DDR termination regulator in a 24-TSSOP exposed pad package
The LTC3618IFE#PBF is a DDR converter IC from Analog Devices designed specifically for DDR memory termination and tracking applications. It delivers two regulated outputs from an input range of 2.25V to 5.5V, making it compatible with both 2.5V and 5V rails common in DDR VDDQ supplies. The first output provides the VTT termination voltage, adjustable down to 0.6V, while the second output generates the VREF reference voltage. This dual-output architecture is standard for DDR1 through DDR4 memory systems where tight tracking between VTT and VREF is critical for signal integrity on the data bus.
Industrial temperature grade and package fit
Rated for -40°C to 125°C operating temperature, the LTC3618IFE#PBF is suited for industrial environments where ambient temperatures exceed commercial limits. The 24-TSSOP package with exposed pad (0.173" body width, 4.40mm) requires a thermal land pattern on the PCB to dissipate heat from the internal power FETs — the exposed paddle must be soldered to a copper plane for rated output current. The adjustable output down to 0.6V covers the VTT termination voltage for DDR3 (0.75V) and DDR4 (0.6V) standards. The input range from 2.25V to 5.5V means a single 3.3V or 5V rail can supply both the VDDQ and the converter, simplifying the power tree on a memory module or motherboard.