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LT 1790 BCS6-2.5
Datasheet
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ANALOG DEVICES LT 1790 BCS6-2.5 Datasheet

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Page 1
LT1790
0.1μF
2.6V ≤ V
IN
≤ 18V
1μF
1, 2
6
V
OUT
= 2.5V
4
LT1790-2.5
1790 TA01
Micropower SOT-23
Low Dropout Reference Family
FEATURES
n
High Accuracy:
A Grade—0.05% Max
B Grade—0.1% Max
n
Low Drift:
A Grade—10ppm/°C Max B Grade—25ppm/°C Max
n
Low Thermal Hysteresis 40ppm (Typical) –40°C to 85°C
n
Low Supply Current: 60μA Max
n
Sinks and Sources Current
n
Low Dropout Voltage
n
Guaranteed Operational –40°C to 125°C
n
Wide Supply Range to 18V
n
Available Output Voltage Options: 1.25V, 2.048V,
2.5V, 3V, 3.3V, 4.096V and 5V
n
Low Profi le (1mm) ThinSOT™ Package
n
Handheld Instruments
n
Negative Voltage References
n
Industrial Control Systems
n
Data Acquisition Systems
n
Battery-Operated Equipment
DESCRIPTION
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 coeffi cient and trimmed preci­sion thin-fi lm resistors to achieve high output accuracy. In addition, each LT1790 is post-package trimmed to greatly reduce the temperature coeffi cient 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.
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
Typical V
50
167 UNITS
45
40
35
30
25
20
NUMBER OF UNITS
15
10
5
0
2.498 2.499 2.500 2.501 2.502
Distribution for LT1790-2.5Positive Connection for LT1790-2.5
OUT
LT1790B LIMITS
LT1790A LIMITS
OUTPUT VOLTAGE (V)
1790 TA02
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LT1790
PIN CONFIGURATION ABSOLUTE MAXIMUM RATINGS
(Note 1)
Input Voltage .............................................................20V
Specifi ed Temperature Range
Commercial............................................. 0°C to 70°C
Industrial .............................................– 40°C to 85°C
Output Short-Circuit Duration .......................... Indefi nite
Operating Temperature Range
(Note 2) ..................................................–40°C to 125°C
Storage Temperature Range
GND GND
DNC*
TOP VIEW
1 2 3
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
T
= 150°C, θJA = 230°C/W
JMAX
*DNC: DO NOT CONNECT
6 5 4
V
OUT
DNC* V
IN
(Note 3) ..................................................–65°C to 150°C
Lead Temperature (Soldering, 10 sec) ..................300°C
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
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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 specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container. For more information on lead free part marking, go to:
For more information on tape and reel specifi cations, go to:
http://www.linear.com/leadfree/
http://www.linear.com/tapeandreel/
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LT1790
AVAILABLE OPTIONS
OUTPUT
VOLTAGE
1.250V 0.05%
2.048V 0.05%
2.500V 0.05%
3.000V 0.05%
3.300V 0.05%
4.096V 0.05%
5.000V 0.05%
INITIAL
ACCURACY
0.1%
0.1%
0.1%
0.1%
0.1%
0.1%
0.1%
TEMPERATURE
COEFFICIENT
10ppm/°C 25ppm/°C
10ppm/°C 25ppm/°C
10ppm/°C 25ppm/°C
10ppm/°C 25ppm/°C
10ppm/°C 25ppm/°C
10ppm/°C 25ppm/°C
10ppm/°C 25ppm/°C
TEMPERATURE RANGE
0°C TO 70°C –40°C TO 85°C
ORDER PART NUMBER ORDER PART NUMBER
LT1790ACS6-1.25 LT1790BCS6-1.25
LT1790ACS 6-2.048 LT1790BCS6-2.048
LT1790ACS 6-2.5 LT1790BCS6-2.5
LT1790ACS 6-3 LT1790BCS6-3
LT1790ACS 6-3.3 LT1790BCS6-3.3
LT1790ACS 6-4.0 96 LT1790BCS6-4.096
LT1790ACS 6-5 LT1790BCS6-5
LT1790AIS6-1.25 LT1790BIS6-1.25
LT1790AIS6-2.048 LT1790BIS6-2.048
LT1790AIS6-2.5 LT1790BIS6-2.5
LT1790AIS6-3 LT1790BIS6-3
LT1790AIS6-3.3 LT1790BIS6-3.3
LT1790AIS6-4.09 6 LT1790BIS6-4.096
LT1790AIS6-5 LT1790BIS6-5
The l denotes the specifi cations which apply over the specifi ed
1.25V ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifi cations 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
LT1790B 1.24875
LT1790AC
LT1790AI
LT1790BC
LT1790BI
Output Voltage Temperature Coeffi cient (Note 5) T
Line Regulation 2.6V ≤ V
Load Regulation (Note 6) I
Minimum Operating Voltage (Note 7) VIN, ΔV
≤ TA ≤ T
MIN
LT1790A
LT1790B
Source = 5mA, VIN = 2.8V
OUT
I
Sink = 1mA, VIN = 3.2V
OUT
I
OUT
I
OUT
I
OUT
MAX
≤ 18V
IN
= 0.1%
OUT
= 0mA
Source = 5mA Sink = 1mA
–0.05
–0.1
l
1.24850
l
–0.12
l
1.24781
l
–0.175
l
1.24656
l
–0.275
l
1.24484
l
–0.4125
l l
l
l
l
l l l
1.25 1.25062
1.25 1.25125
1.25 1.2515
1.25 1.25219
1.25 1.25344
1.25 1.25516
5
12 50 170
100 160
120 180
1.95 2.15
0.05
0.1
0.12
0.175
0.275
0.4125
10 25
220
250
250
2.50
2.90
2.95
%
%
%
%
%
%
ppm/°C ppm/°C
ppm/V ppm/V
ppm/mA ppm/mA
ppm/mA ppm/mA
V
V
V
V
V
V
V V V V
4
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LT1790
The l denotes the specifi cations which apply over the specifi ed
1.25V ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifi cations are at T
PARAMETER CONDITIONS MIN TYP MAX UNITS
Supply Current No Load
Minimum Operating Current—
V
Negative Output (See Figure 7) Turn-On Time C Output Noise (Note 8) 0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz Long-Term Drift of Output Voltage (Note 9) 50 ppm/√kHr Hysteresis (Note 10) ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
The l denotes the specifi cations which apply over the
2.048V ELECTRICAL CHARACTERISTICS
specifi ed temperature range, otherwise specifi cations 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
LT1790B 2.04595
LT1790AC
LT1790AI
LT1790BC
LT1790BI
Output Voltage Temperature Coeffi cient (Note 5) T
LT1790B Line Regulation 2.8V ≤ V
Load Regulation (Note 6) I
I
Dropout Voltage (Note 7) V
Supply Current No Load
Minimum Operating Current— Negative Output (See Figure 7)
Turn-On Time C
I
I
I
V
= 25°C. CL = 1μF and VIN = 2.6V, unless otherwise noted.
A
35 60
l
= –1.25V, ±0.1% 100 125 μA
OUT
= 1μF 250 μs
LOAD
75
10 14
l l
25 40
2.048 2.04902
–0.05
0.05
2.048 2.05005
≤ TA ≤ T
MIN
LT1790A
IN
Source = 5mA
OUT
Sink = 3mA
OUT
– V
IN
OUT
= 0mA
OUT
Source = 5mA
OUT
Sink = 3mA
OUT
MAX
≤ 18V
, ΔV
OUT
= 0.1%
–0.1
l
2.04554
l
–0.12
l
2.04442
l
–0.175
l
2.04237
l
–0.275
l
2.03955
l
–0.4125
l l
2.048 2.05046
2.048 2.05158
2.048 2.05363
2.048 2.05645
5
12 50 170
l
120 200
l
130 260
l
50 100
l l l
0.1
0.12
0.175
0.275
0.4125
10 25
220
280
450
500 750 450
35 60
l
= –2.048V, 0.1% 100 125 μA
OUT
= 1μF 350 μs
LOAD
75
μA μA
μV
P-P
μV
RMS
ppm ppm
%
%
%
%
%
%
ppm/°C ppm/°C
ppm/V ppm/V
ppm/mA ppm/mA
ppm/mA ppm/mA
mV mV mV mV
μA μA
V
V
V
V
V
V
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LT1790
The l denotes the specifi cations which apply over the
2.048V ELECTRICAL CHARACTERISTICS
specifi ed temperature range, otherwise specifi cations are at T
PARAMETER CONDITIONS MIN TYP MAX UNITS
Output Noise (Note 8) 0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz Long-Term Drift of Output Voltage (Note 9) 50 ppm/√kHr Hysteresis (Note 10) ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
The l denotes the specifi cations which apply over the specifi ed
2.5V ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifi cations 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
LT1790B 2.4975
LT1790AC
LT1790AI
LT1790BC
LT1790BI
Output Voltage Temperature Coeffi cient (Note 5) T
Line Regulation 3V ≤ V
Load Regulation (Note 6) I
Dropout Voltage (Note 7) VIN – V
Supply Current No Load
Minimum Operating Current— Negative Output (See Figure 7)
Turn-On Time C Output Noise (Note 8) 0.1Hz ≤ f ≤ 10Hz
Long-Term Drift of Output Voltage (Note 9) 50 ppm/√kHr Hysteresis (Note 10) ΔT = 0°C to 70°C
≤ TA ≤ T
MIN
LT1790A
LT1790B
≤ 18V
IN
Source = 5mA
OUT
I
Sink = 3mA
OUT
, ΔV
OUT
I
= 0mA
OUT
I
Source = 5mA
OUT
I
Sink = 3mA
OUT
V
= –2.5V, 0.1% 100 125 μA
OUT
= 1μF 700 μs
LOAD
10Hz ≤ f ≤ 1kHz
ΔT = –40°C to 85°C
= 25°C. CL = 1μF and VIN = 2.8V, unless otherwise noted.
A
22 41
l l
25 40
2.5 2.50125
–0.05
2.5 2.5025
–0.1
l
MAX
2.4970
l
–0.12
l
2.49563
l
–0.175
l
2.49313
l
–0.275
l
2.48969
l
–0.4125
l l
2.5 2.5030
2.5 2.50438
2.5 2.50688
2.5 2.51031
5
12 50 170
l
80 160
l
70 110
l
= 0.1%
OUT
l l l
50 100
35 60
l
32 48
l l
25 40
0.05
0.1
0.12
0.175
0.275
0.4125
10 25
220
250
300
120 450 250
80
μV
P-P
μV
RMS
ppm ppm
%
%
%
%
%
%
ppm/°C ppm/°C
ppm/V ppm/V
ppm/mA ppm/mA
ppm/mA ppm/mA
mV mV mV mV
μA μA
μV
P-P
μV
RMS
ppm ppm
V
V
V
V
V
V
6
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LT1790
The l denotes the specifi cations which apply over the specifi ed
3V ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifi cations are at T
PARAMETER CONDITIONS MIN TYP MAX UNITS
Output Voltage (Notes 3, 4) LT1790A 2.9985
LT1790B 2.9970
LT1790AC
LT1790AI
LT1790BC
LT1790BI
Output Voltage Temperature Coeffi cient (Note 5) T
LT1790B Line Regulation 3.5V ≤ V
Load Regulation (Note 6) I
I
Dropout Voltage (Note 7) VIN – V
Supply Current No Load
Minimum Operating Current— Negative Output (See Figure 7)
Turn-On Time C Output Noise (Note 8) 0.1Hz ≤ f ≤ 10Hz
Long-Term Drift of Output Voltage (Note 9) 50 ppm/√kHr Hysteresis (Note 10) ΔT = 0°C to 70°C
I
I
I
V
10Hz ≤ f ≤ 1kHz
ΔT = –40°C to 85°C
= 25°C. CL = 1μF and VIN = 3.5V, unless otherwise noted.
A
3 3.0015
–0.05
0.05
3 3.0030
≤ TA ≤ T
MIN
LT1790A
IN
Source = 5mA
OUT
Sink = 3mA
OUT
OUT
= 0mA
OUT
Source = 5mA
OUT
Sink = 3mA
OUT
MAX
≤ 18V
, ΔV
OUT
= 0.1%
l l
l l
l l
l l
l l
l
l
l
l l l
–0.10
2.99640 –0.12
2.99475
–0.175
2.99175
–0.275
2.98763
–0.4125
3 3.00360
3 3.00525
3 3.00825
3 3.01238
5
12 50 170
80 160
70 110
50 100
0.10
0.12
0.175
0.275
0.4125
10 25
220
250
300
120 450 250
35 60
l
= –3V, 0.1% 100 125 μA
OUT
= 1μF 700 μs
LOAD
80
50 56
l l
25 40
%
%
%
%
%
%
ppm/°C ppm/°C
ppm/V ppm/V
ppm/mA ppm/mA
ppm/mA ppm/mA
mV mV mV mV
μA μA
μV
P-P
μV
RMS
ppm ppm
V
V
V
V
V
V
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LT1790
The l denotes the specifi cations which apply over the specifi ed
3.3V ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifi cations are at T
PARAMETER CONDITIONS MIN TYP MAX UNITS
Output Voltage (Notes 3, 4) LT1790A 3.29835
LT1790B 3.2967
LT1790AC
LT1790AI
LT1790BC
LT1790BI
Output Voltage Temperature Coeffi cient (Note 5) T
LT1790B
Line Regulation 3.8V ≤ V
Load Regulation (Note 6) I
I
Dropout Voltage (Note 7) VIN – V
Supply Current No Load
Minimum Operating Current— Negative Output (See Figure 7)
Turn-On Time C Output Noise (Note 8) 0.1Hz ≤ f ≤ 10Hz
Long-Term Drift of Output Voltage (Note 9) 50 ppm/√kHr Hysteresis (Note 10) ΔT = 0°C to 70°C
I
I I
V
10Hz ≤ f ≤ 1kHz
ΔT = –40°C to 85°C
= 25°C. CL = 1μF and VIN = 3.8V, unless otherwise noted.
A
3.3 3.30165
–0.05
0.05
3.3 3.3033
≤ TA ≤ T
MIN
LT1790A
IN
Source = 5mA
OUT
Sink = 3mA
OUT
OUT
= 0mA
OUT
Source = 5mA
OUT
Sink = 3mA
OUT
MAX
≤ 18V
, ΔV
OUT
= 0.1%
–0.10
l
3.29604
l
–0.120
l
3.29423
l
–0.175
l
3.29093
l
–0.275
l
3.28639
l
–0.4125
l l
3.3 3.30396
3.3 3.30578
3.3 3.30908
3.3 3.31361
5
12 50 170
l
80 160
l
70 110
l
50 100
l l l
0.10
0.120
0.175
0.275
0.4125
10 25
220
250
300
120 450 250
35 60
l
= –3.3V, 0.1% 100 125 μA
OUT
= 1μF 700 μs
LOAD
80
50 67
l l
25 40
%
%
%
%
%
%
ppm/°C ppm/°C
ppm/V ppm/V
ppm/mA ppm/mA
ppm/mA ppm/mA
mV mV mV mV
μA μA
μV
P-P
μV
RMS
ppm ppm
V
V
V
V
V
V
8
1790fb
Page 9
LT1790
The l denotes the specifi cations which apply over the
4.096V ELECTRICAL CHARACTERISTICS
specifi ed temperature range, otherwise specifi cations are at T
PARAMETER CONDITIONS MIN TYP MAX UNITS
Output Voltage (Notes 3, 4) LT1790A 4.094
LT1790B 4.092
LT1790AC
LT1790AI
LT1790BC
LT1790BI
Output Voltage Temperature Coeffi cient (Note 5) T
Line Regulation 4.6V ≤ V
Load Regulation (Note 6) I
Dropout Voltage (Note 7) VIN – V
Supply Current No Load
Minimum Operating Current— Negative Output (See Figure 7)
Turn-On Time C Output Noise (Note 8) 0.1Hz ≤ f ≤ 10Hz
Long-Term Drift of Output Voltage (Note 9) 50 ppm/√kHr Hysteresis (Note 10) ΔT = 0°C to 70°C
≤ TA ≤ T
MIN
LT1790A
LT1790B
≤ 18V
IN
Source = 5mA
OUT
I
Sink = 3mA
OUT
, ΔV
OUT
I
= 0mA
OUT
I
Source = 5mA
OUT
I
Sink = 3mA
OUT
= –4.096V, 0.1% 100 125 μA
V
OUT
= 1μF 700 μs
LOAD
10Hz ≤ f ≤ 1kHz
ΔT = –40°C to 85°C
= 25°C. CL = 1μF and VIN = 4.6V, unless otherwise noted.
A
4.096 4.098
–0.05
4.096 4.10
–0.10
l
MAX
4.09108
l
–0.120
l
4.08883
l
–0.175
l
4.08474
l
–0.275
l
4.07910
l
–0.4125
l l
4.096 4.10092
4.096 4.10317
4.096 4.10726
4.096 4.11290
5
12 50 170
l
80 160
l
70 110
l
= 0.1%
OUT
l l l
50 100
35 60
l
60 89
l l
25 40
0.05
0.10
0.120
0.175
0.275
0.4125
10 25
220
250
300
120 450 250
80
%
%
%
%
%
%
ppm/°C ppm/°C
ppm/V ppm/V
ppm/mA ppm/mA
ppm/mA ppm/mA
mV mV mV mV
μA μA
μV
P-P
μV
RMS
ppm ppm
V
V
V
V
V
V
1790fb
9
Page 10
LT1790
The l denotes the specifi cations which apply over the specifi ed
5V ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifi cations are at T
PARAMETER CONDITIONS MIN TYP MAX UNITS
Output Voltage (Notes 3, 4) LT1790A 4.9975
LT1790B 4.995
LT1790AC
LT1790AI
LT1790BC
LT1790BI
Output Voltage Temperature Coeffi cient (Note 5) T
LT1790B
Line Regulation 5.5V ≤ V
Load Regulation (Note 6) I
I
Dropout Voltage (Note 7) VIN – V
Supply Current No Load
Minimum Operating Current— Negative Output (See Figure 7)
Turn-On Time C Output Noise (Note 8) 0.1Hz ≤ f ≤ 10Hz
Long-Term Drift of Output Voltage (Note 9) 50 ppm/√kHr Hysteresis (Note 10) ΔT = 0°C to 70°C
I
I I
V
10Hz ≤ f ≤ 1kHz
ΔT = –40°C to 85°C
= 25°C. CL = 1μF and VIN = 5.5V, unless otherwise noted.
A
5 5.0025
–0.05
0.05
5 5.005
≤ TA ≤ T
MIN
LT1790A
IN
Source = 5mA
OUT
Sink = 3mA
OUT
OUT
= 0mA
OUT
Source = 5mA
OUT
Sink = 3mA
OUT
MAX
≤ 18V
, ΔV
OUT
= 0.1%
–0.10
l
4.99400
l
–0.120
l
4.99125
l
–0.175
l
4.98625
l
–0.275
l
4.97938
l
–0.4125
l l
5 5.00600
5 5.00875
5 5.01375
5 5.02063
5
12 50 170
l
80 160
l
70 110
l
50 100
l l l
0.10
0.120
0.175
0.275
0.4125
10 25
220
250
300
120 450 250
35 60
l
= –5V, 0.1% 100 125 μA
OUT
= 1μF 700 μs
LOAD
80
80
118
l l
25 40
ppm/°C ppm/°C
ppm/V ppm/V
ppm/mA ppm/mA
ppm/mA ppm/mA
mV mV mV mV
μA μA
μV
P-P
μV
RMS
ppm ppm
V
%
V
%
V
%
V
%
V
%
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: 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 specifi ed temperature range, the output voltage may shift due to hysteresis.
10
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 coeffi cient is measured by dividing the change in output voltage by the specifi ed 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 specifi ed load current. Output changes due to die temperature change must be taken into account separately.
Note 7: Excludes load regulation errors.
1790fb
Page 11
ELECTRICAL CHARACTERISTICS
LT1790
Note 8: Peak-to-peak noise is measured with a single pole highpass fi lter at 0.1Hz and a 2-pole lowpass fi lter 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
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.
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.
Output Voltage Temperature Drift
1.253 FOUR TYPICAL PARTS
1.252
1.251
1.250
1.249
OUTPUT VOLTAGE (V)
1.248
1.247
–50
–10 30
–30 10
TEMPERATURE (°C)
50
Minimum Input-Output Voltage Differential (Sourcing)
10
TA = 125°C TA = –55°C
1
OUTPUT CURRENT (mA)
70
90
17091.25 G01
110
0.1
0.5 2.521.51
0
INPUT-OUTPUT VOLTAGE (V)
TA = 25°C
17901.25 G02
Minimum Input-Output Voltage Differential (Sinking)
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
VOLTAGE DIFFERENTIAL (V)
0.2
0.1
0
–30 10
–50
–10
30
TEMPERATURE (°C)
5mA100μA
1mA
90
50 130
110
70
17091.25 G03
Load Regulation (Sourcing)
0
–200
–400
–600
–800
–1000
–1200
–1400
–1600
OUTPUT VOLTAGE CHANGE (ppm)
–1800
–2000
0.1
T
= 125°C
A
OUTPUT CURRENT (mA)
Load Regulation (Sinking)
TA = –55°C
= 25°C
T
A
110
17901.25 G04
2000
1800
1600
1400
1200
1000
800
600
400
OUTPUT VOLTAGE CHANGE (ppm)
200
0
0.1
TA = –55°C
= 125°C
T
A
OUTPUT CURRENT (mA)
110
T
A
= 25°C
17901.25 G05
Supply Current vs Input Voltage
100
90
80
70
60
50
40
30
SUPPLY CURRENT (μA)
20
10
TA = –55°C
T
A
0
0
5
10
INPUT VOLTAGE (V)
T
= 25°C
A
= 125°C
15
17901.25 G06
11
20
1790fb
Page 12
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
1.285
1.280
1.275
1.270
1.265
1.260
1.255
1.250
1.245
OUTPUT VOLTAGE (V)
1.240
1.235
1.230
1.225 4
218
0
T
= 125°C
A
T
= 25°C
A
TA = –55°C
6 INPUT VOLTAGE (V)
12
8
10
14
16
20
17901.25. G07
–1.25V Characteristics
0.30
0.25
0.20
(mA)
L
0.15
0.10
CURRENT IN R
0.05
0
R1 10k
4
LT1790-1.25
–V
OUTPUT TO GROUND VOLTAGE (V)
3V
6
21
V
OUT
R
L
1μF
5k
EE
–2.0 –1.5 –1.0 –0.5
TA = 25°C
= 125°C
T
A
= –55°C
T
A
17091.25 G10
0–2.5
vs Frequency
10
VIN = 3V
0
= 1μF
C
L
–10
–20
–30
–40
–50
–60
–70
–80
POWER SUPPLY REJECTION RATIO (dB)
–90
100 10k 100k 1M
1k
FREQUENCY (Hz)
17901.25 G08
500
VIN = 3V
100
10
1
OUTPUT IMPEDANCE (Ω)
0
100 10k 100k
CL = 4.7μF
CL = 1μF
1k FREQUENCY (Hz)
Long-Term Drift (Data Points Reduced After 500 Hr) Output Noise 0.1Hz to 10Hz
140
LT1790S6-1.25V 2 TYPICAL PARTS SOLDERED TO PCB
120
= 30°C
T
A
100
80
60
40
ppm
20
–20
–40
–60
0
200
0
400
HOURS
600
800
1000
17901.25 G11
OUTPUT NOISE (5μV/DIV)
0
246 107135 9
TIME (SEC)
CL = 0.47μF
17901.25 G09
8
17901.25 G12
12
Output Voltage Noise Spectrum Integrated Noise 10Hz to 1kHz
5.0 CL = 1μF
4.5
4.0
3.5
3.0
2.5
2.0
1.5
NOISE VOLTAGE (μV/√Hz)
1.0
0.5
0
10
100 1k 10k
FREQUENCY (Hz)
IO = 100μA
IO = 0μA
IO = 250μA
IO = 1mA
17901.25 G13
)
RMS
INTEGRATED NOISE (μV
100
10
1
10010 1000
FREQUENCY (Hz)
17901.25 G14
1790fb
Page 13
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.
Output Voltage Temperature Drift
2.056 FOUR TYPICAL PARTS
2.054
2.052
2.050
2.048
2.046
OUTPUT VOLTAGE (V)
2.044
2.042
–30 –10 10 30 50 130
–50
TEMPERATURE (°C)
70 90 110
17902.048 G01
Minimum Input-Output Voltage Differential (Sourcing)
10
TA = 25°C
1
OUTPUT CURRENT (mA)
0.1 0
0.1 INPUT-OUTPUT VOLTAGE (V)
0.4 0.5 0.6
0.3
TA = 125°C
TA = –55°C
0.70.2
17902.048 G02
Minimum Input-Output Voltage Differential (Sinking)
130
110
90
70
50
30
10
–10
VOLTAGE DIFFERENTIAL (mV)
–30
–50
–30 90
–50
LT1790
5mA
1mA
100μA
10 130
–10 110
TEMPERATURE (°C)
70
50
30
17902.048 G03
Load Regulation (Sourcing)
0
–200
–400
–600
–800
–1000
–1200
–1400
–1600
OUTPUT VOLTAGE CHANGE (ppm)
–1800
–2000
0.1
TA = 25°C
T
= 125°C
A
OUTPUT CURRENT (mA)
TA = –55°C
110
17902.048 G04
Load Regulation (Sinking) Supply Current vs Input Voltage
2000
1800
1600
1400
1200
1000
800
600
400
OUTPUT VOLTAGE CHANGE (ppm)
200
0
0.1 OUTPUT CURRENT (mA)
T
110
TA = –40°C
= 125°C
A
= 25°C
T
A
17902.048 G05
80
70
60
50
40
30
SUPPLY CURRENT (μA)
20
10
0
0
5
INPUT VOLTAGE (V)
10
Power Supply Rejection Ratio
Line Regulation Output Impedance vs Frequency
2.054
2.052
2.050
2.048
2.046
OUTPUT VOLTAGE (V)
2.044
2.042 4 8 12 16
INPUT VOLTAGE (V)
TA = 125°C
TA = 25°C
TA = –55°C
2020 6 10 14 18
17902.048 G07
vs Frequency
20
CL = 1μF
10
0
–10
–20
–30
–40
–50
–60
–70
POWER SUPPLY REJECTION RATIO (dB)
–80
100 10k 100k 1M
1k
FREQUENCY (Hz)
17902.048 G08
1000
100
10
OUTPUT IMPEDANCE (Ω)
1
10k
CL = 4.7μF
CL = 1μF
100k 1M 10M
FREQUENCY (Hz)
TA = –55°C
TA = 25°C
TA = 125°C
15
CL = 0.47μF
20
17902.048 G06
17902.048 G09
1790fb
13
Page 14
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
0.20
(mA)
L
0.15
0.10
CURRENT IN R
0.05
0
R1 10k
4
LT1790-2.048
–V
–3.5 –3 –2.5 –2 –1.5 –1 –0.5
OUTPUT TO GROUND VOLTAGE (V)
3V
6
21
V
OUT
R
L
1μF
5k
EE
TA = 125°C
= 25°C
T
A
= –55°C
T
A
17092.048 G10
0–4
100
TA = 30°C 2 TYPICAL PARTS SOLDERED TO PCB
80
60
40
20
0
ppm
–20
–40
–60
–80
–100
200
0
400
HOURS
600
800
17902.048 G11
1000
Output Noise 0.1Hz to 10Hz
OUTPUT NOISE (10μV/DIV)
0
246 107135 9
TIME (SEC)
100
)
RMS
NOISE VOLTAGE (μV/√Hz)
8
17902.048 G12
Integrated Noise 10Hz to 1kHz
10
Output Voltage Noise Spectrum
10
CL = 1μF
9
8
7
6 5
4
3
2
1
0
10
IO = 100μA
IO = 0μA
IO = 250μA
IO = 1mA
100 1k 10k
FREQUENCY (Hz)
17902.048 G13
14
INTEGRATED NOISE (μV
1
10010 1000
FREQUENCY (Hz)
17902.048 G14
1790fb
Page 15
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 (Sinking)
90
70
50
30
10
VOLTAGE DIFFERENTIAL (mV)
–10
Output Voltage Temperature Drift
2.508 FOUR TYPICAL PARTS
2.506
2.504
2.502
2.500
2.498
OUTPUT VOLTAGE (V)
2.496
Minimum Input-Output Voltage Differential (Sourcing)
10
TA = –55°C TA = 125°C
TA = 25°C
1
OUTPUT CURRENT (mA)
LT1790
100μA
1mA
5mA
2.494
–50
–30 –10
10
30 70
TEMPERATURE (°C)
Load Regulation (Sourcing)
0
–200
–400
–600
–800
–1000
–1200
–1400
–1600
OUTPUT VOLTAGE CHANGE (ppm)
–1800
–2000
0.1
TA = 25°C
T
= 125°C
A
OUTPUT CURRENT (mA)
110
50 90
TA = –55°C
110
17902.5 G01
17902.5 G04
130
0.1 0 0.1 0.2
Load Regulation (Sinking) Supply Current vs Input Voltage
2000
1800
1600
1400
1200
1000
800
600
400
OUTPUT VOLTAGE CHANGE (ppm)
200
0
0.1
INPUT-OUTPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
0.3 0.4 0.5 0.6
TA = –55°C
T
= 125°C
A
T
= 25°C
A
110
17902.5 G02
17902.5 G05
–30
–30 10
–50
–10
TEMPERATURE (°C)
80
70
60
50
40
30
SUPPLY CURRENT (μA)
20
10
0
0
5
INPUT VOLTAGE (V)
50 130
30
TA = –55°C
TA = 25°C
TA = 125°C
10
Power Supply Rejection Ratio
Line Regulation Output Impedance vs Frequency
2.515
2.510
2.505
2.500
2.495
OUTPUT VOLTAGE (V)
2.490
2.489
TA = 125°C
TA = 25°C
TA = –55°C
4 8 12 16
INPUT VOLTAGE (V)
2020 6 10 14 18
17902.5 G07
vs Frequency
20
CL = 1μF
10
0
–10
–20
–30
–40
–50
–60
–70
POWER SUPPLY REJECTION RATIO (dB)
–80
100 10k 100k 1M
1k
FREQUENCY (Hz)
17902.5 G08
1000
100
100
CL = 4.7μF
1k 10k 100k
FREQUENCY (Hz)
10
OUTPUT IMPEDANCE (Ω)
1
CL = 0.47μF
70
CL = 1μF
90
110
17902.5 G03
15
20
17902.5 G06
17902.5 G09
1790fb
15
Page 16
LT1790
OUTPUT TO GROUND VOLTAGE (V)
0
0
CURRENT IN R
L
(mA)
0.05
0.10
0.15
0.20
–1.0–2.0–3.0
–4.0
17902.5 G10
0.25
0.30
–0.5–1.5–2.5
–3.5
TA = 25°C T
A
= 125°C
T
A
= –55°C
–V
EE
V
OUT
3V
R
L
5k
4
1, 2
6
1μF
LT1790-2.5
R1 10k
HOURS
0
ppm
60
100
140
800
17902.5 G11
20
–20
40
80
120
0
–40
–60
200
400
600
1000
TA = 30°C 2 TYPICAL PARTS SOLDERED TO PCB
FREQUENCY (Hz)
10
NOISE VOLTAGE (μV/√Hz)
10
8
6
4
2
0
100 1k 10k
17902.5 G13
CL = 1μF
IO = 0μA
IO = 1mA
IO = 250μA
FREQUENCY (Hz)
1
INTEGRATED NOISE (μV
RMS
)
10
100
10010 1000
17902.5 G14
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
Output Noise 0.1Hz to 10Hz Output Voltage Noise Spectrum
(Data Points Reduced After 500 Hr)
16
OUTPUT NOISE (10μV/DIV)
0
246 107135 9
8
TIME (SEC)
17902.5 G12
Integrated Noise 10Hz to 1kHz
1790fb
Page 17
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.
Output Voltage Temperature Drift
5.025 FOUR TYPICAL PARTS
5.020
5.015
5.010
5.005
5.000
OUTPUT VOLTAGE (V)
4.995
4.990
4.985
–30 130
–50
–10
30
50
10
TEMPERATURE (°C)
Minimum Input-Output Voltage Differential (Sourcing)
10
TA = –55°C
TA = 125°C
1
OUTPUT CURRENT (mA)
0.1
110
70
90
17905 G01
0 0.1 0.2
INPUT-OUTPUT VOLTAGE (V)
TA = 25°C
0.3 0.4 0.5 0.6
17905 G02
Minimum Input-Output Voltage Differential (Sinking)
90
70
50
30
10
–10
VOLTAGE DIFFERENTIAL (mV)
–30
–50
–50
–30
LT1790
–10 30
10 50 130110
TEMPERATURE (°C)
5mA
70
100μA
1mA
90
17905 G03
Load Regulation (Sourcing)
0
–200
–400
–600
–800
–1000
–1200
–1400
–1600
OUTPUT VOLTAGE CHANGE (ppm)
–1800
–2000
0.1
TA = 25°C
= 125°C
T
A
OUTPUT CURRENT (mA)
110
TA = –55°C
17905 G04
Load Regulation (Sinking) Supply Current vs Input Voltage
2000
1800
1600
1400
1200
1000
800
600
400
OUTPUT VOLTAGE CHANGE (ppm)
200
0
0.1
TA = 125°C
110
OUTPUT CURRENT (mA)
TA = –40°C
TA = 25°C
17905 G05
80
70
60
50
40
30
SUPPLY CURRENT (μA)
20
10
0
0
5
INPUT VOLTAGE (V)
10
Power Supply Rejection Ratio
Line Regulation Output Impedance vs Frequency
5.04 TA = 125°C
5.02
5.00
4.98
4.96
OUTPUT VOLTAGE (V)
4.94
4.92
4 8 12 16
INPUT VOLTAGE (V)
TA = 25°C
TA = –55°C
2020 6 10 14 18
17905 G07
vs Frequency
20
CL = 1μF
10
0
–10
–20
–30
–40
–50
–60
–70
POWER SUPPLY REJECTION RATIO (dB)
–80
100 10k 100k 1M
1k
FREQUENCY (Hz)
17905 G08
1000
100
10
OUTPUT IMPEDANCE (Ω)
1
100
CL = 4.7μF
1k 10k 100k
FREQUENCY (Hz)
CL = 0.47μF
TA = –55°C
TA = 25°C
TA = 125°C
15
CL = 1μF
20
17905 G06
17905 G09
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17
Page 18
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.
–5V Characteristics
0.30
0.25
0.20
(mA)
L
0.15
0.10
CURRENT IN R
0.05
0
R1 10k
4
LT1790-5
21
R
L
5k
–V
EE
–8 –6 –4 –2
OUTPUT TO GROUND VOLTAGE (V)
5.5V
6
V
OUT
1μF
T
= 125°C
T
A
= 25°C
A
TA = –55°C
0–9–10 –7 –5 –3 –1
17905 G10
Long-Term Drift
100
TA = 30°C 2 TYPICAL PARTS SOLDERED TO PCB
80
60
40
20
0
ppm
–20
–40
–60
–80
–100
200
0
400
HOURS
600
Output Noise 0.1Hz to 10Hz Output Voltage Noise Spectrum
10
CL = 1μF
8
6
4
IO = 0μA
IO = 250μA
800
1000
17905 G11
OUTPUT NOISE (20μV/DIV)
0
246 107135 9
TIME (SEC)
8
17905 G12
Integrated Noise 10Hz to 1kHz
1000
)
RMS
100
10
INTEGRATED NOISE (μV
1
10
100 1000
FREQUENCY (Hz)
NOISE VOLTAGE (μV/√Hz)
2
0
10
17905 G14
100 1k 10k
FREQUENCY (Hz)
IO = 1mA
17905 G13
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18
Page 19
APPLICATIONS INFORMATION
LT1790
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 fi nal value.
All LT1790 voltages perform virtually the same, so the LT1790-2.5 is used as an example.
3V
2V
1V
0V
V
IN
V
OUT
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 V
with the
IN
same capacitors. The test circuit of Figure 3 is used to measure the stability
of various load currents. With R
= 1k, the 1V step produces
L
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.
3V
2V
1V
0V
V
IN
V
OUT
1790 F01
Figure 1. Turn-On Characteristics of LT1790-2.5
V
IN
3V
Figure 3. Response Time Test Circuit
V
GEN
3V
2V
1790 F04
4
C
IN
0.1μF
V
OUT
(AC COUPLED)
LT1790-2.5
1, 2
1790 F02
Figure 2. Output Response to 0.5V Ripple on V
V
GEN
–2V
–3V
C 1μF
1k
L
V
GEN
1V
1790 F03
1790 F05
6
IN
V
OUT
(AC COUPLED)
Figure 4. LT1790-2.5 Sourcing and Sinking 0.5mA
Figure 5. LT1790-2.5 Sourcing 4mA to 5mA
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19
Page 20
LT1790
LT1790-2.5
C
L
1μF
C1
0.1μF
1790 F07
4
1, 2
6
R1
10k
V
OUT
= –2.5V
V
EE
3V
R
L
=
V
EE
– V
OUT
125μA
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 specifi cations 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 confi gured 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
V
GEN
8V
turning on and driving the grounded output. C1 provides stability during load transients. This connection maintains nearly the same accuracy and temperature coeffi cient 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 T
= 30°C,
A
their outputs scanned regularly and measured with an 8.5 digit DVM. Long-term drift curves are shown in the Typical Performance Characteristics section.
6V
V
1790 F06
OUT
(AC COUPLED)
Figure 7. Using the LT1790-2.5 to Build a –2.5V Reference
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4V
2V
0V
Figure 6. LT1790-2.5 Sinking – 4mA to –5mA
20
Page 21
APPLICATIONS INFORMATION
DISTRIBUTION (ppm)
–100 –80 –60 –40 –20 0 20 40 60 80 100
NUMBER OF UNITS
20
25
30
1790 F09
15
10
0
5
50
45
40
–40°C TO 25°C
80°C TO 25°C
35
LT1790
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%).
30
25
20
70°C TO 25°C
15
10
NUMBER OF UNITS
5
0
–60 –50 –40 –30 –20 –10 0
DISTRIBUTION (ppm)
Figure 8. Worst-Case 0°C to 70°C Hysteresis on 79 Units
Figure 9. Worst-Case –40°C to 85°C Hysteresis on 80 Units
10 20
0°C TO 25°C
30 40 50 60
1790 F08
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 V
OUT
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
225
T = 190°C
T = 150°C
150
DEGREES (C)
RAMP TO 150°C
75
0
0246810
Figure 10. Lead-Free Refl ow Profi le
9
8
7
6
5
4
3
NUMBER OF UNITS
2
1
0
01020304050
Figure 11. 1X IR Refl ow Peak Temperature = 250°C,
Delta Output Voltage (ppm)
T
S(MAX)
380s
T
= 217°C
L
= 200°C
120s
MINUTES
PPM
TP = 260°
130s
130s
t
t
40s
RAMP DOWN
P
L
1790 F10
1790 F11
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21
Page 22
LT1790
LT1790-3.3
4V TO 30V
C1
0.1μF
BZX84C18
1μF
V
OUT
R1
1790 F13
LT1790
C1
0.1μF C2 1μF
ON SEMI MMBT5551
V
S
6V TO 160V
V
OUT
1790 F14
R2
4.7k
R1
330k
BZX84C12
LT1790
C2 1μF
BAV99
V
OUT
1790 F15
C1
0.1μF
R1
330k
V
S
6.5V TO 160V
ON SEMI
MMBT5551
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.
3.5
3.0
2.5
2.0
1.5
NUMBER OF UNITS
1.0
Assuming 80μA max supply current for the LT1790, a 25μA load, 120mV max dropout and a 4V to 30V input specifi cation, 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 fi ltering of the Zener noise when the Zener is in its noisy V-I knee.
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.
0.5
0
PPM
2902702502302101901701501301109070
1790 F12
Figure 12. 3X IR Refl ow Peak Temperature = 250°C,
Delta Output Voltage (ppm)
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 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.
22
Figure 13. Extended Supply Range Reference
Figure 14. Extended Supply Range Reference
Figure 15. Extended Supply Range Reference
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Page 23
APPLICATIONS INFORMATION
–
+
LT1790-2.5
LT1782
17909 F16
C2 1μF
NOTE: NOT CURRENT LIMITED
V
OUT
= 2.5V
I
LOAD
= 0mA to 300mA
R3 22Ω 5%
R1 680Ω 5%
V
S
2.8V TO 3.3V NO LOAD
SUPPLY CURRENT
120μA
R2 100k 5%
C1
0.1μF
R4
1k
5%
VISHAY SILICONIX Si3445DV
LT1790
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 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.
Noise
An estimate of the total integrated noise from 10Hz to 1kHz can be made by multiplying the fl at 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
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.
Figure 16. Compact, High Output Current, Low Dropout, Precision 2.5V Supply
1790fb
23
Page 24
LT1790
SIMPLIFIED SCHEMATIC
4
6
1, 2
1790 SS
V
V
IN
OUT
GND
24
1790fb
Page 25
PACKAGE DESCRIPTION
LT1790
S6 Package
6-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1636)
0.62
MAX
3.85 MAX
2.62 REF
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.20 BSC
DATUM ‘A’
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
0.95 REF
1.22 REF
1.4 MIN
0.30 – 0.50 REF
2.80 BSC
0.09 – 0.20 (NOTE 3)
1.50 – 1.75 (NOTE 4)
1.00 MAX
0.95 BSC
0.80 – 0.90
2.90 BSC (NOTE 4)
PIN ONE ID
0.30 – 0.45 6 PLCS (NOTE 3)
0.01 – 0.10
1.90 BSC
S6 TSOT-23 0302 REV B
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.
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25
Page 26
LT1790
LT1790-2.5
1μF
2k
V
Z
= 5.1V
V
CC
= 5V
MPS2907A
V
EE
= –5V
5.1k
1790 TA03
4
1, 2
6
–2.5V 50mA
TYPICAL APPLICATION
RELATED PARTS
–2.5V Negative 50mA Series Reference
No Load Supply Current
I
= 1.6mA
CC
= 440μA
I
EE
PART NUMBER DESCRIPTION COMMENTS
LT1019 Precision Reference Low Noise Bandgap, 0.05%, 5ppm/°C
®
1798 Micropower Low Dropout Reference 0.15% Max, 6.5μA Supply Current
LT C 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
26
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
1790fb
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2000
LT 0609 REV B • PRINTED IN USA
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