DESCRIPTION KEY FEATURES
■■
■■
■Low Dropout, 800mV Max. at 7A
Output Current in Dual Supply Mode
■■
■■
■Fast Transient Response
■■
■■
■Remote Sensing
!1mV Load Regulation
!Adjustable Output
!No Supply Sequencing Problems in Dual
Supply Mode
The LX8580 is a high-performance, very
low dropout voltage regulator, designed for
use with advanced microprocessors. This
product can be used with separate voltage
supplies for the control and power sections,
allowing a power section dropout voltage
as low as 100mV. The LX8580 can also be
used in a single voltage supply configuration,
with a dropout performance similar to that
of the LX8584 (1.3V at 7A).
The LX8580 is supplied in a five-
terminal TO-220 package, which allows the
APPLICATIONS
■Microprocessor Supplies
■3.3V to 2.5V Processor Power Supplies
■High-Current Regulators
■Post Regulators for Switching Supplies
7A V
ERY
L
OW
D
ROPOUT
P
OSITIVE
A
DJUSTABLE
R
EGULATOR
PRODUCTION DATA SHEET
THE INFINITE POWER OF INNOVATION
LX8580
PACKAGE ORDER INFORMATION
TA (°C) Plastic TO-220
5-pin
P
0 to 125 0.1V - 0.8V LX8580-00CP LX8580-00CDD
Dropout
Voltage
PRODUCT HIGHLIGHT
R
A
LOAD
5
ADJUST
1
43
V
CTRL
³ V
OUT
+ 1.3V Max
V
PWR
³ V
OUT
+ V
DROPOUT
R
B
LX8580
V
OU
T
VCTRL
VPWR
2
SENSE
OUTPUT
SPECIAL CAPABILITIES OF THE LX8580 TO ALLOW 44%
SMALLER LDO THERMAL DISSIPATION
implementation of remote (Kelvin) voltage
sensing. This sensing compensates for
output voltage variations due to load
changes and resistive voltage drops in
connectors and board traces. Typical load
regulation measured at the sense pin is less
than 1mV for a load current step of 7mA
to 7A.
The LX8580 is ideal for generating a
secondary 2 - 2.5V low voltage supply on a
motherboard where a 3.3V supply is already
available.
NOTE: For current data & package dimensions, visit our web site: http://www.linfinity.com.
Copyright © 1999
Rev. 1.0 11/99 1
11861 WESTERN A VENUE, GARDEN G ROVE, CA. 92841, 714-898-8121, FAX: 714-893-2570
LINFINITY MICROELECTRONICS INC.
VOUT = VREF 1 + + IADJ x RB
RB
RA
Plastic TO-263
5-pin
DD
7A V
ERY
L
OW
D
ROPOUT
P
OSITIVE
A
DJUSTABLE
R
EGULATOR
LX8580
PRODUCT DATABOOK 1996/1997
2
PRODUCTION DATA SHEET
Copyright © 1999
Rev. 1.0 11/99
ABSOLUTE MAXIMUM RATINGS (Note 1)
Power Dissipation ...................................................................................... Internally Limited
VPWR Input Voltage ........................................................................................................... 7V
VCTRL Input Voltage ......................................................................................................... 13V
Operating Junction Temperature
Plastic (P Package) ................................................................................................ 150°C
Storage Temperature Range ...................................................................... -65°C to 150°C
Lead Temperature (Soldering, 10 seconds) ............................................................. 300°C
PACKAGE PIN OUTS
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.
BLOCK DIAGRAM
Current
Limiting
Amplifier
Thermal Overload
Voltage
Regulation
Amplifier
Power
OUTPUT
SENSE
ADJUST
V
REF
Control
V
CTRL
V
PWR
VPWR
VCTRL
OUTPUT
ADJUST
SENSE
P PACKAGE
(Top View)
1
5
TAB IS OUTPUT
DD PACKAGE
(Top View)
VPWR
VCTRL
OUTPUT
ADJUST
SENSE
3
2
1
4
5
TAB IS OUTPUT
P PACKAGE:
THERMAL RESISTANCE-JUNCTION TO TAB, θθ
θθ
θJT 3.0°C/W
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θθ
θθ
θJA 60°C/W
DD PACKAGE:
THERMAL RESISTANCE-JUNCTION TO TAB, θθ
θθ
θJT 3.0°C/W
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θθ
θθ
θJA 60°C/W
Junction Temperature Calculation: TJ = TA + (PD x θJA).
The θJA numbers are guidelines for the thermal performance of the device/pc-board system.
All of the above assume no ambient airflow.
THERMAL DATA
7A V
ERY
L
OW
D
ROPOUT
P
OSITIVE
A
DJUSTABLE
R
EGULATOR
LX8580
PRODUCT DATABOOK 1996/1997
3
Copyright © 1999
Rev. 1.0 11/99
PRODUCTION DATA SHEET
Reference Voltage VREF VCTRL = 2.75V, VPWR = 2V, ILOAD = 10mA, TJ = 25°C
VCTRL
= 2.7V to 6V,
VPWR
= 1.75V to 5.5V, I
OUT
= 10mA to 4A
VCTRL
= 2.7V to 6V,
VPWR
= 2.05V to 5.5V, I
OUT
= 10mA to 7A
Line Regulation ∆VREF (VIN)
V
CTRL
= 2.5V to 12V, V
PWR
= 1.75V to 5.5V, I
LOAD
= 10mA, T
J
= 25°C
V
CTRL
= 2.5V to 12V, V
PWR
= 1.75V to 5.5V, I
LOAD
= 10mA
Load Regulation
∆V
REF
(I
OUT
)
VCTRL = 2.75V, VPWR = 2.1V, ILOAD = 10mA to 7A (VADJ = 0)
Thermal Regulation ∆VOUT (Pwr) 30ms Pulse
Thermal Resistance RθJT Control Circuitry/Power Transistor
Ripple Rejection VCTRL = VPWR = 3.75V Avg, VRIPPLE = 1VP-P, VADJ = 0V, IOUT = 4A
Control Pin Current (Note 3) ICTRL VCTRL = 2.75V, VPWR = 2.05V, ILOAD = 100mA
VCTRL = 2.75V, VPWR = 2.05V, ILOAD = 4A
VCTRL = 2.75V, VPWR = 1.75V, ILOAD = 4A
VCTRL = 2.75V, VPWR = 2.05V, ILOAD = 7A
Adjust Pin Current IADJ VCTRL = 2.75V, VPWR = 2.05V, ILOAD = 0mA (VADJ = 0)
Current Limit Iθ(MAX) VCTRL = 2.75V, VPWR = 2.05V, ∆VOUT = 100mV (VADJ = 0)
Dropout Voltage (Control Section) VCTRL - VOUT VPWR = 2.05V, ILOAD = 100mA
Minimum VCTRL (Note 2) VPWR = 2.05V, ILOAD = 1A
(VPWR - VOUT)V
PWR = 2.05V, ILOAD = 2.75A
VPWR = 2.05V, ILOAD = 4A
VPWR = 2.05V, ILOAD = 7A
Dropout Voltage (Power Section) VPWR - VOUT VCTRL = 2.75V, ILOAD = 100mA
Minimum VPWR (Note 2) VCTRL = 2.75V, ILOAD = 1A
(VPWR - VOUT)V
CTRL = 2.75V, ILOAD = 2.75A
(VADJ = 0) VCTRL = 2.75V, ILOAD = 4A, TJ = 25°C
VCTRL = 2.75V, ILOAD = 4A
VCTRL = 2.75V, ILOAD = 7A, TJ = 25°C
VCTRL = 2.75V, ILOAD = 7A
Minimum Load Current VCTRL = 5V, VPWR = 3.3V, VADJ = 0V
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, these specifications apply over the operating ambient temperatures 0°C ≤ TA ≤ 125°C. Low duty cycle pulse testing
techniques are used which maintains junction and case temperatures equal to the ambient temperature.)
Parameter
Symbol
Test Conditions Units
LX8580
Min. Typ. Max.
1.243 1.250 1.257 V
1.237 1.250 1.263 V
1.237 1.250 1.263 V
13mV
26mV
27mV
0.002 0.020 %/W
0.65 2.70 °C/W
60 80 dB
310mA
30 60 mA
33 70 mA
60 120 mA
60 120 µA
7.1 9 A
0.90 1.15 V
1.00 1.15 V
1.05 1.18 V
1.06 1.20 V
1.10 1.30 V
0.05 0.17 V
0.10 0.22 V
0.20 0.38 V
0.30 0.40 V
0.30 0.50 V
0.52 0.62 V
0.56 0.80 V
510mA
Note 2. Dropout is caused by either minimum control voltage (VCTRL) or minimum power voltage (VPWR). Both parameters are specified with respect to
the output voltage. The specifications represent the minimum input/output voltage required to maintain 1% regulation.
Note 3. The control pin current is the drive current required for the output transistor. This current will track output current with roughly a 1:100 ratio.
The minimum value is equal to the quiescent current of the device.
7A V
ERY
L
OW
D
ROPOUT
P
OSITIVE
A
DJUSTABLE
R
EGULATOR
LX8580
PRODUCT DATABOOK 1996/1997
4
PRODUCTION DATA SHEET
Copyright © 1999
Rev. 1.0 11/99
SENSE 1
ADJUST 2
OUTPUT 3
VCTRL 4
VPWR 5
This pin is the positive side of the reference voltage for the device. With this pin it is possible to Kelvin-sense the output voltage
at load.
This pin is the negative side of the reference voltage for the device. Ripple rejection can be improved by adding a small bypass capacitor
from the Adjust pin to ground. The capacitor value should be selected so that CR ≤ 1 / 2πFRRA , where FR is the ripple frequency
and RA is the value of the resistor between the output and sense leads of the LX8580.
This is the power output of the device.
This pin is the voltage supply pin for the control circuitry of the device. The current flow into this pin will be about 1% of the output
current. For the device to regulate, the voltage at this pin must be between 1.0V and 1.3V greater than the output voltage.
This is the collector of the power section of the LX8580. The output load current is supplied through this pin. For the device to
regulate, the voltage at this pin must be between 0.1V and 0.8V greater than the output voltage (higher output currents require higher
voltages between VPWR and OUTPUT).
Pin # Description
FUNCTIONAL PIN DESCRIPTION
BASIC APPLICATION CIRCUIT
LX8580
LOAD
6000µF
(4X Sanyo 6mV 1500G
K
6.3V 1500µF)
5A
Tantalum
33µF 10V
5.0V
Tantalum
100µF
10V
V
OUT
= 2.775 2.89 (MAX)
2.67 (MIN)
1219
1%
1479
1%
V
PWR
V
CTRL
ADJUST
SYSTEM GROUND
0.259
"Electronic Heatsink"
Resistor reduces
thermal load
on LDO heatsink
to 6.9W
OUTPUT
SENSE
4 x 19 2W 5%
(Parallel Connected)
*Note
*Note: For improved transient response, add capacitor as shown (typical 15µF).
PRODUCTION DATA - Information contained in this document is proprietary to LinFinity, and is current as of publication date. This document
may not be modified in any way without the express written consent of LinFinity. Product processing does not necessarily include testing of all
parameters. Linfinity reserves the right to change the configuration and performance of the product and to discontinue product at any time.
