MAX4373FESA+ [MAXIM]
Low-Cost, Micropower, High-Side Current-Sense Amplifier Comparator Reference ICs;
| 型号： | MAX4373FESA+ |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Low-Cost, Micropower, High-Side Current-Sense Amplifier Comparator Reference ICs |
| 文件： | 总13页 (文件大小：300K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
EVALUATION KIT AVAILABLE
Low-Cost, Micropower, High-Side
Current-Sense Amplifier +
MAX4373/MAX4374/MAX4375
General Description
Comparator + Reference ICs
Benefits and Features
The MAX4373/MAX4374/MAX4375 low-cost, micropow-
er, high-side current-sense supervisors contain a high-
side current-sense amplifier, bandgap reference, and
comparator with latching output. They feature a voltage
output that eliminates the need for gain-setting resistors,
making them ideal for today’s notebook computers, cell
phones, and other systems where battery/DC current
monitoring is critical. High-side current monitoring is
especially useful in battery-powered systems since it
does not interfere with the ground path of the battery
charger. The 0 to +28V input common-mode range is
independent of the supply voltage, which ensures that
the current-sense feedback remains viable even when
connected to a battery pack in deep discharge.
• Integrated Current-Sensing Solution Simplifies High-
Side Current Monitoring
• Current-Sense Amplifier plus Internal Comparator
and Bandgap Reference with Improved Accuracy
• 1mV (max) Input Offset Voltage
• 2% (max) Full-Scale Accuracy
• Internal Bandgap Reference ( 1ꢀ.% Accuracy)
• High Accuracy +2V to +28V Common-Mode Range,
Functional Down to 0V, Independent of Supply
Voltage Ensures Current Monitoring Even In Deep
Discharge of Battery Pack
• Low Power Consumption Extends Battery Life
• 50µA Supply Current
• Single +2ꢀ7V to +28V Operating Supply
The comparator output of the MAX4373/MAX4374/
MAX4375 is latched to provide a turn-off flag that
doesn’t oscillate. In addition, the MAX4374/MAX4375
contain a second comparator for use in window-detec-
tion functions. The MAX4373/MAX4374/MAX4375 are
available in three different gain versions (T = +20V/V,
F = +50V/V, H = +100V/V) and use an external sense
resistor to set the sensitivity of the input voltage to the
load current. These features offer a high level of inte-
gration, resulting in a simple and compact current-
sense solution.
• Latching Comparator Output Eliminates Oscillation
• Three Gain Versions (+20V/V, +50V/V,
+100V/V) Support Different Size Battery Packs
Ordering Information
PIN-
PACKAGE
GAIN
(V/V)
PART
TEMP RANGE
MAX4373TEUA+ -40°C to +85°C 8 µMAX
MAX4373TESA+ -40°C to +85°C 8 SO
MAX4373FEUA+ -40°C to +85°C 8 µMAX
MAX4373FESA+ -40°C to +85°C 8 SO
MAX4373HEUA+ -40°C to +85°C 8 µMAX
MAX4373HESA+ -40°C to +85°C 8 SO
+20
+20
The MAX4373/MAX4374/MAX4375 operate from a sin-
gle +2.7V to +28V supply and consume 50µA. They are
specified for the extended operating temperature range
(-40°C to +85°C) and are available in 8-pin and 10-pin
µMAX® packages.
+50
+50
+100
+100
+Denotes a lead(Pb)-free/RoHS-compliant package.
Ordering Information continued at end of data sheet.
Applications
Notebook Computers
Typical Operating Circuit
Portable/Battery-Powered Systems
Smart Battery Packs/Chargers
Cell Phones
I
LOAD
+ V
SENSE
-
V
= 0 TO 28V
IN
R
SENSE
LOAD/
BATTERY
RS+
RS-
Power-Management Systems
General-System/Board-Level Current Monitoring
Precision Current Sources
V
CC
V
= 2.7V TO 28V
CC
C1
0.1µF
MAX4373
OUT
CIN
V
PULL-UP
R1
R2
(UP TO 5V)
R3
COUT
RESET
µMAX is a registered trademark of Maxim Integrated Products, Inc.
GND
Pin Configurations appear at end of data sheet.
19-1630; Rev 5; 5/15
Low-Cost, Micropower, High-Side
Current-Sense Amplifier +
MAX4373/MAX4374/MAX4375
Comparator + Reference ICs
Absolute Maximum Ratings
V
CC
, RS+, RS- to GND ...........................................-0.3V to +30V
Continuous Power Dissipation (T = +70°C)
A
OUT to GND ................................................-0.3V to the lesser of
(V + 0.3V) or +15V
8-Pin µMAX (derate 4.1mW/°C above +70°C).............330mW
8-Pin SO (derate 5.9mW/°C above +70°C)..................471mW
10-Pin µMAX (derate 5.6mW/°C above +70°C)...........444mW
14-Pin SO (derate 8.3mW/°C above +70°C)................667mW
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
CC
CIN1, CIN2, RESET to GND ........................-0.3V to the lesser of
(V + 0.3V) or +12V
CC
Differential Input Voltage (V + - V -).............................. 0.3V
RS
RS
COUT1, COUT2 to GND........................................-0.3V to +6.0V
Current into Any Pin.......................................................... 10mA
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
(V
= +2.7V to +28V, V
= 0 to +28V, V
= 0V, V
= 0V, R
= 1MΩ, T = T
to T
, unless otherwise noted.
MAX
CC
RS+
SENSE
RESET
LOAD
A
MIN
Typical values are at T = +25°C.) (Note 1)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Operating Voltage Range
(Note 2)
V
2.7
0
28
V
CC
Common-Mode Input Range
(Note 3)
V
CMR
28
V
Common-Mode Rejection
Supply Current
CMR
V
V
V
V
V
V
V
> 2V
85
dB
µA
µA
RS+
I
> 2V, V
= 5mV
SENSE
50
100
0.5
2.5
2.0
4
CC
RS+
Leakage Current
I
I
= 0V, V = 28V
RS+
0.015
RS+, RS-
CC
> 2V
≤ 2V
> 2V
≤ 2V
0
RS+
RS+
RS+
RS+
I
RS+
-25
0
Input Bias Current
µA
I
RS-
-50
150
100
4
Gain = +20V/V, +50V/V, V
= 12V
170
120
0.1
RS+
Full-Scale Sense Voltage
(Note 4)
V
mV
mV
SENSE
Gain = +100V/V, V
= 12V
RS+
T = +25°C
A
1
2
2
3
2
3
V
CC
= V
= 12V
RS+
Input Offset Voltage
V
OS
(Note 11)
T = T
A
to T
MAX
MIN
T = +25°C
A
0.30
0.35
V
CC
= 12V,
V
RS+
= 12V
T = T
to T
A
MIN
MAX
V
=
SENSE
100mV
(Note 6)
T = +25°C
A
V
CC
= 28V,
Total OUT Voltage Error
(Note 5)
V
RS+
= 28V
V
OUT
T = T to T
A MIN
%
MAX
V
CC
= 12V, V
= 0.1V
5.0
5.0
RS+
V
V
= 6.25mV, V
= 12V,
CC
SENSE
= 12V (Note 7)
RS+
I
I
= 10µA
2.5
8.5
OUT
V
V
= 2.7V,
CC
OUT Voltage Low
OUT Voltage High
V
V
mV
V
OUT
= 12V
RS+
= 100µA
65
OUT
CC -
V
CC
= 2.7V, I
= -500µA, V = 12V
RS+
0.25
OUT
V
OH
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Maxim Integrated | 2
Low-Cost, Micropower, High-Side
Current-Sense Amplifier +
MAX4373/MAX4374/MAX4375
Comparator + Reference ICs
Electrical Characteristics (continued)
(V
= +2.7V to +28V, V
= 0 to +28V, V
= 0V, V
= 0V, R
= 1MΩ, T = T
to T
, unless otherwise noted.
MAX
CC
RS+
SENSE
RESET
LOAD
A
MIN
Typical values are at T = +25°C.) (Note 1)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V
= 100mV,
SENSE
200
120
110
Gain = +20V/V
V
= 100mV,
SENSE
Gain = +50V/V
-3dB Bandwidth
BW
kHz
V
V
= 12V,
= 12V,
RS+
CC
V
SENSE
Gain = +100V/V
= 100mV,
C
LOAD
= 10pF
V
= 6.25mV
50
SENSE
MAX437_T
MAX437_F
MAX437_H
+20
+50
+100
Gain
A
V/V
%
V
V
=
SENSE
T
= +25°C
0.3
1.7
2.7
1.7
2.7
A
A
A
A
20mV to 150mV;
= 12V; V
V
CC
=
RS+
T
T
T
= -40°C to +85°C
= +25°C
12V; Gain = 20, 50
Gain Accuracy
ΔA
V
V
=
SENSE
0.3
20mV to 100mV,
= 12V, V
V
CC
=
RS+
= -40°C to +85°C
= 6.25mV to
12V, Gain = 100
V
Gain = +20V/V,
SENSE
20
20
100mV
V
V
= 12V,
OUT Settling Time to 1% of
Final Value
CC
µs
= 12V,
RS+
V
= 100mV to
SENSE
C
LOAD
= 10pF
6.25mV
Capacitive Load Stability
OUT Output Resistance
Power-Supply Rejection
No sustained oscillations
1000
1.5
pF
Ω
R
V
V
= 100mV
OUT
SENSE
PSR
= 2V, V
> 2V
72
87
dB
OUT
RS+
V
V
= 100mV, C
= 10pF,
LOAD
Power-Up Time to 1% of Final
Value
SENSE
0.5
0.1
ms
ms
= 12V, V
= 12V
CC
RS+
Saturation Recovery Time
(Note 8)
V
CC
= 12V, V
= 12V, C
= 10pF
RS+
LOAD
COMPARATOR (Note 9)
T
T
= +25°C
590
586
600
610
614
A
Comparator Threshold
V
V
mV
TH
= T
to T
MAX
MIN
A
Comparator Hysteresis
Input Bias Current
-9
mV
nA
I
B
2.2
15
C = 10pF, R = 10kΩ pull-up to 5V,
5mV of overdrive
L
L
Propagation Delay
Output Low Voltage
4
µs
V
I
= 1mA
0.6
OL
SINK
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Maxim Integrated | 3
Low-Cost, Micropower, High-Side
Current-Sense Amplifier +
MAX4373/MAX4374/MAX4375
Comparator + Reference ICs
Electrical Characteristics (continued)
(V
= +2.7V to +28V, V
= 0 to +28V, V
= 0V, V
= 0V, R
= 1MΩ, T = T
to T
, unless otherwise noted.
MAX
CC
RS+
SENSE
RESET
LOAD
A
MIN
Typical values are at T = +25°C.) (Note 1)
A
MIN
TYP
MAX
UNITS
µA
V
PARAMETER
SYMBOL
CONDITIONS
= 5V (Note 10)
PULL-UP
1
Output High Leakage Current
RESET Input High Voltage
RESET Input Low Voltage
Logic Input Current
V
= 28V, V
CC
2.0
V
IH
0.8
0.5
V
V
IL
-0.5
µA
µs
I , I
IL IH
V
IL
= 0, V = 5.5V, V
= 28V
CC
IH
1.5
3
t
Minimum RESET Pulse Width
RESET Propagation Delay
RPW
µs
t
RPD
Note 1: All devices are 100% production tested at T = +25°C. All temperature limits are guaranteed by design.
A
Note 2: Guaranteed by PSR test.
Note 3: Guaranteed by OUT Voltage Error test.
Note 4: Guaranteed by Gain Accuracy test. Output voltage is internally clamped not to exceed 12V.
Note 5: Total OUT Voltage Error and Full-Scale Accuracy are the sum of gain and offset voltage errors.
Note 6: Measured at I
= -500µA (R
= 4kΩ for gain of +20V/V, R
= 10kΩ for gain of +50V/V, R
= 20kΩ for gain of
OUT
LOAD
LOAD
LOAD
+100V/V).
Note 7: +6.25mV = 1/16 of +100mV full-scale voltage.
Note 8: The device will not experience phase reversal when overdriven.
Note 9: All comparator tests are done with V
= +12V.
RS+
Note 10: V
is defined as an externally applied voltage through a resistor to pull up the comparator output.
PULL-UP
Note 11: V is extrapolated from the gain accuracy test.
OS
Typical Operating Characteristics
(V
= +12V, V = +12V, R
= 1MΩ, V
= 0V, V
= 100mV, V
= +5V, R
= 10kΩ, T = +25°C, unless
RS+
CC
LOAD
RESET
SENSE
PULL-UP
PULL-UP
A
otherwise noted.)
TOTAL OUTPUT ERROR
vs. SUPPLY VOLTAGE
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SUPPLY CURRENT
vs. COMMON-MODE VOLTAGE
2.0
1.5
1.0
0.5
0
60
50
40
30
20
10
0
52
51
50
49
48
47
46
45
44
MAX4374/MAX4375
MAX4374/MAX4375
A
= +100V/V
MAX4373
V
A
= +50V/V
V
A
= +20V/V
V
-0.5
-1.0
-1.5
-2.0
MAX4373
= 5mV
V
= 5mV
SENSE
5
V
SENSE
V
= 100mV
SENSE
0
10
15
20
25
30
2
4
6
8
10 12 14 16 18 20 22 24 26 28
SUPPLY VOLTAGE (V)
0
5
10
15
20
25
30
SUPPLY VOLTAGE (V)
COMMON-MODE VOLTAGE (V)
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Maxim Integrated | 4
Low-Cost, Micropower, High-Side
Current-Sense Amplifier +
MAX4373/MAX4374/MAX4375
Comparator + Reference ICs
Typical Operating Characteristics (continued)
(V
= +12V, V = +12V, R
= 1MΩ, V
= 0V, V
= 100mV, V
= +5V, R
= 10kΩ, T = +25°C, unless
RS+
CC
LOAD
RESET
SENSE
PULL-UP
PULL-UP
A
otherwise noted.)
TOTAL OUTPUT ERROR
vs. SUPPLY VOLTAGE
TOTAL OUTPUT ERROR
vs. SENSE VOLTAGE
TOTAL OUTPUT ERROR
vs. SENSE VOLTAGE
5
1.5
1.0
2.0
1.5
1.0
0.5
0
V
= +5.5V
CC
4
A
= +50V/V
3
V
A
= +100V/V
V
0.5
2
A = +100V/V
V
A = +20V/V
V
A
= +100V/V
V
0
1
A
= +20V/V
V
0
-0.5
-1.0
-1.5
-2.0
-2.5
A
= +20V/V
V
-1
-2
-3
-4
-5
A = +50V/V
V
-0.5
-1.0
-1.5
-2.0
A
= +50V/V
V
V
= 6.25mV
SENSE
2
4
6
8
10 12 14 16 18 20 22 24 26 28
SUPPLY VOLTAGE (V)
0
25
50
75
100
125
150
0
25
50
75
100
125
150
V
(mV)
V
(mV)
SENSE
SENSE
TOTAL OUTPUT ERROR
vs. COMMON-MODE VOLTAGE
TOTAL OUTPUT ERROR
vs. SENSE VOLTAGE
12
10
8
3.0
2.5
2.0
1.5
1.0
0.5
0
V
= +28V
CC
A
= +100V/V
V
A
= +100V/V
V
6
A
= +50V/V
V
4
A
= +20V/V
A
= +50V/V
V
V
2
0
A
= +20V/V
V
-2
0
25
50
75
100
125
150
2
4
6
8
10 12 14 16 18 20 22 24 26 28
V
(mV)
COMMON-MODE VOLTAGE (V)
SENSE
SMALL-SIGNAL PULSE RESPONSE
SMALL-SIGNAL PULSE RESPONSE
SMALL-SIGNAL PULSE RESPONSE
(A = +20V/V)
(A = +50V/V)
(A = +100V/V)
V
V
V
MAX4373 toc11
MAX4373 toc09
MAX4373 toc10
30mV
10mV
30mV
30mV
10mV
10mV
600mV
200mV
3V
1V
1.5V
500mV
20μs/div
20μs/div
20μs/div
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Maxim Integrated | 5
Low-Cost, Micropower, High-Side
Current-Sense Amplifier +
MAX4373/MAX4374/MAX4375
Comparator + Reference ICs
Typical Operating Characteristics (continued)
(V
= +12V, V = +12V, R
= 1MΩ, V
= 0V, V
= 100mV, V
= +5V, R = 10kΩ, T = +25°C, unless
PULL-UP A
RS+
CC
LOAD
RESET
SENSE
PULL-UP
otherwise noted.)
LARGE-SIGNAL PULSE RESPONSE
LARGE-SIGNAL PULSE RESPONSE
LARGE-SIGNAL PULSE RESPONSE
(A = +100V/V)
(A = +20V/V)
V
(A = +50V/V)
V
V
MAX4373 toc14
MAX4373 toc13
MAX4373 toc12
95mV
5mV
150mV
150mV
50mV
50mV
9.5V
7.5V
2.5V
3V
1V
500mV
20μs/div
20μs/div
20μs/div
COMMON-MODE REJECTION
vs. FREQUENCY
POWER-SUPPLY REJECTION
vs. FREQUENCY
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
10
100
1k
10k
100k
10
100
1k
10k
100k
FREQUENCY (Hz)
FREQUENCY (Hz)
LARGE-SIGNAL GAIN
vs. FREQUENCY
SMALL-SIGNAL GAIN
vs. FREQUENCY
5
4
3
2
1
0
5
4
V
V
= 100mV (20, 50)
P-P
IN
IN
= 50mV (100)
P-P
3
2
A
= +20V/V
A
V
= +20V/V
V
A
= +50V/V
A
= +50V/V
1
V
V
0
A
= +100V/V
-1
-2
-3
-4
-5
-1
-2
-3
-4
-5
V
A
= +100V/V
V
1k
10k
FREQUENCY (Hz)
100k
1k
10k
100k
1000k
FREQUENCY (Hz)
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Low-Cost, Micropower, High-Side
Current-Sense Amplifier +
MAX4373/MAX4374/MAX4375
Comparator + Reference ICs
Typical Operating Characteristics (continued)
(V
= +12V, V = +12V, R
= 1MΩ, V
= 0V, V
= 100mV, V
= +5V, R = 10kΩ, T = +25°C, unless
PULL-UP A
RS+
CC
LOAD
RESET
SENSE
PULL-UP
otherwise noted.)
POWER-UP DELAY
COMPARATOR POWER-UP DELAY
MAX4373 toc20
MAX4373 toc19
V
CC
= V
PULL-UP
A = +20V/V
V
5V
0
6V
0
V
CC
V
CC
2V
5V
0
OUTPUT
OUTPUT
0
100μs/div
10µs/div
COMPARATOR TRIP POINT vs.
SUPPLY VOLTAGE
COMPARATOR PROPAGATION DELAY
600
599
598
597
596
595
594
593
592
591
590
V
OD
= 5mV
INPUT
125mV/div
OUTPUT
2.5V/div
0
5
10
15
20
25
30
2μs/div
SUPPLY VOLTAGE (V)
COMPARATOR PROPAGATION DELAY
vs. TEMPERATURE
COMPARATOR PROPAGATION DELAY
vs. OVERDRIVE VOLTAGE
7
3.8
3.6
3.4
3.2
3.0
2.8
2.6
2.4
2.2
2
V
= 5mV
OD
6
5
4
3
2
1
0
-50 -30 -10
10
30
50
70
90
0
20 40 60 80 100 120 140 160 180 200
OVERDRIVE VOLTAGE (mV)
TEMPERATURE (°C)
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Maxim Integrated | 7
Low-Cost, Micropower, High-Side
Current-Sense Amplifier +
MAX4373/MAX4374/MAX4375
Comparator + Reference ICs
Typical Operating Characteristics (continued)
(V
= +12V, V = +12V, R
= 1MΩ, V
= 0V, V
= 100mV, V
= +5V, R = 10kΩ, T = +25°C, unless
PULL-UP A
RS+
CC
LOAD
RESET
SENSE
PULL-UP
otherwise noted.)otherwise noted.)
COMPARATOR RESET VOLTAGE
vs. SUPPLY VOLTAGE
COMPARATOR V vs. I
OL
SINK
90
80
70
60
50
40
30
20
10
0
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0
5
10
15
20
25
30
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
(mA)
SUPPLY VOLTAGE (V)
I
SINK
TOTAL OUTPUT ERROR
vs. TEMPERATURE
SUPPLY CURRENT
vs. TEMPERATURE
COMPARATOR AC RESPONSE
MAX4373 toc31
1.0
70
60
50
40
30
20
10
750mV
250mV
MAX4374
MAX4375
0.8
0.6
0.4
0.2
0
INPUT
MAX4373
5V
0
OUTPUT
V
= 5mV
SENSE
0
-60 -40 -20
0
20 40 60 80 100
-60 -40 -20
0
20 40 60 80 100
10μs/div
TEMPERATURE (°C)
TEMPERATURE (°C)
COMPARATOR TRIP POINT
vs. TEMPERATURE
GAIN ACCURACY
vs. TEMPERATURE
605
604
603
602
601
600
599
598
597
596
595
1.0
0.8
0.6
0.4
0.2
0
A
= +20V/V, +50V/V
V
A
= +100V/V
V
-60 -40 -20
0
20 40 60 80 100
-60 -40 -20
0
20 40 60 80 100
TEMPERATURE (°C)
TEMPERATURE (°C)
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Pin Description
PIN
MAX4373
MAX4374/MAX4375
NAME
FUNCTION
µMAX/SO
µMAX
SO
1
1
2
V
CC
Supply Voltage Input
Voltage Output. V
1
2
2
OUT
is proportional to V
(V
- V ).
OUT
SENSE RS+ RS-
Comparator Input 1. Positive input of an internal comparator. The nega-
tive terminal is connected to a 0.6V internal reference.
3
3
4
4
5
CIN1
Comparator Input 2. Terminal of a second internal comparator. The pos-
itive terminal for the MAX4374 and the negative terminal for the
MAX4375. The other terminal is connected to a 0.6V internal reference.
—
CIN2
5
6
7
8
GND
Ground
4
5
Reset Input. Resets the output latch of the comparator at CIN1.
RESET
Open-Drain Comparator Output. Latching output of the comparator con-
trolled by CIN1. Connect RESET to GND to disable the latch.
6
8
7
11
10
COUT1
COUT2
Open-Drain Comparator Output. Output of the second unlatched inter-
nal comparator.
—
7
8
9
13
14
RS-
RS+
N.C.
Load-Side Connection for the External Sense Resistor
Power Connection to the External Sense Resistor
No Connection. Not internally connected.
10
—
—
3, 6, 9, 12
Detailed Description
+ V
R
-
SENSE
V
= 0 TO 28V
IN
The MAX4373 high-side current-sense supervisor fea-
tures a high-side current-sense amplifier, bandgap ref-
erence, and comparator with latching output to monitor
a supply for an overcurrent condition (Figure 1). The
latching output allows the comparator to shut down a
power supply without oscillations. The MAX4374/
MAX4375 offer an additional comparator to allow win-
dow detection of the current.
SENSE
LOAD
RS+
RS-
V
CC
CURRENT-
SENSE
AMPLIFIER
OUT
CIN1
CIN2
V
PULL-UP
(UP TO 5V)
R1
R4
R5
R3
COUT1
+
-
V
PULL-UP
(UP TO 5V)
R2
Current-Sense Amplifier
RESET
COUT2
R6
The internal current-sense amplifier features a 0V to
+28V input common-mode range that is independent of
the supply voltage. With this feature, the device can
monitor the output current of a battery in deep dis-
charge and also high-side current-sensing voltages
+(-)
-(+)
0.6V
BANDGAP
REFERENCE
exceeding V
.
CC
MAX4374
(MAX4375)
The current-sense amplifier is also suitable for low-side
current sensing. However, the total output voltage error
GND
will increase when V
falls below 2V, as shown in
RS+
the Electrical Characteristics and Typical Operating
Characteristics.
Figure 1. Functional Diagram
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Internal Comparator(s)
The MAX4373/MAX4374/MAX4375 contain an open-
drain output comparator for current limiting. The com-
parator’s negative terminal is connected to the internal
600mV reference. The positive terminal is accessible at
CIN1. When RESET is high, the internal latch is active,
and once CIN1 rises above 600mV, the output latches
into the open state. Pulsing RESET low for 1.5µs resets
the latch, and holding RESET low makes the latch
transparent. See RESET at Power-Up section
LOAD
RS+
RS-
2.7V TO 5.5V
COUT1
OUT
V
CC
MAX4373
R
The MAX4374/MAX4375 contain an additional open-
drain comparator. The negative terminal of the
MAX4374’s additional comparator and the positive ter-
minal of the MAX4375’s additional comparator are con-
nected to the internal 600mV reference as shown in
Figure 1. The positive terminal of the MAX4374’s addi-
tional comparator and the negative terminal of the
MAX4375’s additional comparator are accessible at
CIN2.
CIN1
RESET
PUSHBUTTON
C
GND
Applications Information
Figure 2. MAX4373 Overcurrent Protection Circuit
Recommended Component Values
Ideally, the maximum load current will develop the full-
scale sense voltage across the current-sense resistor.
Overcurrent Protection Circuit
The overcurrent protection circuit, shown in Figure 2,
uses the MAX4373 to control an external P-channel
MOSFET. The MOSFET controlled by the MAX4373
opens the current path under overload conditions. The
latched output of the MAX4373’s comparator prevents
the circuit from oscillating, and the pushbutton resets
the current path after an overcurrent condition.
VOUT = VSENSE × AV
Choose the gain version needed to yield the maximum
output voltage required for the application:
where V
is the full-scale sense voltage, 150mV for
SENSE
Window Detection Circuit
gains of +20V/V and +50V/V or 100mV for a gain of
+100V/V. A is the gain of the device. The minimum
Figure 3 shows a simple circuit suitable for window
V
detection. Let I
be the minimum load current
OVER
supply voltage is V
the gain of +100V/V is internally clamped at 12V.
+ 0.25V. Note that the output for
OUT
⎛
⎜
⎞
VREF
RSENSE × AV ⎝
R4 + R5
IUNDER
=
⎟
R5
⎠
V
SENSE(MAX)
RSENSE(MAX)
=
and
ILOAD
⎛
⎜
⎞
VREF
R1 + R2
IOVER
=
⎟
Calculate the maximum value for R
differential voltage across RS+ and RS- does not
exceed the full-scale sense voltage:
so that the
SENSE
RSENSE × AV ⎝ R2
⎠
(I
) required to cause a low state at COUT2, and let
LOAD
Choose the highest value resistance possible to maxi-
I
be the maximum load current required to cause
UNDER
a high state at COUT1:
mize V
and thus minimize total output error.
SENSE
In applications monitoring high current, ensure that
SENSE
where A is the gain of the device and V
V
is the inter-
REF
R
is able to dissipate its own I2R loss. If the resis-
nal reference voltage (0.6V typ).
tor’s power dissipation is exceeded, its value may drift
or it may fail altogether, causing a differential voltage
across the terminals in excess of the absolute maxi-
mum ratings. Use resistors specified for current-sens-
ing applications.
Connect COUT1 and COUT2; the resulting comparator
output will be high when the current is inside the cur-
rent window and low when the current is outside the
window. The window is defined as load currents less
than I
and greater than I
.
OVER
UNDER
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I
RESET at Power-Up
LOAD
+ V
R
-
SENSE
The RESET pin is used to control the latch function of
comparator 1. Holding RESET low (<0.8V) makes the
latch transparent and COUT1 will respond to changes
at CIN1, above and below the internal 600mV reference
threshold voltage. When RESET is high (>2.0V), once
CIN1 rises above 600mV, COUT1 latches into the
open-drain OFF state and remains in this state even if
CIN1 drops below 600mV. Pulsing RESET low for at
least 1.5µs resets the latch.
V
IN
= 0 TO 28V
SENSE
LOAD
RS+
RS-
V
= 2.7V TO 28V
CC
V
CC
OUT
V
PULL-UP
(UP TO 5V)
R1
R2
MAX4375
R3
There is no internal circuitry to control the reset function
CIN2
R4
during power-up. To prevent false latching, RESET
COUT1
must be held low until the V
power has risen above
CC
the 2.7V minimum operating supply voltage. This is
easily accomplished when RESET is driven under µC or
logic gate control. However, if RESET is to be always
CIN1
COUT2
RESET
connected high, add an RC between V , RESET and
CC
GND
R5
GND (see Figure 2). Note that RESET cannot exceed
V
CC
+ 0.3V or +12V, whichever is less.
GND
The following formula can be used to determine the
appropriate RC value.
Figure 3. MAX4375 Window Detector
T
T
RC =
=
ln 2.7V/(2.7V − 0.8V)
0.3514
(
)
Power-Supply Bypassing
It is recommended that V
be bypassed to GND with
CC
where T is the maximum time for V
to reach 2.7V and
CC
at least a 0.1µF ceramic capacitor to isolate the IC from
supply voltage transients. It is possible that plugging
in/out a battery or AC adapter/charger could cause
0.8V is the maximum RESET logic low voltage. For
example, a 470kΩ resistor and 0.22µF capacitor will
keep RESET low during a power-up time of up to 36ms.
A faster power-up time is also safe with the calculated
R and C since the capacitor will have even less time to
charge.
large, fast line transients (>5V/µs) at V . The simplest
CC
solution is to run V
from a better regulated supply
CC
(+5V for example), since V
and RS+ (or RS-) do not
CC
have to be connected together.
For high-speed V transients, another solution is to
CC
add a resistor in series with the V
pin and a 0.1µF
CC
capacitor to create an RC time constant to slow the rise
time of the transient. Since these current-sense ampli-
fiers consume less than 100µA, even a 2.5kΩ resistor
only drops an extra 250mV at V . For most applica-
CC
tions with fast transients, 1kΩ in conjunction with a
0.1µF bypass capacitor works well.
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Pin Configurations
TOP VIEW
+
V
CC
1
2
3
4
5
6
7
14
13
12
11
10
9
RS+
OUT
N.C.
CIN1
CIN2
N.C.
GND
RS-
+
+
V
N.C.
V
CC
1
2
3
4
8
7
6
5
RS+
CC
1
2
3
4
5
10 RS+
MAX4374
MAX4375
COUT1
COUT2
N.C.
OUT
CIN1
CIN2
GND
9
8
7
6
RS-
OUT
CIN1
GND
RS-
MAX4373
MAX4374
MAX4375
COUT1
COUT2
RESET
COUT1
RESET
8
RESET
µMAX/SO
µMAX
SO
Ordering Information (continued)
Chip Information
SUBSTRATE CONNECTED TO GND
PIN-
GAIN
(V/V)
PART
TEMP RANGE
PACKAGE
MAX4374TEUB+ -40°C to +85°C 10 µMAX
MAX4374TESD+ -40°C to +85°C 14 SO
MAX4374FEUB+ -40°C to +85°C 10 µMAX
MAX4374FESD+ -40°C to +85°C 14 SO
MAX4374HEUB+ -40°C to +85°C 10 µMAX
MAX4374HESD+ -40°C to +85°C 14 SO
MAX4375TEUB+ -40°C to +85°C 10 µMAX
MAX4375TESD+ -40°C to +85°C 14 SO
MAX4375FEUB+ -40°C to +85°C 10 µMAX
MAX4375FESD+ -40°C to +85°C 14 SO
MAX4375HEUB+ -40°C to +85°C 10 µMAX
MAX4375HESD+ -40°C to +85°C 14 SO
+20
+20
Package Information
+50
+50
For the latest package outline information and land patterns (foot-
prints), go to www.maximintegrated.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.
+100
+100
+20
+20
OUTLINE
NO.
PACKAGE
TYPE
PACKAGE
CODE
LAND
PATTERN NO.
+50
+50
21-0041
21-0036
21-0061
21-0041
8 SOIC
8 µMAX
10 µMAX
14 SOIC
S8+2
U8+1
90-0096
90-0092
90-0330
90-0096
+100
+100
U10+2
S14+1
+Denotes a lead(Pb)-free/RoHS-compliant package.
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Revision History
REVISION REVISION
PAGES
CHANGED
DESCRIPTION
NUMBER
DATE
Clarified 0V to 2V is not a high-accuracy range for the device, added lead-free
options and soldering temperature
3
6/10
1, 2, 12
4
5
1/11
5/15
Clarified V
conditions in Electrical Characteristics table
2
1
RS+
Added the Benefits and Features section
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-.29-4.42, or visit Maxim Integrated’s website at wwwꢀmaximintegratedꢀcomꢀ
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent
licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and
max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
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