LT1236 Precision Reference FEATURES DESCRIPTIOU n Ultra-Low Drift: 5ppm/(cid:176) C Max The LT®1236 is a precision reference that combines ultra- n Trimmed to High Accuracy: 0.05% Max low drift and noise with excellent long-term stability and n Industrial Temperature Range SO Package high output accuracy. The reference output will both n Operates in Series or Shunt Mode source and sink up to 10mA and is almost totally immune n Pin Compatible with AD586, AD587 to input voltage variations. Two voltages are available: 5V n Output Sinks and Sources in Series Mode and 10V. The 10V version can be used as a shunt regulator n Very Low Noise < 1ppm (0.1Hz to 10Hz) (two-terminal zener) with the same precision characteris- P-P n 100% Noise Tested tics as the three-terminal connection. Special care has n > 100dB Ripple Rejection been taken to minimize thermal regulation effects and n Minimum Input/Output Differential of 1V temperature induced hysteresis. The LT1236 combines both superior accuracy and tem- APPLICATIOUS perature coefficient specifications without the use of high power, on-chip heaters. The LT1236 references are based n A/D and D/A Converters on a buried zener diode structure which eliminates noise n Precision Regulators and stability problems with surface breakdown devices. n Precision Scales Further, a subsurface zener exhibits better temperature n Inertial Navigation Systems drift and time stability than even the best band-gap n Digital Voltmeters references. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIOU Basic Positive and Negative Connections Typical Distribution of Temperature Drift 24 (cid:13) (cid:13) DISTRIBUTION (cid:13) 22 OF THREE RUNS LT1236 LT1236-10 20 VIN IN OUT VOUT NC IN OUT 18 GND GND 16 %) 14 –VOUT S ( 12 R1 = ILVOOAUDT +– 1(.V5–m)A R1 UNIT 10 8 –15V(cid:13) 6 (V–) 4 LT1236 TA01 2 0 –3 –2 –1 0 1 2 3 OUTPUT DRIFT (ppm/°C) LT1236 TA02 1

LT1236 ABSOLUTE WAXIWUW RATIUGS Input Voltage .......................................................... 40V Output Short-Circuit Duration Input/Output Voltage Differential ............................ 35V V = 35V......................................................... 10 sec IN Output-to-Ground Voltage (Shunt Mode Current Limit) V £ 20V ................................................... Indefinite IN LT1236-5............................................................. 10V Operating Temperature Range LT1236-10........................................................... 16V LT1236AC, BC, CC.................................. 0(cid:176) C to 70(cid:176) C Trim Pin-to-Ground Voltage LT1236AI, BI, CI................................ –40(cid:176) C to 85(cid:176) C Positive................................................ Equal to V Storage Temperature Range................ –65(cid:176) C to 150(cid:176) C OUT Negative ........................................................... – 20V Lead Temperature (Soldering, 10 sec)................ 300(cid:176) C PACKAGE/ORDER IUFORWATIOU ORDER PART ORDER PART NUMBER NUMBER TOP VIEW LT1236ACN8-5 TOP VIEW LT1236ACS8-5 LT1236AIS8-5 NC*(cid:13) 1(cid:13) 8(cid:13) NC*(cid:13) LT1236BCN8-5 NC*(cid:13) 1(cid:13) 8(cid:13) NC*(cid:13) LT1236BCS8-5 LT1236BIS8-5 VIN(cid:13) 2(cid:13) 7(cid:13) NC*(cid:13) LT1236CCN8-5 VIN(cid:13) 2(cid:13) 7(cid:13) NC*(cid:13) LT1236CCS8-5 LT1236CIS8-5 LT1236ACN8-10 LT1236ACS8-10 LT1236AIS8-10 NC*(cid:13) 3(cid:13) 6(cid:13) V0UT(cid:13) NC*(cid:13) 3(cid:13) 6(cid:13) V0UT(cid:13) LT1236BCN8-10 LT1236BCS8-10 LT1236BIS8-10 GND 4 5(cid:13) TRIM** GND 4 5(cid:13) TRIM** LT1236CCN8-10 LT1236CCS8-10 LT1236CIS8-10 (cid:13) (cid:13) N8 PACKAGE(cid:13) LT1236AIN8-5 S8 PACKAGE(cid:13) 8-LEAD PDIP(cid:13) 8-LEAD PLASTIC SO *C(cid:13) ONNECTED (cid:13)INTERNALLY. (cid:13) LT1236BIN8-5 *C(cid:13) ONNECTED INTERNALLY. (cid:13) S8 PART MARKING D(cid:13) 0 NOT CONNECT EXTERNAL(cid:13) LT1236CIN8-5 D(cid:13) 0 NOT CONNECT EXTERNAL(cid:13) C(cid:13) IRCUITRY TO THESE PINS(cid:13) C(cid:13) IRCUITRY TO THESE PINS(cid:13) 236AC5 236AI5 LT1236AIN8-10 **S(cid:13) EE APPLICATIONS(cid:13) **S(cid:13) EE APPLICATIONS(cid:13) 236BC5 236BI5 I(cid:13)NFORMATION SECTION LT1236BIN8-10 I(cid:13)NFORMATION SECTION TJMAX = 125(cid:176)C, q JA = 130(cid:176)C/W LT1236CIN8-10 TJ(cid:13)(cid:13)MAX = 125(cid:176)C, q JA = 190(cid:176)C/W 236CC5 236CI5 236AC1 236AI1 (cid:13) 236BC1 236BI1 236CC1 236CI1 Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS V = 10V, I = 0, T = 25(cid:176) C, unless otherwise noted. IN OUT A 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 £ T £ T MIN J MAX LT1236A-5 2 5 ppm/(cid:176) C LT1236B-5 5 10 ppm/(cid:176) C LT1236C-5 10 15 ppm/(cid:176) C Line Regulation (Note 3) 7.2V £ V £ 10V 4 12 ppm/V IN l 20 ppm/V 10V £ V £ 40V 2 6 ppm/V IN l 10 ppm/V Load Regulation (Sourcing Current) 0 £ I £ 10mA 10 20 ppm/mA OUT (Note 3) l 35 ppm/mA 2

LT1236 ELECTRICAL CHARACTERISTICS V = 10V, I = 0, T = 25(cid:176) C, unless otherwise noted. IN OUT A LT1236-5 PARAMETER CONDITIONS MIN TYP MAX UNITS Load Regulation (Sinking Current) 0 £ I £ 10mA 60 100 ppm/mA OUT (Note 3) l 150 ppm/mA Supply Current 0.8 1.2 mA l 1.5 mA Output Voltage Noise 0.1Hz £ f £ 10Hz 3.0 m V P-P (Note 5) 10Hz £ f £ 1kHz 2.2 3.5 m V RMS Long-Term Stability of Output Voltage (Note 6) D t = 1000Hrs Non-Cumulative 20 ppm Temperature Hysteresis of Output (Note 7) D T = – 25(cid:176) C 10 ppm V = 15V, I = 0, T = 25(cid:176) C, unless otherwise noted. IN OUT A 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 £ T £ T MIN J MAX LT1236A-10 2 5 ppm/(cid:176) C LT1236B-10 5 10 ppm/(cid:176) C LT1236C-10 10 15 ppm/(cid:176) C Line Regulation (Note 3) 11.5V £ V £ 14.5V 1.0 4 ppm/V IN l 6 ppm/V 14.5V £ V £ 40V 0.5 2 ppm/V IN l 4 ppm/V Load Regulation (Sourcing Current) 0 £ I £ 10mA 12 25 ppm/mA OUT (Note 3) l 40 ppm/mA Load Regulation (Shunt Mode) 1.7mA £ I £ 10mA 50 100 ppm/mA SHUNT (Notes 3, 4) l 150 ppm/mA Series Mode Supply Current 1.2 1.7 mA l 2.0 mA Shunt Mode Minimum Current V is Open 1.1 1.5 mA IN l 1.7 mA Output Voltage Noise (Note 5) 0.1Hz £ f £ 10Hz 6.0 m V P-P 10Hz £ f £ 1kHz 3.5 6 m V RMS Long-Term Stablility of Output Voltage (Note 6) D t = 1000Hrs Non-Cumulative 30 ppm Temperature Hysteresis of Output (Note 7) D T = – 25(cid:176) C 5 ppm The l denotes specifications which apply over the specified temperature Note 5: RMS noise is measured with a 2-pole highpass filter at 10Hz and a range. 2-pole lowpass filter at 1kHz. The resulting output is full-wave rectified and Note 1: Output voltage is measured immediately after turn-on. Changes then integrated for a fixed period, making the final reading an average as due to chip warm-up are typically less than 0.005%. 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. Note 2: Temperature coefficient is measured by dividing the change in output voltage over the temperature range by the change in temperature. Peak-to-peak noise is measured with a single highpass filter at 0.1Hz and a Incremental slope is also measured at 25(cid:176) C. 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 3: Line and load regulation are measured on a pulse basis. Output changes due to die temperature change must be taken into account Note 6: Long-term stability typically has a logarithmic characteristic and separately. 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 Note 4: Shunt mode regulation is measured with the input open. With the one third that of the first thousand hours, with a continuing trend toward input connected, shunt mode current can be reduced to 0mA. Load reduced drift with time. Significant improvement in long-term drift can be regulation will remain the same. 3

LT1236 ELECTRICAL CHARACTERISTICS V = 15V, I = 0, T = 25(cid:176) C, unless otherwise noted. IN OUT A realized by preconditioning the IC with a 100-200 hour, 125(cid:176) C burn in. temperature. Output voltage is always measured at 25(cid:176) C, but the IC is Long term stability will also be affected by differential stresses between the cycled to 50(cid:176) C or 0(cid:176) C before successive measurements. Hysteresis is IC and the board material created during board assembly. Temperature roughly proportional to the square of temperature change. Hysteresis is cycling and baking of completed boards is often used to reduce these not normally a problem for operational temperature excursions, but can be stresses in critical applications. significant in critical narrow temperature range applications where the Note 7: Hysteresis in output voltage is created by package stress that instrument might be stored at high or low temperatures. differs depending on whether the IC was previously at a higher or lower TYPICAL PERFORWAUCE CHARACTERISTICS Minimum Input/Output Ripple Rejection Ripple Rejection Differential, LT1236-10 115 130 1.6 f = 150Hz VIN = 15V(cid:13) TJ = 125 °C 120 COUT = 0 1.4 110 TION (dB)110005 LT1236-10 TION (dB) 11019000 LT1236-10 UT VOLTAGE (V) 101...280 TJ = –55 °C TJ = 25 °C REJEC 95 LT1236-5 REJEC 80 LT1236-5 T/OUTP 0.6 70 PU 0.4 N 90 I 60 0.2 85 50 0 0 5 10 15 20 25 30 35 40 10 100 1k 10k 0 2 4 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V) FREQUENCY (Hz) OUTPUT CURRENT (mA) LT1236 G01 LT1236 G02 LT1236 G03 Start-Up (Series Mode) Start-Up (Shunt Mode), LT1236-10 Output Voltage Noise Spectrum 13 11 400 VIN = 0V TO 12V 12 LT1236-10 350 10 11 V) 10 LT1236-10 V) Hz)300 OLTAGE ( 98 OLTAGE ( 89 0VVOUT + 2V 1k OUT VOUT (cid:214)AGE (nV/220500 UTPUT V 67 UTPUT V 7 NC ING N(cid:13)D SE VOLT150 LT1236-10 O LT1236-5 O NOI100 LT1236-5 5 6 50 4 3 5 0 (cid:13) 0 2 4 6 8 10 12 14 (cid:13) 0 2 4 6 8 10 12 10 100 1k 1M TIME (µs) TIME (m s) FREQUENCY (Hz) LT1236 G04 LT1236 G05 LT1236 G06(cid:13)(cid:13) 4

LT1236 TYPICAL PERFORWAUCE CHARACTERISTICS Output Voltage Temperature Drift Output Voltage Noise LT1236-5 Load Regulation LT1236-5 16 5.005 5 COUT = 0(cid:13) VIN = 8V FILTER = 1 POLE(cid:13) 4 14 fLOW = 0.1Hz 5.004 3 12 mRMS NOISE (V) 10648 LT1236-10 OUTPUT VOLTAGE (V)55..000032 OUTPUT CHANGE (mV) ––20211 5.001 –3 2 –4 LT1236-5 0 5.000 –5 10 100 1k 10k –40 –20 0 20 40 60 80 100 –10 –8 –6 –4 –2 0 2 4 6 8 10 BANDWIDTH (Hz) TEMPERATURE (°C) SOURCING SINKING LT1236 G07 LT1236 G08 OUTPUT CURRENT (mA) LT1236 G09 Sink Mode* Current Limit, Quiescent Current, LT1236-5 LT1236-5 Thermal Regulation, LT1236-5 1.8 60 (cid:13) IOUT = 0 VIN = 8V VIN = 25V(cid:13) 1.6 D POWER = 200mW 50 UT CURRENT (mA) 01110.....80246 TTTJJJ === –1225555°°C°CC NT INTO OUTPUT (mA) 423000 TPUT CHANGE (mV) ––10..050(cid:13)(cid:13) LROEAGDU(cid:13)LATION TRHEEGRUMLAATLI O(cid:13) N* P E U IN 0.4 CURR 10 O (cid:13) ILOAD = 10mA 0.2 (cid:13) 0 0 (cid:13) 0 5 10 15 20 25 30 35 40 0 2 4 6 8 10 12 14 16 18 (cid:13) 0 20 40 60 80 100 120 140 INPUT VOLTAGE (V) OUTPUT VOLTAGE (V) TIME (ms) LT1236 G10 *NOTE THAT AN INPUT VOLTAGE IS REQUIRED (cid:13) *INDEPENDENT OF TEMPERATURE COEFFICIENT FOR 5V UNITS. LT1236 G11 LT1236 G12 Load Transient Response, Load Transient Response, Output Noise 0.1Hz to 10Hz, LT1236-5, C = 0 LT1236-5, C = 1000pF LT1236-5 LOAD LOAD (cid:13) ISOURCE = 0 ISINK = 0 FILTERING = 1 ZERO AT 0.1Hz(cid:13) E (50mV/DIV) ISOURCE 5=0 0mV ISINK5 =0 m0V E (20mV/DIV) 20mV 20mV µNOISE (5V/DIV)(cid:13)(cid:13)(cid:13) 5m V (1pp2m P)OLES AT 10Hz CHANG ISOURCE = 0.5mA ISINK = 0.2mA CHANG ISOURCE = 0.2mA ISINK = 0.2mA (cid:13) LTAGE (cid:13) TPUT ISOURCE = 2-10mA ISINK = 2-10mA TPUT ISINK = 2-10mA UT VO(cid:13) U U P O O T ISOURCE = 2-10mA OU(cid:13) D ISOURCE = 100m AP-P D ISINK = 100m AP-P D ISOURCE = 100m AP-P D ISINK = 100m AP-P (cid:13) (cid:13) 0 1 2 3 4 0 1 2 3 4 (cid:13) 0 5 10 15 20 0 5 10 15 20 0 1 2 3 4 5 6 TIME (m s) TIME (m s) TIME (MINUTES) LT1236 G13 LT1236 G14 LT1236 G15 5

LT1236 TYPICAL PERFORWAUCE CHARACTERISTICS Output Voltage Temperature Drift, LT1236-10 Load Regulation, LT1236-10 Input Supply Current, LT1236-10 10.0020 5 1.8 10.0015 4 VIN = 12V 1.6 IOUT = 0 TJ = –55°C 3 OUTPUT VOLTAGE (V)11100099.....00099000991009905050 OUTPUT CHANGE (mV) –––320211 INPUT CURRENT (mA) 010110......804246 TTJJ = = 1 2255°°CC 9.9985 –4 0.2 9.9980 –5 0 –40 –20 0 20 40 60 80 100 –10 –8 –6 –4 –2 0 2 4 6 8 10 0 5 10 15 20 25 30 35 40 TEMPERATURE (˚C) SOURCING SINKING INPUT VOLTAGE (V) LT1236 G16 OUTPUT CURRENT (mA) LT1236 G17 LT1236 G18 Shunt Mode Current Limit, Shunt Characteristics, LT1236-10 LT1236-10 Thermal Regulation, LT1236-10 1.8 60 (cid:13) INPUT PIN OPEN INPUT PIN OPEN VIN = 30V(cid:13) 1.6 (cid:13) D POWER = 200mW 50 A) 1.4 A) LOAD(cid:13) PUT (m 1.2 PUT (m 40 E (mV) –0.50 REGULATION OUT 1.0 TJ = –55°C OUT ANG NTO 0.8 NTO 30 T CH –1.0 TRHEEGRUMLAATLI O(cid:13) N* ENT I 0.6 TJ = 25°C ENT I 20 UTPU –1.5 CURR 0.4 TJ = 125°C CURR 10 O (cid:13) ILOAD = 10mA 0.2 (cid:13) 0 0 (cid:13) 0 2 4 6 8 10 12 0 2 4 6 8 10 12 14 16 18 (cid:13) 0 20 40 60 80 100 120 140 OUTPUT TO GROUND VOLTAGE (V) OUTPUT VOLTAGE (V) TIME (ms) LT1236 G19 LT1236 G20 *INDEPENDENT OF TEMPERATURE COEFFICIENT LT1236 G21 Load Transient Response, Load Transient Response, Output Noise 0.1Hz to 10Hz, LT1236-10, C = 0 LT1236-10, C = 1000pF LT1236-10 LOAD LOAD (cid:13) ISINK = 0.6mA ISINK = 0.8mA FILTERING = 1 ZERO AT 0.1Hz(cid:13) ISOURCE = 0 ISOURCE = 0 DIV)(cid:13) 2 POLES AT 10Hz AGE CHANGE 10mV 5IS0ImNKV = 0.8mA AGE CHANGE 5mV ISINK = 1.2mA20mV µNOISE (10V/(cid:13)(cid:13) 10m V (1ppm) UTPUT VOLT ISOURCE = 0.2mA ISINK = 1.0mA UTPUT VOLT ISOURCE = 0.5mA ISINK = 1.4mA UT VOLTAGE (cid:13)(cid:13) O O P ISOURCE = 2-10mA ISINK = 2-10mA ISOURCE = 2-10mA ISINK = 2-10mA OUT(cid:13) D ISOURCE = 100m AP-P D ISINK = 100m AP-P D ISOURCE = 100m AP-P D ISINK = 100m AP-P (cid:13) (cid:13) 0 1 2 3 4 0 1 2 3 4 (cid:13) 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 5 6 TIME (m s) TIME (m s) TIME (MINUTES) NOTE VERTICAL SCALE CHANGE(cid:13) NOTE VERTICAL SCALE CHANGE(cid:13) LT1236 G24 BETWEEN SOURCING AND SINKING BETWEEN SOURCING AND SINKING LT1236 G22 LT1236 G23 6

LT1236 APPLICATIOUNS INUFORWMATIOUN Effect of Reference Drift on System Accuracy in series with a 20kW potentiometer will give – 10mV trim range. Effect on the output TC will be only 1ppm/(cid:176) C for the A large portion of the temperature drift error budget in – 5mV trim needed to set the “A” device to 10.000V. many systems is the system reference voltage. This graph indicates the maximum temperature coefficient allowable LT1236-5 if the reference is to contribute no more than 0.5LSB error to the overall system performance. The example shown is The LT1236-5 does have an output voltage trim pin, but a 12-bit system designed to operate over a temperature the TC of the nominal 4V open circuit voltage at pin 5 is range from 25(cid:176) C to 65(cid:176) C. Assuming the system calibra- about –1.7mV/(cid:176) C. For the voltage trimming not to affect tion is performed at 25(cid:176) C, the temperature span is 40(cid:176) C. reference output TC, the external trim voltage must track It can be seen from the graph that the temperature coeffi- the voltage on the trim pin. Input impedance of the trim pin cient of the reference must be no worse than 3ppm/(cid:176) C if is about 100kW and attenuation to the output is 13:1. The it is to contribute less than 0.5LBS error. For this reason, technique shown below is suggested for trimming the the LT1236 family has been optimized for low drift. output of the LT1236-5 while maintaining minimum shift in output temperature coefficient. The R1/R2 ratio is Maximum Allowable Reference Drift chosen to minimize interaction of trimming and TC shifts, 100 so the exact values shown should be used. R (cid:13) O F NT 8-BIT EFFICIE°m/C) LT12(cid:13)36-5 RE COR (pp 10-BIT IN OUT VOUT UO 10 GND TRIM R1(cid:13) TR AR 27k M TEMPER0.5LSB E 12-BIT 1N4148 R502k(cid:13) U 14-BIT M XI A M 1.0 LT1236 AI02 (cid:13) 10 20 30 40 50 60 70 80 90 100 TEMPERATURE SPAN (°C) Capacitive Loading and Transient Response LT1236 AI01 The LT1236 is stable with all capacitive loads, but for Trimming Output Voltage optimum settling with load transients, output capacitance The LT1236-10 has a trim pin for adjusting output voltage. should be under 1000pF. The output stage of the reference The impedance of the trim pin is about 12kW with a is class AB with a fairly low idling current. This makes nominal open circuit voltage of 5V. It is designed to be transient response worse-case at light load currents. driven from a source impedance of 3kW or less to mini- Because of internal current drain on the output, actual mize changes in the LT1236 TC with output trimming. worst-case occurs at I = 0 on LT1236-5 and I = LOAD LOAD Attenuation between the trim pin and the output is 70:1. 1.4mA (sinking) on LT1236-10. Significantly better load This allows – 70mV trim range when the trim pin is tied to transient response is obtained by moving slightly away the wiper of a potentiometer connected between the from these points. See Load Transient Response curves output and ground. A 10kW potentiometer is recom- for details. In general, best transient response is obtained mended, preferably a 20 turn cermet type with stable when the output is sourcing current. In critical applica- characteristics over time and temperature. tions, a 10m F 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 APPLICATIOUNS INUFORWMATIOUN Kelvin Connections temperature gradients in the package leads. Variations in thermal resistance, caused by uneven air flow, create Although the LT1236 does not have true force/sense differential lead temperatures, thereby causing thermo- capability at its outputs, significant improvements in ground electric voltage noise at the output of the reference. 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 Standard Series Mode (cid:13) line, greatly reducing ground loop and loss problems on (cid:13) the low side of the reference. The high side supplies load LT1236 KEEP THIS LINE RESISTANCE LOW current so line resistance must be kept low. Twelve feet of INPUT IN OUT + #22 gauge hook-up wire or 1 foot of 0.025 inch printed GND LOAD circuit trace will create 2mV loss at 10mA output current. This is equivalent to 1LSB in a 10V, 12-bit system. GROUND(cid:13) RETURN The following circuits show proper hook-up to minimize LT1236 AI03 errors due to ground loops and line losses. Losses in the output lead can be greatly reduced by adding a PNP boost Series Mode with Boost Transistor transistor if load currents are 5mA or higher. R2 can be INPUT added to further reduce current in the output sense lead. R1(cid:13) 220W 2N3906 Effects of Air Movement on Low Frequency Noise The LT1236 has very low noise because of the buried zener IN used in its design. In the 0.1Hz to 10Hz band, peak-to-peak LT1236 noise is about 0.5ppm of the DC output. To achieve this OUT GND LOAD low noise, however, care must be taken to shield the R2* reference from ambient air turbulence. Air movement can create noise because of thermoelectric differences be- GROUND(cid:13) RETURN tween IC package leads and printed circuit board materials and/or sockets. Power dissipation in the reference, even *OPTIONAL—REDUCES CURRENT IN OUTPUT SENSE (cid:13) LEAD: R2 = 2.4k (LT1236-5), 5.6k (LT1236-10) though it rarely exceeds 20mW, is enough to cause small LT1236 AI04 TYPICAL APPLICATIONUS Restricted Trim Range for Improved LT1236-10 Full Trim Range (– 0.7%) Negative Series Reference Resolution, 10V, “A” Version Only 15V LT1236-10 (cid:13) R1(cid:13) LT1236A-10 LT1236-10 VIN IN OUT VOUT 4.7k VIN IN OUT 10.000V GND TRIM IN OUT GND TRIM 7R51k(cid:13) R2(cid:13) R101k*(cid:13) 4R.72k(cid:13) D151V(cid:13) GND 50k –10V AT(cid:13) –15V Q1(cid:13) 50mA LT1236 TA03 2N2905 LT1236 TA04 TRIM RANGE » – 10mV LT1236 TA10 *CAN BE RAISED TO 20k FOR LESS(cid:13) CRITICAL APPLICATIONS 8

LT1236 TYPICAL APPLICATIONUS Boosted Output Current Boosted Output Current with No Current Limit with Current Limit – 10V Output Reference V+ ‡ (VOUT + 1.8V) V+ ‡ VOUT + 2.8V R2210(cid:13)W DLE1D*(cid:13) R2210(cid:13)W 8.2W LT1236-10 15V VIN VOUT +10V 2N2905 2N2905 GND IN LT1236 IN COM 10V AT(cid:13) LT1236 (cid:13) OUT 100mA 10V AT(cid:13) LT1236-10 GND + 2m F(cid:13) (cid:13) OUT 100mA SOLID(cid:13) GND + 2m F(cid:13) VIN VOUT TANT SOLID(cid:13) TANT GND –10V LT1236 TA05 *GLOWS IN CURRENT LIMIT,(cid:13) R1= –15V –10V R1 ILOAD DO NOT OMIT LT1236 TA06 ILOAD+ 1.5mA –15V LT1236 TA17 Handling Higher Load Currents Operating 5V Reference from 5V Supply 15V 30mA 5V LOGIC(cid:13) SUPPLY 1N914 (cid:13) IN R1*(cid:13) CMOS LOGIC GATE** LT1236-5 LT1236-O10UT 169W 1V0OVUT(cid:13) fIN ‡ 2kHz* C1*+(cid:13) 1N914 +»C28*.5(cid:13)V IN GNDOUT 5RVE(cid:13)FERENCE GND 5m F 5m F RL TCYUPRIRCEANLT L =O A3D0m(cid:13) A *F(cid:13) OR HIGHER FREQUENCIES C1 AND C2 MAY BE DECREASED(cid:13) **PARALLEL GATES FOR HIGHER REFERENCE CURRENT LOADING LT1236 TA15 *SELECT R1 TO DELIVER TYPICAL LOAD CURRENT.(cid:13) LT1236 WILL THEN SOURCE OR SINK AS NECESSARY(cid:13) TO MAINTAIN PROPER OUTPUT. DO NOT REMOVE LOAD (cid:13) AS OUTPUT WILL BE DRIVEN UNREGULATED HIGH. LINE(cid:13) 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(cid:13) OU(cid:13)T 4.02K(cid:13) VIN IN OUT VOUT = 10.24V LT1236-10 1% R4*(cid:13) TRIM GND 100W (cid:13) TRIM FB FULL-SCALE(cid:13) GND R1(cid:13) CMOS(cid:13) 30pF ADJUST 4.99k(cid:13) DAC(cid:13) IOUT – 4.32k 1% LTC7543 REF LT1007C 10V(cid:13) F.S. 5k R2(cid:13) + 40.2W (cid:13) 1% V– = –15V* 1.2k *T(cid:13) C LESS THAN 200ppm/°C(cid:13) *MUST BE WELL REGULATED –15V **NWOIT ZHE RLTO1 A00D7J U(VS0TS R £E 6Q0UmIRVE)D(cid:13) LT1236 TA14 dVdOVU–T=15VmV LT1236 TA11 9

LT1236 TYPICAL APPLICATIONUS Strain Gauge Conditioner for 350W Bridge Negative Shunt Reference Driven by Current Source R1(cid:13) 357W (cid:13) 1/2W (cid:13) LT1236-10 (cid:13) 28mA OUT LT1236-10 28.5mA GND 15V IN OUT 5V GND 350W STRAIN(cid:13) R3(cid:13) –10V (ILOAD £ 1mA) GAUGE BRIDGE** 2M 2.5mA R2(cid:13) + 3 20k 2 – LM334 6 LM301A† R4(cid:13) LT1012C 6 VOUT(cid:13) 2 20k 3 X100 1 – + 100pF 8 R5(cid:13) 27W 2M R6*(cid:13) 2M –5V –11V TO –40V LT1236 TA13 357W (cid:13) 1/2W –15V *THIS RESISTOR PROVIDES POSITIVE FEEDBACK TO (cid:13) **B(cid:13) RIDGE IS ULTRA-LINEAR WHEN ALL LEGS ARE(cid:13) THE BRIDGE TO ELIMINATE LOADING EFFECT OF (cid:13) A(cid:13) CTIVE, TWO IN COMPRESSION AND TWO IN TENSION,(cid:13) THE AMPLIFIER. EFFECTIVE ZIN OF AMPLIFIER (cid:13) O(cid:13) R WHEN ONE SIDE IS ACTIVE WITH ONE COMPRESSED(cid:13) STAGE IS ‡ 1MW . IF R2 TO R5 ARE CHANGED,(cid:13) A(cid:13) ND ONE TENSIONED LEG(cid:13) SET R6 = R3 †OFFSET AND DRIFT OF LM301A ARE VIRTUALLY(cid:13) ELIMINATED BY DIFFERENTIAL CONNECTION OF LT1012C LT1236 TA08 Precision DAC Reference with System TC Trim 2-Pole Lowpass Filtered Reference 1m F(cid:13) LT1236-10 MYLAR(cid:13) VIN (cid:13) (cid:13) 15V IN OUT (cid:13) – GND 8.87k(cid:13) LT1236 LT1001 VREF 1% VIN IN OUT + R1(cid:13) R2(cid:13) 50k(cid:13) GND D1N1(cid:13)457 10k(cid:13) RTROIOMM TEMP(cid:13) 36kf = 10Hz36k 0M.5YmLFA(cid:13)R(cid:13) T£ O2Tm AVLR MNSO(cid:13)ISE (cid:13) 50k (cid:13) 1% 10.36k(cid:13) (cid:13) 1Hz £ f £ 10kHz 1.24k(cid:13) TC TRIM* 1% 1% 10k(cid:13) D2(cid:13) 200k(cid:13) 1% 1N457 1% –VREF LT1236 TA12 50k 1mA 8.45k *TRIMS 1mA REFERENCE CURRENT (cid:13) TC BY – 40ppm/°C. THIS TRIM (cid:13) DAC SCHEME HAS VERY LITTLE EFFECT ON ROOM(cid:13) TEMPERATURE CURRENT TO MINIMIZE ITERATIVE(cid:13) TRIMMING LT1236 TA16 10

LT1236 TYPICAL APPLICATIONUS Ultra-Linear Platinum Temperature Sensor* (cid:13) LT1236-10 OUT IN 20V GND R2*(cid:13) R10(cid:13) 5k 182k(cid:13) 1% R1**(cid:13) R14(cid:13) 253k 5k R11(cid:13) 6.65M(cid:13) R15(cid:13) 1% 10k R8(cid:13) Rf**(cid:13) 10M 654k R9(cid:13) R12(cid:13) 100k 1k R13(cid:13) 20V 24.3k R5(cid:13) 2 – 7 R5k3**(cid:13) 41.R7%45(cid:13)k(cid:13) 210%0k(cid:13) 3 +LT1001 6 –V5O0U°TC = ≤1 0T0 ≤m 1V5/°0C°(cid:13)C 4 RS†(cid:13) 100W AT(cid:13) R6(cid:13) –15V 0°C 619k(cid:13) †(cid:13)STANDARD INDUSTRIAL 100W PLATINUM 4-WIRE SENSOR,(cid:13) 1% (cid:13)ROSEMOUNT 78S OR EQUIVALENT. a = 0.00385(cid:13) R319%72(cid:13)k(cid:13) (cid:13)(cid:13)(cid:13)(cid:13)TTTRRRIIIMMM RRR11924 F OFFOORRR V VVOOOUUUT TT= == 0 15V0V AV AT AT 0T 5° C10(cid:13)0°C0(cid:13)°C(cid:13) –15V (cid:13)USE TRIM SEQUENCE AS SHOWN. TRIMS ARE NONINTERACTIVE (cid:13) SO THAT ONLY ONE TRIM SEQUENCE IS NORMALLY REQUIRED.(cid:13) *(cid:13)FEEDBACK LINEARIZES OUTPUT TO – 0.005°C FROM(cid:13) (cid:13)–50°C TO 150°C(cid:13) LT1236 TA09 **WIREWOUND RESISTORS WITH LOW TC EQUIVALEU (cid:13)T SCHEW A(cid:13) TIC INPUT Q3 D1 D2 OUTPUT D3 R1 Q1 – + A1 R2 D4(cid:13) 6.3V Q2 GND LT1236 ES Information furnished by Linear Technology Corporation is believed to be accurate and reliable. 11 However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

LT1236 PACKAGE DESCRIPTIOUN Dimensions in inches (millimeters) unless otherwise noted. N8 Package 8-Lead Plastic DIP 0.400*(cid:13) (10.160)(cid:13) 0.300 – 0.325(cid:13) 0.045 – 0.065(cid:13) 0.130 – 0.005(cid:13) MAX (7.620 – 8.255) (1.143 – 1.651) (3.302 – 0.127) 8 7 6 5 0.065(cid:13) 0.255 – 0.015*(cid:13) (1.651)(cid:13) 0.009 – 0.015(cid:13) TYP (6.477 – 0.381)(cid:13) (0.229 – 0.381) 0.125(cid:13) (cid:13) (3.175)(cid:13) 0.015(cid:13) 0.325+0.025(cid:13) 0.045 – 0.015(cid:13) MIN(cid:13) (0.380)(cid:13) 1 2 3 4 ( –0.015) (1.143 – 0.381) (cid:13) MIN +0.635(cid:13) 8.255–0.381 0.100 – 0.010(cid:13) 0.018 – 0.003(cid:13) (2.540 – 0.254) (0.457 – 0.076) N8 0395 *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.(cid:13) MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm). S8 Package 8-Lead Plastic SOIC 0.189 – 0.197*(cid:13) (4.801 – 5.004) 0.010 – 0.020(cid:13) · 45(cid:176) 0.053 – 0.069(cid:13) 0.004 – 0.010(cid:13) 8 7 6 5 (0.254 – 0.508) (1.346 – 1.752) (0.101 – 0.254) 0.008 – 0.010(cid:13) (0.203 – 0.254) 0°– 8° TYP 0.228 – 0.244(cid:13) 0.150 – 0.157*(cid:13) 0.016 – 0.050(cid:13) (5.791 – 6.197) (3.810 – 3.988) 0.014 – 0.019(cid:13) 0.050(cid:13) 0.406 – 1.270 (0.355 – 0.483) (1.270)(cid:13) BSC *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.(cid:13) MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm). 1 2 3 4 SO8 0294 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1019 Precision Bandgap Reference 0.05%, 5ppm/(cid:176) C LT1027 Precision 5V Reference 0.02%, 2ppm/(cid:176) C 12 Linear Technology Corporation LT/GP 0695 10K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7487 (408) 432-1900 l F AX: (408) 434-0507 l TELEX: 499-3977 ª LINEAR TECHNOLOGY CORPORATION 1995

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