CURRENT (A)
LT8697
USB 5V 2.5A Output,
42V Input Synchronous Buck with
Cable Drop Compensation
FEATURES DESCRIPTION
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Wide Input Range: 5V to 42V The LT 8697 is a compact, high efficiency, high speed
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Low Dropout Under All Conditions: 450mV at 2.1A synchronous monolithic step-down switching regulator
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Accurate 5V Output: 1.3% Over Full Temperature designed to power 5V USB applications. A precise output
Range voltage and programmable cable drop compensation main-
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Programmable Cable Drop Compensation tain accurate 5V regulation at the USB socket connected
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Programmable Output Current Limit to the end of a long cable. Forced continuous operation
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Output Current Monitor allows the LT8697 to sink current, further enhancing ac-
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Dual Input Feedback Permits Regulation on Output curate 5V regulation during load transients.
of USB Switch
Accurate and programmable output current limit, a power
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Forced Continuous Mode for Fast Load Step
good indicator pin and an output current monitor pin
Response
improve system reliability and safety, allow the user to
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High Efficiency Synchronous Operation at 2MHz:
implement latch-off or auto-retry functionality and can
93% Efficiency at 2.1A, 5V from 12V
OUT IN
eliminate the need for a USB switch IC. Dual feedback al-
95% Efficiency at 0.9A, 5V from 12V
OUT IN
lows regulation on the output of a USB switch and limits
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Fast Minimum Switch-On Time: 45ns
cable drop compensation to a maximum of 5.8V output,
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Adjustable Output from 5.0V to 5.25V
protecting USB devices during fault conditions. Thermal
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Adjustable and Synchronizable: 300kHz to 2.2MHz
shutdown provides additional protection by limiting power
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Small Thermally Enhanced 3mm 5mm 24-Lead
dissipation in the IC during an overtemperature fault.
QFN Package
The LT8697 is available in a small 24-lead 3mm 5mm
APPLICATIONS package with an exposed pad for low thermal resistance.
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
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Automotive and Industrial USB
of Linear Technology Corporation. All other trademarks are the property of their respective owners.
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Precision 5V Supply
TYPICAL APPLICATION
2MHz 5V Step-Down Converter with Cable Drop Compensation Transient Response Through 3 Meters
AWG 20 Twisted-Pair Cable
V
IN
5.50 5
6V TO 42V
0.1F
3 METERS AWG 20
V
TWISTED PAIR CABLE
OUT
4.7F V BST
IN
5.25 4
3.3H
0.018 0.1
V
OUT
EN/UV SW
PG SYS
5.00 3
LT8697
47F
1nF
V
LOAD
INTV
CC 2
10k
+
1F
ICTRL ISP
4.75 2
V
LOAD
SYNC ISN
I
LOAD
5V, 2.4A
50mA/s
TR/SS USB5V
4.50 1
10nF
RT RCBL
16.5k GND PGND 18.2k
4.25 0
0.1
100s/DIV 8697 TA01b
8697 TA01a
8697fb
1
For more information www.linear.com/LT8697
LOAD
VOLTAGE (V)LT8697
ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION
(Note 1)
TOP VIEW
V , EN/UV, PG, ISP, ISN ...........................................42V
IN
SYS ...........................................................................30V
USB5V .....................................................................3mA 24 23 22 21
1
SYNC 20 USB5V
BST Above SW ............................................................4V
TR/SS 2 19 PG
TR/SS, ICTRL..............................................................4V
RT 3 SYS
18
RT, RCBL .....................................................................2V
EN/UV 4 INTV
17
CC
25
SYNC ..........................................................................6V
5
V 16 BST
IN GND
Operating Junction Temperature Range (Notes 2, 3)
6
V 15 SW
IN
LT8697E ............................................ 40C to 125C
PGND 7 14 SW
LT8697I ............................................. 40C to 125C PGND 8 SW
13
9 10 11 12
LT8697H ............................................ 40C to 150C
Storage Temperature Range .................. 65C to 150C
UDD PACKAGE
24-LEAD (3mm 5mm) PLASTIC QFN
= 46C/W, = 5C/W
JA JC
EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LT8697EUDD#PBF LT8697EUDD#TRPBF LGGW 24-Lead (3mm 5mm) Plastic QFN 40C to 125C
LT8697IUDD#PBF LT8697IUDD#TRPBF LGGW 24-Lead (3mm 5mm) Plastic QFN 40C to 125C
LT8697HUDD#PBF LT8697HUDD#TRPBF LGGW 40C to 150C
24-Lead (3mm 5mm) Plastic QFN
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to: