LT1461
Micropower Precision
Low Dropout Series
Voltage Reference Family
FeaTures
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DescripTion
The
LT
®
1461
is a family of low dropout micropower band-
gap references that combine very high accuracy and low
drift with low supply current and high output drive. These
series references use advanced curvature compensation
techniques to obtain low temperature coefficient and
trimmed precision thin-film resistors to achieve high
output accuracy. The LT1461 family draws only 35µA
of supply current, making them ideal for low power and
portable applications, however their high 50mA output
drive makes them suitable for higher power requirements,
such as precision regulators.
In low power applications, a dropout voltage of less than
300mV ensures maximum battery life while maintaining
full reference performance. Line regulation is nearly im-
measurable, while the exceedingly good load and ther-
mal regulation will not add significantly to system error
budgets. The shutdown feature can be used to switch full
load currents and can be used for system power down.
Thermal shutdown protects the part from overload condi-
tions. The LT1461 is available in 2.5V, 3V, 3.3V 4.096V
and 5V options.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Trimmed to High Accuracy: 0.04% Max
Low Drift: 3ppm/°C Max
Low Supply Current: 50µA Max
High Output Current: 50mA Min
Low Dropout Voltage: 300mV Max
Excellent Thermal Regulation
Power Shutdown
Thermal Limiting
All Parts Guaranteed Functional from –40°C to 125°C
Voltage Options: 2.5V, 3V, 3.3V, 4.096V and 5V
applicaTions
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A/D and D/A Converters
Precision Regulators
Handheld Instruments
Power Supplies
Typical applicaTion
Basic Connection
(V
OUT
+ 0.3V) ≤ V
IN
≤ 20V
C
IN
1µF
LT1461
C
L
2µF
1461 TA01
LT1461-2.5 Load Regulation, P
DISS
= 200mW
V
OUT
V
OUT
20mA
0mA
V
OUT
LOAD REG
1mV/DIV
10ms/DIV
1461 TA02
1461fb
For more information
www.linear.com/LT1461
1
LT1461
absoluTe MaxiMuM raTings
(Note 1)
pin conFiguraTion
TOP VIEW
DNC* 1
V
IN
2
SHDN
3
GND 4
8
7
6
5
DNC*
DNC*
V
OUT
DNC*
Input Voltage ............................................................20V
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
Specified Temperature Range
Commercial ............................................. 0°C to 70°C
Industrial .............................................–40°C to 85°C
High ................................................... –40°C to 125°C
Lead Temperature (Soldering, 10 sec)................... 300°C
S8 PACKAGE
8-LEAD PLASTIC SO
*DNC: DO NOT CONNECT
T
JMAX
= 150°C,
θ
JA
= 190°C/W
(Note 3)
orDer inForMaTion
LEAD FREE FINISH
LT1461ACS8-2.5#PBF
LT1461ACS8-3#PBF
LT1461ACS8-3.3#PBF
LT1461ACS8-4#PBF
LT1461ACS8-5#PBF
LT1461BCS8-2.5#PBF
LT1461BCS8-3#PBF
LT1461BCS8-3.3#PBF
LT1461BCS8-4#PBF
LT1461BCS8-5#PBF
LT1461CCS8-2.5#PBF
LT1461CCS8-3#PBF
LT1461CCS8-3.3#PBF
LT1461CCS8-4#PBF
LT1461CCS8-5#PBF
LT1461AIS8-2.5#PBF
LT1461AIS8-3#PBF
LT1461AIS8-3.3#PBF
LT1461AIS8-4#PBF
LT1461AIS8-5#PBF
LT1461BIS8-2.5#PBF
LT1461BIS8-3#PBF
LT1461BIS8-3.3#PBF
LT1461BIS8-4#PBF
LT1461BIS8-5#PBF
LT1461CIS8-2.5#PBF
LT1461CIS8-3#PBF
LT1461CIS8-3.3#PBF
TAPE AND REEL
LT1461ACS8-2.5#TRPBF
LT1461ACS8-3#TRPBF
LT1461ACS8-3.3#TRPBF
LT1461ACS8-4#TRPBF
LT1461ACS8-5#TRPBF
LT1461BCS8-2.5#TRPBF
LT1461BCS8-3#TRPBF
LT1461BCS8-3.3#TRPBF
LT1461BCS8-4#TRPBF
LT1461BCS8-5#TRPBF
LT1461CCS8-2.5#TRPBF
LT1461CCS8-3#TRPBF
LT1461CCS8-3.3#TRPBF
LT1461CCS8-4#TRPBF
LT1461CCS8-5#TRPBF
LT1461AIS8-2.5#TRPBF
LT1461AIS8-3#TRPBF
LT1461AIS8-3.3#TRPBF
LT1461AIS8-4#TRPBF
LT1461AIS8-5#TRPBF
LT1461BIS8-2.5#TRPBF
LT1461BIS8-3#TRPBF
LT1461BIS8-3.3#TRPBF
LT1461BIS8-4#TRPBF
LT1461BIS8-5#TRPBF
LT1461CIS8-2.5#TRPBF
LT1461CIS8-3#TRPBF
LT1461CIS8-3.3#TRPBF
PART MARKING
461A25
1461A3
461A33
1461A4
1461A5
461B25
1461B3
461B33
1461B4
1461B5
461C25
1461C3
461C33
1461C4
1461C5
61AI25
461AI3
61AI33
461AI4
461AI5
61BI25
461BI3
61BI33
461BI4
461BI5
61CI25
461CI3
61CI33
PACKAGE DESCRIPTION
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
SPECIFIED TEMPERATURE RANGE
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
1461fb
2
For more information
www.linear.com/LT1461
LT1461
orDer inForMaTion
LEAD FREE FINISH
LT1461CIS8-4#PBF
LT1461CIS8-5#PBF
LT1461DHS8-2.5#PBF
LT1461DHS8-3#PBF
LT1461DHS8-3.3#PBF
LT1461DHS8-4#PBF
LT1461DHS8-5#PBF
TAPE AND REEL
LT1461CIS8-4#TRPBF
LT1461CIS8-5#TRPBF
LT1461DHS8-2.5#TRPBF
LT1461DHS8-3#TRPBF
LT1461DHS8-3.3#TRPBF
LT1461DHS8-4#TRPBF
LT1461DHS8-5#TRPBF
PART MARKING
461CI4
461CI5
61DH25
461DH3
61DH33
461DH4
461DH5
PACKAGE DESCRIPTION
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
8-LEAD PLASTIC SO
SPECIFIED TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on nonstandard lead based finish parts.
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/
available opTions
INITIAL
ACCURACY
0.04% Max
0.04% Max
0.06% Max
0.06% Max
0.08% Max
0.08% Max
0.15% Max
TEMPERATURE
COEFFICIENT
3ppm/°C Max
3ppm/°C Max
7ppm/°C Max
7ppm/°C Max
12ppm/°C Max
12ppm/°C Max
20ppm/°C Max
TEMPERATURE
RANGE
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
–40°C to 125°C
OUTPUT VOLTAGE
2.5V
LT1461ACS8-2.5
LT1461AIS8-2.5
LT1461BCS8-2.5
LT1461BIS8-2.5
LT1461CCS8-2.5
LT1461CIS8-2.5
LT1461DHS8-2.5
3.0V
LT1461ACS8-3
LT1461AIS8-3
LT1461BCS8-3
LT1461BIS8-3
LT1461CCS8-3
LT1461CIS8-3
LT1461DHS8-3
3.3V
LT1461ACS8-3.3
LT1461AIS8-3.3
LT1461BCS8-3.3
LT1461BIS8-3.3
LT1461CCS8-3.3
LT1461CIS8-3.3
LT1461DHS8-3.3
4.096V
LT1461ACS8-4
LT1461AIS8-4
LT1461BCS8-4
LT1461BIS8-4
LT1461CCS8-4
LT1461CIS8-4
LT1461DHS8-4
5.0V
LT1461ACS8-5
LT1461AIS8-5
LT1461BCS8-5
LT1461BIS8-5
LT1461CCS8-5
LT1461CIS8-5
LT1461DHS8-5
The
l
denotes the specifications which apply over the specified
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
– V
OUT
= 0.5V, Pin 3 = 2.4V, C
L
= 2µF, unless otherwise specified.
PARAMETER
Output Voltage (Note 4)
CONDITIONS
LT1461ACS8/LT1461AIS8
LT1461BCS8/LT1461BIS8
LT1461CCS8/LT1461CIS8
LT1461DHS8
LT1461ACS8/LT1461AIS8
LT1461BCS8/LT1461BIS8
LT1461CCS8/LT1461CIS8
LT1461DHS8
(V
OUT
+ 0.5V) ≤ V
IN
≤ 20V
l
l
l
l
l
elecTrical characTerisTics
MIN
–0.04
–0.06
–0.08
–0.15
TYP
MAX
0.04
0.06
0.08
0.15
UNITS
%
%
%
%
ppm/°C
ppm/°C
ppm/°C
ppm/°C
ppm/V
ppm/V
ppm/V
ppm/mA
ppm/mA
ppm/mA
Output Voltage Temperature Coefficient (Note 5)
1
3
5
7
2
3
7
12
20
8
12
50
30
40
50
Line Regulation
LT1461DHS8
Load Regulation Sourcing (Note 6)
V
IN
= V
OUT
+ 2.5V
0 ≤ I
OUT
≤ 50mA
l
15
12
l
LT1461DHS8, 0 ≤ I
OUT
≤ 10mA
l
1461fb
For more information
www.linear.com/LT1461
3
LT1461
The
l
denotes the specifications which apply over the specified
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
– V
OUT
= 0.5V, Pin 3 = 2.4V, C
L
= 2µF, unless otherwise specified.
PARAMETER
Dropout Voltage
CONDITIONS
V
IN
– V
OUT
, V
OUT
Error = 0.1%
I
OUT
= 0mA
I
OUT
= 1mA
I
OUT
= 10mA
I
OUT
= 50mA, I and C Grades Only
Short V
OUT
to GND
Logic High Input Voltage
Logic High Input Current, Pin 3 = 2.4V
Logic Low Input Voltage
Logic Low Input Current, Pin 3 = 0.8V
Supply Current
Shutdown Current
Output Voltage Noise (Note 7)
Long-Term Drift of Output Voltage, SO-8 Package (Note 8)
Thermal Hysteresis (Note 9)
No Load
l
l
l
l
l
elecTrical characTerisTics
MIN
TYP
0.06
0.13
0.20
1.50
100
MAX
UNITS
V
V
V
V
mA
V
µA
V
µA
µA
µA
µA
µA
ppm
P-P
ppm
RMS
ppm/√kHr
ppm
ppm
ppm
l
l
l
0.3
0.4
2.0
Output Current
Shutdown Pin
2.4
2
0.5
35
25
15
0.8
4
50
70
35
55
R
L
= 1k
l
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
See Applications Information
∆T = 0°C to 70°C
∆T = –40°C to 85°C
∆T = –40°C to 125°C
8
9.6
60
40
75
120
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 LT1461 is guaranteed functional over the operating
temperature range of –40°C to 125°C.
Note 3:
Output may shift due to thermal hysteresis. Thermal hysteresis
affects parts during storage as well as operation.
Note 4:
ESD (Electrostatic Discharge) sensitive device. Extensive use of
ESD protection devices are used internal to the LT1461, however, high
electrostatic discharge can damage or degrade the device. Use proper ESD
handling precautions.
Note 5:
Temperature coefficient is calculated from the minimum and
maximum output voltage measured at T
MIN
, Room and T
MAX
as follows:
TC = (V
OMAX
– V
OMIN
)/(T
MAX
– T
MIN
)
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:
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. RMS noise is measured with a single pole highpass
filter at 10Hz and a 2-pole lowpass filter at 1kHz. The resulting output is
full-wave rectified and then integrated for a fixed period, making the final
reading an average as opposed to RMS. A correction factor of 1.1 is used
to convert from average to RMS and a second correction of 0.88 is used to
correct for the nonideal bandpass of the filters.
Note 8:
Long-term drift typically has a logarithmic characteristic and
therefore, changes after 1000 hours tend to be much smaller than before
that time. Total drift in the second thousand hours is normally less than
one third that of the first thousand hours with a continuing trend toward
reduced drift with time. Long-term drift will also be affected by differential
stresses between the IC and the board material created during board
assembly. See the Applications Information section.
Note 9:
Hysteresis in output voltage is created by package stress
that depends 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 hot or cold before successive measurements. Hysteresis is roughly
proportional to the square of the temperature change. Hysteresis is not
normally a problem for operational temperature excursions where the
instrument might be stored at high or low temperature. See Applications
Information section.
1461fb
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For more information
www.linear.com/LT1461
LT1461
Characteristic curves are similar for most LT1461s.
Curves from the LT1461-2.5 and the LT1461-5 represent the extremes of the voltage options. Characteristic curves for other output
voltages fall between these curves and can be estimated based on their output.
2.5V Reference Voltage
vs Temperature
2.5020
2.5015
REFERENCE VOLTAGE (V)
2.5010
2.5005
2.5000
2.4995
2.4990
2.4985
2.4980
– 60 – 40 – 20
0 20 40 60 80 100 120
TEMPERATURE (°C)
1461 G01
Typical perForMance characTerisTics
2.5V Load Regulation
1600
OUTPUT VOLTAGE CHANGE (ppm)
V
IN
= 7.5V
LINE REGULATION (ppm/V)
0
–1
1200
125°C
25°C
–2
–3
–4
–5
–6
–7
2.5V Line Regulation
vs Temperature
TEMPCO –60°C TO 120°C
3 TYPICAL PARTS
800
400
– 55°C
0
0.1
1
10
OUTPUT CURRENT (mA)
100
1461 G02
–8
–40 – 20
SUPPLY ∆ = 15V
5V – 20V
0
60 80
TEMPERATURE (°C)
20
40
100 120
1461 G03
2.5V Minimum Input/Output
Voltage Differential vs Load Current
10
1000
2.5V Supply Current
vs Input Voltage
100
90
RIPPLE REJECTION RATIO (dB)
2.5V Ripple Rejection Ratio
vs Frequency
INPUT/OUTPUT VOLTAGE (V)
80
70
60
50
40
30
20
10
1
125°C
25°C
– 55°C
0.1
0.1
1
10
OUTPUT CURRENT (mA)
100
1461 G04
SUPPLY CURRENT (µA)
100
125°C
– 55°C
25°C
10
0
5
10
15
20
INPUT VOLTAGE (V)
25
1461 G05
0
0.01
0.1
1
10
FREQUENCY (kHz)
100
1000
1641 G06
2.5V Output Impedance
vs Frequency
1000
C
OUT
= 2µF
OUTPUT IMPEDANCE ( )
C
OUT
= 1µF
VOLTAGE (V)
20
10
2.5V Turn-On Time
V
IN
20
10
VOLTAGE (V)
0
2.5V Turn-On Time
V
IN
100
0
10
2
1
0
V
OUT
C
IN
= 1µF
C
L
= 2µF
R
L
=
∞
TIME (100µs/DIV)
1461 G08
2
1
0
V
OUT
C
IN
= 1µF
C
L
= 2µF
R
L
= 50
TIME (100µs/DIV)
1461 G09
1
0.01
0.1
1
FREQUENCY (kHz)
10
1461 G07
1461fb
For more information
www.linear.com/LT1461
5
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