International Rectifier Intros IR3621M/F PWM Driver ICs
International Rectifier Corp. (IR, El Segundo, CA) introduced its new IR3621M and IR3621F voltage-mode, dual-output, bi-phase, synchronous buck, controller driver ICs for high-performance, point-of-load (POL) buck converters used in networking, computing, and communications systems. The IR3621 includes a full suite of power-management features, including pre-bias protection, sequencing capability, hiccup current-limit protection, and tight voltage reference accuracy.
The IRDC3621 Design Kit, featuring the new IR3621M, demonstrates the complete dc-dc converter performance, while showcasing its full range of power-management features. For 12 V input, 2.5 V output, the converter achieves up to 86 percent efficiency at 15 A full load, and 400 kHz switching frequency when the IR3621M is used with two optimized HEXFET® MOSFETs, such as the IRF7821 and IRF8113. Typical applications include powering dual-logic, application-specific ICs (ASICs); DDR memory power management; or other multi-rail or two-phase requirements.
The IR3621 is offered in two package styles -- the IR3621F is housed in a 28-lead TSSOP package and the IR3621M is housed in a 32-pin, 5 mm x 5 mm, MLPQ package. The IR3621M provides ±1 percent output-voltage accuracy, and the IR3621F provides ±1.35 percent output-voltage accuracy. Both provide pre-bias protection, and are suitable for non-isolated 0.8 V to 3.3 V output dc-dc POL converters with either dual-output rails up to 15 A each, or single output rails up to 30 A.
The pre-bias feature included in the IR3621 prevents the discharge of any pre-existing output voltage during the startup of the POL, eliminating negative voltage spikes on the output. For single-output, bi-phase configurations, the IR3621 uses the output inductor dc resistance as a current-sharing reference, eliminating external shunt resistors. The IR3621 features 180° out-of-phase operation with programmable switching frequency up to 500 kHz, reducing input and output filtering requirements and resulting in lower component count.
The new dual, synchronous buck controller and driver ICs are now available. Pricing in 10,000-unit quantities is $1.45 each for the IR3621F or IR3621FTR, and $1.50 each for the IR3621M and IR3621MTR. Prices are subject to change. A lead-free version of the IR3621M (32-pin MLPQ) will be available in the fourth quarter of 2005, as part number IR3621MPbF. The device will be compliant with the Restriction of Hazardous Substances Directive.
