LT1936
1.4A, 500kHz Step-Down
Switching Regulator
FEATURES DESCRIPTION
Wide Input Range: 3.6V to 36V
The LT 1936 is a current mode PWM step-down DC/DC
Short-Circuit Protected Over Full Input Range
converter with an internal 1.9A power switch, packaged
1.9A Guaranteed Minimum Switch Current
in a tiny, thermally enhanced 8-lead MSOP. The wide in-
5V at 1.4A from 10V to 36V Input
put range of 3.6V to 36V makes the LT1936 suitable for
3.3V at 1.4A from 7V to 36V Input
regulating power from a wide variety of sources, including
5V at 1.2A from 6.3V to 36V Input
automotive batteries, 24V industrial supplies and unregu-
3.3V at 1.2A from 4.5V to 36V Input
lated wall adapters. Its high operating frequency allows the
Output Adjustable Down to 1.20V
use of small, low cost inductors and ceramic capacitors,
500kHz Fixed Frequency Operation
resulting in low, predictable output ripple.
Soft-Start
Cycle-by-cycle current limit, frequency foldback and
Uses Small Ceramic Capacitors
thermal shutdown provide protection against shorted
Internal or External Compensation
outputs, and soft-start eliminates input current surge
Low Shutdown Current: <2A
during start-up. Transient response can be optimized by
Thermally Enhanced 8-Lead MSOP Package
using external compensation components, or board space
can be minimized by using internal compensation. The
low current (<2A) shutdown mode enables easy power
APPLICATIONS
management in battery-powered systems.
Automotive Battery Regulation
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other
Industrial Control Supplies
trademarks are the property of their respective owners.
Unregulated Wall Adapters
TYPICAL APPLICATION
3.3V Step-Down Converter Ef ciency
95
V = 12V
IN
V
IN
4.5V TO 36V
V = 5V
OUT
90
0.22F
V BOOST
IN
10H
V
OUT
ON OFF SHDN SW 3.3V 85
1.2A
V = 3.3V
OUT
LT1936
4.7F
17.4k 80
COMP FB
V
GND 75
C
10k
22F
70
1936 TA01a
65
0 0.5 1 1.5
LOAD CURRENT (A)
1936 TA01b
1936fd
1
EFFICIENCY (%)LT1936
ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION
(Note 1)
V Voltage ................................................. 0.4V to 36V
IN
TOP VIEW
BOOST Voltage .........................................................43V
BOOST 1 8 COMP
BOOST Above SW Voltage ........................................20V V 2 7 V
IN C
9
6 FB
SW 3
SHDN Voltage ............................................ 0.4V to 36V
GND 4 5 SHDN
FB, V , COMP Voltage .................................................6V
C
MS8E PACKAGE
8-LEAD PLASTIC MSOP
Operating Temperature Range (Note 2)
= 40C/W, = 10C/W
JA JC
LT1936E ............................................... 40C to 85C EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
LT1936I .............................................. 40C to 125C
LT1936H ............................................ 40C to 150C
Maximum Junction Temperature
LT1936E, LT1936I ............................................. 125C
LT1936H ........................................................... 150C
Storage Temperature Range ................... 65C to 150C
Lead Temperature (Soldering, 10 sec) .................. 300C
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LT1936EMS8E#PBF LT1936EMS8E#TRPBF LTBMT 8-Lead Plastic MSOP 40C to 85C
LT1936IMS8E#PBF LT1936IMS8E#TRPBF LTBRV 8-Lead Plastic MSOP 40C to 125C
LT1936HMS8E#PBF LT1936HMS8E#TRPBF LTBWB 8-Lead Plastic MSOP 40C to 150C
LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LT1936EMS8E LT1936EMS8E#TR LTBMT 8-Lead Plastic MSOP 40C to 85C
LT1936IMS8E LT1936IMS8E#TR LTBRV 8-Lead Plastic MSOP 40C to 125C
LT1936HMS8E LT1936HMS8E#TR LTBWB 8-Lead Plastic MSOP 40C to 150C
Consult LTC Marketing for parts speci ed with wider operating temperature ranges.
For more information on lead free part marking, go to: