LM136-2.5/LM236-2.5/LM336-2.5V Reference Diode General Description The LM136-2.5/LM236-2.5 and LM336-2.5 integrated circuits are precision 2.5V shunt regulator diodes. These monolithic IC voltage references operate as a lowtemperature-coefficient 2.5V zener with 0.2Ω dynamic impedance. A third terminal on the LM136-2.5 allows the reference voltage and temperature coefficient to be trimmed easily. The LM136-2.5 series is useful as a precision 2.5V low voltage reference for digital voltmeters, power supplies or op amp circuitry. The 2.5V make it convenient to obtain a stable reference from 5V logic supplies. Further, since the LM1362.5 operates as a shunt regulator, it can be used as either a positive or negative voltage reference. The LM136-2.5 is rated for operation over −55˚C to +125˚C while the LM236-2.5 is rated over a −25˚C to +85˚C temperature range. The LM336-2.5 is rated for operation over a 0˚C to +70˚C temperature range. See the connection diagrams for available packages. Features n n n n n n n Low temperature coefficient Wide operating current of 400 µA to 10 mA 0.2Ω dynamic impedance ± 1% initial tolerance available Guaranteed temperature stability Easily trimmed for minimum temperature drift Fast turn-on Connection Diagrams SO Package TO-92 Plastic Package 00571508 Bottom View Order Number LM336Z-2.5 or LM336BZ-2.5 See NS Package Number Z03A 00571512 TO-46 Metal Can Package Top View Order Number LM236M-2.5, LM236AM-2.5, LM336M-2.5 or LM336BM-2.5 See NS Package Number M08A 00571520 Bottom View Order Number LM136H-2.5, LM136H-2.5/883, LM236H-2.5, or LM236AH-2.5 See NS Package Number H03H © 2005 National Semiconductor Corporation DS005715 www.national.com LM136-2.5/LM236-2.5/LM336-2.5V Reference Diode June 2005 LM136-2.5/LM236-2.5/LM336-2.5V Typical Applications Wide Input Range Reference 2.5V Reference 00571509 2.5V Reference with Minimum Temperature Coefficient 00571511 00571510 † Adjust to 2.490V * Any silicon signal diode www.national.com 2 LM336 Soldering Information If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Reverse Current 15 mA Forward Current TO-92 Package (10 sec.) 260˚C TO-46 Package (10 sec.) 300˚C SO Package 10 mA Storage Temperature −60˚C to +150˚C Operating Temperature Range (Note 2) LM136 −55˚C to +150˚C LM236 −25˚C to +85˚C 0˚C to +70˚C Vapor Phase (60 sec.) 215˚C Infrared (15 sec.) 220˚C See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” (Appendix D) for other methods of soldering surface mount devices. Electrical Characteristics (Note 3) Parameter Conditions LM136A-2.5/LM236A-2.5 LM336B-2.5 LM136-2.5/LM236-2.5 LM336-2.5 Min Reverse Breakdown Voltage Typ Max Min Typ Units Max TA=25˚C, IR=1 mA LM136, LM236, LM336 2.440 2.490 2.540 2.390 2.490 2.590 V LM136A, LM236A, LM336B 2.465 2.490 2.515 2.440 2.490 2.540 V Reverse Breakdown Change TA=25˚C, 2.6 6 2.6 10 mV 0.2 0.6 0.2 1 Ω 1.8 6 mV 3.5 9 mV −25˚C ≤ TA ≤ +85˚C (LM236M) 7.5 18 mV −55˚C≤TA≤+125˚C (LM136) 12 18 mV 400 µA≤IR≤10 mA 3 10 3 12 mV 1 0.4 1.4 Ω With Current 400 µA≤IR≤10 mA Reverse Dynamic Impedance TA=25˚C, IR=1 mA, f = 100 Hz Temperature Stability VR Adjusted to 2.490V (Note 4) IR=1 mA, Figure 2 0˚C≤TA≤70˚C (LM336) −25˚C≤TA≤+85˚C (LM236H, LM236Z) Reverse Breakdown Change With Current Reverse Dynamic Impedance IR=1 mA 0.4 Long Term Stability TA=25˚C ± 0.1˚C, IR=1 mA, 20 20 ppm t = 1000 hrs Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Electrical specifications do not apply when operating the device beyond its specified operating conditions. Note 2: For elevated temperature operation, Tj max is: LM136 150˚C LM236 125˚C LM336 100˚C Thermal Resistance θja (Junction to Ambient) TO-92 TO-46 SO-8 180˚C/W (0.4" leads) 440˚C/W 165˚C/W 80˚C/W n/a 170˚C/W (0.125" lead) θja (Junction to Case) n/a 3 www.national.com LM136-2.5/LM236-2.5/LM336-2.5V Absolute Maximum Ratings (Note 1) LM136-2.5/LM236-2.5/LM336-2.5V Electrical Characteristics (Note 3) (Continued) Note 3: Unless otherwise specified, the LM136-2.5 is specified from −55˚C ≤ TA ≤ +125˚C, the LM236-2.5 from −25˚C ≤ TA ≤ +85˚C and the LM336-2.5 from 0˚C ≤ TA ≤ +70˚C. Note 4: Temperature stability for the LM336 and LM236 family is guaranteed by design. Design limits are guaranteed (but not 100% production tested) over the indicated temperature and supply voltage ranges. These limits are not used to calculate outgoing quality levels. Stability is defined as the maximum change in Vref from 25˚C to TA (min) or TA (max). www.national.com 4 LM136-2.5/LM236-2.5/LM336-2.5V Typical Performance Characteristics Reverse Voltage Change Zener Noise Voltage 00571522 00571521 Dynamic Impedance Response Time 00571524 00571523 Reverse Characteristics Forward Characteristics 00571525 00571526 5 www.national.com LM136-2.5/LM236-2.5/LM336-2.5V Typical Performance Characteristics (Continued) Temperature Drift 00571528 FIGURE 1. LM136 With Pot for Adjustment of Breakdown Voltage (Trim Range = ± 120 mV typical) 00571527 Application Hints The LM136 series voltage references are much easier to use than ordinary zener diodes. Their low impedance and wide operating current range simplify biasing in almost any circuit. Further, either the breakdown voltage or the temperature coefficient can be adjusted to optimize circuit performance. Figure 1 shows an LM136 with a 10k potentiometer for adjusting the reverse breakdown voltage. With the addition of R1 the breakdown voltage can be adjusted without affecting the temperature coefficient of the device. The adjustment range is usually sufficient to adjust for both the initial device tolerance and inaccuracies in buffer circuitry. If minimum temperature coefficient is desired, two diodes can be added in series with the adjustment potentiometer as shown in Figure 2. When the device is adjusted to 2.490V the temperature coefficient is minimized. Almost any silicon signal diode can be used for this purpose such as a 1N914, 1N4148 or a 1N457. For proper temperature compensation the diodes should be in the same thermal environment as the LM136. It is usually sufficient to mount the diodes near the LM136 on the printed circuit board. The absolute resistance of R1 is not critical and any value from 2k to 20k will work. www.national.com 00571529 FIGURE 2. Temperature Coefficient Adjustment (Trim Range = ± 70 mV typical) 6 LM136-2.5/LM236-2.5/LM336-2.5V Application Hints (Continued) Low Cost 2 Amp Switching Regulator† 00571505 *L1 † 60 turns #16 wire on Arnold Core A-254168-2 Efficiency ≈ 80% Precision Power Regulator with Low Temperature Coefficient 00571513 5V Crowbar Trimmed 2.5V Reference with Temperature Coefficient Independent of Breakdown Voltage 00571515 *Does not affect temperature coefficient 00571514 7 www.national.com LM136-2.5/LM236-2.5/LM336-2.5V Application Hints (Continued) Adjustable Shunt Regulator 00571506 Linear Ohmmeter 00571516 www.national.com 8 (Continued) LM136-2.5/LM236-2.5/LM336-2.5V Application Hints 2.5V Square Wave Calibrator Op Amp with Output Clamped 00571519 5V Buffered Reference 00571517 Bipolar Output Reference 00571530 Low Noise Buffered Reference 00571531 00571518 9 www.national.com LM136-2.5/LM236-2.5/LM336-2.5V Schematic Diagram 00571501 www.national.com 10 LM136-2.5/LM236-2.5/LM336-2.5V Physical Dimensions inches (millimeters) unless otherwise noted Order Number LM136H-2.5, LM136H-2.5/883, LM236H-2.5, LM136AH-2.5, LM136AH-2.5/883 or LM236AH-2.5 NS Package Number H03H Small Outline (SO) Package (M) Order Number LM236M-2.5, LM236AM-2.5, LM336M-2.5 or LM336BM-2.5 NS Package Number M08A 11 www.national.com LM136-2.5/LM236-2.5/LM336-2.5V Reference Diode Physical Dimensions inches (millimeters) unless otherwise noted (Continued) TO-92 Plastic Package (Z) Order Number LM336Z-2.5 or LM336BZ-2.5 NS Package Number Z03A National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. 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