Microsemi Corporation LX1431IM, LX1431IDM, LX1431CM, LX1431CDM Datasheet

LIN DOC #:

P

ROGRAMMABLE REFERENCE

1431

LX1431

THE INFINITE POWER OF INNOVATION

DESCRIPTION KEY FEATURES

The LX1431 is an adjustable shunt voltage
regulator featuring 100mA sink capability, a

0.4% initial reference voltage tolerance and
a 0.3% typical temperature stability. This
product, which is ideal for use in Pentium
applications, is equipped with on-chip di­vider resistors, enabling it to be configured
as a 5V shunt regulator. In this configura­tion, the LX1431 has an initial voltage toler­ance of only 1% and requires no additional
external components. The Linfinity
LX1431EB evaluation board and design kit
is available to assist engineers in quickly
configuring the most efficient, cost-effective
Pentium designs.

The output voltage of the LX1431 may be
set to any value between 2.5V and 36V
through the addition of two external resis­tors, which is of particular importance in the

design of both adjustable and switching
power supplies. In addition, the nominal
internal current limit of 100mA may be de­creased with the addition of a single exter-

®

nal resistor.

For applications requiring an adjustable
reference, the Linfinity LX6431CLP, a simpli­fied three-pin programmable reference, may
be used. Because the LX6431 is pin-for-pin
compatible with Linfinity's earlier TL431, use
of this product provides designers a simple
migration path to the more robust LX6431.
A separate LX6431 data sheet is available
which details the specifics of this product.

In addition, Pentium designers may use
Linfinity's LX8585/8585A 4.6A or LX8584/
8584A 7A Low Dropout Regulators to achieve
the most optimum motherboard configura­tion.

PRODUCT HIGHLIGHT

THE LX8584A AND LX1431 IN 75 AND 166MHZ P54C PROCESSOR APPLICATIONS USING 3.3V CACHE

5V

220µF
10V
Low ESR
from
Sanyo

V

IN

LX8584A

ADJ

0.1µF
50V

V

1

3

23

OUT

250pF

2

+V+V+

V

LX1431

SGND FGND

1kW

COL

0.01µF

1kW

1

8

REF

65

2.84kW

0.1%

330µF, 6.3V

Oscon Type

from Sanyo

1k

0.1%

P RODUCTION DATA SHEET

p GUARANTEED 0.4% INITIAL VOLTAGE

TOLERANCE

p 0.1Ω TYPICAL DYNAMIC OUTPUT

IMPEDANCE

p FAST TURN-ON

p SINK CURRENT CAPABILITY, 1mA TO 100mA
p LOW REFERENCE PIN CURRENT

APPLICATIONS

■ LINEAR REGULATORS

■ ADJUSTABLE POWER SUPPLIES

■ SWITCHING POWER SUPPLIES

■ LX1431EB EVALUATION BOARD FOR

PENTIUM APPLICATIONS AVAILABLE.
CONSULT FACTORY.

VO 7A

(See Table Below)

3x

Low ESR

21k
1%

JP1

PLACE IN µP SOCKET CAVITY

100µF x 6

10V

AVX TYPE

TPS

1µF x 10
SMD

µP

Load

Copyright © 1997
Rev. 1.2 4/97

V

O

JP1 TYPICAL APPLICATION

3.50 Short 120/166MHz, VRE, 3.3V Cache

3.38 Open 75/90/100/133MHz, STND, 3.3V Cache

PACKAGE ORDER INFORMATION

T

(°C)

A

Plastic DIP

M

8-pin

0 to 70 LX1431CM LX1431CDM

-40 to 85 LX1431IM LX1431IDM

Note: All surface mount packages are available in Tape & Reel.

Append the letter "T" to part number (i.e. LX1431CDMT).

FOR FURTHER INFORMATION CALL [phone]

11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841

Thick traces represent high current traces which
must be low resistance / low inductance traces in
order to achieve good transient response.

Plastic SOIC

DM

8-pin

1

LX1431

PRODUCT DATABOOK 1996/1997

P

ROGRAMMABLE REFERENCE

RODUCTION DATA SHEET

P

ABSOLUTE MAXIMUM RATINGS (Note 1)

V+, V

COLLECTOR

V

, R

COMP

GND-F to GND-S ........................................................................................................ 0.7V

................................................................................................................. 36V

, R

, V

TOP

MID

...................................................................................................... 6V

REF

Operating Junction Temperature

Plastic (M, DM Packages) ..................................................................................... 150°C

Storage Temperature Range ...................................................................... -65°C to 150°C

Lead Temperature ..................................................................................................... 300°C

Note 1. Exceeding these ratings could cause damage to the device. All voltages are with respect

to Ground. Currents are positive into, negative out of the specified terminal.

THERMAL DATA

M PACKAGE:

THERMAL RESISTANCE-JUNCTION TO AMBIENT,

θθ

θ

θθ

JA

95°C/W

DM PACKAGE:

D

θθ

θ

θθ

x θ

JA

).

JA

THERMAL RESISTANCE-JUNCTION TO AMBIENT,

Junction Temperature Calculation: T

numbers are guidelines for the thermal performance of the device/pc-board system.

The θ

JA

All of the above assume no ambient airflow.

= TA + (P

J

165°C/W

BLOCK DIAGRAM

R

TOP

+

V

COMP COLLECTOR

PACKAGE PIN OUTS

COLLECTOR

COLLECTOR

COMP

1 8

2 7

COMP

+

3 6

V

4 5

R

TOP

M PACKAGE

(Top View)

1 8

2 7

+

3 6

V

4 5

R

TOP

DM PACKAGE

(Top View)

REF
R

MID

GND-F
GND-S

REF
R

MID

GND-F
GND-S

REF

R

MID

432 1

5K

8

gm=
60µA/V

7

5K

2.5V

65

GND-SENSE GND-FORCE

2

Copyright © 1997

Rev. 1.2 4/97

PRODUCT DATABOOK 1996/1997

LX1431

P

ROGRAMMABLE REFERENCE

P RODUCTION DAT A SHEET

ELECTRICAL CHARACTERISTICS

(Unless otherwise specified, these specifications apply over the operating ambient temperatures for LX1431C with 0°C ≤ TA ≤ 70°C, LX1431I with -40°C ≤ TA ≤ 85°C.)

Parameter

Reference Voltage

Reference Drift ∆V
Voltage Ratio, Reference to Cathode ∆V

(Open Loop Gain) ∆V

Reference Input Current

Minimum Operating Current I

Off-State Cathode Current

Off-State Collector Leakage Current

Dynamic Impedance [Z

Collector Current Limit I

Symbol

V

REF

/∆TV

REF

REFIK

KA

[I

]

REF

MINVKA

]

[I

OFF

]

[I

LEAK

]VKA = V

KA

LIM

Test Conditions

VKA = 5V, IK = 2mA, TA = 25°C
VKA = 5V, IK = 2mA

= 5V, IK = 2mA

KA

= 2mA, VKA = 3V to 36V

VKA = 5V, TA = 25°C
VKA = 5V

= V

to 36V, TA = 25°C

REF

VKA = 36V, V
VKA = 36V, V

V

= 36V, V+ = 5V, V

COLL

V

= 36V, V+ = 5V, V

COLL

VKA = V

= 0V, TA = 25°C

REF

= 0V

REF

, I

= 1mA to 100mA, f ≤ 1kHz, T

REF

K

+ 50mV

REF

= 2.4V, TA = 25°C

REF

= 2.4V

REF

5V Reference Output Internal Divider Used, IK = 2mA, TA = +25°C

= 25°C

A

LX1431I

Min. Typ. Max. Min. Typ. Max.

2490 2500 2510 2490 2500 2510 mV
2465 2535 2480 2520 mV

50 30 ppm/°C

0.2 1.0 0.2 1.0 mV/V

0.2 1 0.2 1 µA

1.5 1.2 µA

0.6 1 0.6 1 mA
11µA

15 2 µA

11µA
52µA

0.1 0.1 Ω

80 360 100 360 mA

4950 5000 5050 4950 5000 5050 mV

LX1431C

Units

Copyright © 1997
Rev. 1.2 4/97

3