Inside the unit (Figure 7) is a superb, clean mechanical layout. A 2-mm thick aluminium chassis holds the main double-sided PCB which sits along the bottom of the case. The board uses SMD components which populate both sides of the board. Behind the front panel is a PCB which interfaces to the display and pushbuttons. The chassis extends up at the rear to form the instrument back panel.

  There are no nuts to work loose and cause problems. With the unit open we can see on the upper level, a panel holding a fan and a third-party, industry standard, open-frame 200- watt AC/DC, switched-mode supply unit. This unit supplies 48 V DC to the lower PCB where it divides into three microcontroller (Microchip dsPIC DSC’s) controlled DC/DC switching regulators for outputs to the front and rear panels. The PCB quality, component mounting and layout are second to none. With the front panel power switched off the main AC/DC power supply remains continually powered in standby mode until the PSU is turned off at the rear switch. In standby the unit uses just over 8 W.

How does it stack up?

Considering the high build quality and technical sophistication of the HMC8043 it’s remarkable that little effort been put into the instrument documentation. On querying Rohde & Schwarz I was happy to hear though that the issue is being worked on. With all its connectivity options the HMC8043 is perfectly suited to a fully automated test environment but as we saw it also works well as a general purpose bench top power supply for use in the lab. If you are looking for a low-noise bench supply with excellent transient response a traditional standard, heavy, linear design is still hard to beat. If however you want something that can be used in an automated test environment and is programmable, lightweight, versatile and efficient with the ability to control the output to within millivolts and milli- ampères then the superbly built Rohde & Schwarz HMC8043 has plenty to offer.