LM431.pdf

March 2002

LM431

Adjustable Precision Zener Shunt Regulator

General Description

The LM431 is a 3-terminal adjustable shunt regulator with

guaranteed temperature stability over the entire temperature

range of operation. It is now available in a chip sized pack-

age (4-Bump micro SMD) using National’s micro SMD pack-

age technology. The output voltage may be set at any level

greater than 2.5V (V REF ) up to 36V merely by selecting two

external resistors that act as a voltage divided network. Due

to the sharp turn-on characteristics this device is an excel-

lent replacement for many zener diode applications.

Features

n Average temperature coefficient 50 ppm/˚C

n Temperature compensated for operation over the full

temperature range

n Programmable output voltage

n Fast turn-on response

n Low output noise

n LM431 in micro SMD package

n See AN-1112 for micro SMD considerations

Connection Diagrams

TO-92: Plastic Package

SOT-23: 3-Lead Small Outline

DS010055-28

DS010055-1

Top View

4-Bump micro SMD

SO-8: 8-Pin Surface Mount

DS010055-54

DS010055-2

Top View

(bump side down)

Top view

Note: * NC = Not internally connected. Must be electrically isolated from the

rest of the circuit for the microSMD package.

DS010055

www.national.com

Ordering Information

Package Typical Accuracy Order Number/Package Marking Temperature

Range

Transport Media

NSC

Drawing

0.5%

TO-92

LM431CCZ/

LM431CCZ

LM431BCZ/

LM431BCZ

LM431ACZ/

LM431ACZ

0˚C to +70˚C

Rails

Z03A

LM431CIZ/

LM431CIZ

LM431BIZ/

LM431BIZ

LM431AIZ/

LM431AIZ

−40˚C to +85˚C

SO-8

LM431CCM/

431CCM

LM431BCM/

431BCM

LM431ACM/

LM431ACM

0˚C to +70˚C

Rails and Tape &Reel

M08A

LM431CIM/

431CIM

LM431BIM/

431BIM

LM431AIM/

LM431AIM

−40˚C to +85˚C

SOT-23

LM431CCM3/

N1B

LM431BCM3/

N1D

LM431ACM3/

N1F

0˚C to +70˚C

Rails and Tape &Reel

MF03A

LM431CIM3

N1A

LM431BIM3

N1C

LM431AIM3

N1E

−40˚C to +85˚C

micro SMD

–

LM431AIBP

LM431AIBPX(Note 1)

−40˚C to +85˚C

250 Units Tape and Reel

3k Units Tape and Reel

BPA04AFB

Note 1: The micro SMD package marking is a 1 digit manufacturing Date Code only

micro SMD Top View Marking Example

DS010055-56

www.national.com

Symbol and Functional Diagrams

DS010055-99

DS010055-55

DC Test Circuits

DS010055-4

FIGURE 1. Test Circuit for V Z =V REF

DS010055-5

Note: V Z =V REF (1 + R1/R2) + I REF • R1

FIGURE 2. Test Circuit for V Z > V REF

DS010055-6

FIGURE 3. Test Circuit for Off-State Current

www.national.com

Absolute Maximum Ratings (Note 2)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales Office/

Distributors for availability and specifications.

Storage Temperature Range

Reference Voltage

−0.5V

Reference Input Current

10 mA

−65˚C to +150˚C

Internal Power Dissipation (Notes 3, 4)

TO-92 Package

SO-8 Package

SOT-23 Package

0.78W

0.81W

0.28W

Operating Temperature Range

Industrial (LM431xI)

micro SMD Package

0.30W

−40˚C to +85˚C

Commercial (LM431xC)

0˚C to +70˚C

Operating Conditions

Soldering Information

Infrared or Convection (20 sec.)

235˚C

Min

Max

Cathode Voltage

V REF

37V

Wave Soldering (10 sec.)

260˚C (lead temp.)

Cathode Current

1.0 mA

100 mA

Cathode Voltage

37V

Continuous Cathode Current

−10 mA to +150 mA

LM431

Electrical Characteristics

T A = 25˚C unless otherwise specified

Symbol

Parameter

Conditions

Min

Typ

Max

Units

V REF

Reference Voltage

V Z =V REF ,I I = 10 mA

2.440

2.495

2.550

LM431A (Figure 1 )

V Z =V REF ,I I = 10 mA

2.470

2.495

2.520

LM431B (Figure 1 )

V Z =V REF ,I I = 10 mA

2.485

2.500

2.510

LM431C (Figure 1 )

V DEV

Deviation of Reference Input Voltage Over

V Z =V REF ,I I = 10 mA,

8.0

Temperature (Note 5)

T A = Full Range (Figure 1 )

Ratio of the Change in Reference Voltage

I Z =10mA V Z from V REF to 10V

−1.4

−2.7

mV/V

to the Change in Cathode Voltage

(Figure 2 ) V Z from 10V to 36V

−1.0

−2.0

I REF

Reference Input Current

R 1 =10k

,R 2 = ¥ ,

2.0

4.0

µA

I I =10mA(Figure 2 )

µ I REF

Deviation of Reference Input Current over

R 1 =10k

,R 2 = ¥ ,

Temperature

I I = 10 mA,

0.4

1.2

µA

T A = Full Range (Figure 2 )

I Z(MIN)

Minimum Cathode Current for Regulation

V Z =V REF (Figure 1 )

0.4

1.0

I Z(OFF)

Off-State Current

V Z = 36V, V REF =0V(Figure 3 )

0.3

1.0

µA

r Z

Dynamic Output Impedance (Note 6)

V Z =V REF , LM431A,

0.75

Frequency = 0 Hz (Figure 1 )

V Z =V REF , LM431B, LM431C

0.50

Frequency = 0 Hz (Figure 1 )

Note 2: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Electrical specifications do not apply when operating the device

beyond its rated operating conditions.

Note 3: T J Max = 150˚C.

Note 4: Ratings apply to ambient temperature at 25˚C. Above this temperature, derate the TO-92 at 6.2 mW/˚C, the SO-8 at 6.5 mW/˚C, the SOT-23 at 2.2 mW/˚C

and the micro SMD at 3mW/˚C.

Note 5: Deviation of reference input voltage, V DEV , is defined as the maximum variation of the reference input voltage over the full temperature range.

www.national.com

LM431

Electrical Characteristics (Continued)

DS010055-7

The average temperature coefficient of the reference input voltage,

µ V REF , is defined as:

V REF can be positive or negative depending on whether the slope is positive or negative.

Example: V DEV = 8.0 mV, V REF = 2495 mV, T 2 −T 1 = 70˚C, slope is positive.

Note 6: The dynamic output impedance, r Z , is defined as:

When the device is programmed with two external resistors, R1 and R2, (see Figure 2 ), the dynamic output impedance of the overall circuit, r Z , is defined as:

Equivalent Circuit

DS010055-3

www.national.com

Where:

T 2 −T 1 = full temperature change (0-70˚C).

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: