1
LT1236
Precision Reference
U
A
O
PPLICATITYPICAL
D
U
ESCRIPTIO
The LT
®
1236 is a precision reference that combines ultra-
low drift and noise with excellent long-term stability and
high output accuracy. The reference output will both
source and sink up to 10mA and is almost totally immune
to input voltage variations. Two voltages are available: 5V
and 10V. The 10V version can be used as a shunt regulator
(two-terminal zener) with the same precision characteris-
tics as the three-terminal connection. Special care has
been taken to minimize thermal regulation effects and
temperature induced hysteresis.
The LT1236 combines both superior accuracy and tem-
perature coefficient specifications without the use of high
power, on-chip heaters. The LT1236 references are based
on a buried zener diode structure which eliminates noise
and stability problems with surface breakdown devices.
Further, a subsurface zener exhibits better temperature
drift and time stability than even the best band-gap
references.
S
FEATURE
■
Ultra-Low Drift: 5ppm/°C Max
■
Trimmed to High Accuracy: 0.05% Max
■
Industrial Temperature Range SO Package
■
Operates in Series or Shunt Mode
■
Pin Compatible with AD586, AD587
■
Output Sinks and Sources in Series Mode
■
Very Low Noise < 1ppm
P-P
(0.1Hz to 10Hz)
■
100% Noise Tested
■
> 100dB Ripple Rejection
■
Minimum Input/Output Differential of 1V
, LTC and LT are registered trademarks of Linear Technology Corporation.
Typical Distribution of Temperature Drift
Basic Positive and Negative Connections
LT1236
OUT
IN
GND
LT1236-10
OUT
IN
GND
V
OUT
–V
OUT
V
IN
NC
R1 = V
OUT
– (V
–
)
I
LOAD
+ 1.5mA
–15V
(V
–
)
R1
LT1236 TA01
OUTPUT DRIFT (ppm/°C)
–3
0
UNITS (%)
4
8
12
16
24
22
–2 –1 0 1
LT1236 TA02
23
20
18
14
10
6
2
DISTRIBUTION
OF THREE RUNS
U
S
A
O
PPLICATI
■
A/D and D/A Converters
■
Precision Regulators
■
Precision Scales
■
Inertial Navigation Systems
■
Digital Voltmeters
2
LT1236
1
2
3
4
8
7
6
5
TOP VIEW
NC*
V
IN
NC*
GND
NC*
NC*
V
0UT
TRIM**
S8 PACKAGE
8-LEAD PLASTIC SO
CONNECTED INTERNALLY.
D0 NOT CONNECT EXTERNAL
CIRCUITRY TO THESE PINS
SEE APPLICATIONS
INFORMATION SECTION
*
**
A
U
G
W
A
W
U
W
ARBSOLUTEXI T
I
S
Input Voltage .......................................................... 40V
Input/Output Voltage Differential ............................ 35V
Output-to-Ground Voltage (Shunt Mode Current Limit)
LT1236-5............................................................. 10V
LT1236-10........................................................... 16V
Trim Pin-to-Ground Voltage
Positive................................................ Equal to V
OUT
Negative ........................................................... – 20V
Output Short-Circuit Duration
V
IN
= 35V......................................................... 10 sec
V
IN
≤ 20V ................................................... Indefinite
Operating Temperature Range
LT1236AC, BC, CC.................................. 0°C to 70°C
LT1236AI, BI, CI ................................ –40°C to 85°C
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................ 300°C
WU
U
PACKAGE/ORDER I FOR ATIO
Consult factory for Military grade parts.
ELECTRICAL C CHARA TERISTICS
VIN = 10V, IOUT = 0, TA = 25°C, unless otherwise noted.
LT1236-5
PARAMETER CONDITIONS MIN TYP MAX UNITS
Output Voltage (Note 1) LT1236A-5 4.9975 5.000 5.0025 V
LT1236B-5/LT1236C-5 4.9950 5.000 5.0050 V
Output Voltage Temperature Coefficient (Note 2) T
MIN
≤ T
J
≤ T
MAX
LT1236A-5 2 5 ppm/°C
LT1236B-5 5 10 ppm/°C
LT1236C-5 10 15 ppm/°C
Line Regulation (Note 3) 7.2V ≤ V
IN
≤ 10V 4 12 ppm/V
●20 ppm/V
10V ≤ V
IN
≤ 40V 2 6 ppm/V
●10 ppm/V
Load Regulation (Sourcing Current) 0 ≤ I
OUT
≤ 10mA 10 20 ppm/mA
(Note 3) ●35 ppm/mA
LT1236AIS8-5
LT1236BIS8-5
LT1236CIS8-5
LT1236AIS8-10
LT1236BIS8-10
LT1236CIS8-10
ORDER PART
NUMBER
S8 PART MARKING
LT1236ACS8-5
LT1236BCS8-5
LT1236CCS8-5
LT1236ACS8-10
LT1236BCS8-10
LT1236CCS8-10
236AC5
236BC5
236CC5
236AC1
236BC1
236CC1
236AI5
236BI5
236CI5
236AI1
236BI1
236CI1
T
JMAX
= 125°C, θ
JA
= 190°C/WT
JMAX
= 125°C, θ
JA
= 130°C/W
ORDER PART
NUMBER
LT1236ACN8-5
LT1236BCN8-5
LT1236CCN8-5
LT1236ACN8-10
LT1236BCN8-10
LT1236CCN8-10
LT1236AIN8-5
LT1236BIN8-5
LT1236CIN8-5
LT1236AIN8-10
LT1236BIN8-10
LT1236CIN8-10
1
2
3
4
8
7
6
5
TOP VIEW
NC*
V
IN
NC*
GND
NC*
NC*
V
0UT
TRIM**
N8 PACKAGE
8-LEAD PDIP
CONNECTED INTERNALLY.
D0 NOT CONNECT EXTERNAL
CIRCUITRY TO THESE PINS
SEE APPLICATIONS
INFORMATION SECTION
*
**
3
LT1236
ELECTRICAL C CHARA TERISTICS
VIN = 10V, IOUT = 0, TA = 25°C, unless otherwise noted.
LT1236-10
PARAMETER CONDITIONS MIN TYP MAX UNITS
Output Voltage (Note 1) LT1236A-10 9.995 10.000 10.005 V
LT1236B-10/LT1236C-10 9.990 10.000 10.010 V
Output Voltage Temperature Coefficient (Note 2) T
MIN
≤ T
J
≤ T
MAX
LT1236A-10 2 5 ppm/°C
LT1236B-10 5 10 ppm/°C
LT1236C-10 10 15 ppm/°C
Line Regulation (Note 3) 11.5V ≤ V
IN
≤ 14.5V 1.0 4 ppm/V
●6 ppm/V
14.5V ≤ V
IN
≤ 40V 0.5 2 ppm/V
●4 ppm/V
Load Regulation (Sourcing Current) 0 ≤ I
OUT
≤ 10mA 12 25 ppm/mA
(Note 3) ●40 ppm/mA
Load Regulation (Shunt Mode) 1.7mA ≤ I
SHUNT
≤ 10mA 50 100 ppm/mA
(Notes 3, 4) ●150 ppm/mA
Series Mode Supply Current 1.2 1.7 mA
●2.0 mA
Shunt Mode Minimum Current V
IN
is Open 1.1 1.5 mA
●1.7 mA
Output Voltage Noise (Note 5) 0.1Hz ≤ f ≤ 10Hz 6.0 µV
P-P
10Hz ≤ f ≤ 1kHz 3.5 6 µV
RMS
Long-Term Stablility of Output Voltage (Note 6) ∆t = 1000Hrs Non-Cumulative 30 ppm
Temperature Hysteresis of Output (Note 7) ∆T = ±25°C 5 ppm
VIN = 15V, IOUT = 0, TA= 25°C, unless otherwise noted.
Note 5: RMS noise is measured with a 2-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. Correction factors are used to convert from average to
RMS, and 0.88 is used to correct for the non-ideal bandbass of the filters.
Peak-to-peak noise is measured with a single 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. Test time is 10 seconds.
Note 6: 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
The ● denotes specifications which apply over the specified temperature
range.
Note 1: Output voltage is measured immediately after turn-on. Changes
due to chip warm-up are typically less than 0.005%.
Note 2: Temperature coefficient is measured by dividing the change in
output voltage over the temperature range by the change in temperature.
Incremental slope is also measured at 25°C.
Note 3: Line and load regulation are measured on a pulse basis. Output
changes due to die temperature change must be taken into account
separately.
Note 4: Shunt mode regulation is measured with the input open. With the
input connected, shunt mode current can be reduced to 0mA. Load
regulation will remain the same.
LT1236-5
PARAMETER CONDITIONS MIN TYP MAX UNITS
Load Regulation (Sinking Current) 0 ≤ I
OUT
≤ 10mA 60 100 ppm/mA
(Note 3) ●150 ppm/mA
Supply Current 0.8 1.2 mA
●1.5 mA
Output Voltage Noise 0.1Hz ≤ f ≤ 10Hz 3.0 µV
P-P
(Note 5) 10Hz ≤ f ≤ 1kHz 2.2 3.5 µV
RMS
Long-Term Stability of Output Voltage (Note 6) ∆t = 1000Hrs Non-Cumulative 20 ppm
Temperature Hysteresis of Output (Note 7) ∆T = ±25°C 10 ppm
