DC/DC Converter. LTC3538 Datasheet

LTC3538 Converter. Datasheet pdf. Equivalent

Part LTC3538
Description 800mA Synchronous Buck-Boost DC/DC Converter
Feature www.DataSheet4U.com LTC3538 800mA Synchronous Buck-Boost DC/DC Converter FEATURES ■ ■ DESCRIPTION .
Manufacture Linear Technology
Datasheet
Download LTC3538 Datasheet



LTC3538
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FEATURES
Regulated Output with Input Voltages Above,
Below, or Equal to the Output
800mA Continuous Output Current from a Single
Lithium-Ion/Polymer Cell
Single Inductor
1MHz Fixed Frequency Operation
Output Disconnect in Shutdown
2.4V to 5.5V Input
35μA Quiesecent Current in Burst Mode Operation
<5μA Shutdown Current
Internal Soft-Start
Small, Thermally Enhanced 8-Lead (2mm x 3mm)
DFN package
APPLICATIONS
Miniature Hard Disk Drives
MP3 Players
Digital Cameras
Cellular Handsets
PDAs, Handheld PC
GPS Receivers
LTC3538
800mA Synchronous
Buck-Boost
DC/DC Converter
DESCRIPTION
The LTC®3538 is a highly efficient, low noise, buck-boost
DC/DC converter that operates from input voltages above,
below, and equal to the output voltage. The topology
incorporated in the IC provides a continuous transfer
function through all operating modes, making the product
ideal for single Lithium Ion or multicell Alkaline or NiMH
applications where the output voltage is within the battery
voltage range.
The LTC3538 is suited for use in Micro Hard Disk Drive
(μHDD) applications with its 800mA current capability. Burst
Mode® operation provides high efficiency at light loads.
The LTC3538 includes two 0.17Ω N-channel and two
0.2Ω P-channel MOSFET switches. Operating frequency
is internally set to 1MHz to minimize solution footprint
while maximizing efficiency.
Other features include <5μA shutdown current, internal
soft-start, short circuit protection and thermal shutdown.
The LTC3538 is available in a low profile (0.75mm), ther-
mally enhanced 8-lead (2mm × 3mm) DFN package.
, LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology
Corporation. All other trademarks are the property of their respective owners. Protected by
U.S. Patents including 5481178, 6304066, 6580258, 6166527, 6404251.
TYPICAL APPLICATION
VIN
2.9V TO 4.2V
Li-Ion/Polymer to 3.3V at 800mA
L1
3.3μH
LTC3538
SW1 SW2
R1
464k
VOUT
3.3V
800mA
10k
CIN
10μF
PWM
VIN VOUT
BURST
BURST
GND
FB
VC
ON OFF SD
33pF
COUT
22μF
15k
330pF
R2
200k
3538 TA01
Efficiency vs VIN
100
VOUT = 3.3V
ILOAD = 200mA
95
90
85
80
2.4 2.9 3.4 3.9 4.4 4.9 5.4
VIN (V)
3538 TA01b
3538f
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LTC3538
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LTC3538
ABSOLUTE MAXIMUM RATINGS
(Note 1)
VIN,VOUT Voltage .......................................... –0.3V to 6V
SW1,SW2 Voltage
DC............................................................ –0.3V to 6V
Pulsed < 100ns........................................... –1V to 7V
BURST, FB Voltage....................................... –0.3V to 6V
Operating Temperature (Note 2)............... –40°C to 85°C
Maximum Junction Temperature (Note 4)............. 125°C
Storage Temperature Range................... –65°C to 125°C
PACKAGE/ORDER INFORMATION
TOP VIEW
FB 1
8 VIN
VC 2
GND 3
7 SW1
9
6 SW2
BURST 4
5 VOUT
DCB PACKAGE
8-LEAD (2mm × 3mm) PLASTIC DFN
TJMAX = 125°C
θJA = 75°C/W 4-LAYER BOARD, θJC = 13.5°C/W
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
LTC3538EDCB#PBF
LTC3538EDCB#TRPBF LCRB
8-Lead (2mm × 3mm) Plastic DFN
LEAD BASED FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
LTC3538EDCB
LTC3538EDCB#TR
LCRB
8-Lead (2mm × 3mm) Plastic DFN
Consult LTC Marketing for parts specified with wider operating temperature ranges.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
TEMPERATURE RANGE
–40°C to 85°C
TEMPERATURE RANGE
–40°C to 85°C
ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = VOUT = 3.6V, BURST = 0V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
Input Voltage
2.4
5.5 V
Feedback Voltage
(Note 5)
0.980 1.00 1.020
V
Feedback Input Current
(Note 5)
1 50
nA
VIN Quiescent Current – Shutdown
VIN Quiescent Current – Active
VIN Quiescent Current – Sleep
NMOS Switch Leakage
VC = 0V, Not Including Switch Leakage
FB = 0.8V
FB = 1.2V, BURST = VIN
Switches B and C
1.5 5
1 1.8
35 60
0.1 7
μA
mA
μA
μA
PMOS Switch Leakage
Switches A and D
0.1 10
μA
NMOS Switch On-Resistance
Switches B and C
0.17 Ω
PMOS Switch On-Resistance
Switches A and D
0.2 Ω
Input Current Limit
1.4
2
A
Reverse Current Limit
0.5 A
Burst Mode Operational Peak Current
0.9 A
Maximum Duty Cycle
Boost (%Switch C On)
Buck (% Switch A On)
Buck (% Switch D On)
70
100
100
88
%
%
%
3538f
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