LT6105
Precision, Extended Input
Range Current Sense Amplifier
FEATURES
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DESCRIPTION
The LT
®
6105 is a micropower, precision current sense
amplifier with a very wide input common mode range.
The LT6105 monitors unidirectional current via the volt-
age across an external sense resistor. The input common
mode range extends from –0.3V to 44V, with respect to
the negative supply voltage (V
–
). This allows the LT6105
to operate as a high side current sense monitor or a low
side current sense monitor. It also allows the LT6105 to
monitor current on a negative supply voltage, as well as
continuously monitor a battery from full charge to depletion.
The inputs of LT6105 can withstand differential voltages
up to ±44V, which makes it ideal for monitoring a fuse or
MOSFET switch.
Gain is configured with external resistors from 1V/V to
100V/V. The input common mode rejection and power
supply rejection are in excess of 100dB and the input offset
voltage is less than 300μV. A typical slew rate of 2V/μs
ensures fast response to unexpected current changes.
The LT6105 can operate from an independent power
supply of 2.85V to 36V and draws only 150μA. When
V
+
is powered down, the sense pins are biased off. This
prevents loading of the monitored circuit, irrespective of
the sense voltage. The LT6105 is available in a 6-lead DFN
and 8-lead MSOP package.
, LT, LTC, LTM and Over-the-Top are registered trademarks of Linear Technology
Corporation. All other trademarks are the property of their respective owners.
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Very Wide, Over-the-Top
®
, Input Common Mode Range
- Extends 44V Above V
–
(Independent of V
+
)
- Extends –0.3V Below V
–
Wide Power Supply Range: 2.85V to 36V
Input Offset Voltage: 300μV Maximum
Gain Accuracy: 1% Max
Gain Configurable with External Resistors
Operating Current: 150μA
Slew Rate: 2V/μs
Sense Input Current When Powered Down: 1nA
Full-Scale Output Current: 1mA Minimum
Operating Temperature Range –40°C to 125°C
Available in 2mm
×
3mm DFN and 8-Lead MSOP
Packages
APPLICATIONS
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High Side or Low Side Current Sensing
Current Monitoring on Positive or Negative Supply
Voltages
Battery Monitoring
Fuse/MOSFET Monitoring
Automotive
Power Management
Portable Test/Measurement Systems
TYPICAL APPLICATION
Gain of 50 Current Sense Amplifier
SOURCE
–0.3V TO 44V
R
IN2
V
S+
100Ω
0.02Ω
R
IN1
100Ω
LT6105
GAIN ERROR (%)
+IN
4
Gain Error vs Input Voltage
V
+
= 12V
3 V
SENSE
= 50mV
R
IN
= 100Ω
A
V
= 50V
2
1
0
–1
–2
–3
6105 TA01
T
A
= – 40°C
T
A
= 25°C
+
–
V
+
V
OUT
V
OUT
= 1V/A
R
OUT
4.99k
–IN
V
S–
T
A
= 125°C
T
A
= 85°C
V
–
TO LOAD
2.85V TO 36V
V
OUT
=
V
S
−
V
S
(
+
−
)
R
R
•
OUT
; A
V
=
OUT
; R
IN1
=
R
IN 2
=
R
IN
R
IN
R
IN
–4
0
5
10
15
20
25
30
35
40
45
6105fa
V
S+
INPUT VOLTAGE (V)
6105 TA01b
1
LT6105
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Differential Input Voltage (+IN – –IN) .....................±44V
Input Voltage V(+IN, –IN) to V
–
................ –9.5V to 44V
Total V
+
Supply Voltage from V
–
...............................36V
Output Voltage ......................................V
–
to (V
–
+ 36V)
Output Short-Circuit Duration (Note 3) ............ Indefinite
Operating Temperature Range (Note 4)
LT6105C...............................................–40°C to 85°C
LT6105I ................................................–40°C to 85°C
LT6105H ............................................–40°C to 125°C
Specified Temperature Range (Note 5)
LT6105C................................................... 0°C to 70°C
LT6105I ................................................–40°C to 85°C
LT6105H ............................................–40°C to 125°C
Maximum Junction Temperature........................... 150°C
Storage Temperature Range...................–65°C to 150°C
Lead Temperature (Soldering, 10 sec)
MSOP ............................................................... 300°C
PIN CONFIGURATION
TOP VIEW
–IN 1
V
+
2
V
–
3
7
6 +IN
5 NC
4 V
OUT
–IN 1
V
+
2
NC 3
V
–
4
TOP VIEW
8
7
6
5
+IN
NC
NC
V
OUT
DCB PACKAGE
6-LEAD (2mm 3mm) PLASTIC DFN
T
JMAX
= 150°C,
θ
JA
= 64°C/W
EXPOSED PAD (PIN 7) CONNECTED TO V
–
(PIN 3)
MS8 PACKAGE
8-LEAD PLASTIC MSOP
T
JMAX
= 150°C,
θ
JA
= 250°C/W
ORDER INFORMATION
LEAD FREE FINISH
LT6105CDCB#TRMPBF
LT6105IDCB#TRMPBF
LT6105HDCB#TRMPBF
LT6105CMS8#PBF
LT6105IMS8#PBF
LT6105HMS8#PBF
TAPE AND REEL
LT6105CDCB#TRPBF
LT6105IDCB#TRPBF
LT6105HDCB#TRPBF
LT6105CMS8#TRPBF
LT6105IMS8#TRPBF
LT6105HMS8#TRPBF
PART MARKING*
LCTF
LCTF
LCTF
LTCTD
LTCTD
LTCTD
PACKAGE DESCRIPTION
6-Lead (2mm
×
3mm) Plastic DFN
6-Lead (2mm
×
3mm) Plastic DFN
6-Lead (2mm
×
3mm) Plastic DFN
8-Lead Plastic MS8
8-Lead Plastic MS8
8-Lead Plastic MS8
SPECIFIED TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
–40°C to 125°C
0°C to 70°C
–40°C to 85°C
–40°C to 125°C
TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container.
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for parts specified with wider operating temperature ranges.
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/
6105fa
2
LT6105
ELECTRICAL CHARACTERISTICS
SYMBOL
V
S+
, V
S–
A
V
Error
PARAMETER
Input Voltage Range
Voltage Gain Error (Note 6)
The
l
denotes the specifications which apply over the temperature range
0°C < T
A
< 70°C (LT6105C), otherwise specifications are at T
A
= 25°C. V
+
= 12V, V
–
= 0V, V
S+
= 12V (see Figure 1), R
IN1
= R
IN2
= 100Ω,
R
OUT
= 5k (A
V
= 50), V
SENSE
= V
S+
– V
S–
, unless otherwise specified. (Note 5)
CONDITIONS
Guaranteed by CMRR
V
SENSE
= 25mV to 75mV, V
S+
= 12V
V
SENSE
= 25mV to 75mV, V
S+
= 0V
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l
l
l
l
l
l
MIN
–0.3
–0.1
–1
–1.3
–2.5
–0.3
–0.6
–0.4
–0.7
–1
–1.3
100
95
94
90
2.85
98
94
98
94
TYP
MAX
44
44
UNITS
V
V
%
%
%
mV
mV
mV
mV
mV
mV
μV/°C
dB
dB
dB
dB
0.1
1
1.3
2.5
V
OS
Input Offset Voltage
MS8 Package
Input Offset Voltage
DCB Package
Input Offset Voltage
V
SENSE
= 5mV
V
SENSE
= 5mV
V
SENSE
= 5mV, V
S+
= 0V
–0.1
–0.1
–0.3
0.5
120
0.3
0.6
0.4
0.7
1
1.3
ΔV
OS
/ΔT
CMRR
Temperature Coefficient of V
OS
Input Common Mode
Rejection Ratio
V
SENSE
= 5mV, V
S+
= 2.8V to 44V
V
SENSE
= 5mV, V
S+
= –0.3V to 44V
V
SENSE
= 5mV, V
S+
= –0.1V to 44V
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
V
+
PSRR
Power Supply Voltage Range
Power Supply Rejection Ratio
Guaranteed by PSRR
V
SENSE
= 5mV, V
S+
= 12V, V
+
= 2.85V to 36V
V
SENSE
= 5mV, V
S+
= 0V, V
+
= 2.85V to 36V
36
120
120
15
–0.05
0.05
0.005
0.03
200
240
1.25
25
0.5
1
300
350
35
1.5
V
dB
dB
dB
dB
μA
μA
μA
μA
μA
μA
μA
mV
V
mA
mA
I
(+IN)
, I
(–IN)
I
(+IN)
– I
(–IN)
I
(+IN) +
I
(–IN)
I
S
V
O(MIN)
V
O(MAX)
I
OUT
I
SC
BW
t
S
t
r
SR
V
REV
Input Current
Input Offset Current
Input Current (Power-Down)
V
+
Supply Current
Minimum Output Voltage
Output High (Referred to V
+
)
Maximum Output Current
Short-Circuit Output Current
–3dB Bandwidth
Input Step Response (Note 7)
Slew Rate (Note 8)
Reverse Input Voltage
(Referred to V
–
)
V
SENSE
= 0V, V
S+
= 3V
V
SENSE
= 0V, V
S+
= 0V
V
SENSE
= 0V, V
S+
= 3V
V
SENSE
= 0V, V
S+
= 0V
V
+
= 0V, V
S+
= 44V, V
SENSE
= 0V
V
SENSE
= 0V, V
S+
= 3V, V
+
= 2.85V
V
SENSE
= 0V, V
S+
= 3V, V
+
= 36V
V
SENSE
= 0mV, V
S+
= 44V, V
+
= 36V
V
SENSE
= 120mV, A
V
= 100, R
OUT
= 10k
Guaranteed by V
O(MAX)
V
S+
= 44V, V
S–
= 0V, R
OUT
= 0Ω
V
SENSE
= 50mV, A
V
= 10V/V
V
SENSE
= 5mV to 100mV
V
SENSE
= 5mV to 150mV, A
V
= 50V/V, R
IN
= 400Ω
I
(+IN) +
I
(–IN)
= –5mA
1
1.5
100
5
3
1.75
2
–12
kHz
μs
μs
V/μs
V
Output Settling to 1% of Final Value V
SENSE
= 5mV to 100mV
l
–9.5
6105fa
3
LT6105
ELECTRICAL CHARACTERISTICS
SYMBOL
V
S+
, V
S–
A
V
Error
PARAMETER
Input Voltage Range
Voltage Gain Error (Note 6)
The
l
denotes the specifications which apply over the temperature range
–40°C < T
A
< 85°C (LT6105I), otherwise specifications are at T
A
= 25°C. V
+
= 12V, V
–
= 0V, V
S+
= 12V (see Figure 1), R
IN1
= R
IN2
=
100Ω, R
OUT
= 5k (A
V
= 50), V
SENSE
= V
S+
– V
S–
, unless otherwise specified. (Note 5)
CONDITIONS
Guaranteed by CMRR
V
SENSE
= 25mV to 75mV, V
S+
= 12V
V
SENSE
= 25mV to 75mV, V
S+
= 0V
V
OS
Input Offset Voltage
MS8 Package
Input Offset Voltage
DCB Package
Input Offset Voltage
ΔV
OS
/ΔT
CMRR
Temperature Coefficient of V
OS
Input Common Mode
Rejection Ratio
V
SENSE
= 5mV, V
S+
= 2.8V to 44V
V
SENSE
= 5mV, V
S+
= –0.3V to 44V
V
SENSE
= 5mV, V
S+
= –0.1V to 44V
V
+
PSRR
Power Supply Voltage Range
Power Supply Rejection Ratio
Guaranteed by PSRR
V
SENSE
= 5mV, V
S+
= 12V, V
+
= 2.85V to 36V
V
SENSE
= 5mV, V
S+
= 0V, V
+
= 2.85V to 36V
I
(+IN)
, I
(–IN)
I
(+IN)
– I
(–IN)
I
(+IN) +
I
(–IN)
I
S
V
O(MIN)
V
O(MAX)
I
OUT
I
SC
BW
t
S
t
r
SR
V
REV
Input Current
Input Offset Current
Input Current (Power-Down)
V
+
Supply Current
Minimum Output Voltage
Output High (Referred to V
+
)
Maximum Output Current
Short-Circuit Output Current
–3dB Bandwidth
Input Step Response (Note 7)
Slew Rate (Note 8)
Reverse Input Voltage
(Referred to V
–
)
V
SENSE
= 0V, V
S+
= 3V
V
SENSE
= 0V, V
S+
= 0V
V
SENSE
= 0V, V
S+
= 3V
V
SENSE
= 0V, V
S+
= 0V
V
+
= 0V, V
S+
= 44V, V
SENSE
= 0V
V
SENSE
= 0V, V
S+
= 3V, V
+
= 2.85V
V
SENSE
= 0V, V
S+
= 3V, V
+
= 36V
V
SENSE
= 0mV, V
S+
= 44V, V
+
= 36V
V
SENSE
= 120mV, A
V
= 100, R
OUT
= 10k
Guaranteed by V
O(MAX)
V
S+
= 44V, V
S–
= 0V, R
OUT
= 0Ω
V
SENSE
= 50mV, A
V
= 10V/V
V
SENSE
= 5mV to 100mV
V
SENSE
= 5mV to 150mV, A
V
= 50V/V, R
IN
= 400Ω
I
(+IN) +
I
(–IN)
= –5mA
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
MIN
–0.3
–0.3
–1
–1.4
–3
–0.3
–0.65
–0.4
–0.75
–1
–1.4
100
95
94
90
2.85
98
94
98
94
TYP
MAX
44
44
UNITS
V
V
%
%
%
mV
mV
mV
mV
mV
mV
μV/°C
dB
dB
dB
dB
0.1
1
1.4
3
V
SENSE
= 5mV
V
SENSE
= 5mV
V
SENSE
= 5mV, V
S+
= 0V
–0.1
–0.1
–0.3
0.5
120
0.3
0.65
0.4
0.75
1
1.4
36
120
120
16
–0.05
0.08
0.01
0.035
200
250
1.27
27
0.6
1
325
375
40
1.6
V
dB
dB
dB
dB
μA
μA
μA
μA
μA
μA
μA
mV
V
mA
mA
1
1.5
100
5
3
1.75
–9.5
2
–12
kHz
μs
μs
V/μs
V
Output Settling to 1% of Final Value V
SENSE
= 5mV to 100mV
6105fa
4
LT6105
ELECTRICAL CHARACTERISTICS
SYMBOL
V
S+
, V
S–
A
V
Error
PARAMETER
Input Voltage Range
Voltage Gain Error (Note 6)
The
l
denotes the specifications which apply over the temperature range
–40°C < T
A
< 125°C (LT6105H), otherwise specifications are at T
A
= 25°C. V
+
= 12V, V
–
= 0V, V
S+
= 12V (see Figure 1), R
IN1
= R
IN2
=
100Ω, R
OUT
= 5k (A
V
= 50), V
SENSE
= V
S+
– V
S–
, unless otherwise specified. (Note 5)
CONDITIONS
Guaranteed by CMRR
V
SENSE
= 25mV to 75mV, V
S+
= 12V
V
SENSE
= 25mV to 75mV, V
S+
= 0V
V
OS
Input Offset Voltage
MS8 Package
Input Offset Voltage
DCB Package
Input Offset Voltage
ΔV
OS
/ΔT
CMRR
Temperature Coefficient of V
OS
Input Common Mode
Rejection Ratio
V
SENSE
= 5mV, V
S+
= 2.8V to 44V
V
SENSE
= 5mV, V
S+
= –0.3V to 44V
V
SENSE
= 5mV, V
S+
= –0.1V to 44V
V
+
PSRR
Power Supply Voltage Range
Power Supply Rejection Ratio
Guaranteed by PSRR
V
SENSE
= 5mV, V
S+
= 12V, V
+
= 2.85V to 36V
V
SENSE
= 5mV, V
S+
= 0V, V
+
= 2.85V to 36V
I
(+IN)
, I
(–IN)
I
(+IN)
– I
(–IN)
I
(+IN) +
I
(–IN)
I
S
V
O(MIN)
V
O(MAX)
I
OUT
I
SC
BW
t
S
t
r
SR
V
REV
Input Current
Input Offset Current
Input Current (Power-Down)
V
+
Supply Current
Minimum Output Voltage
Output High (Referred to V
+
)
Maximum Output Current
Short-Circuit Output Current
–3dB Bandwidth
Input Step Response (Note 7)
Slew Rate (Note 8)
Reverse Input Voltage
(Referred to V
–
)
V
SENSE
= 0V, V
S+
= 3V
V
SENSE
= 0V, V
S+
= 0V
V
SENSE
= 0V, V
S+
= 3V
V
SENSE
= 0V, V
S+
= 0V
V
+
= 0V, V
S+
= 44V, V
SENSE
= 0V
V
SENSE
= 0V, V
S+
= 3V, V
+
= 2.85V
V
SENSE
= 0V, V
S+
= 3V, V
+
= 36V
V
SENSE
= 0mV, V
S+
= 44V, V
+
= 36V
V
SENSE
= 120mV, A
V
= 100, R
OUT
= 10k
Guaranteed by V
O(MAX)
V
S+
= 44V, V
S–
= 0V, R
OUT
= 0Ω
V
SENSE
= 50mV, A
V
= 10V/V
V
SENSE
= 5mV to 100mV
V
SENSE
= 5mV to 150mV, A
V
= 50V/V, R
IN
= 400Ω
I
(+IN) +
I
(–IN)
= –5mA
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
MIN
–0.3
–0.1
–1
–1.5
–3.25
–0.3
–0.8
–0.4
–0.9
–1
–1.6
100
95
94
80
2.85
98
94
98
94
TYP
MAX
44
44
UNITS
V
V
%
%
%
mV
mV
mV
mV
mV
mV
μV/°C
dB
dB
dB
dB
0.1
1
1.5
3.25
V
SENSE
= 5mV
V
SENSE
= 5mV
V
SENSE
= 5mV, V
S+
= 0V
–0.1
–0.1
–0.3
0.5
120
0.3
0.8
0.4
0.9
1
1.6
36
120
120
18
–0.05
0.35
0.1
0.5
240
300
1.3
30
0.8
2.5
350
450
45
1.7
V
dB
dB
dB
dB
μA
μA
μA
μA
μA
μA
μA
mV
V
mA
mA
1
1.5
100
5
3
1.75
–9.5
2
–12
kHz
μs
μs
V/μs
V
Output Settling to 1% of Final Value V
SENSE
= 5mV to 100mV
6105fa
5
嵌入式系统
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