The LTM4678 integrates a DC/DC controller, EEPROM, power FETs, inductors and supporting components

By Brian
Santo, contributing writer

Devices Inc.

(ADI) has been expanding its line of micromodule (µModule) regulators, introducing more than a half-dozen new models
this year. Its latest has a unique twist, though; the inductors of the LTM4678 are exposed on the surface of the BGA so that they’ll do double-duty as
heat sinks.

In April, the
company announced a particularly small, low-power module, the LTM4661.
This module is a step-up regulator that integrates only a few capacitors and a
single resistor. It occupies less than 1 cm² single-sided or 0.5 cm² on double-
sided PCBs. ADI has also begun marketing a set of other µModules
in various configurations.

The new Power by
Linear LTM4678 step-down
µModule regulator is integrated with a PMBus digital interface, designed for
digital management of power supplies.



By stacking and
exposing its two inductors on top of BGA package, the LTM4678 uses the
inductors as heat sinks to transfer heat from inside, keeping the device cool.
On-board EEPROM and PMBus I2C enables a user to measure, alter and
record parameters including voltage, load current, temperature and sequencing, ADI

include PCIe boards, communication infrastructure, cloud computing, optical as
well as medical, industrial and test and measurement devices.

The LTM4678 comes in two configurations: dual
25 A or single 50 A. ADI said that designers can group up to five of the
devices; they will current-share at 50 A each to deliver up to 250 A to loads
such as processors, FPGAs and ASICs.

The LTM4678 integrates
a DC/DC controller, EEPROM, power FETs, inductors and supporting components in
a 16-mm × 16-mm × 5.86-mm BGA package. ADI said it guarantees output voltage
accuracy of ±0.5% over line, load and temperature (-40°C to 125°C).

The LTM4678
operates from 4.5-V to 16-V input range, and the two output voltages are
digitally controlled from 0.5 V to 3.3 V. The switching frequency is 350 kHz to
1 MHz and can be synchronized to an external clock from 350 kHz to 1 MHz for
noise sensitive applications.

Available now, pricing
starts at $47.48
in quantities of 1,000.