LX1669CD

LX1669CD Datasheet

LX1669

Part	Datasheet
LX1669CD	LX1669CD (pdf)

PDF Datasheet Preview
L I N D O C # 1669 LX1669 PROGRAMMABLE DC:DC CONTROLLER PR O D U C T I O N DATASHEET The LX1669 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 suitable for powering II and other processors. Programmable Synchronous Rectifier Driver for CPU Core. The main output is adjustable from to 3.5V using a TTL-compatible 5-bit digital code to meet Intel specifications. The IC can read the signal from a DIP-switch, hardwired to Pentium II processor’s pins or from software. The 5-bit code adjusts the output voltage between and 2.05V in 50mV increments, and between and 3.5V in 100mV increments. The device can drive dual MOSFET’s resulting in typical efficiencies of 85 90%, even with loads in excess of 10A. Short-circuit Current Limiting without Expensive Current Sense Resistors. The current sensing mechanism can use a PCB trace resistance or the parasitic resistance of the main inductor. For applications requiring a high degree of accuracy, a conventional sense resistor can be used. Ultra-Fast Transient Response Reduces System Cost. The fixed frequency modulated off-time architecture results in the fastest transient response for a given inductor. Small Package Size. The LX1669 is available in an economical 16-pin narrow body SOIC package. NOTE For current data & package dimensions, visit our web site: KEY FEATURES s 5-Bit Programmable Output For CPU Core Supply s Power Solution For Pentium II Processors s No Sense Resistor Required For Short-Circuit Current Limiting s Soft-Start And Hiccup-Mode Current Limiting Functions s Modulated Constant Off-Time Control Mechanism For Fast Transient Response And Simple System Design s Power Good Flag s Over-Voltage Pin Can Drive SCR Crowbar Or Turn Off Signal Silver-Box Power Supply s Digital-Compatible Inputs Including VID Pins A P L I C AT I O N S s Socket 7 Processor Supplies s Pentium II Processor Supplies s Deschutes CPU & L2-Cache Memory Supplies s Voltage Regulator Modules s General Purpose And Microprocessor DC:DC Supplies 1µF 1µF PWRGD PRODUCT HIGHLIGHT 1 TDRV 2 VCC12 3 VCC5 4 PWRGD 5 OVP 6 VID0 7 VID1 8 VID2 LX1669 L2, 1µH IRL3102 PGND 16 BDRV 15 AGND SS/EN 14 13 VFB 12 0.1µF VCORE 11 VID4 10 VID3 9 VID4 VID3 VID2 VID1 VID0 1500µFx3 RSENSE 2.5µH IRL3303 2N6504

PDF Datasheet Preview

L I N D O C # 1669

LX1669

PROGRAMMABLE DC:DC CONTROLLER PR O D U C T I O N DATASHEET

The LX1669 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 suitable for powering II and other processors.

Programmable Synchronous Rectifier Driver for CPU Core. The main output is adjustable from to 3.5V using a TTL-compatible 5-bit digital code to meet Intel specifications. The IC can read the signal from a DIP-switch, hardwired to Pentium II processor’s pins or from software. The 5-bit code adjusts the output voltage between and 2.05V in 50mV increments, and between and 3.5V in
100mV increments. The device can drive dual MOSFET’s resulting in typical efficiencies of 85 90%, even with loads in excess of 10A.

Short-circuit Current Limiting without Expensive Current Sense Resistors. The current sensing mechanism can use a PCB trace resistance or the parasitic resistance of the main inductor. For applications requiring a high degree of accuracy, a conventional sense resistor can be used.

Ultra-Fast Transient Response Reduces System Cost. The fixed frequency modulated off-time architecture results in the fastest transient response for a given inductor. Small Package Size. The LX1669 is available in an economical 16-pin narrow body SOIC package.

NOTE For current data & package dimensions, visit our web site:

KEY FEATURES
s 5-Bit Programmable Output For CPU Core Supply
s Power Solution For Pentium II Processors s No Sense Resistor Required For Short-Circuit

Current Limiting s Soft-Start And Hiccup-Mode Current

Limiting Functions s Modulated Constant Off-Time Control

Mechanism For Fast Transient Response And Simple System Design s Power Good Flag s Over-Voltage Pin Can Drive SCR Crowbar Or Turn Off Signal Silver-Box Power Supply s Digital-Compatible Inputs Including VID Pins

A P L I C AT I O N S
s Socket 7 Processor Supplies s Pentium II Processor Supplies s Deschutes CPU & L2-Cache Memory

Supplies s Voltage Regulator Modules s General Purpose And Microprocessor

DC:DC Supplies
1µF
1µF

PWRGD

PRODUCT HIGHLIGHT
1 TDRV
2 VCC12 3 VCC5 4 PWRGD
5 OVP 6 VID0 7 VID1 8 VID2

LX1669

L2, 1µH

IRL3102

PGND 16

BDRV 15

AGND SS/EN
14 13

VFB 12 0.1µF VCORE 11 VID4 10

VID3 9

VID4 VID3 VID2 VID1 VID0
1500µFx3

RSENSE
2.5µH

IRL3303
2N6504

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Datasheet ID: LX1669CD 648554