Document
LIN D O C #: 8554
LX8554-xx
5A E XTREMELY L OW D ROPOUT P OSITIVE R EGULATORS
T
H E
I
N F I N I T E
P
O W E R
O F
I
N N O VA T I O N
P
R O D U C T I O N
D
A T A
S
H E E T
DESCRIPTION The LX8554 series ICs are very low dropout three-terminal positive regulators with 5A rated output current. This product family is ideally suited for Pentium® Processor and Power PCTM applications requiring fast transient response. The LX8554 is guaranteed to have a dropout voltage under 1V at 5A load, making it ideal to provide well-regulated outputs of 2.5V to 3.6V with input supply as low as 4.75V. Fixed versions are also available and are specified in the Available Options table below. Current limit is trimmed above 5.1A to ensure adequate output current and controlled short-circuit current. On-chip thermal limiting provides protection against any combination of overload that would create excessive junction temperatures. The LX8554 series products are available in both through-hole and surfacemount versions of industry standard 3-pin TO-220 / TO-263 power packages. The LX8554 family of products are ideal for use in multiple processor applications where output voltage is jumper selected. The LX8554 ICs offer precision output as well as low supply operation (see application below). For higher current applications see the LX8584 series of products.
K E Y F E AT U R E S
s THREE-TERMINAL ADJUSTABLE OR FIXED OUTPUT s GUARANTEED ≤ 1V HEADROOM AT 5A s OUTPUT CURRENT OF 5A p FAST TRANSIENT RESPONSE p 1% VOLTAGE REFERENCE INITIAL ACCURACY p OUTPUT SHORT-CIRCUIT PROTECTION p BUILT-IN THERMAL SHUTDOWN s EVALUATION BOARD AVAILABLE: REQUEST LXE9001 EVALUATION KIT
A P P L I C AT I O N S
s s s s s s PENTIUM PROCESSOR SUPPLIES POWER PC SUPPLIES MICROPROCESSOR SUPPLIES LOW VOLTAGE LOGIC SUPPLIES BATTERY POWERED CIRCUIT POST REGULATOR FOR SWITCHING SUPPLY
PRODUCT HIGHLIGHT
TYPICAL APPLICATION OF THE LX8554 IN A FLEXIBLE MOTHERBOARD WITH OUTPUT VOLTAGE SELECTABLE VIA JUMPERS "JP1" AND "JP2"
VIN ³ 4.75
1500µF, 6.3V Sanyo MVGX Series
IN
LX8554
ADJ
OUT VREF
R1 121W 1%
(See Table Below)
VO
A VA I L A B L E O P T I O N S
Part #
LX8554-00 LX8554-33
PER
PAR T #
200W 1% R2
13W 1% 14.7W 1%
3x 1500µF 6.3V Sanyo MVGX Series
Output Voltage
Adjustable 3.3V
Other voltage options may be available — Please contact factory for details.
JP1 JP2
VOUT = VREF 1 + R2 + IADJ R2 R1
JP1 Open Open Short
JP2 Open Short Short
OUTPUT VOLTAGE 3.6V 3.45V 3.3V
PA C K A G E O R D E R I N F O R M AT I O N TA (°C) 0 to 125
TO-220 P Plastic 3-pin
LX8554-xxCP
T0-263 DD Plastic 3-pin
LX8554-xxCDD
Note: All surface-mount packages are available in Tape & Reel. Append the letter "T" to part number. (i.e. LX8554-00CDDT) "xx" refers to output voltage, please see table above.
F O R F U R T H E R I N F O R M AT I O N C A L L ( 7 1 4 ) 8 9 8 - 8 1 2 1
Copyright © 1997 Rev. 1.1 1/97
11861 WESTERN A VENUE , G ARDEN G ROVE , CA. 92841
1
PRODUCT DATABOOK 1996/1997
LX8554-xx
5A E XTREMELY L OW D ROPOUT P OSITIVE R EGULATORS
P
R O D U C T I O N
D
A T A
S
H E E T
A B S O L U T E M A X I M U M R AT I N G S
(Note 1)
PACKAGE PIN OUTS
TAB IS V OUT
3 2 1
Power Dissipation .................................................................................. Internally Limited Input Voltage ................................................................................................................ 10V Input to Output Voltage Differential ........................................................................... 10V Operating Junction Temperature Plastic (P Package) ................................................................................................ 150°C Storage Temperature Range ...................................................................... -65°C to 150°C Lead Temperature (Soldering, 10 seconds) ............................................................. 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.
VIN VOUT ADJ / GND*
P PACKAGE (Top View)
* Pin 1 is GND for fixed voltage versions. TAB IS V OUT
T H E R MAL DATA
P PACKAGE: THERMAL RESISTANCE-JUNCTION TO TAB, θJT THERMAL RESISTANCE-JUNCTION TO AMBIENT, θ JA DD PACKAGE: THERMAL RESISTANCE-JUNCTION TO TAB, θJT THERMAL RESISTANCE-JUNCTION TO AMBIENT, θ JA 2.7°C/W 60°C/W * 2.7°C/W 60°C/W
3 2 1
VIN VOUT ADJ / GND*
DD PACKAGE (Top View)
* Pin 1 is GND for fixed voltage versions.
Junction Temperature Calculation: TJ = TA + (PD x θJA). The θ JA numbers are guidelines for the thermal performance of the device/pc-board system. All of the above assume no ambient airflow. * θ JAcan be improved with package soldered to 0.5IN2 copper area over backside ground plane or internal power plane. θJAcan vary from 20ºC/W to > 40ºC/W depending on mounting technique.
2
Copyright © 1997 Rev. 1.1 1/97
PRODUCT DATABOOK 1996/1997
LX8554-xx
5A E XTREMELY L OW D.