45V, 500mA LDO has low noise of 25 µVRMS

January 28, 2014 // By Graham Prophet
Linear Technology’s LT3065 is a high voltage, low noise, low dropout voltage linear regulator offering precision, programmable current limit and a power-good flag. The device delivers up to 500 mA output current with a 300 mV dropout voltage at full load.

The regulator has a 1.8V to 45V input voltage range and output voltage is adjustable from 0.6V to 40V. A single REF/BYP pin capacitor provides low noise operation-only 25 µVRMS across a 10 Hz to 100 kHz bandwidth, and also reference soft-start functionality, preventing output voltage overshoot at turn-on. Output voltage tolerance is ±2% over line, load and temperature.

The LT3065 operates with a very small, low cost, 3.3 µF ceramic output capacitor, optimising stability and transient response: a PWRGD flag indicates output regulation. One resistor programs the external precision current limit (±10% over temperature). Internal protection circuitry includes reverse-battery protection, reverse-output protection, reverse-current protection, current limit with foldback, and thermal limiting. The device’s wide input and output voltage ranges, fast transient response, low quiescent current of 55 µA (operating) and <1 µA (in shutdown) make it a suitable choice for industrial power supplies, avionic power supplies, automotive power supplies, battery-powered systems and instruments requiring optimum run time, and high reliability power supplies requiring more extensive protection.

The LT3065 is available in thermally enhanced 10-lead 3 x 3 mm DFN and 12-lead MSOP packages, both with a compact footprint. The E- and I-grade have an operating junction temperature of -40°C to +125°C, H grade is rated from -40°C to +150°C, and the MP-grade version is specified from -55 to +150°C. Pricing starts at $1.85 (1000).

Linear Technology; www.linear.com/product/LT3065