (mV)
TEMPERATURE (°C)
TEMPERATURE (°C)
NORMALIZED UPPER AND LOWER
TRIP VOLTAGES vs. TEMPERATURE
LBO OUTPUT vs. I
SINK
1.050
1.025
1.000
300
250
200
150
100
50
LOWER TRIP VOLTAGE
UPPER TRIP VOLTAGE
0.975
0.950
OPEN-DRAIN LBO
ASSERTED
0
-40
-20
0
20
40
60
80
0
2
4
6
8
10
TEMPERATURE (°C)
I
(mA)
SINK
_______________________________________________________________________________________
5
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
Pin Description
PIN
MAX6427/
MAX6428/
MAX6429
MAX6430/
MAX6431/
MAX6432
MAX6433/
MAX6434/
MAX6435
MAX6436/
MAX6437/
MAX6438
NAME
FUNCTION
Low-Battery Output. LBO/LBO is asserted when BATT drops
below V
(MAX6427/MAX6428/MAX6429) or when LTHIN
LTH
LBO/
LBO
(MAX6433/MAX6434/MAX6435) drops below V
remains asserted for at least 140ms after BATT exceeds V
HTH
, and
LTHIN
1
—
4
—
(MAX6427/MAX6428/MAX6429) or V
MAX6434/MAX6435).
(MAX6433/
HTHIN
Battery-Voltage Input. Input for battery-voltage threshold
monitors and device power supply for factory-trimmed
threshold versions.
2
3
3
1
—
—
BATT
GND
2
2
Ground
Low-Battery Output High. LBOH/LBOH is asserted when BATT
drops below V (MAX6430/MAX6431/MAX6432) or when
HTH-
LBOH/
LBOH
HTHIN drops below V
remains asserted for at least 140ms after BATT exceeds V
HTH+
(MAX6430/MAX6431/MAX6432) or HTHIN rises above V
(MAX6436/MAX6437/MAX6438).
(MAX6436/MAX6437/ MAX6438). It
HTHIN-
—
—
2
4
—
—
5
4
HTHIN+
Low-Battery Output Low. LBOL/LBOL is asserted when BATT
drops below V (MAX6430/MAX6431/MAX6432) or when
LTH-
LBOL/
LBOL
LTHIN drops below V
(MAX6436/MAX6437/
LTHIN-
MAX6438). It remains asserted for at least 140ms after BATT
exceeds V
(MAX6430/MAX6431/MAX6432) or LTHIN rises
(MAX6436/MAX6437/MAX6438).
LTH+
above V
LTHIN+
HTH Threshold Monitor Input. A resistor-divider network sets
the high threshold associated with LBOH/LBOH.
—
—
—
—
—
—
1
3
5
1
3
6
HTHIN
LTHIN
LTH Threshold Monitor Input. A resistor-divider network sets
the low threshold associated with LBOL/LBOL.
V
Supply Voltage Input. Device power supply for adjustable
DD
V
DD
threshold versions.
6
_______________________________________________________________________________________
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
trimmed thresholds are ideal for monitoring single-cell
Detailed Description
Li+ or multicell alkaline/NiCd/NiMH power supplies.
The MAX6427–MAX6438 family is available with several
User-programmable versions are also available with
monitoring options. The MAX6427/MAX6428/MAX6429
thresholds determined using an external resistor-
offer factory-trimmed battery-monitor thresholds, with a
divider (see Resistor-Value Selection).The adjustable
single low-battery output (see Figure 1). The
versions can monitor down to 0.62V, making them suit-
MAX6430/MAX6431/MAX6432 also feature factory-
able for monitoring single-cell alkaline, NiMH, and NiCd
trimmed thresholds, but have two low-battery outputs
applications (V
≥ 1.6V).
DD
(see Figure 2). The factory-trimmed thresholds of the
MAX6427–MAX6432 eliminate the requirement for
external components.
When the power-supply voltage drops below the speci-
fied low threshold, the low-battery output asserts (see
Low-Battery Output). When the voltage rises above the
specified high threshold following a 140ms (min) time-
out period, the low-battery output is deasserted (see
Threshold Monitoring). This ensures the supply voltage
has stabilized before power-converter or microproces-
sor activity is enabled.
The user sets the threshold voltages for the
MAX6433–MAX6438, which permit the user to select
the hysteresis range, and consequently the sensitivity
of the system to noise. A wide hysteresis range pre-
vents chattering that can result during battery recovery
or load removal. The MAX6433/MAX6434/ MAX6435
have single low-battery outputs and the MAX6436/
MAX6437/MAX6438 have dual low-battery outputs (see
Figures 3 and 4).
Low-Battery Output
The low-battery outputs are available in active-low
(LBO, LBOH, LBOL, push-pull and open-drain) and
active-high (LBO, LBOL, LBOH, open-drain) configura-
tions. Push-pull outputs are referenced to BATT (for
The MAX6427–MAX6438 combine a 615mV reference
with two comparators, logic, and timing circuitry to pro-
vide the user with information about the charge state of
the power-supply batteries. The MAX6427–MAX6438
monitor separate high-voltage and low-voltage thresh-
olds to determine battery status. The output(s) can be
used to signal when the battery is charged, when the
battery is low, and when the battery is empty. Factory-
factory-trimmed versions) or V
old versions).
(for adjustable thresh-
DD
The open-drain devices can be pulled to a voltage inde-
pendent of V
or BATT, up to 5.5V. This allows the
DD
V
BATT
R
S
Q
Q
LBO
(LBO)
V
BATT
LBO TIMEOUT
PERIOD
615
mV
+
-
( ) ARE FOR THE MAX6429
Figure 1. MAX6427/MAX6428/MAX6429 Functional Diagram
_______________________________________________________________________________________
7
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
V
BATT
LBOL
(LBOL)
LBO
TIMEOUT
PERIOD
HYSTERESIS SWITCH
LBOH
(LBOH)
V
BATT
615
mV
+
-
HYSTERESIS SWITCH
( ) ARE FOR THE MAX6432
Figure 2. MAX6430/MAX6431/MAX6432 Functional Diagram
device to monitor and operate from direct battery voltage
while interfacing to higher voltage microprocessors.
Threshold Monitoring
The MAX6433–MAX6438 HTHIN and LTHIN inputs are
high-impedance inputs to comparators. An external resis-
tor-divider network is required between the monitored
voltage, HTHIN, LTHIN, and GND to select the desired
thresholds (see Resistor-Value Selection). The
MAX6433/MAX6434/MAX6435 single-output voltage
monitors assert LBO/LBO when LTHIN drops below the
internal LTHIN reference (615mV). LBO/LBO is deassert-
ed when HTHIN rises above the internal HTHIN reference
level (615mV) for at least 140ms (see Figure 6).
The MAX6427/MAX6428/MAX6429/MAX6433/MAX6434/
MAX6435 single-output voltage monitors provide a sin-
gle low-battery output, LBO/LBO. The MAX6427/
MAX6428/MAX6429 fixed-threshold parts assert
LBO/LBO when BATT drops below V
. The
LTH
MAX6433/MAX6434/MAX6435 adjustable-threshold
parts assert LBO/LBO when the LTHIN input drops
below the V
threshold (615mV) (see Figure 5).
LTHIN
The MAX6430/MAX6431/MAX6432/MAX6436/MAX6437/
MAX6438 dual-output voltage monitors provide two low-
battery outputs, LBOH/LBOH and LBOL/LBOL. The
MAX6430/MAX6431/MAX6432 fixed-threshold parts
The MAX6436/MAX6437/MAX6438 dual-output voltage
monitors assert LBOL/LBOL when LTHIN drops below
the LTHIN- threshold and deassert LBOL/LBOL when
LTHIN rises above the LTHIN+ threshold for at least
140ms. LBOH/LBOH is asserted when HTHIN drops
below the HTHIN- threshold and is deasserted when
HTHIN rises above the HTHIN+ threshold for at least
140ms (see Figure 7).
assert LBOH/LBOH when BATT drops below V
,
.
HTH-
and assert LBOL/LBOL when BATT drops below V
LTH-
The MAX6436/MAX6437/MAX6438 adjustable-thresh-
old parts assert LBOH/LBOH when HTHIN drops below
V
, and assert LBOL/LBOL when LTHIN drops
LTHIN-
HTHIN-
below V
(see Figure 6).
8
_______________________________________________________________________________________
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
V
BATT
V
DD
LTHIN
HTHIN
R
S
Q
Q
LBO
(LBO)
V
DD
LBO TIMEOUT
PERIOD
+
-
615
mV
EXTERNAL
RESISTOR-
DIVIDER
( ) ARE FOR THE MAX6435
Figure 3. MAX6433/MAX6434/MAX6435 Functional Diagram
Adjustable Hysteresis (MAX6433–MAX6438)
Figure 7 shows the correct connections for the external
resistor-dividers. To adjust the low-battery threshold
Hysteresis
Hysteresis increases the comparator’s noise margin by
increasing the upper threshold or decreasing the lower
threshold (see Figure 8). The hysteresis prevents the
and hysteresis connect resistor R1 between V
and
DD
LTHIN, resistor R2 between LTHIN and HTHIN, and R3
between HTHIN and GND. The hysteresis for the
MAX6433–MAX6438 is determined by an external resis-
tor-divider network (see Resistor-Value Selection sec-
tion of Applications Information). The hysteresis for the
MAX6436/MAX6437/MAX6438 is the differences
output from oscillating (chattering) when BATT or V
DD
is near the low-battery threshold. This is especially
important for applications where the load on the battery
creates significant fluctuations in battery voltages.
Fixed Hysteresis (MAX6427–MAX6432)
The MAX6427/MAX6428/MAX6429 total hysteresis is the
between V
LTHIN+
and V
(~5%) or V
and
LTHIN-
HTHIN-
(~5%).
HTHIN+
difference between the factory-trimmed V
and V
HTH.
LTH
V
For the MAX6430/MAX6431/MAX6432, the total hysteresis
is the difference between the factory-trimmed V and
HTH-
V
HTH+
or V
and V
values, approximately 5%.
LTH-
LTH+
_______________________________________________________________________________________
9
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
V
BATT
V
DD
LTHIN
HTHIN
LBOL
(LBOL)
LBO
TIMEOUT
PERIOD
HYSTERESIS SWITCH
LBOH
(LBOH)
V
BATT
615
mV
+
-
HYSTERESIS SWITCH
( ) ARE FOR THE MAX6438
Figure 4. MAX6436/MAX6437/MAX6438 Functional Diagram
V
V
HTH
V
BATT
LTH
t
t
LBOP
LBOP
LBO
Figure 5. Single Low-Battery Output Timing
10 ______________________________________________________________________________________
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
V
HTH+
V
HTH-
V
BATT
V
LTH+
V
LTH-
t
t
LBOP
LBOP
LBOL
LBOH
t
t
LBOP
LBOP
Figure 6. Dual Low-Battery Output Timing
LBO
V
V
LBO
DD
DD
R1
MAX6433
V
HTH
V
HYST
V
LTHIN
HTHIN
BATT
LBO
V
LTH
R2
R3
t
LBOP
GND
HTH = BATTERY VOLTAGE GOOD, ENABLE OPERATION.
LTH = BATTERY VOLTAGE LOW, SUSPEND/DISABLE OPERATION.
Figure 7. Adjustable Threshold Selection
Figure 8. Hysteresis
______________________________________________________________________________________ 11
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
MAX6436/MAX6437/MAX6438
Applications Information
VREF = VLTHIN- = VHTHIN- = 585mV
Resistor-Value Selection (Programming
the Adjustable Thresholds)
R1 + R2 + R3
VTRIPLOW = VLTH- = V
REF
MAX6433/MAX6434/MAX6435
R2 + R3
R1 + R2 + R3
VTRIPHIGH = VHTL- = V
V
= V
= V
= 615mV
REF
REF
LTHIN
HTHIN
R3
R1 + R2 + R3
R2 + R3
RTOTAL = R1 + R2 + R3
V
= V
= V
TRIPLOW
LTH REF
R1 + R2 + R3
Use the following steps to determine values for R1, R2,
and R3 of Figure 8.
V
= V
= V
TRIPHIGH
HTL REF
R3
1) Choose a value for R
, the sum of R1, R2, and
R
= R1 + R2 + R3
TOTAL
TOTAL
R3. Because the MAX6436/MAX6437/MAX6438
Use the following steps to determine values for R1, R2,
and R3 of Figure 8.
have very high input impedances, R
up to 5MΩ.
can be
TOTAL
1) Choose a value for R
, the sum of R1, R2, and
2) Calculate R3 based on R
upper trip point:
and the desired
TOTAL
TOTAL
R3. Because the MAX6433/MAX6434/MAX6435
have very high input impedances, R
up to 5MΩ.
2) Calculate R3 based on R
upper trip point:
can be
TOTAL
V
× R
615mV × R
TOTAL
REF
TOTAL
R3 =
=
and the desired
TOTAL
V
V
TRIPHIGH
TRIPHIGH
3) Calculate R2 based on R
desired lower trip point:
, R3, and the
TOTAL
V
× R
615mV × R
TOTAL
REF
V
TOTAL
R3 =
=
V
TRIPHIGH
TRIPHIGH
615mV ×R
TOTAL
−R3
V
3) Calculate R2 based on R
desired lower trip point:
, R3, and the
TOTAL
TRIPLOW
4) Calculate R1 based on R
, R3, and R2:
TOTAL
615mV × R
TOTAL
R2 =
− R3
R1 = R
− R2 − R3
TOTAL
V
TRIPLOW
V
= V
✕ 1.05, V
= V
✕ 1.05
HTH+
HTH-
LTH+
LTH-
4) Calculate R1 based on R
, R3, and R2:
TOTAL
DC-to-DC Converter Application
R1 = R
− R2 − R3
TOTAL
The MAX6430/MAX6431/MAX6432 and MAX6436/
MAX6437/MAX6438 dual-output battery monitors can
be used in conjunction with a step-up DC-to-DC con-
verter to power 5V microprocessor systems using a sin-
gle Li+ cell or two to three alkaline/NiCd/NiMH cells
(Figure 9). The LBOH output indicates that the battery
voltage is weak, and is used to warn the microproces-
sor of potential problems. Armed with this information
the microprocessor can reduce system power con-
sumption. The LBOL output indicates the battery is
empty, and system power should be disabled. By con-
necting LBOL to the SHDN pin of the DC-to-DC con-
verter, power to the microprocessor is removed.
Microprocessor power will not return until the battery has
recharged to a voltage greater than HTH+ (Figure 6).
IN
OUT
V
V
BATT
CC
DC/DC
BATT
MAX6431
LBOL
SHDN
µP
LBOH
NMI
GND
GND
Figure 9. DC-to-DC Converter Application
12 ______________________________________________________________________________________
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
useful in determining which system resources can be
powered by the battery at the current charge state.
Li+ Battery Charger Application
The MAX6430/MAX6431/MAX6432 and MAX6436/
MAX6437/MAX6438 dual-output battery monitors can
be used in conjunction with a battery charger to pro-
vide a system with additional information about the bat-
tery charge state (Figure 10). Many battery chargers,
such as the MAX1879, provide the user with a CHG
output, which tells the system that the battery is
charged. The MAX6430/MAX6431/MAX6432 and
MAX6436/MAX6437/MAX6438 dual-output battery mon-
itors provide two outputs, which can be used to relay
the battery condition to the system. This information is
CURRENT-
LIMITED
AC WALL
ADAPTER
LED
GATE
BATT
IN
V
CHG
BATT
LBOL
LBOH
1-CELL
Li+
BATTERY
MAX1879
MAX6430
PULSE-WIDTH
SELECT INPUT
TSEL
GND
THERM
ADJ
GND
THERMISTOR
Figure 10. Lithium-Ion Cell Charger Application (using MAX1879)
Typical Operating Circuit
V
V
BATT
CC
BATT
µP
MAX6427
NMI
LBO
______________________________________________________________________________________ 13
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
Ordering Information (continued)
Pin Configurations (continued)
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
3 SOT23-3
3 SOT23-3
4 SOT143-4
4 SOT143-4
4 SOT143-4
5 SOT23-5
5 SOT23-5
5 SOT23-5
6 SOT23-6
6 SOT23-6
6 SOT23-6
MAX6428_ _UR-T
MAX6429_ _UR-T
MAX6430_ _US-T
MAX6431_ _US-T
MAX6432_ _US-T
MAX6433UK-T
MAX6434UK-T
MAX6435UK-T
MAX6436UT-T
MAX6437UT-T
MAX6438UT-T
LBOL
4
(LBOL)
BATT
GND
1
MAX6430
MAX6431
MAX6432
LBOH
(LBOH)
2
3
SOT143-4
†
The MAX6427–MAX6432 are available with factory-trimmed
( ) ARE FOR THE MAX6432
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.
HTHIN
GND
1
2
3
5
4
V
DD
MAX6433
MAX6434
MAX6435
LTHIN
LBO
(LBO)
Chip Information
TRANSISTOR COUNT: 905
SOT23-5
( ) ARE FOR THE MAX6435
PROCESS TECHNOLOGY: BiCMOS
HTHIN
GND
1
2
3
6
5
4
V
DD
MAX6436
MAX6437
MAX6438
LBOH
(LBOH)
LTHIN
LBOL
(LBOL)
SOT23-6
( ) ARE FOR THE MAX6438
14 ______________________________________________________________________________________
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
Table 1. Factory-Trimmed Lower and Upper Threshold Combinations for Single-Cell Li+
or Three-Cell Alkaline/NiCd/NiMH Applications (MAX6427–MAX6432)
UPPER THRESHOLD (HTH/HTH-)
VOLTAGES
2.6V
3.3V
AG
BG
CG
DG
EG
3.4V
AH
BH
CH
DH
EH
3.5V
AI
3.6V
AJ
BI
BJ
2.7V
CI
CJ
DJ
EJ
2.8V
DI
2.9V
EI
3.0V
3.1V
FG
FH
FI
FJ
Table 2. Factory-Trimmed Lower and Upper Threshold Combinations for Two-Cell
Alkaline/NiCd/NiMH Applications (MAX6427–MAX6432)
UPPER THRESHOLD (HTH/HTH-)
VOLTAGES
1.6V
2.3V
KQ
LQ
2.4V
KR
LR
2.5V
KS
2.6V
KT
1.7V
LS
LT
1.8V
MQ
NQ
OQ
PQ
MR
NR
OR
PR
MS
NS
OS
PS
MT
NT
OT
PT
1.9V
2.0V
2.1V
Standard Versions
PART
TOP MARK
KAEL
PART
TOP MARK
FZKZ
FZLA
MAX6430MR
MAX6430OR
MAX6431DH
MAX6431EH
MAX6431EI
MAX6431MR
MAX6431OR
MAX6433UK
MAX6434UK
MAX6435UK
MAX6436UT
MAX6437UT
MAX6438UT
MAX6427DH
KAEM
KAES
KAET
MAX6427EH
MAX6427EI
MAX6427MR
MAX6427OR
MAX6428DH
MAX6428EH
MAX6428EI
MAX6428MR
MAX6428OR
MAX6430DH
MAX6430EH
MAX6430EI
FZLB
FZLF
KAEU
KAEN
KAEO
ADVH
ADVI
FZLG
FZLC
FZLD
FZLE
FZLH
FZLI
ADVJ
ABAB
ABAC
ABAD
KAEP
KAEQ
KAER
______________________________________________________________________________________ 15
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
Selector Guide
ACTIVE-
LOW PUSH-
PULL
ACTIVE-
LOW OPEN-
DRAIN
ACTIVE-
HIGH OPEN-
DRAIN
FACTORY-
FIXED
THRESHOLDS
USER-
ADJUSTABLE
THRESHOLDS
SINGLE
OUTPUT
DUAL
OUTPUT
PART
OUTPUT
OUTPUT
OUTPUT
MAX6427
MAX6428
MAX6429
MAX6430
MAX6431
MAX6432
MAX6433
MAX6434
MAX6435
MAX6436
MAX6437
MAX6438
ꢀ
ꢀ
—
—
—
—
—
—
ꢀ
ꢀ
—
—
ꢀ
—
ꢀ
—
—
ꢀ
ꢀ
ꢀ
—
—
—
ꢀ
ꢀ
—
—
ꢀ
ꢀ
ꢀ
—
—
ꢀ
—
—
—
ꢀ
ꢀ
—
—
ꢀ
ꢀ
ꢀ
—
—
ꢀ
ꢀ
—
—
—
—
—
—
—
—
ꢀ
—
—
—
ꢀ
ꢀ
—
—
ꢀ
ꢀ
ꢀ
—
—
ꢀ
ꢀ
ꢀ
—
—
ꢀ
—
—
—
ꢀ
—
—
ꢀ
ꢀ
—
ꢀ
16 ______________________________________________________________________________________
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
Package Information
______________________________________________________________________________________ 17
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
Package Information (continued)
18 ______________________________________________________________________________________
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
Package Information (continued)
______________________________________________________________________________________ 19
Low-Power, Single/Dual-Level Battery Monitors
with Hysteresis
Package Information (continued)
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
20 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2002 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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