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LT1681ISW

Description
Switching Voltage Regulators LT1681 - Dual Transistor Synchronous Forward Controller
CategoryPower/power management    The power supply circuit   
File Size297KB,20 Pages
ManufacturerADI
Websitehttps://www.analog.com
Download Datasheet Download user manual Parametric Compare View All

LT1681ISW Overview

Switching Voltage Regulators LT1681 - Dual Transistor Synchronous Forward Controller

LT1681ISW Parametric

Parameter NameAttribute value
Is it Rohs certified?incompatible
MakerADI
Objectid4002727777
package instructionSOP,
Reach Compliance Codenot_compliant
ECCN codeEAR99
compound_id264248252
Analog Integrated Circuits - Other TypesSWITCHING CONTROLLER
control modeCURRENT-MODE
Maximum input voltage18 V
Minimum input voltage9 V
Nominal input voltage12 V
JESD-30 codeR-PDSO-G20
JESD-609 codee0
length12.8 mm
Humidity sensitivity level1
Number of functions1
Number of terminals20
Maximum operating temperature85 °C
Minimum operating temperature-40 °C
Package body materialPLASTIC/EPOXY
encapsulated codeSOP
Package shapeRECTANGULAR
Package formSMALL OUTLINE
Peak Reflow Temperature (Celsius)235
Certification statusNot Qualified
Maximum seat height2.65 mm
surface mountYES
Switch configurationPUSH-PULL
Maximum switching frequency700 kHz
Temperature levelINDUSTRIAL
Terminal surfaceTin/Lead (Sn/Pb)
Terminal formGULL WING
Terminal pitch1.27 mm
Terminal locationDUAL
Maximum time at peak reflow temperature20
width7.5 mm
FEATURES
s
s
LT1681
Dual Transistor
Synchronous Forward Controller
DESCRIPTIO
The LT
®
1681 controller simplifies the design of high power
synchronous dual transistor forward DC/DC converters. The
part employs fixed frequency current mode control and
supports both isolated and nonisolated topologies. The IC
drives external N-channel power MOSFETs and operates with
input voltages up to 72V.
The LT1681’s operating frequency is programmable and can
be synchronized up to 350kHz. Switch phase is also con-
trolled during synchronized operation to accommodate mul-
tiple converter systems. Internal logic guarantees 50% maxi-
mum duty cycle operation to prevent transformer saturation.
The LT1681 incorporates a soft-start feature that provides a
controlled increase in supplied current during start-up and
after an undervoltage lockout or overvoltage/overcurrent
event.
The part is available in a 20-lead wide SO package to support
high voltage pin-to-pin clearance.
, LTC and LT are registered trademarks of Linear Technology Corporation.
s
s
s
s
s
s
s
s
s
s
High Voltage: Operation Up to 72V
Synchronizable Operating Frequency and Output
Switch Phase for Multiple Controller Systems
Fixed Frequency Operation to 350kHz
Adaptive and Adjustable Blanking
Synchronous Rectifier Driver
Local 1% Voltage Reference
Undervoltage Lockout Protection with Hysteresis
Input Overvoltage Protection
Programmable Start Inhibit
Transformer Primary Saturation Protection
Optocoupler Feedback Support
Soft-Start Control
APPLICATIO S
s
s
s
s
Isolated Telecommunication Systems
Personal Computers and Peripherals
Lead Acid Battery Backup Systems
Automotive and Heavy Equipment
TYPICAL APPLICATIO
L1
4.7µH
V
IN+
36V-72V DC to 5V/7A Synchronous Forward Converter (Half-Brick Footprint)
L2
4.1µH
6
Q1
MURS120T3
C2
22µF
100V
C3
1.5µF
100V
V
IN–
C2:SANYO 100MV22AX
C3, C4: VITRAMON VJ1825Y155MXB
C5: 4X KEMET T510X337KO10AS
L1: COILCRAFT DO1608C-472
L2: PANASONIC ETQP6F4R1LF4
Q1,Q3:100V SILICONIX SUD40N10-25
Q5,Q6: SILICONIX Si4450
T1:COILTRONICS VP5-1200
Q10: ON SEMI MMBT3906LTI
73.2k
1%
270k
0.25W
20k
CMPZ-
5248B
15V
C4
1.5µF
100V
MURS120T3
7
5
8
4
0.025Ω
1/2W
9
T1 Q5
+
Q3
ZVN3310F
BAT54
1OV
BIAS
MMBD914LT1
0.1µF
100V
10k
330pF
5V
OUT
3.3Ω
0.047µF
8
1OV
BIAS
BAS21
14
20
17
19
18
16
11
12
15
V
CC
V
BST
BLKSENS TG BSTREF BG SENSE T
MAX
PGND 13
SG
2
LT1681
OVLO
9
1
THERM SYNC SGND SS V
C
V
FB
SHDN 5V
REF
F
SET
6
5
52.3k
1µF
150pF
3
7
4
8
10
100Ω
4.7nF
0.01µF
CMPZ5248B
18V
0.1µF
10k
1nF 24k
56k
1.24k
1%
3.01k
1%
1k
1%
51Ω
+
68µF
20V
Q10
LTC1693-2
6
V
CC1
V
CC2
5
3
IN2
OUT2
7
1
IN1
OUT1
2
4
GND2
GND1
U
U
U
V
OUT
= 5V
I
OUT
= 7A
V
OUT+
1
2
3
10Ω
0.25W
1nF
100V
10
1nF
11
100V
10Ω
0.25W
12
MBR-
0540T1
Q6
+
C5
330µF
10V
4.7Ω
V
OUT–
100Ω
FZT690
4.7µF
16V
CMPZ5242B
12V
2k
0.22µF
50V
1681 TA01
1681f
1

LT1681ISW Related Products

LT1681ISW LT1681ISW#TR LT1681ESW#TR
Description Switching Voltage Regulators LT1681 - Dual Transistor Synchronous Forward Controller Switching Voltage Regulators LT1681 - Dual Transistor Synchronous Forward Controller Switching Regulator LT1681 - Dual Transistor Synchronous Forward Controller
Is it Rohs certified? incompatible incompatible incompatible
Maker ADI ADI ADI
package instruction SOP, SOP, SOP,
Reach Compliance Code not_compliant not_compliant not_compliant
ECCN code EAR99 EAR99 EAR99
Analog Integrated Circuits - Other Types SWITCHING CONTROLLER SWITCHING CONTROLLER SWITCHING CONTROLLER
control mode CURRENT-MODE CURRENT-MODE CURRENT-MODE
Maximum input voltage 18 V 18 V 18 V
Minimum input voltage 9 V 9 V 9 V
Nominal input voltage 12 V 12 V 12 V
JESD-30 code R-PDSO-G20 R-PDSO-G20 R-PDSO-G20
JESD-609 code e0 e0 e0
length 12.8 mm 12.8 mm 12.8 mm
Humidity sensitivity level 1 1 1
Number of functions 1 1 1
Number of terminals 20 20 20
Maximum operating temperature 85 °C 85 °C 70 °C
Minimum operating temperature -40 °C -40 °C -
Package body material PLASTIC/EPOXY PLASTIC/EPOXY PLASTIC/EPOXY
encapsulated code SOP SOP SOP
Package shape RECTANGULAR RECTANGULAR RECTANGULAR
Package form SMALL OUTLINE SMALL OUTLINE SMALL OUTLINE
Peak Reflow Temperature (Celsius) 235 235 235
Certification status Not Qualified Not Qualified Not Qualified
Maximum seat height 2.65 mm 2.65 mm 2.65 mm
surface mount YES YES YES
Switch configuration PUSH-PULL PUSH-PULL PUSH-PULL
Maximum switching frequency 700 kHz 700 kHz 700 kHz
Temperature level INDUSTRIAL INDUSTRIAL COMMERCIAL
Terminal surface Tin/Lead (Sn/Pb) Tin/Lead (Sn/Pb) Tin/Lead (Sn/Pb)
Terminal form GULL WING GULL WING GULL WING
Terminal pitch 1.27 mm 1.27 mm 1.27 mm
Terminal location DUAL DUAL DUAL
Maximum time at peak reflow temperature 20 20 20
width 7.5 mm 7.5 mm 7.5 mm
Objectid 4002727777 4002729714 -
compound_id 264248252 263781655 -
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