LINER LT1790BIS6-2.048-PBF Micropower sot-23 low dropout reference family Datasheet

LT1790
Micropower SOT-23
Low Dropout Reference Family
FEATURES
DESCRIPTION
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The LT®1790 is a family of SOT-23 micropower low dropout
series references that combine high accuracy and low drift
with low power dissipation and small package size. These
micropower references use curvature compensation to
obtain a low temperature coefficient and trimmed precision thin-film resistors to achieve high output accuracy. In
addition, each LT1790 is post-package trimmed to greatly
reduce the temperature coefficient and increase the output
accuracy. Output accuracy is further assured by excellent
line and load regulation. Special care has been taken to
minimize thermally induced hysteresis.
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High Accuracy:
A Grade—0.05% Max
B Grade—0.1% Max
Low Drift:
A Grade—10ppm/°C Max
B Grade—25ppm/°C Max
Low Thermal Hysteresis 40ppm (Typical) –40°C to 85°C
Low Supply Current: 60μA Max
Sinks and Sources Current
Low Dropout Voltage
Guaranteed Operational –40°C to 125°C
Wide Supply Range to 18V
Available Output Voltage Options: 1.25V, 2.048V,
2.5V, 3V, 3.3V, 4.096V and 5V
Low Profile (1mm) ThinSOT™ Package
APPLICATIONS
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Handheld Instruments
Negative Voltage References
Industrial Control Systems
Data Acquisition Systems
Battery-Operated Equipment
The LT1790s are ideally suited for battery-operated systems because of their small size, low supply current and
reduced dropout voltage. These references provide supply current and power dissipation advantages over shunt
references that must idle the entire load current to operate.
Since the LT1790 can also sink current, it can operate as
a micropower negative voltage reference with the same
performance as a positive reference.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Positive Connection for LT1790-2.5
Typical VOUT Distribution for LT1790-2.5
50
0.1μF
LT1790-2.5
1, 2
6
40
1μF
1790 TA01
167 UNITS
45
VOUT = 2.5V
NUMBER OF UNITS
2.6V ≤ VIN ≤ 18V
4
LT1790B LIMITS
35
LT1790A LIMITS
30
25
20
15
10
5
0
2.498
2.499 2.500
2.501
OUTPUT VOLTAGE (V)
2.502
1790 TA02
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LT1790
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
(Note 1)
Input Voltage.............................................................20V
Specified Temperature Range
Commercial............................................. 0°C to 70°C
Industrial .............................................– 40°C to 85°C
Output Short-Circuit Duration .......................... Indefinite
Operating Temperature Range
(Note 2)..................................................–40°C to 125°C
Storage Temperature Range
(Note 3).................................................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
TOP VIEW
GND 1
6 VOUT
GND 2
5 DNC*
DNC* 3
4 VIN
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
TJMAX = 150°C, θJA = 230°C/W
*DNC: DO NOT CONNECT
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
SPECIFIED TEMPERATURE RANGE
LT1790ACS6-1.25#PBF
LT1790ACS6-1.25#TRPBF
LTXT
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790AIS6-1.25#PBF
LT1790AIS6-1.25#TRPBF
LTXT
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790BCS6-1.25#PBF
LT1790BCS6-1.25#TRPBF
LTXT
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790BIS6-1.25#PBF
LT1790BIS6-1.25#TRPBF
LTXT
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790ACS6-2.048#PBF
LT1790ACS6-2.048#TRPBF
LTXU
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790AIS6-2.048#PBF
LT1790AIS6-2.048#TRPBF
LTXU
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790BCS6-2.048#PBF
LT1790BCS6-2.048#TRPBF
LTXU
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790BIS6-2.048#PBF
LT1790BIS6-2.048#TRPBF
LTXU
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790ACS6-2.5#PBF
LT1790ACS6-2.5#TRPBF
LTPZ
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790AIS6-2.5#PBF
LT1790AIS6-2.5#TRPBF
LTPZ
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790BCS6-2.5#PBF
LT1790BCS6-2.5#TRPBF
LTPZ
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790BIS6-2.5#PBF
LT1790BIS6-2.5#TRPBF
LTPZ
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790ACS6-3#PBF
LT1790ACS6-3#TRPBF
LTQA
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790AIS6-3#PBF
LT1790AIS6-3#TRPBF
LTQA
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790BCS6-3#PBF
LT1790BCS6-3#TRPBF
LTQA
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790BIS6-3#PBF
LT1790BIS6-3#TRPBF
LTQA
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790ACS6-3.3#PBF
LT1790ACS6-3.3#TRPBF
LTXW
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790AIS6-3.3#PBF
LT1790AIS6-3.3#TRPBF
LTXW
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790BCS6-3.3#PBF
LT1790BCS6-3.3#TRPBF
LTXW
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790BIS6-3.3#PBF
LT1790BIS6-3.3#TRPBF
LTXW
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790ACS6-4.096#PBF
LT1790ACS6-4.096#TRPBF
LTQB
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790AIS6-4.096#PBF
LT1790AIS6-4.096#TRPBF
LTQB
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790BCS6-4.096#PBF
LT1790BCS6-4.096#TRPBF
LTQB
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790BIS6-4.096#PBF
LT1790BIS6-4.096#TRPBF
LTQB
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790ACS6-5#PBF
LT1790ACS6-5#TRPBF
LTQC
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790AIS6-5#PBF
LT1790AIS6-5#TRPBF
LTQC
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790BCS6-5#PBF
LT1790BCS6-5#TRPBF
LTQC
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790BIS6-5#PBF
LT1790BIS6-5#TRPBF
LTQC
6-Lead Plastic TSOT-23
–40°C to 85°C
1790fb
2
LT1790
ORDER INFORMATION
LEAD BASED FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
SPECIFIED TEMPERATURE RANGE
LT1790ACS6-1.25
LT1790ACS6-1.25#TR
LTXT
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790AIS6-1.25
LT1790AIS6-1.25#TR
LTXT
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790BCS6-1.25
LT1790BCS6-1.25#TR
LTXT
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790BIS6-1.25
LT1790BIS6-1.25#TR
LTXT
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790ACS6-2.048
LT1790ACS6-2.048#TR
LTXU
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790AIS6-2.048
LT1790AIS6-2.048#TR
LTXU
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790BCS6-2.048
LT1790BCS6-2.048#TR
LTXU
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790BIS6-2.048
LT1790BIS6-2.048#TR
LTXU
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790ACS6-2.5
LT1790ACS6-2.5#TR
LTPZ
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790AIS6-2.5
LT1790AIS6-2.5#TR
LTPZ
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790BCS6-2.5
LT1790BCS6-2.5#TR
LTPZ
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790BIS6-2.5
LT1790BIS6-2.5#TR
LTPZ
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790ACS6-3
LT1790ACS6-3#TR
LTQA
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790AIS6-3
LT1790AIS6-3#TR
LTQA
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790BCS6-3
LT1790BCS6-3#TR
LTQA
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790BIS6-3
LT1790BIS6-3#TR
LTQA
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790ACS6-3.3
LT1790ACS6-3.3#TR
LTXW
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790AIS6-3.3
LT1790AIS6-3.3#TR
LTXW
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790BCS6-3.3
LT1790BCS6-3.3#TR
LTXW
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790BIS6-3.3
LT1790BIS6-3.3#TR
LTXW
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790ACS6-4.096
LT1790ACS6-4.096#TR
LTQB
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790AIS6-4.096
LT1790AIS6-4.096#TR
LTQB
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790BCS6-4.096
LT1790BCS6-4.096#TR
LTQB
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790BIS6-4.096
LT1790BIS6-4.096#TR
LTQB
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790ACS6-5
LT1790ACS6-5#TR
LTQC
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790AIS6-5
LT1790AIS6-5#TR
LTQC
6-Lead Plastic TSOT-23
–40°C to 85°C
LT1790BCS6-5
LT1790BCS6-5#TR
LTQC
6-Lead Plastic TSOT-23
0°C to 70°C
LT1790BIS6-5
LT1790BIS6-5#TR
LTQC
6-Lead Plastic TSOT-23
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
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/
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3
LT1790
AVAILABLE OPTIONS
TEMPERATURE RANGE
OUTPUT
VOLTAGE
INITIAL
ACCURACY
TEMPERATURE
COEFFICIENT
0°C TO 70°C
–40°C TO 85°C
ORDER PART NUMBER
ORDER PART NUMBER
1.250V
0.05%
0.1%
10ppm/°C
25ppm/°C
LT1790ACS6-1.25
LT1790BCS6-1.25
LT1790AIS6-1.25
LT1790BIS6-1.25
2.048V
0.05%
0.1%
10ppm/°C
25ppm/°C
LT1790ACS6-2.048
LT1790BCS6-2.048
LT1790AIS6-2.048
LT1790BIS6-2.048
2.500V
0.05%
0.1%
10ppm/°C
25ppm/°C
LT1790ACS6-2.5
LT1790BCS6-2.5
LT1790AIS6-2.5
LT1790BIS6-2.5
3.000V
0.05%
0.1%
10ppm/°C
25ppm/°C
LT1790ACS6-3
LT1790BCS6-3
LT1790AIS6-3
LT1790BIS6-3
3.300V
0.05%
0.1%
10ppm/°C
25ppm/°C
LT1790ACS6-3.3
LT1790BCS6-3.3
LT1790AIS6-3.3
LT1790BIS6-3.3
4.096V
0.05%
0.1%
10ppm/°C
25ppm/°C
LT1790ACS6-4.096
LT1790BCS6-4.096
LT1790AIS6-4.096
LT1790BIS6-4.096
5.000V
0.05%
0.1%
10ppm/°C
25ppm/°C
LT1790ACS6-5
LT1790BCS6-5
LT1790AIS6-5
LT1790BIS6-5
1.25V ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the specified
temperature range, otherwise specifications are at TA = 25°C. CL = 1μF and VIN = 2.6V, unless otherwise noted.
PARAMETER
CONDITIONS
Output Voltage (Notes 3, 4)
Output Voltage Temperature Coefficient (Note 5)
MIN
TYP
MAX
LT1790A
1.24937
–0.05
1.25
1.25062
0.05
V
%
LT1790B
1.24875
–0.1
1.25
1.25125
0.1
V
%
LT1790AC
l
l
1.24850
–0.12
1.25
1.2515
0.12
V
%
LT1790AI
l
l
1.24781
–0.175
1.25
1.25219
0.175
V
%
LT1790BC
l
l
1.24656
–0.275
1.25
1.25344
0.275
V
%
LT1790BI
l
l
1.24484
–0.4125
1.25
1.25516
0.4125
V
%
5
12
10
25
ppm/°C
ppm/°C
50
170
220
ppm/V
ppm/V
100
160
250
ppm/mA
ppm/mA
120
180
250
ppm/mA
ppm/mA
1.95
2.15
2.50
2.90
2.95
V
V
V
V
TMIN ≤ TA ≤ TMAX
LT1790A
LT1790B
Line Regulation
2.6V ≤ VIN ≤ 18V
Load Regulation (Note 6)
IOUT Source = 5mA, VIN = 2.8V
IOUT Sink = 1mA, VIN = 3.2V
Minimum Operating Voltage (Note 7)
UNITS
VIN, ΔVOUT = 0.1%
IOUT = 0mA
IOUT Source = 5mA
IOUT Sink = 1mA
l
l
l
l
l
l
l
l
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LT1790
1.25V ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the specified
temperature range, otherwise specifications are at TA = 25°C. CL = 1μF and VIN = 2.6V, unless otherwise noted.
PARAMETER
CONDITIONS
Supply Current
No Load
Minimum Operating Current—
Negative Output (See Figure 7)
MIN
TYP
MAX
35
60
75
μA
μA
VOUT = – 1.25V, ±0.1%
100
125
μA
Turn-On Time
CLOAD = 1μF
250
μs
Output Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
10
14
μVP-P
μVRMS
50
ppm/√kHr
25
40
ppm
ppm
l
Long-Term Drift of Output Voltage (Note 9)
Hysteresis (Note 10)
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
l
l
UNITS
2.048V ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the
specified temperature range, otherwise specifications are at TA = 25°C. CL = 1μF and VIN = 2.8V, unless otherwise noted.
PARAMETER
CONDITIONS
Output Voltage (Notes 3, 4)
Output Voltage Temperature Coefficient (Note 5)
MIN
TYP
MAX
LT1790A
2.04697
–0.05
2.048
2.04902
0.05
V
%
LT1790B
2.04595
–0.1
2.048
2.05005
0.1
V
%
LT1790AC
l
l
2.04554
–0.12
2.048
2.05046
0.12
V
%
LT1790AI
l
l
2.04442
–0.175
2.048
2.05158
0.175
V
%
LT1790BC
l
l
2.04237
–0.275
2.048
2.05363
0.275
V
%
LT1790BI
l
l
2.03955
–0.4125
2.048
2.05645
0.4125
V
%
5
12
10
25
ppm/°C
ppm/°C
50
170
220
ppm/V
ppm/V
120
200
280
ppm/mA
ppm/mA
130
260
450
ppm/mA
ppm/mA
50
100
500
750
450
mV
mV
mV
mV
35
60
75
μA
μA
125
μA
TMIN ≤ TA ≤ TMAX
LT1790A
LT1790B
Line Regulation
2.8V ≤ VIN ≤ 18V
Load Regulation (Note 6)
IOUT Source = 5mA
IOUT Sink = 3mA
Dropout Voltage (Note 7)
UNITS
VIN – VOUT, ΔVOUT = 0.1%
IOUT = 0mA
IOUT Source = 5mA
IOUT Sink = 3mA
l
l
l
l
l
l
l
l
Supply Current
No Load
Minimum Operating Current—
Negative Output (See Figure 7)
VOUT = – 2.048V, 0.1%
100
Turn-On Time
CLOAD = 1μF
350
l
μs
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LT1790
2.048V ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the
specified temperature range, otherwise specifications are at TA = 25°C. CL = 1μF and VIN = 2.8V, unless otherwise noted.
PARAMETER
CONDITIONS
Output Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
MIN
Long-Term Drift of Output Voltage (Note 9)
Hysteresis (Note 10)
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
l
l
TYP
MAX
UNITS
22
41
μVP-P
μVRMS
50
ppm/√kHr
25
40
ppm
ppm
2.5V ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the specified
temperature range, otherwise specifications are at TA = 25°C. CL = 1μF and VIN = 3V, unless otherwise noted.
PARAMETER
CONDITIONS
Output Voltage (Notes 3, 4)
Output Voltage Temperature Coefficient (Note 5)
MIN
TYP
MAX
LT1790A
2.49875
–0.05
2.5
2.50125
0.05
V
%
LT1790B
2.4975
–0.1
2.5
2.5025
0.1
V
%
LT1790AC
l
l
2.4970
–0.12
2.5
2.5030
0.12
V
%
LT1790AI
l
l
2.49563
–0.175
2.5
2.50438
0.175
V
%
LT1790BC
l
l
2.49313
–0.275
2.5
2.50688
0.275
V
%
LT1790BI
l
l
2.48969
–0.4125
2.5
2.51031
0.4125
V
%
5
12
10
25
ppm/°C
ppm/°C
50
170
220
ppm/V
ppm/V
80
160
250
ppm/mA
ppm/mA
70
110
300
ppm/mA
ppm/mA
50
100
120
450
250
mV
mV
mV
mV
35
60
80
μA
μA
125
μA
TMIN ≤ TA ≤ TMAX
LT1790A
LT1790B
Line Regulation
3V ≤ VIN ≤ 18V
Load Regulation (Note 6)
IOUT Source = 5mA
IOUT Sink = 3mA
Dropout Voltage (Note 7)
UNITS
VIN – VOUT, ΔVOUT = 0.1%
IOUT = 0mA
IOUT Source = 5mA
IOUT Sink = 3mA
l
l
l
l
l
l
l
l
Supply Current
No Load
Minimum Operating Current—
Negative Output (See Figure 7)
VOUT = – 2.5V, 0.1%
100
Turn-On Time
CLOAD = 1μF
700
μs
Output Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
32
48
μVP-P
μVRMS
50
ppm/√kHr
25
40
ppm
ppm
l
Long-Term Drift of Output Voltage (Note 9)
Hysteresis (Note 10)
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
l
l
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LT1790
3V ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the specified
temperature range, otherwise specifications are at TA = 25°C. CL = 1μF and VIN = 3.5V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
Output Voltage (Notes 3, 4)
LT1790A
2.9985
–0.05
3
3.0015
0.05
V
%
LT1790B
2.9970
–0.10
3
3.0030
0.10
V
%
Output Voltage Temperature Coefficient (Note 5)
LT1790AC
l
l
2.99640
–0.12
3
3.00360
0.12
V
%
LT1790AI
l
l
2.99475
–0.175
3
3.00525
0.175
V
%
LT1790BC
l
l
2.99175
–0.275
3
3.00825
0.275
V
%
LT1790BI
l
l
2.98763
–0.4125
3
3.01238
0.4125
V
%
5
12
10
25
ppm/°C
ppm/°C
50
170
220
ppm/V
ppm/V
80
160
250
ppm/mA
ppm/mA
70
110
300
ppm/mA
ppm/mA
50
100
120
450
250
mV
mV
mV
mV
35
60
80
μA
μA
125
μA
TMIN ≤ TA ≤ TMAX
LT1790A
LT1790B
Line Regulation
3.5V ≤ VIN ≤ 18V
Load Regulation (Note 6)
IOUT Source = 5mA
IOUT Sink = 3mA
Dropout Voltage (Note 7)
UNITS
VIN – VOUT, ΔVOUT = 0.1%
IOUT = 0mA
IOUT Source = 5mA
IOUT Sink = 3mA
l
l
l
l
l
l
l
l
Supply Current
No Load
Minimum Operating Current—
Negative Output (See Figure 7)
VOUT = – 3V, 0.1%
100
Turn-On Time
CLOAD = 1μF
700
μs
Output Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
50
56
μVP-P
μVRMS
50
ppm/√kHr
25
40
ppm
ppm
l
Long-Term Drift of Output Voltage (Note 9)
Hysteresis (Note 10)
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
l
l
1790fb
7
LT1790
3.3V ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the specified
temperature range, otherwise specifications are at TA = 25°C. CL = 1μF and VIN = 3.8V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
Output Voltage (Notes 3, 4)
LT1790A
3.29835
–0.05
3.3
3.30165
0.05
V
%
LT1790B
3.2967
–0.10
3.3
3.3033
0.10
V
%
Output Voltage Temperature Coefficient (Note 5)
LT1790AC
l
l
3.29604
–0.120
3.3
3.30396
0.120
V
%
LT1790AI
l
l
3.29423
–0.175
3.3
3.30578
0.175
V
%
LT1790BC
l
l
3.29093
–0.275
3.3
3.30908
0.275
V
%
LT1790BI
l
l
3.28639
–0.4125
3.3
3.31361
0.4125
V
%
5
12
10
25
ppm/°C
ppm/°C
50
170
220
ppm/V
ppm/V
80
160
250
ppm/mA
ppm/mA
70
110
300
ppm/mA
ppm/mA
50
100
120
450
250
mV
mV
mV
mV
35
60
80
μA
μA
125
μA
TMIN ≤ TA ≤ TMAX
LT1790A
LT1790B
Line Regulation
3.8V ≤ VIN ≤ 18V
Load Regulation (Note 6)
IOUT Source = 5mA
IOUT Sink = 3mA
Dropout Voltage (Note 7)
UNITS
VIN – VOUT, ΔVOUT = 0.1%
IOUT = 0mA
IOUT Source = 5mA
IOUT Sink = 3mA
l
l
l
l
l
l
l
l
Supply Current
No Load
Minimum Operating Current—
Negative Output (See Figure 7)
VOUT = – 3.3V, 0.1%
100
Turn-On Time
CLOAD = 1μF
700
μs
Output Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
50
67
μVP-P
μVRMS
50
ppm/√kHr
25
40
ppm
ppm
l
Long-Term Drift of Output Voltage (Note 9)
Hysteresis (Note 10)
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
l
l
1790fb
8
LT1790
4.096V ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the
specified temperature range, otherwise specifications are at TA = 25°C. CL = 1μF and VIN = 4.6V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Output Voltage (Notes 3, 4)
LT1790A
4.094
–0.05
4.096
4.098
0.05
V
%
LT1790B
4.092
–0.10
4.096
4.10
0.10
V
%
Output Voltage Temperature Coefficient (Note 5)
LT1790AC
l
l
4.09108
–0.120
4.096
4.10092
0.120
V
%
LT1790AI
l
l
4.08883
–0.175
4.096
4.10317
0.175
V
%
LT1790BC
l
l
4.08474
–0.275
4.096
4.10726
0.275
V
%
LT1790BI
l
l
4.07910
–0.4125
4.096
4.11290
0.4125
V
%
5
12
10
25
ppm/°C
ppm/°C
50
170
220
ppm/V
ppm/V
80
160
250
ppm/mA
ppm/mA
70
110
300
ppm/mA
ppm/mA
50
100
120
450
250
mV
mV
mV
mV
35
60
80
μA
μA
125
μA
TMIN ≤ TA ≤ TMAX
LT1790A
LT1790B
Line Regulation
4.6V ≤ VIN ≤ 18V
Load Regulation (Note 6)
IOUT Source = 5mA
IOUT Sink = 3mA
Dropout Voltage (Note 7)
VIN – VOUT, ΔVOUT = 0.1%
IOUT = 0mA
IOUT Source = 5mA
IOUT Sink = 3mA
l
l
l
l
l
l
l
l
Supply Current
No Load
Minimum Operating Current—
Negative Output (See Figure 7)
VOUT = – 4.096V, 0.1%
100
Turn-On Time
CLOAD = 1μF
700
μs
Output Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
60
89
μVP-P
μVRMS
50
ppm/√kHr
25
40
ppm
ppm
l
Long-Term Drift of Output Voltage (Note 9)
Hysteresis (Note 10)
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
l
l
1790fb
9
LT1790
5V ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the specified
temperature range, otherwise specifications are at TA = 25°C. CL = 1μF and VIN = 5.5V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
Output Voltage (Notes 3, 4)
LT1790A
4.9975
–0.05
5
5.0025
0.05
V
%
LT1790B
4.995
–0.10
5
5.005
0.10
V
%
Output Voltage Temperature Coefficient (Note 5)
LT1790AC
l
l
4.99400
–0.120
5
5.00600
0.120
V
%
LT1790AI
l
l
4.99125
–0.175
5
5.00875
0.175
V
%
LT1790BC
l
l
4.98625
–0.275
5
5.01375
0.275
V
%
LT1790BI
l
l
4.97938
–0.4125
5
5.02063
0.4125
V
%
5
12
10
25
ppm/°C
ppm/°C
50
170
220
ppm/V
ppm/V
80
160
250
ppm/mA
ppm/mA
70
110
300
ppm/mA
ppm/mA
50
100
120
450
250
mV
mV
mV
mV
35
60
80
μA
μA
125
μA
TMIN ≤ TA ≤ TMAX
LT1790A
LT1790B
Line Regulation
5.5V ≤ VIN ≤ 18V
Load Regulation (Note 6)
IOUT Source = 5mA
IOUT Sink = 3mA
Dropout Voltage (Note 7)
UNITS
VIN – VOUT, ΔVOUT = 0.1%
IOUT = 0mA
IOUT Source = 5mA
IOUT Sink = 3mA
l
l
l
l
l
l
l
l
Supply Current
No Load
Minimum Operating Current—
Negative Output (See Figure 7)
VOUT = – 5V, 0.1%
100
Turn-On Time
CLOAD = 1μF
700
μs
Output Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
80
118
μVP-P
μVRMS
50
ppm/√kHr
25
40
ppm
ppm
l
Long-Term Drift of Output Voltage (Note 9)
Hysteresis (Note 10)
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
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: The LT1790 is guaranteed functional over the operating
temperature range of – 40°C to 125°C. The LT1790-1.25 at 125°C is
typically less than 2% above the nominal voltage. The other voltage
options are typically less than 0.25% above their nominal voltage.
Note 3: If the part is stored outside of the specified temperature range, the
output voltage may shift due to hysteresis.
l
l
Note 4: ESD (Electrostatic Discharge) sensitive device. Extensive use of
ESD protection devices are used internal to the LT1790, however, high
electrostatic discharge can damage or degrade the device. Use proper ESD
handling precautions.
Note 5: Temperature coefficient is measured by dividing the change in
output voltage by the specified temperature range. Incremental slope is
also measured at 25°C.
Note 6: Load regulation is measured on a pulse basis from no load to the
specified load current. Output changes due to die temperature change
must be taken into account separately.
Note 7: Excludes load regulation errors.
1790fb
10
LT1790
ELECTRICAL CHARACTERISTICS
Note 8: Peak-to-peak noise is measured with a single pole highpass filter
at 0.1Hz and a 2-pole lowpass filter at 10Hz. The unit is enclosed in a still
air environment to eliminate thermocouple effects on the leads. The test
time is 10 seconds. Integrated RMS noise is measured from 10Hz to 1kHz
with the HP3561A analyzer.
Note 9: Long-term drift typically has a logarithmic characteristic and
therefore changes after 1000 hours tend to be smaller than before that
time. Long-term drift is affected by differential stress between the IC and
the board material created during board assembly. See the Applications
Information section.
Note 10: Hysteresis in the output voltage is created by package stress that
differs depending on whether the IC was previously at a higher or lower
temperature. Output voltage is always measured at 25°C, but the IC is
cycled to 85°C or –40°C before a successive measurements. Hysteresis
is roughly proportional to the square of the temperature change.
Hysteresis is not a problem for operational temperature excursions where
the instrument might be stored at high or low temperature. See the
Applications Information section.
1.25V TYPICAL PERFORMANCE CHARACTERISTICS
Each of the voltage options have similar performance curves. For the 3V, 3.3V and the 4.096V options,
the curves can be estimated based on the 2.5V and 5V curves.
Minimum Input-Output Voltage
Differential (Sourcing)
Output Voltage Temperature Drift
1.253
Minimum Input-Output Voltage
Differential (Sinking)
1.0
10
FOUR TYPICAL PARTS
0.9
1.251
1.250
1.249
TA = 125°C
VOLTAGE DIFFERENTIAL (V)
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
1.252
TA = –55°C
1
TA = 25°C
1.248
0.8
100μA
0.7
5mA
1mA
0.6
0.5
0.4
0.3
0.2
0.1
1.247
–50 –30 –10 10 30 50 70
TEMPERATURE (°C)
90
0.1
110
0
0.5
1
1.5
2
INPUT-OUTPUT VOLTAGE (V)
17901.25 G02
17091.25 G01
Load Regulation (Sourcing)
–600
–800
–1000
TA = 25°C
TA = 125°C
–1200
–1400
–1600
–1800
–2000
0.1
100
1800
90
1600
80
1400
1200
1000
10
17901.25 G04
TA = –55°C
800
600
400
200
1
OUTPUT CURRENT (mA)
Supply Current vs Input Voltage
2000
SUPPLY CURRENT (μA)
TA = –55°C
–200
–400
17091.25 G03
Load Regulation (Sinking)
OUTPUT VOLTAGE CHANGE (ppm)
OUTPUT VOLTAGE CHANGE (ppm)
0
0
–50 –30 –10 10 30 50 70 90 110 130
TEMPERATURE (°C)
2.5
0
0.1
TA = 125°C
TA = –55°C
TA = 25°C
70
60
50
TA = 125°C
40
30
20
TA = 25°C
1
OUTPUT CURRENT (mA)
10
10
17901.25 G05
0
0
5
15
10
INPUT VOLTAGE (V)
20
17901.25 G06
1790fb
11
LT1790
1.25V TYPICAL PERFORMANCE CHARACTERISTICS
Each of the voltage options have similar performance curves. For the 3V, 3.3V and the 4.096V options,
the curves can be estimated based on the 2.5V and 5V curves.
Power Supply Rejection Ratio
vs Frequency
Line Regulation
500
TA = 125°C
–10
100
1.265
1.260
1.255
TA = 25°C
1.250
TA = –55°C
1.245
1.240
1.235
1.230
1.225
4
2
0
–20
–30
–40
–50
–60
10
CL = 4.7μF
CL = 1μF
1
–80
1k
10k
100k
FREQUENCY (Hz)
1M
0
100
1k
10k
FREQUENCY (Hz)
100k
17901.25 G09
17901.25 G08
17901.25. G07
Long-Term Drift
(Data Points Reduced After 500 Hr)
– 1.25V Characteristics
0.30
Output Noise 0.1Hz to 10Hz
140
LT1790S6-1.25V
120 2 TYPICAL PARTS SOLDERED TO PCB
TA = 30°C
100
R1 10k
3V
4
LT1790-1.25
CURRENT IN RL (mA)
1
0.20
0.15
6
2
80
VOUT
RL
5k
1μF
60
ppm
0.25
CL = 0.47μF
–70
–90
100
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
VIN = 3V
OUTPUT NOISE (5μV/DIV)
OUTPUT VOLTAGE (V)
1.275
1.270
VIN = 3V
0 CL = 1μF
OUTPUT IMPEDANCE (Ω)
POWER SUPPLY REJECTION RATIO (dB)
1.280
Output Impedance vs Frequency
10
1.285
–VEE
40
20
0.10
0
TA = 25°C
TA = 125°C
TA = –55°C
0.05
–20
–40
0
–2.5
–2.0
–1.5
–1.0
–0.5
OUTPUT TO GROUND VOLTAGE (V)
–60
0
200
0
600
400
HOURS
800
17091.25 G10
INTEGRATED NOISE (μVRMS)
NOISE VOLTAGE (μV/√Hz)
3.5
3.0
2.5
IO = 100μA
IO = 0μA
IO = 250μA
1.5
1.0
0.5
IO = 1mA
0
10
2
3
4 5 6
TIME (SEC)
7
8
9
10
17901.25 G12
Integrated Noise 10Hz to 1kHz
4.0
2.0
1
100
CL = 1μF
4.5
0
17901.25 G11
Output Voltage Noise Spectrum
5.0
1000
100
1k
FREQUENCY (Hz)
10
1
10k
17901.25 G13
10
100
FREQUENCY (Hz)
1000
17901.25 G14
1790fb
12
LT1790
2.048V TYPICAL PERFORMANCE CHARACTERISTICS
Each of the voltage options have similar performance curves. For the 3V, 3.3V and the 4.096V options,
the curves can be estimated based on the 2.5V and 5V curves.
Minimum Input-Output Voltage
Minimum Input-Output Voltage
Output Voltage Temperature Drift
Differential (Sourcing)
Differential (Sinking)
2.056
10
130
TA = 25°C
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
2.054
2.052
2.050
2.048
2.046
TA = 125°C
110
VOLTAGE DIFFERENTIAL (mV)
FOUR TYPICAL PARTS
TA = –55°C
1
2.044
0.1
0
0.1
0.2 0.3 0.4 0.5
0.6
INPUT-OUTPUT VOLTAGE (V)
17902.048 G01
5mA
50
1mA
30
10
100μA
–10
Load Regulation (Sinking)
–600
TA = 125°C
–800
–1000
–1200
–1400
–1600
80
1800
1
OUTPUT CURRENT (mA)
1400
1200
TA = –40°C
1000
800
600
TA = 125°C
400
1
OUTPUT CURRENT (mA)
20
2.050
TA = 25°C
TA = –55°C
2.046
2.044
2.042
0
2
4
30
TA = 125°C
20
10
0
10
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
17902.048 G07
0
10
5
10
20
15
INPUT VOLTAGE (V)
17902.048 G06
Output Impedance vs Frequency
1000
CL = 1μF
0
OUTPUT IMPEDANCE (Ω)
POWER SUPPLY REJECTION RATIO (dB)
2.054
TA = 125°C
TA = 25°C
40
Power Supply Rejection Ratio
vs Frequency
Line Regulation
2.048
50
17902.048 G05
17902.048 G04
2.052
60
TA = 25°C
0
0.1
10
TA = –55°C
70
1600
200
–1800
–2000
0.1
Supply Current vs Input Voltage
SUPPLY CURRENT (μA)
OUTPUT VOLTAGE CHANGE (ppm)
TA = 25°C
–400
17902.048 G03
2000
TA = –55°C
–200
–50
–50 –30 –10 10 30 50 70 90 110 130
TEMPERATURE (°C)
0.7
17902.048 G02
Load Regulation (Sourcing)
0
OUTPUT VOLTAGE CHANGE (ppm)
70
–30
2.042
–50 –30 –10 10 30 50 70 90 110 130
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
90
–10
–20
–30
–40
–50
CL = 0.47μF
100
10
CL = 4.7μF
CL = 1μF
–60
–70
–80
100
1k
10k
100k
FREQUENCY (Hz)
1M
17902.048 G08
1
10k
100k
1M
FREQUENCY (Hz)
10M
17902.048 G09
1790fb
13
LT1790
2.048V TYPICAL PERFORMANCE CHARACTERISTICS
Each of the voltage options have similar performance curves. For the 3V, 3.3V and the 4.096V options,
the curves can be estimated based on the 2.5V and 5V curves.
– 2.048V Characteristics
Long-Term Drift
0.30
100
TA = 30°C
80 2 TYPICAL PARTS SOLDERED TO PCB
R1 10k
3V
4
0.25
LT1790-2.048
CURRENT IN RL (mA)
1
0.20
40
VOUT
RL
5k
1μF
20
ppm
0.15
60
6
2
–VEE
0
–20
0.10
TA = 125°C
TA = 25°C
TA = –55°C
0.05
–40
–60
–80
–100
0
–4 –3.5 –3 –2.5 –2 –1.5 –1 –0.5
OUTPUT TO GROUND VOLTAGE (V)
0
200
0
600
400
HOURS
17092.048 G10
800
1000
17902.048 G11
Output Voltage Noise Spectrum
Output Noise 0.1Hz to 10Hz
10
CL = 1μF
NOISE VOLTAGE (μV/√Hz)
OUTPUT NOISE (10μV/DIV)
9
8
7
6
5
IO = 100μA
4
IO = 0μA
3
IO = 250μA
2
1
IO = 1mA
0
0
1
2
3
4 5 6
TIME (SEC)
7
8
9
10
10
100
1k
FREQUENCY (Hz)
10k
17902.048 G13
17902.048 G12
Integrated Noise 10Hz to 1kHz
INTEGRATED NOISE (μVRMS)
100
10
1
10
100
FREQUENCY (Hz)
1000
17902.048 G14
1790fb
14
LT1790
2.5 TYPICAL PERFORMANCE CHARACTERISTICS
Each of the voltage options have similar performance curves. For the 3V, 3.3V and the 4.096V options,
the curves can be estimated based on the 2.5V and 5V curves.
Minimum Input-Output Voltage
Differential (Sourcing)
Output Voltage Temperature Drift
2.508
Minimum Input-Output Voltage
Differential (Sinking)
90
10
FOUR TYPICAL PARTS
2.504
2.502
2.500
2.498
TA = –55°C
VOLTAGE DIFFERENTIAL (mV)
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
2.506
TA = 125°C
TA = 25°C
1
2.496
2.494
–50 –30 –10 10 30 50 70 90 110 130
TEMPERATURE (°C)
0.3
0.4
0.5
0.1
0.2
INPUT-OUTPUT VOLTAGE (V)
Load Regulation (Sourcing)
TA = 125°C
–800
–1000
–1200
–1400
–1600
Supply Current vs Input Voltage
70
1400
1200
1000
800
TA = –55°C
600
400
20
TA = 125°C
20
10
1
OUTPUT CURRENT (mA)
0
10
2.505
TA = 25°C
2.500
TA = –55°C
2.490
2.489
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
17902.5 G07
0
10
5
10
20
15
INPUT VOLTAGE (V)
17902.5 G06
Output Impedance vs Frequency
1000
CL = 1μF
CL = 0.47μF
0
OUTPUT IMPEDANCE (Ω)
POWER SUPPLY REJECTION RATIO (dB)
2.510
4
30
Power Supply Rejection Ratio
vs Frequency
2.515
2
TA = 25°C
40
17902.5 G05
Line Regulation
0
50
TA = 25°C
17902.5 G04
2.495
60
TA = 125°C
0
0.1
10
TA = 125°C
TA = –55°C
1600
200
1
OUTPUT CURRENT (mA)
–10
80
1800
–1800
–2000
0.1
1mA
5mA
17902.5 G03
SUPPLY CURRENT (μA)
OUTPUT VOLTAGE CHANGE (ppm)
OUTPUT VOLTAGE CHANGE (ppm)
TA = –55°C
–600
OUTPUT VOLTAGE (V)
0.6
2000
TA = 25°C
100μA
10
Load Regulation (Sinking)
0
–400
30
17902.5 G02
17902.5 G01
–200
50
–30
–50 –30 –10 10 30 50 70 90 110 130
TEMPERATURE (°C)
0.1
0
70
–10
–20
–30
–40
–50
CL = 1μF
100
CL = 4.7μF
10
–60
–70
–80
100
1k
10k
100k
FREQUENCY (Hz)
1M
17902.5 G08
1
100
1k
10k
FREQUENCY (Hz)
100k
17902.5 G09
1790fb
15
LT1790
2.5V TYPICAL PERFORMANCE CHARACTERISTICS
Each of the voltage options have similar performance curves. For the 3V, 3.3V and the 4.096V options,
the curves can be estimated based on the 2.5V and 5V curves.
Long-Term Drift
– 2.5V Characteristics
(Data Points Reduced After 500 Hr)
140
0.30
0.25
3V
LT1790-2.5
100
6
1, 2
0.20
0.15
80
VOUT
RL
5k
1μF
60
ppm
CURRENT IN RL (mA)
TA = 30°C
120 2 TYPICAL PARTS SOLDERED TO PCB
R1 10k
4
–VEE
40
20
0.10
0
TA = 25°C
TA = 125°C
TA = –55°C
0.05
–20
–40
0
–4.0 –3.5 –3.0 –2.5 –2.0 –1.5 –1.0 –0.5
OUTPUT TO GROUND VOLTAGE (V)
–60
0
200
0
600
400
HOURS
800
1000
17902.5 G11
17902.5 G10
Output Noise 0.1Hz to 10Hz
Output Voltage Noise Spectrum
NOISE VOLTAGE (μV/√Hz)
OUTPUT NOISE (10μV/DIV)
10
CL = 1μF
8
IO = 0μA
6
IO = 250μA
4
IO = 1mA
2
0
1
2
3
4 5 6
TIME (SEC)
7
8
9
0
10
10
100
1k
FREQUENCY (Hz)
10k
17902.5 G13
17902.5 G12
Integrated Noise 10Hz to 1kHz
INTEGRATED NOISE (μVRMS)
100
10
1
10
100
FREQUENCY (Hz)
1000
17902.5 G14
1790fb
16
LT1790
5V TYPICAL PERFORMANCE CHARACTERISTICS
Each of the voltage options have similar performance curves. For the 3V, 3.3V and the 4.096V options,
the curves can be estimated based on the 2.5V and 5V curves.
Minimum Input-Output Voltage
Differential (Sourcing)
Output Voltage Temperature Drift
5.025
Minimum Input-Output Voltage
Differential (Sinking)
90
10
FOUR TYPICAL PARTS
5.020
OUTPUT VOLTAGE (V)
5.015
5.010
5.005
5.000
4.995
VOLTAGE DIFFERENTIAL (mV)
OUTPUT CURRENT (mA)
70
TA = –55°C
TA = 125°C
TA = 25°C
1
50
100μA
30
–10
0
0.1
0.2
0.3
0.4
0.5
INPUT-OUTPUT VOLTAGE (V)
Load Regulation (Sourcing)
Load Regulation (Sinking)
TA = 25°C
–600
TA = 125°C
–800
–1000
–1200
–1400
–1600
1800
70
1400
1200
1000
TA = –40°C
800
600
400
0
0.1
10
20
5.02
TA = 25°C
TA = –55°C
4.96
4.94
4.92
2
4
20
10
1
OUTPUT CURRENT (mA)
0
10
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
17905 G07
0
10
5
10
20
15
INPUT VOLTAGE (V)
17905 G06
Output Impedance vs Frequency
1000
CL = 1μF
0
OUTPUT IMPEDANCE (Ω)
POWER SUPPLY REJECTION RATIO (dB)
TA = 125°C
TA = 125°C
30
Power Supply Rejection Ratio
vs Frequency
5.04
0
40
17905 G05
Line Regulation
4.98
TA = 25°C
50
TA = 25°C
17905 G04
5.00
60
TA = 125°C
200
1
OUTPUT CURRENT (mA)
TA = –55°C
1600
–1800
–2000
0.1
Supply Current vs Input Voltage
80
SUPPLY CURRENT (μA)
OUTPUT VOLTAGE CHANGE (ppm)
–400
17905 G03
2000
TA = –55°C
–200
0.6
17905 G02
17905 G01
0
–50
–50 –30 –10 10 30 50 70 90 110 130
TEMPERATURE (°C)
0.1
4.985
–50 –30 –10 10 30 50 70 90 110 130
TEMPERATURE (°C)
OUTPUT VOLTAGE CHANGE (ppm)
5mA
–30
4.990
OUTPUT VOLTAGE (V)
1mA
10
–10
–20
–30
–40
–50
CL = 0.47μF
100
CL = 1μF
CL = 4.7μF
10
–60
–70
–80
100
1k
10k
100k
FREQUENCY (Hz)
1M
17905 G08
1
100
1k
10k
FREQUENCY (Hz)
100k
17905 G09
1790fb
17
LT1790
5V TYPICAL PERFORMANCE CHARACTERISTICS
Each of the voltage options have similar performance curves. For the 3V, 3.3V and the 4.096V options,
the curves can be estimated based on the 2.5V and 5V curves.
Long-Term Drift
– 5V Characteristics
0.30
100
TA = 30°C
80 2 TYPICAL PARTS SOLDERED TO PCB
R1 10k
5.5V
4
0.25
LT1790-5
CURRENT IN RL (mA)
1
0.20
40
VOUT
RL
5k
1μF
20
ppm
0.15
60
6
2
–VEE
0
–20
0.10
–40
TA = 125°C
TA = 25°C
0.05
TA = –55°C
0
–10 –9 –8 –7 –6 –5 –4 –3 –2 –1
OUTPUT TO GROUND VOLTAGE (V)
–60
–80
0
–100
200
0
600
400
HOURS
800
17905 G10
1000
17905 G11
Output Noise 0.1Hz to 10Hz
Output Voltage Noise Spectrum
NOISE VOLTAGE (μV/√Hz)
OUTPUT NOISE (20μV/DIV)
10
CL = 1μF
8
IO = 0μA
6
IO = 250μA
4
IO = 1mA
2
0
1
2
3
4 5 6
TIME (SEC)
7
8
9
0
10
100
1k
FREQUENCY (Hz)
10
10k
17905 G13
17905 G12
Integrated Noise 10Hz to 1kHz
INTEGRATED NOISE (μVRMS)
1000
100
10
1
10
100
FREQUENCY (Hz)
1000
17905 G14
1790fb
18
LT1790
APPLICATIONS INFORMATION
Bypass and Load Capacitors
The LT1790 voltage references should have an input bypass
capacitor of 0.1μF or larger, however the bypassing of other
local devices may serve as the required component. These
references also require an output capacitor for stability.
The optimum output capacitance for most applications
is 1μF, although larger values work as well. This capacitor affects the turn-on and settling time for the output to
reach its final value.
All LT1790 voltages perform virtually the same, so the
LT1790-2.5 is used as an example.
Figure 1 shows the turn-on time for the LT1790-2.5 with a
1μF input bypass and 1μF load capacitor. Figure 2 shows
the output response to a 0.5V transient on VIN with the
same capacitors.
The test circuit of Figure 3 is used to measure the stability
of various load currents. With RL = 1k, the 1V step produces
a current step of 1mA. Figure 4 shows the response to a
± 0.5mA load. Figure 5 is the output response to a sourcing
step from 4mA to 5mA, and Figure 6 is the output response
of a sinking step from –4mA to –5mA.
VIN
VOUT
3V
VIN
VOUT
3V
2V
2V
1V
1V
0V
0V
1790 F01
1790 F02
Figure 2. Output Response to 0.5V Ripple on VIN
Figure 1. Turn-On Characteristics of LT1790-2.5
4
VIN
3V
CIN
0.1μF
LT1790-2.5
1k
6
CL
1μF
1, 2
VGEN
1V
1790 F03
Figure 3. Response Time Test Circuit
VGEN
3V
2V
VOUT
(AC COUPLED)
VOUT
(AC COUPLED)
VGEN
–2V
–3V
1790 F04
Figure 4. LT1790-2.5 Sourcing and Sinking 0.5mA
1790 F05
Figure 5. LT1790-2.5 Sourcing 4mA to 5mA
1790fb
19
LT1790
APPLICATIONS INFORMATION
Positive or Negative Operation
Series operation is ideal for extending battery life. If an
LT1790 is operated in series mode it does not require an
external current setting resistor. The specifications guarantee that the LT1790 family operates to 18V. When the
circuitry being regulated does not demand current, the
series connected LT1790 consumes only a few hundred
μW, yet the same connection can sink or source 5mA of
load current when demanded. A typical series connection
is shown on the front page of this data sheet.
The circuit in Figure 7 shows the connection for a – 2.5V
reference, although any LT1790 voltage option can be
configured this way to make a negative reference. The
LT1790 can be used as very stable negative references,
however, they require a positive voltage applied to Pin 4
to bias internal circuitry. This voltage must be current
limited with R1 to keep the output PNP transistor from
turning on and driving the grounded output. C1 provides
stability during load transients. This connection maintains
nearly the same accuracy and temperature coefficient of
the positive connected LT1790.
Long-Term Drift
Long-term drift cannot be extrapolated from accelerated
high temperature testing. This erroneous technique gives
drift numbers that are widely optimistic. The only way
long-term drift can be determined is to measure it over
the time interval of interest. The LT1790S6 drift data was
taken on over 100 parts that were soldered into PC boards
similar to a real world application. The boards were then
placed into a constant temperature oven with TA = 30°C,
their outputs scanned regularly and measured with an 8.5
digit DVM. Long-term drift curves are shown in the Typical
Performance Characteristics section.
VGEN
8V
R1
10k
3V
4
6V
6
VOUT
(AC COUPLED)
4V
LT1790-2.5
C1
0.1μF
1, 2
VOUT = –2.5V
2V
0V
V – VOUT
RL = EE
125μA
CL
1μF
VEE
1790 F07
1790 F06
Figure 6. LT1790-2.5 Sinking – 4mA to –5mA
Figure 7. Using the LT1790-2.5 to Build a –2.5V Reference
1790fb
20
LT1790
APPLICATIONS INFORMATION
Hysteresis
Hysteresis data shown in Figures 8 and 9 represent the
worst-case data taken on parts from 0°C to 70°C and from
– 40°C to 85°C. Units were cycled several times over these
temperature ranges and the largest change is shown. As
expected, the parts cycled over the higher temperature
range have higher hysteresis than those cycled over the
lower range.
In addition to thermal hysteresis, the thermal shock associated with high temperature soldering may cause the
output to shift. For traditional PbSn solder temperatures,
the output shift of the LT1790 is typically just 150ppm
(0.015%).
For lead-free solder, IR reflow temperatures are much
higher, often 240°C to 260°C at the peak. As a result, the
packaging materials have been optimized to reduce VOUT
shift as possible during high temperature reflow. In addition, care should be taken when using lead-free solder to
minimize the peak temperature and dwell time as much
as is practical. A typical lead-free reflow profile is shown
in Figure 10. LT1790 units were heated using a similar
profile, with a peak temperature of 250°C. These parts
were run through the heating process 3 times to show the
cumulative effect of these heat cycles. Figure 11 shows
300
380s
DEGREES (C)
NUMBER OF UNITS
25
20
TS(MAX) = 200°C
T = 190°C
70°C TO 25°C
tP
130s
T = 150°C
150
tL
130s
RAMP TO
150°C
0°C TO 25°C
15
RAMP
DOWN
TL = 217°C
225
30
TP = 260°
75
40s
120s
10
0
0
2
5
4
6
MINUTES
8
10
1790 F10
0
–60 –50 –40 –30 –20 –10 0 10 20
DISTRIBUTION (ppm)
30
40
50
Figure 10. Lead-Free Reflow Profile
60
1790 F08
Figure 8. Worst-Case 0°C to 70°C Hysteresis on 79 Units
9
8
50
7
NUMBER OF UNITS
45
NUMBER OF UNITS
40
35
30
25
80°C TO 25°C
6
5
4
3
2
20
–40°C TO 25°C
15
1
10
0
5
0
0
10
20
30
40
50
PPM
–100
–80 –60
–40
–20
0
20
40
DISTRIBUTION (ppm)
60
80
100
1790 F09
1790 F11
Figure 11. 1X IR Reflow Peak Temperature = 250°C,
Delta Output Voltage (ppm)
Figure 9. Worst-Case –40°C to 85°C Hysteresis on 80 Units
1790fb
21
LT1790
APPLICATIONS INFORMATION
the shift after 1 cycle, while Figure 12 shows shift after
3 cycles. In the worst case, shifts are typically 150ppm,
but may be as high as 290ppm. Shifts in output voltage
are proportional to temperature and dwell time.
In general, the output shift can be reduced or fully recovered by a long (12-24 hour) bake of the completed PC
Board assembly at high temperature (100°C to 150C°)
after soldering to remove mechanical stress that has been
induced by thermal shock. Once the PC Boards have cooled
to room temperature, they may continue to shift for up to
3 times the bake time. This should be taken into account
before any calibration is performed.
Assuming 80μA max supply current for the LT1790, a
25μA load, 120mV max dropout and a 4V to 30V input
specification, the largest that R1 can be is (4V – 3.3V
– 120mV)/(80μA + 25μA) = 5.5k. Furthermore, assuming 220mW of dissipation in the 18V SOT-23 Zener, this
gives a max current of (220mW)/(18V) = 12.2mA. So the
smallest that R1 should be is (30V – 18V)/12.2mA = 1k,
rated at 150mW.
With R1 = 1k, and assuming a 450mV worst-case dropout, the LT1790 can deliver a minimum current of (4V
– 3.3V–450mV)/(1k) = 250μA. In Figure 13, R1 and C1
provide filtering of the Zener noise when the Zener is in
its noisy V-I knee.
3.5
There are other variations for higher voltage operation that
use a pass transistor shown in Figures 14 and 15. These
circuits allow the input voltage to be as high as 160V while
maintaining low supply current.
NUMBER OF UNITS
3.0
2.5
2.0
1.5
1.0
R1
330k
VS
6V TO 160V
R2
4.7k
ON SEMI
MMBT5551
0.5
0
BZX84C12
70
90 110 130 150 170 190 210 230 250 270 290
PPM
C1
0.1μF
LT1790
VOUT
C2
1μF
1790 F12
Figure 12. 3X IR Reflow Peak Temperature = 250°C,
Delta Output Voltage (ppm)
Higher Input Voltage
1790 F14
Figure 14. Extended Supply Range Reference
The circuit in Figure 13 shows an easy way to increase the
input voltage range of the LT1790. The Zener diode can be
anywhere from 6V to 18V. For equal power sharing between
R1 and the Zener (at 30V), the 18V option is better. The
circuit can tolerate much higher voltages for short periods
and is suitable for transient protection.
ON SEMI
MMBT5551
R1
330k
C1
0.1μF
VS
6.5V TO 160V
BAV99
4V TO 30V
C2
1μF
VOUT
LT1790-3.3
BZX84C18
C1
0.1μF
VOUT
LT1790
R1
1790 F15
Figure 15. Extended Supply Range Reference
1μF
1790 F13
Figure 13. Extended Supply Range Reference
1790fb
22
LT1790
APPLICATIONS INFORMATION
More Output Current
The circuit in Figure 16 is a compact, high output current,
low dropout precision supply. The circuit uses the SOT-23
LT1782 and the ThinSOT LT1790. Resistive divider R1 and
R2 set a voltage 22mV below VS. For under 1mA of output
current, the LT1790 supplies the load. Above 1mA of load
current, the (+) input of the LT1782 is pulled below the
22mV divider reference and the output FET turns on to
supply the load current. Capacitor C1 stops oscillations in
the transition region. The no load standing current is only
120μA, yet the output can deliver over 300mA.
Noise
An estimate of the total integrated noise from 10Hz to 1kHz
can be made by multiplying the flat band spot noise by
√BW. For example, from the Typical Performance curves,
the LT1790-1.25 noise spectrum shows the average spot
noise to be about 450nV/√Hz. The square root of the
VS
2.8V TO 3.3V
NO LOAD
SUPPLY CURRENT
120μA
R1
680Ω
5%
R3
22Ω
5%
bandwidth is √990 = 31.4. The total noise 10Hz to 1kHz
noise is (450nV)(31.4) = 14.1μV. This agrees well with the
measured noise.
This estimate may not be as good with higher voltage
options, there are several reasons for this. Higher voltage
options have higher noise and they have higher variability
due to process variations. 10Hz to 1kHz noise may vary by
2dB on the LT1790-5 and 1dB on the LT1790-2.5.
Measured noise may also vary because of peaking in the
noise spectrum. This effect can be seen in the range of
1kHz to 10kHz with all voltage options sourcing different
load currents. From the Typical Performance curves the
10Hz to 1kHz noise spectrum of the LT1790-5 is shown
to be 3μV/√Hz at low frequency. The estimated noise is
(3μV)(31.4) = 93.4μV. The actual integrated 10Hz to 1kHz
noise measures 118.3μV. The peaking shown causes this
larger number. Peaking is a function of output capacitor
as well as load current and process variations.
R4
1k
5%
+
LT1782
–
R2
100k
5%
VISHAY SILICONIX
Si3445DV
C1
0.1μF
LT1790-2.5
C2
1μF
17909 F16
VOUT = 2.5V
ILOAD = 0mA to 300mA
NOTE: NOT CURRENT LIMITED
Figure 16. Compact, High Output Current, Low Dropout, Precision 2.5V Supply
1790fb
23
LT1790
SIMPLIFIED SCHEMATIC
4 VIN
6 VOUT
1, 2 GND
1790 SS
1790fb
24
LT1790
PACKAGE DESCRIPTION
S6 Package
6-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1636)
0.62
MAX
2.90 BSC
(NOTE 4)
0.95
REF
1.22 REF
3.85 MAX 2.62 REF
1.4 MIN
2.80 BSC
1.50 – 1.75
(NOTE 4)
PIN ONE ID
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.30 – 0.45
6 PLCS (NOTE 3)
0.95 BSC
0.80 – 0.90
0.20 BSC
0.01 – 0.10
1.00 MAX
DATUM ‘A’
0.30 – 0.50 REF
0.09 – 0.20
(NOTE 3)
1.90 BSC
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
S6 TSOT-23 0302 REV B
1790fb
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.
25
LT1790
TYPICAL APPLICATION
– 2.5V Negative 50mA Series Reference
No Load Supply Current
ICC = 1.6mA
IEE = 440μA
VCC = 5V
2k
4
LT1790-2.5
VZ = 5.1V
6
1, 2
5.1k
–2.5V
50mA
VEE = –5V
MPS2907A
1μF
1790 TA03
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1019
Precision Reference
Low Noise Bandgap, 0.05%, 5ppm/°C
LTC®1798
Micropower Low Dropout Reference
0.15% Max, 6.5μA Supply Current
LT1460
Micropower Precision Series Reference
Bandgap, 130μA Supply Current, 10ppm/°C, Available in SOT-23
LT1461
Micropower Precision Low Dropout Reference
Bandgap 0.04%, 3ppm/°C, 50μA Max Supply Current
1790fb
26 Linear Technology Corporation
LT 0609 REV B • PRINTED IN USA
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