LT1933_1 Datasheet, PDF (1/20 Pages) Linear Technology – 600mA, 500kHz Step-Down Switching Regulator in SOT-23 and DFN Packages

FEATURES
n _{Wide Input Range: 3.6V to 36V}
n _{5V at 600mA from 16V to 36V Input}
n _{3.3V at 600mA from 12V to 36V Input}
n _{5V at 500mA from 6.3V to 36V Input}
n _{3.3V at 500mA from 4.5V to 36V Input}
n _{Fixed Frequency 500kHz Operation}
n _{Uses Tiny Capacitors and Inductors}
n _Soft-Start
n _{Internally Compensated}
n _{Low Shutdown Current: <2μA}
n _{Output Adjustable Down to 1.25V}
n _{Low Profile (1mm) SOT-23 (ThinSOT™) and}
(2mm x 3mm x 0.75mm) 6-Pin DFN Packages
APPLICATIONS
n _{Automotive Battery Regulation}
n _{Industrial Control Supplies}
n _{Wall Transformer Regulation}
n _{Distributed Supply Regulation}
n _{Battery-Powered Equipment}
LT1933
600mA, 500kHz Step-Down
Switching Regulator in SOT-
23 and DFN Packages
DESCRIPTION
The LT^®1933 is a current mode PWM step-down DC/DC
converter with an internal 0.75A power switch, packaged
in a tiny 6-lead SOT-23. The wide input range of 3.6V
to 36V makes the LT1933 suitable for regulating power
from a wide variety of sources, including unregulated wall
transformers, 24V industrial supplies and automotive
batteries. Its high operating frequency allows the use of
tiny, low cost inductors and ceramic capacitors, resulting
in low, predictable output ripple.
Cycle-by-cycle current limit provides protection against
shorted outputs, and soft-start eliminates input current
surge during start up. The low current (<2μA) shutdown
provides output disconnect, enabling easy power manage-
ment in battery-powered systems.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ThinSOT is
a trademark of Linear Technology Corporation. All other trademarks are the property of their
respective owners.
TYPICAL APPLICATION
V_IN
4.5V TO 36V
OFF ON
3.3V Step-Down Converter
V_IN
BOOST
LT1933
SHDN
SW
GND
FB
16.5k
1N4148
0.1μF
22μH
MBRM140
2.2μF
10k
V_OUT
3.3V/500mA
22μF
1933 TA01a
Efficiency
95 _{VIN = 12V}
90
V_OUT = 5V
85
V_OUT = 3.3V
80
75
70
65
0 100 200 300 400 500 600
LOAD CURRENT (mA)
1933 TA01b
1933fd
1