Bench Talk

Join journalist Tommy Cummings for a weekly look at all things interesting, new, and noteworthy for design engineers.

Remember when we griped about the static on AM radio? Now, it's the car's turn to gripe about the static.

Modern vehicles have a lot more on their plate than the era of AM-only radio reception with knobs and push-buttons. Today, the automotive electrical environment has a lot going on, with several applications being electromagnetic interference (EMI) sensitive.

This means deploying switching regulators that limit the noise and don't exacerbate EMI concerns for design engineers. Switching regulators are typically the first active component on the input power bus line. No matter the downstream converters, an effective switching regulator impacts overall converter EMI performance. Minimizing EMI is a thing.

Before, the solutions were EMI shielding boxes or slowing the switching edges of the internal MOSFET. These solutions weren't practical in footprint size or had limited efficiency.

But new power integrated circuit designs have been developed to enable faster switching frequencies, higher efficiency, and lower minimum on-times.

These innovations keep design engineers on their toes. And it's why this week's New Tech Tuesdays examines three products designed for low-EMI operation.

Texas Instruments LMQ62440-Q1 Synchronous Step-Down Converter is specifically designed for minimal EMI. The converter's wide-input, synchronous peak-current mode buck regulator is ideal for various automotive applications. The device can operate over a range of switching frequencies, including the sub-AM band at 400kHz and above the AM band at 2.1MHz. The device also has low unloaded current consumption, which is suitable for off-battery, always-on applications. Operating at 2.1MHz also allows the use of small passive components. The converter itself is 4mm x 3.5mm in a VQFH-HR, 14-pin package.

Analog Devices Inc. LTC3310S Synchronous Step-Down Silent Switcher^® 2 DC-DC Converter achieves low EMI and high efficiency at switching frequencies as high as 5MHz. The device can provide up to 10A output current from a 2.25V to 5.5V input supply, all in a compact 3mm x 3mm LQFN package. It's ideal for automotive applications, servers, telecom power supplies, and more. LTC3310S also includes a power good signal when the output is in regulation, output overvoltage protection, thermal shutdown, a temperature monitor, clock synchronization, mode selection, and output short circuit protection.

Maxim Integrated MAX25431 Automotive H-Bridge Buck-Boost Controller features V_IN ranges from 6V to 36V, which allows operation in cold-crank conditions while using only 55µA quiescent current at no load. Combined with its ability to maintain constant output voltage during battery transients, it is ideal for automotive applications. Its low quiescent current helps designers meet the original equipment manufacturer's current requirements—all in a 4mm x 4mm 24-pin SWTQFN package.

Today's modern automobiles have the same basic design: a chassis and four wheels. But inside these rolling machines are smaller, even micro, devices that maintain the operation of an ever-growing ecosystem of electronic systems. Design engineers must address this electrical environment with solution devices that include noise-limiting switching regulators and EMI-sensitive applications. Indeed, we've come a long way when it comes to dealing with static.