LT1990
±250V Input Range
G = 1, 10, Micropower,
Difference Amplifier
DESCRIPTIO
U
FEATURES
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Pin Selectable Gain of 1 or 10
High Common Mode Voltage Range:
85V Window (VS = 5V, 0V)
±250V (VS = ±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
The LT®1990 is a micropower precision difference amplifier 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 dynamic 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.
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APPLICATIO S
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Battery Cell Voltage Monitoring
High Voltage Current Sensing
Signal Acquisition in Noisy Environments
Input Protection
Fault Protected Front Ends
Level Sensing
Isolation
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
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TYPICAL APPLICATIO
Full-Bridge Load Current Monitor
+VSOURCE
5V
LT1990
900k
10k
8
7
– +
2
1M
3
1M
100k
–
RS
6
VOUT
+
VREF = 1.5V
IL
4
OUT
IN
LT6650
GND FB
–12V ≤ VCM ≤ 73V
VOUT = VREF ± (10 • IL • RS)
10k
1nF
54.9k
40k
5
900k
40k
100k
20k
1
1990 TA01
1µF
1990fb
1
LT1990
U
W W
W
ABSOLUTE
AXI U RATI GS
U
W
U
PACKAGE/ORDER I FOR ATIO
(Notes 1, 2)
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)
LT1990C .............................................. –40°C to 85°C
LT1990I ............................................... –40°C to 85°C
LT1990H ........................................... –40°C to 125°C
Specified Temperature Range (Note 5)
LT1990C .............................................. –40°C to 85°C
LT1990I ............................................... –40°C to 85°C
LT1990H ........................................... –40°C to 125°C
Junction Temperature ........................................... 150°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec.)................. 300°C
TOP VIEW
REF 1
8
GAIN1
–IN 2
7
V+
+IN 3
6
OUT
V– 4
5
GAIN2
S8 PACKAGE
8-LEAD PLASTIC SO
TJMAX = 150°C, θJA = 190°C/W
ORDER PART NUMBER
LT1990CS8
LT1990IS8
LT1990HS8
LT1990ACS8
LT1990AIS8
LT1990AHS8
S8 PART MARKING
1990
1990I
1990H
1990A
1990AI
1990AH
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
3V/5V ELECTRICAL CHARACTERISTICS
VS = 3V, 0V; VS = 5V, 0V; RL = 10k, VCM = VREF = half supply, G = 1, 10, TA = 25°C, unless otherwise noted. (Note 6)
SYMBOL
PARAMETER
CONDITIONS
G
Gain
Pins 5 and 8 = Open
Pins 5 and 8 = VREF
∆G
Gain Error
VOUT = 0.5V to (+Vs) –0.75V
LT1990, G = 1
LT1990A, G = 1
G = 10, VS = 5V, 0V
VS = 5V, 0V; VOUT = 0.5V to 4.25V
G=1
G = 10
GNL
VCM
CMRR
Gain Nonlinearity
Input Voltage Range
Common Mode Rejection Ratio
RTI (Referred to Input)
MIN
TYP
MAX
UNITS
0.4
0.07
0.2
0.6
0.28
0.8
%
%
%
0.001
0.01
0.005
%
%
25
80
47
V
V
V
1
10
Guaranteed by CMRR
VS = 3V, 0V; VREF = 1.25V
VS = 5V, 0V; VREF = 1.25V
VS = 5V, 0V; VREF = 2.5V
–5
–5
–38
VS = 3V, 0V (Note 7)
VCM = –5V to 25V, VREF = 1.25V
LT1990
LT1990A
60
70
68
75
dB
dB
VS = 5V, 0V
VCM = –5V to 80V, VREF = 1.25V
LT1990
LT1990A
60
70
68
75
dB
dB
VS = 5V, 0V (Note 7)
VCM = –38V to 47V, VREF = 2.5V
LT1990
LT1990A
60
70
68
75
dB
dB
1990fb
2
LT1990
3V/5V ELECTRICAL CHARACTERISTICS
VS = 3V, 0V; VS = 5V, 0V; RL = 10k, VCM = VREF = half supply, G = 1, 10, TA = 25°C, unless otherwise noted. (Note 6)
SYMBOL
PARAMETER
CONDITIONS
VOS
Offset Voltage, RTI
en
MIN
TYP
MAX
G = 1, 10
0.8
3
Input Noise Voltage, RTI
fO = 0.1Hz to 10Hz
22
µVP-P
Noise Voltage Density, RTI
fO = 1kHz
1
µV/√Hz
RIN
Input Resistance
Differential
Common Mode
PSRR
Power Supply Rejection Ratio, RTI
VS = 2.7V to 12.7V, VCM = VREF = 1.25V
Minimum Supply Voltage
Guaranteed by PSRR
2.4
2.7
80
UNITS
mV
2
0.5
MΩ
MΩ
92
dB
V
IS
Supply Current
(Note 8)
105
120
µA
VOL
Output Voltage Swing LOW
–IN = V+, +IN = Half Supply (Note 8)
30
50
mV
VOH
Output Voltage Swing HIGH
–IN = 0V, +IN = Half Supply
VS = 3V, 0V, Below V+
VS = 5V, 0V, Below V+
100
120
150
175
mV
mV
ISC
Output Short-Circuit Current
Short to GND (Note 9)
Short to V+ (Note 9)
BW
Bandwidth (–3dB)
SR
AVREF
4
13
8
20
mA
mA
G=1
G = 10
100
6.5
kHz
kHz
Slew Rate
G = 1, VS = 5V, 0V, VOUT = 0.5V to 4.5V
0.5
V/µs
Settling Time to 0.01%
4V Step, G = 1, VS = 5V, 0V
45
µs
Reference Gain to Output
G=1
G = 10
1 ± 0.0007
1 ± 0.007
The ● denotes the specifications which apply over the temperature range of 0°C ≤ TA ≤ 70°C. VS = 3V, 0V; VS = 5V, 0V; RL = 10k,
VCM = VREF = half supply, G = 1, 10, unless otherwise noted. (Notes 4, 6)
SYMBOL
PARAMETER
CONDITIONS
∆G
Gain Error
VOUT = 0.5V to (+VS) – 0.75V
LT1990, G = 1
LT1990A, G = 1
G = 10
●
●
●
LT1990C/LT1990I
MIN
TYP
MAX
UNITS
0.65
0.33
0.90
%
%
%
G/T
Gain vs Temperature
G = 1 (Note 10)
G = 10 (Note 10)
●
●
VCM
Input Voltage Range
Guaranteed by CMRR
VS = 3V, 0V, VREF = 1.25V
VS = 5V, 0V, VREF = 1.25V
VS = 5V, 0V, VREF = 2.5V
●
●
●
–5
–5
–37
VS = 3V, 0V (Note 7)
VCM = –5V to 25V, VREF = 1.25V
LT1990
LT1990A
●
●
58
68
dB
dB
VS = 5V, 0V
VCM = –5V to 80V, VREF = 1.25V
LT1990
LT1990A
●
●
58
68
dB
dB
VS = 5V, 0V (Note 7)
VCM = –38V to 47V, VREF = 2.5V
LT1990
LT1990A
●
●
58
68
dB
dB
CMRR
Common Mode Rejection Ratio, RTI
2
7
10
20
ppm/°C
ppm/°C
25
80
48
V
V
V
1990fb
3
LT1990
3V/5V ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the temperature range of 0°C ≤ TA ≤ 70°C. VS = 3V, 0V; VS = 5V, 0V; RL = 10k,
VCM = VREF = half supply, G = 1, 10, unless otherwise noted. (Notes 4, 6)
LT1990C/LT1990I
MIN
TYP
MAX
SYMBOL
PARAMETER
CONDITIONS
VOS
Input Offset Voltage, RTI
VS = 3V, 0V
G = 1, 10
●
4.1
mV
VS = 5V, 0V
G = 1, 10
●
4.1
mV
22
µV/°C
VOS/T
Input Offset Voltage Drift, RTI
(Note 10)
●
5
VOSH
Input Offset Voltage Hysteresis, RTI
(Note 11)
●
230
PSRR
Power Supply Rejection Ratio, RTI
VS = 2.7V to 12.7V
VCM = VREF = 1.25V
G = 1, 10
●
Guaranteed by PSRR
●
2.7
Minimum Supply Voltage
UNITS
µV
78
dB
V
IS
Supply Current
(Note 8)
●
150
µA
VOL
Output Voltage Swing LOW
–IN = V+, +IN = Half Supply (Note 8)
●
60
mV
VOH
Output Voltage Swing HIGH
–IN = 0V, +IN = Half Supply
VS = 3V, 0V, Below V+
VS = 5V, 0V, Below V+
●
●
180
205
mV
mV
Short to GND (Note 9)
Short to V+ (Note 9)
●
●
ISC
Output Short-Circuit Current
3
11
mA
mA
The ● denotes the specifications which apply over the temperature range of –40°C ≤ TA ≤ 85°C. VS = 3V, 0V; VS = 5V, 0V; RL = 10k,
VCM = VREF = half supply, G = 1, 10, unless otherwise noted. (Notes 4, 6)
SYMBOL
PARAMETER
CONDITIONS
∆G
Gain Error
VOUT = 0.5V to (+VS) – 0.75V
LT1990, G = 1
LT1990A, G = 1
G = 10
●
●
●
LT1990C/LT1990I
MIN
TYP
MAX
UNITS
0.67
0.35
0.95
%
%
%
G/T
Gain vs Temperature
G = 1 (Note 10)
G = 10 (Note 10)
●
●
VCM
Input Voltage Range
Guaranteed by CMRR
VS = 3V, 0V, VREF = 1.25V
VS = 5V, 0V, VREF = 1.25V
VS = 5V, 0V, VREF = 2.5V
●
●
●
–5
–5
–37
VS = 3V, 0V (Note 7)
VCM = –5V to 25V, VREF = 1.25V
LT1990
LT1990A
●
●
57
67
dB
dB
VS = 5V, 0V
VCM = –5V to 80V, VREF = 1.25V
LT1990
LT1990A
●
●
57
67
dB
dB
VS = 5V, 0V (Note 7)
VCM = –38V to 47V, VREF = 2.5V
LT1990
LT1990A
●
●
57
67
dB
dB
CMRR
Common Mode Rejection Ratio, RTI
2
7
10
20
ppm/°C
ppm/°C
25
80
48
V
V
V
1990fb
4
LT1990
3V/5V ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the temperature range of –40°C ≤ TA ≤ 85°C. VS = 3V, 0V; VS = 5V, 0V;
RL = 10k, VCM = VREF = half supply, G = 1, 10, unless otherwise noted. (Notes 4, 6)
LT1990C/LT1990I
MIN
TYP
MAX
SYMBOL
PARAMETER
CONDITIONS
UNITS
VOS
Input Offset Voltage, RTI
VS = 3V, 0V
G = 1, 10
●
4.5
mV
VS = 5V, 0V
G = 1, 10
●
4.5
mV
22
µV/°C
VOS/T
Input Offset Voltage Drift, RTI
(Note 10)
●
5
VOSH
Input Offset Voltage Hysteresis, RTI
(Note 11)
●
230
PSRR
Power Supply Rejection Ratio, RTI
VS = 2.7V to 12.7V
VCM = VREF = 1.25V
●
Minimum Supply Voltage
Guaranteed by PSRR
●
2.7
V
Supply Current
(Note 8)
●
170
µA
VOL
Output Voltage Swing LOW
–IN = V+, +IN = Half Supply (Note 8)
●
70
mV
VOH
Output Voltage Swing HIGH
–IN = 0V, +IN = Half Supply
VS = 3V, 0V, Below V+
VS = 5V, 0V, Below V+
●
●
200
275
mV
mV
Short to GND (Note 9)
Short to V+ (Note 9)
●
●
IS
ISC
Output Short-Circuit Current
µV
76
dB
2
8
mA
mA
3V/5V ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the temperature range of –40°C ≤ TA ≤ 125°C. VS = 3V, 0V; VS = 5V, 0V; RL = 10k,
VCM = VREF = half supply, G = 1, 10, unless otherwise noted. (Notes 4, 6)
SYMBOL
PARAMETER
CONDITIONS
MIN
∆G
Gain Error
VOUT = 0.5V to (+VS) – 0.75V
LT1990, G = 1
LT1990A, G = 1
G = 10
●
●
●
LT1990H
TYP
MAX
UNITS
0.69
0.37
0.97
%
%
%
G/T
Gain vs Temperature
G = 1 (Note 10)
G = 10 (Note 10)
●
●
VCM
Input Voltage Range
Guaranteed by CMRR
VS = 3V, 0V, VREF = 1.25V
VS = 5V, 0V, VREF = 1.25V
VS = 5V, 0V, VREF = 2.5V
●
●
●
–5
–5
–37
VS = 3V, 0V (Note 7)
VCM = –5V to 25V, VREF = 1.25V
LT1990
LT1990A
●
●
56
66
dB
dB
VS = 5V, 0V
VCM = –5V to 80V, VREF = 1.25V
LT1990
LT1990A
●
●
56
66
dB
dB
VS = 5V, 0V (Note 7)
VCM = –38V to 47V, VREF = 2.5V
LT1990
LT1990A
●
●
56
66
dB
dB
CMRR
Common Mode Rejection Ratio, RTI
2
7
10
20
ppm/°C
ppm/°C
25
80
48
V
V
V
1990fb
5
LT1990
3V/5V ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the temperature range of –40°C ≤ TA ≤ 125°C. VS = 3V, 0V; VS = 5V, 0V; RL = 10k,
VCM = VREF = half supply, G = 1, 10, unless otherwise noted. (Notes 4, 6)
SYMBOL
PARAMETER
CONDITIONS
MIN
VOS
Input Offset Voltage, RTI
VS = 3V, 0V
G = 1, 10
●
VS = 5V, 0V
G = 1, 10
●
LT1990H
TYP
MAX
5.2
mV
5.2
mV
22
µV/°C
VOS/T
Input Offset Voltage Drift, RTI
(Note 10)
●
5
VOSH
Input Offset Voltage Hysteresis, RTI
(Note 11)
●
250
PSRR
Power Supply Rejection Ratio, RTI
VS = 2.7V to 12.7V
VCM = VREF = 1.25V
●
Guaranteed by PSRR
●
2.7
Minimum Supply Voltage
UNITS
µV
75
dB
V
IS
Supply Current
(Note 8)
●
200
µA
VOL
Output Voltage Swing LOW
–IN = V+, +IN = Half Supply (Note 8)
●
80
mV
VOH
Output Voltage Swing HIGH
–IN = 0V, +IN = Half Supply
VS = 3V, 0V, Below V+
VS = 5V, 0V, Below V+
●
●
230
275
mV
mV
Short to GND (Note 9)
Short to V+ (Note 9)
●
●
ISC
Output Short-Circuit Current
1
5
mA
mA
±15V ELECTRICAL CHARACTERISTICS
VS = ±15V, RL = 10k, VCM = VREF = 0V, G = 1, 10, TA = 25°C, unless otherwise noted. (Note 6)
SYMBOL
PARAMETER
CONDITIONS
G
Gain
Pins 5 and 8 = Open
Pins 5 and 8 = VREF
∆G
Gain Error
VOUT = ±10V
LT1990, G = 1
LT1990A, G = 1
G = 10
GNL
Gain Nonlinearity
MIN
TYP
MAX
UNITS
0.6
0.28
0.8
%
%
%
0.0008 0.002
0.005 0.02
%
%
1
10
0.4
0.07
0.2
VOUT = ±10V
G=1
G = 10
VCM
Input Voltage Range
Guaranteed by CMRR
–250
CMRR
Common Mode Rejection Ratio, RTI
VCM = –250V to 250V
LT1990
LT1990A
60
70
250
68
75
V
dB
dB
VOS
Offset Voltage, RTI
G = 1, 10
0.9
en
Input Noise Voltage, RTI
fO = 0.1Hz to 10Hz
22
µVP-P
Noise Voltage Density, RTI
fO = 1kHz
1
µV/√Hz
RIN
Input Resistance
Differential
Common Mode
PSRR
Power Supply Rejection Ratio, RTI
VS = ±1.35V to ±18V
Minimum Supply Voltage
Guaranteed by PSRR
IS
Supply Current
VOUT
Output Voltage Swing
82
±14.5
5.2
mV
2
0.5
MΩ
MΩ
100
dB
±1.2
±1.35
V
140
180
µA
±14.79
V
1990fb
6
LT1990
±15V ELECTRICAL CHARACTERISTICS
VS = ±15V, RL = 10k, VCM = VREF = 0V, G = 1, 10, TA = 25°C, unless otherwise noted. (Note 6)
SYMBOL
PARAMETER
CONDITIONS
ISC
Output Short-Circuit Current
Short to V–
BW
Bandwidth
SR
Slew Rate
G = 1, VOUT = ±10V
Settling Time to 0.01%
10V Step, G = 1
Reference Gain to Output
G=1
G = 10
AVREF
Short to V+
MIN
TYP
6
15
9
22
mA
mA
105
7
kHz
kHz
0.55
V/µs
G=1
G = 10
0.3
MAX
UNITS
µs
60
1 ± 0.0007
1 ± 0.007
The ● denotes the specifications which apply over the temperature range of 0°C ≤ TA ≤ 70°C. VS = ±15V, RL = 10k, VCM = VREF = 0V,
G = 1, 10, unless otherwise noted. (Notes 4, 6)
LT1990C/LT1990I
MIN
TYP
MAX
UNITS
●
●
●
0.65
0.33
0.9
%
%
%
VOUT = ±10V
G=1
G = 10
●
●
0.0025
0.025
%
%
Gain vs Temperature
G = 1 (Note 10)
G = 10 (Note 10)
●
●
VCM
Input Voltage Range
Guaranteed by CMRR
●
–250
CMRR
Common Mode Rejection Ratio, RTI
VCM = –250V to 250V
LT1990
LT1990A
●
●
59
68
SYMBOL
PARAMETER
CONDITIONS
∆G
Gain Error
VOUT = ±10V
LT1990, G = 1
LT1990A, G = 1
G = 10
GNL
G/T
Gain Nonlinearity
VOS
Input Offset Voltage, RTI
G = 1, 10
●
VOS/T
Input Offset Voltage Drift, RTI
(Note 10)
●
VOSH
Input Offset Voltage Hysteresis, RTI
(Note 11)
●
PSRR
Power Supply Rejection Ratio, RTI
VS = ±1.35V to ±18V
●
Minimum Supply Voltage
Guaranteed by PSRR
●
2
7
10
20
ppm/°C
ppm/°C
250
V
dB
dB
5
6.2
mV
22
µV/°C
µV
250
80
dB
±1.35
V
230
µA
IS
Supply Current
●
VOUT
Output Voltage Swing
●
±14.4
Short to V+
●
●
5
13
mA
mA
G = 1, VOUT = ±10V
●
0.25
V/µs
ISC
Output Short-Circuit Current
SR
Slew Rate
Short to V–
V
1990fb
7
LT1990
±15V ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the temperature range of –40°C ≤ TA ≤ 85°C. VS = ±15V, RL = 10k, VCM = VREF = 0V,
G = 1, 10, unless otherwise noted. (Notes 4, 6)
LT1990C/LT1990I
MIN
TYP
MAX
UNITS
●
●
●
0.67
0.35
0.95
%
%
%
VOUT = ±10V
G=1
G = 10
●
●
0.003
0.03
%
%
Gain vs Temperature
G = 1 (Note 10)
G = 10 (Note 10)
●
●
VCM
Input Voltage Range
Guaranteed by CMRR
●
–250
CMRR
Common Mode Rejection Ratio, RTI
VCM = –250V to 250V
LT1990
LT1990A
●
●
58
67
SYMBOL
PARAMETER
CONDITIONS
∆G
Gain Error
VOUT = ±10V
LT1990, G = 1
LT1990A, G = 1
G = 10
GNL
G/T
Gain Nonlinearity
VOS
Input Offset Voltage, RTI
G = 1, 10
●
VOS/T
Input Offset Voltage Drift, RTI
(Note 10)
●
VOSH
Input Offset Voltage Hysteresis, RTI
(Note 11)
●
PSRR
Power Supply Rejection Ratio, RTI
VS = ±1.35V to ±18V
●
Minimum Supply Voltage
Guaranteed by PSRR
●
2
7
10
20
ppm/°C
ppm/°C
250
V
dB
dB
5
6.7
mV
22
µV/°C
µV
250
78
dB
±1.35
V
280
µA
IS
Supply Current
●
VOUT
Output Voltage Swing
●
±14.3
V
Short to V+
●
●
3
10
mA
mA
G = 1, VOUT = ±10V
●
0.2
V/µs
ISC
Output Short-Circuit Current
SR
Slew Rate
Short to V–
±15V ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the temperature range of –40°C ≤ TA ≤ 125°C. VS = ±15V, RL = 10k, VCM = VREF = 0V,
G = 1, 10, unless otherwise noted. (Notes 4, 6)
LT1990H
TYP
MAX
UNITS
●
●
●
0.69
0.37
0.97
%
%
%
VOUT = ±10V
G=1
G = 10
●
●
0.0035
0.035
%
%
Gain vs Temperature
G = 1 (Note 10)
G = 10 (Note 10)
●
●
VCM
Input Voltage Range
Guaranteed by CMRR
●
–250
CMRR
Common Mode Rejection Ratio, RTI
VCM = –250V to 250V
LT1990
LT1990A
●
●
57
66
SYMBOL
PARAMETER
CONDITIONS
∆G
Gain Error
VOUT = ±10V
LT1990, G = 1
LT1990A, G = 1
G = 10
GNL
G/T
Gain Nonlinearity
MIN
VOS
Input Offset Voltage, RTI
G = 1, 10
●
VOS/T
Input Offset Voltage Drift, RTI
(Note 10)
●
2
7
10
20
ppm/°C
ppm/°C
250
V
dB
dB
5
7.4
mV
22
µV/°C
1990fb
8
LT1990
±15V ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the temperature range of –40°C ≤ TA ≤ 125°C. VS = ±15V, RL = 10k, VCM = VREF = 0V,
G = 1, 10, unless otherwise noted. (Notes 4, 6)
PARAMETER
CONDITIONS
VOSH
Input Offset Voltage Hysteresis, RTI
(Note 11)
●
PSRR
Power Supply Rejection Ratio, RTI
VS = ±1.35V to ±18V
●
Minimum Supply Voltage
Guaranteed by PSRR
●
±1.35
V
●
330
µA
IS
Supply Current
VOUT
Output Voltage Swing
ISC
Output Short-Circuit Current
SR
Slew Rate
MIN
LT1990H
TYP
MAX
SYMBOL
UNITS
µV
250
77
dB
●
±14.2
V
Short to V+
●
●
1.5
7
mA
mA
G = 1, VOUT = ±10V
●
Short to V –
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 device. Extensive use of
ESD protection devices are used internal to the LT1990, 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.
Note 4: The LT1990C/LT1990I are guaranteed functional over the
operating temperature range of – 40°C to 85°C. The LT1990H is
guaranteed functional over the operating temperature range of –40°C
to 125°C.
Note 5: The LT1990C is guaranteed to meet the specified performance
from 0°C to70°C and is designed, characterized and expected to meet
specified performance from –40°C to 85°C but is not tested or QA
0.1
V/µs
sampled at these temperatures. The LT1990I is guaranteed to meet
specified performance from –40°C to 85°C. The LT1990H is guaranteed to
meet specified performance from –40°C to 125°C.
Note 6: G = 10 limits are guaranteed by correlation to G = 1 tests and gain
error tests at G = 10.
Note 7: Limits are guaranteed by correlation to –5V to 80V CMRR tests.
Note 8: VS = 3V limits are guaranteed by correlation to VS = 5V and
VS = ±15V tests.
Note 9: VS = 5V limits are guaranteed by correlation to VS = 3V and
VS = ±15V tests.
Note 10: This parameter is not 100% tested.
Note 11: Hysteresis in offset voltage is created by package stress that
differs depending on whether the IC was previously at a higher or lower
temperature. Offset voltage hysteresis is always measured at 25°C, but the
IC is cycled to 85°C I-grade (70°C C-grade or 125°C H-grade) or –40°C
I/H-grade (0°C C-grade) before successive measurement.
1990fb
9
LT1990
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current
vs Supply Voltage
200
TA = 125°C
180
TA = 85°C
160
TA = 25°C
140
TA = –40°C
120
TA = –55°C
100
80
V + – 0.01
VS = 5V, 0V
60
130
120
110
100
90
80
5
10 15 20 25 30
SUPPLY VOLTAGE (V)
60
–50
40
35
–25
0
25
50
75
TEMPERATURE (°C)
100
1990 G01
TA = 125°C
–1
TA = 25°C
TA = 25°C
+1
SINKING
(+IN = –2.5V)
+0.1
TA = 125°C
TA = –55°C
TA = –55°C
V + –0.01
VS = ±2.5V
G = 10
–0.1 NO LOAD
OUTPUT VOLTAGE WITH
RESPECT TO SUPPLY (V)
TA = 125°C
TA = 25°C
–1
+1
TA = 25°C
+0.1
TA = –55°C
TA = 25°C
+1
TA = 25°C
0
0.2
0.4
0.6
0.8
DIFFERENTIAL INPUT VOLTAGE (±V)
MAXIMUM INPUT VOLTAGE (V)
TA = –55°C
10
TA = 25°C
TA = 125°C
SINK
–10
TA = 125°C
–15
TA = –55°C
–20
TA = 25°C
–25
1.0
2
4
8
10 12
6
SUPPLY VOLTAGE (±V)
14
16
1990 G07
OUTPUT FULLY
SATURATED
G = 10 G = 1
2
4
6
8
10 12
SUPPLY VOLTAGE (±V)
300
VREF = 4V
150
VREF = 1.25V
100
VREF = 2.5V
50
VREF = 1.25V
0
VREF = 2.5V
–50
16
1990 G06
V – = 0V
TA = –40°C TO 85°C
200
14
Input Voltage Range vs Split
Supply Voltage
VREF = 0V
TA = –40°C TO 85°C
200
100
0
–100
–200
VREF = 4V
–100
0
V – +0.01
0
Input Voltage Range vs Single
Supply Voltage
SOURCE
0
+0.1 G = 10, V+IN = V –/10
G=1
G = 10
OUTPUT FULLY
SATURATED
1990 G05
250
–5
V–IN = 0V
VREF = 0V
NO LOAD
TA = 25°C
G = 1, V+IN = V –
TA = –55°C
V – +0.01
25
5
–0.1 G = 10, V = V+/10
+IN
TA = 125°C
Output Short-Circuit Current
vs Supply Voltage
15
G = 1, V+IN = V+
TA = 125°C
1990 G04
20
V + –0.01
TA = –55°C
+0.1
4.0
100
Output Voltage Swing vs
Supply Voltage
–1
TA = 125°C
0.5 1.0 1.5 2.0 2.5 3.0 3.5
DIFFERENTIAL INPUT VOLTAGE (±V)
0.01
0.1
1
10
OUTPUT CURRENT (mA)
1990 G03
OUTPUT SWING WITH
RESPECT TO SUPPLY (V)
VS = ±2.5V
G=1
–0.1 NO LOAD
0
V – +0.01
0.001
Output Voltage vs
Input Voltage, G = 10
V + –0.01
OUTPUT VOLTAGE WITH
RESPECT TO SUPPLY (V)
SOURCING
(+IN = 2.5V)
1990 G02
Output Voltage vs
Input Voltage, G = 1
V – +0.01
125
MAXIMUM INPUT VOLTAGE (V)
0
OUTPUT SHORT-CIRCUIT CURRENT (mA)
– 0.1
70
40
–30
VS = ±2.5V
–IN = 0V
G=1
TA = –55°C
140
SUPPLY CURRENT (µA)
SUPPLY CURRENT (µA)
150
VREF = VOUT = 1.25V
V – = 0V
OUTPUT VOLTAGE SWING
WITH RESPECT TO SUPPLY (V)
220
Output Voltage Swing
vs Load Current
Supply Current
vs Temperature
3
7
9
11
13
5
POSITIVE SUPPLY VOLTAGE (V)
15
1990 G08
–300
1
3
9
7
11
5
SUPPLY VOLTAGE (±V)
13
15
1990 G09
1990fb
10
LT1990
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Common Mode Rejection Ratio
vs Frequency
Gain vs Frequency
50
VS = 5V, 0V
40 TA = 25°C
VS = 5V, 0V
TA = 25°C
G = 1 OR 10
REFERRED TO INPUT
90
80
30
70
20
60
10
GAIN (dB)
COMMON MODE REJECTION RATIO (dB)
100
50
40
0
G = 10
G=1
–10
–20
30
20
–30
10
–40
0
100
10k
1k
FREQUENCY (Hz)
–50
100
100k 200k
1k
10k
100k
FREQUENCY (Hz)
1M
1990 G10
–3dB Bandwidth vs Supply
Voltage, G = 1
120
8
1.0
TA = 25°C
TA = 25°C
RL = 10k
TA = –55°C
TA = –55°C
FREQUENCY (kHz)
TA = 125°C
100
0.8
7
105
TA = 25°C
95
90
85
80
TA = 25°C
6
SLEW RATE (V/µs)
110
FREQUENCY (kHz)
Slew Rate vs Supply Voltage,
G=1
–3dB Bandwidth vs Supply
Voltage, G = 10
TA = 25°C
115
1990 G12
TA = 125°C
5
4
–SR
0.6
+SR
0.4
0.2
75
70
3
0
2
6
8
4
10 12
SUPPLY VOLTAGE (±V)
14
0
0
16
2
6
8
4
10 12
SUPPLY VOLTAGE (±V)
1990 G13
0
1.0
TA = 25°C
RL = 10k
0.6
VS = ±15V
RL = 10k
0.5
+SR
0.2
0.1
–SR
SLEW RATE (V/µs)
SLEW RATE (V/µs)
–SR
0.6
+SR
0.4
0.2
0
0
2
8
6
10 12
4
SUPPLY VOLTAGE (±V)
14
16
1990 G16
8
6
10 12
4
SUPPLY VOLTAGE (±V)
0
–50 –25
14
16
Slew Rate vs Temperature
G = 10
0.8
0.3
2
1990 G15
Slew Rate vs Temperature
G=1
0.4
SLEW RATE (V/µs)
16
1990 G14
Slew Rate vs Supply Voltage,
G = 10
0.5
14
VS = ±15V
RL = 10k
0.4
0.3
–SR
+SR
0.2
0.1
50
25
75
0
TEMPERATURE (°C)
100
125
1990 G17
0
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
1990 G18
1990fb
11
LT1990
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Power Supply Rejection Ratio
vs Frequency
70
G = 10
G=1
100
10
VS = 5V, 0V
TA = 25°C
1
100
10k
1k
FREQUENCY (Hz)
60
VS = 5V, 0V
TA = 25°C
G=1
50
40
30
G = 10
20
10
0
–10
–20
SETTLING TIME (µs)
SETTLING TIME (µs)
0.01% OF
STEP
0.01% OF
STEP
0.1% OF
STEP
0.01% OF
STEP
260
0.01% OF
STEP
240
220
200
0.1% OF
STEP
180
0.1% OF
STEP
160
8
140
–10 –8 –6 –4 –2 0 2 4
OUTPUT STEP (V)
10
VS = ±1.5V TO ±15V
TA = 25°C
1000
100
6
8
1
10
10
100
1000
FREQUENCY (Hz)
10000
1990 G24
Overshoot vs Capacitive Load
30
VS = ±1.5V TO ±15V
TA = 25°C
G=1
VOUT = ±50mV
GAIN = 1
RL = 10k
25
OVERSHOOT (%)
NOISE VOLTAGE (10µV/DIV)
50
1990 G21
0.01 to 1Hz Noise Voltage
REF
10
20
30
40
TIME AFTER POWER-UP (S)
1990 G23
0.1 to 10Hz Noise Voltage
VS = ±1.5V TO ±15V
TA = 25°C
G=1
0
10000
280
1990 G22
NOISE VOLTAGE (10µV/DIV)
–40
Voltage Noise Density
vs Frequency
VS = ±15V
RL = 10k
300
50
6
–20
100k 200k
1k
10k
FREQUENCY (Hz)
320
VS = ±15V
RL = 10k
20
–10 –8 –6 –4 –2 0 2 4
OUTPUT STEP (V)
0
Settling Time vs Output Step,
G = 10
60
0.1% OF
STEP
20
1990 G20
Settling Time vs Output Step,
G=1
30
40
–60
100
1990 G19
40
VS = ±15V
TA = 25°C
REFERRED TO INPUT
–30
–40
10
100k 200k
Warm-Up Drift vs Time
60
VOLTAGE NOISE DENSITY (nV/√Hz)
OUTPUT IMPEDANCE (Ω)
1k
POWER SUPPLY REJECTION RATIO (dB)
5k
CHANGE IN OFFSET VOLTAGE (µV)
Output Impedance vs Frequency
REF
20
15
VS = 3V, 0V
10
VS = ±15V
5
0
1
2
3
4 5 6
TIME (S)
7
8
9
10
1990 G25
0
10 20 30 40 50 60 70 80 90 100
TIME (S)
1990 G26
10
100
1000
CAPACITIVE LOAD (pF)
10000
1990 G27
1990fb
12
LT1990
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Small Signal Transient Response
1.5V
VS = 3V, 0V
G = 1, –1
RL = 10k
VREF = 1.5V
GND
1990 G28
50µs/DIV
Large Signal Transient Response
5V/DIV
50mV/DIV
50mV/DIV
Small Signal Transient Response
VS = ±15V
G = 1, –1
RL = 10k
VREF = GND
1990 G29
50µs/DIV
GND
VS = ±15V
G = 1, –1
RL = 10k
VREF = GND
50µs/DIV
1990 G30
W
BLOCK DIAGRA
R5
900k
R7
10k
8 GAIN1
V+ 7
R1
1M
R6
100k
–
–IN 2
R2
1M
6 OUT
+
+IN 3
V– 4
R10
10k
R8
900k
R3
40k
5 GAIN2
R4
40k
1
R9
100k
1990 SS
REF
U
U
U
PI FU CTIO S
REF (Pin 1): Reference Input. Sets the output level when
the difference between the inputs is zero.
–IN (Pin 2): Inverting Input. Connects a 1MΩ resistor to
the op amp’s inverting input. Designed to permit high
voltage operation.
+IN (Pin 3): Noninverting Input. Connects a 1MΩ resistor
to the op amp’s noninverting input. Designed to permit
high voltage operation.
V– (Pin 4): Negative Power Supply. Can be either ground
(in single supply applications) or a negative voltage (in
split supply applications).
GAIN2 (Pin 5): Gain = 10 Select Input. Configures the
amplifier for a gain of 10 when connected to the GAIN1 pin
and the REF pin. The gain is equal to one when both GAIN2
and GAIN1 are open. See Applications section for additional functions.
OUT (Pin 6): Output. VOUT = G • (V+IN – V–IN) + VREF, in the
basic configuration.
V+ (Pin 7): Positive Power Supply. Can range from 2.7V to
36V above the V– voltage.
GAIN1 (Pin 8): Gain = 10 Select Input. Configures the
amplifier for a gain of 10 when connected to the GAIN2 pin
and the REF pin. The gain is equal to one when both GAIN1
and GAIN2 are open. See Applications section for additional functions.
1990fb
13
LT1990
U
W
U
U
APPLICATIO S I FOR ATIO
Primary Features
VCM+ ≤ 27 • V+ – 26 • VREF – 23 – VGAIN
The LT1990 is a complete gain-block solution for high
input common mode voltage applications, incorporating a
low power precision operational amplifier providing railto-rail output swing along with on-chip precision thin-film
resistors for high accuracy. The Block Diagram shows the
internal architecture of the part. The on-chip resistors
form a modified difference amplifier including a reference
port for introducing offset or other additive waveforms.
With pin-strapping alone either unity gain or gain of 10 is
produced with high precision. The resistor network is
designed to produce internal common-mode voltage division of 27 so that a very large input range is available
compared to the power supply voltage(s) used by the
LT1990 itself. The LT1990 is ideally suited to situations
where relatively small signals need to be extracted from
high voltage circuits, as is the case in many current
monitoring instrumentation applications for example. With
the ability to accept a range of input voltages well outside
the limits of the local power rails and its greater than 1MΩ
input impedances, development of precision low power
over-the-top and under-the-bottom instrumentation designs is greatly simplified with the LT1990 single chip
solution over conventional discrete implementations.
VCM– ≥ 27 • V– – 26 • VREF + 27 – VGAIN
Classic Difference Amplifier
Used in the basic difference amplifier topology where the
gain G is pin-strap configurable to be unity or ten, the
following relationship is realized:
VO = G • (V+IN – V–IN) + VREF
To operate in unity gain, the GAIN1 and GAIN2 pins are left
disconnected. For G = 10 operation, the GAIN1 and GAIN2
pins are simply connected to the REF pin.
The input common mode range capability is up to ±250V,
governed by the following relationships:
For G = 1 and G = 10 where GAIN1 and GAIN2 are only tied
together (not grounded,etc):
VCM+ ≤ 27 • V+ – 26 • VREF – 23
VCM– ≥ 27 • V – – 26 • VREF + 27
For G = 10 where GAIN1 and GAIN2 are tied to a common
potential VGAIN:
For split supplies over about ±11V, the full ±250V common
mode range is normally available (with VREF a small
fraction of the supply). With lower supply voltages, an
appropriate selection of VREF can tailor the input common
mode range to a specific requirement. As an example, the
following low supply voltage scenarios are readily implemented with the LT1990:
Supply
VREF
VCM Range
+3V
1.25V
–5V to 25V (e.g. 12V automotive environment)
+5V
1.25V
–5V to 80V (e.g. 42V automotive environment)
+5V
4.00V
–77V to 8V (e.g. telecom environment;
use downward signaling)
Configuring Other Gains
An intermediate gain G ranging between 1 and 10 may be
produced by placing an adjustable resistance between the
GAIN1 and GAIN2 pins according to the following nominal
relationship:
RGAIN ≈ (180k/(G – 1)) – 20k
While the expression is exact, the value is approximate
because the absolute resistance of the internal network
could vary on a unit-to-unit basis by as much as ±30%
from the nominal figures and the external gain resistance
is required to accommodate that deviation. Once adjusted, however, the gain stability is excellent by virtue of
the –30ppm/°C typical temperature coefficient offered by
the on-chip thin-film resistor process.
Preserving and Enhancing Common Mode Rejection
The basic difference amplifier topology of the LT1990
requires that source impedances seen by the input pins
+IN and –IN, should be matched to within a few tens of
ohms to avoid increasing common mode induced errors
beyond the basic production limits of the part. Known
source imbalances beyond that level should be compensated for by the addition of series resistance to the lowerimpedance source. Also the source impedance of a signal
connected to the REF pin must be on the order of a few
ohms or less to preserve the high accuracy of the LT1990.
1990fb
14
LT1990
U
W
U U
APPLICATIO S I FOR ATIO
following relationship:
While the LT1990 comes from the factory with an excellent
CMRR, some precision applications with a large applied
common mode voltage may require a method to trim out
residual common mode error. This is easily accomplished
by adding series resistance to each input, +IN and –IN,
such that an adjustable resistance difference of ±1kΩ is
provided. This is most easily realized by adding a fixed
1kΩ in series with one of the inputs, and a 2kΩ trimmer in
series with the other as shown in Figure 1. The trim range
of this configuration is ±0.1% for the internal gain resistor
matching, so a much more finely resolved correction is
available using the LT1990 than is realizable with ordinary
discrete solutions. In applications where the input
common mode voltage is relatively constant and large
(perhaps at or beyond the supply range), this same
configuration can be treated as an offset adjustment.
1k
VO = 10 • (V+IN – V–IN + VGAIN2 – VGAIN1) + VREF
Unlike the main inputs, the GAIN1 and GAIN2 pins are
clamped by substrate diodes and ESD structures, thus the
operating voltage range of these pins is limited to V– – 0.2V
to V– + 36V. If the GAIN inputs are brought beyond the
operating input range, care must be taken to limit the input
currents to less than 10mA to prevent damage to the device.
For best results in this mode of operation the common mode
voltage of the GAIN1 and GAIN2 pins should be equal to the
REF pin voltage. Also, since the gain setting resistors associated with the GAIN1 and GAIN2 inputs are in the 10kΩ area,
low source impedances are particularly important to preserve
the precision of the LT1990.
This dual differential input mode of operation is used in the
circuit as shown in Figure 2.
–
This circuit is a high efficiency H-bridge driver that is PWM
modulated to provide a controlled current to an electromagnet coil. Since the common mode voltage of the
current sense resistor RS varies with operating current
and the coil properties, a differential feedback is required.
In this application, it was desirable to allow the control
input to utilize the wide common mode range port (+IN and
–IN) so that constraints on input referencing are eliminated. The GAIN1 and GAIN2 pins always operate within
the supply range and both ports operate with a gain of 10
to develop the loop error. The LTC1923 provides the loop
integrator and PWM functions of the servo.
LT1990
2k
+
Figure 1. Optional CMRR Trim
Dual Differential-Input Arithmetic Block
The internal resistor network topology of the LT1990
allows the GAIN1 and GAIN2 pins to be used as another
differential input in addition to the normal +IN and –IN
port. This can be a very useful function for implementing
servo-loop differential error amplifiers, for example. In
this mode of operation, the output is governed by the
10k
PLLLPF
RT
RSLEW
CT
330pF
82k
VIN+
100k
3
+
5
VDD
G2
LT1990
20k
2
100k
10nF
VDD
7
–
REF
8
6
G1
SDSYNC
VREF
1µF
100k
100k
10nF
4
CNTRL
PDRVB
EAOUT
NDRVB
10µF
MPA*
L1
10µH
1
FB
VIN–
VDD
LTC1923
ICOIL = (VIN+ – VIN)/(10 • RS)
(i.e. ±1A FOR ±1V)
C1, C2, C3: TAIYO YUDEN JMK325BJ226MM-T (X7R)
L1, L2: SUMIDA CDRH6D2B-220NC
*MNA, MPA: SILICONIX Si9801
**MNB, MPB: SILICONIX Si9801
VDD
VREF
1µF
10k
10k
AGND
1µF
PGND
SS
NDRVA
ILIM
PDRVA
VSET
CS +
FAULT
VTHRM
CS –
C3
22µF
C1
MNB** 22µF
MPB**
L2
10µH
C2
22µF
MNA*
0.1
RS
0.1
ITEC
H/C
TEC +
VTEC
TEC –
ICOIL ELECTROMAGNET
COIL
1990 F02
Figure 2. PWM-Based ±1A Electromagnet Current Controller
1990fb
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
LT1990
U
TYPICAL APPLICATIO
Telecom Supply Current Monitor
+
LOAD
IL
Selectable Gain Amplifier
Boosted Bidirectional Controlled Current Source
+V
5V
48V
+V
–
3
7
+
RS
G2
LT1990
2
–
4
G1
VIN
5 6
+
8
7
+
VIN–
2
–
4 G1
1
REF
1k
G2
LT1990
VOUT
1
–77V ≤ VCM ≤ 8V
VOUT = VREF – (10 • IL • RS)
3
REF
VREF = 4V
CZT751
5 6
VOUT
8
VCTL
3
+
6
LT1990
2
–V
–
+
10µF
4
RSENSE
1
2N7002
4
5
IN
OUT
LT6650
1
GND FB
2
7
REF
ILOAD
1nF
174k
1k
GAIN_SEL
(HI = 10X, LO = 1X)
20k
CZT651
2N7002
–V
1990 AI01
1µF
ILOAD = VCTL/RSENSE ≤ 100mA
EXAMPLE: FOR RSENSE =10Ω,
OUTPUT IS 1mA PER 10mV INPUT
1990 AI02
1990 AI04
Bidirectional Controlled Current Source
+V
VCTL
3
+
2
–
7
LT1990
4
1
REF
–V
6
RSENSE
ILOAD
ILOAD = VCTL/RSENSE ≤ 5mA
EXAMPLE: FOR RSENSE =100Ω,
OUTPUT IS 1mA PER 100mV INPUT
1990 AI03
U
PACKAGE DESCRIPTIO
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
RECOMMENDED SOLDER PAD LAYOUT
.010 – .020
× 45°
(0.254 – 0.508)
.045 ±.005
.050 BSC
.008 – .010
(0.203 – 0.254)
.245
MIN
.160 ±.005
8
.053 – .069
(1.346 – 1.752)
NOTE:
1. DIMENSIONS IN
.050
(1.270)
BSC
.014 – .019
(0.355 – 0.483)
TYP
.150 – .157
(3.810 – 3.988)
NOTE 3
.228 – .244
(5.791 – 6.197)
INCHES
(MILLIMETERS)
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
.030 ±.005
TYP
5
.004 – .010
(0.101 – 0.254)
0°– 8° TYP
.016 – .050
(0.406 – 1.270)
.189 – .197
(4.801 – 5.004)
NOTE 3
7
6
1
2
3
4
SO8 0303
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1787
Precision High Side Current Sense Amplifier
On-Chip Precision Resistor Array
LT1789
Micropower Instrumentation Amplifier
Micropower, Precision, G = 1 to 1000
LTC1921
Dual –48V Supply and Fuse Monitor
Withstands ±200V Transients
LT1991
High Accuracy Difference Amplifier
Micropower, Precision, Pin Selectable G = –13 to 14
LT1995
30MHz, 1000V/µs Gain Selectable Amplifier
Pin Selectable G = –7 to 8
LT6910
Single Supply Programmable Gain Amplifier
Digitally Controlled, SOT-23, G = 0 to 100
1990fb
16
LT 0406 REV B • PRINTED IN USA
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