POWER LOSS (W)
LTC3803-5
Constant Frequency
Current Mode Flyback
DC/DC Controller in ThinSOT
FEATURES DESCRIPTION
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V and V Limited Only by External Components
The LTC 3803-5 is a constant frequency current mode
IN OUT
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4.8V Undervoltage Lockout Threshold
yback controller optimized for driving N-channel MOSFETs
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Operating Junction Temperature from 55C to
in high input voltage applications. The LTC3803-5 operates
150C
from inputs as low as 5V. Constant frequency operation
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Adjustable Slope Compensation
is maintained down to very light loads, resulting in less
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Internal Soft-Start
low frequency noise generation over a wide range of load
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Constant Frequency 200kHz Operation
currents. Slope compensation can be programmed with
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1.5% Reference Accuracy
an external resistor.
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Current Mode Operation for Excellent Line and Load
The LTC3803-5 provides 1.5% output voltage accuracy
Transient Response
and consumes only 240A of quiescent current. Ground-
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No Minimum Load Requirement
referenced current sensing allows LTC3803-5-based con-
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Low Quiescent Current: 240A
verters to accept input supplies beyond the LTC3803-5s
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Low Pro le (1mm) SOT-23 Package
absolute maximum V . For simplicity, the LTC3803-5 can
CC
be powered from a high V through a resistor, due to its
IN
internal shunt regulator. An internal undervoltage lockout
APPLICATIONS
shuts down the IC when the input voltage is too low to
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42V and 12V Automotive Power Supplies
provide suf cient gate drive to the external MOSFET.
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Telecom Power Supplies
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Auxiliary/Housekeeping Power Supplies
The LTC3803-5 is available in a low pro le (1mm) 6-lead
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Power Over Ethernet
SOT-23 (ThinSOT) package.
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
and ThinSOT and No R are trademarks of Linear Technology Corporation. All other
SENSE
trademarks are the property of their respective owners.
TYPICAL APPLICATION
Ef ciency and Power Loss
Dual Output Wide Input Range Converter
vs Output Power
10MQ100N
VPH5-0155
V 13V/0.3A
IN
90 3.0
V = 8V
6V TO 50V 20mA MIN IN
1F
LOAD
100V
22k
85 2.5
PDZ6.8B 3 V = 12V
IN
22F
10V
MMBTA42
80 2.0
1F
V = 24V
IN
10nF PHM25NQ10T 100V
LTC3803-5
7.5k
75 1.5
1F
I /RUN NGATE
TH
100V
GND V 6.5V/1.2A
CC
70 1.0
4.7k
V SENSE
FB B3100 V = 48V
47F IN
8.06k
10V
0.012
65 0.5
0.1F
V = 12V
IN
57.6k
60 0
02 4 68 10 12
ALL CAPACITORS ARE X7R, TDK
OUTPUT POWER (W)
38035 TA01
38035 TA01b
38035fd
1
EFFICIENCY (%)LTC3803-5
ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION
(Note 1)
V to GND (Current Fed) ..................... 25mA into V *
CC CC
NGATE Voltage .......................................... 0.3V to V
CC
TOP VIEW
V , I /RUN Voltages............................... 0.3V to 3.5V
FB TH
I /RUN 1 6 NGATE
SENSE Voltage ............................................ 0.3V to 1V
TH
GND 2 5 V
CC
NGATE Peak Output Current (<10s) ......................... 1A
V 3 4 SENSE
FB
Operating Junction Temperature Range (Notes 2, 3)
LTC3803E-5 ....................................... 40C to 125C
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
LTC3803I-5 ........................................ 40C to 125C
T = 150C, = 192C/W
JMAX JA
LTC3803H-5 (Note 3) ......................... 40C to 150C
LTC3803MP-5 (Note 3) ...................... 55C to 150C
Storage Temperature Range ...................65C to 150C
Lead Temperature (Soldering, 10 sec) .................. 300C
*LTC3803-5 internal clamp circuit self regulates V voltage to 8.1V.
CC
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3803ES6-5#PBF LTC3803ES6-5#TRPBF LTBPF 6-Lead Low Pro le (1mm) SOT-23 40C to 125C
LTC3803IS6-5#PBF LTC3803IS6-5#TRPBF LTBMH 6-Lead Low Pro le (1mm) SOT-23 40C to 125C
LTC3803HS6-5#PBF LTC3803HS6-5#TRPBF LTBMH 6-Lead Low Pro le (1mm) SOT-23 40C to 150C
LTC3803MPS6-5#PBF LTC3803MPS6-5#TRPBF LTBMH 6-Lead Low Pro le (1mm) SOT-23 55C to 150C
LEAD BASED FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3803ES6-5 LTC3803ES6-5#TR LTBPF 6-Lead Low Pro le (1mm) SOT-23 40C to 125C
LTC3803IS6-5 LTC3803IS6-5#TR LTBMH 6-Lead Low Pro le (1mm) SOT-23 40C to 125C
LTC3803HS6-5 LTC3803HS6-5#TR LTBMH 6-Lead Low Pro le (1mm) SOT-23 40C to 150C
LTC3803MPS6-5 LTC3803MPS6-5#TR LTBMH 6-Lead Low Pro le (1mm) SOT-23 55C to 150C
Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *The temperature grade is identi ed by a label on the shipping container.
For more information on lead free part marking, go to: