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19-1630; Rev 0; 3/00
Low-Cost, Micropower, High-Side Current-Sense Amplifier + Comparator + Reference ICs
General Description
The MAX4373/MAX4374/MAX4375 low-cost, micropower, high-side current-sense supervisors contain a highside 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. 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-detection 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 integration, resulting in a simple and compact currentsense solution. The MAX4373/MAX4374/MAX4375 operate from a single +2.7V to +28V supply and consume 50A. They are specified for the extended operating temperature range (-40C to +85C) and are available in 8-pin and 10-pin MAX packages.
Features
o Current-Sense Amplifier plus Internal Comparator and Bandgap Reference o 50A Supply Current o Single +2.7V to +28V Operating Supply o 0.66% Full-Scale Accuracy o Internal Bandgap Reference o Latching Comparator Output o Three Gain Versions Available (+20V/V, +50V/V, +100V/V) o Wide 0 to +28V Common-Mode Range, Independent of Supply Voltage
MAX4373/MAX4374/MAX4375
Ordering Information
PART MAX4373TEUA MAX4373TESA MAX4373FEUA MAX4373FESA MAX4373HEUA MAX4373HESA TEMP. RANGE -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C PINPACKAGE 8 MAX 8 SO 8 MAX 8 SO 8 MAX 8 SO GAIN (V/V) +20 +20 +50 +50 +100 +100
Ordering Information continues at end of data sheet.
________________________Applications
Notebook Computers Portable/Battery-Powered Systems Smart Battery Packs/Chargers Cell Phones Power-Management Systems General-System/Board-Level Current Monitoring Precision Current Sources
VPULL-UP = 5V R3 VCC = 2.7V TO 28V C1 0.1F VIN = 0 TO 28V
Typical Operating Circuit
+ VSENSE RSENSE RS+ VCC RSLOAD/ BATTERY ILOAD
MAX4373
OUT R1 CIN R2 GND
COUT RESET
Pin Configurations appear at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
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Low-Cost, Micropower, High-Side Current-Sense Amplifier + Comparator + Reference ICs MAX4373/MAX4374/MAX4375
ABSOLUTE MAXIMUM RATINGS
VCC, RS+, RS- to GND ...........................................-0.3V to +30V OUT to GND ................................................-0.3V to the lesser of (VCC + 0.3V) or +15V CIN1, CIN2, RESET to GND ........................-0.3V to the lesser of (VCC + 0.3V) or +12V Differential Input Voltage (VRS+ - VRS-) ..............................0.3V COUT1, COUT2 to GND........................................-0.3V to +6.0V Current into Any Pin..........................................................10mA Continuous Power Dissipation (TA = +70C) 8-Pin MAX (derate 4.1mW/C above +70C) .............330mW 8-Pin SO (derate 5.9mW/C above +70C)..................471mW 10-Pin MAX (derate 5.6mW/C above +70C) ...........444mW 14-Pin SO (derate 8.3mW/C above +70C)................667mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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
(VCC = +2.7V to +28V, VRS+ = 0 to +28V, VSENSE = 0, V RESET = 0, RLOAD= 1M, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 1) PARAMETER Operating Voltage Range (Note 2) Common-Mode Input Range (Note 3) Common-Mode Rejection Supply Current Leakage Current SYMBOL VCC VCMR CMR ICC VRS+ > 2V VRS+ > 2V, VSENSE = 5mV VRS+ > 2V VRS+ 2V VRS+ > 2V VRS+ 2V Gain = +20V/V, +50V/V Gain = +100V/V VSENSE = 100mV, VCC = 12V, VRS+ = 12V, TA = +25C VCC = 12V, VRS+ = 12V, TA = TMIN to TMAX Total OUT Voltage Error (Note 5) VSENSE = 100mV (Note 6) VCC = 28V, VRS+ = 28V, TA = TMIN to TMAX VCC = 12V, VRS+ = 0.1V VSENSE = 6.25mV, VCC = 12V, VRS+ = 12V (Note 7) OUT Voltage Low OUT Voltage High VOUT VCC VOH VCC = 2.7V IOUT = 10A IOUT = 100A 0.55 5.0 5.0 2.5 8.5 65 0.25 mV V 0 -25 0 -50 150 100 170 120 0.66 5.5 7.5 7.5 % CONDITIONS MIN 2.7 0 85 50 0.015 100 0.5 2.5 2.0 4 4 mV % A TYP MAX 28 28 UNITS V V dB A A
IRS+, IRS- VCC = 0 IRS+
Input Bias Current IRSFull-Scale Sense Voltage (Note 4) Full-Scale Accuracy (Note 5) VSENSE
VCC = 2.7V, IOUT = -500A
2
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Low-Cost, Micropower, High-Side Current-Sense Amplifier + Comparator + Reference ICs
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +2.7V to +28V, VRS+ = 0 to +28V, VSENSE = 0, V RESET = 0, RLOAD= 1M, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 1) PARAMETER SYMBOL CONDITIONS VSENSE = 100mV, Gain = +20V/V -3dB Bandwidth BW VRS+ = 12V, VCC = 12V, CLOAD = 10pF VSENSE = 100mV, Gain = +50V/V VSENSE = 100mV, Gain = +100V/V VSENSE = 6.25mV MAX437_T Gain AV MAX437_F MAX437_H VSENSE = TA = +25C 20mV to 150mV; VCC = 12V; VRS+ = 12V; TA = -40C to +85C Gain = 20, 50 VSENSE = TA = +25C 20mV to 100mV, VCC = 12V, VRS+ = 12V, TA = -40C to +85C Gain = 100 Gain = +20V/V, VCC = 12V, VRS+ = 12V, CLOAD = 10pF ROUT PSR VSENSE = 100mV VOUT = 2V, VRS+ > 2V VSENSE = 100mV, CLOAD = 10pF, VCC = 12V, VRS+ = 12V VCC = 12V, VRS+ = 12V, CLOAD = 10pF 72 VSENSE = 6.25mV to 100mV VSENSE = 100mV to 6.25mV MIN TYP 200 120 110 50 +20 +50 +100 0.64 5.2 7.2 % 0.62 5.0 7.2 20 s 20 1000 1.5 87 0.5 0.1 pF dB ms ms V/V MAX UNITS
MAX4373/MAX4374/MAX4375
kHz
Gain Accuracy
AV
OUT Settling Time to 1% of Final Value Capacitive Load Stability OUT Output Resistance Power-Supply Rejection Power-Up Time to 1% of Final Value Saturation Recovery Time (Note 8) COMPARATOR (Note 9) Comparator Threshold Comparator Hysteresis Input Bias Current Propagation Delay Output Low Voltage VOL IB
No sustained oscillations
580
600 -9 2.2
618 15
mV mV nA s
CL = 10pF, RL = 10k pull-up to 5V, 5mV of overdrive ISINK = 1mA
4 0.6
V
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3
Low-Cost, Micropower, High-Side Current-Sense Amplifier + Comparator + Reference ICs MAX4373/MAX4374/MAX4375
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +2.7V to +28V, VRS+ = 0 to +28V, VSENSE = 0, V RESET = 0, RLOAD= 1M, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 1) PARAMETER Output High Leakage Current RESET Input High Voltage RESET Input Low Voltage Logic Input Current Minimum RESET Pulse Width RESET Propagation Delay Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: Note 7: Note 8: Note 9: Note 10: VIH VIL IIL, IIH tRPW tRPD VIL = 0, VIH = 5.5V, VCC = 28V -0.5 1.5 3 SYMBOL CONDITIONS VCC = 28V, VPULL-UP = 5V (Note 10) 2.0 0.8 0.5 INTYP MAX 1 UNITS A V V A s s
All devices are 100% production tested at TA = +25C. All temperature limits are guaranteed by design. Guaranteed by PSR test. Guaranteed by OUT Voltage Error test. Guaranteed by Gain Accuracy test. Output voltage is internally clamped not to exceed 12V. Total OUT Voltage Error and Full-Scale Accuracy are the sum of gain and offset voltage errors. Measured at IOUT = -500A (RLOAD = 4k for gain of +20V/V, RLOAD = 10k for gain of +50V/V, RLOAD = 20k for gain of +100V/V). +6.25mV = 1/16 of +100mV full-scale voltage. The device will not experience phase reversal when overdriven. All comparator tests are done with VRS+ = +12V. VPULL-UP is defined as an externally applied voltage through a resistor to pull up the comparator output.
Typical Operating Characteristics
(VRS+ = +12V, VCC = +12V, R LOAD = 1M, V RESET = 0, VSENSE = 100mV, VPULL-UP = +5V, RPULL-UP = 10k, TA = +25C, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX4373 toc01
SUPPLY CURRENT vs. COMMON-MODE VOLTAGE
MAX4373 toc02
TOTAL OUTPUT ERROR vs. SUPPLY VOLTAGE
1.5 1.0 OUTPUT ERROR (%) 0.5 0 AV = +20V/V -0.5 -1.0 -1.5 AV = +50V/V AV = +100V/V
MAX4373 toc03
60 MAX4374/MAX4375 50 SUPPLY CURRENT (A) 40 30 20 10 VSENSE = 5mV 0 0 5 10 15 20 25 MAX4373
52 51 SUPPLY CURRENT (A) 50 49 48 47 MAX4373 46 45 VSENSE = 5mV 44 MAX4374/MAX4375
2.0
-2.0 0 5 10 15 20 25 30 2 4 6 8 10 12 14 16 18 20 22 24 26 28 SUPPLY VOLTAGE (V) COMMON-MODE VOLTAGE (V)
30
SUPPLY VOLTAGE (V)
4
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Low-Cost, Micropower, High-Side Current-Sense Amplifier + Comparator + Reference ICs
Typical Operating Characteristics (continued)
(VRS+ = +12V, VCC = +12V, R LOAD = 1M, V RESET = 0, VSENSE = 100mV, VPULL-UP = +5V, RPULL-UP = 10k, TA = +25C, unless otherwise noted.)
TOTAL OUTPUT ERROR vs. SUPPLY VOLTAGE
MAX4373 toc04
MAX4373/MAX4374/MAX4375
TOTAL OUTPUT ERROR vs. SENSE VOLTAGE
VCC = +5.5V 1.0 OUTPUT ERROR (%) 0.5 AV = +100V/V 0 -0.5 -1.0 -1.5 -2.0 -2.5 AV = +50V/V AV = +20V/V
MAX4373 toc05
TOTAL OUTPUT ERROR vs. SENSE VOLTAGE
1.5 OUTPUT ERROR (%) 1.0 0.5 0 -0.5 -1.0 -1.5 -2.0 0 25 50 75 VSENSE (mV) 100 125 150 AV = +50V/V AV = +100V/V AV = +20V/V
MAX4373 toc06
5 4 3 OUTPUT ERROR (%) 2 1 0 -1 -2 -3 -4 -5 AV = +20V/V AV = +100V/V AV = +50V/V
1.5
2.0
2 4 6 8 10 12 14 16 18 20 22 24 26 28 SUPPLY VOLTAGE (V)
0
25
50
75 VSENSE (mV)
100
125
150
TOTAL OUTPUT ERROR vs. SENSE VOLTAGE
VCC = +28V
MAX4373 toc07
TOTAL OUTPUT ERROR vs. COMMON-MODE VOLTAGE
10 OUTPUT ERROR (%) 8 6 4 2 0 -2 AV = +20V/V 2 4 6 8 10 12 14 16 18 20 22 24 26 28 COMMON-MODE VOLTAGE (V) AV = +50V/V AV = +100V/V
MAX4373 toc08
3.0 2.5 OUTPUT ERROR (%) AV = +100V/V 2.0 1.5 1.0 0.5 0 0 25 50 75 VSENSE (mV) 100 AV = +20V/V
12
AV = +50V/V
125
150
SMALL-SIGNAL PULSE RESPONSE (AV = +20V/V)
MAX4373 toc09
SMALL-SIGNAL PULSE RESPONSE (AV = +50V/V)
MAX4373 toc10
SMALL-SIGNAL PULSE RESPONSE (AV = +100V/V)
MAX4373 toc11
INPUT
INPUT
INPUT
30mV
30mV
30mV 10mV
10mV
10mV
OUTPUT
OUTPUT
OUTPUT
600mV
1.5V
3V
200mV
500mV
1V
20s/div
20s/div
20s/div
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Low-Cost, Micropower, High-Side Current-Sense Amplifier + Comparator + Reference ICs MAX4373/MAX4374/MAX4375
Typical Operating Characteristics (continued)
(VRS+ = +12V, VCC = +12V, R LOAD = 1M, V RESET = 0, VSENSE = 100mV, VPULL-UP = +5V, RPULL-UP = 10k, TA = +25C, unless otherwise noted.)
LARGE-SIGNAL PULSE RESPONSE (AV = +20V/V)
MAX4373 toc12
LARGE-SIGNAL PULSE RESPONSE (AV = +50V/V)
MAX4373 toc13
LARGE-SIGNAL PULSE RESPONSE (AV = +100V/V)
MAX4373 toc14
INPUT
INPUT
150mV
150mV INPUT
95mV
50mV
50mV
5mV
OUTPUT
OUTPUT
1V
2.5V
OUTPUT
3V
7.5V
9.5V
500mV
20s/div
20s/div
20s/div
COMMON-MODE REJECTION vs. FREQUENCY
MAX4373 toc15
POWER-SUPPLY REJECTION vs. FREQUENCY
-10 -20 -30 PSR (dB) -40 -50 -60 -70 -80 -90 -100
MAX4373 toc16
0 -10 -20 -30 CMR (dB) -40 -50 -60 -70 -80 -90 -100 10 100 1k FREQUENCY (Hz) 10k
0
100k
10
100
1k FREQUENCY (Hz)
10k
100k
SMALL-SIGNAL GAIN vs. FREQUENCY
MAX4373 toc17
LARGE-SIGNAL GAIN vs. FREQUENCY
4 3 2 1 GAIN (dB) 0 -1 -2 -3 -4 -5 AV = +100V/V VIN = 100mVp-p (20, 50) VIN = 50mVp-p (100)
MAX4373 toc18
5 4 3 2 GAIN (dB) 1 0 -1 -2 -3 -4 -5 1k 10k 100k AV = +100V/V AV = +50V/V AV = +20V/V
5
AV = +20V/V
AV = +50V/V
1000k
1k
10k FREQUENCY (Hz)
100k
FREQUENCY (Hz)
6
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Low-Cost, Micropower, High-Side Current-Sense Amplifier + Comparator + Reference ICs
Typical Operating Characteristics (continued)
(VRS+ = +12V, VCC = +12V, R LOAD = 1M, V RESET = 0, VSENSE = 100mV, VPULL-UP = +5V, RPULL-UP = 10k, TA = +25C, unless otherwise noted.)
MAX4373/MAX4374/MAX4375
POWER-UP DELAY
MAX4373 toc19
COMPARATOR POWER-UP DELAY
MAX4373 toc20
AV = +20V/V 6V VCC 0 VCC
VCC = VPULL-UP 5V
0
2V OUTPUT OUTPUT 0 100s/div 10s/div
5V
0
COMPARATOR TRIP POINT vs. SUPPLY VOLTAGE
MAX4373 toc21
COMPARATOR PROPAGATION DELAY
VOD = 5mV INPUT 125mV/div
MAX4373 toc22
600 599 598 TRIP POINT (mV) 597 596 595 594 593 592 591 590 0 5 10 15 20 25
OUTPUT 2.5V/div
30
2s/div
SUPPLY VOLTAGE (V)
COMPARATOR PROPAGATION DELAY vs. OVERDRIVE VOLTAGE
MAX4373 toc24
COMPARATOR PROPAGATION DELAY vs. TEMPERATURE
VOD = 5mV 6 PROPAGATION DELAY (s) 5 4 3 2 1 0
MAX4373 toc26
3.8 3.6 PROGAGATION DELAY (s) 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2 0
7
20 40 60 80 100 120 140 160 180 200 OVERDRIVE VOLTAGE (mV)
-50
-30
-10
10
30
50
70
90
TEMPERATURE (C)
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Low-Cost, Micropower, High-Side Current-Sense Amplifier + Comparator + Reference ICs MAX4373/MAX4374/MAX4375
Typical Operating Characteristics (continued)
(VRS+ = +12V, VCC = +12V, R LOAD = 1M, V RESET = 0, VSENSE = 100mV, VPULL-UP = +5V, RPULL-UP = 10k, TA = +25C, unless otherwise noted.)
COMPARATOR RESET VOLTAGE vs. SUPPLY VOLTAGE
MAX4373 toc27
COMPARATOR VOL vs. ISINK
80 70 60 VOL (mV) 50 40 30 20
MAX4373 toc28
2.0 1.8 RESET VOLTAGE (V) 1.6 1.4 1.2 1.0 0.8 0 5 10 15 20 25
90
10 0 30 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 SUPPLY VOLTAGE (V) ISINK (mA)
COMPARATOR AC RESPONSE
MAX4373 toc31
SUPPLY CURRENT vs. TEMPERATURE
750mV
MAX4373 toc32
TOTAL OUTPUT ERROR vs. TEMPERATURE
MAX4373 toc33
70 60 SUPPLY CURRENT (A) 50 40 30 20 10 VSENSE = 5mV 0 MAX4373 MAX4374 MAX4375
1.0
250mV
TOTAL OUTPUT ERROR (%)
INPUT
0.8
0.6
5V OUTPUT 0
0.4
0.2
0 -60 -40 -20 0 20 40 60 80 100 -60 -40 -20 0 20 40 60 80 100 TEMPERATURE (C) TEMPERATURE (C)
10s/div
GAIN ACCURACY vs. TEMPERATURE
MAX4373 toc34
COMPARATOR TRIP POINT vs. TEMPERATURE
604 COMPARATOR TRIP POINT (mV) 603 602 601 600 599 598 597 596
MAX4373 toc35
1.0
605
0.8 GAIN ACCURACY (%) AV = +20V/V, +50V/V 0.6 AV = +100V/V
0.4
0.2
0 -60 -40 -20 0 20 40 60 80 100 TEMPERATURE (C)
595 -60 -40 -20 0 20 40 60 80 100 TEMPERATURE (C)
8
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Low-Cost, Micropower, High-Side Current-Sense Amplifier + Comparator + Reference ICs
Pin Description
PIN MAX4373 MAX/SO MAX4374/MAX4375 MAX 1 2 3 SO NAME FUNCTION FUNCTION VCC OUT CIN1 Supply Voltage Input Voltage Output. VOUT is proportional to VSENSE (VRS+ - VRS-). Comparator Input 1. Positive input of an internal comparator. The negative terminal is connected to a 0.6V internal reference. Comparator Input 2. Terminal of a second internal comparator. The positive terminal for the MAX4374 and the negative terminal for the MAX4375. The other terminal is connected to a 0.6V internal reference. Ground Reset Input. Resets the output latch of the comparator at CIN1. Comparator Output. Latching output of the comparator controlled by CIN1. Connect RESET to GND to disable the latch. Comparator Output. Output of the second unlatched internal comparator. Load-Side Connection for the External Sense Resistor Power Connection to the External Sense Resistor No Connection. Not internally connected.
MAX4373/MAX4374/MAX4375
1
2 3
1
2 4
--
4 5 6 8 7 9 10 --
5 7 8 11 10 13 14 3, 6, 9, 12
CIN2 GND RESET COUT1 COUT2 RSRS+ N.C.
4
5 6 -- 7 8 --
VIN = 0 TO 28V RS+ VCC
+ VSENSE RSENSE RSLOAD
Detailed Description
The MAX4373 high-side current-sense supervisor features a high-side current-sense amplifier, bandgap reference, 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 window detection of the current.
VPULL-UP = 5V R3 VPULL-UP = 5V R6 COUT1 RESET COUT2
CURRENTSENSE AMPLIFIER
+ -
OUT R1 CIN1 R2 R4
Current-Sense Amplifier
R5
+(-) -(+)
CIN2
0.6V BANDGAP REFERENCE
MAX4374/MAX4375
GND
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 discharge and also high-side current-sensing voltages exceeding VCC. The current-sense amplifier is also suitable for low-side current sensing. However, the total output voltage error will increase when VRS+ falls below 2V, as shown in
Figure 1. Functional Diagram _______________________________________________________________________________________ 9
Low-Cost, Micropower, High-Side Current-Sense Amplifier + Comparator + Reference ICs MAX4373/MAX4374/MAX4375
the Electrical Characteristics and Typical Operating Characteristics.
Internal Comparator(s)
The MAX4373/MAX4374/MAX4375 contain a latching output comparator. The negative terminal of the comparator is internally connected to the internal reference. The positive terminal is accessible at CIN1. When RESET is high, the comparator output latches high once the comparator threshold is exceeded. When RESET is low, the latch is transparent. The MAX4374 and MAX4375 each contain an additional comparator for use in window detection. The negative terminal of the MAX4374 and the positive terminal of the MAX4375 are internally connected to the internal reference. The positive terminal of the MAX4374 and the negative terminal of the MAX4375 are accessible at CIN2.
RS+ 2.7V TO 5.5V COUT1 VCC OUT RS-
LOAD
MAX4373
CIN1 RESET PUSHBUTTON
GND
___________Applications Information
Recommended Component Values
Ideally, the maximum load current will develop the fullscale sense voltage across the current-sense resistor. Choose the gain version needed to yield the maximum output voltage required for the application: VOUT = VSENSE x AV where VSENSE is the full-scale sense voltage, 150mV for gains of +20V/V and +50V/V or 100mV for a gain of +100V/V. AV is the gain of the device. The minimum supply voltage is VOUT + 0.25V. Note that the output for the gain of +100V/V is internally clamped at 12V. Calculate the maximum value for RSENSE so that the differential voltage across RS+ and RS- does not exceed the full-scale sense voltage: RSENSE(MAX) = VSENSE(MAX) ILOAD
Figure 2. MAX4373 Overcurrent Protection Circuit
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.
Window Detection Circuit
Figure 3 shows a simple circuit suitable for window detection. Let I OVER be the minimum load current (ILOAD) required to cause a low state at COUT2, and let IUNDER be the maximum load current required to cause a high state at COUT1: IUNDER = and IOVER = R1 + R2 VREF RSENSE x AV R2 R4 + R5 VREF RSENSE x AV R5
Choose the highest value resistance possible to maximize VSENSE and thus minimize total output error. In applications monitoring high current, ensure that RSENSE is able to dissipate its own I2R loss. If the resistor'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 maximum ratings. Use resistors specified for current-sensing applications.
where AV is the gain of the device and VREF is the internal reference voltage (0.6V typ). Connect COUT1 and COUT2; the resulting comparator output will be high when the current is inside the current window and low when the current is outside the window. The window is defined as load currents less than IOVER and greater than IUNDER.
10
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Low-Cost, Micropower, High-Side Current-Sense Amplifier + Comparator + Reference ICs
+ VSENSE VIN = 0 TO 28V RSENSE LOAD RS+ VCC = 2.7V TO 28V VCC OUT VPULL-UP = 5V R3 COUT1 R1 RSILOAD
Ordering Information (continued)
PART MAX4374TEUB MAX4374TESD MAX4374FEUB MAX4374FESD MAX4374HEUB MAX4374HESD MAX4375TEUB MAX4375TESD MAX4375FEUB MAX4375FESD MAX4375HEUB MAX4375HESD TEMP. RANGE -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C PINPACKAGE 10 MAX 14 SO 10 MAX 14 SO 10 MAX 14 SO 10 MAX 14 SO 10 MAX 14 SO 10 MAX 14 SO GAIN (V/V) +20 +20 +50 +50 +100 +100 +20 +20 +50 +50 +100 +100
MAX4373/MAX4374/MAX4375
MAX4375
CIN2 R2 COUT2 CIN1 R5 GND R4
VCC
RESET
___________________Chip Information
TRANSISTOR COUNT: 390 SUBSTRATE CONNECTED TO GND
Figure 3. MAX4375 Window Detector
Pin Configurations
TOP VIEW
VCC 1 OUT 2 VCC 1 OUT 2 CIN1 3 8 RS+ RSCOUT1 RESET VCC 1 OUT 2 CIN1 3 CIN2 4 GND 5 10 RS+ N.C. 3 CIN1 4 CIN2 5 N.C. 6 GND 7 14 RS+ 13 RS12 N.C.
MAX4373
7 6 5
MAX4374 MAX4375
9 8 7 6
RSCOUT1 COUT2 RESET
MAX4374 MAX4375
11 COUT1 10 COUT2 9 8 N.C. RESET
GND 4
MAX/SO
MAX
SO
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11
Low-Cost, Micropower, High-Side Current-Sense Amplifier + Comparator + Reference ICs MAX4373/MAX4374/MAX4375
Package Information
8LUMAXD.EPS
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.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
10LUMAX.EPS

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