LT6107 High Temperature High Side Current Sense Amp in SOT-23 FEATURES DESCRIPTION n Fully Tested at –55°C (MP), –40°C (H), The LT®6107 is a versatile high side current sense ampli- 25°C and 150°C fier designed for operation over a wide temperature range. n Gain Configurable with Two Resistors Design flexibility is provided by the excellent device char- n Low Offset Voltage: 250µV Maximum acteristics: 250µV maximum offset and 40nA maximum n Output Current: 1mA Maximum input bias current. Gain for each device is set by two n Supply Range: 2.7V to 36V, 44V Absolute Maximum resistors and allows for accuracy better than 1%. n Low Input Bias Current: 40nA Maximum The LT6107 monitors current via the voltage across an n PSRR: 106dB Minimum external sense resistor (shunt resistor). Internal circuitry n Low Supply Current: 65µA Typical, V+ = 12V converts input voltage to output current, allowing for a n Low Profile (1mm) ThinSOTTM Package small sense signal on a high common mode voltage to be translated into a ground referenced signal. The low DC APPLICATIONS offset allows for monitoring very small sense voltages. As a result, a small valued shunt resistor can be used, which n Current Shunt Measurement minimizes the power loss in the shunt. n Battery Monitoring n Power Management The wide 2.7V to 44V input voltage range, high accuracy n Motor Control and wide operating temperature range make the LT6107 n Lamp Monitoring ideal for automotive, industrial and power management n Overcurrent and Fault Detection applications. The very low power supply current of the LT6107 also makes it suitable for low power and battery All registered trademarks and trademarks are the property of their respective owners. operated applications. For applications not requiring the wide temperature range, see the LT6106. TYPICAL APPLICATION 3V to 36V, 5A Current Sense with A = 10 Measurement Accuracy vs Load Current V 3V TO 36V 0.6 0.4 E) L 0.2 100Ω A C 0.02Ω L S 0 TYPICAL PART, TA = 25°C +IN –IN UL F F–0.2 LOAD V– + – V+ ACY (% O––00..46 R U C–0.8 5A FULL SCALE C A RSENSE = 0.02 –1.0 AV = 10 ROUT = 1k RIN = 100 V+ = 3V LT6107 OUT 2V0O0UmTV/A –1.2 0 1 2 3 4 5 1k LOAD CURRENT (A) 6107 TA01b 6107 TA01a 6107fc 1 For more information www.linear.com/LT6107

LT6107 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) Supply Voltage (V+ to V–) ..........................................44V TOP VIEW Input Voltage (+IN to V–) .............................................V+ OUT 1 5 V+ (–IN to V–) ............................................V+ V– 2 Input Current ........................................................–10mA –IN 3 4 +IN Output Short-Circuit Duration ..........................Indefinite Operating Temperature Range (Note 2) S5 PACKAGE 5-LEAD PLASTIC TSOT-23 LT6107H ............................................–40°C to 150°C TJMAX = 150°C, (cid:84)JA = 250°C/W LT6107MP..........................................–55°C to 150°C Specified Temperature Range (Note 2) LT6107H ............................................–40°C to 150°C LT6107MP..........................................–55°C to 150°C Storage Temperature Range ..................–65°C to 150°C Lead Temperature (Soldering, 10 sec) ...................300°C ORDER INFORMATION http://www.linear.com/product/LT6107#orderinfo Lead Free Finish TAPE AND REEL (MINI) TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT6107HS5#TRMPBF LT6107HS5#TRPBF LTDGZ 5-Lead Plastic TSOT-23 –40°C to 150°C LT6107MPS5#TRMPBF LT6107MPS5#TRPBF LTDGZ 5-Lead Plastic TSOT-23 –55°C to 150°C Lead Based Finish TAPE AND REEL (MINI) TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT6107MPS5#TRM LT6107MPS5#TR LTDGZ 5-Lead Plastic TSOT-23 –55°C to 150°C TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container. 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/. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full specified operating temperature range, otherwise specifications are at TA = 25°C. V+ = 12V, V+ = VSENSE+, RIN = 100Ω, ROUT = 10k, Gain = 100 unless otherwise noted. (Note 6) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V+ Supply Voltage Range l 2.7 36 V V Input Offset Voltage V = 5mV 150 250 µV OS SENSE l 400 µV ∆V /∆T Input Offset Voltage Drift V = 5mV l 1 µV/°C OS SENSE I Input Bias Current (+IN) V+ = 12V, 36V 40 nA B l 65 nA I Input Offset Current V+ = 12V, 36V 1 nA OS I Maximum Output Current (Note 3) l 1 mA OUT PSRR Power Supply Rejection Ratio V+ = 2.7V to 36V, V = 5mV l 106 dB SENSE V Input Sense Voltage Full Scale R = 500Ω (Notes 3, 7) l 0.5 V SENSE(MAX) IN A Error Gain Error (Note 4) V = 500mV, R = 500Ω, R = 10k, V+ = 12.5V l –0.65 –0.25 0 % V SENSE IN OUT V = 500mV, R = 500Ω, R = 10k, V+ = 36V l –0.45 –0.14 0.1 % SENSE IN OUT 6107fc 2 For more information www.linear.com/LT6107

LT6107 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full specified operating temperature range, otherwise specifications are at TA = 25°C. V+ = 12V, V+ = VSENSE+, RIN = 100Ω, ROUT = 10k, Gain = 100 unless otherwise noted. (Note 6) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Output Swing High V = 120mV 1.2 V OUT(HIGH) SENSE (Referred to V+) l 1.4 V Minimum Output Voltage V = 0mV, R = 100Ω, R = 10k 12 45 mV SENSE IN OUT (Note 5) l 85 mV V = 0mV, R = 500Ω, R = 10k, V+ = 12V, 36V 7 16 mV SENSE IN OUT l 40 mV BW Signal Bandwidth (–3dB) I = 1mA, R = 100Ω, R = 5k 200 kHz OUT IN OUT t Input Step Response (to 50% of ∆V = 100mV Step, R = 100Ω, R = 5k, 3.5 µs r SENSE IN OUT Output Step) Rising Edge I Supply Current V+ = 2.7V, I = 0µA, (V = –5mV) 60 85 µA S OUT SENSE l 120 V+ = 12V, I = 0µA, (V = –5mV) 65 95 µA OUT SENSE l 125 V+ = 36V, I = 0µA, (V = –5mV) 70 100 µA OUT SENSE l 135 Note 1: Stresses beyond those listed under Absolute Maximum Ratings Note 3: Guaranteed by the gain error test. may cause permanent damage to the device. Exposure to any Absolute Note 4: Gain error refers to the contribution of the LT6107 internal circuitry Maximum Rating condition for extended periods may affect device and does not include errors in the external gain setting resistors. reliability and lifetime. In addition to the Absolute Maximum Ratings, the Note 5: The LT6107 output is an open collector current source. The output current of the LT6107 must be limited to insure that the power minimum output voltage scales directly with the ratio R /10k. OUT dissipation in the LT6107 does not allow the die temperature to exceed 150°C. See the applications information section “Power Dissipation Note 6: VSENSE+ is the voltage at the high side of the sense resistor, R . See Figure 1. Considerations” for further information. SENSE Note 7: V is the maximum sense voltage for which the Electrical Note 2: Junction temperatures greater than 125°C will promote SENSE(MAX) Characteristics will apply. Higher voltages can affect performance but will accelerated aging. The LT6107 has demonstrated typical life beyond 1000 not damage the part provided that the output current of the LT6107 does hours at 150°C. LT6107H is guaranteed to meet specified performance not exceed the allowable power dissipation as described in Note 1. from –40°C to 150°C. LT6107MP is guaranteed to meet specified performance from –55°C to 150°C. TYPICAL PERFORMANCE CHARACTERISTICS Input Offset Voltage vs Input Offset Voltage vs V Distribution Supply Voltage Temperature OS PERCENT OF UNITS (%) 11110264846 VVRR10+SION 6EU= N8=T 1S U=1E2 N0 V1=0I0 TΩ5kSmV NGE IN INPUT OFFSET VOLTAGE (µV) ––––71451363224000000000000 VRRTYSIONPEU NI=TCS =1AE 0 L1=0 0 UΩ5kNmIVTS INPUT OFFSET VOLTAGE (µV)––1123465200000000000000000 RTVVRAYS+VION PE U== NI=T C1S1 =1AE20 0 LV01=0 0 UΩ5kNmIVTS 2 CHA ––5600 –300 0 –70 –400 –200 –120 –40 0 40 120 200 0 5 10 15 20 25 30 35 40 –55–35–15 5 25 45 65 85 105125145165 INPUT OFFSET VOLTAGE (µV) SUPPLY VOLTAGE (V) TEMPERATURE (°C) 6107 G23 6107 G02 6107 G03 6107fc 3 For more information www.linear.com/LT6107

LT6107 TYPICAL PERFORMANCE CHARACTERISTICS Power Supply Rejection Ratio Power Supply Rejection Ratio Gain Error vs Temperature vs Frequency vs Frequency 0.00 120 V+ = 12.5V 120 V+ = 12.5V –0.05 V+ = 36V O (dB)110100 ARVIN = = 2 1000Ω O (dB)110100 ARVIN = = 2 5000Ω –0.10 ATI 90 ROUT = 2k ATI 90 ROUT = 10k R R R (%)–0.15 V+ = 12V TION 8700 TION 8700 GAIN ERRO–––000...232005 V+V =+ =2 .57VV PPLY REJEC 465000 PPLY REJEC 465000 U U –0.35 R S 30 R S 30 VOUT = 1V WE 20 VOUT = 0.5V WE 20 VOUT = 2.5V –0.40 IROOUUTT = = 1 1mkA PO 10 VVOOUUTT == 12VV PO 10 VVOOUUTT == 51V0V –0.45 0 0 –60–40–20 0 20 40 60 80100120140160180 100 1k 10k 100k 1M 100 1k 10k 100k 1M TEMPERATURE (°C) FREQUENCY (Hz) FREQUENCY (Hz) 6107 G04 6107 G08 6107 G06 Gain Error Distribution Gain vs Frequency Gain vs Frequency 24 45 45 22 V+ = 12.5V 40 V+ = 12.5V 40 V+ = 12.5V %) 2108 VRR11SION,EU0 N=T7S 2=5E 0 U1=00N Ω5kI0T0SmV 332505 VOUT = 1V0OVUT = 2.5V ARRVION U= =T 1 =10 00100Ωk 332505 VOUT = 10V ARRVION U= =T 2 =50 0100Ωk NITS ( 1164 TA = 25°C B) 2105 B) 2105 VOUT = 2.5V NT OF U 1102 GAIN (d 1050 GAIN (d 1050 E C 8 –5 –5 R PE 6 –10 –10 –15 –15 4 –20 –20 2 –25 –25 0 –30 –30 –0.60 –0.48 –0.36 –0.24 –0.12 0 1k 10k 100k 1M 10M 1k 10k 100k 1M 10M GAIN ERROR (%) FREQUENCY (Hz) FREQUENCY (Hz) 6107 G24 6107 G09 6107 G14 Input Bias Current vs Supply Step Response 0mV to 10mV Step Response 10mV to 20mV Voltage (R = 100Ω) (R = 100Ω) IN IN 300 226800 VRSINE N=S 1E0 =0 Ω5mV 20mVSVE/DNSIVE 20mVSVE/DNSIVE 240 nA)220 URRENT (112680000 TTAA == ––5450°°CC 500mVV/ODUIVT S C140 TA = 25°C VOUT PUT BIA11802000 TTTAAA === 711025°50C°°CC 500mV/D0IVV 0V IN 4600 TA = 175°C AV = 100 5µs/DIV 6107 G10 AV = 100 5µs/DIV 6107 G11 200 VRVO+O UU=TT 1 ==2 V01V0k TO 1V VRVO+O UU=TT 1 ==2 V11V0k TO 2V 0 5 10 15 20 25 30 35 40 45 50 SUPPLY VOLTAGE (V) 6107 G05 6107fc 4 For more information www.linear.com/LT6107

LT6107 TYPICAL PERFORMANCE CHARACTERISTICS Step Response 0mV to 100mV Step Response 10mV to 100mV Step Response 50mV to 100mV (RIN = 100Ω) (RIN = 100Ω) (RIN = 500Ω) VSENSE VSENSE VSENSE 200mV/DIV 200mV/DIV 100mV/DIV VOUT 2VV/ODUIVT 500mVV/ODUIVT 2V/DIV 0V 0V 0V AV = 100 5µs/DIV 6107 G12 AV = 100 5µs/DIV 6107 G13 AV = 20 5µs/DIV 6107 G15 VOUT = 0V TO 10V VOUT = 1V TO 10V VOUT = 1V TO 2V RV+O U=T 1 =2 V10k RV+O U=T 1 =2 V10k RV+O U=T 1 =2 V10k Step Response 0mV to 50mV Step Response 50mV to 500mV Step Response 0mV to 500mV (R = 500Ω) (R = 500Ω) (R = 500Ω) IN IN IN VSENSE VSENSE VSENSE 100mV/DIV 1V/DIV 1V/DIV VOUT VOUT 2V/DIV 2V/DIV VOUT 500mV/DIV 0V 0V 0V AV = 20 5µs/DIV 6107 G16 AV = 20 5µs/DIV 6107 G17 AV = 20 5µs/DIV 6107 G18 VOUT = 0V TO 1V VOUT = 1V TO 10V VOUT = 0V TO 10V RV+O U=T 1 =2 V10k RV+O U=T 1 =2 V10k RV+O U=T 1 =2 V10k Output Voltage Swing vs Output Voltage vs Input Sense Output Voltage vs Input Sense Temperature Voltage (0mV ≤ V ≤ 10mV) Voltage (0mV ≤ V ≤ 10mV) SENSE SENSE 11.15 1100 220 V+ = 12V V+ = 12V V+ = 12V 11.10 AV = 100 1000 AV = 100 200 AV = 20 RIN = 100Ω 900 RIN = 100Ω 180 RIN = 500Ω E (V) 11.05 RVSOEUNTS =E 1=0 1k20mV 870000 ROUT = 10k 116400 ROUT = 10k T VOLTAG 1101..9050 (mV)OUT650000 (mV)OUT112000 U V V P 400 80 T U O 10.90 300 60 200 40 10.85 100 20 10.80 0 0 –60–40–20 0 20 40 60 80100120140160180 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 TEMPERATURE (°C) VSENSE (mV) VSENSE (mV) 6107 G07 6107 G19 6107 G20 6107fc 5 For more information www.linear.com/LT6107

LT6107 TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage vs Input Sense Output Voltage vs Input Sense Voltage (0mV ≤ V ≤ 200mV) Voltage (0mV ≤ V ≤ 1V) Supply Current vs Supply Voltage SENSE SENSE 12 12 120 V+ = 12V V+ = 12V AV = 100 AV = 20 10 RIN = 100Ω 10 RIN = 500Ω 100 ROUT = 10k ROUT = 10k A) 8 8 T (µ 80 N (V)UT 6 (V)UT 6 URRE 60 O O C V 4 V 4 SUPPLY 40 TTTAAA === ––254550°C°°CC TA = 70°C 2 2 20 TA = 125°C TA = 150°C TA = 175°C 0 0 0 0 20 40 60 80 100120140160 180200 0 100200 300400500600700800 9001000 0 5 10 15 20 25 30 35 40 45 VSENSE (mV) VSENSE (mV) SUPPLY VOLTAGE (V) 6107 G21 6107 G22 6107 G01 PIN FUNCTIONS OUT (Pin 1): Current Output. OUT will source a current V+ (Pin 5): Positive Supply Pin. The V+ pin should be con- that is proportional to the sense voltage into an external nected directly to either side of the sense resistor, R . SENSE resistor. Supply current is drawn through this pin. The circuit may be configured so that the LT6107 supply current is or V– (Pin 2): Normally Connected to Ground. is not monitored along with the system load current. To –IN (Pin 3): The internal sense amplifier will drive –IN to monitor only the system load current, connect V+ to the the same potential as +IN. A resistor (RIN) tied from V+ more positive side of the sense resistor. To monitor the to –IN sets the output current IOUT = VSENSE/RIN. VSENSE total current, including that of the LT6107, connect V+ to is the voltage developed across RSENSE. the more negative side of the sense resistor. +IN (Pin 4): Must be tied to the system load end of the sense resistor, either directly or through a resistor. BLOCK DIAGRAM ILOAD –VSENSE+ VBATTERY RSENSE 5 L RIN V+ O A D –IN 14k – 3 +IN 14k 4 + IOUT V– OUT 1 VOUT = VSENSE • RROIUNT 2 6107 F01 ROUT Figure 1. LT6107 Block Diagram and Typical Connection 6107fc 6 For more information www.linear.com/LT6107

LT6107 APPLICATIONS INFORMATION Introduction must be small enough that V does not exceed the SENSE maximum input voltage specified by the LT6107, even The LT6107 high side current sense amplifier (Figure 1) pro- under peak load conditions. As an example, an application vides accurate monitoring of current through a user-selected may require that the maximum sense voltage be 100mV. sense resistor. The sense voltage is amplified by a user- If this application is expected to draw 2A at peak load, selected gain and level shifted from the positive power sup- R should be no more than 50mΩ. ply to a ground-referred output. The output signal is analog SENSE and may be used as is, or processed with an output filter. Once the maximum R value is determined, the min- SENSE imum sense resistor value will be set by the resolution or Theory of Operation dynamic range required. The minimum signal that can be accurately represented by this sense amplifier is limited An internal sense amplifier loop forces –IN to have the by the input offset. As an example, the LT6107 has a typi- same potential as +IN. Connecting an external resistor, R , between –IN and V+ forces a potential across R cal input offset of 150µV. If the minimum current is 20mA, IN IN a sense resistor of 7.5mΩ will set V to 150µV. This that is the same as the sense voltage across R . A SENSE SENSE is the same value as the input offset. A larger sense resis- corresponding current, V /R , will flow through R . SENSE IN IN tor will reduce the error due to offset by increasing the The high impedance inputs of the sense amplifier will not sense voltage for a given load current. Choosing a 50mΩ conduct this current, so it will flow through an internal R will maximize the dynamic range and provide a PNP to the output pin as I . SENSE OUT system that has 100mV across the sense resistor at peak The output current can be transformed into a voltage by load (2A), while input offset causes an error equivalent adding a resistor from OUT to V–. The output voltage is to only 3mA of load current. Peak dissipation is 200mW. then V = V– + I • R . O OUT OUT If a 5mΩ sense resistor is employed, then the effective current error is 30mA, while the peak sense voltage is Table 1. Useful Gain Configurations reduced to 10mV at 2A, dissipating only 20mW. GAIN RIN ROUT VSENSE at VOUT = 5V IOUT at VOUT = 5V 20 499Ω 10k 250mV 500µA The low offset and corresponding large dynamic range 50 200Ω 10k 100mV 500µA of the LT6107 make it more flexible than other solutions 100 100Ω 10k 50mV 500µA in this respect. The 150µV typical offset gives 60dB GAIN R R V at V = 2.5V I at V = 2.5V IN OUT SENSE OUT OUT OUT of dynamic range for a sense voltage that is limited to 20 249Ω 5k 125mV 500µA 150mV maximum, and over 70dB of dynamic range if the 50 100Ω 5k 50mV 500µA 100 50Ω 5k 25mV 500µA rated input maximum of 0.5V is allowed. Selection of External Current Sense Resistor Sense Resistor Connection The external sense resistor, R , has a significant Kelvin connection of the –IN and +IN inputs to the sense SENSE effect on the function of a current sensing system and resistor should be used in all but the lowest power appli- must be chosen with care. cations. Solder connections and PC board interconnec- tions that carry high current can cause significant error First, the power dissipation in the resistor should be con- in measurement due to their relatively large resistances. sidered. The system load current will cause both heat and One 10mm × 10mm square trace of one-ounce copper voltage loss in R . As a result, the sense resistor SENSE is approximately 0.5mΩ. A 1mV error can be caused by should be as small as possible while still providing the as little as 2A flowing through this small interconnect. input dynamic range required by the measurement. Note This will cause a 1% error in a 100mV signal. A 10A load that input dynamic range is the difference between the current in the same interconnect will cause a 5% error maximum input signal and the minimum accurately mea- for the same 100mV signal. By isolating the sense traces sured signal, and is limited primarily by input DC offset of from the high current paths, this error can be reduced the internal amplifier of the LT6107. In addition, R SENSE 6107fc 7 For more information www.linear.com/LT6107

LT6107 APPLICATIONS INFORMATION by orders of magnitude. A sense resistor with integrated This approach can be helpful in cases where occasional Kelvin sense terminals will give the best results. Figure 2 bursts of high currents can be ignored. illustrates the recommended method. Care should be taken when designing the board layout for R , especially for small R values. All trace and inter- V+ IN IN connect resistances will increase the effective R value, IN causing a gain error. RIN RSENSE +IN –IN Selection of External Output Resistor, R + – OUT LOAD V– V+ The output resistor, ROUT, determines how the output cur- rent is converted to voltage. V is simply I • R . OUT OUT OUT In choosing an output resistor, the maximum output OUT LT6107 VOUT voltage must first be considered. If the following circuit ROUT is a buffer or ADC with limited input range, then R OUT 6107 F02 must be chosen so that I • R is less than the OUT(MAX) OUT Figure 2. Kelvin Input Connection Preserves Accuracy with allowed maximum input range of this circuit. Large Load Currents In addition, the output impedance is determined by R . If OUT the circuit to be driven has high enough input impedance, Selection of External Input Resistor, R IN then almost any useful output impedance will be accept- R should be chosen to allow the required resolution IN able. However, if the driven circuit has relatively low input while limiting the output current to 1mA. In addition, the impedance, or draws spikes of current such as an ADC maximum value for RIN is 500Ω. By setting RIN such that might do, then a lower ROUT value may be required in order the largest expected sense voltage gives IOUT = 1mA, then to preserve the accuracy of the output. As an example, if the maximum output dynamic range is available. Output the input impedance of the driven circuit is 100 times R , OUT dynamic range is limited by both the maximum allowed then the accuracy of V will be reduced by 1% since: OUT output current and the maximum allowed output voltage, R •R as well as the minimum practical output signal. If less OUT IN(DRIVEN) V (cid:32)I • OUT OUT dynamic range is required, then R can be increased R (cid:14)R IN OUT IN(DRIVEN) accordingly, reducing the maximum output current and 100 power dissipation. If low sense currents must be resolved (cid:32)IOUT •ROUT • (cid:32)0.99•IOUT •ROUT 101 accurately in a system that has a very wide dynamic range, a smaller R than the maximum current spec allows may IN Error Sources be used if the maximum current is limited in another way, such as with a Schottky diode across R (Figure 3). The current sense system uses an amplifier and resistors SENSE This will reduce the high current measurement accuracy to apply gain and level shift the result. The output is then by limiting the result, while increasing the low current dependent on the characteristics of the amplifier, such as measurement resolution. gain and input offset, as well as resistor matching. Ideally, the circuit output is: V+ R OUT V (cid:32) V • ; V (cid:32)R •I RSENSE DSENSE OUT SENSE R SENSE SENSE SENSE IN 6107 F03 LOAD In this case, the only error is due to resistor mismatch, which provides an error in gain only. However, offset Figure 3. Shunt Diode Limits Maximum Input Voltage to Allow Better Low Input Resolution Without Overranging voltage and bias current cause additional errors. 6107fc 8 For more information www.linear.com/LT6107

LT6107 APPLICATIONS INFORMATION Output Error Due to the Amplifier DC Offset V+ Voltage, V OS RIN– E (cid:32) V •ROUT RSENSE RIN+ +IN –IN OUT(VOS) OS R + – IN LOAD The DC offset voltage of the amplifier adds directly to the V– V+ value of the sense voltage, V . This is the dominant SENSE error of the system and it limits the low end of the dynamic OUT range. The paragraph “Selection of External Current Sense LT6107 VOUT ROUT Resistor” provides details. RIN+ = RIN– – RSENSE 6107 F04 Output Error Due to the Bias Currents, I + and I – Figure 4. Second Input R Minimizes Error Due to Input Bias Current B B The bias current IB+ flows into the positive input of the Minimum Output Voltage internal op amp. I – flows into the negative input. B The curves of the Output Voltage vs Input Sense Voltage (cid:167) R (cid:183) show the behavior of the LT6107 with low input sense E (cid:32)R (cid:168)I (cid:14) • SENSE –I –(cid:184) OUT(IBIAS) OUT(cid:168)(cid:168) B B (cid:184)(cid:184) voltages. When V = 0V, the output voltage will always R SENSE (cid:169) IN (cid:185) be slightly positive, the result of input offset voltages and Assuming I + (cid:35) I – = I , and R << R then: of a small amount of quiescent current (0.7µA to 1.2µA) B B BIAS SENSE IN flowing through the output device. The minimum output E (cid:35) –R • I OUT(IBIAS) OUT BIAS voltage in the Electrical Characteristics table include both It is convenient to refer the error to the input: these effects. E (cid:35) –R • I IN(IBIAS) IN BIAS Power Dissipation Considerations For instance if I is 60nA and R is 1k, the input referred BIAS IN The power dissipated by the LT6107 will cause a small error is 60µV. Note that in applications where R (cid:35) SENSE increase in the die temperature. This rise in junction tem- R , I + causes a voltage offset in R that cancels the IN B SENSE perature can be calculated if the output current and the error due to I – and E (cid:35) 0mV. In most applica- B OUT(IBIAS) supply current are known. tions, R << R , the bias current error can be similarly SENSE IN reduced if an external resistor R + = (R – R ) is The power dissipated in the LT6107 due to the output IN IN SENSE signal is: connected as shown in Figure 4. Under both conditions: E = ±R • I ; where I = I + – I – POUT = (V–IN – VOUT) • IOUT IN(IBIAS) IN OS OS B B Since V (cid:35) V+, P (cid:35) (V+ – V ) • I If the offset current, I , of the LT6107 amplifier is 6nA, –IN OUT OUT OUT OS the 60µV error above is reduced to 6µV. The power dissipated due to the quiescent supply current is: Adding RIN+ as described will maximize the dynamic PQ = IS • (V+ – V–) range of the circuit. For less sensitive designs, R + is IN The total power dissipated is the output dissipation plus not necessary. the quiescent dissipation: Output Error Due to Gain Error P = P + P TOTAL OUT Q The LT6107 exhibits a typical gain error of –0.25% at 1mA The junction temperature is given by: output current. The primary source of gain error is due to T = T + (cid:84) • P the finite gain to the PNP output transistor, which results J A JA TOTAL in a small percentage of the current in R not appearing in At the maximum operating supply voltage of 36V and the IN the output load R . maximum guaranteed output current of 1mA, the total OUT 6107fc 9 For more information www.linear.com/LT6107

LT6107 APPLICATIONS INFORMATION power dissipation is 41mW. This amount of power dis- normal operation, V should not exceed 500mV (see SENSE sipation will result in a 10°C rise in junction temperature V under Electrical Characteristics). This addi- SENSE(MAX) above the ambient temperature. tional constraint can be stated as V+ – (+IN) ≤ 500mV. Referring to Figure 5, feedback will force the voltages It is important to note that the LT6107 has been designed at the inputs –IN and +IN to be equal to (V – V ). to provide at least 1mA to the output when required, and S SENSE Connecting V+ to the load side of the shunt results in equal can deliver more depending on the conditions. Care must voltages at +IN, –IN and V+. Connecting V+ to the supply be taken to limit the maximum output current by proper choice of sense resistor and R – and, if input fault con- end of the shunt results in the voltages at +IN and –IN to IN ditions exist, external clamps. be VSENSE below V+. If the V+ pin is connected to the supply side of the shunt Output Filtering resistor, the supply current drawn by the LT6107 is not The output voltage, V , is simply I • Z . This included in the monitored current. If the V+ pin is con- OUT OUT OUT makes filtering straightforward. Any circuit may be used nected to the load side of the shunt resistor (Figure 5), which generates the required Z to get the desired filter the supply current drawn by the LT6107 is included in OUT response. For example, a capacitor in parallel with R the monitored current. It should be noted that in either OUT will give a lowpass response. This will reduce unwanted configuration, the output current of the LT6107 will not noise from the output, and may also be useful as a charge be monitored since it is drawn through the R resistor IN reservoir to keep the output steady while driving a switch- connected to the positive side of the shunt. Contact the ing circuit such as a MUX or ADC. This output capacitor factory for operation of the LT6107 with a V+ outside of in parallel with an output resistor will create a pole in the the recommended operating range. output response at: VS RIN 1 f–3dB (cid:32) RSENSE 2•(cid:83) •R •C +IN –IN OUT OUT + – LOAD V– V+ Useful Equations Input Voltage: V (cid:32)I •R SENSE SENSE SENSE OUT Voltage Gain: VOUT (cid:32) ROUT LT6107 ROUVTOUT V R SENSE IN 6107 F05 Current Gain: IOUT (cid:32) RSENSE Figure 5. LT6107 Supply Current Monitored with the Load I R SENSE IN Reverse Supply Protection I 1 Transconductance: OUT (cid:32) V R Some applications may be tested with reverse-polarity SENSE IN supplies due to an expectation of the type of fault during V R Transimpedance: OUT (cid:32)R • OUT operation. The LT6107 is not protected internally from SENSE I R SENSE IN external reversal of supply polarity. To prevent damage that may occur during this condition, a Schottky diode Power Supply Connection should be added in series with V– (Figure 6). This will For normal operation, the V+ pin should be connected to limit the reverse current through the LT6107. Note that either side of the sense resistor. Either connection will this diode will limit the low voltage performance of the meet the constraint that +IN ≤ V+ and –IN ≤ V+. During LT6107 by effectively reducing the supply voltage to the part by V . D 6107fc 10 For more information www.linear.com/LT6107

LT6107 APPLICATIONS INFORMATION In addition, if the output of the LT6107 is wired to a Response Time device that will effectively short it to high voltage (such The photos in the Typical Performance Characteristics as through an ESD protection clamp) during a reverse show the response of the LT6107 to a variety of input supply condition, the LT6107’s output should be con- conditions and values of R . The photos show that if the nected through a resistor or Schottky diode (Figure 7). IN output current is very low or zero and an input transient occurs, there will be an increased delay before the output Demo Board voltage begins changing while internal nodes are being Demo board DC1240 is available for evaluation of the charged. LT6107. RSENSE RSENSE +IN –IN R1010Ω +IN –IN R1010Ω VBATT L V– + – V+ L V– + – V+ O O A A D VBATT D R3 1k D1 OUT LT6107 OUT ADC LT6107 R2 R2 4.99k D1 4.99k 6107 F07 6107 F06 Figure 6. Schottky Diode Prevents Damage During Supply Reversal Figure 7. Additional Resistor R3 Protects Output During Supply Reversal 6107fc 11 For more information www.linear.com/LT6107

LT6107 PACKAGE DESCRIPTION Please refer to http://www.linear.com/product/LT6107#packaging for the most recent package drawings. S5 Package 5-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1635) 0.62 0.95 MAX REF 2.90 BSC (NOTE 4) 1.22 REF 3.85 MAX2.62 REF 1.4 MIN 2.80 BSC 1(.5N0O T–E 1 4.7)5 PIN ONE RECOMMENDED SOLDER PAD LAYOUT 0.95 BSC 0.30 – 0.45 TYP PER IPC CALCULATOR 5 PLCS (NOTE 3) 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 1.90 BSC NOTE: (NOTE 3) S5 TSOT-23 0302 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193 6107fc 12 For more information www.linear.com/LT6107

LT6107 REVISION HISTORY (Revision history begins at Rev C) REV DATE DESCRIPTION PAGE NUMBER C 02/18 Addition of H-Temperature Option for –40°C to 150°C Operation 1-3 Web links added All 6107fc Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog 13 Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No liceFnoser mis ogrraen tiendfo brym imatpiloicna twionw owr .olitnheearwr.icseo mun/dLeTr 6a1ny0 7patent or patent rights of Analog Devices.

LT6107 TYPICAL APPLICATION Simple 400V Current Monitor DANGER! Lethal Potentials Present — Use Caution ISENSE VSENSE 400V – + RSENSE RIN +IN –IN 100Ω L V– + – V+ DANGER!! O HIGH VOLTAGE!! A D OUT 12V LT6107 CMPZ12L M1 BAT46 VOUT M2 ROUT 2M M1 AND M2 ARE FQD3P50 4.99k ROUT VOUT = R I N • VSENSE = 49.9 VSENSE 6107 TA02 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1787 Precision Bidirectional, High Side Current Sense Amplifier 75µV V , 60V, 60µA Operation OS LT6100 Gain-Selectable High Side Current Sense Amplifier 4.1V to 48V, Pin-Selectable Gain: 10, 12.5, 20, 25, 40, 50V/V LTC®6101/LTC6101HV High Voltage, High Side, Precision Current Sense Amplifiers 4V to 60V/5V to 100V, Gain Configurable, SOT-23 LTC6102/LTC6102HV Zero Drift High Side Current Sense Amplifier 4V to 60V/5V to 100V Operation, 10µV Offset, 1µs Step Response, MSOP8/DFN LTC6103 Dual High Side, Precision Current Sense Amplifier 4V to 60V, Gain Configurable 8-Pin MSOP LTC6104 Bidirectional High Side, Precision Current Sense Amplifier 4V to 60V, Gain Configurable 8-Pin MSOP LT6105 Rail-to-Rail Input Precision High Side Current Sense Amplifier –0.3V to 44V Input Common Mode Range, 300µV Offset, 1% Gain Accuracy, Gain Configurable LT6106 Low Cost, High Side Precision Current Sense Amplifier 2.7V to 36V, Gain Configurable, SOT-23 6107fc 14 LT 0218 REV C • PRINTED IN USA www.linear.com/LT6107 For more information www.linear.com/LT6107 (cid:164)(cid:3)ANALOG DEVICES, INC. 2008