LTC6101BIS5#TRMPBF

LTC6101/LTC6101HV High Voltage, High-Side Current Sense Amplifier in SOT-23 DESCRIPTION FEATURES Supply Range: 5V to 100V, 105V Absolute Maximum (LTC6101HV) 4V to 60V, 70V Absolute Maximum (LTC6101) n Low Offset Voltage: 300μV Max n Fast Response: 1μs Response Time (0V to 2.5V on a 5V Output Step) n Gain Configurable with 2 Resistors n Low Input Bias Current: 170nA Max n PSRR: 118dB Min n Output Current: 1mA Max n Low Supply Current: 250μA, V­ = 12V S n Specified Temperature Range: –40°C to 125°C n Operating Temperature Range: –55°C to 125°C n Package Option for High Voltage Spacing n Low Profile (1mm) SOT-23 (ThinSOT™) Package The LTC®6101/LTC6101HV are versatile, high voltage, high side current sense amplifiers. Design flexibility is provided by the excellent device characteristics; 300μV Max offset and only 375μA (typical at 60V) of current consumption. The LTC6101 operates on supplies from 4V to 60V and LTC6101HV operates on supplies from 5V to 100V. n The LTC6101 monitors current via the voltage across an external sense resistor (shunt resistor). Internal circuitry converts input voltage to output current, allowing for a small sense signal on a high common mode voltage to be translated into a ground referenced signal. Low DC offset allows the use of a small shunt resistor and large gain-setting resistors. As a result, power loss in the shunt is reduced. The wide operating supply range and high accuracy make the LTC6101 ideal for a large array of applications from automotive to industrial and power management. A maximum input sense voltage of 500mV allows a wide range of currents to be monitored. The fast response makes the LTC6101 the perfect choice for load current warnings and shutoff protection control. With very low supply current, the LTC6101 is suitable for power sensitive applications. APPLICATIONS n n n n Current Shunt Measurement Battery Monitoring Remote Sensing Power Management All registered trademarks and trademarks are the property of their respective owners. The LTC6101 is available in 5-lead SOT-23 and 8-lead MSOP packages. TYPICAL APPLICATION 16-Bit Resolution Unidirectional Output into LTC2433 ADC ILOAD VSENSE – Step Response + RIN 100Ω +IN VSENSE– 5V TO 105V ΔVSENSE– = 100mV –IN L O A D + – V– 5.5V 5V V+ 5V LTC6101HV OUT VOUT VOUT IOUT = 100µA ROUT 4.99k LTC2433-1 TO µP 6101 TA01 VOUT = Document Feedback TA = 25°C V+ = 12V RIN = 100 ROUT = 5k VSENSE+ = V+ 1µF ROUT • VSENSE = 49.9VSENSE RIN 0.5V 0V IOUT = 0 500ns/DIV 6101 TA01b Rev I For more information www.analog.com 1 LTC6101/LTC6101HV ABSOLUTE MAXIMUM RATINGS (Note 1) Total Supply Voltage (V+ to V–) LTC6101................................................................ 70V LTC6101HV......................................................... 105V Minimum Input Voltage (–IN Pin)..................... (V+ – 4V) Maximum Output Voltage (Out Pin).............................9V Input Current........................................................ ±10mA Output Short-Circuit Duration (to V–)............... Indefinite Operating Temperature Range LTC6101C/LTC6101HVC........................– 40°C to 85°C LTC6101I/LTC6101HVI.......................... –40°C to 85°C LTC6101H/LTC6101HVH.................... –55°C to 125°C Specified Temperature Range (Note 2) LTC6101C/LTC6101HVC............................ 0°C to 70°C LTC6101I/LTC6101HVI.......................... –40°C to 85°C LTC6101H/LTC6101HVH.................... –40°C to 125°C Storage Temperature Range................... –65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C PIN CONFIGURATION VHV PINOUT –IN NC NC OUT 1 2 3 4 TOP VIEW TOP VIEW TOP VIEW 8 7 6 5 +IN V+ NC V– OUT 1 V– 2 –IN 3 MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 150°C, θJA = 300°C/ W ORDER INFORMATION 5 V+ 4 +IN S5 PACKAGE 5-LEAD PLASTIC TSOT-23 TJMAX = 150°C, θJA = 250°C/ W +IN 1 5 OUT –IN 2 V+ 3 4 V– S5 PACKAGE 5-LEAD PLASTIC TSOT-23 TJMAX = 150°C, JA = 250°C/W http://www.linear.com/product/LTC6101#orderinfo LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE LTC6101ACMS8#PBF LTC6101ACMS8#TRPBF LTBSB 8-Lead Plastic MSOP 0°C to 70°C LTC6101AIMS8#PBF LTC6101AIMS8#TRPBF LTBSB 8-Lead Plastic MSOP –40°C to 85°C LTC6101AHMS8#PBF LTC6101AHMS8#TRPBF LTBSB 8-Lead Plastic MSOP –40°C to 125°C LTC6101HVACMS8#PBF LTC6101HVACMS8#TRPBF LTBSX 8-Lead Plastic MSOP 0°C to 70°C LTC6101HVAIMS8#PBF LTC6101HVAIMS8#TRPBF LTBSX 8-Lead Plastic MSOP –40°C to 85°C LTC6101HVAHMS8#PBF LTC6101HVAHMS8#TRPBF LTBSX 8-Lead Plastic MSOP –40°C to 125°C Rev I 2 For more information www.analog.com LTC6101/LTC6101HV ORDER INFORMATION Lead Free Finish TAPE AND REEL (MINI) TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE LTC6101ACS5#TRMPBF LTC6101ACS5#TRPBF LTBND 5-Lead Plastic TSOT-23 0°C to 70°C LTC6101AIS5#TRMPBF LTC6101AIS5#TRPBF LTBND 5-Lead Plastic TSOT-23 –40°C to 85°C LTC6101AHS5#TRMPBF LTC6101AHS5#TRPBF LTBND 5-Lead Plastic TSOT-23 –40°C to 125°C LTC6101BCS5#TRMPBF LTC6101BCS5#TRPBF LTBND 5-Lead Plastic TSOT-23 0°C to 70°C LTC6101BIS5#TRMPBF LTC6101BIS5#TRPBF LTBND 5-Lead Plastic TSOT-23 –40°C to 85°C LTC6101BHS5#TRMPBF LTC6101BHS5#TRPBF LTBND 5-Lead Plastic TSOT-23 –40°C to 125°C LTC6101CCS5#TRMPBF LTC6101CCS5#TRPBF LTBND 5-Lead Plastic TSOT-23 0°C to 70°C LTC6101CIS5#TRMPBF LTC6101CIS5#TRPBF LTBND 5-Lead Plastic TSOT-23 –40°C to 85°C LTC6101CHS5#TRMPBF LTC6101CHS5#TRPBF LTBND 5-Lead Plastic TSOT-23 –40°C to 125°C LTC6101HVACS5#TRMPBF LTC6101HVACS5#TRPBF LTBSZ 5-Lead Plastic TSOT-23 0°C to 70°C LTC6101HVAIS5#TRMPBF LTC6101HVAIS5#TRPBF LTBSZ 5-Lead Plastic TSOT-23 –40°C to 85°C LTC6101HVAHS5#TRMPBF LTC6101HVAHS5#TRPBF LTBSZ 5-Lead Plastic TSOT-23 –40°C to 125°C LTC6101HVBCS5#TRMPBF LTC6101HVBCS5#TRPBF LTBSZ 5-Lead Plastic TSOT-23 0°C to 70°C LTC6101HVBIS5#TRMPBF LTC6101HVBIS5#TRPBF LTBSZ 5-Lead Plastic TSOT-23 –40°C to 85°C LTC6101HVBHS5#TRMPBF LTC6101HVBHS5#TRPBF LTBSZ 5-Lead Plastic TSOT-23 –40°C to 125°C LTC6101HVCCS5#TRMPBF LTC6101HVCCS5#TRPBF LTBSZ 5-Lead Plastic TSOT-23 0°C to 70°C LTC6101HVCIS5#TRMPBF LTC6101HVCIS5#TRPBF LTBSZ 5-Lead Plastic TSOT-23 –40°C to 85°C LTC6101HVCHS5#TRMPBF LTC6101HVCHS5#TRPBF LTBSZ 5-Lead Plastic TSOT-23 –40°C to 125°C LTC6101VHVACS5#TRMPBF LTC6101VHVACS5#TRPBF LTHHD 5-Lead Plastic TSOT-23 HV Pinout 0°C to 70°C LTC6101VHVAIS5#TRMPBF LTHHD 5-Lead Plastic TSOT-23 HV Pinout –40°C to 85°C LTC6101VHVAHS5#TRMPBF LTC6101VHVAHS5#TRPBF LTC6101VHVAIS5#TRPBF LTHHD 5-Lead Plastic TSOT-23 HV Pinout –40°C to 125°C LTC6101VHVBCS5#TRMPBF LTC6101VHVBCS5#TRPBF LTHHD 5-Lead Plastic TSOT-23 HV Pinout 0°C to 70°C LTC6101VHVBIS5#TRMPBF LTHHD 5-Lead Plastic TSOT-23 HV Pinout –40°C to 85°C LTC6101VHVBHS5#TRMPBF LTC6101VHVBHS5#TRPBF LTHHD 5-Lead Plastic TSOT-23 HV Pinout –40°C to 125°C LTC6101VHVCCS5#TRMPBF LTC6101VHVCCS5#TRPBF LTHHD 5-Lead Plastic TSOT-23 HV Pinout 0°C to 70°C LTC6101VHVCIS5#TRMPBF LTHHD 5-Lead Plastic TSOT-23 HV Pinout –40°C to 85°C LTC6101VHVBIS5#TRPBF LTC6101VHVCIS5#TRPBF LTC6101VHVCHS5#TRMPBF LTC6101VHVCHS5#TRPBF LTHHD 5-Lead Plastic TSOT-23 HV Pinout TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container. Consult ADI Marketing for parts specified with wider operating temperature ranges. Consult ADI Marketing for information on lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ –40°C to 125°C Rev I For more information www.analog.com 3 LTC6101/LTC6101HV ELECTRICAL CHARACTERISTICS (LTC6101) The ● denotes the specifications which apply over the full specified temperature range, otherwise specifications are at TA = 25°C, RIN = 100Ω, ROUT = 10k, VSENSE+ = V+ (see Figure 1 for details), 4V ≤ VS ≤ 60V unless otherwise noted. SYMBOL PARAMETER VS Supply Voltage Range VOS Input Offset Voltage CONDITIONS MIN ● VSENSE = 5mV, Gain = 100, LTC6101A VSENSE = 5mV, Gain = 100, LTC6101AC, LTC6101AI VSENSE = 5mV, Gain = 100, LTC6101AH VSENSE = 5mV, Gain = 100, LTC6101B VSENSE = 5mV, Gain = 100, LTC6101C TYP 4 MAX UNITS 60 V ±85 ±300 ±450 ±535 µV µV µV ±150 ±450 ±810 µV µV ±400 800 1200 µV µV ● ● ● ● ∆VOS/∆T Input Offset Voltage Drift VSENSE = 5mV, LTC6101A VSENSE = 5mV, LTC6101B VSENSE = 5mV, LTC6101C IB Input Bias Current RIN = 1M IOS Input Offset Current RIN = 1M ● VSENSE(MAX) Input Sense Voltage Full Scale VOS within Specification, RIN = 1k (Note 3) ● 500 PSRR Power Supply Rejection Ratio VS = 6V to 60V, VSENSE = 5mV, Gain = 100 118 115 140 ● dB dB 110 105 133 ● dB dB ● ● ● 8 3 1 ±1 ±3 ±5 ● ● ● 100 170 245 nA nA ±2 ±15 nA ● VS = 4V to 60V, VSENSE = 5mV, Gain = 100 VOUT Maximum Output Voltage 12V ≤ VS ≤ 60V, VSENSE = 88mV VS = 6V, VSENSE = 330mV, RIN = 1k, ROUT = 10k VS = 4V, VSENSE = 550mV, RIN = 1k, ROUT = 2k VOUT (0) Minimum Output Voltage VSENSE = 0V, Gain = 100, LTC6101A VSENSE = 0V, Gain = 100, LTC6101AC, LTC6101AI VSENSE = 0V, Gain = 100, LTC6101AH mV V V V 0 30 45 53.5 mV mV mV 0 45 81 mV mV 0 150 250 mV mV ● ● VSENSE = 0V, Gain = 100, LTC6101B ● VSENSE = 0V, Gain = 100, LTC6101C µV/°C µV/°C µV/°C ● IOUT Maximum Output Current 6V ≤ VS ≤ 60V, ROUT = 2k, VSENSE = 110mV, Gain = 20 VS = 4V, VSENSE = 550mV, Gain = 2, ROUT = 2k tr Input Step Response (to 2.5V on a 5V Output Step) ∆VSENSE = 100mV Transient, 6V ≤ VS ≤ 60V, Gain = 50 VS = 4V 1 1.5 µs µs BW Signal Bandwidth IOUT = 200μA, RIN = 100, ROUT = 5k IOUT = 1mA, RIN = 100, ROUT = 5k 140 200 kHz kHz IS Supply Current VS = 4V, IOUT = 0, RIN = 1M VS = 6V, IOUT = 0, RIN = 1M VS = 12V, IOUT = 0, RIN = 1M VS = 60V, IOUT = 0, RIN = 1M LTC6101AI, LTC6101AC, LTC6101BI, LTC6101BC, LTC6101CI, LTC6101CC LTC6101AH, LTC6101BH, LTC6101CH ● ● 1 0.5 mA mA 220 450 475 µA µA 240 475 525 µA µA 250 500 590 µA µA 375 640 µA 690 720 µA µA ● ● ● ● ● Rev I 4 For more information www.analog.com LTC6101/LTC6101HV ELECTRICAL CHARACTERISTICS (LTC6101HV) The ● denotes the specifications which apply over the full specified temperature range, otherwise specifications are at TA = 25°C, RIN = 100Ω, ROUT = 10k, VSENSE+ = V+ (see Figure 1 for details), 5V ≤ VS ≤ 100V unless otherwise noted. SYMBOL PARAMETER VS Supply Voltage Range VOS Input Offset Voltage CONDITIONS MIN ● VSENSE = 5mV, Gain = 100, LTC6101HVA VSENSE = 5mV, Gain = 100, LTC6101HVAC, LTC6101HVAI VSENSE = 5mV, Gain = 100, LTC6101HVAH VSENSE = 5mV, Gain = 100, LTC6101HVB VSENSE = 5mV, Gain = 100, LTC6101HVC TYP MAX UNITS 100 V ±85 ±300 ±450 ±535 µV µV µV ±150 ±450 ±810 µV µV ±400 800 1200 µV µV 5 ● ● ● ● ∆VOS/∆T Input Offset Voltage Drift VSENSE = 5mV, LTC6101HVA VSENSE = 5mV, LTC6101HVB VSENSE = 5mV, LTC6101HVC IB Input Bias Current RIN = 1M IOS Input Offset Current RIN = 1M ● VSENSE(MAX) Input Sense Voltage Full Scale VOS within Specification, RIN = 1k (Note 3) ● 500 PSRR Power Supply Rejection Ratio VS = 6V to 100V, VSENSE = 5mV, Gain = 100 118 115 140 ● dB dB 110 105 133 ● dB dB ● ● 8 3 ±1 ±3 ±5 ● ● ● 100 170 245 nA nA ±2 ±15 nA ● VS = 5V to 100V, VSENSE = 5mV, Gain = 100 VOUT Maximum Output Voltage 12V ≤ VS ≤ 100V, VSENSE = 88mV VS = 5V, VSENSE = 330mV, RIN = 1k, ROUT = 10k VOUT (0) Minimum Output Voltage VSENSE = 0V, Gain = 100, LTC6101HVA VSENSE = 0V, Gain = 100, LTC6101HVAC, LTC6101HVAI VSENSE = 0V, Gain = 100, LTC6101HVAH mV V V 0 30 45 53.5 mV mV mV 0 45 81 mV mV 0 150 250 mV mV ● ● VSENSE = 0V, Gain = 100, LTC6101HVB ● VSENSE = 0V, Gain = 100, LTC6101HVC µV/°C µV/°C µV/°C ● IOUT Maximum Output Current 5V ≤ VS ≤ 100V, ROUT = 2k, VSENSE = 110mV, Gain = 20 tr Input Step Response (to 2.5V on a 5V Output Step) ∆VSENSE = 100mV Transient, 6V ≤ VS ≤ 100V, Gain = 50 VS = 5V 1 1.5 µs µs BW Signal Bandwidth IOUT = 200μA, RIN = 100, ROUT = 5k IOUT = 1mA, RIN = 100, ROUT = 5k 140 200 kHz kHz IS Supply Current VS = 5V, IOUT = 0, RIN = 1M VS = 6V, IOUT = 0, RIN = 1M VS = 12V, IOUT = 0, RIN = 1M VS = 60V, IOUT = 0, RIN = 1M LTC6101HVI, LTC6101HVC LTC6101HVH VS = 100V, IOUT = 0, RIN = 1M LTC6101HVAI, LTC6101HVAC, LTC6101HVBI, LTC6101HVBC, LTC6101HVCI, LTC6101HVCC LTC6101HVAH, LTC6101HVBH, LTC6101HVCH ● 1 mA 200 450 475 µA µA 220 475 525 µA µA 230 500 590 µA µA 350 640 690 720 µA µA µA 350 640 µA 690 720 µA µA ● ● ● ● ● ● ● Rev I For more information www.analog.com 5 LTC6101/LTC6101HV ELECTRICAL CHARACTERISTICS Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTC6101C/LTC6101HVC are guaranteed to meet specified performance from 0°C to 70°C. The LTC6101C/LTC6101HVC are designed, characterized and expected to meet specified performance from –40°C to 85°C but are not tested or QA sampled at these temperatures. LTC6101I/ LTC6101HVI are guaranteed to meet specified performance from –40°C to 85°C. The LTC6101H/LTC6101HVH are guaranteed to meet specified performance from –40°C to 125°C. Note 3: ROUT = 10k for 6V ≤ VS ≤ 100V, ROUT = 2k for VS = 4V. TYPICAL PERFORMANCE CHARACTERISTICS 600 20 INPUT OFFSET (µV) INPUT OFFSET (µV) 200 0 –200 –400 –600 A GRADE B GRADE C GRADE –800 –40 –20 0 RIN = 100 ROUT = 5k VIN = 5mV –40 TA = 25°C –60 –80 –100 TA = 85°C RIN = 100 ROUT = 5k VIN = 5mV –120 4 11 12 18 25 32 39 VSUPPLY (V) 46 60 VS = 4V 2 0 –40 –20 20 40 60 80 TEMPERATURE (°C) 100 120 LTC6101 LTC6101HV RIN = 3k ROUT = 3k 4 10 20 30 40 50 60 70 80 90 100 VSUPPLY (V) LTC6101: IOUT Maximum vs Temperature 7 6 VS = 12V 8 6 VS = 6V 4 VS = 4V VS = 5V 2 0 TA = 125°C 6101 G05 MAXIMUM IOUT (mA) 10 MAXIMUM OUTPUT (V) MAXIMUM OUTPUT (V) 4 53 0 VS = 100V VS = 6V TA = 85°C 1 0.5 12 VS = 60V 6 TA = 70°C LTC6101HV: VOUT Maximum vs Temperature VS = 12V TA = –40°C 6101 G02 LTC6101: VOUT Maximum vs Temperature 8 TA = 0°C 1.5 TA = 125°C –140 20 40 60 80 100 120 TEMPERATURE (°C) TA = 25°C 2 TA = –40°C –20 6101 G01 10 Input Sense Range 2.5 TA = 0°C 0 400 –1000 Input VOS vs Supply Voltage 40 REPRESENTATIVE UNITS MAXIMUM VSENSE (V) Input VOS vs Temperature 800 0 –40 –20 5 20 40 60 80 TEMPERATURE (°C) 100 120 6101 G06 6101 G20 VS = 60V 4 3 VS = 6V 2 1 0 VS = 12V VS = 4V 0 –40 –20 0 20 40 60 80 TEMPERATURE (°C) 100 120 6101 G07 Rev I 6 For more information www.analog.com LTC6101/LTC6101HV TYPICAL PERFORMANCE CHARACTERISTICS LTC6101HV: IOUT Maximum vs Temperature Output Error Due to Input Offset vs Input Voltage 100 7 2 1 VS = 100V VS = 6V VS = 5V 25 1 0.1 B GRADE VS = 4V 0 20 40 60 80 TEMPERATURE (°C) 0.01 100 120 120 VS = 6V TO 100V IB (nA) 100 80 VS = 4V 60 40 20 0 –40 –20 125°C 350 85°C 25°C 0°C –40°C 100 20 40 60 80 TEMPERATURE (°C) 100 120 0 0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 SUPPLY VOLTAGE (V) 70°C –40°C 0°C 125°C 300 25°C 200 0 VIN = 0 RIN = 1M 0 10 20 30 40 50 60 70 80 90 100 SUPPLY VOLTAGE (V) 6101 G11 Step Response 0mV to 10mV 6101 G22 Step Response 10mV to 20mV – VSENSE V+-10mV VSENSE– + V -20mV + 0.5V TA = 25°C V+ = 12V RIN = 100 ROUT = 5k VSENSE+ = V+ 0V 400 85°C 100 VIN = 0 RIN = 1M 6101 G10 V+ V -10mV 1M LTC6101HV: Supply Current vs Supply Voltage 500 250 150 10k 100k FREQUENCY (Hz) 600 300 200 1k 6101 G09 6101 G08 70°C 50 0 –10 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 INPUT VOLTAGE (V) SUPPLY CURRENT (µA) 140 400 SUPPLY CURRENT (µA) 450 IOUT = 200µA 10 0 LTC6101: Supply Current vs Supply Voltage 160 15 –5 6101 G21 Input Bias Current vs Temperature 20 5 C GRADE A GRADE 0 –40 –20 IOUT = 1mA TA = 25°C RIN = 100 ROUT = 4.99k 30 GAIN (dB) 3 35 10 5 4 TA = 25°C GAIN =10 VS = 12V OUTPUT ERROR (%) MAXIMUM IOUT (mA) 6 Gain vs Frequency 40 1V 0.5V VOUT TIME (10µs/DIV) TA = 25°C V+ = 12V RIN = 100 ROUT = 5k VSENSE+ = V+ VOUT TIME (10µs/DIV) 6101 G12 6101 G13 Rev I For more information www.analog.com 7 LTC6101/LTC6101HV TYPICAL PERFORMANCE CHARACTERISTICS Step Response 100mV V+ V+-100mV 5V Step Response Rising Edge Step Response 100mV VSENSE– V+ V+-100mV CLOAD = 10pF VSENSE– TA = 25°C V+ = 12V CLOAD = 2200pF RIN = 100 ROUT = 5k VSENSE+ = V+ 5V TA = 25°C V+ = 12V RIN = 100 ROUT = 5k VSENSE+ = V+ CLOAD = 1000pF VSENSE– ΔVSENSE– =100mV 5.5V 5V TA = 25°C V+ = 12V RIN = 100 ROUT = 5k VSENSE+ = V+ VOUT IOUT = 100µA 0V 0V VOUT 0.5V 0V VOUT TIME (100µs/DIV) TIME (10µs/DIV) IOUT = 0 TIME (500ns/DIV) 6101 G15 6101 G14 Step Response Falling Edge 6101 G16 PSRR vs Frequency 160 140 ΔVSENSE– =100mV 120 VOUT TA = 25°C V+ = 12V RIN = 100 ROUT = 5k VSENSE+ = V+ IOUT = 100µ 0.5V 0V IOUT = 0 TIME (500ns/DIV) PSRR (dB) 5.5V 5V LTC6101, V+ = 4V 100 80 LTC6101, LTC6101HV, V+ = 12V 60 R = 100 IN ROUT = 10k 40 C OUT = 5pF GAIN = 100 LTC6101HV, 20 I V+ = 5V OUTDC = 100µA VINAC = 50mVp 0 0.1 1 10 100 1k 10k 100k FREQUENCY (Hz) 6101 G17 1M 6101 G19 Rev I 8 For more information www.analog.com LTC6101/LTC6101HV PIN FUNCTIONS V+: Positive Supply Pin. Supply current is drawn through this pin. The circuit may be configured so that the LTC6101 supply current is or is not monitored along with the system load current. To monitor only system load current, connect V+ to the more positive side of the sense resistor. To monitor the total current, including the LTC6101 current, connect V+ to the more negative side of the sense resistor. OUT: Current Output. OUT will source a current that is proportional to the sense voltage into an external resistor. V – : Negative Supply (or Ground for Single-Supply Operation). –IN: The internal sense amplifier will drive IN– to the same potential as IN+. A resistor (RIN) tied from V+ to IN– sets the output current IOUT = VSENSE/RIN. VSENSE is the voltage developed across the external RSENSE (Figure 1). +IN: Must be tied to the system load end of the sense resistor, either directly or through a resistor. BLOCK DIAGRAM ILOAD – VSENSE RSENSE + V+ RIN VBATTERY 10V L O A D –IN 5k – +IN 5k + 10V LTC6101/LTC6101HV OUT V– 6101 BD IOUT VOUT = VSENSE x ROUT RIN ROUT Figure 1. LTC6101/LTC6101HV Block Diagram and Typical Connection APPLICATIONS INFORMATION The LTC6101 high side current sense amplifier (Figure 1) provides accurate monitoring of current through a userselected sense resistor. The sense voltage is amplified by a user-selected gain and level shifted from the positive power supply to a ground-referred output. The output signal is analog and may be used as is or processed with an output filter. Theory of Operation An internal sense amplifier loop forces IN– to have the same potential as IN+. Connecting an external resis- tor, RIN, between IN– and V+ forces a potential across RIN that is the same as the sense voltage across RSENSE. A corresponding current, V SENSE/RIN, will flow through RIN. The high impedance inputs of the sense amplifier will not conduct this input current, so it will flow through an internal MOSFET to the output pin. The output current can be transformed into a voltage by adding a resistor from OUT to V –. The output voltage is then VO = V– + IOUT • ROUT. Rev I For more information www.analog.com 9 LTC6101/LTC6101HV APPLICATIONS INFORMATION Useful Gain Configurations Gain RIN ROUT VSENSE at VOUT = 5V IOUT at VOUT = 5V 20 499 10k 250mV 500µA 50 200 10k 100mV 500µA 100 100 10k 50mV 500µA Selection of External Current Sense Resistor The external sense resistor, RSENSE, has a significant effect on the function of a current sensing system and must be chosen with care. First, the power dissipation in the resistor should be considered. The system load current will cause both heat and voltage loss in RSENSE. As a result, the sense resistor should be as small as possible while still providing the input dynamic range required by the measurement. Note that input dynamic range is the difference between the maximum input signal and the minimum accurately reproduced signal, and is limited primarily by input DC offset of the internal amplifier of the LTC6101. In addition, RSENSE must be small enough that VSENSE does not exceed the maximum input voltage specified by the LTC6101, even under peak load conditions. As an example, an application may require that the maximum sense voltage be 100mV. If this application is expected to draw 2A at peak load, RSENSE should be no more than 50mΩ. Once the maximum RSENSE value is determined, the minimum sense resistor value will be set by the resolution or dynamic range required. The minimum signal that can be accurately represented by this sense amp is limited by the input offset. As an example, the LTC6101B has a typical input offset of 150µV. If the minimum current is 20mA, a sense resistor of 7.5mΩ will set VSENSE to 150µV. This is the same value as the input offset. A larger sense resistor will reduce the error due to offset by increasing the sense voltage for a given load current. Peak dissipation is 200mW. If a 5mΩ sense resistor is employed, then the effective current error is 30mA, while the peak sense voltage is reduced to 10mV at 2A, dissipating only 20mW. The low offset and corresponding large dynamic range of the LTC6101 make it more flexible than other solutions in this respect. The 150µV typical offset gives 60dB of dynamic range for a sense voltage that is limited to 150mV max, and over 70dB of dynamic range if the rated input maximum of 500mV is allowed. Sense Resistor Connection Kelvin connection of the IN– and IN+ inputs to the sense resistor should be used in all but the lowest power applications. Solder connections and PC board interconnections that carry high current can cause significant error in measurement due to their relatively large resistances. One 10mm x 10mm square trace of one-ounce copper is approximately 0.5mΩ. A 1mV error can be caused by as little as 2A flowing through this small interconnect. This will cause a 1% error in a 100mV signal. A 10A load current in the same interconnect will cause a 5% error for the same 100mV signal. By isolating the sense traces from the high-current paths, this error can be reduced by orders of magnitude. A sense resistor with integrated Kelvin sense terminals will give the best results. Figure 2 illustrates the recommended method. V+ RIN RSENSE +IN –IN + LOAD Choosing a 50mΩ RSENSE will maximize the dynamic range and provide a system that has 100mV across the sense resistor at peak load (2A), while input offset causes an error equivalent to only 3mA of load current. V– – V+ LTC6101 OUT VOUT ROUT 6101 F02 Figure 2. Kelvin Input Connection Preserves Accuracy Despite Large Load Current Rev I 10 For more information www.analog.com LTC6101/LTC6101HV APPLICATIONS INFORMATION Selection of External Input Resistor, RIN V+ The external input resistor, RIN, controls the transconductance of the current sense circuit. Since IOUT = VSENSE/RIN, transconductance gm = 1/RIN. For example, if RIN = 100, then IOUT = VSENSE /100 or IOUT = 1mA for VSENSE = 100mV. RSENSE LOAD RIN should be chosen to allow the required resolution while limiting the output current. At low supply voltage, IOUT may be as much as 1mA. By setting RIN such that the largest expected sense voltage gives IOUT = 1mA, then the maximum output dynamic range is available. Output dynamic range is limited by both the maximum allowed output current and the maximum allowed output voltage, as well as the minimum practical output signal. If less dynamic range is required, then RIN can be increased accordingly, reducing the max output current and power dissipation. If low sense currents must be resolved accurately in a system that has very wide dynamic range, a smaller RIN than the max current spec allows may be used if the max current is limited in another way, such as with a Schottky diode across RSENSE (Figure 3a). This will reduce the high current measurement accuracy by limiting the result, while increasing the low current measurement resolution. Figure 3a. Shunt Diode Limits Maximum Input Voltage to Allow Better Low Input Resolution Without Overranging This approach can be helpful in cases where occasional large burst currents may be ignored. It can also be used in a multirange configuration where a low current circuit is added to a high current circuit (Figure 3b). Note that a comparator (LTC1540) is used to select the range, and transistor M1 limits the voltage across RSENSE LO. Care should be taken when designing the board layout for RIN, especially for small RIN values. All trace and interconnect impedances will increase the effective RIN value, causing a gain error. In addition, internal device resistance will add approximately 0.2Ω to RIN. VLOGIC (3.3V TO 5V) CMPZ4697 7 10k 3 M1 Si4465 VIN RSENSE HI 10m ILOAD VOUT 301 RSENSE LO 100m +IN V– DSENSE 6101 F03a + – LTC6101 301 301 –IN +IN –IN V+ V– OUT + – 8 5 301 VIN 4 + – 40.2k 6 4.7k 1.74M 2 V+ LTC1540 1 619k OUT LTC6101 7.5k Q1 CMPT5551 HIGH RANGE INDICATOR (ILOAD > 1.2A) HIGH CURRENT RANGE OUT 250mV/A VLOGIC BAT54C R5 7.5k (VLOGIC +5V) ≤ VIN ≤ 60V LOW CURRENT RANGE OUT 2.5V/A 0 ≤ ILOAD ≤ 10A Figure 3b. Dual LTC6101s Allow High-Low Current Ranging For more information www.analog.com 6101 F03b Rev I 11 LTC6101/LTC6101HV APPLICATIONS INFORMATION Selection of External Output Resistor, ROUT The output resistor, ROUT, determines how the output current is converted to voltage. VOUT is simply IOUT • ROUT. In choosing an output resistor, the max output voltage must first be considered. If the circuit that is driven by the output does not limit the output voltage, then ROUT must be chosen such that the max output voltage does not exceed the LTC6101 max output voltage rating. If the following circuit is a buffer or ADC with limited input range, then ROUT must be chosen so that IOUT(MAX) • ROUT is less than the allowed maximum input range of this circuit. In addition, the output impedance is determined by ROUT. If the circuit to be driven has high enough input impedance, then almost any useful output impedance will be acceptable. However, if the driven circuit has relatively low input impedance, or draws spikes of current, such as an ADC might do, then a lower ROUT value may be required in order to preserve the accuracy of the output. As an example, if the input impedance of the driven circuit is 100 times ROUT, then the accuracy of VOUT will be reduced by 1% since: VOUT = IOUT • R OUT • RIN(DRIVEN) R OUT +RIN(DRIVEN) = IOUT • R OUT • 100 101 = 0.99 •IOUT • R OUT Output Error, EOUT, Due to the Amplifier DC Offset Voltage, VOS EOUT(VOS) = VOS • (ROUT/RIN) The DC offset voltage of the amplifier adds directly to the value of the sense voltage, VSENSE. This is the dominant error of the system and it limits the available dynamic range. The paragraph “Selection of External Current Sense Resistor” provides details. Output Error, EOUT, Due to the Bias Currents, IB(+) and IB(–) The bias current IB(+) flows into the positive input of the internal op amp. IB(–) flows into the negative input. EOUT(IBIAS) = ROUT((IB(+) • (RSENSE/RIN) – IB(–)) Since IB(+) ≈ IB(–) = IBIAS, if RSENSE