International Rectifier Introduces Two 1% Accurate PWM Controllers to Simplify DC-DC Power Conversion

EL SEGUNDO, Calif. — September 2005 -- International Rectifier, IR (NYSE: IRF), a world leader in power management technology, today introduced two one-percent accurate, single output, synchronous buck PWM controllers with 4.5V to 16V input voltage capability. The new IR3637SPbF and IR3637ASPbF are compact and simple solutions for up to 15A DC-DC point-of-load applications such as dual data rate (DDR) memory, field programmable gate arrays (FPGAs), and video graphics processors. Combined with International Rectifier’s broad selection of power MOSFETs, these two controllers offer greater design flexibility and improved performance versus integrated solutions.

The two PWM controllers feature a 0.8V, one percent accurate voltage reference. In next generation systems, peripheral rails can require as little as 3% total voltage error tolerance to ensure data signal integrity. The two new PWM ICs with one percent accuracy allow designers to meet this stringent requirement. Both ICs include short-circuit protection, input under-voltage lockout, and an externally programmable soft-start function. The devices are available in the standard SO-8 package.

The IR3637SPbF operates at 400kHz, suitable for output currents up to 15A for applications including desktop motherboard peripheral rails such as DDR memory and chip set power.

The IR3637ASPbF runs at 600kHz and provides optimum efficiency in applications requiring less than 7A such as FPGAs. The 600kHz operating frequency reduces required inductor size when compared to lower frequency solutions and increases control loop bandwidth for improved transient response. Both PWM controllers are suitable for general purpose DC-DC conversion in a variety of other switching power supply applications.

“For 12V input applications, designers have limited choices for integrated point of load solutions. International Rectifier has put together these two new ICs with its world class power MOSFETs to create a menu of options enabling the ‘ease of use benefits’ that integrated solutions offer with the flexibility and performance of discrete topologies,” said Faisal Ahmad, Marketing Manager for DC-DC Computing Products.

A list of the wide array of compatible MOSFETs for the new PWM controllers is posted on the IR Web site.

Also available is the IRDC3637 Reference Design, which demonstrates performance for a 5V input, 1.8V output, DC-DC converter delivering 7A of output current, using the IR3637SPbF. For more details, go to the International Rectifier DC-DC Reference Designs page

Part Number Package Switching Frequency Iout Vin Max Duty Cycle Reference Voltage
IR3637SPbF SO-8 400kHz Up to 15A 4V – 16V 85% 0.8
IR3637ASPbF SO-8 600kHz Up to 7A 4V – 16V 85% 0.8

Availability and Pricing

Pricing for both the IR3637SPbF and the IR3637ASPbF is US $0.79 each in 10,000-unit quantities, and are available either in tubes or Tape & Reel. Prices are subject to change. The devices are lead-free and are compliant with the Restriction of Hazardous Substances Directive (RoHS).