POWER LOSS (mW)
LTC3631
High Efficiency, High Voltage
100mA Synchronous
Step-Down Converter
FeaT DescripT
n
Wide Input Voltage Range: Operation from 4.5V to 45V The LTC 3631 is a high voltage, high efficiency step-down
n
Overvoltage Lockout Provides Protection Up to 60V DC/DC converter with internal high side and synchronous
n
Internal High Side and Low Side Power Switches power switches that draws only 12A typical DC supply
n
No Compensation Required current at no load while maintaining output voltage
n
100mA Output Current regulation.
n
Low Dropout Operation: 100% Duty Cycle
The LTC3631 can supply up to 100mA load current and
n
Low Quiescent Current: 12A
features a programmable peak current limit that provides
n
0.8V 1% Feedback Voltage Reference
a simple method for optimizing efficiency in lower current
n
Adjustable Peak Current Limit
applications. The LTC3631s combination of Burst Mode
n
Internal and External Soft-Start
operation, integrated power switches, low quiescent cur-
n
Precise RUN Pin Threshold with Adjustable
rent, and programmable peak current limit provides high
Hysteresis
efficiency over a broad range of load currents.
n
3.3V, 5V and Adjustable Output Versions
n With its wide 4.5V to 45V input range and internal overvolt-
Only Three External Components Required for Fixed
age monitor capable of protecting the part from 60V surges,
Output Versions
n the LTC3631 is a robust converter suited for regulating a
Low Profile (0.75mm) 3mm 3mm DFN and
wide variety of power sources. Additionally, the LTC3631
Thermally-Enhanced MS8E Packages
includes a precise run threshold and a soft-start feature
to guarantee that power system start-up is well-controlled
Ta
in any environment.
n
4mA to 20mA Current Loops
The LTC3631 is available in the thermally enhanced
n
Industrial Control Supplies
3mm 3mm DFN and MS8E packages.
n
Distributed Power Systems
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
n
Portable Instruments
and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the
n property of their respective owners.
Battery-Operated Devices
n
Automotive Power Systems
Efficiency and Power Loss vs Load Current
Typical Ta
100
EFFICIENCY
90 1000
5V, 100mA Step-Down Converter
80
100H
V
OUT
V 70 100
IN
V SW 5V
IN
5V TO 45V
100mA
LTC3631-5
2.2F 10F
60
RUN V POWER LOSS
OUT
50 10
HYST SS
I
SET
40
GND
30 1
V = 12V
IN
3631 TA01a
V = 36V
IN
20
0.1 1 10 100
LOAD CURRENT (mA)
3631 TA01b
3631fe
1
For more information www.linear.com/LTC3631
EFFICIENCY (%)
ion pplica
ions pplica
ion uresLTC3631
Ta e MaxiMMu Tar (Note 1)
V Supply Voltage ..................................... 0.3V to 60V Operating Junction Temperature Range
IN
SW Voltage (DC) ........................... 0.3V to (V + 0.3V) (Note 2) .................................................. 40C to 125C
IN
RUN Voltage .............................................. 0.3V to 60V Storage Temperature Range ................... 65C to 150C
HYST, I , SS Voltages ............................... 0.3V to 6V Lead Temperature (Soldering, 10 sec)
SET
V ............................................................... 0.3V to 6V MS8E ................................................................ 300C
FB
V (Fixed Output Versions) ....................... 0.3V to 6V
OUT
in p Fc T
TOP VIEW
TOP VIEW
SW 1 8 GND
SW 1 8 GND
V 2 7 HYST
IN 9
V 2 9 7 HYST
IN
GND
GND
I 3 6 V /V I V /V
SET OUT FB 3 6
SET OUT FB
SS 4 5 RUN
SS RUN
4 5
MS8E PACKAGE
8-LEAD PLASTIC MSOP
DD PACKAGE
T = 125C, = 40C/W, = 5-10C/W
JMAX JA JC
8-LEAD (3mm 3mm) PLASTIC DFN
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
T = 125C, = 43C/W, = 3C/W
JMAX JA JC
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
LTC3631EMS8E#PBF LTC3631EMS8E#TRPBF LTFDT 8-Lead Plastic MSOP 40C to 125C
LTC3631EMS8E-3.3#PBF LTC3631EMS8E-3.3#TRPBF LTFFP 8-Lead Plastic MSOP 40C to 125C
LTC3631EMS8E-5#PBF LTC3631EMS8E-5#TRPBF LTFFR 8-Lead Plastic MSOP 40C to 125C
LTC3631IMS8E#PBF LTC3631IMS8E#TRPBF LTFDT 8-Lead Plastic MSOP 40C to 125C
LTC3631IMS8E-3.3#PBF LTC3631IMS8E-3.3#TRPBF LTFFP 8-Lead Plastic MSOP 40C to 125C
LTC3631IMS8E-5#PBF LTC3631IMS8E-5#TRPBF LTFFR 8-Lead Plastic MSOP 40C to 125C
LTC3631EDD#PBF LTC3631EDD#TRPBF LFDV 8-Lead (3mm 3mm) Plastic DFN 40C to 125C
LTC3631EDD-3.3#PBF LTC3631EDD-3.3#TRPBF LFFN 40C to 125C
8-Lead (3mm 3mm) Plastic DFN
LTC3631EDD-5#PBF LTC3631EDD-5#TRPBF LFFQ 8-Lead (3mm 3mm) Plastic DFN 40C to 125C
LTC3631IDD#PBF LTC3631IDD#TRPBF LFDV 8-Lead (3mm 3mm) Plastic DFN 40C to 125C
LTC3631IDD-3.3#PBF LTC3631IDD-3.3#TRPBF LFFN 8-Lead (3mm 3mm) Plastic DFN 40C to 125C
LTC3631IDD-5#PBF LTC3631IDD-5#TRPBF LFFQ 40C to 125C
8-Lead (3mm 3mm) Plastic DFN
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: