LT6100
Precision, Gain Selectable
High Side Current Sense
Amplifier
DESCRIPTION
FEATURES
Input Offset Voltage: 300µV (Max)
n Sense Inputs Up to 48V
n 0.5% Gain Accuracy
n Pin Selectable Gain: 10, 12.5, 20, 25, 40, 50V/V
n Separate Power Supply: 2.7V to 36V
n Operating Current: 60µA
n Sense Input Current (V
CC Powered Down): 1nA
n Reverse Battery Protected to –48V
n Buffered Output
n Noise Filtering Input
n –40°C to 125°C Operating Temperature Range
n Available in 8-Lead DFN and MSOP Packages
The LT®6100 is a complete micropower, precision, high
side current sense amplifier. The LT6100 monitors unidirectional currents via the voltage across an external sense
resistor. Fixed gains of 10, 12.5, 20, 25, 40, 50V/V are
obtained by simply strapping or floating two gain select
pins. Gain accuracy is better than 0.5% for all gains.
n
The LT6100 sense inputs have a voltage range that extends
from 4.1V to 48V, and can withstand a differential voltage
of the full supply. This makes it possible to monitor the
voltage across a MOSFET switch or a fuse. The part can
also withstand a reverse battery condition on the inputs.
Input offset is a low 300µV. CMRR and PSRR are in excess of 105dB, resulting in a wide dynamic range. A filter
pin is provided to easily implement signal filtering with a
single capacitor.
APPLICATIONS
n
n
n
n
Battery Monitoring
Fuse Monitoring
Portable and Cellular Phones
Portable Test/Measurement Systems
L, LT, LTC, LTM, Linear Technology, the Linear logo and Over-The-Top are registered
trademarks of Linear Technology Corporation. All other trademarks are the property of their
respective owners.
The LT6100 has a separate supply input, which operates
from 2.7V to 36V and draws only 60µA. When VCC is
powered down, the sense pins are biased off. This prevents loading of the monitored circuit, irrespective of the
sense voltage. The LT6100 is available in an 8-lead DFN
and MSOP package.
TYPICAL APPLICATION
0A to 33A High Side Current Monitor with 12kHz Frequency Rolloff
3V
2
LT6100
VCC
1.5
7
6
A4
A2
+
8 VS
VOUT 5
RSENSE
3mΩ
–
1 VS
LOAD
CONFIGURED FOR GAIN = 25V/V
VEE
FIL
4
3
VOUT = 2.5V
ISENSE = 33A
INPUT OFFSET VOLTAGE (mV)
4.4V TO 48V
SUPPLY
Input Offset Voltage
vs VS Sense Input Voltage
6100 TA01a
1.0
0.5
0
–0.5
–1.0
–1.5
220pF
VSENSE = 100mV
VCC = 3V
TA = 25°C
0
5
10 15 20 25 30 35 40 45 50
VS SENSE INPUT VOLTAGE (V)
6100 TA01b
6100fd
For more information www.linear.com/LT6100
1
LT6100
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Differential Sense Voltage....................................... ±48V
Total VS+, VS – to VEE ................................................ 48V
Total VCC Supply Voltage from VEE .......................... 36V
Output Voltage................................ (VEE) to (VEE + 36V)
Output Short-Circuit Duration (Note 3)......... Continuous
Operating Temperature Range (Note 4)
LT6100C .............................................–40°C to 85°C
LT6100I ...............................................–40°C to 85°C
LT6100H ........................................... –40°C to 125°C
Specified Temperature Range (Note 5)
LT6100C ................................................. 0°C to 70°C
LT6100I ...............................................–40°C to 85°C
LT6100H ........................................... –40°C to 125°C
Storage Temperature Range............................................
DFN..................................................... –65°C to 125°C
MSOP................................................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
MSOP............................................................... 300°C
PACKAGE/ORDER INFORMATION
TOP VIEW
VS– 1
VCC 2
FIL 3
8
9
VEE 4
TOP VIEW
VS+
7
A4
6
A2
5
VOUT
VS–
VCC
FIL
VEE
1
2
3
4
8
7
6
5
VS+
A4
A2
VOUT
MS8 PACKAGE
8-LEAD PLASTIC MSOP
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
TJMAX = 150°C, θJA = 250°C/W
TJMAX = 125°C, θJA = 43°C/W
EXPOSED PAD (PIN 9) IS VEE, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
SPECIFIED TEMPERATURE RANGE
LT6100CDD#PBF
LT6100CDD#TRPBF
LBMW
8-Lead (3mm × 3mm) Plastic DFN
0°C to 70°C
LT6100IDD#PBF
LT6100IDD#TRPBF
LBMW
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 85°C
LT6100HDD#PBF
LT6100HDD#TRPBF
LBMW
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT6100CMS8#PBF
LT6100CMS8#TRPBF
LTBMV
8-Lead Plastic MS8
0°C to 70°C
LT6100IMS8#PBF
LT6100IMS8#TRPBF
LTBMV
8-Lead Plastic MS8
–40°C to 85°C
LT6100HMS8#PBF
LT6100HMS8#TRPBF
LTBMV
8-Lead Plastic MS8
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping
container.Consult LTC Marketing for information on nonstandard 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/
6100fd
2
For more information www.linear.com/LT6100
LT6100
ELECTRICAL CHARACTERISTICS
The l denotes specifications which apply over the temperature range 0°C ≤ TA ≤ 70°C (LT6100C), otherwise specifications are
TA = 25°C. VCC = 5V, VEE = 0V, VS+ = VCC + 1.4V unless otherwise specified. (Note 5)
SYMBOL
PARAMETER
CONDITIONS
VS–, VS+
Sense Amplifier Supply Voltage
VCC = 2.7V
l
4.1
VSENSE
Input Sense Voltage Full Scale
VSENSE = VS+ – VS–, VCC = 3V, AV = 10V/V
VSENSE = VS+ – VS–, VCC = 5V, AV = 10V/V
l
l
110
300
VOS
Input Offset Voltage (MS Package)
IOUT = 0
–300
–500
±80
l
300
500
µV
µV
–350
–550
±80
l
350
550
µV
µV
0.5
3
Input Offset Voltage (DD Package)
IOUT = 0
VOS TC
Temperature Coefficient of VOS
(Note 6)
AV
Gain, VOUT/VSENSE
VSENSE = 50mV to 80mV, AV = 10V/V
LT6100MS8
LT6100DD8
VS = 48V, VSENSE = 50mV to 80mV, AV = 10V/V
Output Voltage Gain Error (Note 7)
VCC PSRR
l
VS Sense Input Common Mode
Rejection Ratio
VSENSE = 50mV, VCC = 2.7V, VS = 4.1V to 36V
VCC Supply Rejection Ratio
VSENSE = 50mV, VS = 36V, VCC = 3V to 30V
VCC
Supply Voltage VCC
BW
Bandwidth
AV = 10V/V, fO = –3dB, VCC = 15V
AV = 50V/V, fO = –3dB, VCC = 15V
tS
Output Settling to 1% Final Value
VSENSE = 10mV to 100mV
TYP
MAX
48
UNITS
V
mV
mV
µV/°C
l
9.95
9.94
9.90
10.05
10.06
10.10
V/V
V/V
V/V
l
9.90
10.10
V/V
l
–0.5
–0.6
–1.0
0.5
0.6
1.0
%
%
%
l
–1.0
1.0
%
l
105
100
120
120
dB
dB
l
105
100
120
120
dB
dB
l
2.7
VSENSE = 50mV to 80mV,
AV = 10, 12.5, 20, 25, 40, 50V/V
LT6100MS8
LT6100DD8
VS = 48V, VSENSE = 50mV to 80mV,
AV = 10, 12.5, 20, 25, 40, 50V/V
VS CMRR
MIN
100
20
36
150
50
V
kHz
kHz
15
µs
IS+(O), IS–(O) Sense Input Current
VSENSE = 0V
l
4.5
10
µA
ICC(O)
VCC Supply Current
VSENSE = 0V
l
60
130
µA
SR
Slew Rate (Note 8)
VCC = 15V, VSENSE = 26mV to 380mV, AV = 50V/V
l
0.03
0.02
0.05
0.05
V/µs
V/µs
8
15
mA
50
60
V
Short-Circuit Current
ISC+, ISC–
Reverse VS Supply
IS(TOTAL) = –200µA, VCC = Open
l
VO(MIN)
Minimum Output Voltage
VSENSE = 0V, No Load
VSENSE = VS+ – VS– = –100mV, AV = 50V/V, No Load
l
15
15
30
25
mV
mV
VO(MAX)
Output High (Referred to VCC)
AV = 50V/V, VSENSE = 100mV, IL = 0
VSENSE = 100mV, IL = 100µA
VSENSE = 100mV, IL = 500µA
VSENSE = 100mV, IL = 1mA
l
l
l
l
75
85
125
175
125
150
250
400
mV
mV
mV
mV
VCC = 0V, VS = 48V, VSENSE = 0V
l
0.001
1
µA
ISC
IS+, IS– (Off) Sense Input Current (Power Down)
6100fd
For more information www.linear.com/LT6100
3
LT6100
ELECTRICAL CHARACTERISTICS
The l denotes specifications which apply over the temperature range –40°C ≤ TA ≤ 85°C (LT6100I), otherwise specifications are
TA = 25°C. VCC = 5V, VEE = 0V, VS+ = VCC + 1.4V unless otherwise specified. (Note 5)
SYMBOL
PARAMETER
CONDITIONS
VS–, VS+
Sense Amplifier Supply Voltage
VCC = 2.7V
l
4.1
VSENSE
Input Sense Voltage Full Scale
VSENSE = VS+ – VS–, VCC = 3V, AV = 10V/V
VSENSE = VS+ – VS–, VCC = 5V, AV = 10V/V
l
l
110
300
VOS
Input Offset Voltage (MS Package)
IOUT = 0
–300
–550
±80
l
300
550
µV
µV
–350
–600
±80
l
350
600
µV
µV
0.5
3
Input Offset Voltage (DD Package)
IOUT = 0
VOS TC
Temperature Coefficient of VOS
(Note 6)
AV
Gain, VOUT/VSENSE
VSENSE = 50mV to 80mV, AV = 10V/V
LT6100MS8
LT6100DD8
VS = 48V, VSENSE = 50mV to 80mV, AV = 10V/V
Output Voltage Gain Error (Note 7)
VCC PSRR
l
VS Sense Input Common Mode
Rejection Ratio
VSENSE = 50mV, VCC = 2.7V, VS = 4.1V to 36V
VCC Supply Rejection Ratio
VSENSE = 50mV, VS = 36V, VCC = 3V to 30V
TYP
MAX
48
UNITS
V
mV
mV
µV/°C
l
9.95
9.94
9.90
10.05
10.06
10.10
V/V
V/V
V/V
l
9.90
10.10
V/V
l
–0.5
–0.6
–1.0
0.5
0.6
1.0
%
%
%
l
–1.0
1.0
%
l
105
100
120
120
dB
dB
l
105
100
120
120
dB
dB
l
2.7
VSENSE = 50mV to 80mV,
AV = 10, 12.5, 20, 25, 40, 50V/V
LT6100MS8
LT6100DD8
VS = 48V, VSENSE = 50mV to 80mV,
AV = 10, 12.5, 20, 25, 40, 50V/V
VS CMRR
MIN
VCC
Supply Voltage VCC
BW
Bandwidth
AV = 10V/V, fO = –3dB, VCC = 15V
AV = 50V/V, fO = –3dB, VCC = 15V
tS
Output Settling to 1% Final Value
VSENSE = 10mV to 100mV
IS+(O), IS–(O)
Sense Input Current
VSENSE = 0V
l
4.5
10
µA
ICC(O)
Supply Current
VSENSE = 0V
l
60
145
µA
SR
Slew Rate (Note 8)
VCC = 15V, VSENSE = 26mV to 380mV, AV = 50V/V
100
20
l
36
V
150
50
kHz
kHz
15
µs
0.03
0.02
0.05
0.05
V/µs
V/µs
8
15
mA
ISC
Short-Circuit Current
ISC+, ISC–
Reverse VS Supply
IS(TOTAL) = –200µA, VCC = Open
l
VO(MIN)
Minimum Output Voltage
VSENSE = 0V, No Load
VSENSE = VS+ – VS– = –100mV, AV = 50V/V, No
Load
l
15
15
30
25
mV
mV
VO(MAX)
Output High (Referred to VCC)
AV = 50V/V, VSENSE = 100mV, IL = 0
VSENSE = 100mV, IL = 100µA
VSENSE = 100mV, IL = 500µA
VSENSE = 100mV, IL = 1mA
l
l
l
l
75
85
125
175
125
150
250
400
mV
mV
mV
mV
IS+, IS– (Off)
Sense Input Current (Power Down)
VCC = 0V, VS = 48V, VSENSE = 0V
l
0.001
1
µA
50
60
V
6100fd
4
For more information www.linear.com/LT6100
LT6100
ELECTRICAL CHARACTERISTICS
The l denotes specifications which apply over the temperature range –40°C ≤ TA ≤ 125°C (LT6100H), otherwise specifications are
TA = 25°C. VCC = 5V, VEE = 0V, VS+ = VCC + 1.4V unless otherwise specified. (Note 5)
SYMBOL
PARAMETER
CONDITIONS
VS–, VS+
Sense Amplifier Supply Voltage
VSENSE
Input Sense Voltage Full Scale
VOS
Input Offset Voltage (MS Package)
IOUT = 0
Input Offset Voltage (DD Package)
4.1
110
300
–300
–600
±80
l
300
600
µV
µV
–350
–650
±80
l
350
650
µV
µV
0.5
5
IOUT = 0
AV
Gain, VOUT/VSENSE
VSENSE = 50mV to 80mV, AV = 10V/V
LT6100MS8
LT6100DD8
VS = 48V, VSENSE = 50mV to 80mV, AV = 10V/V
l
VS Sense Input Common Mode
Rejection Ratio
VSENSE = 50mV, VCC = 2.7V, VS = 4.1V to 36V
VCC Supply Rejection Ratio
VSENSE = 50mV, VS = 36V, VCC = 3V to 30V
VCC
Supply Voltage VCC
BW
Bandwidth
AV = 10V/V, fO = –3dB, VCC = 15V
AV = 50V/V, fO = –3dB, VCC = 15V
V
mV
mV
µV/°C
l
9.95
9.94
9.90
10.05
10.06
10.10
V/V
V/V
V/V
l
9.90
10.10
V/V
l
–0.5
–0.6
–1.0
0.5
0.6
1.0
%
%
%
l
–1.0
1.0
%
l
105
100
120
120
dB
dB
l
105
95
120
120
dB
dB
VSENSE = 50mV to 80mV,
AV = 10, 12.5, 20, 25, 40, 50V/V
LT6100MS8
LT6100DD8
VS = 48V, VSENSE = 50mV to 80mV,
AV = 10, 12.5, 20, 25, 40, 50V/V
48
UNITS
l
l
(Note 6)
VCC PSRR
MAX
VSENSE = VS+ – VS–, VCC = 3V, AV = 10V/V
VSENSE = VS+ – VS–, VCC = 5V, AV = 10V/V
Temperature Coefficient of VOS
VS CMRR
TYP
VCC = 2.7V
VOS TC
Output Voltage Gain Error (Note 7)
MIN
l
l
2.7
100
20
tS
Output Settling to 1% Final Value
VSENSE = 10mV to 100mV
IS+(O), IS–(O)
Sense Input Current
VSENSE = 0V
l
ICC(O)
Supply Current
VSENSE = 0V
l
SR
Slew Rate (Note 8)
VCC = 15V, VSENSE = 26mV to 380mV, AV = 50V/V
Short-Circuit Current
ISC+, ISC–
Reverse VS Supply
VO(MIN)
36
150
50
V
kHz
kHz
15
µs
4.5
10
60
170
µA
µA
l
0.03
0.02
0.05
0.05
V/µs
V/µs
8
15
mA
IS(TOTAL) = –200µA, VCC = Open
l
50
60
V
Minimum Output Voltage
VSENSE = 0V, No Load
VSENSE = VS+ – VS– = –100mV, AV = 50V/V, No
Load
l
15
15
35
25
mV
mV
VO(MAX)
Output High (Referred to VCC)
AV = 50V/V, VSENSE = 100mV, IL = 0
VSENSE = 100mV, IL = 100µA
VSENSE = 100mV, IL = 500µA
VSENSE = 100mV, IL = 1mA
l
l
l
l
75
85
125
175
140
160
250
400
mV
mV
mV
mV
IS+, IS– (Off)
Sense Input Current (Power Down)
VCC = 0V, VS = 48V, VSENSE = 0V
l
0.001
1
µA
ISC
6100fd
For more information www.linear.com/LT6100
5
LT6100
ELECTRICAL CHARACTERISTICS
Note 5: The LT6100C is guaranteed to meet specified performance from
0°C to 70°C. The LT6100C is designed, characterized and expected to
meet specified performance from –40°C to 85°C but is not tested or
QA sampled at these temperatures. The LT6100I is guaranteed to meet
specified performance from –40°C to 85°C. The LT6100H is guaranteed to
meet specified performance from –40°C to 125°C.
Note 6: This parameter is not 100% tested.
Note 7: Gain error for AV = 12.5, 25V/V is guaranteed by the other gain
error tests.
Note 8: Slew rate is measured on the output between 3.5V and 13.5V.
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: ESD (Electrostatic Discharge) sensitive devices. Extensive use of
ESD protection devices are used internal to the LT6100, however, high
electrostatic discharge can damage or degrade the device. Use proper ESD
handling precautions.
Note 3: A heat sink may be required to keep the junction temperature
below absolute maximum ratings.
Note 4: The LT6100C/LT6100I are guaranteed functional over the
operating temperature range of –40°C to 85°C. The LT6100H is guaranteed
functional over the operating temperature range of –40°C to 125°C.
TYPICAL PERFORMANCE CHARACTERISTICS
9 TYPICAL UNITS
VS = 6.4V
VCC = 5V
200
100
0
–100
–200
TA = –40°C
0.5
TA = 25°C
0
–0.5
TA = 125°C
–1.0
TA = 85°C
–1.5
–2.0
–2.5
–300
–3.0
– 400
–40 –25 –10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
–3.5
0
OUTPUT VOLTAGE (V)
1.4
10
40
30
20
VS+ INPUT VOLTAGE (V)
1.2
1.0
0.8
TA = –40°C
VS = 4.4V
0.6
0.4
–90
–30
30
90
SENSE VOLTAGE (VS+ – VS–)(mV)
150
6100 G03
TA = –40°C
200
VSENSE = 100mV
VS+ = 48V
150
100
0
50
TA = 125°C
0
5
10 15 20 25 30
VCC SUPPLY VOLTAGE (V)
Gain vs Temperature
TA = –40°C
VS > 6.6V
50.04
50.02
2.5
TA = –40°C
VS = 6.4V
2.0
1.5
50.00
7 TYPICAL UNITS
VSENSE = 50mV TO 80mV
VS+ = 6.4V TO 48V
VCC = 5V
AV = 50V/V
49.98
49.96
49.94
1.0
0
40
35
6100 G02
50.06
49.92
0.5
0.2
0
–150
VS+ = 6.4V TO 48V
VCC = 5V
TA = –40°C TO 125°C
3.0
TA = –40°C
VS > 4.6V
TA = 25°C
250
Output Voltage vs Sense Voltage
3.5
OUTPUT VOLTAGE (V)
1.6
TA = 85°C
300
6100 G01
Output Voltage vs Sense Voltage
VS+ = 4.4V TO 48V
VCC = 3V
AV = 10V/V
TA = –40°C TO 125°C
Input Offset Voltage
vs VCC Supply Voltage
50
6100 G21
1.8
350
VSENSE = 100mV
VCC = 3V
1.0
GAIN (V/V)
INPUT OFFSET VOLTAGE (µV)
300
1.5
INPUT OFFSET VOLTAGE (mV)
400
Input Offset Voltage
vs VS+ Input Voltage
INPUT OFFSET VOLTAGE (µV)
Input Offset Voltage
vs Temperature
49.90
0
300
180
240
120
60
SENSE VOLTAGE (VS+ – VS–) (mV)
6100 G04
49.88
–40 –25 –10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
6100 G05
6100fd
6
For more information www.linear.com/LT6100
LT6100
TYPICAL PERFORMANCE CHARACTERISTICS
VS+ = 4.4V TO 48V
VCC = 3V
10
8
TA = 125°C
6
TA = 85°C
4
TA = 25°C
TA = –40°C
2
0
–110
35
POSITIVE SENSE INPUT CURRENT (µA)
NEGATIVE SENSE INPUT CURRENT (µA)
12
Positive Sense Input Current
vs Sense Voltage
350
VS+ = 4.4V TO 48V
VCC = 3V
30
TA = 125°C
25
TA = 85°C
20
TA = 25°C
15
TA = –40°C
10
5
0
–5
30
70
110
–70 –30
SENSE VOLTAGE (VS+ – VS–) (mV)
–110
10k
TA = 85°C
120
TA = 25°C
100
TA = –40°C
80
60
40
1k
0
40
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
LOAD CURRENT (mA)
G2 = 2V/V
10
AV = 10
20
G2 = 5V/V
VS = 12.1V
VCC = 10V
AV = 50
30
100
10
0
–10
–20
G2 = 1V/V
–30
1
–40
0
10
30
40
20
TOTAL VS INPUT VOLTAGE (V)
0.1
50
10k
1k
100k
150
60
VS = 10V
VSENSE = 100mV
VCC = 5V
70
50
30
20
10
100
1k
10k
FREQUENCY (Hz)
100k
1M
6100 G11
0
90
40
–10
0.1
10M
Gain Error vs VSENSE
GAIN ERROR (%)
VCC PSRR (dB)
80
1M
1
110
100
10k
100k
FREQUENCY (Hz)
6100 G10
VCC PSRR vs Frequency
130
120
10
1k
6100 G23
VS = 6.4V
VCC = 5V
140
–50
100
1M
FREQUENCY (Hz)
CMRR vs Frequency
CMRR (dB)
TA = –40°C
50
Gain vs Frequency
VS+, VS– = 6.5V
VCC = 5V
VEE = –5V
FIL = 0V
6100 G09
0
TA = 25°C
100
50
20
0
150
6100 G08
GAIN (dB)
OUTPUT IMPEDANCE (Ω)
VCC SUPPLY CURRENT (µA)
TA = 125°C
TA = 85°C
200
Op Amp Output Impedance
vs Frequency
VSENSE = 0V
180 VCC = 3V
140
250
TA = 125°C
6100 G07
VCC Supply Current vs
VS Input Voltage
160
VS+ = 6.4V
VCC = 5V
VSENSE = 150mV
AV = 50V/V
300
0
110
–70 –30
30
70
SENSE VOLTAGE (VS+ – VS–) (mV)
6100 G06
200
Output Positive Swing
vs Load Current
OUTPUT POSITIVE SWING (mV)
Negative Sense Input Current
vs Sense Voltage
–1
–2
1
10
100 1k 10k 100k
FREQUENCY (Hz)
1M
6100 G12
–3
VS+ = 6.4V
VCC = 5V
AV = 10V/V
TA = 25°C
0
50
100
150
200
VSENSE (mV)
250
300
6100 G24
6100fd
For more information www.linear.com/LT6100
7
LT6100
TYPICAL PERFORMANCE CHARACTERISTICS
TOTAL INPUT CURRENT (IS+ + IS–) (nA)
10
Sense Input Current (VCC Powered
Down) vs VS+
Step Response at VSENSE = 0V to
130mV
VS+ = VS–
10V
10V
TA = 125°C
1
TA = 85°C
VOUT
500mV/DIV
VOUT
2V/DIV
0V
0V
TA = 25°C
0.01
VS+ = 10V
AV = 10V/V
CL = 0pF
TA = –40°C
0
10
20
30
VS+ (V)
V–
100mV/DIV
V–
50mV/DIV
0.1
0.001
Step Response at VSENSE = 0V to
130mV
40
50
6100 G13
50µs/DIV
VS+ = 10V
AV = 50V/V
CL = 0pF
0.2ms/DIV
6100 G14
6100 G25
Step Response at VSENSE = 0V to
10mV
Step Response at VSENSE = 0V to
10mV
Step Response at VSENSE = 0V to
130mV
10V
10V
V–
20mV/DIV
10V
V–
20mV/DIV
VOUT
50mV/DIV
0V
VOUT
200mV/DIV
V–
50mV/DIV
VOUT
500mV/DIV
0V
0V
VS+ = 10V
AV = 10V/V
COUT = 0pF
50µs/DIV
6100 G15
VS+ = 10V
AV = 50V/V
CL = 0pF
6100 G16
50µs/DIV
Step Response at VSENSE = 0V to
130mV
VS+ = 10V
AV = 10V/V
COUT = 1000pF
50µs/DIV
6100 G17
Step Response at VSENSE = 0V to
10mV
10V
10V
V–
20mV/DIV
V–
100mV/DIV
VOUT
2V/DIV
VOUT
50mV/DIV
0V
0V
VS+ = 10V
AV = 50V/V
CL = 1000pF
0.2ms/DIV
6100 G18
VS+ = 10V
AV = 10V/V
CL = 1000pF
50µs/DIV
6100 G19
6100fd
8
For more information www.linear.com/LT6100
LT6100
TYPICAL PERFORMANCE CHARACTERISTICS
Step Response at VSENSE = 0V to
10mV
Start-Up Delay
10V
V–
20mV/DIV
VS+
VOUT
200mV/DIV
VOUT
10V
0V
1V
0V
0V
VS+ = 10V
AV = 50V/V
CL = 1000pF
50µs/DIV
6100 G20
VCC = 5V
VSENSE = 100mV
AV = 10V/V
VEE = 0V
20µs/DIV
6100 G22
PIN FUNCTIONS
VS– (Pin 1): Negative Sense Input Terminal. Negative
sense voltage input will remain functional for voltages
up to 48V. VS– is connected to an internal gain-setting
resistor RG1 = 5k.
VCC (Pin 2): Supply Voltage Input. This power supply pin
supplies current to both current sense amplifier and op amp.
FIL (Pin 3): Filter Pin. Connects to an external capacitor
to roll off differential noise of the system. Pole frequency
f–3dB = 1/(2πRFILC), RFIL = RE + RO = 60k.
VEE (Pin 4): Negative Supply or Ground for Single Supply
Operation.
A2 (Pin 6): Gain Select Pin. Refer to Table 1.
A4 (Pin 7): Gain Select Pin. When Pin 7 is shorted to VEE,
the total gain is 40V/V. When both Pin 6 and Pin 7 are
shorted to VEE, the total gain is 50V/V. When both Pin 6
and Pin 7 are opened, the total gain is 10V/V.
VS+ (Pin 8): Positive Sense Input Terminal. Connecting a
supply to VS+ and a load to VS– will allow the LT6100 to
monitor the current through RSENSE, refer to Figure 1. VS+
is connected to an internal gain setting resistor RG2 = 5k.
VS+ remains functional for voltages up to 48V.
VOUT (Pin 5): Voltage Output Proportional to the Magnitude
of the Current Flowing Through RSENSE:
VOUT = AV • (VSENSE ± VOS)
VOS is the input offset voltage. AV is the total gain of the
LT6100.
6100fd
For more information www.linear.com/LT6100
9
LT6100
FUNCTIONAL DIAGRAM
RSENSE
LOAD
1
VIN
(VCC + 1.4V) TO 48V
8
VS–
RG1
5k
VS+
RG2
5k
+
–
R
25k
A1
VCC
2.7V TO 36V
–
2
VO1
Q1 RE
10k
+
RO
50k
R
VEE
4
FIL
3
VOUT
5
R/3
A2
6
A2
A4
7
6100 F01
Figure 1. Functional Diagram
6100fd
10
For more information www.linear.com/LT6100
LT6100
APPLICATIONS INFORMATION
The LT6100 high side current sense amplifier (Figure 1)
provides accurate unidirectional monitoring of current
through a user-selected sense resistor. The LT6100 features a fully specified 4.1V to 48V input common mode
range. A high PSRR VCC supply (2.7V to 36V) powers the
current sense amplifier and the internal op amp circuitry.
The input sense voltage is level shifted from the positive
sense power supply to the ground reference and amplified
by a user-selected gain to the output. The buffered output
voltage is directly proportional to the current flowing
through the sense resistor.
Theory of Operation (Refer to Figure 1)
Current from the source at VS+ flows through RSENSE to
the load at VS–, creating a sense voltage, VSENSE. Inputs
VS+ and VS– apply the sense voltage to RG2. The opposite
ends of resistors RG1 and RG2 are forced to be at equal
potentials by the voltage gain of amplifier A1. The current
through RG2 is forced to flow through transistor Q1 and is
sourced to node VO1. The current from RG2 flowing through
resistor RO gives a voltage gain of ten, VO1/VSENSE = RO/
RG2 = 10V/V. The sense amplifier output at VO1 is amplified again by amplifier A2. The inputs of amplifier A2 can
operate to ground which ensures that small sense voltage
signals are detected. Amplifier A2 can be programmed to
different gains via Pin 6 and Pin 7. Thus, the total gain of
the system becomes AV = 10 • A2 and VOUT = VSENSE • AV .
Gain Setting
The LT6100 gain is set by strapping (or floating) the two
gain pins (see Table 1). This feature allows the user to
“zoom in” by increasing the gain for accurate measurement of low currents.
Table 1. Gain Set with Pin 6 and Pin 7
A2 (PIN 6)
A4 (PIN 7)
G2
AV
Open
Open
1
10
VEE
Out
1.25
12.5
VEE
Open
2
20
Out
VEE
2.5
25
Open
VEE
4
40
VEE
VEE
5
50
Selection of External Current Sense Resistor
External RSENSE resistor selection is a delicate trade-off
between power dissipation in the resistor and current measurement accuracy. The maximum sense voltage may be
as large as ±300mV to get maximum dynamic range. For
high current applications, the user may want to minimize
the sense voltage to minimize the power dissipation in
the sense resistor. The LT6100’s low input offset voltage
of 80µV allows for high resolution of low sense voltages.
This allows limiting the maximum sense voltage while still
providing high resolution current monitoring.
Kelvin connection of the LT6100’s VS+ and VS– inputs to
the sense resistor should be used to provide the highest
accuracy in high current applications. Solder connections
and PC board interconnect resistance (approximately
0.5mΩ per square) can be a large error in high current
systems. A 5A application might choose a 20mΩ sense
resistor to give a 100mV full-scale input to the LT6100.
Input offset voltage will limit resolution to 4mA. Neglecting contact resistance at solder joints, even one square
of PC board copper at each resistor end will cause an
error of 5%. This error will grow proportionately higher
as monitored current levels rise.
AV = 10V/V • G2, G2 is the gain of op amp A2.
6100fd
For more information www.linear.com/LT6100
11
LT6100
APPLICATIONS INFORMATION
The LT6100 provides signal filtering via pin FIL that is
internally connected to the resistors RE and RO. This pin
may be used to filter the input signal entering the LT6100’s
internal op amp, and should be used when fast ripple current or transients flow through the sense resistor. High
frequency signals above the 300kHz bandwidth of the
LT6100’s internal amplifier will cause errors. A capacitor
connected between FIL and VEE creates a single pole low
pass filter with corner frequency:
f–3dB = 1/(2πRFILC)
where RFIL = 60k. A 220pF capacitor creates a pole at
12kHz, a good choice for many applications.
Output Signal Range
The LT6100’s output signal is developed by current through
RG2 into output resistor RO. The current is VSENSE/RG2. The
sense amplifier output, VO1, is buffered by the internal op
amp so that connecting the output pins to other systems will
preserve signal accuracy. For zero VSENSE, internal circuit
saturation with loss of accuracy occurs at the minimum
VOUT swing, 15mV above VEE. VOUT may swing positive
to within 75mV of VCC or a maximum of 36V, a limit set
by internal junction breakdown. Within these constraints,
1.5
Sense Input Signal Range
The LT6100 has high CMRR over the wide input voltage
range of 4.1V to 48V. The minimum operation voltage of
the sense amplifier input is 1.4V above VCC. The output
remains accurate even when the sense inputs are driven
to 48V. Figure 2 shows that VOS changes very slightly
over a wide input range. Furthermore, the sense inputs
VS+ and VS– can collapse to zero volts without incurring
any damage to the device. The LT6100 can handle differential sense voltages up to the voltage of the sense
inputs supplies. For example, VS+ = 48V and VS– = 0V can
be a valid condition in a current monitoring application
(Figure 3) when an overload protection fuse is blown and
VS– voltage collapses to ground. Under this condition, the
output of the LT6100 goes to the positive rail, VOH. There
is no phase inversion to cause an erroneous output signal.
For the opposite case when VS+ collapse to ground with
VS– held up at some higher voltage potential, the output
will sit at VOL. If both inputs fall below the minimum CM
voltage, VCC + 1.4V, the output is indeterminate but the
LT6100 will not be damaged.
TO LOAD
VSENSE = 100mV
VCC = 3V
TA = 25°C
1.0
0.5
RSENSE FUSE
0
–0.5
+
–1.0
–1.5
2
5V
C2
0.1µF
3
–2.0
1
8
VS–
VS+
VCC
C1
0.1µF
A4
–
INPUT OFFSET VOLTAGE (mV)
an amplified, level shifted representation of the RSENSE
voltage is developed at VOUT . The output is well behaved
driving capacitive loads to 1000pF.
DC
SOURCE
7
+
Noise Filtering
A2
FIL
6
–2.5
–3.0
–3.5
4
0
10
40
30
20
VS INPUT VOLTAGE (V)
50
VEE
OUT 5
OUTPUT
LT6100
6100 F03
6100 F02
Figure 2. VOS vs VS Input Voltage
Figure 3. Current Monitoring of a Fuse Protected Circuit
6100fd
12
For more information www.linear.com/LT6100
LT6100
APPLICATIONS INFORMATION
Low Sense Voltage Operation
Figure 4 shows the simplest circuit configuration in which
the LT6100 may be used. While VOUT (output voltage)
increases with positive sense current, at VSENSE = 0V,
the LT6100’s buffered output can only swing as low as
1.6
TO LOAD
8
VS–
VS+
VCC
C1
0.1µF
A4
+
A2
FIL
VS = 4.4V TO 48V
VCC = 3V
AV = 10V/V
TA = 25°C
1.4
5V
7
6
OUTPUT VOLTAGE (V)
3
1
–
C2
0.1µF
3V
RSENSE
+
+
2
VOL = 15mV. The accuracy at small sense voltages can be
improved by selecting higher gain. When gain of 50V/V
is selected, as shown in Figure 7, VOUT leaves the clipped
region for a positive VSENSE greater than 1mV compared
to 2.5mV for gain of 10V/V (see Figure 6).
1.2
1.0
0.8
0.6
0.4
0.2
4
OUT 5
VEE
0
OUTPUT
LT6100
0
6100 F04
30
60
120
90
SENSE VOLTAGE (VS+ – VS–) (mV)
150
6100 F05
Figure 4. LT6100 Load Current Monitor
0.40
0.30
VS = 4.4V TO 48V
VCC = 3V
AV = 50V/V
TA = 25°C
1.6
1.4
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
1.8
VS = 4.4V TO 48V
VCC = 3V
AV = 10V/V
TA = 25°C
0.35
0.25
0.20
0.15
0.10
1.2
1.0
0.8
0.6
0.4
0.05
0
Figure 5. Output Voltage vs VSENSE
0.2
0
5
10
20
25
15
SENSE VOLTAGE (VS+ – VS–) (mV)
30
0
0
6100 F06
Figure 6. Expanded View of Output Voltage vs VSENSE, AV = 10V/V
10
5
15
20
25
SENSE VOLTAGE (VS+ – VS–) (mV)
30
6100 F07
Figure 7. Expanded View of Output Voltage vs VSENSE, AV = 50V/V
6100fd
For more information www.linear.com/LT6100
13
LT6100
APPLICATIONS INFORMATION
Power Down While Connected to a Battery
its inputs remain high impedance (see Figure 8). This is
due to the implementation of Linear Technology’s OverThe-Top® input topology at its front end. When powered
down, the LT6100 inputs draw less than 1µA of current.
Another unique benefit of the LT6100 is that you can leave it
connected to a battery even when it is denied power. When
the LT6100 loses power or is intentionally powered down,
ISENSE
RSENSE
TO LOAD
–
LT6100 VS
BATTERY
4.1V TO 48V
–
+
POWER
DOWN OK
VCC
3V
0V
INPUTS
REMAIN
Hi-Z
+
VS+
VCC
FIL
VOUT
VEE
A2
A4
6100 F08
Figure 8. Input Remains Hi-Z when LT6100 is Powered Down
TYPICAL APPLICATION
Micro-Hotplate Voltage and Current Monitor
Adjust Gain Dynamically for Enhanced Range
VS+
VS
10Ω
1%
VS–
IHOTPLATE
–
+
5V
FROM SOURCE
–
VCC
5V
FIL
A2
2N7002
A4
MICRO-HOTPLATE
BOSTON
MICROSYSTEMS
MHP100S-005
6100 TA05
0V
(GAIN = 10)
VCC
VEE
VOUT
VEE
5V
5V
(GAIN = 50)
VDR–
VS+
+ –
LT6100
VDR+
ISENSE
RSENSE
TO LOAD
LT6100
A2 A4
CURRENT
MONITOR
VOUT = 500mV/mA
5V
M9
M3
M1
P1
P3
P9
LT1991
VOLTAGE
MONITOR
V + – VDR–
VOUT = DR
10
6100 TA06
www.bostonmicrosystems.com
6100fd
14
For more information www.linear.com/LT6100
LT6100
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
DD Package
8-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1698 Rev C)
0.70 ±0.05
3.5 ±0.05
1.65 ±0.05
2.10 ±0.05 (2 SIDES)
PACKAGE
OUTLINE
0.25 ±0.05
0.50
BSC
2.38 ±0.05
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
PIN 1
TOP MARK
(NOTE 6)
0.200 REF
3.00 ±0.10
(4 SIDES)
R = 0.125
TYP
5
0.40 ±0.10
8
1.65 ±0.10
(2 SIDES)
0.75 ±0.05
4
0.25 ±0.05
1
(DD8) DFN 0509 REV C
0.50 BSC
2.38 ±0.10
0.00 – 0.05
BOTTOM VIEW—EXPOSED PAD
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON TOP AND BOTTOM OF PACKAGE
6100fd
For more information www.linear.com/LT6100
15
LT6100
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
MS8 Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1660 Rev G)
0.889 ±0.127
(.035 ±.005)
5.10
(.201)
MIN
3.20 – 3.45
(.126 – .136)
3.00 ±0.102
(.118 ±.004)
(NOTE 3)
0.65
(.0256)
BSC
0.42 ± 0.038
(.0165 ±.0015)
TYP
8
7 6 5
0.52
(.0205)
REF
RECOMMENDED SOLDER PAD LAYOUT
0.254
(.010)
3.00 ±0.102
(.118 ±.004)
(NOTE 4)
4.90 ±0.152
(.193 ±.006)
DETAIL “A”
0° – 6° TYP
GAUGE PLANE
0.53 ±0.152
(.021 ±.006)
DETAIL “A”
1
2 3
4
1.10
(.043)
MAX
0.86
(.034)
REF
0.18
(.007)
SEATING
PLANE
0.22 – 0.38
(.009 – .015)
TYP
0.65
(.0256)
BSC
0.1016 ±0.0508
(.004 ±.002)
MSOP (MS8) 0213 REV G
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
6100fd
16
For more information www.linear.com/LT6100
LT6100
REVISION HISTORY
(Revision history begins at Rev C)
REV
DATE
DESCRIPTION
C
11/12
Corrected value in Output Signal Range section.
PAGE NUMBER
11
D
07/14
Corrected part numbers in Order Information
2
Corrected Specified Temperature Range for LT6100C
2
Updated format of Order Information
2
Added web links
All
6100fd
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection
of its circuits
as described
herein will not infringe on existing patent rights.
For more
information
www.linear.com/LT6100
17
LT6100
TYPICAL APPLICATIONS
800mA/1A White LED Current Regulator
D2
LED
L1
3µH
VIN
D1
B130
0.030Ω
FB
SHDN
GND
124k
VC
+ –
22µF
16V
CER
1210
0.1µF
8.2k
VEE
6100 TA02
ISENSE
VSUPPLY
6.4V TO 48V
VS–
LOAD
LT6100
–
+
3V
Gain of 50 Current Sense
RSENSE
VS+
VCC
5V
FIL
RSENSE
VS+
VS–
LOAD
VCC
FIL
VOUT
20 • RSENSE • ISENSE
1000pF
VEE
A2
+
LT6100
A4
OPEN: 1A
CLOSED: 800mA
Filtered Gain of 20 Current Sense
ISENSE
VCC
4.99k
D1: DIODES INC.
D2: LUMILEDS LXML-PW09 WHITE EMITTER
L1: SUMIDA CDRH6D28-3R0
VSUPPLY
4.4V TO 48V
VS–
VOUT
MMBT2222
4.7µF
6.3V
CER
LT6100
VSW
LT3436
LED
ON
VS+
–
VIN
3.3V TO 4.2V
SINGLE Li-Ion
LED
CURRENT
WARNING! VERY BRIGHT
DO NOT OBSERVE DIRECTLY
A2
A4
VEE
6100 TA03
A2
VOUT
50 • RSENSE • ISENSE
A4
6100 TA04
–3dB AT 2.6kHz
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC 1043
Dual Precision Instrumentation Switched Capacitor Building Block
120dB CMRR, 3V to 18V Operation
LT1490/LT1491
Dual and Quad Micropower Rail-to-Rail Input and Output Op Amps 50µA Amplifier, 2.7V to 40V Operation, Over-The-Top Inputs
LT1620/LT1621
Rail-to-Rail Current Sense Amplifiers
Accurate Output Current Programming, Battery Charging
to 32V
LT1787
Precision Bidirectional, High Side Current Sense Amplifier
75µV VOS, 60V, 60µA Operation
®
LTC6101/LTC6101HV High Voltage, High Side, Precision Current Sense Amplifiers
4V to 60V/5V to 100V, Gain Configurable, SOT-23
6100fd
18
Linear Technology Corporation
LT 0714 REV D • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
For more information www.linear.com/LT6100
www.linear.com/LT6100
LINEAR TECHNOLOGY CORPORATION 2005
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