LM2670 Datasheet | National Semiconductor

Description The LM2670 series of regulators are monolithic integrated circuits which provide all of the active functions for a step-down (buck) switching regulator capable of driving up to 3A loads with excellent line and load regulation characteristics. High efficiency ( > 90%) is obtained through the use of a low ON-resistance DMOS power switch. The series consists of fixed output voltages of 3.3V, 5V and 12V and an adjustable output version. The SIMPLE SWITCHER concept provides for a plete design using a minimum number of external ponents. The switching clock frequency can be provided by an internal fixed frequency oscillator (260KHz) or from an externally provided clock in the range of 280KHz to 400Khz which allows the use of physically smaller sized ponents. A family of standard inductors for use with the LM2670 are available from several manufacturers to greatly simplify the design process. The external Sync clock provides direct and precise control of the output ripple frequency for consistent filtering or frequency spectrum positioning. The LM2670 series also has built in thermal shutdown, current limiting and an ON/OFF control input that can power down the regulator to a low 50µA quiescent current standby condition. The output voltage is guaranteed to a ± 2% tolerance. Features n Efficiency up to 94% n Simple and easy to design with (using off-the-shelf external ponents) n 150 mΩ DMOS output switch n 3.3V, 5V and 12V fixed output and adjustable (1.2V to 37V ) versions n 50µA standby current when switched OFF n ± 2%maximum output tolerance over full line and load conditions n Wide input voltage range: 8V to 40V n External Sync clock capability (280KHz to 400KHz) n 260 KHz fixed frequency internal oscillator n - 40 to +125˚C operating junction temperature range Applications n Simple to design, high efficiency ( > 90%) step-down switching regulators n Efficient system pre-regulator for linear voltage regulators n Battery chargers n munications and radio...