LINER LT6100HMS8 Precision, gain selectable high side current sense amplifier Datasheet

LT6100
Precision, Gain Selectable
High Side Current Sense
Amplifier
DESCRIPTIO
U
FEATURES
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Input Offset Voltage: 300µV (Max)
Sense Inputs Up to 48V
0.5% Gain Accuracy
Pin Selectable Gain: 10, 12.5, 20, 25, 40, 50V/V
Separate Power Supply: 2.7V to 36V
Operating Current: 60µA
Sense Input Current (VCC Powered Down): 1nA
Reverse Battery Protected to – 48V
Buffered Output
Noise Filtering Input
–40°C to 125°C Operating Temperature Range
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.
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.
U
APPLICATIO S
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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.
Battery Monitoring
Fuse Monitoring
Portable and Cellular Phones
Portable Test/Measurement Systems
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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
U
TYPICAL APPLICATIO
Input Offset Voltage
vs VS Sense Input Voltage
0A to 33A High Side Current Monitor with 12kHz Frequency Rolloff
1.5
3V
2
LT6100
VCC
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
VSENSE = 100mV
VCC = 3V
TA = 25°C
1.0
0.5
0
–0.5
–1.0
6100 TA01a
–1.5
220pF
0
5
10 15 20 25 30 35 40 45 50
VS SENSE INPUT VOLTAGE (V)
6100 TA01b
6100f
1
LT6100
W W
W
AXI U
U
ABSOLUTE
RATI GS
(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 ............................................. – 40°C to 85°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
U
U
W
PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
TOP VIEW
VS – 1
VCC 2
FIL 3
8
9
VEE 4
VS+
7
A4
6
A2
5
VOUT
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
ORDER PART
NUMBER
TOP VIEW
LT6100CDD
LT6100IDD
LT6100HDD
DD PART MARKING*
TJMAX = 125°C, θJA = 43°C/ W
EXPOSED PAD (PIN 9) IS VEE
MUST BE SOLDERED TO PCB
VS– 1
VCC 2
FIL 3
VEE 4
8
7
6
5
LT6100CMS8
LT6100IMS8
LT6100HMS8
VS+
A4
A2
VOUT
MS8 PACKAGE
8-LEAD PLASTIC MSOP
MS PART MARKING*
TJMAX = 150°C, θJA = 250°C/ W
LBMW
LTBMV
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grades are identified by a label on the shipping container.
ELECTRICAL CHARACTERISTICS
The ● 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+
VSENSE
Sense Amplifier Supply Voltage
Input Sense Voltage Full Scale
VOS
Input Offset Voltage (MS Package)
Single Supply Operation (VCC = 2.7V)
VSENSE = VS+ – VS–, VCC = 3V, AV = 10V/V
VSENSE = VS+ – VS–, VCC = 5V, AV = 10V/V
IOUT = 0, VCC = 5V
Input Offset Voltage (DD Package)
IOUT = 0, VCC = 5V
VOS TC
Temperature Coefficient of VOS
VCC = 5V (Note 6)
AV
Gain, VOUT/VSENSE
VSENSE = 50mV to 80mV, VCC Supply = 5V, AV = 10V/V
LT6100DD8
MIN
●
●
●
Output Voltage Gain Error (Note 7)
UNITS
48
V
mV
mV
µV
µV
µV
µV
µV/°C
0.5
10
10
10
10
10.05
10.06
10.10
10.10
V/V
V/V
V/V
V/V
–0.5
0.5
%
●
–0.6
–1.0
0.6
1.0
%
%
●
–1.0
1.0
●
●
●
VSENSE = 50mV to 80mV, VCC Supply = 5V,
AV = 10, 12.5, 20, 25, 40, 50V/V
LT6100DD8
VS = 48V
±80
MAX
300
500
350
550
3
●
●
VS = 48V
4.1
110
300
–300
–500
–350
–550
TYP
9.95
9.94
9.90
9.9
±80
%
6100f
2
LT6100
ELECTRICAL CHARACTERISTICS
The ● 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
MIN
TYP
VS CMRR
VS Sense Input Common Mode
Rejection Ratio
VSENSE = 50mV, VCC = 2.7V, VS = 4.1V to 36V
●
105
100
120
120
dB
dB
VCC Supply Rejection Ratio
VSENSE = 50mV, VS = 36V, VCC = 3V to 30V
●
105
100
120
120
dB
dB
VCC PSRR
2.7
MAX
VCC
Supply Voltage VCC
BW
Bandwidth
AV = 10V/V, fO = –3dB
AV = 50V/V, fO = –3dB
tS
Output Settling to 1% Final Value
VSENSE = 10mV to 100mV
IS+(O), IS–(O)
Sense Input Current
VSENSE = 0V
●
4.5
10
µA
ICC(O)
VCC Supply Current
VSENSE = 0V, VCC = 5V
●
60
130
µA
SR
Slew Rate
VCC = 15V, VSENSE = 50mV to 300mV, AV = 50V/V
100
20
●
0.03
0.02
36
UNITS
V
150
50
kHz
kHz
15
µs
0.05
0.05
V/µs
V/µs
8
15
mA
50
60
V
Short-Circuit Current
ISC+, ISC–
Reverse VS Supply
IS = –100µA
●
VO(MIN)
Minimum Output Voltage
VSENSE = 0V, No Load
VSENSE = VS+ – VS– = –100mV, AV = 50V/V, No Load
●
15
15
30
25
mV
mV
VO(MAX)
Output High
VCC = 5V, AV = 50V/V, VSENSE = 100mV, IL = 0
VSENSE = 100mV, IL = 100µA
VSENSE = 100mV, IL = 500µA
VSENSE = 100mV, IL = 1mA
●
●
●
●
75
85
125
175
125
150
250
400
mV
mV
mV
mV
●
0.001
1
µA
ISC
IS+, IS– (Off) Sense Input Current (Power Down) VCC = 0V, VS = 48V, VSENSE = 0V
The ● 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
VS–, VS+
Sense Amplifier Supply Voltage
Single Supply Operation (VCC = 2.7V)
●
4.1
VSENSE
Input Sense Voltage Full Scale
VSENSE = VS+ – VS–, VCC = 3V, AV = 10V/V
VSENSE = VS+ – VS–, VCC = 5V, AV = 10V/V
●
●
110
300
VOS
Input Offset Voltage (MS Package)
IOUT = 0, VCC = 5V
–300
–550
±80
●
300
550
µV
µV
–350
–600
±80
●
350
600
µV
µV
Input Offset Voltage (DD Package)
CONDITIONS
MIN
IOUT = 0, VCC = 5V
VOS TC
Temperature Coefficient of VOS
VCC = 5V (Note 6)
AV
Gain, VOUT/VSENSE
VSENSE = 50mV to 80mV, VCC = 5V, AV = 10V/V
LT6100DD8
●
●
Output Voltage Gain Error (Note 7)
VS = 48V
VSENSE = 50mV to 80mV, VCC = 5V,
AV = 10, 12.5, 20, 25, 40, 50V/V
LT6100DD8
VS = 48V
●
TYP
MAX
48
UNITS
V
mV
mV
µV/°C
0.5
3
9.95
9.94
9.90
10
10
10
10.05
10.06
10.10
V/V
V/V
V/V
9.9
–0.5
10
10.10
0.5
V/V
%
●
–0.6
–1.0
0.6
1.0
%
%
●
–1.0
1.0
%
6100f
3
LT6100
ELECTRICAL CHARACTERISTICS
The ● 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
MIN
TYP
VS CMRR
VS Sense Input Common Mode
Rejection Ratio
VSENSE = 50mV, VCC = 2.7V, VS = 4.1V to 36V
●
105
100
120
120
dB
dB
VCC Supply Rejection Ratio
VSENSE = 50mV, VS = 36V, VCC = 3V to 30V
●
105
100
120
120
dB
dB
VCC PSRR
2.7
MAX
UNITS
VCC
Supply Voltage VCC
BW
Bandwidth
AV = 10V/V, fO = –3dB
AV = 50V/V, fO = –3dB
tS
Output Settling to 1% Final Value
VSENSE = 10mV to 100mV
IS+(O), IS–(O)
Sense Input Current
VSENSE = 0V
●
4.5
10
µA
ICC(O)
Supply Current
VSENSE = 0V, V+ Supply = 5V
●
60
145
µA
SR
Slew Rate
VCC = 15V, VSENSE = 50mV to 300mV, AV = 50V/V
100
20
●
0.03
0.02
36
V
150
50
kHz
kHz
15
µs
0.05
0.05
V/µs
V/µs
8
15
mA
50
60
V
Short-Circuit Current
ISC+, ISC–
Reverse VS Supply
IS = –100µA
●
VO(MIN)
Minimum Output Voltage
VSENSE = 0V, No Load
VSENSE = VS+ – VS– = –100mV, AV = 50V/V, No Load
●
15
15
30
25
mV
mV
VO(MAX)
Output High
VCC = 5V, AV = 50V/V, VSENSE = 100mV, IL = 0
VSENSE = 100mV, IL = 100µA
VSENSE = 100mV, IL = 500µA
VSENSE = 100mV, IL = 1mA
●
●
●
●
75
85
125
175
125
150
250
400
mV
mV
mV
mV
●
0.001
1
µA
ISC
IS+, IS– (Off) Sense Input Current (Power Down) VCC = 0V, VS = 48V, VSENSE = 0V
The ● 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
Single Supply Operation (VCC = 2.7V)
VSENSE
Input Sense Voltage Full Scale
VSENSE = VS – VS–, VCC = 3V, AV
VSENSE = VS+ – VS–, VCC = 5V, AV
VOS
Input Offset Voltage (MS Package)
IOUT = 0, VCC = 5V
Input Offset Voltage (DD Package)
+
MIN
= 10V/V
= 10V/V
Temperature Coefficient of VOS
VCC = 5V (Note 6)
AV
Gain, VOUT/VSENSE
VSENSE = 50mV to 80mV, VCC = 5V, AV = 10V/V
LT6100DD8
Output Voltage Gain Error (Note 7)
110
300
–300
–600
±80
●
300
600
µV
µV
–350
–650
±80
●
350
650
µV
µV
0.5
5
10
10
10
10
10.05
10.06
10.10
10.10
V/V
V/V
V/V
V/V
–0.5
0.5
%
–0.6
–1.0
–1.0
0.6
1.0
1.0
%
%
%
●
●
VSENSE = 50mV to 80mV, VCC = 5V,
AV = 10, 12.5, 20, 25, 40, 50V/V
LT6100DD8
●
VS = 48V
UNITS
●
●
●
VS = 48V
MAX
4.1
IOUT = 0, VCC = 5V
VOS TC
TYP
●
●
9.95
9.94
9.90
9.9
48
V
mV
mV
µV/°C
6100f
4
LT6100
ELECTRICAL CHARACTERISTICS
The ● 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
MIN
TYP
VS CMRR
VS Sense Input Common Mode
Rejection Ratio
VSENSE = 50mV, VCC = 2.7V, VS = 4.1V to 36V
●
105
100
120
120
dB
dB
VCC Supply Rejection Ratio
VSENSE = 50mV, VS = 36V, VCC = 3V to 30V
●
105
95
120
120
dB
dB
VCC PSRR
2.7
MAX
VCC
Supply Voltage VCC
BW
Bandwidth
AV = 10V/V, fO = –3dB
AV = 50V/V, fO = –3dB
tS
Output Settling to 1% Final Value
VSENSE = 10mV to 100mV
IS+(O), IS–(O)
Sense Input Current
VSENSE = 0V
●
4.5
10
µA
ICC(O)
Supply Current
VSENSE = 0V, VCC = 5V
●
60
170
µA
SR
Slew Rate
VCC = 15V, VSENSE = 50mV to 300mV, AV = 50V/V
100
20
●
0.03
0.02
36
UNITS
V
150
50
kHz
kHz
15
µs
0.05
0.05
V/µs
V/µs
8
15
mA
50
60
V
Short-Circuit Current
ISC+, ISC–
Reverse VS Supply
IS = –100µA
●
VO(MIN)
Minimum Output Voltage
VSENSE = 0V, No Load
VSENSE = VS+ – VS– = –100mV, AV = 50V/V, No Load
●
15
15
35
25
mV
mV
VO(MAX)
Output High
VCC = 5V, AV = 50V/V, VSENSE = 100mV, IL = 0
VSENSE = 100mV, IL = 100µA
VSENSE = 100mV, IL = 500µA
VSENSE = 100mV, IL = 1mA
●
●
●
●
75
85
125
175
140
160
250
400
mV
mV
mV
mV
●
0.001
1
µA
ISC
IS+, IS– (Off) Sense Input Current (Power Down) VCC = 0V, VS = 48V, VSENSE = 0V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
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.
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 other gain
error test.
6100f
5
LT6100
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Input Offset Voltage
vs VS+ Input Voltage
1.5
400
100
0
–100
–200
TA = 25°C
0
–0.5
TA = 125°C
TA = 85°C
–1.0
–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
10
1.2
1.0
0.8
0.6
40
30
20
5
10 15 20 25 30
VCC SUPPLY VOLTAGE (V)
35
VS+ = 6.4V TO 48V
VCC = 5V
TA = –40°C TO 125°C
Gain vs Temperature
TA = –40°C
VS > 6.6V
7 TYPICAL UNITS
VSENSE = 50mV TO 80mV
VS+ = 6.4V TO 48V
VCC = 5V
AV = 50V/V
50.04
50.02
2.5
TA = –40°C
VS = 6.4V
2.0
1.5
40
6100 G02
50.06
50.00
49.98
49.96
49.94
1.0
49.92
0.5
0.2
0
–150
49.90
0
–90
–30
30
90
SENSE VOLTAGE (VS+ – VS–)(mV)
0
150
300
180
240
120
60
SENSE VOLTAGE (VS+ – VS–) (mV)
10
8
TA = 125°C
TA = 85°C
4
TA = 25°C
TA = –40°C
2
35
POSITIVE SENSE INPUT CURRENT (µA)
VS+ = 4.4V TO 48V
VCC = 3V
6
30
30
70
110
–70 –30
SENSE VOLTAGE (VS+ – VS–) (mV)
6100 G06
Output Positive Swing
vs Load Current
350
VS+ = 4.4V TO 48V
VCC = 3V
TA = 125°C
25
TA = 85°C
20
TA = 25°C
15
TA = –40°C
10
5
0
–5
–110
6100 G05
Positive Sense Input Current
vs Sense Voltage
Negative Sense Input Current
vs Sense Voltage
12
49.88
–40 –25 –10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
6100 G04
6100 G03
NEGATIVE SENSE INPUT CURRENT (µA)
0
50
0.4
0
TA = 125°C
Output Voltage vs Sense Voltage
3.0
TA = –40°C
VS = 4.4V
100
6100 G01
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
1.4
VSENSE = 100mV
VS+ = 48V
150
VS+ INPUT VOLTAGE (V)
3.5
VS+ = 4.4V TO 48V
VCC = 3V
AV = 10V/V
TA = –40°C TO 125°C TA = –40°C
VS > 4.6V
TA = –40°C
200
0
0
Output Voltage vs Sense Voltage
1.6
TA = 25°C
250
50
6100 G21
1.8
TA = 85°C
300
GAIN (V/V)
200
TA = –40°C
0.5
–110
110
–70 –30
30
70
SENSE VOLTAGE (VS+ – VS–) (mV)
6100 G07
OUTPUT POSITIVE SWING (mV)
INPUT OFFSET VOLTAGE (µV)
300
350
VSENSE = 100mV
VCC = 3V
1.0
INPUT OFFSET VOLTAGE (mV)
9 TYPICAL UNITS
VS = 6.4V
VCC = 5V
Input Offset Voltage
vs VCC Supply Voltage
INPUT OFFSET VOLTAGE (µV)
Input Offset Voltage
vs Temperature
VS+ = 6.4V
VCC = 5V
VSENSE = 150mV
AV = 50V/V
300
250
TA = 125°C
TA = 85°C
200
150
TA = 25°C
100
TA = –40°C
50
0
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
LOAD CURRENT (mA)
6100 G08
6100f
6
LT6100
U W
TYPICAL PERFOR A CE CHARACTERISTICS
VCC Supply Current vs
VS Input Voltage
Op Amp Output Impedance
vs Frequency
10k
VSENSE = 0V
180 VCC = 3V
TA = 125°C
140
OUTPUT IMPEDANCE (Ω)
VCC SUPPLY CURRENT (µA)
160
TA = 85°C
120
TA = 25°C
100
TA = –40°C
80
60
1k
Gain vs Frequency
50
VS+, VS– = 6.5V
VCC = 5V
VEE = –5V
FIL = 0V
40
G2 = 5V/V
G2 = 2V/V
10
1
0
–10
–30
20
–40
0
0
10
30
40
20
TOTAL VS INPUT VOLTAGE (V)
0.1
50
10k
1k
100k
120
90
70
50
40
30
20
10
0
100
1k
10k
FREQUENCY (Hz)
100k
1M
0
GAIN ERROR (%)
VCC PSRR (dB)
60
VS+ = VS–
10
100 1k
10k 100k
FREQUENCY (Hz)
0
1M
50
100
150
200
VSENSE (mV)
6100 G12
250
300
6100 G24
Step Response at VSENSE = 0V to
130mV
130mV
TA = 125°C
VS+ = 6.4V
VCC = 5V
AV = 10V/V
TA = 25°C
–3
1
6100 G11
10
–1
–2
–10
0.1
Sense Input Current (VCC Powered
Down) vs VS+
10M
Gain Error vs VSENSE
110
80
1M
1
VS = 10V
VSENSE = 100mV
VCC = 5V
130
100
10k
100k
FREQUENCY (Hz)
6100 G10
VCC PSRR vs Frequency
150
VS = 6.4V
VCC = 5V
10
1k
6100 G23
CMRR vs Frequency
140
–50
100
1M
FREQUENCY (Hz)
6100 G09
CMRR (dB)
10
–20
G2 = 1V/V
40
TOTAL INPUT CURRENT (IS+ + IS– ) (nA)
AV = 10
20
100
VS = 12.1V
VCC = 10V
AV = 50
30
GAIN (dB)
200
Step Response at VSENSE = 0V to
130mV
130mV
VSENSE
0V
VSENSE
1
0V
6.5V
TA = 85°C
1.3V
0.1
VOUT
VOUT
0V
TA = 25°C
0.01
VS = 10V
AV = 10V/V
CL = 0pF
TA = –40°C
0.001
0
10
20
30
VS+ (V)
40
0V
50µs/DIV
6100 G13
VS = 10V
AV = 50V/V
CL = 0pF
0.2ms/DIV
6100 G14
50
6100 G25
6100f
7
LT6100
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Step Response at VSENSE = 0V to
10mV
Step Response at VSENSE = 0V to
130mV
Step Response at VSENSE = 0V to
10mV
130mV
20mV
VSENSE
20mV
VSENSE
0V
VSENSE
0V
0V
1.3V
500mV
100mV
VOUT
VOUT
0V
VOUT
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
130mV
VSENSE
0V
VS = 10V
AV = 10V/V
COUT = 1000pF
50µs/DIV
6100 G17
Step Response at VSENSE = 0V to
10mV
20mV
VSENSE
0V
6.5V
100mV
VOUT
VOUT
0V
0V
VS = 10V
AV = 50V/V
CL = 1000pF
0.2ms/DIV
6100 G18
VS = 10V
AV = 10V/V
CL = 1000pF
Step Response at VSENSE = 0V to
10mV
20mV
VSENSE
0V
50µs/DIV
6100 G19
Start-Up Delay
VS+
500mV
10V
0V
1V
VOUT
VOUT
0V
0V
VS = 10V
AV = 50V/V
CL = 1000pF
50µs/DIV
6100 G20
VCC = 5V
20µs/DIV
VSENSE = 100mV
AV = 10V/V
VEE = 0V
6100 G22
6100f
8
LT6100
U
U
U
PI FU CTIO S
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 RG2 = 5k.
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.
VCC (Pin 2): Supply Voltage Input. This power supply pin
supplies current to both current sense amplifier and op
amp.
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 RG1 = 5k.
VS+ remains functional for voltages up to 48V.
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.
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.
W
FU CTIO AL DIAGRA
U
RSENSE
VIN
(VCC + 1.4V) TO 48V
LOAD
1
8
VS–
VS+
RG1
5k
RG2
5k
+
–
R
25k
A1
VCC
2.7V TO 36V
–
2
Q1 RE
10k
+
VO1
RO
50k
R
VEE
4
FIL
3
VOUT
5
R/3
A4
A2
6
A2
7
6100 F01
Figure 1. Functional Diagram
6100f
9
U
LT6100
U
W
U U
APPLICATIO S I FOR ATIO
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.
6100f
10
LT6100
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APPLICATIO S I FOR ATIO
Noise Filtering
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 0.75V of VCC or a maximum of
36V, a limit set by internal junction breakdown. Within
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
1
0
+
VS
2
+
–1.0
5V
–1.5
3
–2.0
VS
VCC
C2
0.1µF
A4
–
–0.5
C1
0.1µF
8
–
DC
SOURCE
7
+
INPUT OFFSET VOLTAGE (mV)
these constraints, an amplified, level shifted representation of the RSENSE voltage is developed at VOUT. The output
is well behaved driving capacitive loads to 1000pF.
FIL
A2
6
–2.5
–3.0
4
–3.5
0
10
40
30
20
VS INPUT VOLTAGE (V)
50
OUT
VEE
5
OUTPUT
LT6100
6100 F03
6100 F02
Figure 2. VOS vs VS Input Voltage
Figure 3. Current Monitoring of a Fuse Protected Circuit
6100f
11
LT6100
U
W
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APPLICATIO S I FOR ATIO
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 V SENSE
= 0V, the LT6100’s buffered output can only swing as low
as 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).
1.6
TO LOAD
RSENSE
–
+
VS
+
A4
–
3
5V
VS
VCC
C2
0.1µF
3V
+
7
+
2
C1
0.1µF
8
FIL
A2
6
OUTPUT VOLTAGE (V)
1
VS = 4.4V TO 48V
VCC = 3V
AV = 10V/V
TA = 25°C
1.4
1.2
1.0
0.8
0.6
0.4
0.2
4
OUT
VEE
5
0
OUTPUT
LT6100
0
30
60
120
90
SENSE VOLTAGE (VS+ – VS–) (mV)
6100 F04
6100 F05
Figure 5. Output Voltage vs VSENSE
Figure 4. LT6100 Load Current Monitor
0.40
0.30
1.4
0.25
0.20
0.15
0.10
1.2
1.0
0.8
0.6
0.4
0.05
0
VS = 4.4V TO 48V
VCC = 3V
AV = 50V/V
TA = 25°C
1.6
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
1.8
VS = 4.4V TO 48V
VCC = 3V
AV = 10V/V
TA = 25°C
0.35
150
0.2
0
5
10
20
25
15
SENSE VOLTAGE (VS+ – VS–) (mV)
30
6100 F06
Figure 6. Expanded View of Output Voltage vs VSENSE, AV = 10V/V
0
0
10
15
5
20
25
SENSE VOLTAGE (VS+ – VS–) (mV)
30
6100 F07
Figure 7. Expanded View of Output Voltage vs VSENSE,
AV = 50V/V
6100f
12
LT6100
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APPLICATIO S I FOR ATIO
Power Down While Connected to a Battery
This is due to the implementation of Linear Technology’s
Over-The-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, its inputs remain high impedance (see Figure 8).
Over-The-Top is a registered trademark of Linear Technology Corporation.
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
U
TYPICAL APPLICATIO
Adjust Gain Dynamically for Enhanced Range
VDR+
ISENSE
RSENSE
TO LOAD
FROM SOURCE
VS+
10Ω
1%
VS–
IHOTPLATE
–
+
VCC
5V
FIL
VCC
VEE
MICRO-HOTPLATE
BOSTON
MICROSYSTEMS
MHP100S-005
VOUT
VEE
A2
A4
6100 TA05
2N7002
0V
(GAIN = 10)
5V
5V
(GAIN = 50)
VS+
+ –
–
LT6100 VS
5V
Micro-Hotplate Voltage and Current Monitor
LT6100
A2 A4
5V
M9
M3
M1
LT1991
P1
P3
P9
VDR–
CURRENT
MONITOR
VOUT = 500mV/mA
VOLTAGE
MONITOR
V + – VDR–
VOUT = DR
10
6100 TA06
www.bostonmicrosystems.com
6100f
13
LT6100
U
PACKAGE DESCRIPTIO
DD Package
8-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1698)
0.675 ±0.05
3.5 ±0.05
1.65 ±0.05
2.15 ±0.05 (2 SIDES)
PACKAGE
OUTLINE
0.25 ± 0.05
0.50
BSC
2.38 ±0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
R = 0.115
TYP
5
3.00 ±0.10
(4 SIDES)
0.38 ± 0.10
8
1.65 ± 0.10
(2 SIDES)
PIN 1
TOP MARK
(NOTE 6)
(DD8) DFN 1203
0.200 REF
0.75 ±0.05
0.00 – 0.05
4
0.25 ± 0.05
1
0.50 BSC
2.38 ±0.10
(2 SIDES)
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
6100f
14
LT6100
U
PACKAGE DESCRIPTIO
MS8 Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1660)
0.889 ± 0.127
(.035 ± .005)
5.23
(.206)
MIN
3.20 – 3.45
(.126 – .136)
0.42 ± 0.038
(.0165 ± .0015)
TYP
3.00 ± 0.102
(.118 ± .004)
(NOTE 3)
0.65
(.0256)
BSC
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
0.127 ± 0.076
(.005 ± .003)
MSOP (MS8) 0204
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
6100f
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.
15
LT6100
U
TYPICAL APPLICATIO
800mA/1A White LED Current Regulator
D2
LED
L1
3µH
VIN
3.3V TO 4.2V
SINGLE Li-Ion
VIN
LED
CURRENT
WARNING! VERY BRIGHT
DO NOT OBSERVE DIRECTLY
D1
B130
0.030Ω
GND
22µF
16V
CER
1210
124k
VC
+ –
VOUT
VEE
MMBT2222
A4
OPEN: 1A
CLOSED: 800mA
4.99k
6100 TA02
Filtered Gain of 20 Current Sense
ISENSE
RSENSE
+
LT6100 VS
VS–
+
LT6100 VS
LOAD
VS–
+
VCC
5V
FIL
LOAD
VCC
FIL
VOUT
20 • RSENSE • ISENSE
1000pF
VEE
RSENSE
VSUPPLY
6.4V TO 48V
–
+
3V
Gain of 50 Current Sense
–
ISENSE
A2
0.1µF
8.2k
D1: DIODES INC.
D2: LUMILEDS LXML-PW09 WHITE EMITTER
L1: SUMIDA CDRH6D28-3R0
VSUPPLY
4.4V TO 48V
VS–
VCC
FB
SHDN
4.7µF
6.3V
CER
LT6100
VSW
LT3436
LED
ON
VS+
A2
A4
VEE
6100 TA03
A2
VOUT
50 • RSENSE • ISENSE
A4
6100 TA04
–3dB AT 2.6kHz
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC1043
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-TopTM 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
High Voltage, High Side, Precision Current Sense Amplifier
4V to 60V, Gain Configurable, SOT-23
Over-The-Top is a trademark of Linear Technology Corporation.
6100f
16
Linear Technology Corporation
LT/TP 0405 500 • PRINTED IN THE USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2005