What this LDO brings to the rail
The Maxim Integrated MAX1659ESA+ is a positive-output, single-channel LDO regulator that handles up to 350 mA with a maximum input of 16.5 V. Its output is adjustable from 1.25 V up to 16 V, and it also offers a fixed 5 V option — the part ships configured for adjustable use, but the 5 V fixed tap is available internally. The 8-SOIC package is surface-mount, rated for the -40°C to 85°C industrial temperature range, making it a candidate for outdoor telecom, factory-floor sensors, and engine-bay electronics where a clean local rail is needed.
Key ratings and what they mean for your BOM
The 350 mA output current sets the load budget. Maximum dropout is 0.875 V at 350 mA.
Output voltage: adjustable or fixed?
The part is listed as adjustable output with a fixed 5 V option. In practice, the adjustable version uses an external resistor divider from the output to the ADJ pin to set any voltage between 1.25 V and 16 V. If you want the fixed 5 V output, the internal divider is already trimmed — just connect the ADJ pin to ground. The control feature is an Enable pin for on/off control, useful for sequencing or power-saving shutdown.