National Semiconductor introduced a pair of high-current, synchronous buck regulators with a efficiency of 97 percent. The LM21212-1 and LM21215 regulators feature integrated high-side and low-side FETs. The LM21212-1 features 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. Both products provide peak efficiency greater than 97 percent from a 5V input to 3.3V output, and greater than 92 percent efficiency when regulating a 1.2V output from a 5V input.

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.

The LM21212-1 and LM21215 are monolithic synchronous buck regulators offered in a 4.4 mm by 6.5 mm by 0.9 mm package. The LM21212-1 is capable of delivering up to 12A of continuous output current with a switching frequency that can be synchronized to an external oscillator between 300 kHz and 1.5 MHz. The LM21215 features a fixed 500 kHz switching frequency and is capable of delivering up to 15A. 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. National’s buck regulators are available now and offered in 20-pin thermally-enhanced TSSOP packages. Priced in quantities of 1,000, the LM21212-1 is $3.85 and the LM21215 is $4.15. A version of the LM21212-1 with adjustable switching frequency will be available in March 2011.