LX1675 Datasheet, PDF (1/19 Pages) Microsemi Corporation – Multiple Output LoadSHARE™ PWM PRODUCTION DATA SHEET

LX1675
TM
®
Multiple Output LoadSHARE™ PWM
PRODUCTION DATA SHEET
DESCRIPTION
The LX1675 is a highly integrated High current MOSFETs can be directly
power supply controller IC featuring driven to provide an LDO output of 5A
three voltage mode PWM switching and 15A for each PWM controller. This
regulator stages with an additional is useful for I/O, memory, termination,
onboard linear regulator driver.
and other supplies surrounding today’s
Two of the constant frequency PWM micro-processor based designs.
phases can be easily configured for a The LX1675 accepts a wide range of
single Bi-Phase high current output or supply voltage ranging from 4.5V to 24V.
operated as two independently regulated Each PWM regulator output voltage is
outputs. All outputs (PWM phases and programmed via a simple voltage-divider
LDO) have separate, programmable soft- network. The LX1675 design gives
start sequencing. This versatility yields engineers maximum flexibility with
either three or four independently respect to the MOSFET supply. Each
regulated outputs with full power phase can utilize different supply voltages
sequencing capability giving system for efficient use of available supply rails.
designers the ultimate flexibility in power Additionally, when two phases are
supply design.
configured in Bi-Phase output, the
Current limit for each PWM regulator LoadSHARE^™ topology can be
is provided by monitoring the voltage programmed via inductor ESR selection.
drop across the lower MOSFET power The split phase operation reduces power
stage during conduction, utilizing the loss, noise due to the ESR of the input
Rds(on) impedance. This eliminates the capacitors and allows for reduction in
need for expensive current sense capacitance values while maximizing
resistors. Once current limit has been regulator response time. The internal
reached and persist for 4 clock cycles, the reference voltage is buffered and brought
output is shut off and Soft Start is out on a separate pin to be used as an
initialized to force a hiccup mode for external reference voltage.
protection.
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
LoadSHARE is a Trademark of Microsemi Corporation
Protected by U.S. Patents 6,285,571 and 6,292,378
VIN 4.5V to 24V
PRODUCT HIGHLIGHT
VOUT4
VCCL
VIN
VSLR
LDGD
LDFB
SSX
LX1675
AGND
EOX
HOX
VCX
HRX
CSX
LOX
PGX
FBX
5µh
VOUT1, 2, 3
KEY FEATURES
ƒ Four Independently Regulated
Outputs
ƒ Single Input Supply with Wide
Voltage Range: 4.5-24V
ƒ Outputs As Low As 0.8V
Generated From a Precision
Internal Reference
ƒ Selectable PWM Frequency of
300KHz or 600KHz
ƒ Buffered Reference Voltage
Output
ƒ Multiphase Output Reduces
Need for Large Input
Capacitance at High Currents
ƒ Integrated High Current
MOSFET Drivers
ƒ Independent Soft-Start and
Power Sequencing
ƒ Adjustable Linear Regulator
Driver Output
ƒ No Current-Sense Resistors
ƒ DDR Termination Compliant
ƒ RoHS Compliant for Pb Free
APPLICATIONS
ƒ Multi-Output Power Supplies
ƒ Video Card Power Supplies
ƒ PC Peripherals
ƒ Portable PC Processor and I/O
Supply
PACKAGE ORDER INFO
T_A (°C)
Plastic MLPQ
LQ _38-Pin
RoHS Compliant / Pb-free
0 to 85
LX1675CLQ
-40 to 85
LX1675ILQ
Note: Available in Tape & Reel. Append the
letters “TR” to the part number. (i.e.
LX1675CLQ-TR)
ONE OF 3 PWM SECTIONS
Copyright © 2004
Rev. 1.2a, 2006-02-16
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: [phone]
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