LT3503_15 Datasheet, PDF (1/20 Pages) Linear Technology – 1A, 2.2MHz Step-Down Switching Regulator

FEATURES
■ _{Wide Input Range: 3.6V to 20V}
■ _{5V at 1.2A from 11V to 18V Input}
■ _{5V at 1A from 7.2V to 18V Input}
■ _{3.3V at 1.2A from 8.5V to 12V Input}
■ _{3.3V at 1A from 5.5V to 12V Input}
■ _{Fixed Frequency Operation: 2.2MHz}
■ _{Output Adjustable Down to 780mV}
■ _{Short-Circuit Robust}
■ _{Uses Tiny Capacitors and Inductors}
■ _Soft-Start
■ _{Internally Compensated}
■ _{Low Shutdown Current: <2µA}
■ _{Low VCESAT Switch: 400mV at 1A}
■ _{Thermally Enhanced, 2mm × 3mm 6-Pin DFN}
Low Profile Package
U
APPLICATIO S
■ _{Automotive Battery Regulation}
■ _{Industrial Control Supplies}
■ _{Wall Transformer Regulation}
■ _{Distributed Supply Regulation}
■ _{Battery-Powered Equipment}
LT3503
1A, 2.2MHz Step-Down
Switching Regulator in
2mm × 3mm DFN
DESCRIPTIO
The LT^®3503 is a current mode PWM step-down DC/DC
converter with an internal 1.45A power switch. The wide
operating input range of 3.6V to 20V makes the LT3503
ideal for regulating power from a wide variety of sources.
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
mode provides output disconnect, enabling easy power
management in battery-powered systems.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
3.3V Step-Down Converter
V_IN
4.5V TO 12V
20V MAX
ON OFF
V_IN
BOOST
LT3503
SHDN
SW
GND FB
1µF
0.1µF _2.5µH
37.4k
11.5k
V_OUT
3.3V
1A, V_IN > 5.5V
1.2A, V_IN > 8.5V
120pF
10µF
3503 TA01a
Efficiency
85
V_IN = 12V
80
75
70
65
60
55
50
0 0.2 0.4 0.6 0.8 1.0 1.2
LOAD CURRENT (A)
3503 TA01b
3503f
1