LTC3632EDD LTC3632 DC1507A EEU-FC2A680L F/100V

HIGH EFFICIENCY 20MA MONOLITHIC SYNCHRONOUS BUCK REGULATOR LTC3632EDD DESCRIPTION Demonstration circuit 1507A is a high

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1507A HIGH EFFICIENCY 20MA MONOLITHIC SYNCHRONOUS BUCK REGULATOR LTC3632EDD LTC3632EDD DESCRIPTION Demonstration circuit 1507A is a high efficiency stepdown DC/DC converter featuring LTC3632EDD LTC3632EDD with internal high side and synchronous power switches that draws only 12µA quiescent current. It has a wide 4.5V to 50V input range and internal over voltage monitor capable of protecting the part through 60V surges. The jumper selectable output is up to 5V. LTC3632EDD LTC3632EDD can supply up to 20mA load current with a programmable peak current limit that provides a simple method for optimizing efficiency in lower current applications. With no compensation required, LTC3632EDD LTC3632EDD is easily configured with minimal components. Design files for this circuit are available. Call the LTC Factory. LTC is a trademark of Linear Technology Corporation Table 1. Performance Summary (TA = 25° C) PARAMETER CONDITION VALUE Input Voltage Range VIN Output Voltage VOUT 4.5V to 50V IOUT=1mA to 20mA, VIN=10V Maximum Output Current VOUT ± 2.7% (LTC3632 LTC3632 Output adjustable version) 20mA DC Supply Current Active Mode, VIN=10V, IO=0A 125µA Nominal Switching Frequency Inductance=1000µH, VIN=30V 60kHz QUICK START PROCEDURE The DC1507A DC1507A is easy to set up to evaluate the performance of the LTC3632EDD LTC3632EDD. For a proper measurement equipment configuration, set up the circuit according to the diagram in Figure 2. NOTE: When measuring the input or output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the input or output voltage ripple by touching the probe tip directly across the VIN or VOUT and GND terminals. See the Measurement Equipment Set-up diagram in Figure 1 for proper scope probe technique. To reduce the output voltage ripple further additional capacitor of 100µF can be added in parallel. Please follow the procedure outlined below for proper operation. and GND terminals. Refer to Figure 2 for the proper measurement equipment setup. 2. Before proceeding to operation, insert jumper shunt XJP1 into the OFF position and insert jumper shunt into JP2 for voltages of 1.8V, 3.3V or 5V respectively. Set the load output current to 20mA. 3. Apply 6V at VIN. Measure VOUT; it should read 0V. If desired, one can measure the shutdown supply current at this point. The supply current will be about 5 µA in shutdown. Set the load output current back to 0mA. 4. Turn on VOUT by changing shunt XJP1 from the OFF position to the ON position. The output voltage should measure according to the voltage set by the shunt jumper in JP2. 1. Connect the input power supply to the VIN and GND terminals. Connect the load between the VOUT 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1507A HIGH EFFICIENCY 20MA MONOLITHIC SYNCHRONOUS BUCK REGULATOR 5. Set the load output current to 1mA. Vary the input voltage from 6V to 50V and VOUT should be within a tolerance of ± 2.7%. 6. Set the input voltage to 10V. Vary the VOUT load current from 1mA to 20mA, and the output voltage should be within a tolerance of ± 2.7%. Warning - If the power for the demo board is carried in long leads, the input voltage at the part could "ring", which could affect the operation of the circuit or even exceed the maximum voltage rating of the IC. To eliminate the ringing, insert an electrolytic capacitor (for instance, Panasonic part # EEU-FC2A680L EEU-FC2A680L, 68µF/100V F/100V) on the pads between the input power and return terminals on the bottom of the demo board. The (greater) ESR of the electrolytic will dampen the (possible) ringing voltage due to the use of long input leads. On a normal, typical PCB, with short traces, the capacitor is not needed. Figure 1. Measuring Input or Output Ripple Figure 2. Proper Equipment Measurement setup 2 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1507A HIGH EFFICIENCY 20MA MONOLITHIC SYNCHRONOUS BUCK REGULATOR 3