Datasheet LTC3417A (Analog Devices)

LTC3417A Dual Synchronous 1.5A/1A 4MHz Step-Down DC/DC Regulator
FeaTures DescripTion
n
High Efficiency: Up to 95%
The LTC®3417A is a dual constant frequency, synchronous n
1.5A/1A Guaranteed Minimum Output Current
step-down DC/DC converter. Intended for medium power n
Synchronizable to External Clock
applications, it operates from a 2.25V to 5.5V input volt- n
No Schottky Diodes Required
age range and has a constant programmable switching n
Programmable Frequency Operation: 1.5MHz or
frequency, allowing the use of tiny, low cost capacitors
Adjustable From 0.6MHz to 4MHz
and inductors 2mm or less in height. Each output voltage n
Low RDS(ON) Internal Switches
is adjustable from 0.8V to 5V. Internal, synchronous, low n Short-Circuit Protected RDS(ON) power switches provide high efficiency without n VIN: 2.25V to 5.5V the need for external Schottky diodes. n Current Mode Operation for Excellent Line and Load A user selectable mode input allows the user to trade Transient Response off ripple voltage for light load efficiency. Burst Mode® n 125µA Quiescent Current in Sleep Mode operation provides high efficiency at light loads, while n Ultralow Shutdown Current: IQ < 1µA Pulse Skip mode provides low ripple noise at light loads. n Low Dropout Operation: 100% Duty Cycle A phase mode pin allows the second channel to operate n Power Good Output in-phase or 180° out-of-phase with respect to channel 1. n Phase Pin Selects 2nd Channel Phase Relationship Out-of-phase operation produces lower RMS current on VIN with Respect to 1st Channel and thus a lower RMS derating on the input capacitor. n Internal Soft-Start with Individual Run Pin Control n Available in Small Thermally Enhanced To further maximize battery life, the P-channel MOSFETs (5mm × 3mm) DFN and 20-Lead TSSOP Packages are turned on continuously in dropout (100% duty cycle)
applicaTions
and both channels draw a total quiescent current of only 125µA. In shutdown, the device draws <1µA. n GPS/Navigation L, LT, LTC, LTM and Burst Mode are registered trademarks and Hot Swap and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the property of their n Digital Cameras respective owners. Protected by U.S. Patents including 5481178, 6580258, 6304066, 6127815, n PC Cards 6498466, 6611131, 6144194. n Wireless and DSL Modems n General Purpose Point of Load DC/DC
Typical applicaTion OUT2 Efficiency (Burst Mode Operation)
VIN 2.5V TO 5.5V 100 10 10µF REFER TO FIGURE 4 VIN FREQ 95 EFFICIENCY 1 V 1.5µH 2.2µH OUT1 VOUT2 1.8V SW1 SW2 2.5V POWER LOSS (W) 22pF 22pF 1.5A 1A 90 VIN RUN1 RUN2 VIN 0.1 LTC3417A 85 511k 866k VFB1 VFB2 0.01 47µF 412k EFFICIENCY (%) 412k 22µF 80 POWER LOSS ITH1 ITH2 0.001 75 V 5.9k IN = 3.6V GND 2.87k VOUT = 2.5V FREQ = 1MHz 2200pF 6800pF 70 0.0001 0.001 0.01 0.1 1 3417 TA01 LOAD CURRENT (A) 3417 TA01a 3417afc 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Package Description Revision History Related Parts