
Microsemi 
Linfinity Microelectronics Division 
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 
Page 1
Copyright 
 2000 
Rev. 2.1d, 2001-03-15 
W
M
.
LX8384x-xx
5A Low Dropout Positive Regulators 
P
RODUCTION
A  M I C R O S E M I  C O M P A N Y
The LX8384/84A/84B Series ICs are 
positive regulators designed to provide 5A 
output current. These regulators yield 
higher efficiency than currently available 
devices with all internal circuitry designed 
to operate down to a 1V input-to-output 
differential. In each of these products, the 
dropout voltage is fully specified as a 
function of load current. Dropout is 
guaranteed at a maximum of 1.3V (8384A) 
and 1.5V (8384
) 
at maximum output 
current, decreasing at lower load currents.   
In addition, on-chip trimming adjusts the 
reference voltage tolerance to 1% maximum 
at room temperature and 2% maximum over 
the 0 to 125°C range for the LX8384A, 
making this ideal for the Pentium P54C-
VRE specification.  The LX8384B offers 
0.8% tolerance at room temperature and 
1.0% maximum over line, load and 
temperature.  Fixed versions are also  
available and specified in the Available 
Options table below.  
The LX8384/84A/84B Series devices are 
pin-compatible with earlier 3-terminal 
regulators, such as the 117 series products, 
but they do require input and output 
capacitors. A minimum 10μF capacitor is 
required on the input and a 15μF or greater 
on the output of these new devices for 
stability. Although, these capacitors are 
generally included in most regulator 
designs.   
The LX8384/84A/84B Series quiescent 
current flows into the load, thereby 
increasing efficiency. This feature contrasts 
with PNP regulators where up to 10% of the 
output current is wasted as quiescent 
current. The LX8384-xxI is specified over 
the industrial temperature range of -25°C to 
125°C, 
while 
the 
xxC/84B-xxC 
is 
specified 
commercial range of 0°C to 125°C.
LX8384-xxC/84A-
over 
the 
IMPORTANT:
For the most current data, consult 
MICROSEMI
’s website: 
http://www.microsemi.com
*1500μF
6MV1500GX
Sanyo
LX8384A
121
0.1%
218
0.1%
IN
ADJ
OUT
5V
3.5V
at 5A
1500μF
5x 6MV1500GX
Sanyo
+
+
* Capacitors must have < 20m
Total ESR for the VRE Specification
An Application of the LX8384A for the Pentium P54C Processors Meeting VRE Specification. 
Three-Terminal Adjustable Or 
Fixed Output 
Guaranteed < 1.3V Headroom a 
5A (LX8384A) 
Guaranteed 2.0% Max. 
Reference Tolerance (LX8384A) 
Guaranteed 1.0% Max. 
Reference Tolerance (LX8384B) 
0.015% Line Regulation 
0.15% Load Regulation 
Pentium
 Processor VRE 
Application 
High Efficiency Linear 
Regulators 
Power Regulators For Switching 
Power Supplies 
Battery Chargers 
Constant Current Regulators 
Cyrix
 6x86 
AMD-K5 
LX8384/84A/84B-00 
Adjustable 
LX8384/84A/84B-15 
1.5V 
LX8384/84A/84B-33 
3.3V 
Table 1
 - Available Options 
T
A
 (
°
C) 
Max Ref 
Accuracy 
2.0% 
2.0% 
1.0% 
2.0% 
Max Dropout 
Voltage 
1.5V 
1.3V 
1.3V 
1.5V 
DT
Plastic TO-252 
 (D-Pak) 3-Pin 
LX8384-xxCDT 
LX8384A-xxCDT 
LX8384B-xxCDT 
LX8384-xxIDT 
P
Plastic TO-220 
 3-Pin 
LX8384-xxCP 
LX8384A-xxCP 
LX8384B-xxCP 
LX8384-xxIP 
DD 
Plastic TO-263 
3-Pin
LX8384-xxCDD 
LX8384A-xxCDD 
LX8384B-xxCDD 
LX8384-xxIDD 
0 to 125 
-25 to 125 
Note:  Available in Tape & Reel.   
Append the letter “T” to the part number. (i.e. LX8384-xxCPT) 
L
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