LX1912 Datasheet, PDF (1/8 Pages) Microsemi Corporation – VREF @ 800mV, 1.0A, 1.2MHz PWM Current Mode PWM Buck regulator

LX1912
TM
®
VREF @ 800mV, 1.0A, 1.2MHz PWM
PRODUCTION DATA SHEET
DESCRIPTION
The LX1912 operates as a Current
Mode PWM Buck regulator that
switches to PFM mode with light
loads. The entire regulator function is
implemented with few external
components.
The LX1912 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 1.0A, 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 low regulator IQ and
PFM mode of operation
The LX1912 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 TSOT package provides a
small form factor with excellent power
dissipation capability.
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 90%
of V_IN
ƒ Output Current up to 1.0A
ƒ Quiescent Current < 550μA,
Typical @ 23°C
ƒ 1.2MHz PWM Frequency
ƒ Over Voltage Protection
APPLICATIONS
ƒ Portable Microprocessor Core
Voltage Supplies
ƒ 5V to 3V
ƒ RoHS Compliant Product
4V to 6V
4.7µF
VPWR _SW
VCC
LXP1a9rt12
GND
FB
N.C.
PRODUCT HIGHLIGHT
2.7µH
31.6K
3.3V @ 1.0A
30µF
10K
EFFICIENCY (VIN = 5V, VOUT @ 3.3V)
95%
90%
85%
80%
75%
70%
65%
60%
55%
50%
0.01
0.10
1.00
OUTPUT CURRENT (Amps)
Figure 1 – LX1912 Circuit Topology and Typical Efficiency Performance
T_A (°C)
0 to +70
PACKAGE ORDER INFO
Output
Input Voltage Voltage
Range
Plastic TSOT
SG _6-Pin
RoHS Compliant / Pb-free
4.0V – 6.0V Adjustable
LX1912CSG
Part Marking
1912
Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1912CSG-TR)
Copyright © 2005
Rev. 1.0, 2006-09-06
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: [phone]
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