19-2048; Rev 0; 4/01 Low-Cost, SC70, Voltage-Output, High-Side Current-Sense Amplifier Features ♦ Low-Cost, Compact, Current-Sense Solution ♦ Three Gain Versions Available +20V/V (MAX4073T) +50V/V (MAX4073F) +100V/V (MAX4073H) ♦ ±1.0% Full-Scale Accuracy ♦ 500µA Supply Current ♦ Wide 1.8MHz Bandwidth ♦ +3V to +28V Operating Supply ♦ Wide +2V to +28V Common-Mode Range Independent of Supply Voltage ♦ Automotive Temperature Range (-40°C to +125°C) ♦ Available in Space-Saving 5-Pin SC70 Package Typical Operating Circuit RSENSE +3V TO +28V Applications Cell Phones Notebook Computers Portable/Battery-Powered Systems Smart Battery Packs/Chargers PDAs Power Management Systems PA Bias Control General System/Board-Level Current Monitoring Precision Current Sources ILOAD VSENSE +2V TO +28V RS+ VCC RS- 0.1µF MAX4073T/F/H A/D CONVERTER LOAD/ BATTERY OUT GND Pin Configurations appear at end of data sheet. Ordering Information PART TEMP. RANGE PIN-PACKAGE MAX4073TAXK-T -40°C to +125°C 5 SC70-5 GAIN (V/V) 20 TOP MARK ACM MAX4073TAUT-T -40°C to +125°C 6 SOT23-6 20 AAUE MAX4073FAXK-T -40°C to +125°C 5 SC70-5 50 ACN MAX4073FAUT-T -40°C to +125°C 6 SOT23-6 50 AAUF MAX4073HAXK-T -40°C to +125°C 5 SC70-5 100 ACO MAX4073HAUT-T -40°C to +125°C 6 SOT23-6 100 AAUG ________________________________________________________________ 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 MAX4073T/F/H General Description The MAX4073 low-cost, high-side current-sense amplifier features a voltage output that eliminates the need for gain-setting resistors making it ideal for cell phones, notebook computers, PDAs, and other systems where current monitoring is crucial. High-side current monitoring does not interfere with the ground path of the battery charger making the MAX4073 particularly useful in battery-powered systems. The input common-mode range of +2V to +28V is independent of the supply voltage. The MAX4073’s wide 1.8MHz bandwidth makes it suitable for use inside battery-charger control loops. The combination of three gain versions and a selectable external-sense resistor sets the full-scale current reading. The MAX4073 offers a high level of integration, resulting in a simple and compact current-sense solution. The MAX4073 operates from a +3V to +28V single supply and draws only 0.5mA of supply current. This device is specified over the automotive operating temperature range (-40°C to +125°C) and is available in a space-saving 5-pin SC70 package (half the size of the SOT23). For a similar device in a 6-pin SOT23 with a wider common-mode voltage range (0 to +28V), see the MAX4173 data sheet. MAX4073T/F/H Low-Cost, SC70, Voltage-Output, High-Side Current-Sense Amplifier ABSOLUTE MAXIMUM RATINGS VCC to GND ............................................................-0.3V to +30V RS+, RS- to GND....................................................-0.3V to +30V OUT to GND ...............................................-0.3V to (VCC + 0.3V) Output Short-Circuit to GND ......................................Continuous Differential Input Voltage (VRS+ - VRS-) .................................±5V Current Into Any Pin..........................................................±20mA Continuous Power Dissipation (TA = +70°C) 5-pin SC70 (derate 2.27mW/°C above +70°C) ............200mW 6-pin SOT23 (derate 8.7mW/°C above +70°C)............696mW 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+ = +2V to +28V, VSENSE = (VRS+ - VRS-) = 0, VCC = +3V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER Operating Voltage Range SYMBOL CONDITIONS MIN TYP MAX UNITS V VCC (Note 2) 3 28 Common-Mode Input Range VCMR (Note 3) 2 28 Common-Mode Rejection CMR VSENSE = 100mV, VCC = 12V Supply Current Leakage Current Input Bias Current Full-Scale Sense Voltage ICC 90 VCC = 28V 0.5 1.2 mA VCC = 0, VRS+ = 28V 0.05 1 µA IRS+ 20 60 IRS- 40 120 IRS+/IRS- VSENSE VSENSE = (VRS+ - VRS-) 150 VSENSE = 100mV, VCC = 12V, VRS+ = 2V ±1.0 VSENSE = 100mV, VCC = 12V, VRS+ = 12V, TA = +25oC ±1.0 VSENSE = 100mV, VCC = 12V, VRS+ = 12V, TA = TMIN to TMAX Total OUT Voltage Error (Note 4) VSENSE = 100mV, VCC = 28V, VRS+ = 28V, TA = +25oC VSENSE = 6.25mV (Note 5); VCC = 12V, VRS+ = 12V OUT High Voltage VOS (VCC - VOH) VCC = VRS+ = 12V, VSENSE > 10mV VSENSE = 150mV mV ±5.0 % ±1.0 ±5.0 ±8.5 ±7.5 1.0 mV MAX4073T, VCC = 3V MAX4073F, VCC = 7.5V 0.8 MAX4073H, VCC = 15V 2 µA ±7.0 VSENSE = 100mV, VCC = 28V, VRS+ = 28V, TA = TMIN to TMAX Extrapolated Input Offset Voltage V dB _______________________________________________________________________________________ 1.2 V Low-Cost, SC70, Voltage-Output, High-Side Current-Sense Amplifier (VRS+ = +2V to +28V, VSENSE = (VRS+ - VRS-) = 0, VCC = +3V to +28V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER Bandwidth SYMBOL BW CONDITIONS VCC = 12V, VRS+ = 12V, CLOAD = 5pF MIN MAX4073T, VSENSE = 100mV 1.8 MAX4073F, VSENSE = 100mV 1.7 MAX4073H, VSENSE = 100mV 1.6 MAX4073T/F/H VSENSE = 6.25mV (Note 5) 600 MAX4073T AV Gain ∆AV Gain Accuracy MAX4073F 50 MAX4073H 100 VCC = 12V, TA = +25°C VRS+ = 12V, VSENSE = 10mV to 150mV, TA = TMIN to TMAX MAX4073T/F VCC = 12V VRS+ = 12V CLOAD = 5pF Output Resistance ROUT Power-Supply Rejection Ratio PSRR ±1.0 UNITS MHz kHz V/V ±4.5 ±6.5 % ±1.0 ±4.5 ±6.5 VSENSE = 6.25mV to 100mV 400 VSENSE = 100mV to 6.25mV 800 ns 12 VCC = 3V to 28V MAX 20 VCC = 12V, TA = +25°C VRS+ = 12V, VSENSE = 10mV to 100mV, TA = TMIN to TMAX MAX4073H OUT Settling Time to 1% of Final Value TYP VSENSE = 60mV, MAX4073T 70 78 VSENSE = 24mV, MAX4073F 70 85 VSENSE = 12mV, MAX4073H 70 90 kΩ dB Power-Up Time (Note 6) CLOAD = 5pF, VSENSE = 100mV 5 µs Saturation Recovery Time (Note 7) VCC = 12V, VRS+ = 12V, CLOAD = 5pF 5 µs Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: Note 7: All devices are 100% production tested at TA = +25°C. All temperature limits are guaranteed by design. Inferred from PSRR test. Inferred from OUT Voltage Error test. Total OUT Voltage Error is the sum of the gain and offset errors. 6.25mV = 1/16 of 100mV full-scale sense voltage. Output settles to within 1% of final value. The device will not experience phase reversal when overdriven. _______________________________________________________________________________________ 3 MAX4073T/F/H ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (VCC = +12V, VRS+ = +12V, VSENSE = 100mV, CL = 5pF, TA = +25°C, unless otherwise noted.) SUPPLY CURRENT vs. SUPPLY VOLTAGE 0.49 0.48 0.47 MAX4073T 0.46 1.1 1.0 MAX4073F 0.8 0.7 0.45 MAX4073T 0.6 VSENSE = 6.25mV 10 15 20 25 5 10 15 20 25 30 -50 0 25 50 75 100 SUPPLY CURRENT vs. VRS+ VOLTAGE OUTPUT HIGH VOLTAGE (VCC - VOH) vs. TEMPERATURE 0.51 MAX4073F 0.49 VSENSE = 100mV 1.50 MAX4073H 1.40 MAX4073T 0.48 0.8 1.30 0.7 1.20 1.10 MAX4073F 1.00 0.90 15 20 25 0.5 0.4 0.2 0.1 0 0 30 0.6 0.3 MAX4073T 0.60 10 VSENSE = 150mV 0.9 0.70 0.47 5 10 15 20 25 30 -50 -25 0 25 50 75 100 VRS+ (V) VRS+ (V) TEMPERATURE (°C) TOTAL OUTPUT ERROR vs. SUPPLY VOLTAGE TOTAL OUTPUT ERROR vs. SUPPLY VOLTAGE TOTAL OUTPUT ERROR vs. COMMON-MODE VOLTAGE MAX4073H 0.2 0 -0.2 -0.4 MAX4073T -0.6 VSENSE = 6.25mV 1.5 1.0 0.5 0 -0.5 -1.0 -1.0 10 15 20 SUPPLY VOLTAGE (V) 25 30 0.5 0 -0.5 -1.0 -1.5 -2.0 -3.0 -2.0 5 125 -2.5 -1.5 -0.8 1.0 TOTAL OUTPUT ERROR (%) 0.6 0.4 2.0 MAX4073 toc08 MAX4073F TOTAL OUTPUT ERROR (%) VSENSE = 100mV MAX 4073 toc07 1.0 125 1.0 VCC - VOH (V) 0.52 0.50 1.60 MAX4073 toc05 MAX4073H 0 -25 SUPPLY CURRENT vs. VRS+ VOLTAGE 0.80 4 0.1 TEMPERATURE (˚C) 0.53 0.8 0.2 SUPPLY VOLTAGE (V) VSENSE = 6.25mV 5 0.3 SUPPLY VOLTAGE (V) 0.54 0 0.4 0 0 30 SUPPLY CURRENT (mA) 5 MAX4073 toc04 0 0.5 VSENSE = 100mV 0.5 0.43 VSENSE = 0 VCC = +28V 0.6 MAX4073 toc09 0.44 SUPPLY CURRENT (mA) 1.2 0.9 0.7 MAX4073 toc06 MAX4073F MAX4073H 1.3 SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) 0.51 1.4 SUPPLY CURRENT (mA) MAX4073H 0.50 1.5 MAX4073 toc02 0.52 MAX4073 toc01 0.53 SUPPLY CURRENT vs. TEMPERATURE MAX4073 toc03 SUPPLY CURRENT vs. SUPPLY VOLTAGE TOTAL OUTPUT ERROR (%) MAX4073T/F/H Low-Cost, SC70, Voltage-Output, High-Side Current-Sense Amplifier 0 5 10 15 20 SUPPLY VOLTAGE (V) 25 30 0 5 10 15 20 25 COMMON-MODE VOLTAGE (V) _______________________________________________________________________________________ 30 Low-Cost, SC70, Voltage-Output, High-Side Current-Sense Amplifier (VCC = +12V, VRS+ = +12V, VSENSE = 100mV, CL = 5pF, TA = +25°C, unless otherwise noted.) 1.5 GAIN ACCURACY (%) VCC = +12V 0.4 0.2 0 -0.2 VCC = +28V -0.4 0 -0.5 5 -2.0 -25 0 25 50 75 0 -50 100 125 150 -25 TEMPERATURE (°C) 0 25 75 50 TEMPERATURE (°C) 100 125 0.1 1 10 100 FREQUENCY (kHz) 1000 10,000 MAX4073T SMALL-SIGNAL TRANSIENT RESPONSE POWER-SUPPLY REJECTION RATIO vs. FREQUENCY MAX4073 toc14 MAX4073 toc13 100 MAX4073H 90 100mV MAX4073F 80 PSRR (dB) 20 10 -1.5 -50 MAX4073T 25 15 -0.6 -1.0 MAX4073F 35 30 0.5 -1.0 -0.8 MAX4073H 40 1.0 MAX4073 toc12 VSENSE = (10mV - 100mV) GAIN (dB) 0.6 45 MAX4073 toc11 0.8 TOTAL OUTPUT ERROR (%) 2.0 MAX4073 toc10 1.0 SMALL-SIGNAL GAIN vs. FREQUENCY GAIN ACCURACY vs. TEMPERATURE TOTAL OUTPUT ERROR vs. TEMPERATURE VSENSE 2.5mV/div MAX4073T 70 95mV 60 2V 50 40 OUT 50mV/div 30 1.9V 20 0.1 1 10 100 1µs/div 1000 FREQUENCY (kHz) MAX4073H SMALL-SIGNAL TRANSIENT RESPONSE MAX4073F SMALL-SIGNAL TRANSIENT RESPONSE MAX4073 toc16 MAX4073 toc15 100mV 100mV VSENSE 2.5mV/div VSENSE 2.5mV/div 95mV 95mV 5V 10V OUT 125mV/div OUT 250mV/div 9.5V 4.75V 1µs/div 1µs/div _______________________________________________________________________________________ 5 MAX4073T/F/H Typical Operating Characteristics (continued) MAX4073T/F/H Low-Cost, SC70, Voltage-Output, High-Side Current-Sense Amplifier Typical Operating Characteristics (continued) (VCC = +12V, VRS+ = +12V, VSENSE = 100mV, CL = 5pF, TA = +25°C, unless otherwise noted.) MAX4073T LARGE-SIGNAL TRANSIENT RESPONSE MAX4073F LARGE-SIGNAL TRANSIENT RESPONSE MAX4073 toc17 MAX4073 toc18 100mV 100mV VSENSE 45mV/div VSENSE 45mV/div 6.25mV 6.25mV 2V 5V OUT 0.9V/div OUT 2.35V/div 0.120V 0.3V 1µs/div 1µs/div MAX4073H LARGE-SIGNAL TRANSIENT RESPONSE MAX4073T OVERDRIVE RESPONSE MAX4073 toc19 MAX4073 toc20 VCC = +3V 250mV 100mV VSENSE 100mV/div VSENSE 45mV/div 6.25mV 50mV 10V VOH OUT 4.7V/div OUT 600mV/div 0.6V 1V 1µs/div 1µs/div MAX4073T START-UP DELAY MAX4073 toc21 VCC = 0 to +4V 4V VCC 2V/div 0 2V OUT 1V/div 0 1µs/div 6 _______________________________________________________________________________________ Low-Cost, SC70, Voltage-Output, High-Side Current-Sense Amplifier PIN NAME FUNCTION SOT23-6 1, 2 SC70-5 2 GND Ground 3 3 VCC Supply Voltage Input. Bypass to GND with a 0.1µF capacitor. 4 4 RS+ Power-Side Connection to the External Sense Resistor 5 5 RS- Load-Side Connection to the External Sense Resistor 6 1 OUT Voltage Output. VOUT is proportional to VSENSE. Output impedance is approximately 12kΩ. Detailed Description The MAX4073 high-side current-sense amplifier features a +2V to +28V input common-mode range that is independent of supply voltage. This feature allows the monitoring of current out of a battery as low as +2V and also enables high-side current sensing at voltages greater than the supply voltage (VCC). The MAX4073 operates 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 (ILOAD)(RSENSE). Since IRG1 flows through RG1, IRG1 = (ILOAD)(RSENSE) / RG1. The internal current mirror multiplies I RG1 by a current gain factor, β, to give IRGD = β ✕ IRG1. Solving IRGD = β ✕ (ILOAD)(RSENSE) / RG1. Assuming infinite output impedance, VOUT = (IRGD) (RGD). Substituting in for IRGD and rearranging, VOUT = β ✕ (RGD / RG1)(RSENSE ✕ ILOAD). The parts gain equals β ✕ RGD / RG1. Therefore, VOUT = (GAIN) (RSENSE) (ILOAD), where GAIN = 20V/V for MAX4073T, GAIN = 50V/V for MAX4073F, and GAIN = 100V/V for MAX4073H. Set the full-scale output range by selecting RSENSE and the appropriate gain version of the MAX4073. Applications Information Recommended Component Values The MAX4073 senses a wide variety of currents with different sense resistor values. Table 1 lists common resistor values for typical operation of the MAX4073. Choosing RSENSE To measure lower currents more accurately, use a large value for RSENSE. The larger value develops a RSENSE VSOURCE +2V TO +28V +3V TO +28V VCC ILOAD TO LOAD/BATTERY RS+ IRG1 RS- RG1 RG2 A1 MAX4073T/F/H OUT CURRENT MIRROR VOUT IRGD RGD = 12kΩ GND Figure 1. Functional Diagram higher-sense voltage that reduces offset voltage errors of the internal op amp. Typical sense voltages range between 10mV and 150mV. 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 (±5V). If ISENSE has a large high-frequency component, minimize the inductance of RSENSE. Wire-wound resistors have the highest inductance, metal-film resistors are _______________________________________________________________________________________ 7 MAX4073T/F/H Pin Description MAX4073T/F/H Low-Cost, SC70, Voltage-Output, High-Side Current-Sense Amplifier somewhat better, and low-inductance metal-film resistors are best suited for these applications. For VSENSE = 100mV, full-scale output voltage can be 2V, 5V, or 10V depending on the gain. For proper operation, ensure VCC exceeds the full-scale output voltage by 1.2V (see Output High Voltage (V CC - V OH ) vs. Temperature in the Typical Operating Characteristics). INPUT LOAD/BATTERY RSENSE 0.3in COPPER 0.1in COPPER 0.3in COPPER _ + VSENSE RS+ RS- +3V TO +28V VCC 0.1µF Using a PCB Trace as RSENSE If the cost of RSENSE is an issue and accuracy is not critical, use the alternative solution shown in Figure 2. This solution uses copper PC board traces to create a sense resistor. The resistivity of a 0.1-inch-wide trace of 2-ounce copper is approximately 30mΩ/ft. The resistance-temperature coefficient of copper is fairly high (approximately 0.4%/°C), so systems that experience a wide temperature variance must compensate for this effect. In addition, do not exceed the maximum power dissipation of the copper trace. For example, the MAX4073T (with a maximum load current of 10A and an RSENSE of 5mΩ) creates a full-scale VSENSE of 50mV that yields a maximum VOUT of 1V. RSENSE in this case requires about 2 inches of 0.1 inchwide copper trace. Output Impedance The output of the MAX4073 is a current source driving a 12kΩ resistance. Resistive loading added to OUT reduces the output gain of the MAX4073. To minimize output errors for most applications, connect OUT to a high-impedance input stage. When output buffering is required, choose an op amp with a common-mode input range and an output voltage swing that includes ground when operating with a single supply. The op amp’s supply voltage range should be at least as high as any voltage the system may encounter. The percent error introduced by output loading is determined with the following formula: MAX4073T OUT GND Figure 2. MAX4073T Connections Showing Use of PC Board VIN LOW-COST SWITCHING REGULATOR ILOAD VSENSE +2V TO +28V RSENSE +3V TO +28V RS+ VCC RS- 0.1µF MAX4073T/F/H LOAD/ BATTERY OUT GND Figure 3. Current Source RLOAD %ERROR = 100 − 1 12kΩ + RLOAD where RLOAD is the external load applied to OUT. Current Source Circuit Figure 3 shows a block diagram using the MAX4073 with a switching regulator to make a current source. 8 _______________________________________________________________________________________ Low-Cost, SC70, Voltage-Output, High-Side Current-Sense Amplifier MAX4073T/F/H Table 1. Recommended Component Values FULL-SCALE LOAD CURRENT ILOAD (A) CURRENT-SENSE RESISTOR RSENSE (mΩ) GAIN FULL-SCALE OUTPUT VOLTAGE (FULL-SCALE VSENSE = 100mV) VOUT (V) 20 2.0 0.1 1000 50 5.0 100 10.0 20 2.0 1 100 5 20 10 10 50 5.0 100 10.0 20 2.0 50 5.0 100 10.0 20 2.0 50 5.0 100 10.0 Pin Configurations TOP VIEW OUT 1 GND 2 5 RS- MAX4073T/F/H VCC 3 GND 1 GND 2 4 RS+ SC70-5 MAX4073T/F/H VCC 3 6 OUT 5 RS- 4 RS+ SOT23-6 Chip Information TRANSISTOR COUNT: 187 PROCESS: Bipolar _______________________________________________________________________________________ 9 Low-Cost, SC70, Voltage-Output, High-Side Current-Sense Amplifier 6LSOT.EPS SC70, 5L.EPS MAX4073T/F/H Package Information 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. 10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.