LX1911 Datasheet, PDF (1/7 Pages) Microsemi Corporation – 1.5A, 1.1MHZ PWM Step-Down Regulator

LX1911
®
1.5A, 1.1MHZ PWM Step-Down Regulator
TM
PRODUCTION DATA SHEET
DESCRIPTION
The LX1911 operates as a Current
Mode PWM Buck regulator that
switches to PFM mode with light
loads. The entire regulator function
is implemented with minimal external
components.
The LX1911 responds quickly to
dynamic load changes using a high
bandwidth error amplifier and
internal compensation. Tight output
voltage regulation is maintained with
the compensated 800mV, ±2%
reference (line and temp regulation).
With two external resistors the output
voltage is easily programmed, from
800mV to 90% of V_IN.
The regulator is capable of providing
an output load current of 1.5A and has
no minimum load current requirement
for stable operation. Current limit is
cycle-by-cycle to protect the switch.
Power conversion efficiency is
maximized with a low regulator IQ and
PFM mode of operation.
The LX1911 operational range
covers 4.0V to 6.0V, features include
power on delay; soft start to limit
inrush currents; and thermal shutdown
during fault conditions.
The 6-pin package is a small, RoHS
compliant / Pb-free, MO-229 with
excellent power dissipation capacity.
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
KEY FEATURES
ƒ Internal Reference 800mv ±2%
Accuracy (Line and Temp.)
ƒ 4.0V to 6.0V Input Range
ƒ Internal Soft Start
ƒ Adj. Output From 0.8V to V_IN
ƒ Output Current (I >1.5A)
ƒ Quiescent Current < 550μA,
typical @ 23°C
ƒ 1.1MHz PWM Frequency
ƒ Micro Lead-frame, Thin MO-
229, 6-Pin Package
APPLICATIONS/BENEFITS
ƒ Portable Microprocessor Core
Voltage Supplies
ƒ 5V to 3V
PRODUCT HIGHLIGHT
4.0 to 6V
4.7µF
4
VIN_POWER
5
VIN_ANALOG
2
GND
LX1911
6
N.C.
3
SW
C
1
FB
10
C = 680p
100%
90%
80%
3.3µH
1.2V @ 1.5A
25K
20µF
50K
Ground
Range Tie-in
70%
60%
50%
40%
30%
1
EFFICIENCY vs I_OUT (V_IN=5V)
Top V_O=3.375V Lower V_O=1.25V
10
100
1000
10000
mA
Figure 1 – LX1911 Circuit Topology and Typical Efficiency Performance
T_A (°C)
PACKAGE ORDER INFO
Input Voltage
Output Voltage
Range
Plastic MO-229
LD _{6 Pin 3mm²}
RoHS Compliant / Pb-free
0 to 70
4.5V – 5.5V
Adjustable
LX1911CLD
For Tape & Reel, append the letters “TR” to the part number. (i.e. LX1911CLD-TR)
Part Markings
Copyright © 2004
Rev. 1.1, 2006-05-15
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: [phone]
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