To reduce development time and cost for PCs and peripherals, Cypress Semiconductor Corp. has added field programmability to its family of spread-spectrum clock generators.
A new device, unveiled last week, offers the same systemic electromagnetic interference (EMI)-reducing benefits as Cypress' existing CyberClock spread-spectrum clock chips, but gives customers the ability to configure samples on the fly, said Cavit Ozdalga, marketing manager for the company's Timing Technology Division in San Jose.
"EMI is verified at the end of a project, not the beginning, and the customer usually has only a few days to go into production," Ozdalga said. "We can give them blank parts, and they can program them in minutes while testing products in the EMI chamber."
Cypress is offering a $200 programming kit, which can be used with any desktop or notebook PC that has a power connection and a parallel port. The kit includes a GUI-driven tool by which users select clock frequency and modulation values, then download the data into the clock chip, a process that takes about five minutes, according to Ozdalga.
Use of the tool requires one-time registration on Cypress' Website, which allows the company to assign the customized configuration a part number and store the design file so that, when production parts are needed, the customer can order them online.
The CY25100 supports input frequencies from a crystal or other reference from 8 to 166MHz, and output frequencies from 3 to 200MHz. To reduce EMI, frequency modulation can be programmed over a down spread range of 0.5% to 5%, and a center spread range of 0.25 to 2.5. Up to 20dB EMI reduction can be achieved using a worst-case harmonic, the company said.
While EMI reduction is the main target of the spread-spectrum clock generator, the cost savings from being able to use less expensive components around it can also be significant, Ozdalga said. For example, reducing EMI can allow a low-end inkjet printer to replace a four- or six-layer PCB with a two-layer board, on which longer trace lengths would ordinarily produce higher EMI emissions.
"Twenty percent of the applications we're in are not just because a customer has an EMI problem, but to reduce the number of PCB layers, which is a considerable cost advantage," he said. "Another big saving comes from the wide frequency output. Instead of using a 100- MHz crystal oscillator to generate high frequencies, you can use a single inexpensive crystal--whatever you already have on the shelf--while getting also the benefit of EMI reduction."
The CY25100 is available in 8-pin TSSOPs and SOICs, priced from $1.55 to $1.75 in 1,000s.