MAX4377FAUA-T中文资料
MAX4376/MAX4377/MAX4378
Single/Dual/Quad, High-Side Current-Sense
Amplifiers with Internal Gain
________________________________________________________________Maxim Integrated Products
1
19-1781; Rev 3; 5/04
General Description
The MAX4376/MAX4377/MAX4378 single, dual, and quad precision high-side current-sense amplifiers are available in space-saving packages. They feature buffered voltage outputs that eliminate the need for gain-setting resistors and are ideal for today’s notebook computers, cell phones, and other systems where cur-rent monitoring is critical. These precision devices are offered in three fixed-gain versions of 20, 50, and 100:
GAIN SUFFIX 20T 50F 100 H
For example, MAX4376TAUK is a single high-side amplifier with a gain of 20.
High-side current monitoring is especially useful in bat-tery-powered systems since it does not interfere with the ground path of the battery charger. The input com-mon-mode range of 0 to +28V is independent of the supply voltage and ensures that the current-sense feedback remains viable even when connected to a battery pack in deep discharge.
The full-scale current reading can be set by choosing the appropriate voltage gain and external-sense resis-tor. This capability offers a high level of integration and flexibility, resulting in a simple and compact current-sense solution.
The MAX4376/MAX4377/MAX4378 operate over a sup-ply voltage range of +3V to +28V, draw 1mA of supply current per amplifier, and operate over the full automo-tive temperature range of -40°C to +125
°C. These devices have a wide bandwidth of 2MHz, making them suitable for use inside battery-charger control loops.The buffered outputs drive up to 2mA of output current into a ground-referenced load.
The MAX4376 is available in a tiny 5-pin SOT23 pack-age. The MAX4377/MAX4378 are available in space-saving 8-pin μMAX and 14-pin TSSOP packages,respectively.
Applications
Features
o Low-Cost, Single/Dual/Quad, High-Side Current-Sense Amplifiers
o ±0.5% Typical Full-Scale Accuracy o +3V to +28V Supply Operation
o
Adjustable Current-Sense Capability with External Sense Resistor
o Buffered Output Voltage with 2mA Drive o 1mA (typ) Supply Current
o 2.0MHz Bandwidth (Gain = +20V/V)
o Automotive Temperature Range (-40°C to +125°C)o Full 0 to 28V Common-Mode Range, Independent of Supply Voltage
o Three Gain Versions Available
+20V/V (MAX437_T)+50V/V (MAX437_F)+100V/V (MAX437_H)
o Available in Space-Saving 5-Pin SOT23 (Single), 8-Pin μMAX (Dual), and 14-Pin TSSOP (Quad)
Ordering Information continued at end of data sheet.
Ordering Information
Notebook Computers Current-Limited Power Supplies
Fuel Gauges in PC
General-System/Board-Level Current Monitoring Battery Chargers
Portable/Battery-Powered Systems Cell Phones
Smart Battery Packages Automotive Current Detect Power Management Systems
PA Bias Control
Pin Configurations
For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at https://www.wendangku.net/doc/4e16063228.html,.
M A X 4376/M A X 4377/M A X 4378
Single/Dual/Quad, High-Side Current-Sense Amplifiers with Internal Gain
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V RS+= 0 to 28V, V SENSE = (V RS+- V RS-) = 0V, V CC = +3.0V to +28V, R L = ∞, T A = T MIN to T MAX,unless otherwise noted. Typical values are at T A = 25°C.) (Note 1)
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.
V CC , RS+, RS- to GND...........................................-0.3V to +30V OUT to GND...............................................-0.3V to (V CC + 0.3V) Differential Input Voltage (V RS+- V RS- ).................................±8V Output Short Circuit to V CC ........................................Continuous Output Short Circuit to GND.....................................................1s Current into Any Pin..........................................................±20mA Continuous Power Dissipation (T A = +70°C)
5-Pin SOT23 (derate 7.1mW/°C above +70°C)............571mW 8-Pin μMAX (derate 4.5mW/°C above +70°C).............362mW 8-Pin SO (derate 5.88mW/°C above +70°C)................471mW
14-Pin SO (derate 8.33mW/°C above +70°C)..............667mW 14-Pin TSSOP (derate 9.1mW/°C above +70°C).........727mW Operating Temperature Range .........................-40°C to +125°C Junction Temperature......................................................+150°C Storage Temperature Range.............................-65°C to +150°C Lead Temperature (soldering, 10s).................................+300°C
MAX4376/MAX4377/MAX4378
Single/Dual/Quad, High-Side Current-Sense
Amplifiers with Internal Gain
_______________________________________________________________________________________3
ELECTRICAL CHARACTERISTICS (continued)
(V RS+= 0 to 28V, V SENSE = (V RS+- V RS-) = 0V, V CC = +3.0V to +28V, R L = ∞, T A = T MIN to T MAX,unless otherwise noted. Typical values are at T A = 25°C.) (Note 1)
Note 4:V SENSE such that V OUT is in saturation.
M A X 4376/M A X 4377/M A X 4378
Single/Dual/Quad, High-Side Current-Sense Amplifiers with Internal Gain 4_______________________________________________________________________________________
0.50
0.650.600.550.700.750.800.850.900.951.000
10
5
15
20
25
30
SUPPLY CURRENT (PER AMPLIFIER)
vs. SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
S U P P L Y C U R R E N T (m A )
0.40.20.80.61.21.01.4-50
025-255075100125SUPPLY CURRENT (PER AMPLIFIER)
vs. TEMPERATURE
TEMPERATURE (°C)S U P P L Y C U R R E N T (m A )
-1.0
-0.8-0.6-0.4-0.20.00.20.40.60.81.01.2
0510********
TOTAL OUTPUT ERROR
vs. SUPPLY VOLTAGE (V SENSE
= 100mV)
SUPPLY VOLTAGE (V)
T O T A L O U T P U T E R R O R (%)
-1-20123456TOTAL OUTPUT ERROR
vs. SUPPLY VOLTAGE (V SENSE = 6.25mV)
T O T A L O U T P U T E R R O R (%)
-4-30
10
5
15
20
25
30
SUPPLY VOLTAGE (V)
-1.0
-0.4-0.6-0.8-0.200.20.40.60.81.0
010*********
TOTAL OUTPUT ERROR vs. COMMON-MODE VOLTAGE
COMMON-MODE VOLTAGE (V)
T O T A L O U T P U T E R R O R (%)
-2.0
-1.0-1.50-0.51.51.00.52.0GAIN ACCURACY vs. TEMPERATURE
TEMPERATURE (°C)G A I N A C C U R A C Y (%)
-50
-25
25
50
75
100
125Typical Operating Characteristics
(V CC = V RS+ = 12V, V SENSE = 100mV, T A = +25°C.)
-1.0
-0.6-0.8-0.2-0.40.200.40.80.61.0
-50025-255075100125150
TOTAL OUTPUT ERROR vs. TEMPERATURE
TEMPERATURE (°C)
T O T A L O U T P U T E R R O R (%)
MAX4376/MAX4377/MAX4378
Single/Dual/Quad, High-Side Current-Sense
Amplifiers with Internal Gain
_______________________________________________________________________________________5
Typical Operating Characteristics (continued)
(V CC = V RS+ = 12V, V SENSE = 100mV, T A = +25°C.)
2μs/div
MAX4376F
SMALL-SIGNAL TRANSIENT RESPONSE
(V SENSE = 95mV TO 100mV)
IN 5mV/div
OUT 100mV/div
95mV
100mV 5V
4.75V
C L = 15pF R L = 2.5k ?
2μs/div
MAX4376H
SMALL-SIGNAL TRANSIENT RESPONSE
(V SENSE = 95mV to 100mV)
IN 5mV/div
OUT 200mV/div
95mV
100mV 10V
9.5V
C L = 15pF R L = 5k ?
2μs/div MAX4376T
LARGE-SIGNAL TRANSIENT RESPONSE
(V SENSE = 6mV to 100mV)
IN 45mV/div
OUT 500mV/div
6mV 100mV 2V
0.120V
C L = 15pF R L = 1k ?
-2
0-121435TOTAL OUTPUT ERROR
vs. FULL-SCALE SENSE VOLTAGE
V SENSE (mV)
T O T A L O U T P U T E R R O R (%)
50
100150
200
2μs/div
MAX4376T
SMALL-SIGNAL TRANSIENT RESPONSE
(V SENSE = 95mV TO 100mV)
IN 5mV/div
OUT 50mV/div
95mV
100mV 2.0V
1.9V
C L = 15pF R L =1k ?
2μs/div
MAX4376F
LARGE-SIGNAL TRANSIENT RESPONSE
(V SENSE = 6mV to 100mV)
IN 45mV/div
OUT 2V/div
6mV
100mV 5V
0.3V
C L = 15pF R L = 2.5k ?
M A X 4376/M A X 4377/M A X 4378
Single/Dual/Quad, High-Side Current-Sense Amplifiers with Internal Gain 6
_______________________________________________________________________________________
2μs/div
MAX4376H
LARGE-SIGNAL TRANSIENT RESPONSE
(V SENSE = 6mV to 100mV)
IN 45mV/div
OUT 3V/div
6mV 100mV
10V
0.6V
1.E+04
1.E+07
1.E+061.E+05SMALL-SIGNAL GAIN vs. FREQUENCY
15
5
352545
201040
30
FREQUENCY (Hz)
G A I N (d B )
TIME (500ns)
OVERDRIVE RESPONSE
AV = +20V/V
IN
200mV/div
OUT 2V/div
350mV
750mV
V OH
7V
MAX4376/7/8 toc16
0100
50200150350300
250400
OUTPUT LOW vs. TEMPERATURE
TEMPERATURE (°C)
O U T P U T L O W (m V )
-50
-25
25
50
75
100
125
Typical Operating Characteristics (continued)
(V CC = V RS+ = 12V, V SENSE = 100mV, T A = +25°C.)
MAX4376/MAX4377/MAX4378
Single/Dual/Quad, High-Side Current-Sense
Amplifiers with Internal Gain
_______________________________________________________________________________________7
Detailed Description
The MAX4376/MAX4377/MAX4378 high-side current-sense amplifiers feature a 0 to +28V input common-mode range that is independent of supply voltage. This feature allows the monitoring of current out of a battery in deep discharge and also enables high-side current sensing at voltages greater than the supply voltage (V CC ).
The MAX4376/MAX4377/MAX4378 operate as follows:current from the source flows through R SENSE to the load (Figure 1). Since the internal sense amplifier ’s inverting input has high impedance, negligible current flows through RG2 (neglecting the input bias current).Therefore, the sense amplifier ’s inverting-input voltage equals V SOURCE - (I LOAD )(R SENSE ).
The amplifier ’s open-loop gain forces its noninverting input to the same voltage as the inverting input.Therefore, the drop across RG1 equals (I LOAD )(R SENSE ). Since I RG1flows through RG1, I RG1=(I LOAD )(R SENSE )/RG1. The internal current mirror multi-plies I RG1by a current gain factor, β, to give I RGD = βx I RG1. Solving I RGD = βx (I LOAD )(R SENSE )/RG1.Therefore:
V OUT = βx (RGD/RG1)(R SENSE x I LOAD ) x amp gain where amp gain is 2, 5, or 10.
The part ’s gain equals (βx RGD / RG1) x amp gain.Therefore:
V OUT = (GAIN)(R SENSE )(I LOAD )
where GAIN = 20 for MAX437_T.GAIN = 50 for MAX437_F.GAIN = 100 for MAX437_H.
the appropriate gain version of the MAX4376/MAX4377/MAX4378.
Applications Information
Recommended Component Values
The MAX4376/MAX4377/MAX4378 sense a wide variety of currents with different sense resistor values. Table 1lists common resistor values for typical operation of the MAX4376/MAX4377/MAX4378.
Choosing R SENSE
To measure lower currents more accurately, use a high value for R SENSE . The high value develops a higher sense voltage that reduces offset voltage errors of the internal op amp.
I n applications monitoring very high currents, R SENSE must be able to dissipate the I 2R losses. If the resistor ’s rated 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.
If I SENSE has a large high-frequency component, mini-mize the inductance of R SENSE . Wire-wound resistors have the highest inductance, metal-film resistors are somewhat better, and low-inductance metal-film resis-tors are best suited for these applications.
Bidirectional Current-Sense Amplifier
Systems such as laptop computers and other devices that have internal charge circuitry require a precise bidirectional current-sense amplifier to monitor accu-rately the battery ’s current regardless of polarity. Figure 2 shows the MAX4377 used as a bidirectional current
Pin Description
M A X 4376/M A X 4377/M A X 4378
Single/Dual/Quad, High-Side Current-Sense Amplifiers with Internal Gain 8_______________________________________________________________________________________
Current Source Circuit
Figure 3 shows a block diagram using the MAX4376with a switching regulator to make a current source.
Figure 2. Bidirectional Current Monitor
Single/Dual/Quad, High-Side Current-Sense
Amplifiers with Internal Gain
MAX4376/MAX4377/MAX4378
Maxim cannot assume re sponsibility for use of any circuitry othe r than circuitry e ntire ly e mbodie d in a Maxim product. No circuit pate nt lice nse s are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
9_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600?2004 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
Typical Operating Circuit
Ordering Information (continued)
Chip Information
MAX4376_ TRANSISTOR COUNT: 162MAX4377_ TRANSISTOR COUNT: 324MAX4378_ TRANSISTOR COUNT: 648PROCESS: BiCMOS