DEMO MANUAL DC687A LT3020 100mA, Low Voltage, Very Low Dropout Linear Regulator DESCRIPTION Demonstration circuit 687A is a low input voltage and ultra- The LT3020 data sheet gives a complete description of low dropout voltage supply using the LT 3020 linear regula- the part, operation and applications information. The tor, which comes in a small 8-lead DFN package. The DC687A data sheet must be read in conjunction with this demo has an input voltage range from 1V to 10V, an output voltage manual for demonstration circuit DC687A. The LT3020 range between 0.2V and 10V minus the dropout voltage, is assembled in an 8-lead MSOP and 3mm x 3mm DFN and is capable of delivering 100mA max. Due to the 0.2V packages with an exposed pad on the bottom-side of the reference of the LT3020, the DC687A is capable of supply- IC. Proper board layout is essential for maximum thermal ing power to very low voltage applications, such as (rela- performance. tively) high current voltage references. DC687A uses ceramic Design files for this circuit board are available. capacitors because of the LT3020 s ability to maintain stabil- All registered trademarks and trademarks are the property of their respective owners. ity even with the low ESR of ceramic output capacitors. PERFORMANCE SUMMARY Specifications are at T = 25C A PARAMETERS CONDITIONS MIN TYP MAX Input Voltage Range (V ) I = 100mA, V = 3.3V 1.05V 10V IN OUT OUT Output Voltage (V ) (JP2 in 1V Position) V = 1.3V, I =100mA 0.96V 1V 1.04V OUT IN OUT QUICK START PROCEDURE The DC687A is easy to set up to evaluate the performance of 1.5V, or 1.8V. Re-insert jumper JP1 into the ON position. the LT3020. For proper measurement equipment configura- Just as in the 1V out test, the output voltage should read tion, set up the circuit according to the diagram in Figure1. V 2% tolerance under static line and load conditions, OUT and 4% tolerance under dynamic line and load conditions. Please follow the procedure outlined below for proper operation. 5. When finished evaluating, insert jumper JP1 into the OFF position. 1. Before proceeding to test, insert jumper JP1 into the OFF position, and insert jumper JP2 into the 1V option. 6. WARNING: If long leads are used to power the demo circuit, the input voltage at the part could ring. This 2. Apply 1.3V across V (to GND). Insert jumper JP1 into IN ringing could affect the operation of the circuit or the ON position. Draw 10mA of load current. Measure even exceed the maximum voltage rating of the IC. To V it should be 1V 2% (0.98V to 1.02V). OUT eliminate this, insert a small tantalum capacitor (for 3. Vary the input voltage from 1.3V to 10V and the load instance, an AVX part TAJW226M010R) on the pads current from no load to 100mA. V should measure between the input power and return terminals on the OUT 1V 4% (0.96V to 1.04V). bottom of the demo board. The (greater) ESR of the tantalum will dampen the (possible) ringing voltage 4. Insert jumper JP1 into the OFF position and move jumper due to the use of long input leads. On a normal, typical JP2 into any of the remaining output voltage options: 1.2V, PCB, with short traces, the capacitor is not needed. Rev. 0 1DEMO MANUAL DC687A QUICK START PROCEDURE Figure1. Test Procedure Setup Drawing for DC687A Rev. 0 2