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LTC6102

LTC6102-1/LTC6102HV

6102fe

For more information www.linear.com/LTC6102

Typical applicaTion

FeaTures

applicaTions

DescripTion

Precision Zero Drift

Current Sense Ampliﬁer

The LT C

6102/LTC6102HV are versatile, high voltage, high-

side current sense ampliﬁers. Their high supply voltage

rating allows their use in many high side applications,

while the low drift and offset ensure accuracy across a

wide range of operating conditions. The LTC6102-1 is a

version of the LTC6102 that includes a low power disable

mode to conserve system standby power.

The LTC6102/LTC6102HV monitor current via the voltage

across an external sense resistor (shunt resistor). Internal

circuitry converts input voltage to output current, allowing

a small sense signal on a large common mode voltage to

be translated to a ground-referred signal. Low DC offset

allows the use of very low shunt resistor values and large

gain-setting resistors. As a result, power loss in the shunt

is reduced.

The wide operating supply and high accuracy make the

LTC6102 ideal for a large array of applications, from auto

motive, to industrial and power management. A maximum

input sense voltage of 2V allows a wide range of currents

and

voltages

to be monitored. Fast response makes the

LTC6102 the perfect choice for load current warnings and

shutoff protection control.

All versions of the LTC6102 are available in 8-lead MSOP

and 3mm × 3mm DFN packages.

Supply Range:

4V to 60V, 70V Maximum (LTC6102)

5V to 100V, 105V Maximum (LTC6102HV)

±10µV Input Offset Maximum

±50nV/°C Input Offset Drift Maximum

Fast Response: 1µs Step Response

Gain Conﬁgurable with Two Resistors

Low Input Bias Current: 3nA Maximum

PSRR 130dB Minimum

Output Currents up to 1mA

Operating Temperature Range: –40°C to 125°C

Disable Mode (LTC6102-1 Only): 1µA Maximum

Available in 8-Lead MSOP and 3mm × 3mm

DFN Packages

Current Shunt Measurement

Battery Monitoring

Remote Sensing

Load Protection

Motor Control

Automotive Controls

Dynamic Current

Measurement Range

10A Current Sense with 10mA Resolution and 100mW

Maximum Dissipation

TO µP

6102 TA01

LTC2433-1

OUT

4.99k

OUT

1µF

OUT

= • V

SENSE

= 249.5V

SENSE

OUT

*PROPER SHUNT SELECTION COULD ALLOW

MONITORING OF CURRENTS IN EXCESS OF 1000A

LTC6102

20Ω

SENSE

1mΩ

5V TO

105V

–

OUT

+IN

–

–INF

–INS

REG

0.1µF

–

DYNAMIC RANGE (dB)

MAXIMUM SENSE VOLTAGE (V)

0.0001

110

100

0.001 0.01 10.1

6102 TA01b

DYNAMIC RANGE RELATIVE

TO 10µV OFFSET VOLTAGE

SENSE

= 100mΩ

Max V

SENSE

= 1V

SENSE

= 10mΩ

Max V

SENSE

= 100µV

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

Summary of content (26 pages)

PAGE 1
LTC6102 LTC6102-1/LTC6102HV Precision Zero Drift Current Sense Amplifier Description Features n n n n n n n n n n n Supply Range: 4V to 60V, 70V Maximum (LTC6102) 5V to 100V, 105V Maximum (LTC6102HV) ±10µV Input Offset Maximum ±50nV/°C Input Offset Drift Maximum Fast Response: 1µs Step Response Gain Configurable with Two Resistors Low Input Bias Current: 3nA Maximum PSRR 130dB Minimum Output Currents up to 1mA Operating Temperature Range: –40°C to 125°C Disable Mode (LTC6102-1 Only): 1µA Maximum Availabl
PAGE 2
LTC6102 LTC6102-1/LTC6102HV Absolute Maximum Ratings (Note 1) Total Supply Voltage (V+ to V–): LTC6102/LTC6102-1..............................................70V LTC6102HV..........................................................105V Input Voltage Range –INF, –INS................................. (V+ – 4V to V+ + 0.3V) +IN............................................. (V+ – 20V to V+ + 1V) EN............................................. (V– – 0.3V to V– + 9V) Differential (–INS – +IN), 1 Second..............
PAGE 3
LTC6102 LTC6102-1/LTC6102HV order information LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE LTC6102HMS8#PBF LTC6102HMS8#TRPBF LTCKJ 8-Lead Plastic MSOP –40°C to 125°C LTC6102CMS8-1#PBF LTC6102CMS8-1#TRPBF LTDXZ 8-Lead Plastic MSOP 0°C to 70°C LTC6102IMS8-1#PBF LTC6102IMS8-1#TRPBF LTDXZ 8-Lead Plastic MSOP –40°C to 85°C LTC6102HMS8-1#PBF LTC6102HMS8-1#TRPBF LTDXZ 8-Lead Plastic MSOP –40°C to 125°C LTC6102HVCMS8#PBF LTC6102HVCMS8#TRPBF LTCVB 8-Lead Plastic MSOP 0
PAGE 4
LTC6102 LTC6102-1/LTC6102HV electrical characteristics (LTC6102, LTC6102-1) The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. RIN = 10Ω, ROUT = 10k, VSENSE+ = V+ (see Figure 1 for details), V+ = 12V, V– = 0V, VEN = 2.2V unless otherwise noted.
PAGE 5
LTC6102 LTC6102-1/LTC6102HV Electrical Characteristics (LTC6102, LTC6102-1) The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. RIN = 10Ω, ROUT = 10k, VSENSE+ = V+ (see Figure 1 for details), V+ = 12V, V– = 0V, VEN = 2.2V unless otherwise noted.
PAGE 6
LTC6102 LTC6102-1/LTC6102HV Electrical Characteristics (LTC6102HV) The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. RIN = 10Ω, ROUT = 10k, VSENSE+ = V+ (see Figure 1 for details), V+ = 12V, V– = 0V unless otherwise noted.
PAGE 7
LTC6102 LTC6102-1/LTC6102HV Typical Performance Characteristics Input VOS vs Temperature Input VOS vs Supply Voltage 15 10 10 VS = 4V 5 0 VS = 12V –5 5 0 –5 TA = –40°C TA = 0°C TA = 25°C TA = 70°C TA = 85°C TA = 125°C –15 0 –20 20 40 60 80 100 120 TEMPERATURE (°C) 6102 G01 0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 SUPPLY VOLTAGE (V) MAXIMUM VOUT (V) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 –40 6102 G04 VS = 100V VS = 12V VS = 6V VS = 5V –20 0 20 40 60 80 100 120 TEMPERATURE (°C) 6.
PAGE 8
LTC6102 LTC6102-1/LTC6102HV Typical Performance Characteristics LTC6102: Supply Current vs Supply Voltage LTC6102HV: Supply Current vs Supply Voltage 600 600 500 SUPPLY CURRENT (μA) 400 300 TA = 25°C 200 TA = 0°C TA = –40°C 100 0 TA = 70°C 500 TA = 125°C V+ – 10mV TA = 125°C 400 0.
PAGE 9
LTC6102 LTC6102-1/LTC6102HV Typical Performance Characteristics LTC6102-1: Supply Current vs Supply Voltage 600 GAIN = 10 SUPPLY CURRENT (µA) 100 18 VEN = 2V VSENSE = –0.
PAGE 10
LTC6102 LTC6102-1/LTC6102HV pin functions –INS (Pin 1): Amplifier Inverting Input. When tied to –INF, the internal sense amplifier will drive –INS to the same potential as +IN. –INF (Pin 2): Force Input. This pin carries the input current from RIN and must be tied to –INS near RIN. A resistor (RIN) tied from V+ to –INF sets the output current IOUT = VSENSE/RIN. VSENSE is the voltage across the external RSENSE. V– (Pin 3, LTC6102/LTC6102HV Only): Negative Supply.
PAGE 11
LTC6102 LTC6102-1/LTC6102HV block diagram VBATTERY + VSENSE RSENSE – ILOAD 0.1µF RIN –INF L O A D –INS V+ 10V 10V 5V 5V VREG – 5k +IN + OUT 5k IOUT VOUT = VSENSE • ROUT EN* V– *LTC6102-1 ONLY ROUT RIN V– 6102 BD VENABLE Figure 1. Block Diagram and Typical Connection 6102fe For more information www.linear.
PAGE 12
LTC6102 LTC6102-1/LTC6102HV Applications Information The LTC6102 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 –INS to have the same potential as +IN.
PAGE 13
LTC6102 LTC6102-1/LTC6102HV Applications Information a significant load on the power supply and create thermal design headaches. In addition, heating in the sense resistor can reduce its accuracy and reliability. In contrast, the large dynamic range of the LTC6102 allows the use of a much smaller sense resistor. The LTC6102 allows the minimum sense voltage to be reduced to less than 10µV.
PAGE 14
LTC6102 LTC6102-1/LTC6102HV Applications Information 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 (Note 1) 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 output current and power dissipation.
PAGE 15
LTC6102 LTC6102-1/LTC6102HV Applications Information Ideally, the circuit output is: VOUT = VSENSE • ROUT ;V = RSENSE • ISENSE RIN SENSE In this case, the only error is due to resistor mismatch, which provides an error in gain only. Output Error, EOUT, Due to the Amplifier DC Offset Voltage, VOS The DC offset voltage of the amplifier adds directly to the value of the sense voltage, VSENSE. This error is very small (3µV typ) and may be ignored for reasonable values of RIN. See Figure 4.
PAGE 16
LTC6102 LTC6102-1/LTC6102HV Applications Information of the amp. This form of clock feedthrough is independent of the magnitude of the input source resistance or the magnitude of the gain setting resistors. The LTC6102 has a residue clock feedthrough of less then 1µVRMS input referred at 10kHz. The second form of clock feedthrough is caused by the small amount of charge injection occurring during the sampling and holding of the amp’s input offset voltage.
PAGE 17
LTC6102 LTC6102-1/LTC6102HV Applications Information Output Filtering VBAT The output voltage, VOUT, is simply IOUT • ZOUT. This makes filtering straightforward. Any circuit may be used which generates the required ZOUT to get the desired filter response. For example, a capacitor in parallel with ROUT will give a low pass response. This will reduce unwanted noise from the output, and may also be useful as a charge reservoir to keep the output steady while driving a switching circuit such as a mux or ADC.
PAGE 18
LTC6102 LTC6102-1/LTC6102HV Applications Information the allowed output current. The gain is still controlled by ROUT/RIN, so either gain or attenuation may be applied to the input signal as it is translated to the output. Finally, the input may be a voltage source rather than a sense resistor, as shown in Figure 8.
PAGE 19
LTC6102 LTC6102-1/LTC6102HV Applications Information If the output current is very low and an input transient occurs, there may be a delay before the output voltage begins changing. This can be reduced by increasing the minimum output current, either by increasing RSENSE or decreasing RIN. The effect of increased output current is illustrated in the step response curves in the Typical Performance Characteristics section of this datasheet.
PAGE 20
LTC6102 LTC6102-1/LTC6102HV Applications Information input resistor RIN) to flow into the output resistor and/or the output limiting ESD structure in the LTC6102. This is a temporary condition which will cease when the LTC6102 amplifier settles into normal closed-loop operation. V+ RIN– RSENSE RIN+ +IN –INS + LOAD RBIAS 2.7M – –INF V– V+ EN VREG LTC6102-1 0.1µF OUT VOUT ROUT RIN+ = RIN– – RSENSE 6102 F11 Figure 11 pin. Figure 11 shows the LTC6102-1 with a 2.
PAGE 21
LTC6102 LTC6102-1/LTC6102HV Typical Applications Bidirectional Current Sense Circuit with Separate Charge/Discharge Output ICHARGE IDISCHARGE RSENSE CHARGER RIN C 100Ω +IN VBATT V– RIN D 100Ω RIN C 100Ω –INS –INF + – RIN D 100Ω –INS –INF V+ – + V+ VREG 0.1µF OUT LTC6102 +IN 0.1µF + ROUT C 4.99k + VOUT C VOUT D – – V– VREG OUT L O A D LTC6102 ROUT D 4.
PAGE 22
LTC6102 LTC6102-1/LTC6102HV Typical Applications 16-Bit Resolution Unidirectional Output into LTC2433 ADC + 4V TO 60V VSENSE +IN – L O A D ILOAD RIN 100Ω –INS –INF + – V– V+ VREG 0.1µF EN POWER ENABLE OUT VOUT LTC6102-1 4 IN+ 1 REF+ VCC LTC2433-1 ROUT 4.99k 1µF 5V 2 5 IN– ROUT VOUT = • VSENSE = 49.9VSENSE RIN 8 SDD TO µP 7 CC REF– GND 3 9 SCK FO 6 10 ADC FULL-SCALE = 2.
PAGE 23
LTC6102 LTC6102-1/LTC6102HV Typical Applications Input Overvoltage Protection V+ RIN– DZ 1k 3W RSENSE 1k +IN –INS + LOAD – V– –INF V+ 0.1µF VREG OUT LTC6102 ROUT DZ: CENTRAL SEMICONDUCTOR CMZ5931B 18V 1.5W ZENER DIODE 6102 TA07 Simple 500V Current Monitor DANGER! Lethal Potentials Present — Use Caution 500V + VSENSE RSENSE – ISENSE L O A D +IN V– –INS RIN 100Ω –INF + – DANGER!! HIGH VOLTAGE!! V+ VREG 0.
PAGE 24
LTC6102 LTC6102-1/LTC6102HV Package Description DD Package 8-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1698 Rev C) R = 0.125 TYP 5 0.40 ± 0.10 8 0.70 ±0.05 3.5 ±0.05 1.65 ±0.05 2.10 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ± 0.05 3.00 ±0.10 (4 SIDES) PIN 1 TOP MARK (NOTE 6) 4 0.25 ± 0.05 0.75 ±0.05 0.200 REF 0.50 BSC 2.38 ±0.05 1.65 ± 0.10 (2 SIDES) 1 (DD8) DFN 0509 REV C 0.50 BSC 2.38 ±0.10 BOTTOM VIEW—EXPOSED PAD 0.00 – 0.
PAGE 25
LTC6102 LTC6102-1/LTC6102HV Revision History (Revision history begins at Rev D) REV DATE DESCRIPTION PAGE NUMBER D 8/10 Updated graph 21 8 E 6/14 Web Links Added All Correction to Output Current Absolute Maximum Ratings, (–1mA, +10mA) instead of (+1mA, –10mA) 2 Correction to Supply Current at V+=60V. Specification does not apply over the full operating temperature range 4 6102fe Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
PAGE 26
LTC6102 LTC6102-1/LTC6102HV Typical Application Remote Current Sense with Simple Noise Filter V+ RSENSE TIE AS CLOSE TO RIN AS POSSIBLE RIN– +IN –INS – + LOAD fC = 1 2 • π • ROUT • COUT –INF V– V+ VREG OUT LTC6102 6102 TA09 0.