FeaTures
n
LT1027LS8
Precision, Low Noise,
High Stability Hermetic
Voltage Reference
DescripTion
The
LT
®
1027LS8
is a precision reference that combines
low drift and noise with excellent long-term stability and
high output accuracy. The reference output will source up
to 15mA and sink up to 10mA, and remain constant with
input voltage variations.
The hermetic package provides outstanding humidity and
thermal hysteresis performance. The LT1027LS8 is only
5mm
×
5mm
×
1.5mm, offering an alternative to large
through-hole metal can voltage references, such as the
industry standard LT1021. The LT1027LS8 offers similar
performance to the LT1027, with additional stability from
the hermetic package.
LT1027LS8 is based on a buried Zener diode structure,
which enables temperature and time stability, and ex-
tremely low noise performance of < 1ppm peak-to-peak.
The LT1027LS8 operates on a supply voltage from 8V up
to 40V. The subsurface Zener exhibits better time stability
than even the best bandgap reference, and the hermetic
package maintains that stability over a wide range of
environmental conditions.
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.
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Hermetic 5mm
×
5mm LCC Leadless Chip Carrier
Package:
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Insensitive to Humidity
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Thermal Hysteresis: 8ppm (0°C to 70°C)
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Thermal Hysteresis: 12ppm (–40°C to 85°C)
Low Drift: 5ppm/°C Max
High Accuracy: ±0.10% Max
Low Noise: <1ppm Peak-to-Peak (0.1Hz to 10Hz)
Low Long Term Drift
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12ppm at 1000Hr
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18ppm at 3000Hr
Sinks 10mA, Sources 15mA
Wide Supply Range to 40V
8-Pin (5mm
×
5mm) LS8 Package
applicaTions
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Instrumentation and Test Equipment
High Resolution Data Acquisition Systems
A/D and D/A Converters
Precision Regulators
Precision Scales
Digital Voltmeters
Typical applicaTion
Supplying V
REF
and V
CC
to the LTC1290 12-Bit ADC
5.010
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
COM
REF
+
V
CC
S
CLK
A
CLK
D
OUT
D
IN
CS
Output Voltage Temperature Drift
ANALOG
INPUTS
8V TO 40V
OUTPUT VOLTAGE (V)
TO µC
5.005
5.000
LTC1290
V
IN
4.995
+
V
OUT
2.2µF
LT1027LS8
V
TRIM
10k
+
REF
–
22µF
AGND
V
–
DGND
4.990
–40 –25
GND
0
25
50
TEMPERATURE (°C)
75 85
1027LS8 TA01b
1027LS8 TA01a
1027ls8f
For more information
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1
LT1027LS8
absoluTe MaxiMuM raTings
(Note 1)
pin conFiguraTion
TOP VIEW
V
IN
NR
V
OUT
V
TRIM
1
2
3
4
8
7
6
5
NC*
NC*
NC*
Input Voltage.............................................................40V
Input/Output Voltage Differential ..............................35V
Output to Ground Voltage ...........................................7V
V
TRIM
to Ground Voltage
Positive ...................................................................5V
Negative .............................................................–0.3V
Output Short-Circuit Duration
V
IN
> 20V ..........................................................10 sec
V
IN
≤ 20V ..................................................... Indefinite
Operating Temperature Range
LT1027C................................................... 0°C to 70°C
LT1027I ................................................– 40°C to 85°C
Storage Temperature Range .................. –65°C to 150°C
GND
LS8 PACKAGE
8-PIN LEADLESS CHIP CARRIER (5mm
×
5mm)
*CONNECTED INTERNALLY.
D0 NOT CONNECT EXTERNAL
CIRCUITRY TO THESE PINS
**SEE APPLICATIONS
INFORMATION SECTION
T
JMAX
= 125°C,
θ
JA
= 120°C/W
PACKAGE LID IS GND
orDer inForMaTion
LEAD FREE FINISH
LT1027DCLS8-5#PBF
LT1027DILS8-5#PBF
PART MARKING
10275
10275
(http://www.linear.com/product/LT1027LS8#orderinfo)
PACKAGE DESCRIPTION
8-Lead Ceramic LCC 5mm × 5mm
8-Lead Ceramic LCC 5mm × 5mm
SPECIFIED TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
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/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
2
1027ls8f
For more information
www.linear.com/LT1027LS8
LT1027LS8
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 10V, I
LOAD
= 0A unless otherwise specified.
SYMBOL PARAMETER
V
OUT
TCV
OUT
Output Voltage (Note 2)
Output Voltage Temperature Coefficient (Note 3)
Line Regulation (Note 4)
8V ≤ V
IN
≤ 10V
l
l
elecTrical characTerisTics
CONDITIONS
MIN
4.995
TYP
5.000
2
6
3
MAX
5.005
5
12
25
6
8
12
15
15
120
160
3.1
3.5
UNITS
V
ppm/°C
ppm/V
ppm/V
ppm/V
ppm/V
ppm/mA
ppm/mA
ppm/mA
ppm/mA
ppm/mA
mA
mA
mV
µV
P-P
10V ≤ V
IN
≤ 40V
l
Load Regulation (Notes 4, 6)
Sourcing Current
0 ≤ I
OUT
≤ 15mA, 0°C to 85°C
0 ≤ I
OUT
≤ 5mA, –40°C
Sinking Current 0 ≤ I
OUT
≤ 10mA
0°C to 85°C
–40°C
l
–8
–10
–10
8
l
30
2.2
Supply Current
l
V
TRIM
Adjust Range
e
n
Output Noise (Note 5)
Long-Term Stability of Output Voltage (Note 7)
Temperature Hysteresis of Output (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
∆t = First 1000Hrs
∆t = First 3000Hrs
∆T = ±25°C
∆T = 0°C to 70°C
∆T = –40°C to 85°C
l
±30
±50
3
2.0
12
18
6
8
12
6.0
µV
RMS
ppm
ppm
ppm
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 2:
Output voltage is measured immediately after turn-on. Changes
due to chip warm-up are typically less than 0.005%.
Note 3:
Temperature coefficient is measured by dividing the change in
output voltage over the temperature range by the change in temperature.
Note 4:
Line and load regulation are measured on a pulse basis. Output
changes due to die temperature change must be taken into account
separately.
Note 5:
RMS noise is measured with an 8-pole bandpass filter with a
center frequency of 30Hz and a Q of 1.5. The filter output is then rectified
and integrated for a fixed time period, resulting in an average, as opposed
to RMS voltage. A correction factor is used to convert average to RMS.
This value is then used to obtain RMS noise voltage in the 10Hz to 1000Hz
frequency band. This test also screens for low frequency “popcorn” noise
within the bandwidth of the filter.
Note 6:
Devices typically exhibit a slight negative DC output impedance of
–0.015Ω. This compensates for PC trace resistance, improving regulation
at the load.
Note 7:
Long-term stability 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. Significant improvement in long-term drift can be
realized by preconditioning the IC with a 100-200 hour, 125°C burn in.
Long term stability will also be affected by differential stresses between
the IC and the board material created during board assembly. Temperature
cycling and baking of completed boards is often used to reduce these
stresses in critical applications.
Note 8:
Hysteresis in 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 high or low temperature before successive measurements.
Hysteresis is roughly proportional to the square of temperature change.
Hysteresis is not normally a problem for operational temperature
excursions, but can be significant in critical narrow temperature range
applications where the instrument might be stored at high or low
temperatures. Hysteresis measurements are preconditioned by one
temperature cycle.
1027ls8f
For more information
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3
LT1027LS8
Typical perForMance characTerisTics
Ripple Rejection
100
120
110
REJECTION (dB)
100
90
80
70
60
50
10
100
1k
FREQUENCY (Hz)
10k
1027LS8 G01
Output Impedance vs Frequency
100
∆I = 3mA AC
I
SOURCE
= 5mA
OUTPUT VOLTAGE (V)
5.010
Output Voltage Temperature Drift
V
IN
= 10V
OUTPUT IMPEDANCE (Ω)
10
5.005
1
5.000
0.1
0.01
10
100
1k
10k
FREQUENCY (Hz)
100k
1M
4.995
4.990
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
1027LS8 G03
1027LS8 G02
Start-Up and Turn-Off (No Load)
Start-Up and Turn-Off
2.5
Quiescent Current
V
OUT
1V/DIV
V
IN
10V
10V
V
IN
R
L
= 1k, C
L
= 4.7µF
1µs/DIV
1027LS8 G04
SUPPLY CURRENT (mA)
V
OUT
1V/DIV
2.0
1.5
500µs/DIV
1027LS8 G05
1.0
0.5
0
0
5
10
15 20
25 30
INPUT VOLTAGE (V)
35
40
1027LS8 G06
Load Regulation
800
CHANGE IN OUTPUT VOLTAGE (µV)
SHORT–CIRCUIT CURRENT (mA)
400
0
–400
–800
–1200
–1600
–10 –8 –6 –4 –2 0 2 4 6 8 10 12 14 16
Sink Source
I
OUT
(mA)
1027LS8 G07
Output Short-Circuit Current
vs Temperature
25
CHANGE IN OUTPUT VOLTAGE (µV)
20
15
10
5
0
–5
–10
–15
–20
–25
–50
–30
–10 10
30
50
TEMPERATURE (°C)
70
90
SINKING
SOURCING
500
400
300
200
100
0
–100
–200
–300
Line Regulation
V
IN
= 10V
V
OUT
= 5V
–400
–500
8
12
16
20 24
28 32
INPUT VOLTAGE (V)
36
40
1027LS8 G08
1027LS8 G09
4
1027ls8f
For more information
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LT1027LS8
Typical perForMance characTerisTics
Output Noise Voltage Density
200
OUTPUT NOISE DENSITY (nV/√Hz)
180
160
140
120
100
80
60
40
20
0
10
100
1k
FREQUENCY (Hz)
10k
1027LS8 G10
Output Settling Time (Sourcing)
V
OUT
400µV/DIV
AC-COUPLED
10mA
LOAD STEP
C
NR
= 0
C
NR
= 1µF
2µs/DIV
1027LS8 G11
Output Settling Time (Sinking)
0.1Hz to 10Hz Output Noise
Filtering = 1 Zero at 0.1Hz
2 Poles at 10Hz
V
OUT
400µV/DIV
AC-COUPLED
–10mA
LOAD STEP
2µs/DIV
1027LS8 G12
5µV/DIV
1sec/DIV
1027LS8 G13
1027ls8f
For more information
www.linear.com/LT1027LS8
5
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