LX1668

Features:

5-Bit Programmable Output For CPU Core Supply
Internal Fixed 2.5V Low Dropout Regulator
Adjustable Linear Regulator Driver
Complete Single-Chip Power Solution For Pentium II Processors
No Sense Resistor Required For Short-Circuit Current Limiting
Soft-Start And Hiccup-Mode Current Limiting Functions
Modulated Constant Off-Time Control Mechanism For Fast Transient Response And Simple System Design
Power Good Flag
Over-Voltage Pin & SCR
Digital-Compatible Inputs (Including VID Pins)
Output Disable Function Shuts Off PWM While Keeping 2.5V LDO Active - Compatible With "Green PC" And "Instant On" Requirements
Compatible to VRM8.2 - 8.4 Specifications


Application

Pentium II & Pentium III Processor Supplies
Voltage Regulator Modules
General Purpose And Microprocessor DC:DC Supplies


Pinout




Specifications

12V Supply Voltage (VCC12) ............................................................................. 18V
5V Supply Voltage (VCC5) ...................................................................................7V
Supply Voltage (Internal LDO)/(VCC3) ..................................................................7V
Output Drive Peak Current Source (500ns)....................................................... 1.0A
Output Drive Peak Current Sink (500ns) ...........................................................1.0A
Input Voltage (SS, VID[0:4]) ................................................................. -0.3V to 6V
Operating Junction Temperature .................................................................... 150
Storage Temperature Range .......................................................... -65 to +150
Lead Temperature (Soldering, 10 Seconds) .................................................... 300





Note 1. Exceeding these ratings could cause damage to the device. All voltages are with respect to Ground. Currents are positive into, negative out of the specified terminal.
Note 2. VCC3 supply is used as input to internal low dropout regulator. Voltages above 3.3V will cause increased thermal dissipation in the package. Power dissipation should be limited to keep junction temperature below maximum rating.

Description

The LX1668 is a Monolithic Switching Regulator Controller IC designed to provide a low cost, high performance adjustable power supply for advanced microprocessors and other applications requiring a very fast transient response and a high degree of accuracy. It provides a programmable switching regulator output, together with one internal linear low dropout regulator and one adjustable linear regulator driver. The LX1668 offers a triple-output single-chip power supply for Pentium® II and other processors.