LM329 Precision Reference General Description The LM329 is a precision multi-current temperature-compensated 6.9V zener reference with dynamic impedance a factor of 10 to 100 less than discrete diodes. Constructed in a single silicon chip, the LM329 uses active circuitry to buffer the internal zener allowing the device to operate over a 0.5 mA to 15 mA range with virtually no change in performance. The LM329 is available with a temperature coefficients of 0.01%/ °C. This reference also has excellent long term stability and low noise. A new subsurface breakdown zener used in the LM329 gives lower noise and better long-term stability than conventional IC zeners. Further the zener and temperature compensating transistor are made by a planar process so they are immune to problems that plague ordinary zeners. For example, there is virtually no voltage shift in zener voltage due to temperature cycling and the device is insensitive to stress on the leads. The LM329 can be used in place of conventional zeners with improved performance. The low dynamic impedance simpli- Connection Diagram fies biasing and the wide operating current allows the replacement of many zener types. The LM329 for operation over 0°C to 70°C is available in a TO-92 epoxy package. Features ■ ■ ■ ■ ■ ■ ■ ■ 0.6 mA to 15 mA operating current 0.8Ω dynamic impedance at any current Available with temperature coefficient of 0.01%/°C 7μV wideband noise 5% initial tolerance 0.002% long term stability Low cost Subsurface zener Typical Applications Plastic Package (TO-92) Simple Reference 571404 Bottom View Order Number LM329DZ See NS Package Z03A © 2008 National Semiconductor Corporation 5714 571401 www.national.com LM329 Precision Reference January 17, 2008 LM329 Operating Temperature Range LM329 Storage Temperature Range Soldering Information TO-92 package: 10 sec. Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Reverse Breakdown Current Forward Current Electrical Characteristics (Note 2) Conditions with Current (Note 3) Reverse Dynamic Impedance Min Typ Max Units TA = 25°C, 0.6 mA ≤ IR ≤ 15 mA Reverse Breakdown Change 260°C 30 mA 2 mA Parameter Reverse Breakdown Voltage 0°C to +70°C −55°C to +150°C 6.6 6.9 7.25 V 0.6 mA ≤ IR ≤ 15 mA 9 20 mV TA = 25°C, IR = 1 mA 0.8 2 Ω 7 100 μV TA = 25°C, (Note 3) RMS Noise TA = 25°C, 10 Hz ≤ F ≤ 10 kHz Long Term Stability TA = 45°C ± 0.1°C, (1000 hours) IR = 1 mA ± 0.3% 20 Temperature Coefficient IR = 1 mA 50 Change In Reverse Breakdown 1 mA ≤ IR ≤ 15 mA 1 ppm/°C 1 mA ≤ IR ≤ 15 mA 12 mV 1 mA ≤ IR ≤ 15 mA 1 Ω ppm 100 ppm/°C Temperature Coefficient Reverse Breakdown Change with Current Reverse Dynamic Impedance Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. Note 2: These specifications apply for 0°C ≤ TA ≤ +70°C for the LM329 unless otherwise specified. The maximum junction temperature for a LM329 is 100°C. For operating at elevated temperature. The TO-92 package, the derating is based on 180°C/W junction to ambient with 0.4″ leads from a PC board and 160°C/ W junction to ambient with 0.125″ lead length to a PC board. Note 3: These changes are tested on a pulsed basis with a low duty-cycle. For changes versus temperature, compute in terms of tempco. Note 4: www.national.com 2 LM329 Typical Applications Low Cost 0–25V Regulator 571407 Adjustable Bipolar Output Reference 571408 0V to 20V Power Reference 571409 3 www.national.com LM329 External Reference for Temperature Transducer 571402 Positive Current Source 571411 Buffered Reference with Single Supply 571403 www.national.com 4 LM329 Schematic Diagram 571410 Typical Performance Characteristics Reverse Characteristics Reverse Voltage Change 571413 571417 Forward Characteristics Response Time 571414 571415 5 www.national.com LM329 Dynamic Impedance Zener Noise Voltage 571416 571418 Low Frequency Noise Voltage 571405 www.national.com 6 LM329 Physical Dimensions inches (millimeters) unless otherwise noted Plastic Package Order Number LM329DZ, NS Package Z03A 7 www.national.com LM329 Precision Reference 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 www.national.com/webench Audio www.national.com/audio Analog University www.national.com/AU Clock Conditioners www.national.com/timing App Notes www.national.com/appnotes Data Converters www.national.com/adc Distributors www.national.com/contacts Displays www.national.com/displays Green Compliance www.national.com/quality/green Ethernet www.national.com/ethernet Packaging www.national.com/packaging Interface www.national.com/interface Quality and Reliability www.national.com/quality LVDS www.national.com/lvds Reference Designs www.national.com/refdesigns Power Management www.national.com/power Feedback www.national.com/feedback Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www.national.com/led PowerWise www.national.com/powerwise Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors Wireless (PLL/VCO) www.national.com/wireless THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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