Power controller takes on Intel i865/i875 boards

Edited by the Electronicstalk editorial team Jul 17, 2003

The ISL6505 is a four-output linear regulator with an ACPI control interface.

The ISL6505 is a four-output linear regulator with an ACPI control interface.

This industry-enabling IC contains four linear low-dropout (LDO) regulators, switching, monitoring, protection and control functions in a 20-lead wide-body small-outline IC (SOIC) or space-saving, near-chip-scale, 20-pad 5 x 5mm QFN package.

The ISL6505 is designed to provide the industry's highest performance-to-price ratio for powering systems on new Intel i865 and i875 chipset-based motherboards with Hyper-Threading Technology.

The ISL6505 regulates a resistor-programmable +1.2 to 1.5V for the LAN or Gigabit Ethernet (GbE) controller, +1.2V for the VID generating circuitry residing onboard the CPU, +3.3V (dual) for the PCI slots, LAN controller, and auxiliary components, and +5V (dual) for the USB port, keyboard, and mouse.

2% regulation is ensured on all outputs.

The ISL6505's QFN package provides the industry's best thermal dissipation and its near-chip-scale size requires the least board space.

Four discrete linear regulators are replaced by the ISL6505, along with their associated components.

One significant advantage of the ISL6505 is that it eliminates the need for a separate five-lead SOT-23-packaged LDO required for the VID generating circuit.

The integrated VCC-VID LDO in the ISL6505 provides 180mA current - 30mA more than discrete VCC-VID LDOs available today.

The ISL6505 enables quick cut-and-paste designs from one motherboard model to the next, due to its simplicity.

There's no need for glue logic, as the chip is designed from the ground up to interface directly with the SLP_S3, and SLP_S5 ACPI signals from Intel's i865/i875 chipsets.

The benefit of this design is that it offers the industry's lowest-noise computer motherboard ACPI power management solution with seamless switching between active and standby states while maintaining continuous voltage regulation.

Typical discrete solutions use various onboard regulators for LAN/GbE, VCC-VID, PCI slots, Universal Serial Bus, keyboard, and mouse consisting of voltage references, resistors, capacitors, op amps, diodes, bipolar and MOS transistors.

Noise coupled into these circuits can result in "illegal" ACPI state transitions and power upsets that lead to loss of critical data.

Switching between supplies while they have not fully stabilised, or switching several loads into the same supply line causes momentary power overloads and brownouts, which leads to output regulation falling outside design limits.

Glitches may trick the regulators to enter a fault state or latch off.

The typical result of data loss is a system crash, followed by the need to reboot the system.

A typical discrete ACPI power management system takes up precious board area and lacks system monitoring and protection functions that could otherwise significantly reduce the total cost of ownership and prolong the life of an ACPI-compliant computer.

The surface-mount placement cost associated with these discrete components also contributes to a higher implementation cost.

Additionally, the reliability of the computer is potentially reduced, as compared to an integrated solution, as there are many more components on the board that could fail over time.

The ISL6505 provides the industry's highest degree of integration, greatly reducing parts count, PCB area, and bill-of-materials cost, while reducing the time to market.

A full set of monitoring and protection circuits ensures safe and reliable operation.

Short-circuit protection is provided for all outputs.

Other protections include thermal shutdown, under-voltage lockout and VID power good.

A special LAN pin is provided to select LAN or Gigabit Ethernet where VOUT1 is always on for LAN mode and on only during active states for the Gigabit Ethernet mode.

The ISL6505 ACPI controller is part of a total system solution with Intersil's CPU core multiphase regulators and DDR memory power controllers to provide a complete VRM10/i865/i875 computer motherboard power system solution enabling Intel's Hyper-Threading Technology.

Intersil's new ISL6556A/B and ISL6561 two-to-four phase VRM10 PWM controllers, combined with the HIP660XB or ISL6605 mosfet drivers, provide solid CPU core regulation.

The new ISL6532A dual DDR memory controller regulates DDR memory core (VDDQ), DDR memory termination bus (VTT), and chipset core or Advanced Graphics Port (AGP) power.

Intersil delivers the industry's highest performance-to-price ratio across-the-board power solutions for the new Intel i865 and i875 chipset computing platforms that is Intel's Hyper-Threading Technology.