Datasheet LTM4624 (Analog Devices) - 8

LTM4624
OPERATION
The LTM4624 is a standalone nonisolated switch mode Current mode control provides cycle-by-cycle fast cur- DC/DC power supply. It can deliver up to 4A DC (5A rent limiting. Foldback current limiting is provided in an peak) output current with few external input and output overcurrent condition indicated by a drop in VFB reducing capacitors. This module provides precisely regulated inductor valley current to approximately 40% of the origi- output voltage adjustable between 0.6V to 5.5V via one nal value. Internal output overvoltage and undervoltage external resistor over a 4V to 14V input voltage range. comparators pull the open-drain PGOOD output low if the With an external bias supply, this module operates with output feedback voltage exits a ±10% window around the an input voltage down to 2.375V. The typical application regulation point. Continuous operation is forced during schematic is shown in Figure 20. OV and UV conditions except during start-up when the The LTM4624 contains an integrated constant on-time TRACK pin is ramping up to 0.6V valley current mode regulator, power MOSFETs, inductor, Pulling the RUN pin below 1.1V forces the controller into and other supporting discrete components. The default its shutdown state, turning off both power MOSFETs switching frequency is 1MHz. For noise-sensitive applica- and most of the internal control circuitry. At light load tions, the switching frequency can be adjusted by external currents, discontinuous mode (DCM) operation can be resistors. See the Applications Information section. enabled to achieve higher efficiency compared to continu- With current mode control and internal feedback loop ous mode (CCM) by pulling the MODE pin to SGND. The compensation, the LTM4624 module has sufficient stabil- TRACK/SS pin is used for power supply tracking and ity margins and good transient performance with a wide soft-start programming. See the Applications Informa- range of output capacitors, even with all ceramic output tion section. capacitors. 4624fd 8 For more information www.linear.com/LTM4624 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Decoupling Requirements Operation Applications Information Package Description Package Photo Design Resources Related Parts