19-0541; Rev 3; 3/10
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
Features
o 1% Accurate Threshold Specified Over Full
Temperature Range
o Dual-/Triple-/Quad, Low-Battery Output Options
o Low 5.7µA Battery Current
o Open-Drain or Push-Pull Outputs
o Fixed or Adjustable Hysteresis
The MAX6782/MAX6783 offer four battery monitors in a
single package with factory-set (0.5%, 5%, 10%) or
adjustable hysteresis. The MAX6784/MAX6785 provide
three battery monitors with factory-set (0.5%, 5%, 10%)
or adjustable hysteresis. The MAX6786/MAX6787/
MAX6788 offer two battery monitors with external inputs
for setting the rising and falling thresholds, allowing
external hysteresis control. The MAX6789/MAX6790 feature quad-level overvoltage detectors with complementary outputs.
The MAX6782–MAX6790 are offered with either open-drain
or push-pull outputs. The MAX6782/MAX6784/MAX6786/
MAX6789 are available with push-pull outputs while the
MAX6783/MAX6785/MAX6787/MAX6790 are available with
open-drain outputs. The MAX6788 is available with one
open-drain output and one push-pull output (see the
Selector Guide). This family of devices is offered in spacesaving TDFN and TQFN packages and is fully specified
over the -40°C to +85°C extended temperature range.
o Low Input Bias Current
o Guaranteed Valid Low-Battery-Output Logic State
Down to VBATT = 1.05V
o Reverse-Battery Protection
o Immune to Short Battery Transients
o Fully Specified from -40°C to +85°C
o Small TDFN and TQFN Packages
Ordering Information
PART
PIN-PACKAGE
-40°C to +85°C
16 TQFN-EP*
MAX6783TE_+
-40°C to +85°C
16 TQFN-EP*
MAX6784TC_+
-40°C to +85°C
12 TQFN-EP*
MAX6785TC_+
-40°C to +85°C
12 TQFN-EP*
Ordering Information continued at end of data sheet.
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
The MAX6782/MAX6783/MAX6784/MAX6785 are available with
factory-trimmed hysteresis. Specify trim by replacing “_” with
“A” for 0.5%, “B” for 5%, or “C” for 10% hysteresis.
Applications
Battery-Powered Systems
(Single-Cell Li+ or
Multicell NiMH, NiCd,
Alkaline)
Cell Phones/Cordless
Phones
TEMP RANGE
MAX6782TE_+
Pagers
Portable Medical Devices
PDAs
Electronic Toys
MP3 Players
Pin Configuration and Typical Operating Circuit appear at
end of data sheet.
Selector Guide
MONITOR LEVEL
LBO OUTPUT
OV
OV
OUTPUT TYPE
HYSTERESIS
MAX6782TE_+
4
Quad
—
—
Push-Pull
Fixed/Adj
MAX6783TE_+
4
Quad
—
—
Open Drain
Fixed/Adj
MAX6784TC_+
3
Triple
—
—
Push-Pull
Fixed/Adj
MAX6785TC_+
3
Triple
—
—
Open Drain
Fixed/Adj
MAX6786TA+
2
Dual
—
—
Push-Pull
Adj
MAX6787TA+
2
Dual
—
—
Open Drain
Adj
MAX6788TA+
2
Dual
—
—
Push-Pull/Open Drain
Adj
MAX6789TB+
4
—
Single
Single
Push-Pull
—
MAX6790TB+
4
—
Single
Single
Open Drain
—
PART
Note: All devices are available in tape and reel in 2.5k increments. For tape and reel orders, add a “T” after the “+” to complete the part
number.
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1
MAX6782–MAX6790
General Description
The MAX6782–MAX6790 are low-power, 1% accurate,
dual-/triple-/quad-level battery monitors offered in small
TDFN and TQFN packages. These devices are ideal for
monitoring single lithium-ion (Li+) cells, or multicell alkaline/NiCd/NiMH power sources. These devices feature
fixed and adjustable hysteresis options to eliminate output chattering associated with battery-voltage monitors.
MAX6782–MAX6790
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND.)
BATT.........................................................................-0.3V to +6V
IN1–IN4, LBH1, LBL1,
LBH2, LBL2 ..................-0.3V to Min ((VBATT + 0.3V) and +6V)
HADJ1–HADJ4, REF .......-0.3V to Min ((VBATT + 0.3V) and +6V)
LBO1–LBO4 (push-pull) ..-0.3V to Min ((VBATT + 0.3V) and +6V)
LBO1–LBO4 (open drain).........................................-0.3V to +6V
Input Current (all pins) ........................................................20mA
Output Current (all pins) .....................................................20mA
Continuous Power Dissipation (TA = +70°C)
8-Pin TDFN (derate 23.8mW/°C above +70°C) ..........1905mW
10-Pin TDFN (derate 24.4mW/°C above +70°C) ........1951mW
12-Pin Thin QFN (derate 16.7mW/°C above +70°C) ..1333mW
16-Pin Thin QFN (derate 20.8mW/°C above +70°C) ..1667mW
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
Soldering Temperature (reflow) .......................................+260°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
(VBATT = 1.6V to 5.5V, TA = -40°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
Operating Voltage Range
(Note 2)
Supply Current
SYMBOL
VBATT
IQ
Startup Time (Note 3)
CONDITIONS
MIN
TYP
MAX
TA = 0°C to +70°C
1.05
5.5
TA = -40°C to +85°C
1.2
5.5
VBATT = 3.7V, no load
6.3
VBATT = 1.8V, no load
5.7
VBATT rising from 0 to 1.6V
UNITS
V
10
µA
5
ms
µA
MAX6782/MAX6783/MAX6784/MAX6785
IN_ Falling Threshold (Note 4)
VINF
IN_ Rising Threshold (Note 4)
VINR
IN_, HADJ_ Input Leakage
Current
Reference Output
0.5994
0.6055
0.6115
5% hysteresis (B version)
0.5723
0.5781
0.5839
10% hysteresis (C version)
0.5422
0.5477
0.5531
0.6024
0.6085
0.6146
V
5
nA
VIN_, VHADJ_ ≥ 0.3V
VREF
Reference Load Regulation
Reference Temperature
Coefficient
0.5% hysteresis (A version)
0.6024
IREF = 0 to 1mA
TEMPCO
Reference Short-Circuit Current
Hysteresis Adjustment Range
0.6085
VHALL
Hysteresis Adjustment Logic
High
VHALH
0.17
VTH
0.6024
V
0.3
mV/mA
15
ppm/°C
20
mA
0.4
Hysteresis Adjustment Logic Low
0.6146
V
VREF
V
0.05
V
V
MAX6786/MAX6787/MAX6788
LBL_, LBH_ Threshold
LBL_, LBH_ Input Leakage
Current
2
0.6085
VLBL, VLBH_ ≥ 0.3V
_______________________________________________________________________________________
0.6146
V
5
nA
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
MAX6782–MAX6790
ELECTRICAL CHARACTERISTICS (continued)
(VBATT = 1.6V to 5.5V, TA = -40°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX6782–MAX6788
LBO_ Propagation Delay
LBO_ Output Low Voltage (PushPull or Open Drain)
LBO_ Output High Voltage
(Push-Pull) (Note 5)
tPD
VOL
VOH
LBO_ Output Leakage Current
(Open Drain)
±100mV overdrive
30
µs
VBATT ≥ 1.2V, ISINK = 100µA
0.3
V
VBATT ≥ 2.7V, ISINK = 1.2mA
0.3
V
VBATT ≥ 4.5V, ISINK = 3.2mA
0.4
V
VBATT ≥ 1.6V, ISOURCE = 10µA
0.8 x
VBATT
V
VBATT ≥ 2.7V, ISOURCE = 500µA
0.8 x
VBATT
V
VBATT ≥ 4.5V, ISOURCE = 800µA
0.8 x
VBATT
V
Output not asserted, VLBO_ = 0 or 5V
500
nA
MAX6789/MAX6790
IN_ Rising Threshold
VTH+
0.6024
IN_ Hysteresis
0.6085
0.6146
31
VIN_ ≥ 0.3V
IN_ Input Leakage Current
OV, OV Delay Time
tPD
OV Output Low Voltage (PushPull or Open Drain)
OV Output High Voltage (PushPull) (Note 5)
VOL
VOH
OV Output Leakage Current
(Open Drain)
OV Output Low Voltage
(Push-Pull or Open Drain)
VOL
5
±100mV overdrive
30
0.3
VBATT ≥ 2.7V, ISINK = 1.2mA, output
asserted
0.3
VBATT ≥ 4.5V, ISINK = 3.2mA, output
asserted
0.4
0.8 x
VBATT
VBATT ≥ 2.7V, ISOURCE = 500µA, output not
asserted
0.8 x
VBATT
VBATT ≥ 4.5V, ISINK = 800µA, output not
asserted
0.8 x
VBATT
nA
µs
VBATT ≥ 1.6V, ISINK = 100µA, output
asserted
VBATT ≥ 1.2V, ISOURCE = 10µA, output not
asserted
V
mV
V
V
Output not asserted, VOV, VOV = 0 or 5V
500
VBATT ≥ 1.2V, ISINK = 100µA, output not
asserted
0.3
VBATT ≥ 2.7V, ISINK = 1.2mA, output not
asserted
0.3
VBATT ≥ 4.5V, ISINK = 3.2mA, output not
asserted
0.4
nA
V
_______________________________________________________________________________________
3
MAX6782–MAX6790
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
ELECTRICAL CHARACTERISTICS (continued)
(VBATT = 1.6V to 5.5V, TA = -40°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
OV Output High Voltage (PushPull ) (Note 5)
SYMBOL
VOH
OV Output Leakage Current
(Open Drain)
CONDITIONS
MIN
VBATT ≥ 1.6V, ISOURCE = 10µA, output
asserted
0.8 x
VBATT
VBATT ≥ 2.7V, ISOURCE = 500µA, output
asserted
0.8 x
VBATT
VBATT ≥ 4.5V, ISOURCE = 800µA, output
asserted
0.8 x
VBATT
VIL
CLEAR Input High Voltage
VIH
25
CLEAR Minimum Pulse Width
1
UNITS
500
nA
0.3 x
VBATT
V
0.7 x
VBATT
CLEAR Pullup Resistance
tCLD
MAX
V
Output asserted, VOV = 0 or 5V
CLEAR Input Low Voltage
CLEAR Delay Time
TYP
V
80
kΩ
µs
300
ns
Note 1: Devices are tested at TA = +25°C and guaranteed by design for TA = TMIN to TMAX as specified.
Note 2: Operating voltage range ensures low battery output is in the correct state. Minimum battery voltage for electrical specification is 1.6V.
Note 3: Reference and threshold accuracy is only guaranteed after the startup time. Startup time is guaranteed by design.
Note 4: The rising threshold is guaranteed to be higher than the falling threshold.
Note 5: The source current is the total source current from all outputs.
4
_______________________________________________________________________________________
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
PROPAGATION DELAY
vs. TEMPERATURE
6.5
6.0
5.5
VBATT = 1.8V
50
40
30
20
4.5
10
4.0
0
-40
-15
10
35
60
85
MAX6782 toc03
1000
OUTPUT ASSERTED ABOVE THIS LINE
900
800
700
600
500
400
300
200
100
0
-40
-15
10
35
60
85
1
10
1000
100
TEMPERATURE (°C)
TEMPERATURE (°C)
THRESHOLD OVERDRIVE (mV)
NORMALIZED THRESHOLD VOLTAGES
vs. TEMPERATURE (MAX6782TEA)
NORMALIZED THRESHOLD VOLTAGES
vs. TEMPERATURE (MAX6782TEB)
NORMALIZED THRESHOLD VOLTAGES
vs. TEMPERATURE (MAX6782TEC)
1.003
FALLING
1.002
1.001
1.000
0.999
0.998
0.997
RISING
1.004
1.003
1.002
1.000
0.999
0.997
0.996
0.995
10
35
TEMPERATURE (°C)
60
85
FALLING
0.998
0.995
-15
RISING
1.001
0.996
-40
NORMALIZED AT TA = +25°C
1.005
MAX6782 toc06
1.004
1.005
NORMALIZED AT TA = +25°C
1.004
NORMALIZED THRESHOLD (V)
NORMALIZED AT TA = +25°C
MAX6782 toc05
MAX6782 toc04
1.005
NORMALIZED THRESHOLD (V)
60
PROPAGATION DELAY (µs)
7.0
5.0
VIN_ = ±100mV OVERDRIVE
NORMALIZED THRESHOLD (V)
SUPPLY CURRENT (µA)
VBATT = 3.6V
MAX6782 toc02
VBATT = 5V
7.5
70
MAX6782 toc01
8.0
MAXIMUM TRANSIENT DURATION
vs. THRESHOLD OVERDRIVE
MAXIMUM TRANSIENT DURATION (µs)
SUPPLY CURRENT
vs. TEMPERATURE
1.003
1.002
RISING
1.001
1.000
0.999
0.998
FALLING
0.997
0.996
0.995
-40
-15
10
35
TEMPERATURE (°C)
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
_______________________________________________________________________________________
5
MAX6782–MAX6790
Typical Operating Characteristics
(VBATT = 3.6V, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VBATT = 3.6V, TA = +25°C, unless otherwise noted.)
0.4
0.3
VBATT = 5.0V
0.2
5.0
VBATT = 5.0V
4.5
4.0
3.5
VBATT = 3.3V
3.0
2.5
VBATT = 1.8V
2.0
0.1
6
9
12
0.608
1
2
3
0.600
-40
5
4
-15
10
35
SOURCE CURRENT (mA)
TEMPERATURE (°C)
REFERENCE VOLTAGE
vs. REFERENCE CURRENT
REFERENCE VOLTAGE
vs. SUPPLY VOLTAGE
CLEAR LATCH CIRCUIT
0.62
0.61
0.60
0.59
0.58
0.6093
IN_
5V/div
0.6092
0.6091
CLEAR
5V/div
0.6090
0.6089
0.6088
0.57
0.6087
0.56
0.6086
0.55
MAX6782TEB
0.6094
OV
5V/div
0.6085
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
REFERENCE CURRENT (mA)
85
MAX6782 toc12
0.6095
REFERENCE VOLTAGE (V)
0.63
0
60
SINK CURRENT (mA)
MAX6782TEB
0.64
0
15
0.612
MAX6782 toc11
0.65
3
MAX6782 toc10
0
0.616
0.604
1.0
0
MAX6782TEA
PUSH-PULL
VERSIONS
1.5
6
MAX6782 toc08
VBATT = 3.3V
0.620
REFERENCE VOLTAGE (V)
OUTPUT VOLTAGE (V)
0.5
5.5
OUTPUT VOLTAGE (V)
VBATT = 1.8V
MAX6782 toc07
0.6
REFERENCE VOLTAGE
vs. TEMPERATURE
LBO OUTPUT VOLTAGE HIGH
vs. SOURCE CURRENT
MAX6782 toc09
LBO OUTPUT VOLTAGE LOW
vs. SINK CURRENT
VREF (V)
MAX6782–MAX6790
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
100µs/div
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
MAX6782/MAX6783/MAX6784/MAX6785
PIN
MAX6782/
MAX6783
MAX6784/
MAX6785
NAME
1
1
IN2
Battery Monitor Input 2. Connect to an external resistive divider to set the trip
threshold for monitor 2.
2
2
IN3
Battery Monitor Input 3. Connect to an external resistive divider to set the trip
threshold for monitor 3.
3
—
IN4
Battery Monitor Input 4. Connect to an external resistive divider to set the trip
threshold for monitor 4.
4
3
REF
Reference Output. REF can source up to 1mA. REF does not require an external
bypass capacitor for stability. Keep the capacitance from REF to GND below 50pF.
HADJ1
Hysteresis Adjustment Input 1.
Connect HADJ1 to GND to select an internal preset hysteresis option.
Connect a resistive divider from REF to HADJ1 and to GND to externally adjust the
hysteresis for IN1 from its internal preset hysteresis (see Figure 6).
HADJ2
Hysteresis Adjustment Input 2.
Connect HADJ2 to GND to select an internal preset hysteresis option.
Connect a resistive divider from REF to HADJ2 and to GND to externally adjust the
hysteresis for IN2 from its internal preset hysteresis (see Figure 6).
HADJ3
Hysteresis Adjustment Input 3.
Connect HADJ3 to GND to select an internal preset hysteresis option.
Connect a resistive divider from REF to HADJ3 and to GND to externally adjust the
hysteresis for IN3 from its internal preset hysteresis (see Figure 6).
5
6
7
4
5
6
FUNCTION
8
—
HADJ4
Hysteresis Adjustment Input 4.
Connect HADJ4 to GND to select an internal preset hysteresis option.
Connect a resistive divider from REF to HADJ4 and to GND to externally adjust the
hysteresis for IN4 from its internal preset hysteresis (see Figure 6).
9
—
LBO4
Active-Low, Low-Battery Output 4. LBO4 asserts when VIN4 falls below the falling
threshold voltage. LBO4 deasserts when VIN4 exceeds the rising threshold voltage.
10
7
LBO3
Active-Low, Low-Battery Output 3. LBO3 asserts when VIN3 falls below the falling
threshold voltage. LBO3 deasserts when VIN3 exceeds the rising threshold voltage.
11
8
LBO2
Active-Low, Low-Battery Output 2. LBO2 asserts when VIN2 falls below the falling
threshold voltage. LBO2 deasserts when VIN2 exceeds the rising threshold voltage.
12
9
LBO1
Active-Low, Low-Battery Output 1. LBO1 asserts when VIN1 falls below the falling
threshold voltage. LBO1 deasserts when VIN1 exceeds the rising threshold voltage.
13
10
BATT
Battery Input. Power supply to the device. For better noise immunity, bypass BATT
to GND with a 0.1µF capacitor as close to the device as possible.
14
11
GND
Ground
15
—
N.C.
No Connection. Not internally connected.
16
12
IN1
Battery Monitor Input 1. Connect to an external resistive divider to set the trip
threshold for monitor 1.
—
—
EP
Exposed Pad. Connect EP to the ground plane. Do not use EP as the only ground
connection.
_______________________________________________________________________________________
7
MAX6782–MAX6790
Pin Description
MAX6782–MAX6790
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
Pin Description (continued)
MAX6786/MAX6787/MAX6788
PIN
NAME
1
LBL1
FUNCTION
2
LBH1
Rising Trip Level Input 1. Connect to an external resistive divider to set the rising trip level.
3
LBL2
Falling Trip Level Input 2. Connect to an external resistive divider to set the falling trip level.
4
LBH2
Rising Trip Level Input 2. Connect to an external resistive divider to set the rising trip level.
5
GND
Ground
6
LBO2
Active-Low, Low-Battery Output 2. LBO2 asserts when VLBL2 falls below the falling threshold voltage. LBO2
deasserts when VLBH2 exceeds the rising threshold voltage.
7
LBO1
Active-Low, Low-Battery Output 1. LBO1 asserts when VLBL1 falls below the falling threshold voltage. LBO1
deasserts when VLBH1 exceeds the rising threshold voltage.
8
BATT
Battery Input. Power supply to the device. For better noise immunity, bypass BATT to GND with a 0.1µF
capacitor as close to the device as possible.
—
EP
Falling Trip Level Input 1. Connect to an external resistive divider to set the falling trip level.
Exposed Pad. Connect EP to the ground plane. Do not use EP as the only ground connection.
MAX6789/MAX6790
PIN
NAME
1
IN1
Overvoltage Monitor Input 1
2
IN2
Overvoltage Monitor Input 2
3
IN3
Overvoltage Monitor Input 3
4
IN4
Overvoltage Monitor Input 4
5
GND
6
CLEAR
7
N.C.
FUNCTION
Ground
Active-Low Clear Input. OV and OV do not latch when an overvoltage fault is detected if CLEAR is held low.
CLEAR has an internal pullup resistor to BATT.
No Connection. Not internally connected.
8
OV
Active-Low Overvoltage Output. When any of the inputs (VIN_) exceeds its respective rising threshold
voltage, OV asserts and stays asserted until CLEAR is pulled low or the power to the device is cycled. OV
does not latch when an overvoltage fault is detected if CLEAR is held low.
9
OV
Active-High Overvoltage Output. Inverse of OV.
10
BATT
—
EP
Battery Input. Power supply to the device. For better noise immunity, bypass BATT to GND with a 0.1µF
capacitor as close to the device as possible.
Exposed Pad. Connect EP to the ground plane. Do not use EP as the only ground connection.
Detailed Description
The MAX6782–MAX6788 are designed to monitor two
to four battery levels (1% accuracy) and assert an
active-low output indicator when the monitored voltage
level falls below the user-set threshold. Each battery
level is associated with an independent open-drain or
push-pull output. Each of these independent outputs
can be used to provide low battery warnings at different voltage levels. Each of these monitored levels offers
fixed or adjustable hysteresis in order to prevent the
output from chattering as the battery recovers from the
8
lighter loads. The MAX6782–MAX6785 also feature reference outputs that can source up to 1mA.
The MAX6789/MAX6790 monitor four overvoltage conditions and assert the complementary overvoltage outputs when any voltage at the inputs exceeds its
respective threshold. The MAX6789/MAX6790 allow
each trip threshold to be set with external resistors.
These devices also feature a latch and a clear function.
Figures 1, 2, and 3 show the simplified block diagrams
for the MAX6782–MAX6790. See the Selector Guide.
_______________________________________________________________________________________
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
MAX6782–MAX6790
BATT
REF
IN1
COMPARATOR
SECTION 1
REFERENCE
HADJ1
LBO1
IN2
COMPARATOR
SECTION 2
HADJ2
INTERNAL
HYSTERESIS
LADDER
LBO2
IN3
COMPARATOR
SECTION 3
HADJ3
LBO3
MAX6782
MAX6783
MAX6784
MAX6785
IN4
COMPARATOR
SECTION 4
HYSTERESIS
SELECT
HADJ4
LBO4
GND
(
) MAX6782/MAX6783 ONLY
Figure 1. MAX6782–MAX6785 Block Diagram
BATT
MAX6786
MAX6787
MAX6788
REF
R1
LBO_
LBL_
RHYST
LBH_
R2
GND
Figure 2. MAX6786/MAX6787/MAX6788 Block Diagram
_______________________________________________________________________________________
9
MAX6782–MAX6790
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
BATT
IN_
MAX6789
MAX6790
REF
OV
LATCH
CONTROL
CLEAR
GND
Figure 3. MAX6789/MAX6790 Block Diagram
Low-Battery/Overvoltage Output
Hysteresis
All devices are offered with either push-pull or opendrain outputs (see the Selector Guide). The MAX6788
has one push-pull output and one open-drain output,
configured as shown in Table 1.
Input hysteresis defines two thresholds, separated by
the hysteresis voltage, configured so the output asserts
when the input falls below the falling threshold, and
deasserts only when the input rises above the rising
threshold. Figures 4 and 5 show this graphically.
Hysteresis removes, or greatly reduces, the possibility
of the output changing state in response to noise or
battery-terminal voltage recovery after load removal.
Table 1. MAX6788 Outputs
DEVICE
LBO1
LBO2
MAX6788
Push-Pull
Open Drain
All open-drain outputs require an external pullup resistor. The open-drain pullup resistor may be connected
to an external voltage up to +6V, regardless of the voltage at BATT.
10
______________________________________________________________________________________
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
MAX6782–MAX6790
VINR
INTERNAL HYSTERESIS
VINF
IN_
VHALL
VHADJ_
tPD
tPD
LBO_
A) NORMAL OPERATION FOR VHADJ_ < VHALL.
VINR
VINF
INTERNAL HYSTERESIS
IN_
VHADJ_
VHALH
tPD
tPD
LBO_
B) NORMAL OPERATION FOR VHADJ_ > VHALH.
Figure 4. MAX6782–MAX6785 Timing
______________________________________________________________________________________
11
MAX6782–MAX6790
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
VTH+
VTHIN_
CLEAR
OV
tPD
tCLD
OV
Figure 5. MAX6789/MAX6790 Timing
MAX6782–MAX6785 Hysteresis
Factory-Set Hysteresis
The MAX6782–MAX6785 have factory-set hysteresis for
ease of use and reduced external parts count. For
these devices the absolute hysteresis voltage is a percentage of the internally generated reference. The
amount depends on the device option. “A” devices
have 0.5% hysteresis, “B” devices have 5% hysteresis,
and “C” devices have 10% hysteresis. Table 2 presents
the threshold voltages for devices with factory-set hysteresis. For factory-set hysteresis, connect HADJ_ to
GND.
Table 2. Typical Falling and Rising
Thresholds for MAX6782–MAX6785
(HADJ_ = GND)
DEVICE
OPTION
PERCENT
HYSTERESIS
(%)
FALLING
THRESHOLD
(VINF) (V)
RISING
THRESHOLD
(VINR) (V)
A
0.5
0.6055
0.6085
B
5
0.5781
0.6085
C
10
0.5477
0.6085
12
Externally Adjusted Hysteresis
The MAX6782–MAX6785 can also be configured for
externally adjustable hysteresis. Connect a resistive
divider from REF to HADJ_ and to GND (Figure 6) to set
the hysteresis voltage. The hysteresis adjustment range
is from 0.4V to V REF , and the voltage at HADJ_
(V HADJ_ ) must be set higher than Hysteresis
Adjustment Logic High (VHALH) (Figure 4b). Note that if
VHADJ_ is lower than Hysteresis Adjustment Logic Low
(VHALL), these devices switch back to the internal factory-set hysteresis (Figure 4a).
MAX6786/MAX6787/MAX6788 Adjustable
Hysteresis
The MAX6786/MAX6787/MAX6788 offer external hysteresis control through the resistive divider that monitors battery voltage. Figure 2 shows the connections for external
hysteresis. See Calculating an External Hysteresis
Resistive Divider (MAX6786/MAX6787/MAX6788) section
for more information.
______________________________________________________________________________________
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
old (VINF) on the associated IN_ (the rising threshold
(VINR) is fixed). See Table 2. Calculate R3 using:
e × VREF
R3 = A
IL
where eA is the fraction of the maximum acceptable
absolute resistive divider error attributable to the input
leakage current (use 0.01 for 1%), VREF is the reference output voltage, and IL is the worst-case HADJ_
leakage current. Calculate R4 using:
Applications Information
R4 =
Resistor-Value Selection
Choosing the proper external resistors is a balance
between accuracy and power use. The input to the voltage monitor, while high impedance, draws a small current, and that current travels through the resistive
divider, introducing error. If extremely high resistor values are used, this current introduces significant error.
With extremely low resistor values, the error becomes
negligible, but the resistive divider draws more power
from the battery than necessary, and shortens battery
life. See Figure 6 and calculate the optimum value for
R1 using:
e × VBATT
R1 = A
IL
where eA is the fraction of the maximum acceptable
absolute resistive divider error attributable to the input
leakage current (use 0.01 for 1%), VBATT is the battery
voltage at which LBO should activate, and IL is the
worst-case IN_ leakage current, from the Electrical
Characteristics. For example, for 0.5% error, a 2.8V
battery minimum, and 5nA leakage, R 1 = 2.80MΩ.
Calculate R2 using:
R2 =
VINF × R1
VBATT − VINF
where VINF is the falling threshold voltage from Table 2.
Continuing the above example, and selecting VINF =
0.5477V (10% hysteresis device), R2 = 681kΩ. There
are other sources of error for the battery threshold,
including resistor and input monitor tolerances.
Calculating an External Hysteresis
Resistive Divider (MAX6782–MAX6785)
To set the hysteresis, place a resistive divider from REF
to HADJ_ as shown in Figure 6. The resistive divider
sets voltage on HADJ_, which controls the falling thresh-
VINF × R3
VREF − VINF
where VINF is the desired falling voltage threshold. To
calculate the percent hysteresis, use:
−V
V
Hysteresis (%) = 100 × INR INF
VINR
where VINR is the rising voltage.
Calculating an External
Hysteresis Resistive Divider
(MAX6786/MAX6787/MAX6788)
Setting the hysteresis externally requires calculating
three resistor values, as indicated in Figure 2. First calculate R1 using:
e × VBATT
R1 = A
IL
and R20 using:
R20 =
VTH × R1
(as in the above example)
VBATT − VTH
where R20 = R2 + RHYST determine the total resistivedivider current, ITOTAL, at the trip voltage using:
ITOTAL =
VBATT
R1 + R20
Then, determine RHYST using:
V
RHYST = HYST
ITOTAL
where VHYST is the required hysteresis voltage.
Finally, determine R2 using:
R2 = R20 - RHYST
______________________________________________________________________________________
13
MAX6782–MAX6790
Reference Output
The reference output can provide up to 1mA of output
current. The output is not buffered. Excessive loading
affects the accuracy of the thresholds. An external
capacitor is not required for stability and is stable for
capacitive loads up to 50pF. In applications where the
load or the supply can experience step changes, a
capacitor reduces the amount of overshoot (undershoot) and improves the circuit’s transient response.
Place the capacitor as close to the device as possible
for best performance.
MAX6782–MAX6790
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
Monitoring a Battery Voltage Higher
than the Allowable VBATT
Adding External Capacitance to Reduce
Noise and Transients
For monitoring higher voltages, supply a voltage to BATT,
which is within the specified supply range, and power the
input resistive divider from the high voltage to be monitored. Do not exceed the Absolute Maximum Ratings.
If monitoring voltages in a noisy environment, add a
bypass capacitor of 0.1µF from BATT to GND as close
as possible to the device. For systems with large transients, additional capacitance may be required.
Maintaining Reference Accuracy
Reverse-Battery Protection
Since the ground connection of the MAX6782–MAX6790
has a small series resistance, any current flowing into an
output flows to ground and causes a small voltage to
develop from the internal ground to GND. This has the
effect of slightly increasing the reference voltage. To minimize the effect on the reference voltage, keep the total
output sink current below 3mA.
To prevent damage to the device during a reverse-battery
condition, connect the MAX6782–MAX6785 in the configuration shown in Figure 6a or 6b. For the internal reversebattery protection to function correctly on the MAX6782–
MAX6790, several conditions must be satisfied:
• The connections to IN_/LBL_/LBH_ must be made to
the center node of a resistive divider going from
BATT to GND. The Thevenin equivalent impedance
of the resistive divider must not fall below 1kΩ in
order to limit the current.
• HADJ_ (MAX6782–MAX6785 only) must either be
connected to GND or to the center node of a resistive divider going from REF to GND.
BATT
R1
LBO_
IN_
R2
REF
• The outputs may only be connected to devices powered by the same battery as the MAX6782–
MAX6790.
MAX6782
MAX6783
MAX6784
MAX6785
Note that the MAX6782–MAX6790 will not protect other
devices in the circuit.
HADJ_
Additional Application Circuit
GND
Figure 7 shows the MAX6786/MAX6787/MAX6788 in a
typical two-battery-level monitoring circuit.
A) FACTORY PRESET HYSTERESIS CONNECTION
BATT
LBL1
1
BATT
R1
IN_
R2
REF
R3
LBO1
LBO_
MAX6782
MAX6783
MAX6784
MAX6785
LBH1
MAX6786
MAX6787
MAX6788
LBL2
HADJ_
R4
LBO2
LBH2
GND
GND
B) EXTERNAL HYSTERESIS ADJUST CONNECTION
Figure 6. Internal Preset or Externally Adjusted Hysteresis
Connection
14
Figure 7. Two-Battery-Level Monitor Configuration
______________________________________________________________________________________
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
BATT
IN1
LBO1
DEAD BATTERY
IN2
LBO2
BACKUP MEMORY
IN3
LBO3
SHUT DOWN
SUBSYSTEM
IN4
LBO4
SLOW DOWN
PROCESSOR SPEED
MAX6782
MAX6783
REF
HADJ_
Top Marks
PART
MAX6782TEA+
TOP MARK
+AEG
MAX6782TEB+
+AEH
MAX6782TEC+
+AEI
MAX6783TEA+
+AEJ
GND
Ordering Information (continued)
PART
TEMP RANGE
PIN-PACKAGE
MAX6786TA+T
-40°C to +85°C
8 TDFN-EP*
MAX6787TA+T
-40°C to +85°C
8 TDFN-EP*
MAX6788TA+T
-40°C to +85°C
8 TDFN-EP*
MAX6789TB+T
-40°C to +85°C
10 TDFN-EP*
-40°C to +85°C
10 TDFN-EP*
MAX6783TEB+
+AEK
MAX6790TB+T
MAX6783TEC+
+AEL
+Denotes a lead-free/RoHS-compliant package.
*EP = Exposed pad.
The MAX6782/MAX6783/MAX6784/MAX6785 are available with
factory-trimmed hysteresis. Specify trim by replacing “_” with
“A” for 0.5%, “B” for 5%, or “C” for 10% hysteresis.
MAX6784TCA+
+AAV
MAX6784TCB+
+AAW
MAX6784TCC+
+AAX
MAX6785TCA+
+AAY
MAX6785TCB+
+AAZ
MAX6785TCC+
+ABA
MAX6786TA+
+APU
MAX6787TA+
+APV
MAX6788TA+
+APW
MAX6789TB+
+AQI
MAX6790TB+
+AQJ
______________________________________________________________________________________
15
MAX6782–MAX6790
Typical Operating Circuit
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
LBO2
LBO3
LBO4
LBO1
LBO2
LBO3
12
11
10
9
9
8
7
HADJ4
GND 14
7
HADJ3
6
HADJ2
5
HADJ1
EP
2
3
4
1
IN2
2
BATT
LBO1
LBO2
GND
BATT
OV
OV
N.C.
CLEAR
7
6
5
10
9
8
7
6
HADJ2
MAX6789
MAX6790
3
4
1
2
LBH2
IN1
IN2
3
4
5
GND
2
IN4
1
LBL2
EP
LBH1
+
LBL1
EP
TDFN
TDFN
Package Information
Chip Information
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in
the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
PACKAGE TYPE
16
5
3
8
MAX6786
MAX6787
MAX6788
PROCESS: BiCMOS
HADJ3
THIN QFN
THIN QFN
+
6
HADJ1
EP
+
REF
IN2
1
IN1 12
IN4
+
MAX6784
MAX6785
IN3
IN1 16
GND 11
MAX6782
MAX6783
N.C. 15
BATT 10
REF
8
IN3
BATT 13
IN3
TOP VIEW
LBO1
MAX6782–MAX6790
Pin Configurations
PACKAGE CODE
DOCUMENT NO.
8 TDFN-EP
T833-3
21-0137
10 TDFN-EP
T1033-1
21-0137
12 TQFN-EP
T1233-1
21-0136
16 TQFN-EP
T1633-4
21-0136
______________________________________________________________________________________
Low-Power, 1% Accurate, Dual-/Triple-/Quad-Level
Battery Monitors in Small TDFN and TQFN Packages
REVISION
NUMBER
REVISION
DATE
DESCRIPTION
PAGES
CHANGED
0
8/06
Initial release
1
10/06
Released the MAX6784, MAX6786–MAX6790.
1, 15
—
2
5/08
Updated the Pin Description tables.
7, 8
3
3/10
Updated the Absolute Maximum Ratings and the Electrical Characteristics
table.
2
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 17
© 2010 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
MAX6782–MAX6790
Revision History
工商网监
湘ICP备2023018690号
