Wide input buck converter powers USB Type-C transceivers

Louise Smyth

Designers of USB Type-C small form factor devices can now create always-on rails with the ultra-low quiescent current MAX77596 buck converter from Maxim Integrated Products, writes Nick Flaherty.

Type-C USB connectors are enabling products with high data rates and increased power transfer capability that require low-voltage supply rails to power the port controllers. Devices using the Power Delivery (PD) voltage range (5V to 20V) specified in USB Type-C can now generate an always-on digital supply rail for the controller at 1.8V, 3.3V or 5V using the MAX77596. Operating from a supply as low as 3.5V and as high as 24V, the MAX77596 step-down converter can regulate from traditional 5V USB power as well as the 20V upper-end of the PD range and has a transient line response of 50mVpp output when changing from 5V to 20V and back.

This means portable equipment such as tablets, notebooks, cameras and drones can easily evolve to Type-C with PD using the flexible MAX77596power supply. Previously, customers designing in a power supply for USB Type-C port controllers had to compromise on either input voltage range, quiescent current, or size. A two-chip solution would often be required—a low input voltage linear regulator in parallel with a higher input voltage switcher to cover the wide voltage range of the PD standard. The MAX77596 has a combination of wide input voltage range from 3.5V to 24V and a low quiescent current of 1.1μA that provides always-on operation. The compact 10-pin TDFN package measures 2.0mm x 2.5mm x 0.75mm and results in reduced design time and smaller solution size compared to a two-chip solution and operates across the -40°C to +85°C temperature range.

The MAX77596 buck converter offers fixed 3.3V and 5V-output versions, and an adjustable version that allows users to program the output voltage between 1V and 10V with a resistor-divider. The converter can support up to 300mA DC loads. The MAX77596 is a robust IC with short-circuit and thermal protection, 6.67ms internal soft-start minimizing inrush current, proven current-mode control architecture, and up to 42V input voltage tolerance.

“The MAX77596 simplifies the design process for customers because they can now use one chip instead of two,” said Samay Kapoor, Senior Business Manager, Mobility Power at Maxim Integrated. “The MAX77596 also helps engineers minimize power consumption and extend battery life for the end application.”