Not long ago, 400-W dc power supplies were considered compact if they took up just two rack spaces—and if only two people were required to lift them, install them, or remove them from a rack. Now the race is on to require less space, efficiently deliver more power, trim costs, and eliminate back pain.

TDK-Lambda’s Z+ series programmable dc 400-W components set a benchmark first for freeing up bench and rack space (see the figure). The units are 33% smaller and 40% lighter than Lambda’s previous generation, the ZUP series, as well as comparable components on the market.

TDK-Lambda’s Z+ series 400-W, programmable benchtop and rack-mountable dc power supplies are 33% smaller and 40% lighter than previous ZUP series components.

These high-density, high-efficiency, 2U format, benchtop and rack-mountable supplies are designed for an array of automated test equipment (ATE), laboratory, and OEM applications such as test and measurement, semiconductor burn-in, LED/laser testing, RF amplifiers, and electromagnetic and electrochemical applications.

Delivering 400 W of output power with an output voltage range from 0 to 100 V dc and output currents up to 40 A, the Z+ series also represents a 49% increase in power density over the previous generation. Standard models in the series measure 3.27-in. high and 2.76-in. wide, allowing for the installation of as many as six units in a 19-in. rack.

Higher power is achieved by connecting Z+ units in parallel with active current sharing.  In master/slave parallel configurations, the master unit reports total system output current, meaning all units appear as a single power supply to the remote controller. Users can connect up to two Z+ supplies in series to boost output voltage or create bipolar outputs.

All Z+ series models operate in either a constant-current or constant-voltage mode from an 85-V ac to 265-V ac input. They provide active power factor correction, variable-speed fans, plus user-selectable safe start and auto-restart. Safe start returns the supply to its last settings after power interruption, but with the output disabled. Auto restart resumes normal supply operation without intervention after a power interruption.

The Z+ programmable power supplies offer a wealth of extra features that extend their viability for diverse applications. These include separate, four-digit volt/current displays, arbitrary-function generation, six storable pre-programmed functions, output sequencing, two programmable output pins, and USB, RS-232, and RS-485 interfaces.

Options for the series include other digital and isolated analog interfaces including an LXI Class C compliant local-area network (LAN) interface, a 19-in. rack with blanking plates for unused slots, assorted options for front panel output-jacks, and multiple-unit housings for bench-top applications. Pricing starts at $1460 each.

A datasheet is available at Application notes and user manuals are available at