ISL6530

Features:

•Provides VDDQ, VREF, and VTTvoltages for one- and two-channel DDRAM memory systems
•Excellent voltage regulation
-VDDQ= 2.5V ±2% over full operating range
-VREF= (VDDQ÷2) ±1% over full operating range
-VTT= VREF± 30mV
•Supports 'S3' sleep mode
-VTTis held at VDDQ÷2 via low power window regulator to minimize wake-up time
•Fast transient response
-Full 0% to 100% duty ratio
•Operates from +5V input
•Overcurrent fault monitor on VDD
-Does not require extra current sensing element
-Uses MOSFET's rDS(ON)
•Drives inexpensive N-Channel MOSFETs
•Small converter size
-300kHz fixed frequency oscillator
•24 Lead, SOIC or 32 Lead, 5mm*5mm QFN
•Pb-Free Available (RoHS Compliant)




Application

•VDDQ, VTT, and VREF regulation for DDRAM memory systems
-Main Memory in AMD® Athlon™ and K8™, Pentium®
III, Pentium IV, Transmeta, PowerPC™, AlphaPC™, and
UltraSparc® based computer systems
-Video memory in graphics systems
•High-power tracking DC-DC regulators




Pinout






Specifications

Supply Voltage, V_CC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7.0V
Boot Voltage, V_BOOTn- V_PHASEn. . . . . . . . . . . . . . . . . . . . . . +7.0V
Input, Output or I/O Voltage. . . . . . . . . . . . . . . . . . .GND -0.3V to V
CC+0.3VESD Classification. . . . . . . . . . . . . . . . . . . . . . . . . .Class 2




Description

The ISL6530 provides complete control and protection for dual DC-DC converters optimized for high-performance DDRAM memory applications. It is designed to drive low cost N-channel MOSFETs in synchronous-rectified buck topology to efficiently generate 2.5V VDDQ for powering DDRAM memory, VREF for DDRAM differential signalling, and VTT for signal termination. The ISL6530 integrates all of the control, output adjustment, monitoring and protection functions into a single package. The VDDQ output of the converter is maintained at 2.5V through an integrated precision voltage reference. The Vsub>REF output is precisely regulated to 1/2 the memory power supply, with a maximum tolerance of 1% over temperature and line voltage variations. VTT accurately tracks Vsub>REF. During V2_SD sleep mode, the VTT output is maintained by a low power window regulator. The ISL6530 provides simple, single feedback loop, voltagemode control with fast transient response. It includes two phase-locked 300kHz triangle-wave oscillators which are displaced 90o to minimize interference between the two PWM regulators. The regulators feature error amplifiers with a 15MHz gain-bandwidth product and 6V/s slew rate which enables high converter bandwidth for fast transient performance. The resulting PWM duty ratio ranges from 0% to 100%. The ISL6530 protects against over-current conditions by inhibiting PWM operation. The ISL6530 monitors the current in the VDDQ regulator by using the rDS(ON) of the upper MOSFET which eliminates the need for a current sensing resistor.