Date: 24/02/2011

97% efficient 12A and 15A synchronous regulator ICs for powering FPGA and processors

National Semiconductor Corp. has introduced monolithic 12A and 15A current rated synchronous buck regulators with the industry's highest efficiency at 97 percent. The LM21212-1 and LM21215 are suggested for high-performance FPGAs, ASICs and microprocessors used in low-voltage applications such as wireless, networking and optical communications infrastructure.

National said it will showcase the LM21212-1 and LM21215 at the Applied Power Electronics Conference and Expo (APEC) in Fort Worth, Texas, March 6-10.

The LM21212-1 and LM21215 integrate high-side and low-side FETs to deliver an output current up to 12 amps with synchronizable switching frequency and the LM21215 provides a resistor-programmable current limit, allowing up to 15 amps of continuous output current, offering the industry's best power density. Both devices offer 97 percent power efficiency from a 5V input to 3.3V output, and greater than 92 percent efficiency when regulating a 1.2V output from a 5V input.

National Semiconductor claims under typical operating conditions such as 5 Vin, 1.2 Vout, 10A, 500 kHz and 25 degrees C ambient, the regulators provide a three percent to five percent efficiency improvement and up to 10 degrees C cooler case temperature than similar products on the market today.

Technical features of these synchronous buck regulators are:

1. 12 Amps rated LM21212-1 operates with a switching frequency that can be synchronized to an external oscillator between 300 kHz and 1.5 MHz.
2. 15 Amp rated LM21215 features a fixed 500 kHz switching frequency.
3. The regulators are optimized to work over an input voltage range of 2.95V to 5.5V and produce an output voltage down to 0.6V.
4. A programmable over-current protection feature allows a user to specify the peak current level.
5. Internal over voltage protection circuit provides increased system reliability, while a precision enable pin and integrated UVLO allow turn-on of the device to be tightly controlled and sequenced.
6. Start-up inrush currents are limited by both an internally fixed and externally adjustable soft-start circuit.
7. Both regulators provide a monotonic startup into a pre-biased load, preventing the devices from sinking current until the internal soft-start ramp exceeds the voltage at the feedback pin.
8. Fault detection and supply sequencing are also possible with the integrated power good circuit. The regulators are designed to work well in multi-rail power supply architectures, as the output voltage can be configured to track a higher voltage rail using the SS/TRK pin.
9. Other features include high noise immunity, narrow duty cycle, and stability compensation can be achieved using any type of output capacitor.

Package: Thermally enhanced TSSOP of size 4.4 mm by 6.5 mm by 0.9 mm
Price: Each $3.85 for 1K pieces
Availability: Mar 2011
Editorial Product Rating: *** (High Value) 97% effeciency is very good compared to similar devices