DC2318A Analog Devices

DEMO MANUAL DC2318A LT3089EDF 800mA Rugged Linear Regulator with Monitors DESCRIPTION Demonstration circuit 2276A is an 800mA low dropout The output current monitor (I /5000) and die junction OUT rugged linear regulator featuring LT 3089. Key features of temperature output (1A/C) provide system monitoring the IC are the extended safe operating area (SOA), output and debug capability. In addition, a single resistor pro- current monitor, temperature monitor and programmable grams current limit. current limit. Internal protection circuitry includes reverse-battery and The LT3089 can be paralleled for higher output current reverse-current protection, current limiting and thermal or heat spreading. The device withstands reverse input limiting. DC2318A uses the LT3089EDF which is a 12-lead and reverse output-to-input voltages without reverse (4mm 4mm) plastic DF package with an exposed pad on current flow. the bottom-side of the IC for better thermal performance. The LT3089s precision 50A reference current source These features make DC2318A an ideal circuit for surface- allows a single resistor to program output voltage to mount power supply, rugged industrial power supply, low any level between zero and 34.5V. The current reference output voltage supply and post regulator for switching architecture enables load regulation to be independent of supplies. output voltage. The LT3089 is stable with or without input Design files for this circuit board are available at and output capacitors. DEMO MANUAL DC2318A QUICK START PROCEDURE Demonstration circuit 2318A is easy to set up to evalu- 3. Turn on the power at the V . IN ate the performance of the LT3089. Refer to Figure 1 for NOTE: Make sure that the V voltage does not exceed 36V. IN proper measurement equipment setup and follow the 4. Check for the proper output voltages: procedure below: NOTE: If there is no output, temporarily disconnect the load NOTE: When measuring the input or output voltage ripple, to make sure that the load is not set too high or is shorted. care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the input or output voltage 5. Once the proper output voltages are established, adjust ripple by touching the probe tip directly across the terminals the loads within the operating range and observe the out- of the input or output capacitors. See Figure 2 for proper put voltage regulation, efficiency and other parameters. scope probe technique NOTE: Make sure that the power dissipation is limited 1. Use JP1 to set the desired output voltage below the thermal limit. 2. With power off, connect the input power supply to V IN and GND. I IN + POWER V V LOAD IN OUT SUPPLY + + + + DC2318A F01 Figure 1. Test Procedure Setup Drawing for DC2276A V GND OUT Figure 2. Measuring Input or Output Ripple dc2318af 2