LM185-1.2/LM285-1.2/LM385-1.2
Micropower Voltage Reference Diode

General Description

The

LM185-1.2/LM285-1.2/LM385-1.2

are

micropower

2-terminal band-gap voltage regulator diodes. Operating
over a 10µA to 20mA current range, they feature exception-
ally low dynamic impedance and good temperature stability.
On-chip trimming is used to provide tight voltage tolerance.
Since the LM185-1.2 band-gap reference uses only transis-
tors and resistors, low noise and good long term stability
result.

Careful design of the LM185-1.2 has made the device ex-
ceptionally tolerant of capacitive loading, making it easy to
use in almost any reference application. The wide dynamic
operating range allows its use with widely varying supplies
with excellent regulation.

The extremely low power drain of the LM185-1.2 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.

Further, the wide operating current allows it to replace older
references with a tighter tolerance part.

The LM185-1.2 is rated for operation over a -55°C to 125°C
temperature range while the LM285-1.2 is rated -40°C to
85°C and the LM385-1.2 0°C to 70°C. The LM185-1.2/
LM285-1.2 are available in a hermetic TO-46 package and
the LM285-1.2/LM385-1.2 are also available in a low-cost
TO-92 molded package, as well as SO and SOT-23. The
LM185-1.2 is also available in a hermetic leadless chip
carrier package.

Features

1% and 2% initial tolerance

Operating current of 10µA to 20mA

dynamic impedance

Low temperature coefficient

Low voltage reference -- 1.235V

2.5V device and adjustable device also available

LM185-2.5 series and LM185 series, respectively

Connection Diagrams

T0-92

Plastic Package (Z)

SOT23

00551810

Bottom View

Order Number LM285Z-1.2,

LM285BXZ-1.2, LM285BYZ-1.2

LM385Z-1.2, LM385BZ-1.2

LM385BXZ-1.2 or LM385BYZ-1.2

See NS Package Number Z03A

00551833

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

Order Number LM385M3-1.2

See NS Package Number MF03A

May 2003

LM185-1.2/LM285-1.2/LM385-1.2

Micropower

oltage

Reference

Diode

DS005518

www.national.com

Absolute Maximum Ratings

(Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

(Note 2)

Reverse Current

30mA

Forward Current

10mA

Operating Temperature Range (Note 3)

LM185-1.2

-55°C to +125°C

LM285-1.2

-40°C to +85°C

LM385-1.2

0°C to 70°C

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 Pkg.

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)

LM185-1.2

LM185BX-1.2

LM385B-1.2

LM185BY-1.2

LM385BX-1.2

LM385-1.2

LM285-1.2

LM385BY-1.2

Units

Parameter

Conditions

Typ

LM285BX-1.2

(Limit)

LM285BY-1.2

Tested

Design

Tested

Design

Tested

Design

Limit

(Notes

5, 8)

(Note 6)

(Note 5)

(Note 6)

(Note 5)

(Note 6)

Reverse Breakdown

= 25°C,

1.235

1.223

1.205

V(Min)

Voltage

10µA

20mA

1.247

1.260

V(Max)

Minimum Operating

µA

Current

LM385M3-1.2

(Max)

Reverse Breakdown

10µA

1mA

1.5

Voltage Change

(Max)

with Current

1mA

20mA

(Max)

Reverse Dynamic

= 100µA, f = 20Hz

Impedance

Wideband Noise

= 100µA,

µV

(rms)

10Hz

f 10kHz

Long Term Stability

= 100µA, T = 1000

Hr,

ppm

= 25°C

0.1°C

Average

Temperature

= 100µA

Coefficient (Note 7)

X Suffix

ppm/°C

Y Suffix

ppm/°C

All Others

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-1.2 for military specifications.

Note 3: For elevated temperature operation, T

max is:

LM185

150°C

LM285

125°C

LM385

100°C

LM185-1.2/LM285-1.2/LM385-1.2

www.national.com

Thermal Resistance

TO-92

TO-46

SO-8

SOT23

(junction to ambient)

180°C/W (0.4" leads)

440°C/W

165°C/W

283°C/W

170°C/W (0.125" leads)

(junction to case)

N/A

80°C/W

N/A

Note 4: Parameters identified with boldface type apply at temperature extremes. All other numbers apply at T

= T

= 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 T

MAX

and T

MIN

, divided by T

MAX

- T

MIN

. 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 is available on request.

Typical Performance Characteristics

Reverse Characteristics

00551813

00551814

Forward Characteristics

Temperature Drift of 3

Representative Units

00551815

00551816

Reverse Dynamic Impedance

00551817

00551818

LM185-1.2/LM285-1.2/LM385-1.2

Document Outline

Ð­Ð»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: LM185BYH-1.2

Document Outline

ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: LM185BYH-1.2