19-5015; Rev 4; 7/11 KIT ATION EVALU E L B AVAILA -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers Features o -20V to +75V Input Common-Mode Voltage Range o 400µV (max) Input Offset Voltage o 0.6% (max) Gain Accuracy Error The MAX9918/MAX9919/MAX9920 are single-supply, high-accuracy current-sense amplifiers with a high input common-mode range that extends from -20V to +75V. These amplifiers are well suited for current monitoring of inductive loads such as motors and solenoids, where common-mode voltages can become negative due to inductive kickback, reverse-battery conditions, or transient events. The MAX9918/MAX9920 feature adjustable gain set by an external resistive-divider network. The MAX9919 features fixed gains of 45V/V (MAX9919F) and 90V/V (MAX9919N). The MAX9918/MAX9919/MAX9920 operate as unidirectional amplifiers when VREFIN = GND and as bidirectional amplifiers when VREFIN = VCC/2. The MAX9920 attenuates the input signal by a factor of 4 at the input level-shifting stage allowing the device to sense voltages up to 200mV (unidirectional operation) or ±100mV (bidirectional operation). o o o o o Uni- or Bidirectional Current Sensing Reference Input for Bidirectional OUT 120kHz, -3dB Bandwidth (MAX9919N) Single-Supply Operation (4.5V to 5.5V) 1mA Supply Current o 0.5µA (typ) Shutdown Current o Rail-to-Rail Output o -40°C to +125°C Automotive Temperature Range Ordering Information/ Selector Guide VSENSE (mV) GAIN (V/V) PINPACKAGE ±50 Adjustable 8 SOIC-EP* MAX9918ASA/V+ ±50 Adjustable 8 SOIC-EP* MAX9919FASA+ ±50 45 8 SOIC-EP* H-Bridge Motor Current Sensing Solenoid Current Sensing MAX9919NASA+ ±50 90 8 SOIC-EP* MAX9919NASA/V+ ±50 90 8 SOIC-EP* Current Monitoring of Inductive Loads High- and Low-Side Precision Current Sensing 4x4 Transmission Control MAX9920ASA+ ±200 Adjustable 8 SOIC-EP* MAX9920ASA/V+ ±200 Adjustable 8 SOIC-EP* The MAX9918/MAX9919/MAX9920 operate with a single 5V supply voltage, are fully specified over the -40°C to +125°C automotive temperature range, and are available in an 8-pin SOIC package. PART MAX9918ASA+ Applications Note: All devices operate over the -40°C to +125°C temperature range. +Denotes a lead(Pb)-free/RoHS-compliant package. /V denotes an automotive qualified part. *EP = Exposed pad. Electronic Throttle Control Super-Capacitor Charge/Discharge Monitoring in Hybrid Cars Precision High-Voltage Current Monitoring Typical Operating Circuit VCC VCC VBATT φ2B φ1A MAX9918 MAX9920 RSENSE A OUT R2 M FB RS+ RSφ2B ADC INPUT STAGE LEVEL SHIFTER R1 REFIN REF ADJUSTABLE GAIN φ1B SHDN GND μC GND ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX9918/MAX9919/MAX9920 General Description MAX9918/MAX9919/MAX9920 -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers ABSOLUTE MAXIMUM RATINGS VCC to GND ..............................................................-0.3V to +6V RS+, RS- to GND (VCC = 5V) ..................................-30V to +80V RS+, RS- to GND (VCC = 0V) .............-15V to +80V (15 minutes) Differential Input Voltage (VRS+ - VRS-) (MAX9918/MAX9919).................................±15V (Continuous) Differential Input Voltage (VRS+ - VRS-) (MAX9920) .............................±5V (Continuous) REFIN, FB, OUT to GND.............................-0.3V to (VCC + 0.3V) SHDN to GND.........................................................-0.3V to +20V Output Short Circuit to VCC or GND...........................Continuous Continuous Current into Any Pin (Not to exceed package power dissipation) ................±20mA Continuous Power Dissipation (TA = +70°C) 8-Pin SOIC-EP (derate 24.4mW/°C above +70°C) .1951.2mW** Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Soldering Temperature (reflow) .......................................+260°C **As per JEDEC51 Standard (multilayer board). PACKAGE THERMAL CHARACTERISTICS (Note 1) SOIC-EP Junction-to-Ambient Thermal Resistance (θJA) ...........41°C/W Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a fourlayer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. 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 = 5V, VRS+ = VRS- = +14V, VSENSE = (VRS+ - VRS-) = 0V, VSHDN = VGND = 0V, VREFIN = VCC/2, RL = 100kΩ; for MAX9918, AV = 90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, AV = 20V/V, R2/R1 = 79kΩ/1kΩ; TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS VRS+ = VRS- = +14V, VREFIN = 0V MAX9918 VRS+ = VRS- = -2V, VREFIN = 0V VRS+ = VRS- = +14V, VREFIN = 0V Input Offset Voltage (Note 2) VOS MAX9919_ VRS+ = VRS- = -2V, VREFIN = 0V VRS+ = VRS- = +14V, VREFIN = 0V MAX9920 VRS+ = VRS- = -2V, VREFIN = 0V 2 MIN TA = +25°C TYP MAX ±0.14 ±0.4 TA = -40°C to +125°C TA = +25°C ±0.7 ±0.08 TA = -40°C to +125°C TA = +25°C ±0.18 ±0.11 ±0.4 ±1.0 ±0.48 TA = -40°C to +125°C TA = +25°C ±0.4 ±0.9 TA = -40°C to +125°C TA = +25°C ±0.4 ±1.3 TA = -40°C to +125°C TA = +25°C UNITS ±1.2 ±3.0 ±0.10 TA = -40°C to +125°C _______________________________________________________________________________________ ±0.9 ±3.5 mV -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers (VCC = 5V, VRS+ = VRS- = +14V, VSENSE = (VRS+ - VRS-) = 0V, VSHDN = VGND = 0V, VREFIN = VCC/2, RL = 100kΩ; for MAX9918, AV = 90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, AV = 20V/V, R2/R1 = 79kΩ/1kΩ; TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETERS SYMBOL CONDITIONS MAX9918 Input Offset Voltage Drift (Note 3) VOSD MAX9919_ MAX9920 Common-Mode Range VCM CMRR MAX9920 Input Bias Current IRS+, IRS- Input Offset Current -20V ≤ VCM ≤ +75V TYP VRS+ = VRS- = +14V ±1.2 VRS+ = VRS- = -2V ±3.3 VRS+ = VRS- = +14V ±1.8 VRS+ = VRS- = -2V ±1.8 VRS+ = VRS- = +14V ±2.4 VRS+ = VRS- = -2V Inferred from CMRR tests MAX9918, MAX9919 Common-Mode Rejection Ratio (Note 3) MIN -2V ≤ VCM ≤ +14V MAX μV/°C ±8.8 -20 +75 V 80 -20V ≤ VCM ≤ +75V 96 -2V ≤ VCM ≤ +14V 72 -20V ≤ VCM ≤ +75V 86 dB TA = +25°C ±175 TA = -40°C to +125°C ±250 (IRS+ - IRS-) UNITS 0 μA ±8 μA Input Leakage Current in Shutdown -20V ≤ VCM ≤ +75V, VSHDN = VCC = 5V ±30 μA Input Leakage Current VRS+ = VRS- = +14V, +75V, VCC = 0V ±30 μA MAX9918, MAX9919_ Input Resistance MAX9920 Full-Scale Sense Voltage (Note 4) Gain (Notes 2, 4) VSENSE G Minimum Adjustable Gain GADJ Inferred from gain error test Common mode 300 Differential 715 Ω Common mode 330 kΩ Differential 224 Ω MAX9918, MAX9919_ 50 MAX9920 200 MAX9918, MAX9920 Adj MAX9919F 45 MAX9919N 90 MAX9918 30 MAX9920 7.5 kΩ mV V/V V/V _______________________________________________________________________________________ 3 MAX9918/MAX9919/MAX9920 ELECTRICAL CHARACTERISTICS (continued) MAX9918/MAX9919/MAX9920 -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers ELECTRICAL CHARACTERISTICS (continued) (VCC = 5V, VRS+ = VRS- = +14V, VSENSE = (VRS+ - VRS-) = 0V, VSHDN = VGND = 0V, VREFIN = VCC/2, RL = 100kΩ; for MAX9918, AV = 90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, AV = 20V/V, R2/R1 = 79kΩ/1kΩ; TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS VRS+ = VRS- = +14V MAX9918 VRS+ = VRS- = -2V, VREFIN = 0V MAX9919F Gain Error (Note 2) GE MAX9919N VRS+ = VRS- = -2V, VREFIN = 0V FB Input Bias Current Output-Voltage High (Note 4) Output-Voltage Low (Note 4) Short-Circuit Current Output Resistance REFIN Voltage Range 4 IFB TA = +25°C ±0.08 ±0.6 ±0.02 TA = -40°C to +125°C UNITS ±0.6 ±1.0 ±0.13 ±0.45 ±1.2 TA = +25°C ±0.10 TA = -40°C to +125°C ±0.45 ±0.9 ±0.16 % ±0.6 ±1.2 TA = +25°C ±0.11 TA = -40°C to +125°C ±0.6 ±1.0 VRS+ = VRS- = TA = +25°C +14V, VREFIN = TA = -40°C to 0V +125°C ±0.29 ±1.0 ±1.7 TA = +25°C ±0.24 TA = -40°C to +125°C ±1.0 ±1.7 MAX9918, MAX9920 VSENSE = 200mV for MAX9918, MAX9919_, VCC - VOH VSENSE = 400mV for MAX9920 VSENSE = -200mV for MAX9918, MAX9919_, VOL VSENSE = -400mV for MAX9920 OUT shorted to VCC ISC OUT shorted to GND MAX ±1.2 VRS+ = VRS- = TA = +25°C +14V, VREFIN = TA = -40°C to 0V +125°C VRS+ = VRS- = -2V, VREFIN = 0V TYP TA = -40°C to +125°C, VREFIN = 0V VRS+ = VRS- = TA = +25°C +14V, VREFIN = TA = -40°C to 0V +125°C VRS+ = VRS- = -2V, VREFIN = 0V MAX9920 MIN TA = +25°C, VREFIN = 0V 5 15 RL = 100kΩ to GND 3 10 RL = 10kΩ to GND 12 40 RL = 100kΩ to VCC 3 10 RL = 10kΩ to VCC 10 40 nA mV mV 44 mA 41 ROUT Ω 0.1 MAX9918, MAX9919_ 0 VCC /2 VCC 1.9 MAX9920 0 VCC /2 VCC 2.4 Inferred from REFIN CMRR test V _______________________________________________________________________________________ -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers (VCC = 5V, VRS+ = VRS- = +14V, VSENSE = (VRS+ - VRS-) = 0V, VSHDN = VGND = 0V, VREFIN = VCC/2, RL = 100kΩ; for MAX9918, AV = 90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, AV = 20V/V, R2/R1 = 79kΩ/1kΩ; TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETERS REFIN Common-Mode Rejection Ratio REFIN Current SYMBOL SHDN Logic-High VIH SHDN Logic-Low VIL 0V ≤ VREFIN ≤ (VCC - 1.9V) 82 103 MAX9920 0V ≤ VREFIN ≤ (VCC - 2.4V) 75 90 VCC PSRR MAX9920, VRS+ = VRS- = ±200mV ±100 2.0 Inferred from PSRR test MAX9918, MAX9919_ 4.5V ≤ VCC ≤ 5.5V 74 103 MAX9920 4.5V ≤ VCC ≤ 5.5V 68 100 VRS+ = VRS- = -2V Small Signal -3dB Bandwidth Slew Rate ICC_SHDN BW SR 0.7 TA = -40°C to +125°C TA = +25°C 1.0 75 MAX9919F, VSENSE = 50mV 250 MAX9919N, VSENSE = 50mV 120 MAX9920, VSENSE = 200mV 230 MAX9918 0.6 MAX9919F 0.9 MAX9919N 3.0 MAX9920 1.5 MAX9919F 1% Settling Time from VSENSE Step MAX9919N MAX9920 VSENSE = 5mV to 50mV step V 5 μA 5.5 V dB 1.2 1.6 mA 2.2 0.5 MAX9918, VSENSE = 50mV MAX9918 0.8 1.5 TA = -40°C to +125°C VSHDN = VCC = 5V μA V 4.5 TA = +25°C UNITS dB ±100 ICC Shutdown Supply Current MAX MAX9918, MAX9919_, VRS+ = VRS- = ±50mV VRS+ = VRS- = +14V Supply Current TYP 0 ≤ VSHDN ≤ VCC SHDN Logic Input Current Power-Supply Rejection Ratio (Note 3) MIN MAX9918, MAX9919_ REFINCMRR IREFIN Supply Voltage Range CONDITIONS 10 μA kHz V/μs 12 VSENSE = 50mV to 5mV step 7 VSENSE = 5mV to 50mV step 3.5 VSENSE = 50mV to 5mV step 2.5 VSENSE = 5mV to 50mV step 3.5 VSENSE = 50mV to 5mV step 3 VSENSE = 20mV to 200mV step 5 VSENSE = 200mV to 20mV step 3 μs _______________________________________________________________________________________ 5 MAX9918/MAX9919/MAX9920 ELECTRICAL CHARACTERISTICS (continued) MAX9918/MAX9919/MAX9920 -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers ELECTRICAL CHARACTERISTICS (continued) (VCC = 5V, VRS+ = VRS- = +14V, VSENSE = (VRS+ - VRS-) = 0V, VSHDN = VGND = 0V, VREFIN = VCC/2, RL = 100kΩ; for MAX9918, AV = 90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, AV = 20V/V, R2/R1 = 79kΩ/1kΩ; TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETERS SYMBOL CONDITIONS MAX9918, VSENSE = 50mV MAX9919F, VSENSE = 50mV 1% Settling Time from VCM Step MIN VCM = -2V to +14V step 2.5 VCM = +14V to -2V step 0.5 VCM = -2V to +14V step 2.5 VCM = +14V to -2V step 0.5 MAX9919N, VSENSE = 50mV VCM = -2V to +14V step 3.5 VCM = +14V to -2V step 3.5 MAX9920, VSENSE = 200mV VCM = -2V to +14V step 0.25 VCM = +14V to -2V step 2.5 MAX9918, VSENSE = 50mV, 1% settling Power-Up Time Max Capacitive Load Stability Input Referred Noise Voltage Density 5 MAX9919N, VSENSE = 50mV, 1% settling 6 MAX9920, VSENSE = 200mV, 1% settling 5 10kHz MAX 50 μs μs pF MAX9918, MAX9919_ 60 MAX9920 174 Note 1: All devices are 100% production tested at TA = +25°C. All temperature limits are guaranteed by design. Note 2: VOS is extrapolated from two point gain error tests. Measurements are made at VSENSE = 5mV and 50mV for MAX9918/MAX9919N/MAX9919F, and VSENSE = 20mV and 200mV for MAX9920. Note 3: Extrapolated VOS as described above in Note 2 is used to calculate VOS drift, CMRR, and PSRR. Note 4: OUT should be 100mV away from either rail to achieve rated accuracy, or limited by a VSENSE of 50mV for the MAX9918/MAX9919N/MAX9919F and 200mV for the MAX9920. Note 5: Not production tested. Guaranteed by design. 6 UNITS 4.5 MAX9919F, VSENSE = 50mV, 1% settling No sustained oscillations (Note 5) en TYP _______________________________________________________________________________________ nV/√Hz -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers VOS (VRS+ = +14V) VOS DRIFT (VRS+ = +14V) 0.40 0.25 0.30 0.25 0.30 0.25 N (%) 0.20 N (%) 0.15 0.15 0.20 0.10 0.15 0.10 0.10 0.05 0.05 0.05 0 0 0 -4 80 160 240 320 400 -3 -2 -1 0 1 2 3 4 -400 -320 -240-160 -80 0 OFFSET VOLTAGE (FV/°C) OFFSET VOLTAGE (FV) VOS DRIFT (VRS+ = -2V) VOS vs. VCC VOS vs. VCM 0.40 0.35 400 TA = -40°C 300 TA = +25°C 125 100 75 200 0.25 0.20 0 -100 0.15 -200 0.10 -300 0.05 -400 0 -500 0 2 4 6 8 10 -20 -10 0 OFFSET VOLTAGE (FV/°C) 0 -25 TA = +125°C -50 -75 -100 10 20 30 40 50 60 70 80 0.8 0.7 MAX9918ASA VCC = 5V VREF = VGND VCM = -2V 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5 VCC (V) GAIN ERROR (VRS+ = +14V, MAX9919N, AV = +90V/V) MAX9918 toc07 0.5 25 VCM (V) GAIN ERROR (VRS+ = +14V, MAX9919F, AV = +45V/V) 0.6 MAX9918ASA VCC = 5V VREF = VGND GAIN ERROR (VRS+ = -2V, MAX9919F, AV = +45V/V) 0.6 MAX9918 toc08 -10 -8 -6 -4 -2 VCM = 14V 50 100 VOS (FV) VOS (uV) 0.30 MAX9918 toc06 500 MAX9918 toc04 0.45 80 160 240 320 400 OFFSET VOLTAGE (FV) MAX9918 toc05 -400 -320 -240-160 -80 0 N (%) 0.20 MAX9918 toc09 N (%) 0.35 0.35 MAX9918 toc03 0.45 MAX9918 toc02 0.30 MAX9918 toc01 0.50 VOS (VRS+ = -2V) 0.5 0.6 0.4 0.3 N (%) 0.5 N (%) N (%) 0.4 0.4 0.3 0.2 0.3 0.2 0.2 0.1 0.1 0.1 0 0 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 GAIN ERROR (%) 0.4 0 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 GAIN ERROR (%) 0.4 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 GAIN ERROR (%) 0.3 _______________________________________________________________________________________ 0.4 7 MAX9918/MAX9919/MAX9920 Typical Operating Characteristics (VCC = 5V, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = 5V, TA = +25°C, unless otherwise noted.) GAIN ERROR (VRS+ = -2V, MAX9919N, AV = +90V/V) GAIN ERROR vs. VCM 0.5 1.6 1.2 0.4 TA = +25NC 0.4 GE (%) N (%) TA = +125NC 0.8 0.3 MAX9918 toc11 2.0 MAX9918 toc10 0.6 0 -0.4 0.2 -0.8 -1.2 0.1 -2.0 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 GAIN ERROR (%) 0.3 -20 -10 0 0.4 GAIN ERROR vs. VCC 0.15 LINEARITY (%) 0.2 0.20 VCM = -2V 0 TA = -40°C 0.10 0 TA = +125°C TA = +25°C -0.10 -0.2 -0.15 VCM = 14V -0.4 -0.20 -0.5 -0.25 4.5 4.7 4.9 5.1 VCC (V) 5.3 -30 5.5 -20 0.04 TA = +25°C TA = -40°C 0.02 0 -0.02 0.06 TA = +25°C 0.04 20 30 VCM = -2V VCC = 5V VREFIN = VGND TA = -40°C AV = 90V/V UNIDIRECTIONAL 0.02 0 -0.02 TA = +125°C -0.04 0.08 LINEARITY (%) 0.06 VCM = +14V VCC = 5V VREFIN = VCC/2 AV = 90V/V BIDIRECTIONAL 0.10 MAX9918 toc14 0.08 0 10 VSENSE (mV) LINEARITY vs. VSENSE LINEARITY vs. VSENSE 0.10 -10 MAX9918 toc15 -0.3 VCM = -2V VCC = 5V VREFIN = VCC/2 AV = 90V/V BIDIRECTIONAL 0.05 -0.05 -0.1 MAX9918 toc13 0.3 GAIN ERROR (%) 0.25 MAX9918 toc12 0.4 TA = +125°C -0.04 -0.06 -0.06 -0.08 -0.08 -0.10 -0.10 -30 -20 -10 0 VSENSE (mV) 8 10 20 30 40 50 60 70 80 VCM (V) LINEARITY vs. VSENSE 0.5 0.1 TA = -40NC MAX9918ASA VCC = 5V VREF = VGND -1.6 0 LINEARITY (%) MAX9918/MAX9919/MAX9920 -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers 10 20 30 0 10 20 30 40 50 VSENSE (mV) 60 70 80 _______________________________________________________________________________________ -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers MAX9918 toc16 TA = -40°C 0.15 0.10 TA = +25°C 0.05 0 -0.05 -0.15 TA = +125°C -0.20 -0.25 -100 -80 -60 -40 -20 0 20 40 VSENSE (mV) 0.02 0 -0.02 TA = +25°C -0.04 -0.06 -0.08 -0.10 -100 -80 -60 -40 -20 0 20 40 VSENSE (mV) -2V VCM: SOLID LINE 14V VCM: DASHED LINE MAX9918, VREFIN = 0V UNIDIRECTIONAL, GAIN = 90V/V -20 -10 0 60 80 100 10 20 30 40 50 60 70 80 VSENSE (mV) VOH/VOL vs. IOH MAX9918 toc20 350 -2V VCM: SOLID LINE 14V VCM: DASHED LINE VCM = +14V 300 VOH AND VOL (mV) VOUT - VREFIN (V) VOUT - VREFIN vs. VSENSE 3.0 2.5 2.0 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 -2.0 -2.5 -3.0 MAX9918 toc19 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 -0.5 -1.0 MAX9918 toc21 TA = +125°C VOUT - VREFIN (V) LINEARITY (%) TA = -40°C VCM = +14V VCC = 5V VREFIN = VCC/2 AV = 30V/V BIDIRECTIONAL MAX9918 toc18 0.08 60 80 100 VOUT - VREFIN vs. VSENSE LINEARITY vs. VSENSE 0.10 0.04 TA = -40°C TA = +125°C -0.10 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 VSENSE (mV) 0.06 VCM = -2V VCC = 5V VREFIN = VCC/2 AV = 30V/V BIDIRECTIONAL 0.20 LINEARITY (%) LINEARITY (%) VCM = +14V VCC = 5V VREFIN = VGND AV = 90V/V UNIDIRECTIONAL TA = +25°C 0.25 MAX9918 toc17 LINEARITY vs. VSENSE LINEARITY vs. VSENSE 0.20 0.18 0.16 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0 -0.02 -0.04 -0.06 -0.08 -0.10 250 VCC - VOH 200 150 100 MAX9918, VREFIN = VCC/2 BIDIRECTIONAL, GAIN = 90V/V VOL 50 0 10 -40 -30 -20 -10 0 VSENSE (mV) 20 30 40 0 1 2 3 4 5 6 IOH (mA) 7 8 9 10 _______________________________________________________________________________________ 9 MAX9918/MAX9919/MAX9920 Typical Operating Characteristics (continued) (VCC = 5V, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = 5V, TA = +25°C, unless otherwise noted.) ICC vs. VCC ICC (mA) 0.5 VCM = 14V 0.3 0.2 0 VSENSE = 0V 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5 VCC (V) TA = +25NC 20 20 GAIN (dB) 600 500 400 200 -20 100 -30 0 -10 GAIN (dB) 0 -10 -20 10 25 VCM (V) 40 55 VCM = -2V -90 FREQUENCY (MHz) -100 0.001 0.1 1 FREQUENCY (MHz) 10 0 -20 MAX9918 VCM = 14V VSENSE = 50mV -60 -80 -100 -80 10 0.01 -40 -70 MAX9920 VCM = 14V GAIN = 20V/V 1 -40 0.001 70 -40 -50 MAX9918 VCM = 14V GAIN = 90V/V PSRR vs. FREQUENCY MAX9918 VCM = 14V GAIN = 90V/V -60 -30 10 -5 GAIN vs. FREQUENCY 10 -30 0.1 0 -10 -20 0.01 10 300 10 -60 0.001 40 30 -20 MAX9918 toc28 30 -50 GAIN vs. FREQUENCY 700 80 10 20 30 40 50 60 70 80 VCM (V) 50 MAX9918 toc26 800 GAIN vs. FREQUENCY -40 -20 -10 0 0 40 MAX9918 toc24 -100 10 20 30 40 50 60 70 80 VCM (V) 900 IN+ - IN- = 50mV VCC = VSHDN = 0V VREFIN = 0V 60 MAX9918 VCC = 5V -80 1000 DIFFERENTIAL RIN (I) TA = +125NC 20 40 VCM (V) -20 -60 -20 -10 0 MAX9918 toc25 INPUT LEAKAGE CURRENT (FA) TA = -40NC 0 0 DIFFERENTIAL RIN vs. VCM TA = +25NC -20 20 -40 INPUT LEAKAGE CURRENT vs. VCM 20 15 10 5 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50 TA = -40NC MAX9918 toc27 0.1 40 MAX9918 toc29 0.4 60 PSRR (dB) ICC (mA) 0.6 80 MAX9918 toc30 VCM = -2V VSENSE = 0V (DASH) VSENSE + 50mV (SOLID) TA = +125NC 100 MAX9918 toc23 0.8 1.6 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 IBAIS (FA) MAX9918 toc22 0.9 0.7 IBIAS vs. VCM ICC vs.VCM 1.0 GAIN (dB) MAX9918/MAX9919/MAX9920 -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers -120 VCM = 14V 0.01 0.1 1 FREQUENCY (MHz) 10 100 -140 10 100 0.0001 0.001 0.01 0.1 1 FREQUENCY (kHz) ______________________________________________________________________________________ 1k 10k -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers SMALL-SIGNAL TRANSIENT (GAIN = 90V/V) SMALL-SIGNAL TRANSIENT (GAIN = 45V/V) MAX9918 toc32 MAX9918 toc31 5mV/div 50mV/div 5mV/div MAX9918, VCM = 14V VSENSE = 10mV TO 15mV 100mV/div MAX9918, VCM = 14V VSENSE = 10mV TO 15mV 10Fs/div 10Fs/div LARGE-SIGNAL TRANSIENT (GAIN = 45V/V) LARGE-SIGNAL TRANSIENT (GAIN = 90V/V) MAX9918 toc33 50mV/div 500mV/div MAX9918 toc34 50mV/div MAX9918, VCM = 14V VSENSE = 0V TO 50mV 1V/div MAX9918, VCM = 14V VSENSE = 0 TO 50mV 10Fs/div 10Fs/div OUTPUT RESPONSE TO COMMON-MODE TRANSIENT COMMON-MODE STEP RESPONSE MAX9918 toc35 MAX9918 toc36 MAX9918, VCM = 14V SSENSE = PS (50mV) 10V/div 1V/div VCM 50V/div 0 OUTPUT AC-COUPLED FULL SCALE AT THE INPUT 10Fs/div VOUT 100mV/div 4µs/div ______________________________________________________________________________________ 11 MAX9918/MAX9919/MAX9920 Typical Operating Characteristics (continued) (VCC = 5V, TA = +25°C, unless otherwise noted.) MAX9918/MAX9919/MAX9920 -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers Typical Operating Characteristics (continued) (VCC = 5V, TA = +25°C, unless otherwise noted.) POWER-UP TIME SHUTDOWN ON/OFF DELAY MAX9918 toc38 MAX9918 toc37 5V/div 5V/div 2V/div 1V/div MAX9918, VCM = 14V VSENSE = PS (50mV) MAX9918, VCM = 14V VSENSE = PS (50mV) 4Fs/div 4Fs/div OUTPUT OVERDRIVE RECOVERY (30V/V) OUTPUT OVERDRIVE RECOVERY (90V/V) MAX9918 toc39 MAX9918 toc40 MAX9918, VCM = 14V VSENSE = 2 x PS 200mV/div 50mV/div 2V/div 2V/div 4Fs/div 12 MAX9918, VCM = 14V VSENSE = 2 x PS 4Fs/div ______________________________________________________________________________________ -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers TOP VIEW + RS+ 1 RS- 2 SHDN 3 8 VCC MAX9918 MAX9919 MAX9920 7 REFIN 6 EP* GND 4 FB 5 OUT 8 SOIC-EP *EXPOSED PAD. CONNECT EP TO SOLID GROUND FOR PROPER THERMAL AND ELECTRICAL PERFORMANCE. Pin Description PIN NAME 1 RS+ Positive Current-Sensing Input. Power side connects to external sense resistor. FUNCTION 2 RS- Negative Current-Sensing Input. Load side connects to external sense resistor. 3 SHDN Active-High Shutdown Input. Connect to GND for normal operation. 4 GND Ground 5 OUT Current-Sense Output. VOUT is proportional to VSENSE. 6 FB 7 REFIN 8 VCC — EP Feedback Input. Connect FB to a resistive-divider network to set the gain for the MAX9918 and MAX9920. See the Adjustable Gain (MAX9918/MAX9920) section for more information. Leave FB unconnected for the MAX9919 for proper operation. Reference Input. Set REFIN to VCC/2 for bidirectional operation. Set REFIN to GND for unidirectional operation. 5V Supply Voltage Input. Bypass VCC to GND with 0.1μF capacitor. Exposed Pad. Connect to a large-area contiguous ground plane for improved power dissipation. Do not use as the only ground connection for the part. Detailed Description The MAX9918/MAX9919/MAX9920 are single-supply, high-accuracy uni-/bidirectional current-sense amplifiers with a high common-mode input range that extends from -20V to +75V. The MAX9918/MAX9919/MAX9920’s input stage utilizes a pair of level shifters allowing a wide common-mode operating range when measuring the voltage drop (VSENSE) across the current-sense resistor. The first level shifter accommodates the upper commonmode operating range from +2V to +75V. When the common-mode voltage falls below +2V, the second level shifter is used to accommodate negative voltages down to -20V. The level shifters translate VSENSE to an internal reference voltage where it is then amplified with an instrumentation amplifier. The instrumentation amplifier configuration provides high precision with input offset voltages of 400μV (max). Indirect feedback of the instrumentation amplifier allows the gain to be adjusted with an external resistive-divider network on the MAX9918/MAX9920. The MAX9919 is a fixed gain device available with laser-trimmed resistors for gains of 45V/V (MAX9919F) and 90V/V (MAX9919N). The MAX9918/MAX9919 operate with a full-scale sense voltage of 50mV. The input stage of the MAX9920 provides an attenuation factor of 4, enabling a full-scale sense voltage of 200mV. ______________________________________________________________________________________ 13 MAX9918/MAX9919/MAX9920 Pin Configuration MAX9918/MAX9919/MAX9920 -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers Uni-/Bidirectional Operation The MAX9918/MAX9919 operate in bidirectional mode by application of a low-source impedance reference voltage in the 0V to VCC - 1.9V range, (typically VCC/2), to REFIN. For the MAX9920, the reference voltage range is 0V to VCC - 2.4V (typically VCC/2). The output voltage V OUT relative to V REFIN is then proportional to the ±VSENSE voltage drop from RS+ to RS- (Figure 2). The MAX9918/MAX9919/MAX9920 support both unidirectional and bidirectional operation. The devices operate in unidirectional mode with VREFIN = VGND. The output is then referenced to ground and the output voltage VOUT is proportional to the positive voltage drop (VSENSE) from RS+ to RS- (Figure 1). VOUT G = 90V/V 3.6V IDISCHARGE RSENSE 2.7V RS+ RS- LOAD MAX9919N 5V TO ADC OUT SHDN DISCHARGE CURRENT 1.8V VCC REFIN 0.9V GND 0 10mV 20mV 20mV 30mV VSENSE Figure 1. Unidirectional Operation VOUT - VREFIN G = 90V/V 1.8V IDISCHARGE ICHARGE RSENSE DISCHARGE CURRENT 0.9V RS+ RS- LOAD MAX9919N 5V VCC OUT SHDN REFIN TO ADC 2.5V -20mV CHARGE CURRENT -10mV 0 10mV 20mV -0.9V GND -1.8V Figure 2. Bidirectional Operation 14 ______________________________________________________________________________________ VSENSE -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers Adjustable Gain (MAX9918/MAX9920) The MAX9918/MAX9920 feature externally adjustable gain set by a resistive-divider network circuit using resistors R1 and R2 (see the Functional Diagram). The gain frequency compensation is set for a minimum gain of 30V/V for the MAX9918 and 7.5V/V for the MAX9920. The gain G for the MAX9918/MAX9920 is given by the following equation: ⎛ R2 ⎞ G = ⎜1+ ⎟ (for MAX9918) ⎝ R1 ⎠ and Sense Resistor, RSENSE Choose RSENSE based on the following criteria: Accuracy: A high RSENSE value allows lower currents to be measured more accurately. This is because offsets become less significant when the sense voltage is larger. In the linear region (100mV < V OUT < V CC - 100mV), there are two components to accuracy: input offset voltage (VOS) and gain error (GE). Use the linear equation to calculate total error: VOUT = (G ± GE) x (VSENSE ± VOS) For best performance, select R SENSE to provide approximately 50mV (MAX9918/MAX9919) or 200mV (MAX9920) of sense voltage for the full-scale current in each application. Sense resistors of 5mΩ to 100mΩ are available with 1% accuracy or better. Efficiency and Power Dissipation ⎛ ⎛ R2 ⎞ ⎞ ⎜ ⎜⎝ 1 + R1 ⎟⎠ ⎟ G= ⎜ ⎟ (for MAX9920) 4 ⎜ ⎟ ⎜⎝ ⎟⎠ Applications Information Component Selection Ideally, the maximum load current develops the fullscale sense voltage across the current-sense resistor. Choose the gain needed to yield the maximum output voltage required for the application: VOUT = VSENSE x G where VSENSE is the full-scale sense voltage, 50mV for the MAX9918/MAX9919, or 200mV for the MAX9920 and G is the gain of the device. G is externally adjustable for the MAX9918/MAX9920. The MAX9919 has a fixed gain version of 45V/V (MAX9919F) or 90V/V (MAX9919N). In unidirectional applications (VREFIN = 0V), select the gain of the MAX9918/MAX9920 to utilize the full output range between GND and VCC. In bidirectional applications (VREFIN = VCC/2), select the gain to allow an output voltage range of ±VCC/2. VOUT must be at least 100mV from either rail to achieve the rated gain accuracy. At high current levels, the I2R losses in RSENSE can be significant. Take this into consideration when choosing the resistor value and its power dissipation (wattage) rating. Also, the sense resistor’s value might drift if it is allowed to heat up excessively. The precision VOS of the MAX9918/MAX9919/MAX9920 allows the use of small sense resistors to reduce power dissipation and reduce hot spots. Inductance: Keep inductance low if ISENSE has a large high-frequency component by using resistors with low inductance value. Power-Supply Bypassing and Grounding Bypass the MAX9918/MAX9919/MAX9920’s V CC to ground with a 0.1μF capacitor. Grounding these devices requires no special precautions; follow the same cautionary steps that apply to the rest of the system. High-current systems can experience large voltage drops across a ground plane, and this drop may add to or subtract from VOUT. Using a differential measurement between OUT and REFIN prevents this problem. For highest current-measurement accuracy, use a single-point star ground. Connect the exposed pad to a solid ground to ensure optimal thermal performance. ______________________________________________________________________________________ 15 MAX9918/MAX9919/MAX9920 Shutdown Mode Drive SHDN high to enter low-power shutdown mode. In shutdown mode, the MAX9918/MAX9919/MAX9920 draw 0.5μA (typ) of quiescent current. -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers MAX9918/MAX9919/MAX9920 Functional Diagram VCC MAX9919F OUT A R2 FB RS+ 50mV (typ) RSENSE RS- INPUT INPUT STAGE/ LEVEL SHIFTER R1 REFIN ILOAD FIXED GAIN G = 45V/V OR 90V/V SHDN GND VCC MAX9918 MAX9920 A OUT R2 MAX9918 50mV (typ) MAX9920 200mV (typ) FB RS+ RSENSE RS- INPUT INPUT STAGE/ LEVEL SHIFTER R1 REFIN ILOAD ADJUSTABLE GAIN SHDN GND GAIN IS SET BY EXTERNAL RESISTORS, R1 AND R2 G = [1+(R2/R1)] FOR MAX9918 G = [1+(R2/R1)]/4 FOR MAX9920 Chip Information PROCESS: BiCMOS 16 ______________________________________________________________________________________ -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 8 SOIC-EP S8E+14 21-0111 90-0151 8L, SOIC EXP. PAD.EPS PACKAGE TYPE ______________________________________________________________________________________ 17 MAX9918/MAX9919/MAX9920 Package Information For the latest package outline information and land patterns (footprints), go to www.maxim-ic.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. MAX9918/MAX9919/MAX9920 -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers Revision History REVISION NUMBER REVISION DATE 0 10/09 Initial release — 1 1/10 Updated Functional Diagram 16 2 12/10 Added automotive qualified part 1 3 6/11 Added MAX9920ASA/V+ to data sheet 1 4 7/11 Added automotive qualified parts for the MAX9919NASA/V+ and the MAX9920ASA/V+ 1 DESCRIPTION PAGES CHANGED 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. 18 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2011 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.