LX1911
TM
廬
1.5A, 1.1MH
Z
PWM Step-Down Regulator
P
RODUCTION
D
ATA
S
HEET
DESCRIPTION
KEY FEATURES
Internal Reference 800mv 鹵2%
Accuracy (Line and Temp.)
4.0V to 6.0V Input Range
Internal Soft Start
Adj. Output From 0.8V to V
IN
Output Current (I >1.5A)
Quiescent Current < 550渭A,
typical @ 23擄C
1.1MHz PWM Frequency
Micro Lead-frame, Thin MO-
229, 6-Pin Package
APPLICATIONS/BENEFITS
Portable Microprocessor Core
Voltage Supplies
5V to 3V
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, 鹵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.
WWW .
Microsemi
.C
OM
IMPORTANT:
For the most current data, consult
MICROSEMI鈥檚
website:
http://www.microsemi.com
PRODUCT HIGHLIGHT
EFFICIENCY vs I
OUT
(V
IN
=5V)
100%
4.0 to 6V
4
6
Top V
O
=3.375V
Lower V
O
=1.25V
90%
80%
3.3碌H
1.2V @ 1.5A
C
25K
20碌F
10
C = 680p
50K
Ground
Range Tie-in
1
VIN
POWER
5
N.C.
3
VIN
ANALOG
4.7碌F
2
SW
70%
60%
50%
40%
30%
1
10
100
mA
GND
FB
LX1911
1000
10000
Figure 1
鈥?LX1911 Circuit Topology and Typical Efficiency Performance
PACKAGE ORDER INFO
T
A
(擄C)
0 to 70
Input Voltage
4.5V 鈥?5.5V
Output Voltage
Range
Adjustable
LX1911
LX1911
LD
Plastic MO-229
6 Pin 3mm虜
LX1911CLD
RoHS Compliant / Pb-free
Part Markings
For Tape & Reel, append the letters 鈥淭R鈥?to the part number. (i.e. LX1911CLD-TR)
Copyright
漏
2004
Rev. 1.1, 2006-05-15
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
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