IRU3033

1

Rev. 1.7

07/17/02

www.irf.com

8-PIN PWM SWITCHER AND LINEAR CONTROLLER IC

TYPICAL APPLICATION

Figure 1 - Typical application of IRU3033 in a flexible mother board designed for

Intel P55

™ , P54™ , AMD K5, K6™ as well as Cyrix M1™ and M2™ applications.

8-PIN PLASTIC SOIC (S)

0 To 70

IRU3033CS

Notes: P54C, P55C, Pentium II are

trademarks of Intel Corp. K5 & K6

are trademarks of AMD Corp. Cyrix

6X86L, M1, M2 are trademarks of

Cyrix Corp. Power PC is trademark

of IBM Corp.

DESCRIPTION

The IRU3033 IC combines a switching controller and a

linear regulator controller all in a compact 8-pin surface

mount package, providing a total solution for dual sup-

ply processor applications such as an Intel P55C

™ , AMD

K6

™ , as well as Cyrix 6X86L™ and the M2™ proces-

sors. Typically in these applications a dual supply regu-

lator converts 5V to 3.3V for I/O supply and a jumper

programmable supply of 1.25V to 3.5V for Core supply.

The linear regulator controller portion in the IRU3033 is a

programmable controller allowing flexibility for the I/O

regulator and has a minimum of 50mA drive current ca-

pability designed to provide ample current for an exter-

nal pass transistor. The IC uses an internal regulator

generated from the 12V supply to power the controller

as well as the 12V supply to drive the power MOSFET,

allowing a low cost N-channel MOSFET switch to be

used. The IC also includes an error comparator for fast

transient response, a precise voltage reference for set-

ting the output voltage as well as a direct drive of the

MOSFET for the minimum part count.

PACKAGE ORDER INFORMATION

Data Sheet No. PD94147

FEATURES

LDO Controller allows the use of a low cost pass

transistor for the I/O supply

8-Pin SOIC combines switching and linear

controller

Internal pre-regulator eliminates cross talk

between switching and linear regulators

Automatic shut down of the linear regulator when

connected to the Vcc2 detect pin

On-Board MOSFET Driver

Fastest transient response of any controller

method (0 to 100% Duty Cycle in 100ns)

1% Internal Voltage Reference

Internal Under-Voltage Lockout protects MOSFET

during start-up

Dual supply low voltage processor applications,

such as: P55C

™ , CYRIX M2™ , POWER PC™

and AMD K6

™

Simple 5V to 3.3V switcher for Pentium with AGP

or Pentium II

™ applications

APPLICATIONS

CPU

I/O

Vcc2 Det

Core

5V

5V

12V

Q1

C1

L1

C3

Q2

D1

C2

L2

R4

R5

C7

R6

R7

C6

R8

R3

C5

D2

R10

C8

R9

Drv1

Gnd

Drv2

IRU3033