Part # LM2630 datasheet

Part Manufacturer: National Semiconductor

National Semiconductor

Part Description: LM2630 Synchronous Step-Down Power Supply Controller

Part Details:

LM2630 July 2005 Synchronous LM2630Synchronous Step-Down Power Supply ControllerGeneral Description Features The LM2630 controller provides all the active functions for n 4.5V to 30V input range step-down (buck) switching converters. These dc-to-dc con- n Adjustable output (1.8V to 6V) verters provide core CPU power in battery-operated sys- n 200 kHz to 400 kHz adjustable operating frequency tems. Step-Down n Externally synchronizable High efficiency is achieved by using synchronous rectifica- n On-board power good function tion and pulse-skipping mode operation at light load. Inex- n Precision 1.24V reference output pensive N-channel MOSFETs are used to reduce system n 0.8 mA typical quiescent current cost. Bootstrap circuit is used to drive the high-side n 0.1 µA shutdown current N-channel MOSFET. n Thermal shutdown Current mode control scheme is used to improve line regu- n Direct current limit protection lation and transient response, also provides cycle-by-cyclecurrent limiting. n Input undervoltage lockout Power n Output Undervoltage shutdown protection The operating frequency is adjustable between 200 kHz and400 kHz. An external shutdown pin can be used to disable n Programmable soft-start function the device and reduce the quiescent current to 0.1 µA. In low n Tiny TSSOP package noise applications, bringing the FPWM pin high can force the Supply device to operate in constant frequency mode. Other fea- Applications tures include the external synchronization pin, and the n Notebook and subnotebook computers PGOOD pin to indicate the state of the output voltage. n Cellular phones Protection circuitry includes thermal shutdown, undervoltage n Portable instruments shut down, soft-start capability, and two levels of current n Battery-powered digital devices Controller limits: The first level simply limits the load current directly; atthe second level, if the load pulls the output voltage downbelow 80% of the regulated value, the chip willshut down.This latched operation is disabled during startup, but aninternal timer will enable it if the output does not come up inthe preset time. Typical Application Circuit 10012001 © 2005 National Semiconductor Corporation DS100120 Absolute Maximum Ratings (Note 1)

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LM2630.pdf Datasheet