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 low-temperature-coefficient 2.5V zener with 0.2 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 LM136-2.5 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 -55C to +125C while the LM236-2.5 is rated over a -25C to +85C temperature range. The LM336-2.5 is rated for operation over a 0C to +70C temperature range. See the connection diagrams for available packages. Features Low temperature coefficient Wide operating current of 400 A to 10 mA 0.2 dynamic impedance 1% initial tolerance available Guaranteed temperature stability Easily trimmed for minimum temperature drift Fast turn-on Connection Diagrams TO-92 Plastic Package SO Package 571508 Bottom View Order Number LM336Z-2.5 or LM336BZ-2.5 See NS Package Number Z03A 571512 Top View Order Number LM236M-2.5, LM236AM-2.5, LM336M-2.5 or LM336BM-2.5 See NS Package Number M08A TO-46 Metal Can Package 571520 Bottom View Order Number LM136H-2.5, LM136H-2.5/883, LM236H-2.5, or LM236AH-2.5 See NS Package Number H03H (c) 2009 National Semiconductor Corporation 5715 www.national.com LM136-2.5/LM236-2.5/LM336-2.5V Reference Diode February 27, 2009 LM136-2.5 LM236-2.5 LM336-2.5V LM136-2.5/LM236-2.5/LM336-2.5V Typical Applications 2.5V Reference 571509 2.5V Reference with Minimum Temperature Coefficient 571510 Adjust to 2.490V *Any silicon signal diode Wide Input Range Reference 571511 www.national.com 2 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 10 mA Storage Temperature -60C to +150C Operating Temperature Range (Note 2) LM136 -55C to +150C LM236 -25C to +85C Electrical Characteristics Parameter Reverse Breakdown Voltage (Note 3) LM136A-2.5/LM236A-2.5 LM136-2.5/LM236-2.5 Conditions LM336B-2.5 LM336-2.5 Units Min Typ Max Min Typ Max 2.440 2.465 2.490 2.490 2.540 2.515 2.390 2.440 2.490 2.490 2.590 2.540 V V 2.6 6 2.6 10 mV 0.2 0.6 0.2 1 1.8 6 mV TA=25C, IR=1 mA LM136, LM236, LM336 LM136A, LM236A, LM336B Reverse Breakdown Change With Current TA=25C, Reverse Dynamic Impedance TA=25C, IR=1 mA, f = 100 Hz 400 AIR10 mA Temperature Stability VR Adjusted to 2.490V (Note 4) IR=1 mA, Figure 2 0CTA70C (LM336) -25CTA+85C 3.5 9 mV -25C TA +85C (LM236M) 7.5 18 mV -55CTA+125C (LM136) 12 18 mV Reverse Breakdown Change With Current 400 AIR10 mA 3 10 3 12 mV Reverse Dynamic Impedance IR=1 mA 0.4 1 0.4 1.4 Long Term Stability TA=25C 0.1C, IR=1 mA, 20 (LM236H, LM236Z) 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 LM236 LM336 150C 125C 100C Thermal Resistance ja (Junction to Ambient) TO-92 180C/W (0.4 leads) TO-46 SO-8 440C/W 165C/W 170C/W (0.125 lead) ja (Junction to Case) n/a 3 80C/W n/a www.national.com LM136-2.5/LM236-2.5/LM336-2.5V LM336 0C to +70C Soldering Information TO-92 Package (10 sec.) 260C TO-46 Package (10 sec.) 300C SO Package Vapor Phase (60 sec.) 215C Infrared (15 sec.) 220C See AN-450 "Surface Mounting Methods and Their Effect on Product Reliability" (Appendix D) for other methods of soldering surface mount devices. Absolute Maximum Ratings (Note 1) LM136-2.5/LM236-2.5/LM336-2.5V Note 3: Unless otherwise specified, the LM136-2.5 is specified from -55C TA +125C, the LM236-2.5 from -25C TA +85C and the LM336-2.5 from 0C TA +70C. 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 25C 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 571522 571521 Dynamic Impedance Response Time 571524 571523 Reverse Characteristics Forward Characteristics 571525 571526 5 www.national.com LM136-2.5/LM236-2.5/LM336-2.5V Temperature Drift 571528 FIGURE 1. LM136 With Pot for Adjustment of Breakdown Voltage (Trim Range = 120 mV typical) 571527 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. 571529 FIGURE 2. Temperature Coefficient Adjustment (Trim Range = 70 mV typical) Low Cost 2 Amp Switching Regulator 571505 *L1 60 turns #16 wire on Arnold Core A-254168-2 Efficiency 80% www.national.com 6 LM136-2.5/LM236-2.5/LM336-2.5V Precision Power Regulator with Low Temperature Coefficient 571513 5V Crowbar Trimmed 2.5V Reference with Temperature Coefficient Independent of Breakdown Voltage 571515 *Does not affect temperature coefficient 571514 Adjustable Shunt Regulator 571506 7 www.national.com LM136-2.5/LM236-2.5/LM336-2.5V Linear Ohmmeter 571516 Op Amp with Output Clamped Bipolar Output Reference 571517 571518 www.national.com 8 LM136-2.5/LM236-2.5/LM336-2.5V 2.5V Square Wave Calibrator 571519 5V Buffered Reference 571530 Low Noise Buffered Reference 571531 9 www.national.com LM136-2.5/LM236-2.5/LM336-2.5V Schematic Diagram 571501 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 TO-92 Plastic Package (Z) Order Number LM336Z-2.5 or LM336BZ-2.5 NS Package Number Z03A www.national.com 12 www.national.com 13 LM136-2.5/LM236-2.5/LM336-2.5V Notes LM136-2.5/LM236-2.5/LM336-2.5V Reference Diode Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Design Support Amplifiers www.national.com/amplifiers WEBENCH(R) Tools www.national.com/webench Audio www.national.com/audio App Notes www.national.com/appnotes Clock and Timing www.national.com/timing Reference Designs www.national.com/refdesigns Data Converters www.national.com/adc Samples www.national.com/samples Interface www.national.com/interface Eval Boards www.national.com/evalboards LVDS www.national.com/lvds Packaging www.national.com/packaging Power Management www.national.com/power Green Compliance www.national.com/quality/green Switching Regulators www.national.com/switchers Distributors www.national.com/contacts LDOs www.national.com/ldo Quality and Reliability www.national.com/quality LED Lighting www.national.com/led Feedback/Support www.national.com/feedback Voltage Reference www.national.com/vref Design Made Easy www.national.com/easy PowerWise(R) Solutions www.national.com/powerwise Solutions www.national.com/solutions Serial Digital Interface (SDI) www.national.com/sdi Mil/Aero www.national.com/milaero Temperature Sensors www.national.com/tempsensors SolarMagicTM www.national.com/solarmagic Wireless (PLL/VCO) www.national.com/wireless Analog University(R) www.national.com/AU THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION ("NATIONAL") PRODUCTS. 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