1787f Layout
1
LT1787/LT1787HV
1787fb
Precision, High Side
Current Sense Amplifiers
s
Input Offset Voltage: 75
V (Max)
s
60V Supply Operation (LT1787HV)
s
12-Bit Dynamic Range
s
Operating Current: 60
A
s
User-Selectable External Sense Resistor
s
Bidirectional High Side Current Sensing
s
Unidirectional or Bidirectional Output
s
Input Noise Filtering
s
Available in 8-Lead SO and MSOP Packages
s
40
C to 125
C Operating Temperature Range
The LT
1787 is a complete micropower precision high
side current sense amplifier. The LT1787 monitors bidi-
rectional currents via the voltage across an external sense
resistor. A current or voltage output indicates the direction
and magnitude of the sense current. The LT1787 delivers
greater than a 12-bit dynamic range with ultralow 40
V
input offset voltage compared to a typical 250mV full-
scale input voltage. A fixed gain of 8 is set by onboard
precision resistors. Input signal filtering is easily imple-
mented with a capacitor between the FIL
and FIL
+
pins.
The LT1787HV operates from 2.5V to 60V total supply
voltage and the LT1787 operates from 2.5V to 36V total
supply voltage. Both versions have a PSRR in excess of
120dB. The LT1787/LT1787HV draw only 60
A and are
available in 8-lead SO and MSOP packages.
s
Battery Monitoring
s
Power Monitoring
s
Portable Phones
s
Cellular Phones
s
Portable Test/Measurement Systems
s
Battery-Operated Systems
, LTC and LT are registered trademarks of Linear Technology Corporation.
Input Offset Voltage vs Supply Voltage
12-Bit Dynamic Resolution Unidirectional Output into LTC
1286 ADC
TOTAL SUPPLY VOLTAGE (V)
0
INPUT OFFSET VOLTAGE (
V)
10
20
30
40
1787 TA01b
50
50
40
30
20
10
0
10
20
30
40
50
60
1
8
2
7
3
6
4
5
LT1787HV
R
SENSE
0.0016
1787 TA01
C1
1
F
5V
FIL
+
FIL
R1
15k
C2
0.1
F
V
OUT
= V
BIAS
+ (8 I
LOAD
R
SENSE
)
I = 100A
2.5V TO 60V
TO
LOAD
LT1634-1.25
TO
P
V
REF
V
CC
GND
LTC1286
CS
CLK
D
OUT
+IN
IN
V
BIAS
V
OUT
R
OUT
20k
V
S
V
S
+
DNC
V
EE
APPLICATIO S
U
FEATURES
TYPICAL APPLICATIO
U
DESCRIPTIO
U
2
LT1787/LT1787HV
1787fb
ABSOLUTE
M
AXI
M
U
M
RATINGS
W
W
W
U
Differential Sense Voltage ......................................
10V
Total Supply Voltage (LT1787) ................................ 40V
Total Supply Voltage (LT1787HV) ........................... 65V
Output Voltage ..................... (V
EE
0.3V) to (V
EE
+ 35V)
Output Bias Voltage ............. (V
EE
0.3V) to (V
EE
+ 35V)
Operating Temperature Range (Note 3)
LT1787C ............................................. 40
C to 85
C
LT1787I .............................................. 40
C to 85
C
LT1787H .......................................... 40
C to 125
C
(Notes 1, 2)
PACKAGE/ORDER I
N
FOR
M
ATIO
N
W
U
U
ORDER PART NUMBER
LT1787CS8
LT1787IS8
LT1787HS8
LT1787HVCS8
LT1787HVIS8
LT1787HVHS8
S8 PART MARKING
1787
1787I
1787H
TOP VIEW
FIL
+
V
S
+
V
BIAS
V
OUT
FIL
V
S
DNC*
V
EE
S8 PACKAGE
8-LEAD PLASTIC SO
1
2
3
4
8
7
6
5
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
S
, V
S
+
Sense Amplifier Supply Voltage Single Supply Operation (LT1787)
q
2.5
36
V
Single Supply Operation (LT1787HV)
q
2.5
60
V
V
SENSE
Input Sense Voltage Full Scale
V
SENSE
= V
S
+
V
S
, V
S
= 10V, V
BIAS
= 5V, A
V
= 8
10%
q
500
mV
V
OS
Input Offset Voltage (S8)
I
OUT
= 0, V
S
Supply = 5V
75
40
75
V
0
C
T
A
70
C
q
135
135
V
I
OUT
= 0 (LT1787)
100
100
V
0
C
T
A
70
C
q
160
160
V
I
OUT
= 0 (LT1787HV)
100
100
V
0
C
T
A
70
C
q
160
160
V
Input Offset Voltage (MS8)
I
OUT
= 0, V
S
Supply = 5V
125
40
125
V
0
C
T
A
70
C
q
230
230
V
I
OUT
= 0 (LT1787)
150
150
V
0
C
T
A
70
C
q
250
250
V
I
OUT
= 0 (LT1787HV)
150
150
V
0
C
T
A
70
C
q
250
250
V
The
q
denotes the specifications which apply over the temperature range 0
C
T
A
70
C, otherwise specifications are at T
A
= 25
C.
Total supply = (V
S
V
EE
) = 2.5V to 36V (LT1787C), 2.5V to 60V (LT1787HVC) unless otherwise specified.
* DO NOT CONNECT
T
JMAX
= 150
C,
JA
= 190
C/ W
1
2
3
4
8
7
6
5
TOP VIEW
MS8 PACKAGE
8-LEAD PLASTIC MSOP
FIL
+
V
S
+
V
BIAS
V
OUT
FIL
V
S
DNC*
V
EE
Specified Temperature Range (Note 4)
LT1787C ............................................. 40
C to 85
C
LT1787I .............................................. 40
C to 85
C
LT1787H .......................................... 40
C to 125
C
Storage Temperature Range ..................65
C to 150
C
Lead Temperature (Soldering, 10 sec).................. 300
C
* DO NOT CONNECT
T
JMAX
= 150
C,
JA
= 250
C/ W
ORDER PART NUMBER
LT1787CMS8
LT1787IMS8
LT1787HVCMS8
LT1787HVIMS8
MS8 PART MARKING
(Note 5)
LTGM
LTGN
LTKJ
LTKK
Consult factory for parts specified with wider operating temperature ranges.
1787HV
787HVI
787HVH
3
LT1787/LT1787HV
1787fb
V
OS
TC
Temperature Coefficient of V
OS
V
S
Supply = 5V (Note 6)
q
0.5
2
V/
C
I
OUT(O)
No-Load Output Current Error
V
SENSE
= 0V
4
nA
V
OUT(O)
No-Load Output Voltage Error
V
SENSE
= 0V, V
S
Supply = 5V
600
600
V
(S8)
0
C
T
A
70
C
q
1080
1080
V
No-Load Output Voltage Error
V
SENSE
= 0V, V
S
Supply = 5V
1000
1000
V
(MS8)
0
C
T
A
70
C
q
1840
1840
V
g
m
Tranconductance, I
OUT
/ V
SENSE
V
SENSE
= 10mV, 50mV, 100mV, 150mV, 250mV,
400
A/V
V
S
Supply = Total Supply + |V
SENSE
|
A
V
Gain, V
OUT
/ V
SENSE
V
SENSE
= 100mV, V
S
Supply = 5V
q
7.76
8
8.24
V/V
Output Voltage Gain Error
V
SENSE
= 100mV, V
S
Supply = 5V
q
3
1
3
%
V
S
PSRR
V
S
Supply Rejection Ratio
V
SENSE
= 0V, V
S
Supply = 2.5V to 36V (LT1787)
q
120
135
dB
V
SENSE
= 0V, V
S
Supply = 2.5V to 60V (LT1787HV)
q
120
135
dB
V
EE
PSRR Negative Supply Rejection Ratio V
SENSE
= 0V, V
S
Supply = 15V, V
BIAS
= 0V,
q
100
130
dB
V
EE
= 1V to 15V (LT1787)
V
SENSE
= 0V, V
S
Supply = 40V, V
BIAS
= 0V,
q
100
130
dB
V
EE
= 1V to 15V (LT1787HV)
V
OS
Change in Input Offset Voltage
V
SENSE
= 0V, V
S
Supply = 36V, V
BIAS
= 0.5V to 25V (LT1787)
q
100
130
dB
V
BIAS
with Change in V
BIAS
Voltage
V
SENSE
= 0V, V
S
Supply = 60V, V
BIAS
= 0.5V to 25V (LT1787HV)
q
100
130
dB
I
S
+
(O)
Positive Input Sense Current
V
SENSE
= 0V
q
10
20
A
I
S
(O)
Negative Input Sense Current
V
SENSE
= 0V
q
50
100
A
I
EE(O)
Negative Supply Current
V
SENSE
= 0V
q
60
120
A
I
OUT
Output Current
V
SENSE
=
128mV
50
A
V
OUT
Output Voltage
V
SENSE
=
128mV, V
S
+
3.3V
V
BIAS
1.024
V
Ripple Rejection
V
S
+
= V
S
= 20V,
V
S
Supply = 1V, f = 1kHz
q
80
88
dB
V
OMIN
Minimum Output Voltage
V
SENSE
= 0V, V
BIAS
= 0V
q
30
45
mV
V
SENSE
= V
S
+
V
S
= 128mV, V
BIAS
= 0V
10
mV
V
SENSE
= 0V, V
BIAS
= 0V
q
30
49
mV
V
SENSE
= V
S
+
V
S
= 128mV, V
BIAS
= 0V
10
mV
Unipolar Output
V
SENSE
= 2mV, V
BIAS
= 0V
32
50
mV
Saturation Voltage
V
SENSE
= 4mV, V
BIAS
= 0V
38
55
mV
V
SENSE
= 5mV, V
BIAS
= 0V
43
60
mV
V
SENSE
= 6mV, V
BIAS
= 0V
49
65
mV
V
SENSE
= 2mV, V
BIAS
= 0V
q
32
54
mV
V
SENSE
= 4mV, V
BIAS
= 0V
q
38
59
mV
V
SENSE
= 5mV, V
BIAS
= 0V
q
43
64
mV
V
SENSE
= 6mV, V
BIAS
= 0V
q
49
69
mV
V
OMAX
Maximum Output Voltage
V
S
+
0.75
V
R
G1A,
R
G2A
Input Gain-Setting Resistor
Pin 1 to Pin 2, Pin 7 to Pin 8
1.25
k
R
OUT
Output Resistor
Pin 5 to Pin 6
20
k
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
The
q
denotes the specifications which apply over the temperature range 0
C
T
A
70
C, otherwise specifications are at T
A
= 25
C.
Total supply = (V
S
V
EE
) = 2.5V to 36V (LT1787C), 2.5V to 60V (LT1787HVC) unless otherwise specified.
(Note 5)
4
LT1787/LT1787HV
1787fb
ELECTRICAL CHARACTERISTICS
The
q
denotes the specifications which apply over the temperature range 40
C
T
A
85
C, otherwise specifications are at
T
A
= 25
C. Total supply = (V
S
V
EE
) = 2.5V to 36V (LT1787I), 2.5V to 60V (LT1787HVI) unless otherwise specified. (Note 5)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
S
, V
S
+
Sense Amplifier Supply Voltage Single Supply Operation (LT1787)
q
2.5
36
V
Single Supply Operation (LT1787HV)
q
2.5
60
V
V
SENSE
Input Sense Voltage Full Scale
V
SENSE
= V
S
+
V
S
, V
S
= 10V, V
BIAS
= 5V, A
V
= 8
10%
q
500
mV
V
OS
Input Offset Voltage (S8)
I
OUT
= 0, V
S
Supply = 5V
75
40
75
V
40
C
T
A
85
C
q
200
200
V
I
OUT
= 0 (LT1787)
100
100
V
40
C
T
A
85
C
q
225
225
V
I
OUT
= 0 (LT1787HV)
100
100
V
40
C
T
A
85
C
q
225
225
V
Input Offset Voltage (MS8)
I
OUT
= 0, V
S
Supply = 5V
125
40
125
V
40
C
T
A
85
C
q
250
250
V
I
OUT
= 0 (LT1787)
150
150
V
40
C
T
A
85
C
q
280
280
V
I
OUT
= 0 (LT1787HV)
150
150
V
40
C
T
A
85
C
q
280
280
V
V
OS
TC
Temperature Coefficient of V
OS
V
S
Supply = 5V (Note 6)
q
0.5
2
V/
C
I
OUT(O)
No-Load Output Current Error
V
SENSE
= 0V
4
nA
V
OUT(O)
No-Load Output Voltage Error
V
SENSE
= 0V, V
S
Supply = 5V
600
600
V
(S8)
40
C
T
A
85
C
q
1600
1600
V
No-Load Output Voltage Error
V
SENSE
= 0V, V
S
Supply = 5V
1000
1000
V
(MS8)
40
C
T
A
85
C
q
2000
2000
V
g
m
Tranconductance, I
OUT
/ V
SENSE
V
SENSE
= 10mV, 50mV, 100mV, 150mV, 250mV,
400
A/V
V
S
Supply = Total Supply + |V
SENSE
|
A
V
Gain, V
OUT
/ V
SENSE
V
SENSE
= 100mV, V
S
Supply = 5V
q
7.76
8
8.24
V/V
Output Voltage Gain Error
V
SENSE
= 100mV, V
S
Supply = 5V
q
3
1
3
%
V
S
PSRR
V
S
Supply Rejection Ratio
V
SENSE
= 0V, V
S
Supply = 2.5V to 36V (LT1787)
q
120
135
dB
V
SENSE
= 0V, V
S
Supply = 2.5V to 60V (LT1787HV)
q
120
135
dB
V
EE
PSRR Negative Supply Rejection Ratio V
SENSE
= 0V, V
S
Supply = 15V, V
BIAS
= 0V,
q
100
130
dB
V
EE
= 1V to 15V (LT1787)
V
SENSE
= 0V, V
S
Supply = 40V, V
BIAS
= 0V,
q
100
130
dB
V
EE
= 1V to 15V (LT1787HV)
V
OS
Change in Input Offset Voltage
V
SENSE
= 0V, V
S
Supply = 36V, V
BIAS
= 0.5V to 25V (LT1787)
q
100
130
dB
V
BIAS
with Change in V
BIAS
Voltage
V
SENSE
= 0V, V
S
Supply = 60V, V
BIAS
= 0.5V to 25V (LT1787HV)
q
100
130
dB
I
S
+
(O)
Positive Input Sense Current
V
SENSE
= 0V
q
10
20
A
I
S
(O)
Negative Input Sense Current
V
SENSE
= 0V
q
50
100
A
I
EE(O)
Negative Supply Current
V
SENSE
= 0V
q
60
120
A
I
OUT
Output Current
V
SENSE
=
128mV
50
A
V
OUT
Output Voltage
V
SENSE
=
128mV, V
S
+
3.3V
V
BIAS
1.024
V
Ripple Rejection
V
S
+
= V
S
= 20V,
V
S
Supply = 1V, f = 1kHz
q
80
88
dB
V
OMIN
Minimum Output Voltage
V
SENSE
= 0V, V
BIAS
= 0V
30
45
mV
V
SENSE
= V
S
+
V
S
= 128mV, V
BIAS
= 0V
10
mV
V
SENSE
= 0V, V
BIAS
= 0V
q
30
51
mV
V
SENSE
= V
S
+
V
S
= 128mV, V
BIAS
= 0V
10
mV
5
LT1787/LT1787HV
1787fb
ELECTRICAL CHARACTERISTICS
The
q
denotes the specifications which apply over the temperature range 40
C
T
A
85
C, otherwise specifications are at
T
A
= 25
C. Total supply = (V
S
V
EE
) = 2.5V to 36V (LT1787I), 2.5V to 60V (LT1787HVI) unless otherwise specified. (Note 5)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Unipolar Output
V
SENSE
= 2mV, V
BIAS
= 0V
32
50
mV
Saturation Voltage
V
SENSE
= 4mV, V
BIAS
= 0V
38
55
mV
V
SENSE
= 5mV, V
BIAS
= 0V
43
60
mV
V
SENSE
= 6mV, V
BIAS
= 0V
49
65
mV
V
SENSE
= 2mV, V
BIAS
= 0V
q
32
56
mV
V
SENSE
= 4mV, V
BIAS
= 0V
q
38
61
mV
V
SENSE
= 5mV, V
BIAS
= 0V
q
43
66
mV
V
SENSE
= 6mV, V
BIAS
= 0V
q
49
71
mV
V
OMAX
Maximum Output Voltage
V
S
+
0.75
V
R
G1A,
R
G2A
Input Gain-Setting Resistor
Pin 1 to Pin 2, Pin 7 to Pin 8
1.25
k
R
OUT
Output Resistor
Pin 5 to Pin 6
20
k
V
S
, V
S
+
Sense Amplifier Supply Voltage Single Supply Operation (LT1787H)
q
2.5
36
V
Single Supply Operation (LT1787HVH)
q
2.5
60
V
V
SENSE
Input Sense Voltage Full Scale
V
SENSE
= V
S
+
V
S
, V
S
= 10V, V
BIAS
= 5V, A
V
= 8
10%
q
500
mV
V
OS
Input Offset Voltage
I
OUT
= 0, V
S
Supply = 5V
75
40
75
V
40
C
T
A
125
C
q
400
400
V
I
OUT
= 0 (LT1787H)
100
100
V
40
C
T
A
125
C
q
550
550
V
I
OUT
= 0 (LT1787HVH)
100
100
V
40
C
T
A
125
C
q
550
550
V
V
OS
TC
Temperature Coefficient of V
OS
V
S
Supply = 5V (Note 6)
q
0.5
4
V/
C
I
OUT(O)
No-Load Output Current Error
V
SENSE
= 0V
4
nA
V
OUT(O)
No-Load Output Voltage Error
V
SENSE
= 0V, V
S
Supply = 5V
600
600
V
40
C
T
A
125
C
q
3200
3200
V
g
m
Tranconductance, I
OUT
/ V
SENSE
V
SENSE
= 10mV, 50mV, 100mV, 150mV, 250mV,
400
A/V
V
S
Supply = Total Supply + |V
SENSE
|
A
V
Gain, V
OUT
/ V
SENSE
V
SENSE
= 100mV, V
S
Supply = 5V
q
7.76
8
8.24
V/V
Output Voltage Gain Error
V
SENSE
= 100mV, V
S
Supply = 5V
q
3
1
3
%
V
S
PSRR
V
S
Supply Rejection Ratio
V
SENSE
= 0V, V
S
Supply = 2.5V to 36V (LT1787H)
q
100
130
dB
V
SENSE
= 0V, V
S
Supply = 2.5V to 60V (LT1787HVH)
q
100
130
dB
V
EE
PSRR Negative Supply Rejection Ratio V
SENSE
= 0V, V
S
Supply = 15V, V
BIAS
= 0V,
q
100
130
dB
V
EE
= 1V to 15V (LT1787H)
V
SENSE
= 0V, V
S
Supply = 40V, V
BIAS
= 0V,
q
100
130
dB
V
EE
= 1V to 15V (LT1787HVH)
V
OS
Change in Input Offset Voltage
V
SENSE
= 0V, V
S
Supply = 36V, V
BIAS
= 0.5V to 25V (LT1787H)
q
100
130
dB
V
BIAS
with Change in V
BIAS
Voltage
V
SENSE
= 0V, V
S
Supply = 60V, V
BIAS
= 0.5V to 25V (LT1787HVH)
q
100
130
dB
I
S
+
(O)
Positive Input Sense Current
V
SENSE
= 0V
q
10
25
A
I
S
(O)
Negative Input Sense Current
V
SENSE
= 0V
q
50
115
A
I
EE(O)
Negative Supply Current
V
SENSE
= 0V
q
60
140
A
I
OUT
Output Current
V
SENSE
=
128mV
50
A
V
OUT
Output Voltage
V
SENSE
=
128mV, V
S
+
3.3V
V
BIAS
1.024
V
Ripple Rejection
V
S
+
= V
S
= 20V,
V
S
Supply = 1V, f = 1kHz
q
80
88
dB
The
q
denotes the specifications which apply over the temperature range 40
C
T
A
125
C, otherwise specifications are at
T
A
= 25
C. Total supply = (V
S
V
EE
) = 2.5V to 36V (LT1787H), 2.5V to 60V (LT1787HVH) unless otherwise specified. (Note 5)