Low EMI DC/DC regulator to meet tightening standards

“The ARG81800 is at the forefront of technology,” explained Mark Gaboriault, Marketing Director at Allegro. “The features that we have added solve real-world challenges for our customers.”

EMI DC/DC regulator passes ‘airport test’

As electrical content in cars continues to increase, so does the continuous draw of keep-alive systems on the battery. Components must be able to pass the ‘airport test’, drawing as little current as possible so that the battery can still start the car after an extended period (such as a holiday). Similarly, battery operated industrial systems must limit battery drain to extend service period.

The ARG81800 DC/DC regulator draws just 8μA, from VIN while regulating 3.3V or 5.0 Vout at no load. In comparison to the typical ~100uA budgeted for automotive battery-powered subsystems, this low Iq solution frees up significant overhead to be allocated to other current draws that may occur in the system, allowing more design margin.

Passing EMC can be a time-consuming, expensive and frustrating process. With extremely low EMI, the ARG81800 is designed to make it easier to pass the first time around.

“The onus of passing EMC has historically been solely on our customer,” added Gaboriault. “We embraced the opportunity to offer solutions that make it easier for our customers to meet their EMC requirements, including reference designs and design notes.”

The ARG81800 is capable of wide switching frequency up to 2.4 MHz to avoid critical ‘keep out’ zones (e.g., the AM band), as well as frequency dithering and slew rate control to minimise switching noise. It also offers unique ‘dithering-on-sync’ CLKOUT, which can be used for other switching converters in the system. 

EMI DC/DC regulator designed for robustness

Pin opens and pin shorts happen, but they don’t have to ruin the entire board. Robust IC design in the ARG81800, including pin open/short and component faults, protects against IC and PCB damage during manufacturing and eliminates associated scrap costs.

The 150°C Tj operating capability makes the ARG81800 suitable for harsh underhood and industrial automation applications. A power-good output signal with rising-edge makes system power sequencing easier and provides diagnostic coverage.

The new features include:

• Ultra-low quiescent current mode.
• A 150°C operating temperature - for demanding automotive or industrial operating conditions.
• Pin open/short and component faults.
• Unique EMC reductions achieved by incorporating Spread Spectrum frequency modulation (dithering) to a non-dithered external SYNC clock as well as providing a dithered clock output to be used for other converters in the system.