LT1236 - Precision Reference - Analog Devices

1 1LT1236 Precision ReferenceUAOPPLICATITYPICALDUESCRIPTIOTh e LT 1236 is a Precision Reference that combines ultra-low drift and noise with excellent long-term stability andhigh output accuracy. The Reference output will bothsource and sink up to 10mA and is almost totally immuneto input voltage variations. Two voltages are available: 5 Vand 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 hasbeen taken to minimize thermal regulation effects andtemperature induced LT1236 combines both superior accuracy and tem-perature coefficient specifications without the use of highpower, on-chip heaters.

2 The LT1236 references are basedon a buried zener diode structure which eliminates noiseand stability problems with surface breakdown , a subsurface zener exhibits better temperaturedrift and time stability than even the best Drift: 5ppm/ C MaxnTrimmed to High Accuracy: MaxnIndustrial Temperature Range SO PackagenOperates in Series or Shunt ModenPin Compatible with AD586, AD587nOutput Sinks and Sources in Series ModenVery Low Noise < 1ppm P-P ( to 10Hz)n100% Noise Testedn> 100dB Ripple RejectionnMinimum Input/Output Differential of 1V, LTC and LT are registered trademarks of Linear Technology Distribution of Temperature DriftBasic positive and Negative ConnectionsLT1236 OUT IN GND LT1236 -10 OUT IN GND VOUT VOUTVINNCR1 = VOUT (V )ILOAD + 15V (V )

3 R1LT1236 TA01 OUTPUT DRIFT (ppm/ C) 30 UNITS (%)4812162422 2 101LT1236 TA02232018141062 DISTRIBUTION OF THREE RUNSUSAOPPLICATInA/D and D/A ConvertersnPrecision RegulatorsnPrecision ScalesnInertial Navigation SystemsnDigital Voltmeters2LT12361 2 3 48 7 6 5 TOP VIEWNC* VIN NC* GNDNC* NC* V0UT TRIM**S8 PACKAGE 8-LEAD PLASTIC SOCONNECTED INTERNALLY. D0 NOT CONNECT EXTERNAL CIRCUITRY TO THESE PINS SEE APPLICATIONS INFORMATION SECTION* ** AUGWAWUWARBSOLUTEXITISI nput voltage .. 40 VInput/Output voltage Differential.

4 35 VOutput-to-Ground voltage (Shunt Mode Current Limit) LT1236 -5 .. 10 VLT1236-10 .. 16 VTrim Pin-to-Ground VoltagePositive .. Equal to VOUTN egative .. 20 VOutput Short-Circuit DurationVIN = 35V .. 10 secVIN 20V .. IndefiniteOperating Temperature RangeLT1236AC, BC, CC .. 0 C to 70 CLT1236AI, BI, CI .. 40 C to 85 CStorage Temperature Range .. 65 C to 150 CLead Temperature (Soldering, 10 sec) .. 300 CWUUPACKAGE/ORDER I FOR ATIOC onsult factory for Military grade CCHARA TERISTICSVIN = 10V, IOUT = 0, TA = 25 C, unless otherwise voltage (Note 1) voltage Temperature Coefficient (Note 2)TMIN TJ TMAXLT1236A-525ppm/ CLT1236B-5510ppm/ CLT1236C-51015ppm/ CLine Regulation (Note 3) VIN 10V412ppm/Vl20ppm/V10V VIN 40V26ppm/Vl10ppm/VLoad Regulation (Sourcing Current)0 IOUT 10mA1020ppm/mA(Note 3)

5 L35ppm/mALT1236 AIS8-5LT1236 BIS8-5LT1236 CIS8-5LT1236 AIS8-10LT1236 BIS8-10LT1236 CIS8-10 ORDER PARTNUMBERS8 PART MARKINGLT1236 ACS8-5LT1236 BCS8-5LT1236 CCS8-5LT1236 ACS8-10LT1236 BCS8-10LT1236 CCS8-10236AC5236BC5236CC5236AC1236BC1236 CC1236AI5236BI5236CI5236AI1236BI1236CI1 TJMAX = 125 C, JA = 190 C/WTJMAX = 125 C, JA = 130 C/WORDER PARTNUMBERLT1236 ACN8-5LT1236 BCN8-5LT1236 CCN8-5LT1236 ACN8-10LT1236 BCN8-10LT1236 CCN8-10LT1236 AIN8-5LT1236 BIN8-5LT1236 CIN8-5LT1236 AIN8-10LT1236 BIN8-10LT1236 CIN8-101 2 3 48 7 6 5 TOP VIEWNC* VIN NC* GNDNC* NC* V0UT TRIM**N8 PACKAGE 8-LEAD PDIP CONNECTED INTERNALLY.

6 D0 NOT CONNECT EXTERNAL CIRCUITRY TO THESE PINS SEE APPLICATIONS INFORMATION SECTION* ** 3LT1236 ELECTRICAL CCHARA TERISTICSVIN = 10V, IOUT = 0, TA = 25 C, unless otherwise Output voltage (Note 1) voltage Temperature Coefficient (Note 2)TMIN TJ TMAXLT1236A-1025ppm/ CLT1236B-10510ppm/ CLT1236C-101015ppm/ CLine Regulation (Note 3) VIN VIN Regulation (Sourcing Current)0 IOUT 10mA1225ppm/mA(Note 3)l40ppm/mALoad Regulation (Shunt Mode) ISHUNT 10mA50100ppm/mA(Notes 3, 4)l150ppm/mASeries Mode Supply Mode Minimum CurrentVIN is voltage Noise (Note 5) f VP-P10Hz f VRMSLong-Term Stablility of Output voltage (Note 6) t = 1000 Hrs Non-Cumulative30ppmTemperature Hysteresis of Output (Note 7) T = 25 C5ppmVIN = 15V, IOUT = 0, TA= 25 C, unless otherwise 5: RMS noise is measured with a 2-pole highpass filter at 10Hz and a2-pole lowpass filter at 1kHz.

7 The resulting output is full-wave rectified andthen integrated for a fixed period, making the final reading an average asopposed to RMS. Correction factors are used to convert from average toRMS, and is used to correct for the non-ideal bandbass of the noise is measured with a single highpass filter at and a2-pole lowpass filter at 10Hz. The unit is enclosed in a still-air environmentto eliminate thermocouple effects on the leads. Test time is 10 6: Long-term stability typically has a logarithmic characteristic andtherefore, changes after 1000 hours tend to be much smaller than beforethat time.

8 Total drift in the second thousand hours is normally less thanone third that of the first thousand hours, with a continuing trend towardreduced drift with time. Significant improvement in long-term drift can beThe l denotes specifications which apply over the specified 1: Output voltage is measured immediately after turn-on. Changesdue to chip warm-up are typically less than 2: Temperature coefficient is measured by dividing the change inoutput voltage over the temperature range by the change in slope is also measured at 25 3: Line and load regulation are measured on a pulse basis.

9 Outputchanges due to die temperature change must be taken into 4: Shunt mode regulation is measured with the input open. With theinput connected, shunt mode current can be reduced to 0mA. Loadregulation will remain the Regulation (Sinking Current)0 IOUT 10mA60100ppm/mA(Note 3)l150ppm/mASupply voltage f VP-P(Note 5)10Hz f VRMSLong-Term Stability of Output voltage (Note 6) t = 1000 Hrs Non-Cumulative20ppmTemperature Hysteresis of Output (Note 7) T = 25 C10ppm4LT1236 ELECTRICAL CCHARA TERISTICSVIN = 15V, IOUT = 0, TA = 25 C, unless otherwise by preconditioning the IC with a 100-200 hour, 125 C burn term stability will also be affected by differential stresses between theIC and the board material created during board assembly.

10 Temperaturecycling and baking of completed boards is often used to reduce thesestresses in critical 7: Hysteresis in output voltage is created by package stress thatdiffers depending on whether the IC was previously at a higher or lowertemperature. Output voltage is always measured at 25 C, but the IC iscycled to 50 C or 0 C before successive measurements. Hysteresis isroughly proportional to the square of temperature change. Hysteresis isnot normally a problem for operational temperature excursions, but can besignificant in critical narrow temperature range applications where theinstrument might be stored at high or low TERISTICSUWATYPICALPERFORCER ipple RejectionINPUT voltage (V)085 REJECTION (dB)909510010510203040LT1236 G011101155152535f = 150 HzLT1236-5LT1236-10 FREQUENCY (Hz)1090 REJECTION (dB)