Micro-module regulator for DDR/QDR4 SRAM runs from 3.3 to 15V

April 15, 2016 // By Graham Prophet
LTM4632 is a triple output micro-module (µModule, or power module) regulator for powering all three voltage rails of the new QDR4 and older DDR SRAM: VDDQ, VTT and VTTR (or VREF). Housed in an ultrathin LGA package (6.25 x 6.25 x 1.82 mm), the LTM4632 can be soldered on the backside of the PCB, and with one resistor and three capacitors it occupies only 0.5 cm² (dual-sided) or 1cm² (single-sided).

Capable of delivering 3A VDDQ and ±3A VTT (=1/2*VDDQ) two LTM4632s in parallel can provide up to 6A per rail for larger memory banks. For more than 6A VDDQ, the LTM4632 can be configured with the LTM4630 to provide between 18A and 36A VDDQ for very large arrays of SRAMs. If VDDQ is already available, the LTM4632 can be configured to supply a two-phase single VTT output up to 6A.


The LTM4632 can operate from a low input supply of 3.3V, as well as standard 5V and 12V inputs (up to 15V). Each of the two output voltages (VDDQ and VTT) range from 0.6V to 2.5V. The third output is a low noise 10 mA buffered output for VTTR of the SRAM. Applications include PCIe, cloud-based systems, RAID, video processing and networking using these SRAMs: DDR/DDR-II/DDR-III/DDR4/QDR/QDR-II/QDR-II+ and QDR4.


The LTM4632 contains a triple output DC/DC regulator, divide by 2 circuit, power switches, inductors and support components in a compact, ultrathin package. The LTM4632 is rated for operation from -40°C to 125°C. Pricing starts at $7.35 each for E-grade and $8.09 each for I-grade (1000).


Linear Technology; www.linear.com/product/LTM4632