Description

The device PM6670 is a complete DDR2/3 power supply regulator designed to meet JEDEC specifications.

It integrates a Constant On-Time (C.O.T.) buck controller, a 2Apk sink/source Low Drop Out regulator and a 15mA low noise buffered reference.

The C.O.T. architecture assures fast transient response supporting both electrolytic and ceramic output capacitors. An embedded integrator control loop compensates the DC voltage error due to the output ripple.

Features switching

■ Switching section (VDDQ)

– 4.5V to 28V input voltage range

– 0.9V, ±1 voltage reference

– 1.8V (DDR2) or 1.5V (DDR3) fixed output voltages

– 0.9V to 2.6V adjustable output voltage

– 1.237V ±1 reference voltage available

– Very fast load transient response using constant on-time control loop

– No RSENSE current sensing using low side MOSFET’s RDS(ON)

– Negative current limit

– Latched OVP and UVP

– Soft start internally fixed at 3ms

– Selectable pulse skipping at light load

– Selectable No-Audible (33KHz) pulse skip mode

– Ceramic output capacitors supported

– Output voltage ripple compensation

■ VTT LDO and VTTREF

– 2Apk LDO with foldback for VTT

– Remote VTT sensing

– High-Z VTT output in S3

– Ceramic output capacitors supported

– ±15mA Low noise buffered reference

Applications

■ DDR2/3 memory supply

■ Notebook computers

■ Handheld and PDAs

■ CPU and chipset I/O supplies

■ SSTL18, SSTL15 and HSTL bus termination