LX1918 Datasheet, PDF (1/9 Pages) Microsemi Corporation – 1.8A Step-Down Synchronous Converter

LX1918
TM
®
1.8A Step-Down Synchronous Converter
PRODUCTION DATA SHEET
DESCRIPTION
The Microsemi LX1918 is a step The LX1918 MODE feature can
down buck regulator with a either maximize efficiency or reduce
synchronous rectifier. All MOSFET EMI depending on the needs of the
switches and compensation com- application. High efficiency (MODE =
ponents are built in. The synchronous GND) is obtained by allowing the
rectification eliminates the need of an LX1918 to enter a PFM mode with
external Schottky diode and discontinuous inductor current. Low
maximizes efficiency (>95%) for a EMI (MODE=VCC) is obtained by
high step-down ratio and a low output only operating in PWM mode even at
voltage. The input supply voltage no load.
range is from 2.7V to 5.5V with a The LX1918 features include soft
maximum output current of 1.8A.
start, cycle-by-cycle switch current
The LX1918 is a current mode limit, hiccup short circuit current
PWM with optional PFM under light limiting and thermal shut down.
loads. The LX1918 can switch with a The LX1918 comes in small 8 pin
1MHz free running internal oscillator MLP package (fully RoHS compliant).
or be synchronized with an external
oscillator ranging from 500KHz to
1.25MHz; the high frequency allows
for small size and low cost external
components. The LX1918 output
voltage is programmable with two
resistors and can be tightly regulated
down to 0.6V.
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
PRODUCT HIGHLIGHT
V_IN
KEY FEATURES
ƒ Input range voltage 2.7 to 5.5V
ƒ Maximum output current, 1.8A
ƒ Internal or External
Synchronization
ƒ Output Voltage from V_IN to 0.6V
ƒ PFM or PWM mode under light
load
ƒ EMI support with force PWM
mode
ƒ Efficiency up to 95%
ƒ No external Schottky diode
ƒ Thermal shutdown
ƒ Cycle by cycle switch current
limit
ƒ UVLO
ƒ Short circuit protection
ƒ 8 pin MLP
APPLICATIONS
ƒ Lower power embedded
applications
ƒ WLAN power system
ƒ Portable design with single cell
Lion or 3 cells NiMH/NiCd
ƒ Low power portable storage
application
ON OFF
VCC ^PWR SW
MODE
LX1918
E/S
FB
PGND SGND
V_OUT @ 1.8 A
Copyright © 2004
Rev. 1.1, 2005-07-05
PACKAGE ORDER INFO
T_A (°C)
Plastic MLP
LD _{8-Pin 3x3mm}
RoHS Compliant / Pb-free
-40 to 85
LX1918CLD
Note: Available in Tape & Reel. Append the letters
“TR” to the part number.(i.e. LX1918CLD-TR)
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: [phone]
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