Demonstration circuit 2362A is an adjustable 3A linear regulator featuring the LT3033. The LT3033 is a very low dropout voltage (VLDO™) linear regulator that operates from a single input supply down to 0.95V. The device supplies 3A output current with 95mV typical dropout voltage. The LT3033 is ideal for low input voltage to low output voltage applications, providing comparable electrical efficiency to a switching regulator.
The LT3033 optimizes stability and transient response with low ESR ceramic output capacitors as small as 10µF. A 10nF bypass capacitor at REF/BYP pin typically reduces output voltage noise to 60µVRMS in a 10Hz to 100kHz bandwidth. Soft-start time is directly proportional to the REF/BYP capacitor value.
The LT3033’s current limit, accurate to ±12% over a wide input voltage and temperature range, can be programmed by a single resistor. When the input-to-output differential voltage exceeds 5V, foldback current limit lowers the internal current limit level, which may override the external programmable current limit.
LT3033 has a PWRGD pin which indicates when the ADJ pin is within 8% of its nominal value. By connecting an external pull-up resistor from PWRGD to either the IN or OUT pin, PWRGD is pulled low when the output falls below 90.1% of the regulated voltage. As the output voltage rises above 92% of its regulated voltage, the PWRGD pin voltage is pulled up.
The LT3033 features output current monitoring by connecting a resistor from the IMON pin to GND. The IMON pin is the collector of a PNP current mirror that outputs 1/2650th of the power PNP current. This circuitry is active for VIMON ≤ (VOUT – 400mV).
The LT3033 also features shutdown, reverse-battery protection, thermal limiting with hysteresis and reverse current protection.
The LT3033 is available as an adjustable device with an output voltage down to the 200mV reference. The device is available in a thermally enhanced, low profile 3mm × 4mm × 0.75mm QFN package.
The LT3033 data sheet gives a complete description of the part, operation and application information. The data sheet must be read in conjunction with this quick start guide for demo circuit 2362A.
Pricing displayed is based on 1-piece.
Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.