Wide input voltage buck converter for USB type-C transceivers

April 13, 2016 // By Graham Prophet
In battery-powered applications, Maxim Integrated’s MAX77596 allows always-on operation; designers of USB Type-C small form factor devices can now create always-on rails with the ultra-low quiescent current converter.

Next-generation products that exploit the high data rates and increased power transfer capability of USB Type-C ports will require low-voltage supply rails to power necessary Type-C port controllers. Devices utilising the Power Delivery (PD) voltage range (5V to 20V) can now generate an always-on (1.8V/3.3V/5.0V) digital supply rail for the controller. 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.

Portable gadgets—such as tablets, notebooks, cameras, and drones—can evolve to Type-C with PD using the MAX77596 power supply. Previously, engineers 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, low quiescent current, and compact TDFN package that results in reduced design time and smaller solution size compared to a two-chip solution.


The 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 300 mA DC loads. It has short-circuit and thermal protection, 6.67 msec internal soft-start minimising inrush current, current-mode control architecture, and up to 42V input voltage tolerance.


An ultra-low quiescent current of 1.1 µA permits always-on operation; the device comes in a 2.0 x 2.5 x 0.75 mm 10-pin TDFN package; it offers line transient response of 50mVpp output shift when changing from 5V to 20V and back.


Maxim Integrated; www.maximintegrated.com