LTC3417AIFE(RevA) View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
LTC3417AIFE Datasheet PDF : 20 Pages
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LTC3417A
Dual Synchronous
1.5A/1A 4MHz
Step-Down DC/DC Regulator
FEATURES
■ High Efficiency: Up to 95%
■ 1.5A/1A Guaranteed Minimum Output Current
■ Synchronizable to External Clock
■ No Schottky Diodes Required
■ Programmable Frequency Operation: 1.5MHz or
Adjustable From 0.6MHz to 4MHz
■ Low RDS(ON) Internal Switches
■ Short-Circuit Protected
■ VIN: 2.25V to 5.5V
■ Current Mode Operation for Excellent Line and Load
Transient Response
■ 125µA Quiescent Current in Sleep Mode
■ Ultralow Shutdown Current: IQ < 1µA
■ Low Dropout Operation: 100% Duty Cycle
■ Power Good Output
■ Phase Pin Selects 2nd Channel Phase Relationship
with Respect to 1st Channel
■ Internal Soft-Start with Individual Run Pin Control
■ Available in Small Thermally Enhanced
(5mm × 3mm) DFN and 20-Lead TSSOP Packages
U
APPLICATIO S
■ GPS/Navigation
■ Digital Cameras
■ PC Cards
■ Wireless and DSL Modems
■ General Purpose Point of Load DC/DC
DESCRIPTIO
The LTC®3417A is a dual constant frequency, synchro-
nous step-down DC/DC converter. Intended for medium
power applications, it operates from a 2.25V to 5.5V input
voltage range and has a constant programmable switch-
ing frequency, allowing the use of tiny, low cost capacitors
and inductors 2mm or less in height. Each output voltage
is adjustable from 0.8V to 5V. Internal, synchronous, low
RDS(ON) power switches provide high efficiency without
the need for external Schottky diodes.
A user selectable mode input allows the user to trade off
ripple voltage for light load efficiency. Burst Mode® opera-
tion provides high efficiency at light loads, while Pulse
Skip mode provides low ripple noise at light loads. A phase
mode pin allows the second channel to operate in-phase
or 180° out-of-phase with respect to channel 1. Out-of-
phase operation produces lower RMS current on VIN and
thus a lower RMS derating on the input capacitor.
To further maximize battery life, the P-channel MOSFETs
are turned on continuously in dropout (100% duty cycle)
and both channels draw a total quiescent current of only
100µA. In shutdown, the device draws <1µA.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Burst Mode is a registered trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466,
6611131, 6144194
TYPICAL APPLICATIO
VIN
2.5V TO 5.5V
VOUT1
1.8V
1.5A
47µF
10µF
1.5µH
22pF
VIN
511k
412k
5.9k
2200pF
VIN
FREQ
SW1
SW2
RUN1
RUN2
LTC3417A
VFB1
VFB2
ITH1
ITH2
GND
2.2µH
VIN
22pF
866k
412k
2.87k
6800pF
3417 TA01
VOUT2
2.5V
1A
22µF
OUT2 Efficiency
(Burst Mode Operation)
100 REFER TO FIGURE 4
10
95
EFFICIENCY
1
90
0.1
85
0.01
80
POWER LOSS
75
70
0.001
0.001
VIN = 3.6V
VOUT = 2.5V
FREQ = 1MHz 0.0001
0.01
0.1
1
LOAD CURRENT (A)
3417 TA01a
3417afa
1
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