19-1781; Rev 3; 5/04 Single/Dual/Quad, High-Side Current-Sense Amplifiers with Internal Gain Features 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 current monitoring is critical. These precision devices are offered in three fixed-gain versions of 20, 50, and 100: GAIN SUFFIX 20 T 50 F 100 H For example, MAX4376TAUK is a single high-side amplifier with a gain of 20. 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 input common-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 resistor. This capability offers a high level of integration and flexibility, resulting in a simple and compact currentsense solution. The MAX4376/MAX4377/MAX4378 operate over a supply voltage range of +3V to +28V, draw 1mA of supply current per amplifier, and operate over the full automotive 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 package. The MAX4377/MAX4378 are available in spacesaving 8-pin µMAX and 14-pin TSSOP packages, respectively. ♦ Low-Cost, Single/Dual/Quad, High-Side CurrentSense Amplifiers ♦ ±0.5% Typical Full-Scale Accuracy ♦ +3V to +28V Supply Operation ♦ Adjustable Current-Sense Capability with External Sense Resistor ♦ Buffered Output Voltage with 2mA Drive ♦ 1mA (typ) Supply Current ♦ 2.0MHz Bandwidth (Gain = +20V/V) ♦ Automotive Temperature Range (-40°C to +125°C) ♦ Full 0 to 28V Common-Mode Range, Independent of Supply Voltage ♦ Three Gain Versions Available +20V/V (MAX437_T) +50V/V (MAX437_F) +100V/V (MAX437_H) ♦ Available in Space-Saving 5-Pin SOT23 (Single), 8-Pin µMAX (Dual), and 14-Pin TSSOP (Quad) Ordering Information PART GAIN (+V/V) TEMP RANGE PINPACKAGE TOP MARK MAX4376 T AUK-T 20 -40°C to +125°C 5 SOT23-5 ADOG MAX4376FAUK-T 50 -40°C to +125°C 5 SOT23-5 ADOH MAX4376HAUK-T 100 -40°C to +125°C 5 SOT23-5 ADOI MAX4376TASA 20 -40°C to +125°C 8 SO — MAX4376FASA 50 -40°C to +125°C 8 SO — MAX4376HASA 100 -40°C to +125°C 8 SO — Ordering Information continued at end of data sheet. Pin Configurations TOP VIEW Applications OUT 1 Notebook Computers Current-Limited Power Supplies Fuel Gauges in PC General-System/BoardLevel Current Monitoring Battery Chargers Portable/Battery-Powered Systems Cell Phones Smart Battery Packages Automotive Current Detect Power Management Systems PA Bias Control GND 2 5 RS- 4 RS+ MAX4376 VCC 3 SOT23 Pin Configurations continued at end of data sheet. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX4376/MAX4377/MAX4378 General Description MAX4376/MAX4377/MAX4378 Single/Dual/Quad, High-Side Current-Sense Amplifiers with Internal Gain ABSOLUTE MAXIMUM RATINGS VCC, RS+, RS- to GND ...........................................-0.3V to +30V OUT to GND ...............................................-0.3V to (VCC + 0.3V) Differential Input Voltage (VRS+ - VRS- ).................................±8V Output Short Circuit to VCC ........................................Continuous Output Short Circuit to GND .....................................................1s Current into Any Pin..........................................................±20mA Continuous Power Dissipation (TA = +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 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 (VRS+ = 0 to 28V, VSENSE = (VRS+ - VRS- ) = 0V, VCC = +3.0V to +28V, RL = ∞, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = 25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP UNITS VCC Guaranteed by PSR test 3 28 V Common-Mode Input Range VCM Guaranteed by total OUT voltage error test 0 28 V Common-Mode Rejection CMR 2.2 mA 8 µA Supply Current per Amplifier Leakage Current ICC IRS+, IRSIRS+ Input Bias Current IRSFull-Scale Sense Voltage 2V ≤ VRS+ ≤ 28V, VSENSE = 100mV 90 VSENSE = 5mV, VRS+ > 2.0V, VCC = 12V 1 VCC = 0V, VRS+ = 28V 0 VRS+ ≤ 2.0V -400 60 VRS+ > 2.0V 0 120 VRS+ ≤ 2.0V -800 VSENSE 60 OUT High Voltage (Note 4) OUT Low Voltage ±0.5 ±3.25 ±11 VSENSE = 100mV, VCC = 28V, VRS+ = 28V, TA = +25°C ±0.5 ±5 VSENSE = 100mV, VCC = 12V, VRS+ = 0.1V ±9 ±32 VSENSE = 6.25mV, VCC = 12V, VRS+ = 12V (Note 3) ±7 (VCC - VOUT) VCC = 3V, IOUT = 2mA VOL mV ±6.75 VSENSE = 100mV, VCC = 28V, VRS+ = 28V IOUT ≤ 2mA IOUT = 200µA, VCC = VRS+ = 12V, VSENSE = 0V, TA = +25°C µA 120 150 VSENSE = 100mV, VCC = 12V, TA = +25°C Total OUT Voltage Error (Note 2) dB VRS+ > 2.0V VSENSE = 100mV, VCC = 12V, VRS+ = 12V 2 MAX Operating Voltage Range % 0.9 1.2 V 25 40 mV _______________________________________________________________________________________ Single/Dual/Quad, High-Side Current-Sense Amplifiers with Internal Gain (VRS+ = 0 to 28V, VSENSE = (VRS+ - VRS- ) = 0V, VCC = +3.0V to +28V, RL = ∞, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = 25°C.) (Note 1) PARAMETER Bandwidth SYMBOL BW Slew Rate Gain TYP VSENSE = 100mV (gain = +20V/V) 2 VSENSE = 100mV (gain = +50V/V) 1.7 VSENSE = 100mV (gain = +100V/V) 1.2 VSENSE = 6.25mV (Note 3) 0.5 VSENSE = 20mV to 100mV, CLOAD = 15pF AV MAX437_T MAX437_F +50 MAX437_H +100 OUT Setting Time to 1% of Final Value Maximum Capacitive Load VCC = 12V VRS+ = 12V CLOAD = 15pF MIN SR ∆AV Gain Accuracy CONDITIONS VSENSE = 10mV to 150mV, VCC = 12V, IOUT = 2mA, gain = 20 and 50 UNITS MHz 10 V/µs +20 TA = TMIN to TMAX V/V ±5.5 ±0.5 TA = +25°C ±2.5 % VSENSE = 10mV to 150mV, VCC = 20V, IOUT = 2mA, gain = 100 VCC = 12V, VRS+ = 12V, CLOAD = 15pF CLOAD MAX TA = TMIN to TMAX 5.5 TA = +25°C ±0.5 VSENSE = 6.25mV to 100mV 400 VSENSE = 100mV to 6.25mV 800 ±2.5 ns No sustained oscillation Output Resistance ROUT VSENSE = 100mV Power-Supply Rejection PSR VRS+ > 2V, VOUT = 1.6V, VCC = 3V to 28V 66 1000 pF 5 Ω 90 dB Power-Up Time to 1% of Final Value VSENSE = 100mV, CLOAD = 15pF 2 µs Saturation Recovery Time to 1% of Final Value VCC = 12V, VRS+ = 12V, CLOAD = 15pF, VSENSE = 100mV 1 µs Reverse Recovery Time to 1% of Final Value VCC = 12V, VRS_ = 12V, CLOAD = 15pF, VSENSE = -100mV to +100mV 1 µs Note 1: Note 2: Note 3: Note 4: All devices are 100% production tested at TA = +25°C. All temperature limits are guaranteed by design. Total OUT Voltage Error is the sum of gain and offset errors. 6.25mV = 1/16 of 100mV full-scale sense voltage. VSENSE such that VOUT is in saturation. _______________________________________________________________________________________ 3 MAX4376/MAX4377/MAX4378 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (VCC = VRS+ = 12V, VSENSE = 100mV, TA = +25°C.) SUPPLY CURRENT (PER AMPLIFIER) vs. TEMPERATURE 1.2 0.85 MAX4376T 0.80 MAX4376H 0.75 0.70 0.65 1.0 1.0 MAX4376F 0.8 MAX4376T 0.6 0.4 0.60 MAX4376F 0.4 0.2 0.0 -0.2 -0.4 MAX4376H -0.8 0 0.50 10 15 20 25 -1.0 -50 30 -25 0 25 50 75 5 10 MAX4376H 4 3 MAX4376F 2 1 0 MAX4376T 15 20 TOTAL OUTPUT ERROR vs. COMMON-MODE VOLTAGE 1.0 0.8 TOTAL OUTPUT ERROR (%) 5 MAX4376/7/8 toc04 6 TOTAL OUTPUT ERROR (%) 0 SUPPLY VOLTAGE (V) TOTAL OUTPUT ERROR vs. SUPPLY VOLTAGE (VSENSE = 6.25mV) 0.6 0.4 MAX4376H 0.2 0 -0.2 -0.4 -2 -0.6 -3 -0.8 MAX4376F MAX4376T -1.0 -4 5 10 15 20 25 5 10 15 20 25 SUPPLY VOLTAGE (V) COMMON-MODE VOLTAGE (V) GAIN ACCURACY vs. TEMPERATURE TOTAL OUTPUT ERROR vs. TEMPERATURE MAX4376/7/8 toc06 2.0 1.5 1.0 MAX4376H MAX4376F 0.5 0 -0.5 0 30 MAX4376T -1.0 1.0 0.8 TOTAL OUTPUT ERROR (%) 0 GAIN ACCURACY (%) 125 TEMPERATURE (°C) SUPPLY VOLTAGE (V) -1 100 MAX4376/7/8 toc05 5 0.6 MAX4376F 0.4 30 MAX4376/7/8 toc07 0 MAX4376T 0.2 0 -0.2 MAX4376H -0.4 -0.6 -1.5 -0.8 -1.0 -2.0 -50 -25 0 25 50 75 TEMPERATURE (°C) 4 MAX4376T 0.6 -0.6 0.2 0.55 0.8 MAX4376/7/8 toc03 MAX4376F 1.2 MAX4376/7/8 toc02 0.90 SUPPLY CURRENT (mA) MAX4376H 0.95 1.4 MAX4376/7/8 toc01 1.00 TOTAL OUTPUT ERROR vs. SUPPLY VOLTAGE (VSENSE = 100mV) TOTAL OUTPUT ERROR (%) SUPPLY CURRENT (PER AMPLIFIER) vs. SUPPLY VOLTAGE SUPPLY CURRENT (mA) MAX4376/MAX4377/MAX4378 Single/Dual/Quad, High-Side Current-Sense Amplifiers with Internal Gain 100 125 -50 -25 0 25 50 75 100 125 150 TEMPERATURE (°C) _______________________________________________________________________________________ 25 30 Single/Dual/Quad, High-Side Current-Sense Amplifiers with Internal Gain MAX4376/7/8 toc08 5 TOTAL OUTPUT ERROR (%) 4 MAX4376 toc09 MAX4376T SMALL-SIGNAL TRANSIENT RESPONSE (VSENSE = 95mV TO 100mV) TOTAL OUTPUT ERROR vs. FULL-SCALE SENSE VOLTAGE CL = 15pF RL =1kΩ IN 5mV/div 3 100mV 95mV 2 MAX4376H MAX4376F 1 2.0V 0 OUT 50mV/div -1 1.9V MAX4376T -2 50 100 VSENSE (mV) 150 200 2µs/div MAX4376F SMALL-SIGNAL TRANSIENT RESPONSE (VSENSE = 95mV TO 100mV) MAX4376 toc10 MAX4376H SMALL-SIGNAL TRANSIENT RESPONSE (VSENSE = 95mV to 100mV) CL = 15pF RL = 2.5kΩ IN 5mV/div 100mV 95mV MAX4376 toc11 0 CL = 15pF RL = 5kΩ IN 5mV/div 95mV 5V OUT 100mV/div 100mV 10V OUT 200mV/div 4.75V 9.5V MAX4376T LARGE-SIGNAL TRANSIENT RESPONSE (VSENSE = 6mV to 100mV) MAX4376F LARGE-SIGNAL TRANSIENT RESPONSE (VSENSE = 6mV to 100mV) CL = 15pF RL = 1kΩ IN 45mV/div MAX4376 toc13 2µs/div MAX4376 toc12 2µs/div CL = 15pF RL = 2.5kΩ 100mV 6mV IN 45mV/div 100mV 6mV 2V 5V OUT 500mV/div OUT 2V/div 0.3V 0.120V 2µs/div 2µs/div _______________________________________________________________________________________ 5 MAX4376/MAX4377/MAX4378 Typical Operating Characteristics (continued) (VCC = VRS+ = 12V, VSENSE = 100mV, TA = +25°C.) Typical Operating Characteristics (continued) (VCC = VRS+ = 12V, VSENSE = 100mV, TA = +25°C.) MAX4376H LARGE-SIGNAL TRANSIENT RESPONSE (VSENSE = 6mV to 100mV) CL = 15pF RL = 5kΩ IN 45mV/div 45 MAX4376H 40 100mV 35 6mV 10V GAIN (dB) 30 OUT 3V/div MAX4376/7/8 toc15 SMALL-SIGNAL GAIN vs. FREQUENCY MAX4376 toc14 MAX4376F 25 MAX4376T 20 15 10 0.6V 5 0 1.E+04 2µs/div 1.E+05 1.E+06 1.E+07 FREQUENCY (Hz) OUTPUT LOW vs. TEMPERATURE OVERDRIVE RESPONSE AV = +20V/V MAX4376/7/8 toc16 350 750mV IN 200mV/div MAX4376/7/8 toc17 400 300 350mV VOH OUT 2V/div OUTPUT LOW (mV) MAX4376/MAX4377/MAX4378 Single/Dual/Quad, High-Side Current-Sense Amplifiers with Internal Gain 250 MAX4376T 200 MAX4376F 150 100 7V MAX4376H 50 0 TIME (500ns) -50 -25 0 25 50 75 TEMPERATURE (°C) 6 _______________________________________________________________________________________ 100 125 Single/Dual/Quad, High-Side Current-Sense Amplifiers with Internal Gain PIN MAX4376 SOT23-5 MAX4376 MAX4377 MAX4378 SO-8 µMAX-8/ SO-8 SO-14/ TSSOP-14 NAME FUNCTION Output Voltage. VOUT_ is proportional to the magnitude of the sense voltage (VRS+ - VRS-). VOUT_ is approximately zero when VRS - > VRS - + (no phase reversal). 1 4 1, 7 1, 7, 8, 14 OUT, OUT_ 2 3 4 11 GND Ground 3 1 8 4 VCC Supply Voltage 4 8 3, 5 3, 5, 10, 12 RS+, RS_+ Power connection to the external sense resistor 5 6 2, 6 2, 6, 9, 13 RS-, RS_- Load-side connection to the external sense resistor — 2, 5, 7 — — Detailed Description The MAX4376/MAX4377/MAX4378 high-side currentsense 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 (VCC). The MAX4376/MAX4377/MAX4378 operate as follows: current from the source flows through RSENSE 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 VSOURCE - (ILOAD)(RSENSE). 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 RG1 flows through RG1, I RG1 = (ILOAD)(RSENSE)/RG1. The internal current mirror multiplies IRG1 by a current gain factor, β, to give IRGD = β x I RG1 . Solving I RGD = β x (I LOAD )(R SENSE )/RG1. Therefore: VOUT = β x (RGD/RG1)(RSENSE x ILOAD) x amp gain where amp gain is 2, 5, or 10. The part’s gain equals (β x RGD / RG1) x amp gain. N.C. No Connection. Not internally connected. Set the full-scale output range by selecting RSENSE and 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 1 lists common resistor values for typical operation of the MAX4376/MAX4377/MAX4378. Choosing RSENSE To measure lower currents more accurately, use a high value for RSENSE. The high value develops a higher sense voltage that reduces offset voltage errors of the internal op amp. In applications monitoring very high currents, RSENSE must be able to dissipate the I2R 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 maximum ratings. If ISENSE has a large high-frequency component, minimize the inductance of RSENSE. Wire-wound resistors have the highest inductance, metal-film resistors are somewhat better, and low-inductance metal-film resistors are best suited for these applications. Bidirectional Current-Sense Amplifier Therefore: VOUT = (GAIN)(RSENSE)(ILOAD) where GAIN = 20 for MAX437_T. GAIN = 50 for MAX437_F. GAIN = 100 for MAX437_H. Systems such as laptop computers and other devices that have internal charge circuitry require a precise bidirectional current-sense amplifier to monitor accurately the battery’s current regardless of polarity. Figure 2 shows the MAX4377 used as a bidirectional current _______________________________________________________________________________________ 7 MAX4376/MAX4377/MAX4378 Pin Description MAX4376/MAX4377/MAX4378 Single/Dual/Quad, High-Side Current-Sense Amplifiers with Internal Gain Table 1. Recommended Component Values FULL-SCALE LOAD CURRENT, ILOAD (A) CURRENT-SENSE RESISTOR, RSENSE (mΩ) 0.1 1000 1 100 5 20 10 10 RSENSE VSOURCE 20 2.0 50 5.0 100 10.0 20 2.0 50 5.0 100 10.0 20 2.0 50 5.0 100 10.0 20 2.0 50 100 5.0 10.0 ILOAD TO LOAD BATTERY RSENSE 0 TO +28V RS+ RG1 VCC BATTERY RS- IRG1 +3V TO +28V FULL-SCALE OUTPUT VOLTAGE (FULL-SCALE VSENSE = 100mV), VOUT (V) GAIN (+V/V) RG2 +3V TO +28V SYSTEM AND CHARGER MAX4376 VCC RS1+ A1 OUT1 RS1- OUT CURRENT MIRROR IRGD VOUT MAX4377 AV = 2, 5, OR 10 OUT RS2RGD OUT2 GND RS2+ Figure 1. Functional Diagram monitor. This is useful for implementing either smart battery packs or fuel gauges. Current Source Circuit Figure 2. Bidirectional Current Monitor Figure 3 shows a block diagram using the MAX4376 with a switching regulator to make a current source. 8 _______________________________________________________________________________________ Single/Dual/Quad, High-Side Current-Sense Amplifiers with Internal Gain VIN MAX1745 LOW-COST SWITCHING REGULATOR 0 TO +18V MAX4376_ TRANSISTOR COUNT: 162 MAX4377_ TRANSISTOR COUNT: 324 MAX4378_ TRANSISTOR COUNT: 648 PROCESS: BiCMOS RSENSE RS+ VCC +3V TO +28V RS- 0.1µF MAX4376 LOAD/ BATTERY OUT GND Figure 3. Current Source Pin Configurations (continued) TOP VIEW VCC 1 8 RS+ OUT1 1 7 N.C. RS1- 2 3 6 RS- RS1+ OUT 4 5 N.C. GND N.C. 2 GND MAX4376 8 VCC OUT1 1 7 OUT2 RS1- 2 3 6 RS2- RS1+ 4 5 RS2+ SO MAX4377 14 OUT4 MAX4378 13 RS4- 3 12 RS4+ VCC 4 11 GND RS2+ 5 10 RS3+ RS2- 6 9 RS3- 7 8 OUT3 µMAX/SO OUT2 SO/TSSOP Ordering Information (continued) GAIN (+V/V) TEMP RANGE MAX4377 T AUA 20 -40°C to +125°C 8 µMAX — MAX4377FAUA 50 -40°C to +125°C 8 µMAX — MAX4377HAUA 100 -40°C to +125°C 8 µMAX — MAX4377TASA 20 -40°C to +125°C 8 SO — MAX4377FASA 50 -40°C to +125°C 8 SO — MAX4377HASA 100 -40°C to +125°C 8 SO — MAX4378 T AUD 20 -40°C to +125°C 14 TSSOP — MAX4378FAUD 50 -40°C to +125°C 14 TSSOP — MAX4378HAUD 100 -40°C to +125°C 14 TSSOP — MAX4378TASD 20 -40°C to +125°C 14 SO — PART PINPACKAGE TOP MARK MAX4378FASD 50 -40°C to +125°C 14 SO — MAX4378HASD 100 -40°C to +125°C 14 SO — Typical Operating Circuit ILOAD VSENSE 0 TO +28V RSENSE +3V TO +28V RS+ VCC RS- 0.1µF MAX4376T/F/H A/D CONVERTER LOAD/ BATTERY OUT GND 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. 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. MAX4376/MAX4377/MAX4378 Chip Information ILOAD VSENSE