LT3663
1.2A Step-Down
Switching Regulator with
Output Current Limit
FeaT DescripT
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Wide Input Range:
The LT 3663 is a current mode step-down switching regu-
Operation from 7.5V to 36V
lator with programmable output current limit. The current
Overvoltage Lockout Protects Circuit through 60V
limit accurately controls the system power dissipation and
Transients
reduces the size of the power path components.
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Programmable Output Current Limit (0.4A to 1.2A)
The wide operating input voltage range of 7.5V to 36V (60V
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3.3V and 5V Fixed Output Voltage Options
transient) suits the LT3663 to a variety of input sources,
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Integrated Boost Diode
including unregulated 12V wall adapters, 24V industrial
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Fixed Frequency, Peak Current Mode Control
supplies, and automotive power.
LT3663 f = 1.5MHz
SW
The LT3663 includes a low current shutdown mode, input
LT3663-X f = 1MHZ
SW
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overvoltage and undervoltage lockout, and thermal shut-
Low Switch V : 275mV at 1A
CESAT
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down. Internal compensation and boost diode minimize the
Internally Compensated
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number of external exponents. 3.3V and 5V fixed output
Thermal Protection
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voltage versions are available.
Thermally Enhanced 8-Pin 2mm 3mm DFN and
MSOP Packages
The LT3663 is available in 8-lead DFN and MSOP packages
with exposed pads for low thermal resistance.
Ta L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
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Distributed Supply Regulation
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Automotive Battery Regulation
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Industrial Supplies
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Wall Transformer Regulation
Typical Ta
5V Step-Down Converter Efficiency
100
V V BOOST
IN IN
2.2F
90
0.1F
LT3663 V = 8V
IN
SW
V = 15V
80 IN
V = 30V
IN
RUN 6.8H
ON OFF
70
I
SENSE
60
I V V
LIM OUT OUT
28.7k 59k 22F
50
FB
GND 40
11k
0.1 0.3 0.5 0.7 0.9 1.1 1.3
3663 TA01
OUTPUT CURRENT (A)
3663 TA01b
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EFFICIENCY (%)
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Ta e MaxiMMu Tar
(Note 1)
Operating Junction Temperature Range (Note 3)
Input Voltage (V ) (Note 2) ......................................60V
IN
LT3663E ............................................. 40C to 125C
BOOST Pin Voltage ...................................................50V
LT3663I .............................................. 40C to 125C
BOOST Pin Above SW Pin .........................................25V
LT3663H ............................................ 40C to 150C
V , V , I , FB Pins .......................................6V
OUTS OUT SENSE
Storage Temperature .............................. 65C to 150C
RUN Pin (Note 2) ......................................................60V
in p Fc T
LT3663 LT3663-X
TOP VIEW TOP VIEW
8 V 1 8 SW
V 1 SW
IN IN
7 RUN 2 7 BOOST
RUN 2 BOOST
9 9
GND GND
FB 6 I V 3 6 I
3 OUTS SENSE
SENSE
I 5 V I 4 5 V
4 LIM OUT
LIM OUT
DCB PACKAGE
DCB PACKAGE
8-LEAD (2mm 3mm) PLASTIC DFN
8-LEAD (2mm 3mm) PLASTIC DFN
= 64C/W = 64C/W
JA
JA
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
LT3663 LT3663-X
TOP VIEW
TOP VIEW
V 1 8 SW
IN V 1 8 SW
IN
RUN 2 7 BOOST
9 7 BOOST
RUN 2 9
FB 3 GND 6 I
SENSE V 3 GND 6 I
SENSE
OUTS
I 4 5 V
5 V
LIM OUT I 4
LIM OUT
MSE PACKAGE
MSE PACKAGE
8-LEAD PLASTIC MSOP
8-LEAD PLASTIC MSOP
= 35C/W = 35C/W
JA JA
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
Der inFMTa
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LT3663EDCB#PBF LT3663EDCB#TRPBF LDVK 8-Lead (2mm 3mm) Plastic DFN 40C to 125C
LT3663IDCB#PBF LT3663IDCB#TRPBF LDVK 8-Lead (2mm 3mm) Plastic DFN 40C to 125C
LT3663EDCB-3.3#PBF LT3663EDCB-3.3#TRPBF LFMW 8-Lead (2mm 3mm) Plastic DFN 40C to 125C
LT3663IDCB-3.3#PBF LT3663IDCB-3.3#TRPBF LFMW 40C to 125C
8-Lead (2mm 3mm) Plastic DFN
LT3663EDCB-5#PBF LT3663EDCB-5#TRPBF LFMY 8-Lead (2mm 3mm) Plastic DFN 40C to 125C
LT3663IDCB-5#PBF LT3663IDCB-5#TRPBF LFMY 8-Lead (2mm 3mm) Plastic DFN 40C to 125C
LT3663EMS8E#PBF LT3663EMS8E#TRPBF LTDWT 8-Lead Plastic MSOP 40C to 125C
LT3663IMS8E#PBF LT3663IMS8E#TRPBF LTDWT 8-Lead Plastic MSOP 40C to 125C
LT3663HMS8E#PBF LT3663HMS8E#TRPBF LTDWT 8-Lead Plastic MSOP 40C to 150C
LT3663EMS8E-3.3#PBF LT3663EMS8E-3.3#TRPBF LTFMX 8-Lead Plastic MSOP 40C to 125C
LT3663IMS8E-3.3#PBF LT3663IMS8E-3.3#TRPBF LTFMX 8-Lead Plastic MSOP 40C to 125C
LT3663HMS8E-3.3#PBF LT3663HMS8E-3.3#TRPBF LTFMX 8-Lead Plastic MSOP 40C to 150C
LT3663EMS8E-5#PBF LT3663EMS8E-5#TRPBF LTFMZ 8-Lead Plastic MSOP 40C to 125C
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For more information www.linear.com/LT3663
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