LM385Z-2.5/T7/NOPB - NATIONAL SEMICONDUCTOR

January 30, 2008

LM185-2.5/LM285-2.5/LM385-2.5

Micropower Voltage Reference Diode

General Description

The LM185-2.5/LM285-2.5/LM385-2.5 are micropower 2-ter-

minal band-gap voltage regulator diodes. Operating over a 20

μA to 20 mA current range, they feature exceptionally low dy-

namic impedance and good temperature stability. On-chip

trimming is used to provide tight voltage tolerance. Since the

LM-185-2.5 band-gap reference uses only transistors and re-

sistors, low noise and good long term stability result.

Careful design of the LM185-2.5 has made the device excep-

tionally tolerant of capacitive loading, making it easy to use in

almost any reference application. The wide dynamic operat-

ing range allows its use with widely varying supplies with

excellent regulation.

The extremely low power drain of the LM185-2.5 makes it

useful for micropower circuitry. This voltage reference can be

used to make portable meters, regulators or general purpose

analog circuitry with battery life approaching shelf life. Fur-

ther, the wide operating current allows it to replace older

references with a tighter tolerance part. For applications re-

quiring 1.2V see LM185-1.2.

The LM185-2.5 is rated for operation over a −55°C to 125°C

temperature range while the LM285-2.5 is rated −40°C to 85°

C and the LM385-2.5 0°C to 70°C. The LM185-2.5/LM285-2.5

are available in a hermetic TO-46 package and the

LM285-2.5/LM385-2.5 are also available in a low-cost TO-92

molded package, as well as S.O. and SOT-23. The

LM185-2.5 is also available in a hermetic leadless chip carrier

package.

Features

■±20 mV (±0.8%) max. initial tolerance (A grade)

■Operating current of 20 μA to 20 mA

■0.6Ω dynamic impedance (A grade)

■Low temperature coefficient

■Low voltage reference—2.5V

■1.2V device and adjustable device also available—

LM185-1.2 series and LM185 series, respectively

Connection Diagrams

TO-92

Plastic Package

551908

Bottom View

Order Number LM285Z-2.5,

LM285BXZ-2.5, LM285BYZ-2.5

LM385Z-2.5, LM385AXZ-2.5

LM385AYZ-2.5, LM385BZ-2.5,

LM385BXZ-2.5 or LM385BYZ-2.5

See NS Package Number Z03A

SO Package

551911

Order Number LM285M-2.5,

LM285BXM-2.5, LM285BYM-2.5

LM385M-2.5, LM385BM-2.5

LM385BXM-2.5 or LM385BYM-2.5

See NS Package Number M08A

SOT-23

551929

* Pin 3 is attached to the Die Attach Pad (DAP) and should be connected to Pin 2 or left floating.

Order Number LM385M3-2.5

See NS Package Number MA03B

LM185-2.5/LM285-2.5/LM385-2.5 Micropower Voltage Reference Diode

LCC

Leadless Chip Carrier

551914

Order Number LM185E-2.5/883

See NS Package Number E20A

TO-46

Metal Can Package

551913

Bottom View

Order Number LM185H-2.5,

LM185H-2.5/883, LM185BXH-2.5,

LM185BXH-2.5/883, LM185BYH-2.5,

LM185BYH2.5/883, LM285H-2.5,

or LM285BYH-2.5

See NS Package Number H02A

www.national.com 2

LM185-2.5/LM285-2.5/LM385-2.5

Absolute Maximum Ratings (Notes 1, 2)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales Office/

Distributors for availability and specifications.

Reverse Current 30 mA

Forward Current 10 mA

Operating Temperature

Range (Note 3)

LM185-2.5 −55°C to + 125°C

LM285-2.5 −40°C to + 85°C

LM385-2.5 0°C to 70°C

ESD Susceptibility (Note 9) 2kV

Storage Temperature −55°C to + 150°C

Soldering Information

TO-92 Package (10 sec.) 260°C

TO-46 Package (10 sec.) 300°C

SO and SOT Package

Vapor Phase (60 sec.) 215°C

Infrared (15 sec.) 220°C

See AN-450 “Surface Mounting Methods and Their Effect on

Product Reliability” for other methods of soldering surface

mount devices.

Electrical Characteristics

(Note 4)

Parameter Conditions Typ

LM385A-2.5

Units

(Limits)

LM385AX-2.5

LM385AY-2.5

Tested Design

Limit Limit

(Note 5) (Note 6)

Reverse Breakdown IR = 100 μA2.500 2.480 V(Min)

Voltage 2.520 V(Max)

2.500 2.470 V(Min)

2.530 V(Max)

Minimum Operating 12 18 20 μA

Current (Max)

Reverse Breakdown IMIN ≤ IR ≤ 1mA 1 1.5 mV

Voltage Change with (Max)

Current 1 mA ≤ IR ≤ 20 mA 10 20 mV

(Max)

Reverse Dynamic IR = 100 μA, 0.2 0.6 Ω

Impedance f = 20 Hz 1.5

Wideband Noise (rms) IR = 100 μA120 μV

10 Hz ≤ f ≤ 10 kHz

Long Term Stability IR = 100 μA,

T = 1000 Hr, 20 ppm

TA = 25°C ±0.1°C

Average Temperature IMIN ≤ IR ≤ 20 mA

Coefficient (Note 7) X Suffix 30 ppm/°C

Y Suffix 50 (Max)

All Others 150

3 www.national.com

LM185-2.5/LM285-2.5/LM385-2.5

Electrical Characteristics

LM185-2.5

LM185BX-2.5 LM385B-2.5

LM185BY-2.5 LM385BX-2.5 LM385-2.5 Units

LM285-2.5 LM385BY-2.5 (Limit)

Parameter Conditions Typ LM285BX-2.5

LM285BY-2.5

Tested Design Tested Design Tested Design

Limit Limit Limit Limit Limit Limit

(Notes 5, 8) (Note 6) (Note 5) (Note 6) (Note 5) (Note 6)

Reverse

Breakdown

TA = 25°C, 2.5 2.462 2.462 2.425 V(Min)

Voltage 20 μA ≤ IR ≤ 20 mA 2.538 2.538 2.575 V(Max)

Minimum Operating

Current

13 20 30 20 30 20 30 μA

(Max)

LM385M3-2.5 15 20

Reverse

Breakdown Voltage

Change with

Current

20 μA ≤ IR ≤ 1 mA 1 1.5 2.0 2.5 2.0 2.5 mV

(Max)

1 mA ≤ IR ≤ 20 mA 10 20 20 25 20 25 mV

(Max)

Reverse Dynamic IR = 100 μA, 1 Ω

Impedance f = 20 Hz

Wideband Noise

(rms)

IR = 100 μA, 120 μV

10 Hz ≤ f ≤ 10 kHz

Long Term Stability IR = 100 μA,

T = 1000 Hr, 20 ppm

TA = 25°C ±0.1°C

Average

Temperature

IR = 100 μA

Coefficient (Note 7) X Suffix 30 30 ppm/°C

Y Suffix 50 50 ppm/°C

All Others 150 150 150 ppm/°C

(Max)

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is

intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics.

The guaranteed specifications apply only for the test conditions listed.

Note 2: Refer to RETS185H-2.5 for military specifications.

Note 3: For elevated temperature operation, TJ MAX is:

LM185 150°C

LM285 125°C

LM385 100°C

Thermal Resistance TO-92 TO-46 SO-8 SOT-23

θja (Junction to Ambient) 180°C/W (0.4″ Leads) 440°C/W 165°C/W 283°C/W

170°C/W (0.125″ Leads)

θjc (Junction to Case) N/A 80°C/W N/A N/A

Note 4: Parameters identified with boldface type apply at temperature extremes. All other numbers apply at TA = TJ = 25°C.

Note 5: Guaranteed and 100% production tested.

Note 6: Guaranteed, but not 100% production tested. These limits are not used to calculate average outgoing quality levels.

Note 7: The average temperature coefficient is defined as the maximum deviation of reference voltage at all measured temperatures between the operating

TMAX and TMIN, divided by TMAX–TMIN. The measured temperatures are −55°C, −40°C, 0°C, 25°C, 70°C, 85°C, 125°C.

Note 8: A military RETS electrical specification available on request.

Note 9: The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin.

www.national.com 4

LM185-2.5/LM285-2.5/LM385-2.5

Typical Performance Characteristics

Reverse Characteristics

551915

Reverse Characteristics

551916

Forward Characteristics

551917

Temperature Drift

551918

Reverse Dynamic

Impedance

551919

Reverse Dynamic

Impedance

551920

5 www.national.com

LM185-2.5/LM285-2.5/LM385-2.5

Noise Voltage

551921

Filtered Output Noise

551922

Response Time

551923

Applications

Wide Input Range Reference

551912

Micropower Reference from 9V Battery

551902

LM385-2.5 Applications

Micropower 5V Reference

551909

Note 10: IQ ≃ 40 μA

www.national.com 6

LM185-2.5/LM285-2.5/LM385-2.5

Micropower 10V Reference

551910

Note 11: IQ ≃ 30 μA standby current

PRECISION 1 μA to 1 mA CURRENT SOURCES

551924

551925

7 www.national.com

LM185-2.5/LM285-2.5/LM385-2.5

METER THERMOMETERS

0°C–100°C Thermomemter

551926

Calibration

1. Short LM385-2.5, adjust R3 for IOUT=temp at 1μA/°K

Remove short, adjust R2 for correct reading in centigrade

0°F–50°F Thermomemter

551927

Calibration

1. Short LM385-2.5, adjust R3 for IOUT=temp at 1.8 μA/°K

Remove short, adjust R2 for correct reading in °F

www.national.com 8

LM185-2.5/LM285-2.5/LM385-2.5

Micropower Thermocouple Cold Junction Compensator

551906

Adjustment Procedure

1. Adjust TC ADJ pot until voltage across R1 equals Kelvin temperature multiplied by the thermocouple Seebeck coefficient.

2. Adjust zero ADJ pot until voltage across R2 equals the thermocouple Seebeck coefficient multiplied by 273.2.

Seebeck Voltage Voltage

Thermocouple Co- R1 R2 Across R1 Across R2

Type efficient (Ω) (Ω) @25°C (mV)

(μV/°C) (mV)

J 52.3 523 1.24k 15.60 14.32

T 42.8 432 1k 12.77 11.78

K 40.8 412 953Ω 12.17 11.17

S 6.4 63.4 150Ω 1.908 1.766

Typical supply current 50 μA

Improving Regulation of Adjstable Regulators

551907

9 www.national.com

LM185-2.5/LM285-2.5/LM385-2.5

Schematic Diagram

551901

www.national.com 10

LM185-2.5/LM285-2.5/LM385-2.5

Physical Dimensions inches (millimeters) unless otherwise noted

Order Number LM185E-2.5/883

NS Package Number E20A

TO-46 Metal Can Package (H)

Order Number LM185H-2.5, LM185H-2.5/883, LM185BXH-2.5, LM185BXH-2.5/883,

LM185BYH-2.5, LM185BYH-2.5/883, LM285H-2.5, or LM285BYH-2.5

NS Package Number H02A

11 www.national.com

LM185-2.5/LM285-2.5/LM385-2.5

SOT-23 Package (M3)

Order Number LM385M3-2.5

NS Package Number MA03B

www.national.com 12

LM185-2.5/LM285-2.5/LM385-2.5

Small Outline (SO-8) Package (M)

Order Number LM285M-2.5, LM285BXM-2.5, LM285BYM-2.5,

LM385M-2.5, LM385BM-2.5, LM385BXM-2.5 or LM385BYM-2.5

NS Package Number M08A

13 www.national.com

LM185-2.5/LM285-2.5/LM385-2.5

TO-92 Plastic Package (Z)

Order Number LM285Z-2.5, LM285BXZ-2.5, LM285BYZ-2.5,

LM385Z-2.5, LM385AXZ-2.5, LM385AYZ-2.5,

LM385BZ-2.5, LM385BXZ-2.5 or LM385BYZ-2.5

NS Package Number Z03A

www.national.com 14

LM185-2.5/LM285-2.5/LM385-2.5

Notes

15 www.national.com

LM185-2.5/LM285-2.5/LM385-2.5

Notes

LM185-2.5/LM285-2.5/LM385-2.5 Micropower Voltage Reference Diode

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. NATIONAL MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY

OR COMPLETENESS OF THE CONTENTS OF THIS PUBLICATION AND RESERVES THE RIGHT TO MAKE CHANGES TO

SPECIFICATIONS AND PRODUCT DESCRIPTIONS AT ANY TIME WITHOUT NOTICE. NO LICENSE, WHETHER EXPRESS,

IMPLIED, ARISING BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS

DOCUMENT.

TESTING AND OTHER QUALITY CONTROLS ARE USED TO THE EXTENT NATIONAL DEEMS NECESSARY TO SUPPORT

NATIONAL’S PRODUCT WARRANTY. EXCEPT WHERE MANDATED BY GOVERNMENT REQUIREMENTS, TESTING OF ALL

PARAMETERS OF EACH PRODUCT IS NOT NECESSARILY PERFORMED. NATIONAL ASSUMES NO LIABILITY FOR

APPLICATIONS ASSISTANCE OR BUYER PRODUCT DESIGN. BUYERS ARE RESPONSIBLE FOR THEIR PRODUCTS AND

APPLICATIONS USING NATIONAL COMPONENTS. PRIOR TO USING OR DISTRIBUTING ANY PRODUCTS THAT INCLUDE

NATIONAL COMPONENTS, BUYERS SHOULD PROVIDE ADEQUATE DESIGN, TESTING AND OPERATING SAFEGUARDS.

EXCEPT AS PROVIDED IN NATIONAL’S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, NATIONAL ASSUMES NO

LIABILITY WHATSOEVER, AND NATIONAL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO THE SALE

AND/OR USE OF NATIONAL PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR

PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY

RIGHT.

LIFE SUPPORT POLICY

NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR

SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL

COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:

Life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and

whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected

to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform

can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness.

National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other

brand or product names may be trademarks or registered trademarks of their respective holders.

For the most current product information visit us at www.national.com

National Semiconductor

Americas Technical

Support Center

Email:

new.feedback@nsc.com

Tel: 1-800-272-9959

National Semiconductor Europe

Technical Support Center

Email: europe.support@nsc.com

German Tel: +49 (0) 180 5010 771

English Tel: +44 (0) 870 850 4288

National Semiconductor Asia

Pacific Technical Support Center

Email: ap.support@nsc.com

National Semiconductor Japan

Technical Support Center

Email: jpn.feedback@nsc.com