LT1790ACS6-3.3#PBF [Linear]
LT1790 - Micropower SOT-23 Low Dropout Reference Family; Package: SOT; Pins: 6; Temperature Range: 0°C to 70°C;
| 型号： | LT1790ACS6-3.3#PBF |
| 厂家： | 
Linear |
| 描述： | LT1790 - Micropower SOT-23 Low Dropout Reference Family; Package: SOT; Pins: 6; Temperature Range: 0°C to 70°C 光电二极管 |
| 文件： | 总26页 (文件大小：309K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LT1790
Micropower SOT-23
Low Dropout Reference Family
FEATURES
DESCRIPTION
TheLT®1790isafamilyofSOT-23micropowerlowdropout
seriesreferencesthatcombinehighaccuracyandlowdrift
with low power dissipation and small package size. These
micropower references use curvature compensation to
obtain a low temperature coefficient and trimmed preci-
sionthin-filmresistorstoachievehighoutputaccuracy. In
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High Accuracy:
A Grade—0.05% Max
B Grade—0.1% Max
Low Drift:
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A Grade—10ppm/°C Max
B Grade—25ppm/°C Max
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n
n
n
n
n
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Low Thermal Hysteresis 40ppm (Typical) –40°C to 85°C
Low Supply Current: 60μA Max
addition, each LT1790 is post-package trimmed to greatly
reducethetemperaturecoefficientandincreasetheoutput
accuracy. Output accuracy is further assured by excellent
line and load regulation. Special care has been taken to
minimize thermally induced hysteresis.
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
The LT1790s are ideally suited for battery-operated sys-
tems because of their small size, low supply current and
reduced dropout voltage. These references provide sup-
ply current and power dissipation advantages over shunt
referencesthatmustidletheentireloadcurrenttooperate.
Since the LT1790 can also sink current, it can operate as
a micropower negative voltage reference with the same
performance as a positive reference.
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APPLICATIONS
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Handheld Instruments
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Negative Voltage References
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.
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Industrial Control Systems
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Data Acquisition Systems
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Battery-Operated Equipment
TYPICAL APPLICATION
Positive Connection for LT1790-2.5
Typical VOUT Distribution for LT1790-2.5
50
167 UNITS
4
6
45
V
= 2.5V
LT1790-2.5
1, 2
2.6V ≤ V ≤ 18V
OUT
IN
40
0.1μF
1μF
LT1790B LIMITS
35
LT1790A LIMITS
1790 TA01
30
25
20
15
10
5
0
2.498
2.499 2.500
2.501
2.502
OUTPUT VOLTAGE (V)
1790 TA02
1790fb
1
LT1790
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
(Note 1)
TOP VIEW
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
GND 1
GND 2
6 V
OUT
5 DNC*
DNC* 3
4 V
IN
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
T
= 150°C, θ = 230°C/W
JA
JMAX
(Note 2)..................................................–40°C to 125°C
Storage Temperature Range
*DNC: DO NOT CONNECT
(Note 3)..................................................–65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
LTXT
PACKAGE DESCRIPTION
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
SPECIFIED TEMPERATURE RANGE
0°C to 70°C
LT1790ACS6-1.25#PBF
LT1790AIS6-1.25#PBF
LT1790BCS6-1.25#PBF
LT1790BIS6-1.25#PBF
LT1790ACS6-2.048#PBF
LT1790AIS6-2.048#PBF
LT1790BCS6-2.048#PBF
LT1790BIS6-2.048#PBF
LT1790ACS6-2.5#PBF
LT1790AIS6-2.5#PBF
LT1790BCS6-2.5#PBF
LT1790BIS6-2.5#PBF
LT1790ACS6-3#PBF
LT1790AIS6-3#PBF
LT1790ACS6-1.25#TRPBF
LT1790AIS6-1.25#TRPBF
LT1790BCS6-1.25#TRPBF
LT1790BIS6-1.25#TRPBF
LT1790ACS6-2.048#TRPBF
LT1790AIS6-2.048#TRPBF
LT1790BCS6-2.048#TRPBF
LT1790BIS6-2.048#TRPBF
LT1790ACS6-2.5#TRPBF
LT1790AIS6-2.5#TRPBF
LT1790BCS6-2.5#TRPBF
LT1790BIS6-2.5#TRPBF
LT1790ACS6-3#TRPBF
LT1790AIS6-3#TRPBF
LTXT
–40°C to 85°C
0°C to 70°C
LTXT
LTXT
–40°C to 85°C
0°C to 70°C
LTXU
LTXU
LTXU
LTXU
LTPZ
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
LTPZ
–40°C to 85°C
0°C to 70°C
LTPZ
LTPZ
–40°C to 85°C
0°C to 70°C
LTQA
LTQA
LTQA
LTQA
LTXW
LTXW
LTXW
LTXW
LTQB
LTQB
LTQB
LTQB
LTQC
LTQC
LTQC
LTQC
–40°C to 85°C
0°C to 70°C
LT1790BCS6-3#PBF
LT1790BIS6-3#PBF
LT1790BCS6-3#TRPBF
LT1790BIS6-3#TRPBF
–40°C to 85°C
0°C to 70°C
LT1790ACS6-3.3#PBF
LT1790AIS6-3.3#PBF
LT1790BCS6-3.3#PBF
LT1790BIS6-3.3#PBF
LT1790ACS6-4.096#PBF
LT1790AIS6-4.096#PBF
LT1790BCS6-4.096#PBF
LT1790BIS6-4.096#PBF
LT1790ACS6-5#PBF
LT1790AIS6-5#PBF
LT1790ACS6-3.3#TRPBF
LT1790AIS6-3.3#TRPBF
LT1790BCS6-3.3#TRPBF
LT1790BIS6-3.3#TRPBF
LT1790ACS6-4.096#TRPBF
LT1790AIS6-4.096#TRPBF
LT1790BCS6-4.096#TRPBF
LT1790BIS6-4.096#TRPBF
LT1790ACS6-5#TRPBF
LT1790AIS6-5#TRPBF
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
LT1790BCS6-5#PBF
LT1790BIS6-5#PBF
LT1790BCS6-5#TRPBF
LT1790BIS6-5#TRPBF
–40°C to 85°C
1790fb
2
LT1790
ORDER INFORMATION
LEAD BASED FINISH
LT1790ACS6-1.25
LT1790AIS6-1.25
LT1790BCS6-1.25
LT1790BIS6-1.25
LT1790ACS6-2.048
LT1790AIS6-2.048
LT1790BCS6-2.048
LT1790BIS6-2.048
LT1790ACS6-2.5
LT1790AIS6-2.5
LT1790BCS6-2.5
LT1790BIS6-2.5
LT1790ACS6-3
TAPE AND REEL
PART MARKING*
LTXT
PACKAGE DESCRIPTION
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
SPECIFIED TEMPERATURE RANGE
0°C to 70°C
LT1790ACS6-1.25#TR
LT1790AIS6-1.25#TR
LT1790BCS6-1.25#TR
LT1790BIS6-1.25#TR
LT1790ACS6-2.048#TR
LT1790AIS6-2.048#TR
LT1790BCS6-2.048#TR
LT1790BIS6-2.048#TR
LT1790ACS6-2.5#TR
LT1790AIS6-2.5#TR
LT1790BCS6-2.5#TR
LT1790BIS6-2.5#TR
LT1790ACS6-3#TR
LT1790AIS6-3#TR
LTXT
–40°C to 85°C
0°C to 70°C
LTXT
LTXT
–40°C to 85°C
0°C to 70°C
LTXU
LTXU
LTXU
LTXU
LTPZ
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
LTPZ
–40°C to 85°C
0°C to 70°C
LTPZ
LTPZ
–40°C to 85°C
0°C to 70°C
LTQA
LTQA
LTQA
LTQA
LTXW
LTXW
LTXW
LTXW
LTQB
LTQB
LTQB
LTQB
LTQC
LTQC
LTQC
LTQC
LT1790AIS6-3
–40°C to 85°C
0°C to 70°C
LT1790BCS6-3
LT1790BCS6-3#TR
LT1790BIS6-3#TR
LT1790BIS6-3
–40°C to 85°C
0°C to 70°C
LT1790ACS6-3.3
LT1790AIS6-3.3
LT1790BCS6-3.3
LT1790BIS6-3.3
LT1790ACS6-4.096
LT1790AIS6-4.096
LT1790BCS6-4.096
LT1790BIS6-4.096
LT1790ACS6-5
LT1790ACS6-3.3#TR
LT1790AIS6-3.3#TR
LT1790BCS6-3.3#TR
LT1790BIS6-3.3#TR
LT1790ACS6-4.096#TR
LT1790AIS6-4.096#TR
LT1790BCS6-4.096#TR
LT1790BIS6-4.096#TR
LT1790ACS6-5#TR
LT1790AIS6-5#TR
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
LT1790AIS6-5
–40°C to 85°C
0°C to 70°C
LT1790BCS6-5
LT1790BCS6-5#TR
LT1790BIS6-5#TR
LT1790BIS6-5
–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/
1790fb
3
LT1790
AVAILABLE OPTIONS
TEMPERATURE RANGE
0°C TO 70°C
–40°C TO 85°C
OUTPUT
VOLTAGE
INITIAL
ACCURACY
TEMPERATURE
COEFFICIENT
ORDER PART NUMBER
ORDER PART NUMBER
1.250V
2.048V
2.500V
3.000V
3.300V
4.096V
5.000V
0.05%
0.1%
10ppm/°C
25ppm/°C
LT1790ACS6-1.25
LT1790BCS6-1.25
LT1790AIS6-1.25
LT1790BIS6-1.25
0.05%
0.1%
10ppm/°C
25ppm/°C
LT1790ACS6-2.048
LT1790BCS6-2.048
LT1790AIS6-2.048
LT1790BIS6-2.048
0.05%
0.1%
10ppm/°C
25ppm/°C
LT1790ACS6-2.5
LT1790BCS6-2.5
LT1790AIS6-2.5
LT1790BIS6-2.5
0.05%
0.1%
10ppm/°C
25ppm/°C
LT1790ACS6-3
LT1790BCS6-3
LT1790AIS6-3
LT1790BIS6-3
0.05%
0.1%
10ppm/°C
25ppm/°C
LT1790ACS6-3.3
LT1790BCS6-3.3
LT1790AIS6-3.3
LT1790BIS6-3.3
0.05%
0.1%
10ppm/°C
25ppm/°C
LT1790ACS6-4.096
LT1790BCS6-4.096
LT1790AIS6-4.096
LT1790BIS6-4.096
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
MIN
TYP
MAX
UNITS
Output Voltage (Notes 3, 4)
LT1790A
1.24937
–0.05
1.25
1.25062
0.05
V
%
LT1790B
LT1790AC
LT1790AI
LT1790BC
LT1790BI
1.24875
–0.1
1.25
1.25
1.25
1.25
1.25
1.25125
0.1
V
%
l
l
1.24850
–0.12
1.2515
0.12
V
%
l
l
1.24781
–0.175
1.25219
0.175
V
%
l
l
1.24656
–0.275
1.25344
0.275
V
%
l
l
1.24484
–0.4125
1.25516
0.4125
V
%
Output Voltage Temperature Coefficient (Note 5)
T
≤ T ≤ T
MIN A MAX
LT1790A
LT1790B
l
l
5
12
10
25
ppm/°C
ppm/°C
Line Regulation
2.6V ≤ V ≤ 18V
50
170
220
ppm/V
ppm/V
IN
l
l
l
Load Regulation (Note 6)
I
Source = 5mA, V = 2.8V
100
120
160
250
ppm/mA
ppm/mA
OUT
OUT
IN
I
Sink = 1mA, V = 3.2V
180
250
ppm/mA
ppm/mA
IN
Minimum Operating Voltage (Note 7)
V , ΔV
= 0.1%
OUT
IN
1.95
2.15
2.50
2.90
2.95
V
V
V
V
I
= 0mA
OUT
l
l
l
I
I
Source = 5mA
Sink = 1mA
OUT
OUT
1790fb
4
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
MIN
TYP
MAX
UNITS
Supply Current
No Load
35
60
75
μA
μA
l
Minimum Operating Current—
Negative Output (See Figure 7)
V
= –1.25V, 0.1%
100
250
125
μA
OUT
Turn-On Time
C
= 1μF
μs
LOAD
Output Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
10
14
μV
P-P
RMS
μV
Long-Term Drift of Output Voltage (Note 9)
Hysteresis (Note 10)
50
ppm/√kHr
l
l
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
25
40
ppm
ppm
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
MIN
TYP
MAX
UNITS
Output Voltage (Notes 3, 4)
LT1790A
2.04697
–0.05
2.048
2.04902
0.05
V
%
LT1790B
LT1790AC
LT1790AI
LT1790BC
LT1790BI
2.04595
–0.1
2.048
2.048
2.048
2.048
2.048
2.05005
0.1
V
%
l
l
2.04554
–0.12
2.05046
0.12
V
%
l
l
2.04442
–0.175
2.05158
0.175
V
%
l
l
2.04237
–0.275
2.05363
0.275
V
%
l
l
2.03955
–0.4125
2.05645
0.4125
V
%
Output Voltage Temperature Coefficient (Note 5)
T
≤ T ≤ T
MIN A MAX
LT1790A
LT1790B
l
l
5
12
10
25
ppm/°C
ppm/°C
Line Regulation
2.8V ≤ V ≤ 18V
50
170
220
ppm/V
ppm/V
IN
l
l
l
Load Regulation (Note 6)
I
Source = 5mA
Sink = 3mA
120
130
200
280
ppm/mA
ppm/mA
OUT
OUT
I
260
450
ppm/mA
ppm/mA
Dropout Voltage (Note 7)
Supply Current
V
– V , ΔV
OUT
= 0.1%
OUT
IN
OUT
50
100
500
750
450
mV
mV
mV
mV
I
= 0mA
l
l
l
I
I
Source = 5mA
Sink = 3mA
OUT
OUT
No Load
35
60
75
μA
μA
l
Minimum Operating Current—
Negative Output (See Figure 7)
V
C
= –2.048V, 0.1%
100
350
125
μA
OUT
Turn-On Time
= 1μF
μs
LOAD
1790fb
5
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
MIN
TYP
MAX
UNITS
μV
Output Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
22
41
P-P
μV
RMS
Long-Term Drift of Output Voltage (Note 9)
Hysteresis (Note 10)
50
ppm/√kHr
l
l
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
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
MIN
TYP
MAX
UNITS
Output Voltage (Notes 3, 4)
LT1790A
2.49875
–0.05
2.5
2.50125
0.05
V
%
LT1790B
LT1790AC
LT1790AI
LT1790BC
LT1790BI
2.4975
–0.1
2.5
2.5
2.5
2.5
2.5
2.5025
0.1
V
%
l
l
2.4970
–0.12
2.5030
0.12
V
%
l
l
2.49563
–0.175
2.50438
0.175
V
%
l
l
2.49313
–0.275
2.50688
0.275
V
%
l
l
2.48969
–0.4125
2.51031
0.4125
V
%
Output Voltage Temperature Coefficient (Note 5)
T
≤ T ≤ T
MIN A MAX
LT1790A
LT1790B
l
l
5
12
10
25
ppm/°C
ppm/°C
Line Regulation
3V ≤ V ≤ 18V
50
80
70
170
220
ppm/V
ppm/V
IN
l
l
l
Load Regulation (Note 6)
I
Source = 5mA
Sink = 3mA
160
250
ppm/mA
ppm/mA
OUT
OUT
I
110
300
ppm/mA
ppm/mA
Dropout Voltage (Note 7)
Supply Current
V
– V , ΔV
OUT
= 0.1%
OUT
IN
OUT
50
100
120
450
250
mV
mV
mV
mV
I
= 0mA
l
l
l
I
I
Source = 5mA
Sink = 3mA
OUT
OUT
No Load
35
60
80
μA
μA
l
Minimum Operating Current—
Negative Output (See Figure 7)
V
C
= –2.5V, 0.1%
100
700
125
μA
OUT
Turn-On Time
= 1μF
μs
LOAD
Output Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
32
48
μV
P-P
RMS
μV
Long-Term Drift of Output Voltage (Note 9)
Hysteresis (Note 10)
50
ppm/√kHr
l
l
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
25
40
ppm
ppm
1790fb
6
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
UNITS
Output Voltage (Notes 3, 4)
LT1790A
2.9985
–0.05
3
3.0015
0.05
V
%
LT1790B
LT1790AC
LT1790AI
LT1790BC
LT1790BI
2.9970
–0.10
3
3
3
3
3
3.0030
0.10
V
%
l
l
2.99640
–0.12
3.00360
0.12
V
%
l
l
2.99475
–0.175
3.00525
0.175
V
%
l
l
2.99175
–0.275
3.00825
0.275
V
%
l
l
2.98763
–0.4125
3.01238
0.4125
V
%
Output Voltage Temperature Coefficient (Note 5)
T
≤ T ≤ T
MIN A MAX
LT1790A
LT1790B
l
l
5
12
10
25
ppm/°C
ppm/°C
Line Regulation
3.5V ≤ V ≤ 18V
50
80
70
170
220
ppm/V
ppm/V
IN
l
l
l
Load Regulation (Note 6)
I
Source = 5mA
Sink = 3mA
160
250
ppm/mA
ppm/mA
OUT
OUT
I
110
300
ppm/mA
ppm/mA
Dropout Voltage (Note 7)
Supply Current
V
– V , ΔV
OUT
= 0.1%
OUT
IN
OUT
50
100
120
450
250
mV
mV
mV
mV
I
= 0mA
l
l
l
I
I
Source = 5mA
Sink = 3mA
OUT
OUT
No Load
35
60
80
μA
μA
l
Minimum Operating Current—
Negative Output (See Figure 7)
V
OUT
= –3V, 0.1%
100
125
μA
Turn-On Time
C
= 1μF
700
μs
LOAD
Output Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
50
56
μV
P-P
RMS
μV
Long-Term Drift of Output Voltage (Note 9)
Hysteresis (Note 10)
50
ppm/√kHr
l
l
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
25
40
ppm
ppm
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
UNITS
Output Voltage (Notes 3, 4)
LT1790A
3.29835
–0.05
3.3
3.30165
0.05
V
%
LT1790B
LT1790AC
LT1790AI
LT1790BC
LT1790BI
3.2967
–0.10
3.3
3.3
3.3
3.3
3.3
3.3033
0.10
V
%
l
l
3.29604
–0.120
3.30396
0.120
V
%
l
l
3.29423
–0.175
3.30578
0.175
V
%
l
l
3.29093
–0.275
3.30908
0.275
V
%
l
l
3.28639
–0.4125
3.31361
0.4125
V
%
Output Voltage Temperature Coefficient (Note 5)
T
≤ T ≤ T
MIN A MAX
LT1790A
LT1790B
l
l
5
12
10
25
ppm/°C
ppm/°C
Line Regulation
3.8V ≤ V ≤ 18V
50
80
70
170
220
ppm/V
ppm/V
IN
l
l
l
Load Regulation (Note 6)
I
Source = 5mA
Sink = 3mA
160
250
ppm/mA
ppm/mA
OUT
OUT
I
110
300
ppm/mA
ppm/mA
Dropout Voltage (Note 7)
Supply Current
V
– V , ΔV
OUT
= 0.1%
IN
OUT
OUT
50
100
120
450
250
mV
mV
mV
mV
I
= 0mA
l
l
l
I
I
Source = 5mA
Sink = 3mA
OUT
OUT
No Load
35
60
80
μA
μA
l
Minimum Operating Current—
Negative Output (See Figure 7)
V
OUT
= –3.3V, 0.1%
100
125
μA
Turn-On Time
C
= 1μF
700
μs
LOAD
Output Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
50
67
μV
P-P
RMS
μV
Long-Term Drift of Output Voltage (Note 9)
Hysteresis (Note 10)
50
ppm/√kHr
l
l
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
25
40
ppm
ppm
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
LT1790AC
LT1790AI
LT1790BC
LT1790BI
4.092
–0.10
4.096
4.096
4.096
4.096
4.096
4.10
0.10
V
%
l
l
4.09108
–0.120
4.10092
0.120
V
%
l
l
4.08883
–0.175
4.10317
0.175
V
%
l
l
4.08474
–0.275
4.10726
0.275
V
%
l
l
4.07910
–0.4125
4.11290
0.4125
V
%
Output Voltage Temperature Coefficient (Note 5)
T
≤ T ≤ T
MIN A MAX
LT1790A
LT1790B
l
l
5
12
10
25
ppm/°C
ppm/°C
Line Regulation
4.6V ≤ V ≤ 18V
50
80
70
170
220
ppm/V
ppm/V
IN
l
l
l
Load Regulation (Note 6)
I
Source = 5mA
Sink = 3mA
160
250
ppm/mA
ppm/mA
OUT
OUT
I
110
300
ppm/mA
ppm/mA
Dropout Voltage (Note 7)
Supply Current
V
– V , ΔV
OUT
= 0.1%
OUT
IN
OUT
50
100
120
450
250
mV
mV
mV
mV
I
= 0mA
l
l
l
I
I
Source = 5mA
Sink = 3mA
OUT
OUT
No Load
35
60
80
μA
μA
l
Minimum Operating Current—
Negative Output (See Figure 7)
V
= –4.096V, 0.1%
100
125
μA
OUT
Turn-On Time
C
= 1μF
700
μs
LOAD
Output Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
60
89
μV
P-P
RMS
μV
Long-Term Drift of Output Voltage (Note 9)
Hysteresis (Note 10)
50
ppm/√kHr
l
l
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
25
40
ppm
ppm
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
UNITS
Output Voltage (Notes 3, 4)
LT1790A
4.9975
–0.05
5
5.0025
0.05
V
%
LT1790B
LT1790AC
LT1790AI
LT1790BC
LT1790BI
4.995
–0.10
5
5
5
5
5
5.005
0.10
V
%
l
l
4.99400
–0.120
5.00600
0.120
V
%
l
l
4.99125
–0.175
5.00875
0.175
V
%
l
l
4.98625
–0.275
5.01375
0.275
V
%
l
l
4.97938
–0.4125
5.02063
0.4125
V
%
Output Voltage Temperature Coefficient (Note 5)
T
≤ T ≤ T
MIN A MAX
LT1790A
LT1790B
l
l
5
12
10
25
ppm/°C
ppm/°C
Line Regulation
5.5V ≤ V ≤ 18V
50
80
70
170
220
ppm/V
ppm/V
IN
l
l
l
Load Regulation (Note 6)
I
Source = 5mA
Sink = 3mA
160
250
ppm/mA
ppm/mA
OUT
OUT
I
110
300
ppm/mA
ppm/mA
Dropout Voltage (Note 7)
Supply Current
V
– V , ΔV
OUT
= 0.1%
OUT
IN
OUT
50
100
120
450
250
mV
mV
mV
mV
I
= 0mA
l
l
l
I
I
Source = 5mA
Sink = 3mA
OUT
OUT
No Load
35
60
80
μA
μA
l
Minimum Operating Current—
Negative Output (See Figure 7)
V
OUT
= –5V, 0.1%
100
125
μA
Turn-On Time
C
= 1μF
700
μs
LOAD
Output Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
80
118
μV
P-P
μV
RMS
Long-Term Drift of Output Voltage (Note 9)
Hysteresis (Note 10)
50
ppm/√kHr
l
l
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
25
40
ppm
ppm
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 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 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.
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 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.
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.
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)
Minimum Input-Output Voltage
Output Voltage Temperature Drift
Differential (Sinking)
10
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1.253
1.252
1.251
1.250
1.249
1.248
1.247
FOUR TYPICAL PARTS
100μA
1mA
5mA
T
= 125°C
T
T
= –55°C
= 25°C
A
A
A
1
0.1
50 70
–50 –30 –10 10 30
TEMPERATURE (°C)
90 110
0.5
1
1.5
2
2.5
0
–50 –30 –10 10 30 50 70 90 110 130
TEMPERATURE (°C)
INPUT-OUTPUT VOLTAGE (V)
17901.25 G02
17091.25 G01
17091.25 G03
Supply Current vs Input Voltage
Load Regulation (Sourcing)
Load Regulation (Sinking)
100
90
80
70
60
50
40
30
20
10
0
0
–200
2000
1800
1600
1400
1200
1000
800
T
= –55°C
A
T
= –55°C
A
–400
T
A
= 25°C
T
A
= 25°C
–600
–800
T
= –55°C
= 125°C
1
T
A
= 125°C
A
–1000
–1200
–1400
–1600
–1800
–2000
T
= 125°C
A
600
T
A
400
T
= 25°C
A
200
0
0.1
1
OUTPUT CURRENT (mA)
10
0.1
10
0
5
10
INPUT VOLTAGE (V)
15
20
OUTPUT CURRENT (mA)
17901.25 G04
17901.25 G05
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
Line Regulation
Output Impedance vs Frequency
vs Frequency
500
100
10
0
1.285
1.280
1.275
1.270
1.265
1.260
1.255
1.250
1.245
1.240
1.235
1.230
1.225
V
= 3V
V
C
= 3V
IN
IN
L
= 1μF
T
= 125°C
A
C
L
= 0.47μF
–10
–20
–30
–40
–50
–60
–70
–80
–90
10
1
C
= 4.7μF
L
T
= 25°C
A
C
= 1μF
L
T
= –55°C
A
0
100
1k
10k
100k
1M
0
2
4
6
8
10 12 14 16 18 20
100
1k
10k
100k
FREQUENCY (Hz)
FREQUENCY (Hz)
INPUT VOLTAGE (V)
17901.25 G09
17901.25 G08
17901.25. G07
Long-Term Drift
(Data Points Reduced After 500 Hr)
–1.25V Characteristics
Output Noise 0.1Hz to 10Hz
0.30
0.25
140
120
100
80
LT1790S6-1.25V
R1 10k
3V
2 TYPICAL PARTS SOLDERED TO PCB
4
T
= 30°C
A
LT1790-1.25
6
1
2
V
OUT
0.20
0.15
R
L
1μF
60
5k
–V
EE
40
20
0.10
0.05
0
0
T
T
T
= 25°C
= 125°C
= –55°C
A
A
A
–20
–40
–60
0
1
2
3
4
5
6
7
8
9
10
–2.5
–2.0
–1.5
–1.0
–0.5
0
0
200
400
600
800
1000
OUTPUT TO GROUND VOLTAGE (V)
TIME (SEC)
HOURS
17901.25 G12
17091.25 G10
17901.25 G11
Output Voltage Noise Spectrum
Integrated Noise 10Hz to 1kHz
5.0
4.5
4.0
3.5
100
10
1
C
= 1μF
L
3.0
2.5
I
= 100μA
= 0μA
O
2.0
1.5
1.0
0.5
0
I
O
I
= 250μA
O
I
O
= 1mA
10
100
1k
10k
10
100
1000
FREQUENCY (Hz)
FREQUENCY (Hz)
17901.25 G13
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
Differential (Sourcing)
Minimum Input-Output Voltage
Output Voltage Temperature Drift
Differential (Sinking)
2.056
2.054
2.052
2.050
2.048
2.046
2.044
2.042
10
130
110
90
FOUR TYPICAL PARTS
T
= 125°C
T
= 25°C
A
A
70
5mA
1mA
T
= –55°C
A
50
1
30
10
100μA
–10
–30
0.1
–50
–50 –30 –10 10 30 50
TEMPERATURE (°C)
130
70 90 110
0
0.1
0.2
INPUT-OUTPUT VOLTAGE (V)
0.7
0.3 0.4 0.5
0.6
–50 –30 –10 10
TEMPERATURE (°C)
90 110 130
30 50 70
17902.048 G01
17902.048 G02
17902.048 G03
Load Regulation (Sourcing)
Load Regulation (Sinking)
Supply Current vs Input Voltage
2000
1800
1600
1400
1200
1000
800
0
80
70
60
50
40
30
20
10
0
T
= –55°C
A
–200
–400
T
= –55°C
A
T
= 25°C
A
–600
T
A
= 125°C
T
= 25°C
–800
A
T
= –40°C
A
–1000
–1200
–1400
–1600
–1800
–2000
T
= 125°C
A
600
T
= 125°C
A
400
T
= 25°C
A
200
0
0.1
1
10
0.1
1
OUTPUT CURRENT (mA)
10
10
INPUT VOLTAGE (V)
0
5
15
20
OUTPUT CURRENT (mA)
17902.048 G05
17902.048 G04
17902.048 G06
Power Supply Rejection Ratio
vs Frequency
Line Regulation
Output Impedance vs Frequency
20
10
2.054
2.052
2.050
2.048
2.046
2.044
1000
100
10
C
= 1μF
L
T
T
= 125°C
= 25°C
A
0
C
= 0.47μF
L
–10
–20
–30
–40
–50
–60
–70
–80
A
T
= –55°C
A
C
= 4.7μF
= 1μF
L
C
L
2.042
1
0
2
4
6
8
10 12 14 16 18 20
100
1k
10k
100k
1M
10k
100k
1M
10M
FREQUENCY (Hz)
INPUT VOLTAGE (V)
FREQUENCY (Hz)
17902.048 G08
17902.048 G09
17902.048 G07
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
0.25
100
80
R1 10k
3V
4
LT1790-2.048
6
60
1
2
40
V
OUT
0.20
0.15
R
L
1μF
20
5k
–V
EE
0
–20
–40
–60
–80
–100
0.10
0.05
0
T
T
T
= 125°C
= 25°C
A
A
A
= –55°C
–4 –3.5 –3 –2.5 –2 –1.5 –1 –0.5
OUTPUT TO GROUND VOLTAGE (V)
0
0
200
400
600
800
1000
HOURS
17092.048 G10
17902.048 G11
Output Voltage Noise Spectrum
Output Noise 0.1Hz to 10Hz
10
9
C
= 1μF
L
8
7
6
5
I
= 100μA
O
4
3
2
1
0
I
= 0μA
O
I
= 250μA
O
I
= 1mA
1k
O
0
1
2
3
4
5
6
7
8
9
10
10
100
10k
TIME (SEC)
FREQUENCY (Hz)
17902.048 G13
17902.048 G12
Integrated Noise 10Hz to 1kHz
100
10
1
10
100
1000
FREQUENCY (Hz)
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)
Minimum Input-Output Voltage
Differential (Sinking)
Output Voltage Temperature Drift
2.508
2.506
2.504
2.502
2.500
2.498
2.496
2.494
90
70
10
FOUR TYPICAL PARTS
T
= –55°C
T = 125°C
A
A
50
T
= 25°C
A
30
10
1
100μA
1mA
5mA
–10
–30
0.1
50
TEMPERATURE (°C)
90
130
110
–50 –30 –10 10
90
110 130
30
70
0
0.1
0.2
0.3
0.4
0.5
0.6
–50 –30 –10 10 30 50 70
TEMPERATURE (°C)
INPUT-OUTPUT VOLTAGE (V)
17902.5 G02
17902.5 G01
17902.5 G03
Load Regulation (Sourcing)
Load Regulation (Sinking)
Supply Current vs Input Voltage
0
–200
2000
1800
1600
1400
1200
1000
800
80
70
60
50
40
30
20
10
0
T
= 25°C
A
T
= –55°C
A
–400
T
= –55°C
A
–600
T
= 125°C
A
–800
T
= 25°C
A
–1000
–1200
–1400
–1600
–1800
–2000
T
= –55°C
A
T
= 125°C
600
A
400
T
A
= 125°C
200
T
= 25°C
A
0
0.1
1
OUTPUT CURRENT (mA)
10
0.1
1
10
10
0
5
15
20
OUTPUT CURRENT (mA)
INPUT VOLTAGE (V)
17902.5 G04
17902.5 G05
17902.5 G06
Power Supply Rejection Ratio
vs Frequency
Line Regulation
Output Impedance vs Frequency
1000
100
10
20
10
2.515
2.510
2.505
2.500
2.495
2.490
C
= 1μF
L
T
= 125°C
A
C
= 0.47μF
L
0
C
= 1μF
L
–10
–20
–30
–40
–50
–60
–70
–80
T
= 25°C
A
C
= 4.7μF
L
T
= –55°C
A
1
2.489
100
1k
10k
100k
0
2
4
6
8
10 12 14 16 18 20
100
1k
10k
100k
1M
FREQUENCY (Hz)
INPUT VOLTAGE (V)
FREQUENCY (Hz)
17902.5 G09
17902.5 G08
17902.5 G07
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
(Data Points Reduced After 500 Hr)
–2.5V Characteristics
140
120
100
80
0.30
0.25
0.20
0.15
0.10
0.05
0
R1 10k
3V
4
LT1790-2.5
1, 2
6
V
OUT
R
L
5k
1μF
60
–V
40
EE
20
0
T
T
T
= 25°C
= 125°C
= –55°C
A
A
A
–20
–40
–60
0
200
400
600
800
1000
–4.0 –3.5 –3.0 –2.5 –2.0 –1.5 –1.0 –0.5
OUTPUT TO GROUND VOLTAGE (V)
0
HOURS
17902.5 G11
17902.5 G10
Output Noise 0.1Hz to 10Hz
Output Voltage Noise Spectrum
10
8
C
= 1μF
L
I
= 0μA
O
6
I
= 250μA
O
4
I
= 1mA
O
2
0
0
1
2
3
4
5
6
7
8
9
10
10
100
FREQUENCY (Hz)
1k
10k
TIME (SEC)
17902.5 G13
17902.5 G12
Integrated Noise 10Hz to 1kHz
100
10
1
10
100
1000
FREQUENCY (Hz)
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)
Minimum Input-Output Voltage
Differential (Sinking)
Output Voltage Temperature Drift
90
70
10
5.025
5.020
5.015
5.010
5.005
5.000
4.995
4.990
4.985
FOUR TYPICAL PARTS
50
T
= –55°C
A
100μA
1mA
T
A
= 125°C
A
30
T
= 25°C
1
10
–10
–30
–50
5mA
0.1
–50 –30 –10 10 30 50
110 130
70 90
30 50
0
0.1
0.2
0.3
0.4
0.5
0.6
–50 –30 –10 10
70 90 110 130
INPUT-OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
17905 G02
17905 G03
17905 G01
Load Regulation (Sourcing)
Load Regulation (Sinking)
Supply Current vs Input Voltage
0
–200
2000
1800
1600
1400
1200
1000
800
80
70
60
50
40
30
20
10
0
T
= –55°C
A
T
= –55°C
= 25°C
A
–400
T
= 25°C
A
–600
T
A
T
A
= 125°C
–800
–1000
–1200
–1400
–1600
–1800
–2000
T
= –40°C
A
T
= 125°C
A
600
400
T
= 125°C
A
200
T
= 25°C
A
0
0.1
1
OUTPUT CURRENT (mA)
10
0.1
1
10
10
INPUT VOLTAGE (V)
0
5
15
20
OUTPUT CURRENT (mA)
17905 G04
17905 G05
17905 G06
Power Supply Rejection Ratio
vs Frequency
Line Regulation
Output Impedance vs Frequency
20
10
5.04
5.02
5.00
4.98
4.96
4.94
1000
100
10
C
= 1μF
L
T
T
= 125°C
= 25°C
A
0
C
= 0.47μF
L
A
–10
–20
–30
–40
–50
–60
–70
–80
C
= 1μF
L
T
= –55°C
A
C
= 4.7μF
L
4.92
1
0
2
4
6
8
10 12 14 16 18 20
100
1k
10k
100k
1M
100
1k
10k
100k
INPUT VOLTAGE (V)
FREQUENCY (Hz)
FREQUENCY (Hz)
17905 G08
17905 G09
17905 G07
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
0.25
100
80
T
= 30°C
R1 10k
5.5V
4
A
2 TYPICAL PARTS SOLDERED TO PCB
LT1790-5
6
60
1
2
40
V
OUT
0.20
0.15
R
L
1μF
20
5k
–V
EE
0
–20
–40
–60
–80
–100
0.10
0.05
0
T
= 125°C
A
T
A
= 25°C
T
= –55°C
A
–10 –9 –8 –7 –6 –5 –4 –3 –2 –1
OUTPUT TO GROUND VOLTAGE (V)
0
0
200
400
600
800
1000
HOURS
17905 G10
17905 G11
Output Noise 0.1Hz to 10Hz
Output Voltage Noise Spectrum
10
8
C
= 1μF
L
I
= 0μA
O
6
I
O
= 250μA
4
I
= 1mA
O
2
0
0
1
2
3
4
5
6
7
8
9
10
10
100
FREQUENCY (Hz)
1k
10k
TIME (SEC)
17905 G13
17905 G12
Integrated Noise 10Hz to 1kHz
1000
100
10
1
10
100
1000
FREQUENCY (Hz)
17905 G14
1790fb
18
LT1790
APPLICATIONS INFORMATION
Bypass and Load Capacitors
Figure 1 shows the turn-on time for the LT1790-2.5 with a
1μF input bypass and 1μF load capacitor. Figure 2 shows
TheLT1790voltagereferencesshouldhaveaninputbypass
capacitorof0.1μForlarger,howeverthebypassingofother
localdevicesmayserveastherequiredcomponent. 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 capaci-
tor affects the turn-on and settling time for the output to
reach its final value.
the output response to a 0.5V transient on V with the
IN
same capacitors.
The test circuit of Figure 3 is used to measure the stability
ofvariousloadcurrents.WithR =1k,the1Vstepproduces
L
a current step of 1mA. Figure 4 shows the response to a
0.5mAload.Figure5istheoutputresponsetoasourcing
stepfrom4mAto5mA,andFigure 6istheoutputresponse
of a sinking step from –4mA to –5mA.
All LT1790 voltages perform virtually the same, so the
LT1790-2.5 is used as an example.
V
V
V
V
3V
2V
1V
0V
3V
2V
1V
0V
IN
OUT
IN
OUT
1790 F01
1790 F02
Figure 1. Turn-On Characteristics of LT1790-2.5
Figure 2. Output Response to 0.5V Ripple on VIN
1k
4
6
V
IN
LT1790-2.5
1, 2
3V
C
C
L
1μF
IN
V
1V
GEN
0.1μF
1790 F03
Figure 3. Response Time Test Circuit
V
GEN
3V
2V
V
V
OUT
OUT
(AC COUPLED)
(AC COUPLED)
V
–2V
GEN
–3V
1790 F05
1790 F04
Figure 4. LT1790-2.5 Sourcing and Sinking 0.5mA
Figure 5. LT1790-2.5 Sourcing 4mA to 5mA
1790fb
19
LT1790
APPLICATIONS INFORMATION
Positive or Negative Operation
turning on and driving the grounded output. C1 provides
stabilityduringloadtransients.Thisconnectionmaintains
nearly the same accuracy and temperature coefficient of
the positive connected LT1790.
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 guar-
antee 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.
Long-Term Drift
Long-termdriftcannotbeextrapolatedfromaccelerated
hightemperaturetesting.Thiserroneoustechniquegives
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
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
placed into a constant temperature oven with T = 30°C,
A
their outputs scanned regularly and measured with an 8.5
digitDVM. Long-termdriftcurvesareshownintheTypical
Performance Characteristics section.
V
GEN
8V
R1
10k
3V
4
6V
4V
2V
0V
6
C1
0.1μF
LT1790-2.5
1, 2
V
OUT
(AC COUPLED)
V
OUT
= –2.5V
V
EE
– V
OUT
125μA
C
L
R
=
L
1μF
V
EE
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
For lead-free solder, IR reflow temperatures are much
higher, often 240°C to 260°C at the peak. As a result, the
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°Cto85°C. Unitswerecycledseveraltimesoverthese
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.
packaging materials have been optimized to reduce V
OUT
shift as possible during high temperature reflow. In addi-
tion, 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
In addition to thermal hysteresis, the thermal shock as-
sociated 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%).
300
380s
T
= 260°
P
RAMP
DOWN
T = 217°C
L
225
150
30
25
20
T
= 200°C
S(MAX)
T = 190°C
t
P
130s
T = 150°C
t
L
130s
RAMP TO
150°C
0°C TO 25°C
70°C TO 25°C
15
75
0
40s
120s
10
5
0
2
4
6
8
10
MINUTES
1790 F10
0
–60 –50 –40 –30 –20 –10
0
10 20 30 40 50 60
Figure 10. Lead-Free Reflow Profile
DISTRIBUTION (ppm)
1790 F08
Figure 8. Worst-Case 0°C to 70°C Hysteresis on 79 Units
9
8
7
6
5
4
3
50
45
40
35
30
25
80°C TO 25°C
2
1
20
–40°C TO 25°C
15
10
5
0
0
10
20
30
40
50
PPM
0
1790 F11
–100 –80 –60 –40 –20
0
20
40
60
80 100
DISTRIBUTION (ppm)
Figure 11. 1X IR Reflow Peak Temperature = 250°C,
Delta Output Voltage (ppm)
1790 F09
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.
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, assum-
ing 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.
In general, the output shift can be reduced or fully recov-
ered 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
inducedbythermalshock.OncethePCBoardshavecooled
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.
With R1 = 1k, and assuming a 450mV worst-case drop-
out, 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
3.0
2.5
2.0
1.5
1.0
Thereareothervariationsforhighervoltageoperationthat
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.
V
S
6V TO 160V
R1
330k
R2
4.7k
ON SEMI
MMBT5551
0.5
BZX84C12
0
70 90 110 130 150 170 190 210 230 250 270 290
C1
0.1μF
LT1790
V
OUT
PPM
C2
1μF
1790 F12
Figure 12. 3X IR Reflow Peak Temperature = 250°C,
Delta Output Voltage (ppm)
1790 F14
Figure 14. Extended Supply Range Reference
Higher Input Voltage
The circuit in Figure 13 shows an easy way to increase the
input voltage range of the LT1790. The Zener diode can be
anywherefrom6Vto18V.Forequalpowersharingbetween
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.
V
S
6.5V TO 160V
C1
R1
330k
0.1μF
ON SEMI
MMBT5551
BAV99
4V TO 30V
R1
V
LT1790
OUT
C2
1μF
1790 F15
V
LT1790-3.3
OUT
C1
0.1μF
BZX84C18
1μF
Figure 15. Extended Supply Range Reference
1790 F13
Figure 13. Extended Supply Range Reference
1790fb
22
LT1790
APPLICATIONS INFORMATION
More Output Current
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.
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
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.
R2 set a voltage 22mV below V . For under 1mA of output
S
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.
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.
Noise
Anestimateofthetotalintegratednoisefrom10Hzto1kHz
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
V
S
2.8V TO 3.3V
NO LOAD
SUPPLY CURRENT
120μA
R3
22Ω
5%
R4
1k
5%
R1
+
680Ω
5%
VISHAY SILICONIX
Si3445DV
LT1782
–
C1
0.1μF
R2
100k
5%
V
I
= 2.5V
= 0mA to 300mA
OUT
LOAD
LT1790-2.5
17909 F16
C2
1μF
NOTE: NOT CURRENT LIMITED
Figure 16. Compact, High Output Current, Low Dropout, Precision 2.5V Supply
1790fb
23
LT1790
SIMPLIFIED SCHEMATIC
V
V
4
6
IN
OUT
GND
1, 2
1790 SS
1790fb
24
LT1790
PACKAGE DESCRIPTION
S6 Package
6-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1636)
2.90 BSC
(NOTE 4)
0.62
MAX
0.95
REF
1.22 REF
1.4 MIN
1.50 – 1.75
2.80 BSC
3.85 MAX 2.62 REF
(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
DATUM ‘A’
0.01 – 0.10
1.00 MAX
0.30 – 0.50 REF
1.90 BSC
0.09 – 0.20
(NOTE 3)
S6 TSOT-23 0302 REV B
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
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 representa-
tion 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
I
CC = 1.6mA
IEE = 440μA
V
= 5V
CC
2k
4
6
LT1790-2.5
1, 2
V
Z
= 5.1V
5.1k
–2.5V
50mA
V
EE
= –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
Micropower Precision Series Reference
0.15% Max, 6.5μA Supply Current
LT1460
LT1461
Bandgap, 130μA Supply Current, 10ppm/°C, Available in SOT-23
Bandgap 0.04%, 3ppm/°C, 50μA Max Supply Current
Micropower Precision Low Dropout Reference
1790fb
LT 0609 REV B • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
26
●
●
© LINEAR TECHNOLOGY CORPORATION 2000
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
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