POWER LOSS (W)
LTC3621/LTC3621-2
17V, 1A Synchronous
Step-Down Regulator with
3.5A Quiescent Current
Fea T Descrip T
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Wide V Range: 2.7V to 17V The LTC 3621/LTC3621-2 is a high efficiency 17V, 1A
IN
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Wide V Range: 0.6V to V synchronous monolithic step-down regulator. The switch-
OUT IN
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ing frequency is fixed to 1MHz or 2.25MHz with a 40%
95% Max Efficiency
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synchronizing range. The regulator features ultralow quies-
Low I < 3.5A, Zero-Current Shutdown
Q
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cent current and high efficiencies over a wide V range.
Constant Frequency (1MHz/2.25MHz)
OUT
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Full Dropout Operation with Low I
Q
The step-down regulator operates from an input voltage
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1A Rated Output Current
range of 2.7V to 17V and provides an adjustable output
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1% Output Voltage Accuracy
range from 0.6V to V while delivering up to 1A of output
IN
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Current Mode Operation for Excellent Line and Load
current. A user-selectable mode input is provided to allow
Transient Response
the user to trade off ripple noise for light load efficiency;
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Synchronizable to External Clock
Burst Mode operation provides the highest efficiency at
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Pulse-Skipping, Forced Continuous, Burst Mode
light loads, while pulse-skipping mode provides the lowest
Operation
voltage ripple. The MODE pin can also be used to allow the
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Internal Compensation and Soft-Start
user to sync the switching frequency to an external clock.
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Overtemperature Protection
LTC3621 Options
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Compact 6-Lead DFN (2mm 3mm) Package or
PART NAME FREQUENCY V
OUT
Thermally-Enhanced MS8E Package with Power
LTC3621 1.00MHz Adjustable
Good Output and Independent SGND Pin
LTC3621-3.3 1.00MHz 3.3V
LTC3621-5 1.00MHz 5V
a T
LTC3621-2 2.25MHz Adjustable
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Portable-Handheld Scanners
LTC3621-23.3 2.25MHz 3.3V
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Industrial and Embedded Computing
LTC3621-25 2.25MHz 5V
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Automotive Applications
L, LT, LTC, LTM, Burst Mode, Linear Technology, the Linear logo and LTSpice are registered
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Emergency Radio
trademarks and Hot Swap and LTpowerCAD are trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S. Patents,
including 5481178, 6580258, 6498466, 6611131, 6177787, 5705919, 5847554.
Typical a T
Efficiency and Power Loss vs Load at 1MHz
100 0.6
2.5V V with 400mA Burst Clamp, f = 1MHz
OUT SW V = 12V
IN
90
4.7H 0.5
V
EFFICIENCY
OUT
V 80
IN
V SW 2.5V
IN
2.7V TO 17V
1A
70
10F 604k 22pF
LTC3621
0.4
60
RUN 22F
FB
MODE/SYNC
191k
3621 TA01a 50 0.3
INTV POWER LOSS
CC
40
GND
1F
0.2
30
20
V = 5V
OUT 0.1
V = 3.3V
OUT
10
V = 2.5V
OUT
0 0
0 0.2 0.4 0.6 0.8 1
LOAD CURRENT (A)
3621 TA01b
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For more information www.linear.com/LTC3621
EFFICIENCY (%)
ion pplica
ions pplica
ion uresLTC3621/LTC3621-2
a Te Maxi Mu M r a T (Note 1)
V Voltage ................................................. 17V to 0.3V Operating Junction Temperature Range (Notes 3, 6, 7)
IN
RUN Voltage................................................ V to 0.3V LTC3621E, LTC3621I .......................... 40C to 125C
IN
MODE/SYNC, FB Voltages ............................ 6V to 0.3V LTC3621H .......................................... 40C to 150C
PGOOD Voltages .......................................... 6V to 0.3V Storage Temperature Range .................. 65C to 150C
p in c F T
TOP VIEW
TOP VIEW
1 6 MODE/SYNC
SW
SW 1 8 SGND
7 V 2 9 7 MODE/SYNC
IN
5 INTV
V 2
IN CC
GND GND
RUN 3 6 INTV
CC
PGOOD 4 5 FB
FB
RUN 3 4
MS8E PACKAGE
8-LEAD PLASTIC MSOP
DCB PACKAGE
T = 150C, = 40C/W, = 10C/W
JMAX JA JC
6-LEAD (2mm 3mm) PLASTIC DFN
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
T = 125C, = 64C/W, = 9.6C/W
JMAX JA JC
EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PCB
o r Der i n F Ma T
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3621EDCB#PBF LTC3621EDCB#TRPBF LGDG 6-Lead (2mm 3mm) Plastic DFN 40C to 125C
LTC3621IDCB#PBF LTC3621IDCB#TRPBF LGDG 6-Lead (2mm 3mm) Plastic DFN 40C to 125C
LTC3621EDCB-3.3#PBF LTC3621EDCB-3.3#TRPBF LGQF 40C to 125C
6-Lead (2mm 3mm) Plastic DFN
LTC3621IDCB-3.3#PBF LTC3621IDCB-3.3#TRPBF LGQF 40C to 125C
6-Lead (2mm 3mm) Plastic DFN
LTC3621EDCB-5#PBF LTC3621EDCB-5#TRPBF LGQC 6-Lead (2mm 3mm) Plastic DFN 40C to 125C
LTC3621IDCB-5#PBF LTC3621IDCB-5#TRPBF LGQC 6-Lead (2mm 3mm) Plastic DFN 40C to 125C
LTC3621EMS8E#PBF LTC3621EMS8E#TRPBF LTGDH 8-Lead Plastic MSOP 40C to 125C
LTC3621IMS8E#PBF LTC3621IMS8E#TRPBF LTGDH 8-Lead Plastic MSOP 40C to 125C
LTC3621HMS8E#PBF LTC3621HMS8E#TRPBF LTGDH 8-Lead Plastic MSOP 40C to 150C
LTC3621EMS8E-3.3#PBF LTC3621EMS8E-3.3#TRPBF LTGNY 8-Lead Plastic MSOP 40C to 125C
LTC3621IMS8E-3.3#PBF LTC3621IMS8E-3.3#TRPBF LTGNY 8-Lead Plastic MSOP 40C to 125C
LTC3621HMS8E-3.3#PBF LTC3621HMS8E-3.3#TRPBF LTGNY 8-Lead Plastic MSOP 40C to 150C
LTC3621EMS8E-5#PBF LTC3621EMS8E-5#TRPBF LTGNX 8-Lead Plastic MSOP 40C to 125C
LTC3621IMS8E-5#PBF LTC3621IMS8E-5#TRPBF LTGNX 8-Lead Plastic MSOP 40C to 125C
LTC3621HMS8E-5#PBF LTC3621HMS8E-5#TRPBF LTGNX 8-Lead Plastic MSOP 40C to 150C
LTC3621EDCB-2#PBF LTC3621EDCB-2#TRPBF LGHY 6-Lead (2mm 3mm) Plastic DFN 40C to 125C
LTC3621IDCB-2#PBF LTC3621IDCB-2#TRPBF LGHY 6-Lead (2mm 3mm) Plastic DFN 40C to 125C
LTC3621EDCB-23.3#PBF LTC3621EDCB-23.3#TRPBF LGQG 40C to 125C
6-Lead (2mm 3mm) Plastic DFN
LTC3621IDCB-23.3#PBF LTC3621IDCB-23.3#TRPBF LGQG 40C to 125C
6-Lead (2mm 3mm) Plastic DFN
LTC3621EDCB-25#PBF LTC3621EDCB-25#TRPBF LGQD 6-Lead (2mm 3mm) Plastic DFN 40C to 125C
LTC3621IDCB-25#PBF LTC3621IDCB-25#TRPBF LGQD 6-Lead (2mm 3mm) Plastic DFN 40C to 125C
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For more information www.linear.com/LTC3621
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