Switching Regulator. LT3503 Datasheet

LT3503 Regulator. Datasheet pdf. Equivalent

Part LT3503
Description 2.2MHz Step-Down Switching Regulator
Feature U U FEATURES ■ Wide Input Range: 3.6V to 20V ■ 5V at 1.2A from 11V to 18V Input ■ 5V at 1A from 7.2.
Manufacture Linear Technology
Datasheet
Download LT3503 Datasheet



LT3503
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
VIN
4.5V TO 12V
20V MAX
ON OFF
VIN BOOST
LT3503
SHDN
SW
GND FB
1µF
0.1µF 2.5µH
37.4k
11.5k
VOUT
3.3V
1A, VIN > 5.5V
1.2A, VIN > 8.5V
120pF
10µF
3503 TA01a
Efficiency
85
VIN = 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



LT3503
LT3503
ABSOLUTE AXI U RATI GS
(Note 1)
Input Voltage (VIN) .................................................. 20V
BOOST Pin Voltage .................................................. 40V
BOOST Pin Above SW Pin ....................................... 20V
SHDN Pin ................................................................ 20V
FB Voltage ................................................................. 6V
Operating Temperature Range (Note 2) ... –40°C to 85°C
Maximum Junction Temperature .......................... 125°C
Storage Temperature Range ................. – 65°C to 150°C
UW U
PACKAGE/ORDER I FOR ATIO
TOP VIEW
FB 1
6 SHDN
GND 2 7 5 VIN
BOOST 3
4 SW
DCB PACKAGE
6-LEAD (2mm ´ 3mm) PLASTIC DFN
TJMAX = 125°C, θJA = 64°C/ W
EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PCB
ORDER PART NUMBER DCB PART MARKING
LT3503EDCB
LCGW
Order Options Tape and Reel: Add #TR Lead Free: Add #PBF
Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
VIN = 12V, VBOOST = 17V, unless otherwise noted. (Note 2)
PARAMETER
VIN Operating Range
Undervoltage Lockout
Feedback Voltage
FB Pin Bias Current
Quiescent Current
Quiescent Current in Shutdown
Reference Line Regulation
Switching Frequency
Maximum Duty Cycle
CONDITIONS
VFB = Measured VREF (Note 4)
Not Switching
VSHDN = 0V
VIN = 5V to 20V
VFB = 0.7V
VFB = 0V
MIN TYP MAX
3.6 20
3.0 3.4 3.6
765 780 795
50 150
1.9 2.6
0.01 2
0.007
2.0 2.2 2.4
36
76
81
UNITS
V
V
mV
nA
mA
µA
%/V
MHz
kHz
%
3503f
2





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