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LT1236BIN8-10 [Linear]

Precision Reference; 精密基准
LT1236BIN8-10
型号： LT1236BIN8-10
厂家： Linear    Linear
描述：

Precision Reference
精密基准
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中文：  中文翻译
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LT1236  
Precision Reference  
U
DESCRIPTIO  
EATURE  
S
F
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  
and10V. The10Vversioncanbeusedasashuntregulator  
(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.  
■
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■
■
■
■
■
■
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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  
The LT1236 combines both superior accuracy and tem-  
peraturecoefficientspecificationswithouttheuseofhigh  
power,on-chipheaters.TheLT1236referencesarebased  
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.  
O U  
PPLICATI  
S
A
■
■
■
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A/D and D/A Converters  
Precision Regulators  
Precision Scales  
Inertial Navigation Systems  
Digital Voltmeters  
, LTC and LT are registered trademarks of Linear Technology Corporation.  
U
O
TYPICAL APPLICATI  
Typical Distribution of Temperature Drift  
Basic Positive and Negative Connections  
24  
DISTRIBUTION  
OF THREE RUNS  
22  
LT1236  
LT1236-10  
IN  
OUT  
20  
18  
16  
14  
12  
10  
8
V
IN  
IN  
V
OUT  
OUT  
NC  
GND  
GND  
–V  
OUT  
–
V
OUT  
– (V )  
+ 1.5mA  
R1 =  
R1  
–15V  
I
LOAD  
6
–
(V  
)
4
LT1236 TA01  
2
0
–3  
–1  
0
1
2
3
–2  
OUTPUT DRIFT (ppm/°C)  
LT1236 TA02  
1
LT1236  
W W W  
U
ABSOLUTE AXI U RATI GS  
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  
Output Short-Circuit Duration  
VIN = 35V......................................................... 10 sec  
VIN ≤ 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  
Positive................................................ Equal to VOUT  
Negative ........................................................... – 20V  
W
U
/O  
PACKAGE RDER I FOR ATIO  
ORDER PART  
NUMBER  
ORDER PART  
NUMBER  
TOP VIEW  
TOP VIEW  
LT1236ACN8-5  
LT1236ACS8-5 LT1236AIS8-5  
NC*  
1
2
3
4
NC*  
NC*  
8
7
6
5
LT1236BCN8-5  
LT1236CCN8-5  
LT1236ACN8-10  
LT1236BCN8-10  
LT1236CCN8-10  
LT1236AIN8-5  
LT1236BIN8-5  
LT1236CIN8-5  
LT1236AIN8-10  
LT1236BIN8-10  
LT1236CIN8-10  
NC*  
1
2
3
4
NC*  
NC*  
LT1236BIS8-5  
LT1236CIS8-5  
LT1236AIS8-10  
8
7
6
5
LT1236BCS8-5  
LT1236CCS8-5  
LT1236ACS8-10  
V
IN  
V
IN  
NC*  
GND  
V
NC*  
GND  
V
0UT  
0UT  
LT1236BCS8-10 LT1236BIS8-10  
LT1236CCS8-10 LT1236CIS8-10  
TRIM**  
TRIM**  
N8 PACKAGE  
8-LEAD PDIP  
S8 PACKAGE  
8-LEAD PLASTIC SO  
*CONNECTED INTERNALLY.  
D0 NOT CONNECT EXTERNAL  
CIRCUITRY TO THESE PINS  
S8 PART MARKING  
*CONNECTED INTERNALLY.  
D0 NOT CONNECT EXTERNAL  
CIRCUITRY TO THESE PINS  
236AC5  
236BC5  
236CC5  
236AC1  
236BC1  
236CC1  
236AI5  
236BI5  
236CI5  
236AI1  
236BI1  
236CI1  
**SEE APPLICATIONS  
INFORMATION SECTION  
**SEE APPLICATIONS  
INFORMATION SECTION  
TJMAX = 125°C, θJA = 130°C/W  
TJMAX = 125°C, θJA = 190°C/W  
Consult factory for Military grade parts.  
ELECTRICAL CHARACTERISTICS VIN = 10V, IOUT = 0, TA = 25°C, unless otherwise noted.  
LT1236-5  
TYP  
PARAMETER  
CONDITIONS  
MIN  
MAX  
UNITS  
Output Voltage (Note 1)  
LT1236A-5  
LT1236B-5/LT1236C-5  
4.9975  
4.9950  
5.000  
5.000  
5.0025  
5.0050  
V
V
Output Voltage Temperature Coefficient (Note 2)  
Line Regulation (Note 3)  
T
≤ T ≤ T  
MIN J MAX  
LT1236A-5  
LT1236B-5  
LT1236C-5  
2
5
10  
5
10  
15  
ppm/°C  
ppm/°C  
ppm/°C  
7.2V ≤ V ≤ 10V  
4
12  
20  
6
ppm/V  
ppm/V  
ppm/V  
ppm/V  
IN  
●
●
10V ≤ V ≤ 40V  
2
IN  
10  
Load Regulation (Sourcing Current)  
(Note 3)  
0 ≤ I  
≤ 10mA  
10  
20  
35  
ppm/mA  
ppm/mA  
OUT  
●
2
LT1236  
ELECTRICAL CHARACTERISTICS VIN = 10V, IOUT = 0, TA = 25°C, unless otherwise noted.  
LT1236-5  
TYP  
PARAMETER  
CONDITIONS  
0 ≤ I ≤ 10mA  
MIN  
MAX  
UNITS  
Load Regulation (Sinking Current)  
(Note 3)  
60  
100  
150  
ppm/mA  
ppm/mA  
OUT  
●
●
Supply Current  
0.8  
1.2  
1.5  
mA  
mA  
Output Voltage Noise  
(Note 5)  
0.1Hz ≤ f ≤ 10Hz  
10Hz ≤ f ≤ 1kHz  
3.0  
2.2  
µV  
P-P  
3.5  
µV  
RMS  
Long-Term Stability of Output Voltage (Note 6)  
Temperature Hysteresis of Output (Note 7)  
∆t = 1000Hrs Non-Cumulative  
∆T = ±25°C  
20  
10  
ppm  
ppm  
VIN = 15V, IOUT = 0, TA= 25°C, unless otherwise noted.  
LT1236-10  
TYP  
PARAMETER  
CONDITIONS  
MIN  
MAX  
UNITS  
Output Voltage (Note 1)  
LT1236A-10  
LT1236B-10/LT1236C-10  
9.995  
9.990  
10.000 10.005  
10.000 10.010  
V
V
Output Voltage Temperature Coefficient (Note 2)  
Line Regulation (Note 3)  
T
≤ T ≤ T  
MIN J MAX  
LT1236A-10  
LT1236B-10  
LT1236C-10  
2
5
10  
5
10  
15  
ppm/°C  
ppm/°C  
ppm/°C  
11.5V ≤ V ≤ 14.5V  
1.0  
4
6
2
4
ppm/V  
ppm/V  
ppm/V  
ppm/V  
IN  
●
●
14.5V ≤ V ≤ 40V  
0.5  
IN  
Load Regulation (Sourcing Current)  
(Note 3)  
0 ≤ I  
≤ 10mA  
12  
50  
25  
40  
ppm/mA  
ppm/mA  
OUT  
●
●
●
●
Load Regulation (Shunt Mode)  
(Notes 3, 4)  
1.7mA ≤ I  
≤ 10mA  
100  
150  
ppm/mA  
ppm/mA  
SHUNT  
Series Mode Supply Current  
Shunt Mode Minimum Current  
Output Voltage Noise (Note 5)  
1.2  
1.1  
1.7  
2.0  
mA  
mA  
V
is Open  
1.5  
1.7  
mA  
mA  
IN  
0.1Hz ≤ f ≤ 10Hz  
10Hz ≤ f ≤ 1kHz  
6.0  
3.5  
µV  
P-P  
6
µV  
RMS  
Long-Term Stablility of Output Voltage (Note 6)  
Temperature Hysteresis of Output (Note 7)  
∆t = 1000Hrs Non-Cumulative  
∆T = ±25°C  
30  
5
ppm  
ppm  
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  
range.  
●
denotes specifications which apply over the specified temperature  
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.  
3
LT1236  
ELECTRICAL CHARACTERISTICS  
VIN = 15V, IOUT = 0, TA = 25°C, unless otherwise noted.  
temperature. Output voltage is always measured at 25°C, but the IC is  
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.  
cycled to 50°C or 0°C 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.  
Note 7: Hysteresis in output voltage is created by package stress that  
differs depending on whether the IC was previously at a higher or lower  
U W  
TYPICAL PERFOR A CE CHARACTERISTICS  
Minimum Input/Output  
Differential, LT1236-10  
Ripple Rejection  
Ripple Rejection  
130  
1.6  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
0
115  
110  
105  
100  
95  
V
C
= 15V  
OUT  
f = 150Hz  
T
= 125 °C  
IN  
J
= 0  
120  
110  
100  
90  
T
= –55 °C  
J
LT1236-10  
LT1236-5  
LT1236-10  
T
= 25 °C  
J
LT1236-5  
80  
70  
90  
60  
50  
85  
25 30  
10 15 20  
INPUT VOLTAGE (V)  
0
5
35 40  
10  
100  
1k  
10k  
0
2
4
10 12 14 16 18 20  
6
8
FREQUENCY (Hz)  
OUTPUT CURRENT (mA)  
LT1236 G02  
LT1236 G01  
LT1236 G03  
Start-Up (Series Mode)  
Start-Up (Shunt Mode), LT1236-10  
Output Voltage Noise Spectrum  
13  
12  
11  
10  
9
11  
10  
9
400  
350  
300  
250  
200  
150  
100  
50  
V
IN  
= 0V TO 12V  
LT1236-10  
LT1236-10  
1k  
V
OUT  
0V  
+ 2V  
V
OUT  
8
OUT  
IN  
GND  
8
NC  
7
LT1236-10  
LT1236-5  
7
6
5
6
LT1236-5  
5
4
0
3
12  
14  
6
10  
12  
1M  
0
2
4
6
8
10  
0
2
4
8
10  
100  
1k  
FREQUENCY (Hz)  
TIME (µs)  
TIME (µs)  
LT1236 G06  
LT1236 G04  
LT1236 G05  
4
LT1236  
U W  
TYPICAL PERFOR A CE CHARACTERISTICS  
Output Voltage Temperature Drift  
LT1236-5  
Output Voltage Noise  
Load Regulation LT1236-5  
5.005  
5.004  
5.003  
5.002  
5.001  
5.000  
16  
14  
12  
10  
8
5
4
C
= 0  
V
= 8V  
OUT  
FILTER = 1 POLE  
= 0.1Hz  
IN  
f
LOW  
3
2
1
0
–1  
– 2  
– 3  
– 4  
– 5  
6
LT1236-10  
LT1236-5  
4
2
0
10  
100  
1k  
10k  
–40  
0
20  
40  
60  
100  
–20  
80  
–10 –8 – 6 – 4 – 2  
SOURCING  
0
2
4
6
8
10  
TEMPERATURE (°C)  
BANDWIDTH (Hz)  
SINKING  
LT1236 G07  
LT1236 G08  
OUTPUT CURRENT (mA)  
LT1236 G09  
Sink Mode* Current Limit,  
LT1236-5  
Quiescent Current, LT1236-5  
Thermal Regulation, LT1236-5  
1.8  
60  
50  
I
= 0  
V
IN  
= 8V  
V
= 25V  
OUT  
IN  
1.6  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
∆POWER = 200mW  
LOAD  
REGULATION  
0
– 0.5  
–1.0  
40  
T
= – 55°C  
J
THERMAL  
REGULATION*  
30  
20  
T
= 25°C  
J
T
= 125°C  
J
I
= 10mA  
LOAD  
10  
0
0
60 80  
TIME (ms)  
0
20 40  
100 120 140  
0
5
10 15 20 25  
INPUT VOLTAGE (V)  
40  
0
2
4
6
8
10 12 14 16 18  
30 35  
OUTPUT VOLTAGE (V)  
LT1236 G10  
*NOTE THAT AN INPUT VOLTAGE IS REQUIRED  
*INDEPENDENT OF TEMPERATURE COEFFICIENT  
FOR 5V UNITS.  
LT1236 G12  
LT1236 G11  
Load Transient Response,  
LT1236-5, CLOAD = 0  
Load Transient Response,  
LT1236-5, CLOAD = 1000pF  
Output Noise 0.1Hz to 10Hz,  
LT1236-5  
FILTERING = 1 ZERO AT 0.1Hz  
2 POLES AT 10Hz  
I
= 0  
I
= 0  
SINK  
SOURCE  
I
= 0  
I
= 0  
SOURCE  
SINK  
5µV (1ppm)  
50mV  
50mV  
20mV  
20mV  
I
= 0.2mA  
I
= 0.2mA  
SINK  
I
= 0.2mA  
SINK  
SOURCE  
I
= 0.5mA  
SOURCE  
I
= 2-10mA  
SINK  
I
= 2-10mA  
I
= 2-10mA  
SINK  
SOURCE  
I
= 2-10mA  
SOURCE  
∆I  
= 100µA  
∆I  
= 100µA  
SOURCE P-P  
∆I  
SINK  
= 100µA  
∆I  
SINK  
= 100µA  
P-P  
SOURCE  
P-P  
P-P  
4
6
0
1
2
3
4
0
1
2
3
4
0
5
10 15 20  
0
5
10 15 20  
0
1
2
3
5
TIME (µs)  
TIME (µs)  
TIME (MINUTES)  
LT1236 G13  
LT1236 G14  
LT1236 G15  
5
LT1236  
U W  
TYPICAL PERFOR A CE CHARACTERISTICS  
Output Voltage Temperature  
Drift, LT1236-10  
Load Regulation, LT1236-10  
Input Supply Current, LT1236-10  
10.0020  
10.0015  
10.0010  
10.0005  
10.0000  
9.9995  
5
4
1.8  
1.6  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
V
= 12V  
I
= 0  
OUT  
IN  
T = – 55°C  
J
3
T = 25°C  
J
2
T = 125°C  
J
1
0
–1  
– 2  
– 3  
– 4  
– 5  
9.9990  
9.9985  
9.9980  
0
–40 –20  
0
20  
40  
60  
80 100  
–10 –8 – 6 – 4 – 2  
SOURCING  
0
2
4
6
8
10  
0
5
10 15 20 25  
INPUT VOLTAGE (V)  
40  
30 35  
TEMPERATURE (˚C)  
SINKING  
LT1236 G16  
OUTPUT CURRENT (mA)  
LT1236 G17  
LT1236 G18  
Shunt Mode Current Limit,  
LT1236-10  
Shunt Characteristics, LT1236-10  
Thermal Regulation, LT1236-10  
1.8  
1.6  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
60  
50  
INPUT PIN OPEN  
INPUT PIN OPEN  
V
= 30V  
IN  
∆POWER = 200mW  
LOAD  
0
REGULATION  
40  
–0.5  
–1.0  
–1.5  
T = – 55°C  
J
30  
20  
THERMAL  
REGULATION*  
T = 25°C  
J
I
= 10mA  
LOAD  
T = 125°C  
10  
0
J
0
60 80  
TIME (ms)  
0
20 40  
100 120 140  
0
2
4
6
8
10 12 14 16 18  
0
2
4
6
10  
12  
8
OUTPUT VOLTAGE (V)  
OUTPUT TO GROUND VOLTAGE (V)  
LT1236 G20  
LT1236 G19  
*INDEPENDENT OF TEMPERATURE COEFFICIENT  
LT1236 G21  
Load Transient Response,  
LT1236-10, CLOAD = 0  
Output Noise 0.1Hz to 10Hz,  
LT1236-10  
Load Transient Response,  
LT1236-10, CLOAD = 1000pF  
FILTERING = 1 ZERO AT 0.1Hz  
2 POLES AT 10Hz  
I
= 0.8mA  
I
= 0.6mA  
SINK  
SINK  
I
= 0  
I
= 0  
SOURCE  
SOURCE  
5mV  
20mV  
50mV  
10µV (1ppm)  
10mV  
I
= 1.2mA  
SINK  
I
= 0.8mA  
SINK  
I
= 0.2mA  
SOURCE  
I
I
= 0.5mA  
SOURCE  
I
I
= 1.4mA  
I
= 1.0mA  
SINK  
SINK  
= 2-10mA  
I
= 2-10mA  
= 2-10mA  
SOURCE  
SINK  
SOURCE  
I
= 2-10mA  
SINK  
∆I  
= 100µA  
P-P  
∆I  
= 100µA  
∆I  
= 100µA  
P-P  
∆I  
= 100µA  
P-P  
SOURCE  
SOURCE  
P-P  
SINK  
SINK  
1
0
1
2
3
4
0
1
2
3
4
0
1
2
3
4
0
2
3
4
4
6
0
1
2
3
5
TIME (µs)  
TIME (µs)  
TIME (MINUTES)  
NOTE VERTICAL SCALE CHANGE  
NOTE VERTICAL SCALE CHANGE  
LT1236 G24  
BETWEEN SOURCING AND SINKING  
BETWEEN SOURCING AND SINKING  
LT1236 G23  
LT1236 G22  
6
LT1236  
U
W U U  
APPLICATIONS INFORMATION  
Effect of Reference Drift on System Accuracy  
in series with a 20kΩ potentiometer will give ±10mV trim  
range. Effect on the output TC will be only 1ppm/°C for the  
±5mV trim needed to set the “A” device to 10.000V.  
A large portion of the temperature drift error budget in  
many systems is the system reference voltage. This graph  
indicates the maximum temperature coefficient allowable  
if the reference is to contribute no more than 0.5LSB error  
to the overall system performance. The example shown is  
a 12-bit system designed to operate over a temperature  
range from 25°C to 65°C. Assuming the system calibra-  
tion is performed at 25°C, the temperature span is 40°C.  
It can be seen from the graph that the temperature coeffi-  
cient of the reference must be no worse than 3ppm/°C if  
it is to contribute less than 0.5LBS error. For this reason,  
the LT1236 family has been optimized for low drift.  
LT1236-5  
The LT1236-5 does have an output voltage trim pin, but  
the TC of the nominal 4V open circuit voltage at pin 5 is  
about –1.7mV/°C. For the voltage trimming not to affect  
reference output TC, the external trim voltage must track  
thevoltageonthetrimpin. Inputimpedanceofthetrimpin  
is about 100kΩ and attenuation to the output is 13:1. The  
technique shown below is suggested for trimming the  
output of the LT1236-5 while maintaining minimum shift  
in output temperature coefficient. The R1/R2 ratio is  
chosen to minimize interaction of trimming and TC shifts,  
so the exact values shown should be used.  
Maximum Allowable Reference Drift  
100  
8-BIT  
LT1236-5  
V
IN  
GND TRIM  
10-BIT  
OUT  
OUT  
10  
R1  
27k  
R2  
50k  
12-BIT  
14-BIT  
1N4148  
LT1236 AI02  
1.0  
10 20  
40  
60 70 80  
100  
90  
30  
50  
TEMPERATURE SPAN (°C)  
Capacitive Loading and Transient Response  
LT1236 AI01  
The LT1236 is stable with all capacitive loads, but for  
optimum settling with load transients, output capacitance  
shouldbeunder1000pF. Theoutputstageofthereference  
is class AB with a fairly low idling current. This makes  
transient response worse-case at light load currents.  
Because of internal current drain on the output, actual  
Trimming Output Voltage  
TheLT1236-10hasatrimpinforadjustingoutputvoltage.  
The impedance of the trim pin is about 12kΩ with a  
nominal open circuit voltage of 5V. It is designed to be  
driven from a source impedance of 3kΩ or less to mini-  
mize changes in the LT1236 TC with output trimming.  
Attenuation between the trim pin and the output is 70:1.  
This allows ±70mV trim range when the trim pin is tied to  
the wiper of a potentiometer connected between the  
output and ground. A 10kΩ potentiometer is recom-  
mended, preferably a 20 turn cermet type with stable  
characteristics over time and temperature.  
worst-case occurs at ILOAD = 0 on LT1236-5 and ILOAD  
=
1.4mA (sinking) on LT1236-10. Significantly better load  
transient response is obtained by moving slightly away  
from these points. See Load Transient Response curves  
for details. In general, best transient response is obtained  
when the output is sourcing current. In critical applica-  
tions, a 10µF solid tantalum capacitor with several ohms  
in series provides optimum output bypass.  
The LT1236-10 “A” version is pre-trimmed to ±5mV and  
therefore can utilize a restricted trim range. A 75k resistor  
7
LT1236  
U
W U U  
APPLICATIONS INFORMATION  
Kelvin Connections  
temperature gradients in the package leads. Variations in  
thermal resistance, caused by uneven air flow, create  
differential lead temperatures, thereby causing thermo-  
electric voltage noise at the output of the reference.  
Although the LT1236 does not have true force/sense  
capabilityatitsoutputs,significantimprovementsinground  
loop and line loss problems can be achieved with proper  
hook-up. In series mode operation, the ground pin of the  
LT1236 carries only ≈ 1mA and can be used as a sense  
line, greatly reducing ground loop and loss problems on  
the low side of the reference. The high side supplies load  
current so line resistance must be kept low. Twelve feet of  
#22 gauge hook-up wire or 1 foot of 0.025 inch printed  
circuit trace will create 2mV loss at 10mA output current.  
This is equivalent to 1LSB in a 10V, 12-bit system.  
Standard Series Mode  
LT1236  
KEEP THIS LINE RESISTANCE LOW  
INPUT  
IN  
OUT  
+
GND  
LOAD  
GROUND  
RETURN  
The following circuits show proper hook-up to minimize  
errors due to ground loops and line losses. Losses in the  
output lead can be greatly reduced by adding a PNP boost  
transistor if load currents are 5mA or higher. R2 can be  
added to further reduce current in the output sense lead.  
LT1236 AI03  
Series Mode with Boost Transistor  
INPUT  
R1  
220Ω  
2N3906  
Effects of Air Movement on Low Frequency Noise  
IN  
TheLT1236hasverylownoisebecauseoftheburiedzener  
usedinitsdesign.Inthe0.1Hzto10Hzband,peak-to-peak  
noise is about 0.5ppm of the DC output. To achieve this  
low noise, however, care must be taken to shield the  
reference from ambient air turbulence. Air movement can  
create noise because of thermoelectric differences be-  
tweenICpackageleadsandprintedcircuitboardmaterials  
and/or sockets. Power dissipation in the reference, even  
though it rarely exceeds 20mW, is enough to cause small  
LT1236  
OUT  
LOAD  
GND  
R2*  
GROUND  
RETURN  
*OPTIONAL—REDUCES CURRENT IN OUTPUT SENSE  
LEAD: R2 = 2.4k (LT1236-5), 5.6k (LT1236-10)  
LT1236 AI04  
U
TYPICAL APPLICATIONS  
Restricted Trim Range for Improved  
Resolution, 10V, “A” Version Only  
LT1236-10 Full Trim Range (±0.7%)  
Negative Series Reference  
15V  
LT1236-10  
R1  
LT1236-10  
4.7k  
LT1236A-10  
V
V
OUT  
IN  
GND TRIM  
OUT  
IN  
V
10.000V  
IN  
GND TRIM  
OUT  
IN  
IN  
OUT  
D1  
15V  
GND  
R2  
4.7k  
R1  
75k  
R1*  
10k  
R2  
50k  
–10V AT  
50mA  
–15V  
Q1  
2N2905  
LT1236 TA03  
LT1236 TA04  
*CAN BE RAISED TO 20k FOR LESS  
CRITICAL APPLICATIONS  
LT1236 TA10  
TRIM RANGE ≈ ±10mV  
8
LT1236  
U
TYPICAL APPLICATIONS  
Boosted Output Current  
Boosted Output Current  
with Current Limit  
with No Current Limit  
±10V Output Reference  
+
+
V
≥ (V  
+ 1.8V)  
V
≥ V  
OUT  
+ 2.8V  
OUT  
LT1236-10  
D1*  
LED  
R1  
220Ω  
R1  
220Ω  
8.2Ω  
15V  
V
V
+10V  
COM  
IN  
OUT  
2N2905  
2N2905  
GND  
IN  
LT1236  
OUT  
IN  
LT1236  
OUT  
10V AT  
100mA  
10V AT  
100mA  
LT1236-10  
V
GND  
+
2µF  
SOLID  
TANT  
GND  
V
IN  
OUT  
+
2µF  
SOLID  
TANT  
GND  
–10V  
LT1236 TA05  
I
–15V –10V  
LOAD  
*GLOWS IN CURRENT LIMIT,  
DO NOT OMIT  
R1=  
R1  
–15V  
LT1236 TA06  
I
+ 1.5mA  
LOAD  
LT1236 TA17  
Handling Higher Load Currents  
Operating 5V Reference from 5V Supply  
15V  
5V LOGIC  
SUPPLY  
30mA  
1N914  
CMOS LOGIC GATE**  
≥ 2kHz*  
R1*  
IN  
LT1236-5  
1N914  
169Ω  
+
≈8.5V  
5V  
LT1236-10  
f
IN  
OUT  
IN  
REFERENCE  
V
10V  
+
OUT  
OUT  
C2*  
5µF  
GND  
C1*  
5µF  
GND  
TYPICAL LOAD  
CURRENT = 30mA  
R
L
*FOR HIGHER FREQUENCIES C1 AND C2 MAY BE DECREASED  
**PARALLEL GATES FOR HIGHER REFERENCE CURRENT LOADING  
LT1236 TA15  
*SELECT R1 TO DELIVER TYPICAL LOAD CURRENT.  
LT1236 WILL THEN SOURCE OR SINK AS NECESSARY  
TO MAINTAIN PROPER OUTPUT. DO NOT REMOVE LOAD  
AS OUTPUT WILL BE DRIVEN UNREGULATED HIGH. LINE  
REGULATION IS DEGRADED IN THIS APPLICATION  
LT1236 TA07  
Trimming 10V Units to 10.24V  
CMOS DAC with Low Drift Full-Scale Trimming**  
LT1236-10  
R3  
4.02K  
1%  
V
IN  
IN  
TRIM GND  
OUT  
V
= 10.24V  
OUT  
OUT  
R4*  
100Ω  
LT1236-10  
TRIM  
GND  
FB  
I
FULL-SCALE  
ADJUST  
R1  
4.99k  
1%  
30pF  
CMOS  
DAC  
LTC7543  
4.32k  
5k  
OUT  
–
+
10V  
F.S.  
REF  
LT1007C  
R2  
40.2Ω  
1%  
V– = –15V*  
*MUST BE WELL REGULATED  
dV  
1.2k  
–15V  
*TC LESS THAN 200ppm/°C  
**NO ZERO ADJUST REQUIRED  
15mV  
V
OUT  
=
dV–  
LT1236 TA14  
WITH LT1007 (V ≤ 60µV)  
0S  
LT1236 TA11  
9
LT1236  
TYPICAL APPLICATIONS  
U
Negative Shunt Reference Driven  
by Current Source  
Strain Gauge Conditioner for 350Ω Bridge  
R1  
357Ω  
1/2W  
LT1236-10  
28mA  
OUT  
GND  
LT1236-10  
28.5mA  
15V  
IN  
OUT  
5V  
–10V (I  
≤ 1mA)  
350Ω STRAIN  
GND  
LOAD  
R3  
GAUGE BRIDGE**  
2M  
2.5mA  
R2  
20k  
2
3
+
3
–
+
LM334  
6
6
V
LM301A†  
R4  
20k  
OUT  
LT1012C  
X100  
–
2
1
R5  
2M  
27Ω  
100pF  
8
R6*  
2M  
–11V TO –40V  
–5V  
LT1236 TA13  
357Ω  
1/2W  
–15V  
**BRIDGE IS ULTRA-LINEAR WHEN ALL LEGS ARE  
*THIS RESISTOR PROVIDES POSITIVE FEEDBACK TO  
THE BRIDGE TO ELIMINATE LOADING EFFECT OF  
ACTIVE, TWO IN COMPRESSION AND TWO IN TENSION,  
OR WHEN ONE SIDE IS ACTIVE WITH ONE COMPRESSED  
AND ONE TENSIONED LEG  
THE AMPLIFIER. EFFECTIVE Z OF AMPLIFIER  
IN  
STAGE IS ≥ 1MΩ. IF R2 TO R5 ARE CHANGED,  
†OFFSET AND DRIFT OF LM301A ARE VIRTUALLY  
ELIMINATED BY DIFFERENTIAL CONNECTION OF LT1012C  
SET R6 = R3  
LT1236 TA08  
2-Pole Lowpass Filtered Reference  
Precision DAC Reference with System TC Trim  
1µF  
V
IN  
MYLAR  
LT1236-10  
IN  
15V  
OUT  
–
GND  
8.87k  
1%  
V
LT1236  
IN  
LT1001  
REF  
OUT  
+
V
IN  
R1  
36k  
R2  
36k  
50k  
ROOM TEMP  
TRIM  
GND  
D1  
TOTAL NOISE  
0.5µF  
MYLAR  
1N457  
10k  
1%  
≤2µV  
f = 10Hz  
RMS  
10.36k  
1%  
1Hz ≤ f ≤ 10kHz  
50k  
TC TRIM*  
1.24k  
1%  
200k  
1%  
D2  
1N457  
10k  
1%  
–V  
REF  
LT1236 TA12  
50k  
8.45k  
1mA  
*TRIMS 1mA REFERENCE CURRENT  
TC BY ±40ppm/°C. THIS TRIM  
DAC  
SCHEME HAS VERY LITTLE EFFECT ON ROOM  
TEMPERATURE CURRENT TO MINIMIZE ITERATIVE  
TRIMMING  
LT1236 TA16  
10  
LT1236  
U
TYPICAL APPLICATIONS  
Ultra-Linear Platinum Temperature Sensor*  
LT1236-10  
20V  
IN  
OUT  
GND  
R2*  
5k  
R10  
182k  
1%  
R14  
5k  
R1**  
253k  
R11  
6.65M  
1%  
R15  
10k  
R8  
10M  
R **  
f
654k  
R9  
100k  
R12  
1k  
R13  
24.3k  
20V  
7
2
R5  
200k  
1%  
–
+
R4  
4.75k  
1%  
R3**  
5k  
6
V
=100mV/°C  
OUT  
LT1001  
–50°C ≤ T ≤ 150°C  
3
4
†
R
S
100Ω AT  
0°C  
–15V  
R6  
619k  
1%  
†STANDARD INDUSTRIAL 100Ω PLATINUM 4-WIRE SENSOR,  
ROSEMOUNT 78S OR EQUIVALENT. α = 0.00385  
TRIM R9 FOR V  
TRIM R12 FOR V  
TRIM R14 FOR V  
R7  
392k  
1%  
= 0V AT 0°C  
= 10V AT 100°C  
= 5V AT 50°C  
OUT  
OUT  
OUT  
USE TRIM SEQUENCE AS SHOWN. TRIMS ARE NONINTERACTIVE  
SO THAT ONLY ONE TRIM SEQUENCE IS NORMALLY REQUIRED.  
–15V  
*FEEDBACK LINEARIZES OUTPUT TO ± 0.005°C FROM  
–50°C TO 150°C  
LT1236 TA09  
**WIREWOUND RESISTORS WITH LOW TC  
U
W
EQUIVALE T SCHE ATIC  
INPUT  
Q3  
D1  
D2  
OUTPUT  
D3  
R1  
Q1  
+
–
A1  
R2  
D4  
6.3V  
Q2  
GND  
LT1236 ES  
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 represen-  
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.  
11  
LT1236  
U
Dimensions in inches (millimeters) unless otherwise noted.  
PACKAGE DESCRIPTION  
N8 Package  
8-Lead Plastic DIP  
0.400*  
(10.160)  
MAX  
0.130 ± 0.005  
0.300 – 0.325  
0.045 – 0.065  
(3.302 ± 0.127)  
(1.143 – 1.651)  
(7.620 – 8.255)  
8
1
7
6
5
0.065  
(1.651)  
TYP  
0.255 ± 0.015*  
(6.477 ± 0.381)  
0.009 – 0.015  
(0.229 – 0.381)  
0.125  
0.015  
(0.380)  
MIN  
(3.175)  
MIN  
+0.025  
–0.015  
0.045 ± 0.015  
(1.143 ± 0.381)  
2
4
3
0.325  
+0.635  
8.255  
(
)
–0.381  
0.100 ± 0.010  
(2.540 ± 0.254)  
0.018 ± 0.003  
(0.457 ± 0.076)  
N8 0395  
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.  
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm).  
S8 Package  
8-Lead Plastic SOIC  
0.189 – 0.197*  
(4.801 – 5.004)  
0.010 – 0.020  
(0.254 – 0.508)  
7
5
8
6
× 45°  
0.004 – 0.010  
(0.101 – 0.254)  
0.053 – 0.069  
(1.346 – 1.752)  
0.008 – 0.010  
(0.203 – 0.254)  
0°– 8° TYP  
0.150 – 0.157*  
(3.810 – 3.988)  
0.228 – 0.244  
(5.791 – 6.197)  
0.016 – 0.050  
0.406 – 1.270  
0.050  
(1.270)  
BSC  
0.014 – 0.019  
(0.355 – 0.483)  
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.  
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm).  
1
3
4
2
SO8 0294  
RELATED PARTS  
PART NUMBER  
DESCRIPTION  
COMMENTS  
LT1019  
Precision Bandgap Reference  
Precision 5V Reference  
0.05%, 5ppm/°C  
0.02%, 2ppm/°C  
LT1027  
LT/GP 0695 10K • PRINTED IN USA  
Linear Technology Corporation  
1630 McCarthy Blvd., Milpitas, CA 95035-7487  
12  
●
●
(408) 432-1900 FAX: (408) 434-0507 TELEX: 499-3977  
LINEAR TECHNOLOGY CORPORATION 1995  

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