LT6106 36V Low Cost High Side Current Sense in a SOT-23 FEATURES DESCRIPTION n Gain Configurable with Two Resistors The LT®6106 is a versatile high side current sense ampli- n Low Offset Voltage: 250µV Maximum fier. Design flexibility is provided by the excellent device n Output Current: 1mA Maximum characteristics: 250µV maximum offset and 40nA maxi- n Supply Range: 2.7V to 36V, 44V Absolute Maximum mum input bias current. Gain for each device is set by two n Low Input Bias Current: 40nA Maximum resistors and allows for accuracy better than 1%. n PSRR: 106dB Minimum The LT6106 monitors current via the voltage across an n Low Supply Current: 65µA Typical, V+ = 12V external sense resistor (shunt resistor). Internal circuitry n Operating Temperature Range: –40°C to 125°C converts input voltage to output current, allowing for a n Low Profile (1mm) ThinSOT™ 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 LT6106 n Lamp Monitoring ideal for automotive, industrial and power management n Overcurrent and Fault Detection applications. The very low power supply current of the LT6106 also makes it suitable for low power and battery operated applications. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION 3V to 36V, 5A Current Sense with A = 10 Measurement Accuracy vs Load Current V 3V TO 36V 0.6 LIMIT OVER TEMPERATURE 0.4 E) L 0.2 100Ω CA 0.02Ω L S 0 TYPICAL PART AT TA = 25°C +IN –IN UL F F–0.2 LOAD V– + – V+ ACY (% O––00..46 LIMIT OVER TEMPERATURE R U C–0.8 AC 5A FULL SCALE RIN = 100Ω –1.0 RSENSE = 0.02Ω ROUT = 1k AV = 10 V+ = 3V LT6106 OUT 2V0O0UmTV/A –1.2 0 1 2 3 4 5 1k LOAD CURRENT (A) 6106 TA01b 6106 TA01a 6106fb 1 For more information www.linear.com/LT6106

LT6106 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 S5 PACKAGE Operating Temperature Range (Note 4) 5-LEAD PLASTIC TSOT-23 LT6106C/LT6106I .................................–40°C to 85°C TJMAX = 150°C, θJA = 250°C/W LT6106H ............................................–40°C to 125°C Specified Temperature Range (Note 4) LT6106C ..................................................0°C to 70°C LT6106I ................................................–40°C to 85°C LT6106H ............................................–40°C to 125°C Storage Temperature Range ..................–65°C to 150°C Lead Temperature (Soldering, 10 sec) ...................300°C ORDER INFORMATION (http://www.linear.com/product/LT6106#orderinfo) TAPE AND REEL (MINI) TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE LT6106CS5#TRMPBF LT6106CS5#TRPBF LTCWK 5-Lead Plastic TSOT-23 0°C to 70°C LT6106IS5#TRMPBF LT6106IS5#TRPBF LTCWK 5-Lead Plastic TSOT-23 –40°C to 85°C LT6106HS5#TRMPBF LT6106HS5#TRPBF LTCWK 5-Lead Plastic TSOT-23 –40°C to 125°C *Temperature grades are identified by a label on the shipping container. Consult LTC Marketing for parts specified with wider operating temperature ranges. Parts ending with PBF are RoHS and WEEE compliant. 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 350 µV ΔV /ΔT 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 2) 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 2, 7) l 0.5 V SENSE(MAX) IN A Error Gain Error (Note 3) 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 6106fb 2 For more information www.linear.com/LT6106

LT6106 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. 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 65 mV V = 0mV, R = 500Ω, R = 10k, V+ = 12V, 36V 7 16 mV SENSE IN OUT l 22 mV BW Signal Bandwidth (–3dB) I = 1mA, R = 100Ω, R = 5k 200 kHz OUT IN OUT t Input Step Response (to 50% of ΔV = 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 115 V+ = 12V, I = 0µA, (V = –5mV) 65 95 µA OUT SENSE l 120 V+ = 36V, I = 0µA, (V = –5mV) 70 100 µA OUT SENSE l 130 Note 1: Stresses beyond those listed under Absolute Maximum Ratings characterized and expected to meet specified performance from –40°C to may cause permanent damage to the device. Exposure to any Absolute 85°C but is not tested or QA sampled at these temperatures. The LT6106I Maximum Rating condition for extended periods may affect device is guaranteed to meet specified performance from –40°C to 85°C. The reliability and lifetime. In addition to the Absolute Maximum Ratings, the LT6106H is guaranteed to meet specified performance from –40°C to output current of the LT6106 must be limited to insure that the power 125°C. dissipation in the LT6106 does not allow the die temperature to exceed Note 5: The LT6106 output is an open collector current source. The 150°C. See the applications information section “Power Dissipation minimum output voltage scales directly with the ratio R /10k. OUT Considerations” for further information. Note 6: VSENSE+ is the voltage at the high side of the sense resistor, Note 2: Guaranteed by the gain error test. R . See Figure 1. SENSE Note 3: Gain error refers to the contribution of the LT6106 internal Note 7: V is the maximum sense voltage for which the Electrical SENSE (MAX) circuitry and does not include errors in the external gain setting resistors. Characteristics will apply. Higher voltages can affect performance but will Note 4: The LT6106C is guaranteed functional over the operating not damage the part provided that the output current of the LT6106 does temperature range of –40°C to 85°C. The LT6106C is designed, not exceed the allowable power dissipation as described in Note 1. 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)––2241130000000000000 RVVS+IN E= N= 1S 1E20 V=0 Ω5mV TARYVOP U=IT C1 =A0 L01 0UkNITS 2 HA –50 –300 C –60 0 –70 –400 –200 –120 –40 0 40 120 200 0 5 10 15 20 25 30 35 40 –55 –25 5 35 65 95 125 INPUT OFFSET VOLTAGE (µV) SUPPLY VOLTAGE (V) TEMPERATURE (°C) 6106 G23 6106 G02 6106 G03 6106fb 3 For more information www.linear.com/LT6106

LT6106 TYPICAL PERFORMANCE CHARACTERISTICS Power Supply Rejection Ratio Power Supply Rejection Ratio Gain Error vs Temperature vs Frequency vs Frequency 0 120 120 V+ = 12.5V V+ = 12.5V ––00..1005 V+ = 36V O (dB)110100 ARVIN = = 2 1000Ω O (dB)110100 ARVIN = = 2 5000Ω –0.15 V+ = 12V RATI 90 ROUT = 2k RATI 90 ROUT = 10k GAIN ERROR (%)–––––00000.....3243200055 VV++ = = 2 5.7VV PPLY REJECTION 4685700000 PPLY REJECTION 4685700000 U U –0.45 VOUT = 1V R S 30 R S 30 –0.50 IOUT = 1mA WE 20 VOUT = 0.5V WE 20 VOUT = 2.5V –0.55 RTYOPUITC =A L1 kUNIT PO 10 VVOOUUTT == 12VV PO 10 VVOOUUTT == 51V0V –0.60 0 0 –45 –25 –5 15 35 55 75 95 115 130 100 1k 10k 100k 1M 100 1k 10k 100k 1M TEMPERATURE (°C) FREQUENCY (Hz) FREQUENCY (Hz) 6106 G04 6106 G08 6106 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) 6106 G24 6106 G09 6106 G14 Input Bias Current vs Supply Step Response 0mV to 10mV Step Response 10mV to 20mV Voltage (R = 100Ω) (R = 100Ω) IN IN 20 VSENSE = 5mV 19 RIN = 100Ω VSENSE VSENSE 20mV/DIV 20mV/DIV 18 A) n T ( 17 RREN 16 500mVV/ODUIVT CU 15 BIAS 14 500mVV/ODUIVT PUT 13 TA = –40°C 0V 0V IN 12 TA = 25°C 11100 5 10 15 20 25 30 35 TTT4AAA0 === 78140525°°5CC°C50 VARVVO+O UU==TT 1 1 ==20 V001V0k TO 1V 5µs/DIV 6106 G10 VARVVO+O UU==TT 1 1 ==20 V101V0k TO 2V 5µs/DIV 6106 G11 SUPPLY VOLTAGE (V) 6106 G05 6106fb 4 For more information www.linear.com/LT6106

LT6106 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 6106 G12 AV = 100 5µs/DIV 6106 G13 AV = 20 5µs/DIV 6106 G15 VOUT = 0V TO 10V VOUT = 1V TO 10V VOUT = 1V TO 2V ROUT = 10k ROUT = 10k ROUT = 10k V+ = 12V V+ = 12V V+ = 12V 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 6106 G16 AV = 20 5µs/DIV 6106 G17 AV = 20 5µs/DIV 6106 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 11.10 1100 220 V+ = 12V V+ = 12V V+ = 12V AV = 100 1000 AV = 100 200 AV = 20 11.05 RIN = 100Ω 900 RIN = 100Ω 180 RIN = 500Ω E (V) 11.00 RVSOEUNTS =E 1=0 1k20mV 870000 ROUT = 10k 116400 ROUT = 10k AG V) V) LT m 600 m 120 T VO 10.95 (OUT500 (OUT100 U V V UTP 10.90 400 80 O 300 60 10.85 200 40 100 20 10.80 0 0 –50 –25 0 25 50 75 100 125 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) 6106 G07 6106 G19 6106 G20 6106fb 5 For more information www.linear.com/LT6106

LT6106 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 V+ = 12V 12 V+ = 12V 120 AV = 100 AV = 20 10 RIN = 100Ω 10 RIN = 500Ω 100 ROUT = 10k ROUT = 10k A) 8 8 T (µ 80 V (V)OUT 6 V (V)OUT 6 LY CURREN 60 4 4 PP 40 SU TTAA == –2450°C°C 2 2 20 TA = 70°C TA = 85°C TA = 125°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) 6106 G21 6106 G22 6106 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 LT6106 supply current is or is V– (Pin 2): Normally Connected to Ground. 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 LT6106, 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 (cid:127) RROIUNT 2 6106 F01 ROUT Figure 1. LT6106 Block Diagram and Typical Connection 6106fb 6 For more information www.linear.com/LT6106

LT6106 APPLICATIONS INFORMATION Introduction must be small enough that V does not exceed the SENSE maximum input voltage specified by the LT6106, even The LT6106 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 mini- SENSE mum 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 by An internal sense amplifier loop forces –IN to have the the input offset. As an example, the LT6106 has a typical same potential as +IN. Connecting an external resistor, R , between –IN and V+ forces a potential across R input offset of 150µV. If the minimum current is 20mA, a IN IN sense resistor of 7.5mΩ will set V to 150µV. This is that is the same as the sense voltage across R . A SENSE SENSE 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 to adding a resistor from OUT to V–. The output voltage is only 3mA of load current. Peak dissipation is 200mW. If a then V = V– + I • R . O OUT OUT 5mΩ sense resistor is employed, then the effective current error is 30mA, while the peak sense voltage is reduced to Table 1. Useful Gain Configurations 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 of 50 200Ω 10k 100mV 500µA the LT6106 make it more flexible than other solutions in 100 100Ω 10k 50mV 500µA this respect. The 150µV typical offset gives 60dB of dy- GAIN R R V at V = 2.5V I at V = 2.5V IN OUT SENSE OUT OUT OUT namic range for a sense voltage that is limited to 150mV 20 249Ω 5k 125mV 500µA maximum, and over 70dB of dynamic range if the rated 50 100Ω 5k 50mV 500µA 100 50Ω 5k 25mV 500µA input maximum of 0.5V is allowed. Selection of External Current Sense Resistor Sense Resistor Connection The external sense resistor, R , has a significant effect Kelvin connection of the –IN and +IN inputs to the sense SENSE on the function of a current sensing system and must be resistor should be used in all but the lowest power ap- chosen with care. plications. Solder connections and PC board interconnec- tions that carry high current can cause significant error First, the power dissipation in the resistor should be in measurement due to their relatively large resistances. considered. The system load current will cause both heat One 10mm × 10mm square trace of one-ounce copper and voltage loss in R . As a result, the sense resis- SENSE is approximately 0.5mΩ. A 1mV error can be caused by tor should be as small as possible while still providing as little as 2A flowing through this small interconnect. the input dynamic range required by the measurement. This will cause a 1% error in a 100mV signal. A 10A load Note that input dynamic range is the difference between current in the same interconnect will cause a 5% error the maximum input signal and the minimum accurately for the same 100mV signal. By isolating the sense traces measured signal, and is limited primarily by input DC offset from the high current paths, this error can be reduced of the internal amplifier of the LT6106. In addition, R SENSE 6106fb 7 For more information www.linear.com/LT6106

LT6106 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 volt- OUT LT6106 VOUT age must first be considered. If the following circuit is a ROUT buffer or ADC with limited input range, then R must be OUT 6106 F02 chosen so that I • R is less than the allowed OUT(MAX) OUT Figure 2. Kelvin Input Connection Preserves Accuracy with 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 might maximum value for RIN is 500Ω. By setting RIN such that do, then a lower ROUT value may be required in order to the largest expected sense voltage gives IOUT = 1mA, then preserve the accuracy of the output. As an example, if the the maximum output dynamic range is available. Output 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 (cid:127)R as well as the minimum practical output signal. If less OUT IN(DRIVEN) V =I (cid:127) OUT OUT dynamic range is required, then R can be increased R +R IN OUT IN(DRIVEN) accordingly, reducing the maximum output current and power dissipation. If low sense currents must be resolved 100 =I (cid:127)R (cid:127) =0.99(cid:127)I (cid:127)R OUT OUT OUT OUT accurately in a system that has a very wide dynamic range, 101 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 V =V (cid:127) OUT; V =R (cid:127)I OUT SENSE SENSE SENSE SENSE RSENSE DSENSE RIN 6106 F03 LOAD In this case, the only error is due to resistor mismatch, which provides an error in gain only. However, offset volt- Figure 3. Shunt Diode Limits Maximum Input Voltage to Allow Better Low Input Resolution Without Overranging age and bias current cause additional errors. 6106fb 8 For more information www.linear.com/LT6106

LT6106 APPLICATIONS INFORMATION Output Error Due to the Amplifier DC Offset V+ Voltage, V OS RIN– E =V (cid:127)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 LT6106 VOUT ROUT Resistor” provides details. RIN+ = RIN– – RSENSE 6106 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 I + flows into the positive input of the B Minimum Output Voltage internal op amp. I – flows into the negative input. B The curves of the Output Voltage vs Input Sense Voltage  R  show the behavior of the LT6106 with low input sense E =R I + (cid:127) SENSE –I – OUT(IBIAS) OUTB B  voltages. When V = 0V, the output voltage will always  R  SENSE IN be slightly positive, the result of input offset voltages and Assuming I + @ 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 @ –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 @ –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 LT6106 will cause a small error is 60µV. Note that in applications where R @ 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 @ 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 LT6106 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 = (VIN– – VOUT) • IOUT IN(IBIAS) IN OS OS B B Since V – @ V+, P @ (V+ – V ) • I If the offset current, I , of the LT6106 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 LT6106 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 + θ • P the finite gain to the PNP output transistor, which results in J A JA TOTAL a small percentage of the current in R not appearing in the At the maximum operating supply voltage of 36V and the IN output load R . maximum guaranteed output current of 1mA, the total OUT 6106fb 9 For more information www.linear.com/LT6106

LT6106 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 ad- SENSE(MAX) above the ambient temperature. ditional constraint can be stated as V+ – (+IN) ≤ 500mV. Referring to Figure 5, feedback will force the voltages at It is important to note that the LT6106 has been designed the inputs –IN and +IN to be equal to (V – V ). Con- to provide at least 1mA to the output when required, and S SENSE necting 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 condi- end of the shunt results in the voltages at +IN and –IN to IN tions 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 LT6106 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 LT6106 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 LT6106 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 LT6106 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 2(cid:127)π(cid:127)R (cid:127)C RSENSE OUT OUT +IN –IN + – Useful Equations LOAD V– V+ Input Voltage: V =I (cid:127)R SENSE SENSE SENSE Voltage Gain: VOUT =ROUT LT6106 OUT VOUT VSENSE RIN ROUT 6106 F05 I R Current Gain: OUT = SENSE I R Figure 5. LT6106 Supply Current Monitored with the Load SENSE IN I 1 Reverse Supply Protection Transconductance: OUT = 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 =R (cid:127) OUT operation. The LT6106 is not protected internally from SENSE I R external reversal of supply polarity. To prevent damage that SENSE IN may occur during this condition, a Schottky diode should Power Supply Connection be added in series with V– (Figure 6). This will limit the For normal operation, the V+ pin should be connected to reverse current through the LT6106. Note that this diode either side of the sense resistor. Either connection will will limit the low voltage performance of the LT6106 by meet the constraint that +IN ≤ V+ and –IN ≤ V+. During effectively reducing the supply voltage to the part by VD. 6106fb 10 For more information www.linear.com/LT6106

LT6106 APPLICATIONS INFORMATION In addition, if the output of the LT6106 is wired to a device Response Time that will effectively short it to high voltage (such as through The photos in the Typical Performance Characteristics show an ESD protection clamp) during a reverse supply condi- the response of the LT6106 to a variety of input conditions tion, the LT6106’s output should be connected through and values of R . The photos show that if the output a resistor or Schottky diode (Figure 7). IN current is very low or zero and an input transient occurs, there will be an increased delay before the output voltage Demo Board begins changing while internal nodes are being charged. Demo board DC1240 is available for evaluation of the LT6106. RSENSE RSENSE R1010Ω VBATT +IN –IN R1 +IN –IN 100Ω OL V– + – V+ A L V– + – V+ D R3 O 1k DA VBATT LT6106 OUT ADC R2 D1 OUT D1 4.99k LT6106 6106 F07 R2 4.99k 6106 F06 Figure 7. Additional Resistor R3 Protects Output During Supply Reversal Figure 6. Schottky Diode Prevents Damage During Supply Reversal 6106fb 11 For more information www.linear.com/LT6106

LT6106 PACKAGE DESCRIPTION Please refer to http://www.linear.com/product/LT6106#packaging for the most recent package drawings. S5 Package 5-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1635) 0.62 0.95 2.90 BSC MAX REF (NOTE 4) 1.22 REF 1.50 – 1.75 3.85 MAX 2.62 REF 1.4 MIN 2.80 BSC (NOTE 4) PIN ONE RECOMMENDED SOLDER PAD LAYOUT 0.30 – 0.45 TYP 0.95 BSC 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 6106fb 12 For more information www.linear.com/LT6106

LT6106 REVISION HISTORY (Revision history begins at Rev B) REV DATE DESCRIPTION PAGE NUMBER B 03/16 Reformat of Order Information. 2 Addition of industrial temp (I) version. 2, 3 Addition of Web links. All Reformat of Package Description information. 12 Related Parts list updated and appended. 14 6106fb Information furnished by Linear Technology Corporation is believed to be accurate and reliable. 13 However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconneFctoiorn m ofo itrse c iinrcfuoitrsm asa tdieosnc rwibwedw h.elrineiena wr.ilcl onomt i/nLfTrin6g1e0 o6n existing patent rights.

LT6106 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 LT6106 CMPZ12L M1 BAT46 VOUT M2 ROUT 2M M1 AND M2 ARE FQD3P50 4.99k ROUT VOUT = R I N (cid:127) VSENSE = 49.9 VSENSE 6106 TA02 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1787 Bidirectional High Side Current Sense Amplifier V : 2.7V to 60V, 75μV Offset, 8V/V Gain IN LTC4150 Coulomb Counter/Battery Gas Gauge Indicates Charge Quantity and Polarity LT6100 Gain-Selectable High Side Current Sense Amplifier V : 4.1V to 48V, Gain Settings: 10V, 12.5V, 20V, 25V, 40V, 50V/V IN LTC6101 High Voltage High Side Current Sense Amplifier V : 4V to 100V, Resistor-Set Gain, 300μV Offset, SOT-23 IN LTC6102 Zero-Drift High Side Current Sense Amplifier V : 4V to 100V, Resistor-Set Gain, 10μV Offset, MSOP8/DFN IN LTC6103 Dual High Side Current Sense Amplifier V : 4V to 60V, Resistor-Set Gain, Independent Amps, MSOP8 IN LTC6104 Bidirectional High Side Current Sense Amplifier V : 4V to 60V, Resistor-Set Gain Each Direction, MSOP8 IN LT6105 High Side or Low Side Current Sense Amplifier V : –0.3V to 44V, 300μV Offset, Resistor-Set Gain IN LT6107 High Temp High Side Current Sense Amplifier V : 2.7V to 36V, 250μV Offset, –55°C to 150°C IN LT6108 High Side Current Sense Amplifier, Reference and V : 2.7V to 60V, 125μV Offset, Resistor-Set Gain, ±1.25% Threshold Error IN Comparator with Shutdown LT6109 High Side Current Sense Amplifier, Reference and 2 V : 2.7V to 60V, 125μV Offset, Resistor-Set Gain, ±1.25% Threshold Error IN Comparators with Shutdown LT6118 High Side Current Sense Amplifier, Reference and V : 2.7V to 60V, 200μV Offset, Resistor-Set Gain, ±1.25% Threshold Error IN Comparator with Power-On Reset Capability LT6119 High Side Current Sense Amplifier, Reference and 2 V : 2.7V to 60V, 200μV Offset, Resistor-Set Gain, ±1.25% Threshold Error IN Comparators with Power-On Reset Capability 6106fb 14 Linear Technology Corporation LT 0316 REV B • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 For more information www.linear.com/LT6106 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LT6106  LINEAR TECHNOLOGY CORPORATION 2007

Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: A nalog Devices Inc.: LT6106IS5#TRMPBF LT6106HS5#TRPBF LT6106CS5 LT6106IS5#TRPBF LT6106HS5#PBF LT6106CS5#PBF LT6106CS5#TRPBF LT6106CS5#TR LT6106HS5 LT6106HS5#TRMPBF LT6106CS5#TRMPBF