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 cir-
cuits are precision 2.5V shunt regulator diodes. These
monolithic

voltage

references

operate

low-temperature-coefficient 2.5V zener with 0.2

dynamic

impedance. A third terminal on the LM136-2.5 allows the ref-
erence voltage and temperature coefficient to be trimmed
easily.

The LM136-2.5 series is useful as a precision 2.5V low volt-
age 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 -55°C to +125°C
while the LM236-2.5 is rated over a -25°C to +85°C tem-
perature range.

The LM336-2.5 is rated for operation over a 0°C to +70°C
temperature range. See the connection diagrams for avail-
able packages.

Features

Low temperature coefficient

Wide operating current of 400 µA to 10 mA

0.2

dynamic impedance

1% initial tolerance available

Guaranteed temperature stability

Easily trimmed for minimum temperature drift

Fast turn-on

Three lead transistor package

Connection Diagrams

TO-92

Plastic Package

DS005715-8

Bottom View

Order Number LM236Z-2.5,

LM236AZ-2.5, LM336Z-2.5 or LM336BZ-2.5

See NS Package Number Z03A

TO-46

Metal Can Package

DS005715-20

Bottom View

Order Number LM136H-2.5,

LM136H-2.5/883, LM236H-2.5,

LM136AH-2.5, LM136AH-2.5/883

or LM236AH-2.5

See NS Package Number H03H

May 1998

LM136-2.5/LM236-2.5/LM336-2.5V

Reference

Diode

DS005715

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.

Reverse Current

15 mA

Forward Current

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

LM336

0°C to +70°C

Soldering Information

TO-92 Package (10 sec.)

260°C

TO-46 Package (10 sec.)

300°C

SO Package

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)

LM136A-2.5/LM236A-2.5

LM336B-2.5

Parameter

Conditions

LM136-2.5/LM236-2.5

LM336-2.5

Units

Min

Typ

Max

Min

Typ

Max

Reverse Breakdown Voltage

=25°C, I

=1 mA

LM136, LM236, LM336

2.440

2.490

2.540

2.390

2.490

2.590

LM136A, LM236A, LM336B

2.465

2.490

2.515

2.440

2.490

2.540

Reverse Breakdown Change

=25°C,

2.6

With Current

400 µA

10 mA

Reverse Dynamic Impedance

=25°C, I

=1 mA, f = 100 Hz

0.2

0.6

0.2

Temperature Stability

Adjusted to 2.490V

(Note 4)

=1 mA, Figure 2

0°C

70°C (LM336)

1.8

-25°C

+85°C

3.5

(LM236H, LM236Z)

-25°C

+85°C (LM236M)

7.5

-55°C

+125°C (LM136)

Reverse Breakdown Change

400 µA

10 mA

With Current

Reverse Dynamic Impedance

=1 mA

0.4

1.4

Long Term Stability

=25°C

0.1°C, I

=1 mA,

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, T

max is:

LM136

150°C

LM236

125°C

LM336

100°C

Thermal Resistance

TO-92

TO-46

SO-8

(Junction to Ambient)

180°C/W (0.4" leads)

440°C/W

165°C/W

170°C/W (0.125" lead)

(Junction to Case)

n/a

80°C/W

n/a

Note 3: Unless otherwise specified, the LM136-2.5 is specified from -55°C

+125°C, the LM236-2.5 from -25°C

+85°C and the LM336-2.5 from 0°C

+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 in-
dicated temperature and supply voltage ranges. These limits are not used to calculate outgoing quality levels. Stability is defined as the maximum change in V

ref

from

25°C to T

(min) or T

(max).

www.national.com

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 co-
efficient can be adjusted to optimize circuit performance.

Figure 1 shows an LM136 with a 10k potentiometer for ad-
justing 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 resis-
tance of R1 is not critical and any value from 2k to 20k will
work.

DS005715-28

FIGURE 1. LM136 With Pot for Adjustment

of Breakdown Voltage

(Trim Range =

120 mV typical)

DS005715-29

FIGURE 2. Temperature Coefficient Adjustment

(Trim Range =

70 mV typical)

Low Cost 2 Amp Switching Regulator

DS005715-5

L1 60 turns #16 wire on Arnold Core A-254168-2

Efficiency

80%

Ð­Ð»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: LM136H-2.5

ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: LM136H-2.5