P RODU C T ION D AT A S HEET
T HE
I NFI N ITE
P O W ER
OF
I N NOVATIO N
Not Recommended For New Design
L IN F IN IT Y M IC ROEL E C TRON IC S I NC .
11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: 714-893-2570
1
Copyright
1997
Rev. 1.2a,2005-03-08
LX1431
P RO GR AMM AB L E R EFE R ENCE
DESCRI PTI O N
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 external 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.
IMPORTANT:
For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
KEY FEATUR ES
Guaranteed 0.4% Initial Voltage
Tolerance
0.1
Typical Dynamic Output
Impedance
Fast Turn-on
Sink Current Capability, 1mA to
100mA
Low Reference Pin Current
APPLI CATI ONS
Linear Regulators
Adjustable Power Supplies
Switching Power Supplies
LX1432EB Evaluation Board For
Pentium Applications Available
PRODUCT H I GHLIGHT
THE LX8584A & LX431 IN 75 & 166MHZ P54C PROCESSOR APPLICATIONS USING 3.3V CACHE
Thick traces represent high current traces which
must be low resistance / low inductance traces in
order to achieve good transient response.
P
Load
100F x 6
10V
AVX TYPE
TPS
1F x 10
SMD
1k
0.1%
2.84k W
0.1%
COL
V+
SGND
FGND
REF
LX1431
VIN
VOUT
ADJ
1kW
0.01F
3x
330F, 6.3V
Low ESR
Oscon Type
from Sanyo
2
3
1
6
5
8
1
3
0.1F
50V
220F
10V
Low ESR
from
Sanyo
5V
PLACE IN
P SOCKET CAVITY
LX8584A
VO 7A
(See Table Below)
2
250pF
21k
1%
JP1
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 INFO
M
Plastic DIP
8-Pin
DM
Plastic SOIC
8-Pin
TA (
°C)
RoHS Compliant / Pb-free
Transition DC: 0503
RoHS Compliant / Pb-free
Transition DC: 0440
0 to 70
LX1431CM
LX1431CDM
-40 to 85
LX1431IM
LX1431IDM
Note: Available in Tape & Reel. Append the letters “TR” to the part number (i.e. LX1431CDM-TR).