LT1990
±250V
Input Range
G = 1, 10, Micropower,
Difference Amplifier
DESCRIPTIO
The LT
®
1990 is a micropower precision difference ampli-
fier with a very high common mode input voltage range. It
has pin selectable gains of 1 or 10. The LT1990 operates
over a
±250V
common mode voltage range on a
±15V
supply. The inputs are fault protected from common
mode voltage transients up to
±350V
and differential
voltages up to
±500V.
The LT1990 is ideally suited for both
high side and low side current or voltage monitoring.
On a single 5V supply, the LT1990 has an adjustable 85V
input range, 70dB min CMRR and draws less than 120µA
supply current. The rail-to-rail output maximizes the dy-
namic range, especially important for single supplies as
low as 2.7V.
The LT1990 is specified for single 3V, 5V and
±15V
supplies over both commercial and industrial temperature
ranges. The LT1990 is available in the 8-pin SO package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
■
■
■
■
■
■
■
■
■
■
■
■
Pin Selectable Gain of 1 or 10
High Common Mode Voltage Range:
85V Window (V
S
= 5V, 0V)
±250V
(V
S
=
±15V)
Common Mode Rejection Ratio: 70dB Min
Input Protection to
±350V
Gain Error: 0.28% Max
PSRR: 82dB Min
High Input Impedance: 2MΩ Differential,
500kΩ Common Mode
Micropower: 120µA Max Supply Current
Wide Supply Range: 2.7V to 36V
–3dB Bandwidth: 100kHz
Rail-to-Rail Output
8-Pin SO Package
FEATURES
■
■
■
■
■
■
■
Battery Cell Voltage Monitoring
High Voltage Current Sensing
Signal Acquisition in Noisy Environments
Input Protection
Fault Protected Front Ends
Level Sensing
Isolation
TYPICAL APPLICATIO
+V
SOURCE
Full-Bridge Load Current Monitor
5V
LT1990
900k
7
2
1M
100k
10k
8
– +
I
L
R
S
3
V
REF
= 1.5V
4
IN
OUT
LT6650
GND FB
54.9k
1nF
40k
40k
20k
1
1µF
1990 TA01
1M
–12V
≤
V
CM
≤
73V
V
OUT
= V
REF
±
(10 • I
L
• R
S
)
U
–
+
U
U
6
V
OUT
10k
900k
100k
5
1990f
1
LT1990
ABSOLUTE
(Notes 1, 2)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
TOP VIEW
REF 1
–IN 2
+IN 3
V
–
4
8
7
6
5
GAIN1
V
+
OUT
GAIN2
Total Supply Voltage (V
+
to V
–
) ............................... 36V
Input Voltage Range
Continuous ......................................................
±250V
Transient (0.1s) ...............................................
±350V
Differential .......................................................
±500V
Output Short-Circuit Duration (Note 3) ............ Indefinite
Operating Temperature Range (Note 4) ...–40°C to 85°C
Specified Temperature Range (Note 5) ....–40°C to 85°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec.)................. 300°C
LT1990CS8
LT1990IS8
LT1990ACS8
LT1990AIS8
S8 PART
MARKING
1990
1990A
1990I
1990AI
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 190°C/W
3V/5V ELECTRICAL CHARACTERISTICS
V
S
= 3V, 0V; V
S
= 5V, 0V; R
L
= 10k, V
CM
= V
REF
= half supply, G = 1, 10, T
A
= 25°C, unless otherwise noted. (Note 6)
SYMBOL
G
∆G
PARAMETER
Gain
Gain Error
CONDITIONS
Pins 5 and 8 = Open
Pins 5 and 8 = GND
V
OUT
= 0.5V to (+Vs) –0.75V
LT1990, G = 1
LT1990A, G = 1
G = 10, V
S
= 5V, 0V
V
S
= 5V, 0V; V
OUT
= 0.5V to 4.25V
G=1
G = 10
Guaranteed by CMRR
V
S
= 3V, 0V; V
REF
= 1.25V
V
S
= 5V, 0V; V
REF
= 1.25V
V
S
= 5V, 0V; V
REF
= 2.5V
V
S
= 3V, 0V (Note 7)
V
CM
= –5V to 25V, V
REF
= 1.25V
LT1990
LT1990A
V
S
= 5V, 0V
V
CM
= –5V to 80V, V
REF
= 1.25V
LT1990
LT1990A
V
S
= 5V, 0V (Note 7)
V
CM
= –38V to 47V, V
REF
= 2.5V
LT1990
LT1990A
V
OS
e
n
Offset Voltage, RTI
Input Noise Voltage, RTI
Noise Voltage Density, RTI
G = 1, 10
f
O
= 0.1Hz to 10Hz
f
O
= 1kHz
–5
–5
–38
MIN
TYP
1
10
0.4
0.07
0.2
0.001
0.01
0.6
0.28
0.8
0.005
%
%
%
%
%
V
V
V
MAX
UNITS
GNL
Gain Nonlinearity
V
CM
Input Voltage Range
25
80
47
CMRR
Common Mode Rejection Ratio
RTI (Referred to Input)
60
70
68
75
60
70
68
75
60
70
68
75
0.8
22
1
3
µV
P-P
µV/√Hz
1990f
2
U
dB
dB
dB
dB
dB
dB
mV
W
U
U
W W
W
LT1990
3V/5V ELECTRICAL CHARACTERISTICS
V
S
= 3V, 0V; V
S
= 5V, 0V; R
L
= 10k, V
CM
= V
REF
= half supply, G = 1, 10, T
A
= 25°C, unless otherwise noted. (Note 6)
SYMBOL
R
IN
PSRR
I
S
V
OL
V
OH
PARAMETER
Input Resistance
Power Supply Rejection Ratio, RTI
Minimum Supply Voltage
Supply Current
Output Voltage Swing LOW
Output Voltage Swing HIGH
CONDITIONS
Differential
Common Mode
V
S
= 2.7V to 12.7V, V
CM
= V
REF
= 1.25V
Guaranteed by PSRR
(Note 8)
–IN = V
+
, +IN = Half Supply (Note 8)
–IN = 0V, +IN = Half Supply
V
S
= 3V, 0V, Below V
+
V
S
= 5V, 0V, Below V
+
Short to GND (Note 9)
Short to V
+
(Note 9)
G=1
G = 10
G = 1, V
S
= 5V, 0V, V
OUT
= 0.5V to 4.5V
4V Step, G = 1, V
S
= 5V, 0V
4
13
80
MIN
TYP
2
0.5
92
2.4
105
30
100
120
8
20
100
6.5
0.5
45
1
±
0.0007
2.7
120
50
150
175
MAX
UNITS
MΩ
MΩ
dB
V
µA
mV
mV
mV
mA
mA
kHz
kHz
V/µs
µs
I
SC
BW
SR
AV
REF
Output Short-Circuit Current
Bandwidth (–3dB)
Slew Rate
Settling Time to 0.01%
Reference Gain to Output
The
●
denotes the specifications which apply over the temperature range of 0
°
C
≤
T
A
≤
70
°
C. V
S
= 3V, 0V; V
S
= 5V, 0V; R
L
= 10k,
V
CM
= V
REF
= half supply, G = 1, 10, unless otherwise noted. (Notes 4, 6)
SYMBOL
∆G
PARAMETER
Gain Error
CONDITIONS
V
OUT
= 0.5V to (+V
S
) – 0.75V
LT1990, G = 1
LT1990A, G = 1
G = 10
G = 1 (Note 10)
G = 10 (Note 10)
Guaranteed by CMRR
V
S
= 3V, 0V, V
REF
= 1.25V
V
S
= 5V, 0V, V
REF
= 1.25V
V
S
= 5V, 0V, V
REF
= 2.5V
V
S
= 3V, 0V (Note 7)
V
CM
= –5V to 25V, V
REF
= 1.25V
LT1990
LT1990A
V
S
= 5V, 0V
V
CM
= –5V to 80V, V
REF
= 1.25V
LT1990
LT1990A
V
S
= 5V, 0V (Note 7)
V
CM
= –38V to 47V, V
REF
= 2.5V
LT1990
LT1990A
V
OS
Input Offset Voltage, RTI
V
S
= 3V, 0V
G = 1, 10
V
S
= 5V, 0V
G = 1, 10
●
●
●
●
●
●
●
●
MIN
TYP
MAX
0.65
0.33
0.90
UNITS
%
%
%
ppm/°C
ppm/°C
V
V
V
G/T
V
CM
Gain vs Temperature
Input Voltage Range
2
7
–5
–5
–37
10
20
25
80
48
CMRR
Common Mode Rejection Ratio, RTI
●
●
58
68
dB
dB
●
●
58
68
dB
dB
●
●
●
●
●
●
58
68
4.1
4.1
dB
dB
mV
mV
1990f
3
LT1990
3V/5V ELECTRICAL CHARACTERISTICS
The
●
denotes the specifications which apply over the temperature range of 0
°
C
≤
T
A
≤
70
°
C. V
S
= 3V, 0V; V
S
= 5V, 0V; R
L
= 10k,
V
CM
= V
REF
= half supply, G = 1, 10, unless otherwise noted. (Notes 4, 6)
SYMBOL
V
OS
/T
V
OSH
PSRR
PARAMETER
Input Offset Voltage Drift, RTI
Input Offset Voltage Hysteresis, RTI
Power Supply Rejection Ratio, RTI
CONDITIONS
(Note 10)
(Note 11)
V
S
= 2.7V to 12.7V
V
CM
= V
REF
= 1.25V
G = 1, 10
Guaranteed by PSRR
(Note 8)
–IN = V
+
, +IN = Half Supply (Note 8)
–IN = 0V, +IN = Half Supply
V
S
= 3V, 0V, Below V
+
V
S
= 5V, 0V, Below V
+
Short to GND (Note 9)
Short to V
+
(Note 9)
●
●
MIN
TYP
5
230
MAX
22
UNITS
µV/°C
µV
●
●
●
●
●
●
●
●
78
2.7
150
60
180
205
3
11
dB
V
µA
mV
mV
mV
mA
mA
Minimum Supply Voltage
I
S
V
OL
V
OH
Supply Current
Output Voltage Swing LOW
Output Voltage Swing HIGH
I
SC
Output Short-Circuit Current
The
●
denotes the specifications which apply over the temperature range of –40°C
≤
T
A
≤
85°C. V
S
= 3V, 0V; V
S
= 5V, 0V; R
L
= 10k,
V
CM
= V
REF
= half supply, G = 1, 10, unless otherwise noted. (Notes 4, 6)
SYMBOL
∆G
PARAMETER
Gain Error
CONDITIONS
V
OUT
= 0.5V to (+V
S
) – 0.75V
LT1990, G = 1
LT1990A, G = 1
G = 10
G = 1 (Note 10)
G = 10 (Note 10)
Guaranteed by CMRR
V
S
= 3V, 0V, V
REF
= 1.25V
V
S
= 5V, 0V, V
REF
= 1.25V
V
S
= 5V, 0V, V
REF
= 2.5V
V
S
= 3V, 0V (Note 7)
V
CM
= –5V to 25V, V
REF
= 1.25V
LT1990
LT1990A
V
S
= 5V, 0V
V
CM
= –5V to 80V, V
REF
= 1.25V
LT1990
LT1990A
V
S
= 5V, 0V (Note 7)
V
CM
= –38V to 47V, V
REF
= 2.5V
LT1990
LT1990A
V
OS
Input Offset Voltage, RTI
V
S
= 3V, 0V
G = 1, 10
V
S
= 5V, 0V
G = 1, 10
V
OS
/T
V
OSH
PSRR
Input Offset Voltage Drift, RTI
Input Offset Voltage Hysteresis, RTI
Power Supply Rejection Ratio, RTI
(Note 10)
(Note 11)
V
S
= 2.7V to 12.7V
V
CM
= V
REF
= 1.25V
●
●
●
●
●
●
●
●
MIN
TYP
MAX
0.67
0.35
0.95
UNITS
%
%
%
ppm/°C
ppm/°C
V
V
V
G/T
V
CM
Gain vs Temperature
Input Voltage Range
2
7
–5
–5
–37
10
20
25
80
48
CMRR
Common Mode Rejection Ratio, RTI
●
●
57
67
dB
dB
●
●
57
67
dB
dB
●
●
●
●
●
●
●
●
●
57
67
4.5
4.5
5
230
76
22
dB
dB
mV
mV
µV/°C
µV
dB
1990f
4
LT1990
3V/5V ELECTRICAL CHARACTERISTICS
The
●
denotes the specifications which apply over the temperature range of –40°C
≤
T
A
≤
85°C. V
S
= 3V, 0V; V
S
= 5V, 0V;
R
L
= 10k, V
CM
= V
REF
= half supply, G = 1, 10, unless otherwise noted. (Notes 4, 6)
SYMBOL
I
S
V
OL
V
OH
PARAMETER
Minimum Supply Voltage
Supply Current
Output Voltage Swing LOW
Output Voltage Swing HIGH
CONDITIONS
Guaranteed by PSRR
(Note 8)
–IN = V
+
, +IN = Half Supply (Note 8)
–IN = 0V, +IN = Half Supply
V
S
= 3V, 0V, Below V
+
V
S
= 5V, 0V, Below V
+
Short to GND (Note 9)
Short to V
+
(Note 9)
●
●
●
●
●
●
●
MIN
TYP
MAX
2.7
170
70
200
225
UNITS
V
µA
mV
mV
mV
mA
mA
I
SC
Output Short-Circuit Current
2
8
±15V
ELECTRICAL CHARACTERISTICS
V
S
=
±15V,
R
L
= 10k, V
CM
= V
REF
= 0V, G = 1, 10, T
A
= 25°C, unless otherwise noted. (Note 6)
SYMBOL
G
∆G
PARAMETER
Gain
Gain Error
CONDITIONS
Pins 5 and 8 = Open
Pins 5 and 8 = V
REF
V
OUT
=
±10V
LT1990, G = 1
LT1990A, G = 1
G = 10
V
OUT
=
±10V
G=1
G = 10
Guaranteed by CMRR
V
CM
= –250V to 250V
LT1990
LT1990A
G = 1, 10
f
O
= 0.1Hz to 10Hz
f
O
= 1kHz
Differential
Common Mode
V
S
=
±1.35V
to
±18V
Guaranteed by PSRR
±14.5
Short to V
–
Short to V
+
G=1
G = 10
G = 1, V
OUT
=
±10V
10V Step, G = 1
0.3
6
15
82
–250
60
70
68
75
0.9
22
1
2
0.5
100
±1.2
140
±14.79
9
22
105
7
0.55
60
1
±
0.0007
±1.35
180
5.2
MIN
TYP
1
10
0.4
0.07
0.2
0.6
0.28
0.8
%
%
%
%
%
V
dB
dB
mV
µV
P-P
µV/√Hz
MΩ
MΩ
dB
V
µA
V
mA
mA
kHz
kHz
V/µs
µs
MAX
UNITS
GNL
Gain Nonlinearity
0.0008 0.002
0.005 0.02
250
V
CM
CMRR
Input Voltage Range
Common Mode Rejection Ratio, RTI
V
OS
e
n
R
IN
PSRR
I
S
V
OUT
I
SC
BW
SR
AV
REF
Offset Voltage, RTI
Input Noise Voltage, RTI
Noise Voltage Density, RTI
Input Resistance
Power Supply Rejection Ratio, RTI
Minimum Supply Voltage
Supply Current
Output Voltage Swing
Output Short-Circuit Current
Bandwidth
Slew Rate
Settling Time to 0.01%
Reference Gain to Output
1990f
5
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