Flexible route to power up AMD-based systems

An International Rectifier product story

Edited by the Electronicstalk editorial team Mar 3, 2005

The IR3082 is a multiphase control IC for AMD Opteron and Athlon64 processor-powered servers and workstations.

The IR3082 is a multiphase control IC for AMD Opteron and Athlon64 processor-powered servers and workstations.

The IR3082 broadens IR's XPhase family of scalable multiphase ICs and, together with DirectFET power MOSFETs, delivers an optimised multiphase DC/DC power solution for midrange and high-end servers, voltage regulator modules (VRMs) and high-current telecomms applications.

The IR3082 control IC works with the IR3086A phase IC to provide a full-featured and flexible way to implement a complete Opteron or Athlon64 power solution.

For example, a 12V, four-phase design using one IRF6617 control FET and one IRF6691 synchronous FET per phase provides 86% efficiency for an output of 80A.

Unlike other multiphase solutions which have a fixed number of phases, IR's XPhase architecture enables scalable multiphase designs.

The IR3082 uses 5bit voltage programming and only a few external components which simplify general purpose and non-processor-specific multiphase applications.

The IR3082 includes a 5bit VID with 1.0% overall system accuracy.

An adaptive voltage-positioning feature maintains the output voltage tolerance and minimises output capacitor requirements.

A patented body braking circuit can reduce the output capacitance requirement by 25%, further reducing system costs.

A 150kHz to 1MHz programmable oscillator gives the designer additional flexibility to optimise for system efficiency and transient response.

For system protection and reliability, the IR3082 features programmable soft-start and hiccup overcurrent protection.

Current sensing is achieved with lossless inductor current sensing which improves accuracy compared with sensing circuits measuring MOSFET on-resistance.

Undervoltage lockout and overvoltage protection circuits ensure reliability of system voltages.

A power-good output signal indicates proper operation.

The IR3082 XPhase control IC is packaged in a thermally enhanced 5 x 5mm, 20-lead MLPQ package.