You need to test, we're here to help.

You need to test, we're here to help.

24 April 2017

Testing the DDR Memory Interface's Physical Layer (Part III)

For analysis purposes. it's critical to separate read and write bursts of interest
Figure 1: For analysis purposes. it's critical to separate
read and write bursts of interest
Last time around, we began examining some of the challenges that come with testing the DDR interface's physical layer. In that post, we concentrated on getting to the devices' physical connections by various means including interposers, backside vias, and DIMM series resistors. Now, presuming we've managed to gain access to the DDR's ball-grid array, the next hurdle is separation of read and write bursts.

11 April 2017

Testing the DDR Memory Interface's Physical Layer (Part II)

A typical BGA package for DDR memory
Figure 1: Shown is a typical BGA
package for DDR memory
In the first of this series of posts, we undertook a high-level view of physical test of a DDR memory interface. Moving forward, let's look into some of the specific challenges one faces in a close examination of these interfaces.

05 April 2017

Testing the DDR Memory Interface's Physical Layer (Part I)

Clock, strobe, and data are three critical signals in DDR test
Figure 1: Clock, strobe, and data are
three critical signals in DDR test
In an earlier post, we took a brief tour through what constitutes a DDR memory interface: clock, command, address, and strobe+data lines linking a memory controller and an array of DRAM memory ICs. Next, we'll examine what DDR interface testing is all about, concentrating primarily on the physical layer.

29 March 2017

Fundamentals of the DDR Memory Interface

A representative test setup for physical-layer DDR testing
Figure 1: A representative test setup
for physical-layer DDR testing
Double data-rate (DDR) memory has ruled the roost as the main system memory in PCs for a long time. Of late, it's seeing more usage in embedded systems as well. Let's look at the fundamentals of a DDR interface and then move into physical-layer testing (Figure 1).

20 January 2017

Back to Basics: Three-Phase Sinusoidal Voltages

Three-phase AC voltages consist of three voltage vectors
Figure 1: Three-phase AC voltages
consist of three voltage vectors
In a previous post, we briefly covered the basics of single- and three-phase AC power systems. Single-phase systems, as we've noted, comprise a single voltage vector with a magnitude (in VAC) and a phase angle. Of course, a three-phase voltage consists of three voltage vectors and three phase angles. This installment will go on to describe three-phase AC voltages in similarly brief fashion.