QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1388A 3A QUIESCENT CURRENT, 20mA LINEAR REGULATOR LT3008EDC DESCRIPTION Demonstration circuit 1388A is an ultralow quiescent current and low dropout voltage linear regulator featuring LT(R)3008, which comes in an 8-lead TSOT23 or 2mmX2mm DFN package. The DC1388A has an input voltage range from 2V to 45V, and is capable of delivering up to 20mA output current. With the 3A quiescent current of the LT3008, the DC1388A is ideal for supplying power to low current batterypowered systems, keep-alive power supply and remote monitoring utility meters and hotel door locks. The LT3008 datasheet gives a complete description of the part, operation and application information. The datasheet should be read in conjunction with this quick start guide for working on or modifying the demo circuit 1388A. Design files for this circuit board are available. Call the LTC factory. , LTC and LT are registered trademarks of Linear Technology Corporation. Table 1. Performance Summary ( TA = 25oC ) PARAMETER CONDITION VALUE Minimum Input Voltage 2V Maximum Input Voltage 45V Output Voltage Vin=45V, Iout=20mA 1.2V 3% Vin=45V, Iout=20mA 1.5V3% Vin=45V, Iout=20mA 1.8V3% Vin=45V, Iout=20mA 2.0V3% Vin=45V, Iout=20mA 2.5V3% Vin=45V, Iout=20mA 3.3V3% Vin=45V, Iout=20mA 5.0V3% Maximum Output Current 20mA Quiescent Current <3A QUICK START PROCEDURE The DC1388A is easy to set up to evaluate the performance of the LT3008. Refer to Figure 1. for proper measurement equipment setup and following the procedures below: 1. Before proceeding to test, insert jumper JP1 into the OFF position, and use VOUT Select jumper J1 for the desired output voltage 1.2V, 1.8V, 2.0V, 2.5V, 3.3V or 5.0V. If the output voltage is different from the above values, use the USER option and install a resistor R8. Select R8 according to the following equation: R8 = VOUT -1 619K . 0.6V Assume 1.2V is the desired output for the following evaluations. 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1388A 3A QUIESCENT CURRENT, 20mA LINEAR REGULATOR 2. Apply 2V across Vin (to Gnd). Insert jumper JP1 into the ON position. Draw 20mA of load current. The measured Vout should be 1.2V 3% (1.164V to 1.236V). 3. Vary the input voltage from 2V to 45V and the load current from no load to 20mA. Vout should measure 1.2V 3% (1.164V to 1.236V). Figure 1. Proper Measurement Equipment Setup Figure 2. Measuring Input or Output Ripple 2 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1388A 3A QUIESCENT CURRENT, 20mA LINEAR REGULATOR 3