Description

The device PM6670S is a complete DDR2/3 power supply regulator designed to meet JEDEC specifications.

It integrates a constant on-time (COT) buck controller, a 2 Apk sink/source low drop out regulator and a 15 mA low noise buffered reference.

The COT 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 section (VDDQ)

– 4.5 V to 28 V input voltage range

– 0.9 V, ±1 voltage reference

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

– 0.9 V to 2.6 V adjustable output voltage

– 1.237 V ±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 3 ms

– Selectable pulse skipping at light load

– Selectable no-audible (33 kHz) pulse skip mode

– Ceramic output capacitors supported

– Output voltage ripple compensation

■ VTT LDO and VTTREF

– 2 Apk LDO with foldback for VTT

– Remote VTT sensing

– High-Z VTT output in S3

– Ceramic output capacitors supported

– ±15 mA 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