DC1589A Analog Devices

QUICK START GUIDE FOR DC1589A LTC4425EDD: Linear Supercap Charger With Current-Limited Ideal Diode And V/I Monitor DESCRIPTION Demonstration Circuit DC1589A is a Linear Supercap Charger with Current-Limited Ideal Diode and V/I Monitor, featuring the LTC 4425. PERFORMANCE SUMMARY Specifications are at T = 25C A SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Vin Input Voltage Range 2.7 5.5 V Icharge Supercap Charge current 2 A VOUT Supercap Stack Output Voltage 1.2 5.4 V V(MID) Supercap Midpoint Voltage 0.6 2.7 V QUICK START PROCEDURE Refer to Figure 1 for the proper measurement equipment setup and jumper settings and follow the procedure below. 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 VBUS or VOUT(x) and GND terminals. See Figure 2 for proper scope probe technique. 1. Set b 2-0 jmpers (JP3, JP4, JP5) to 1. Set MODE (JP6) to LDO. Set LD1 to 0A, and PS1 to 5V. Observe VOUT (VM3) = 3.3V, I(VIN) (AM1) = 2A, and V(PROG) (VM2) = 1V. Note: The supercapacitor COUT1 will charge in ap- proximately 0.5 seconds, so please observe these signals within a few seconds of setting PS1 to 5V. 2. Set PS1 to 0V. Observe D1 (PFO) should be lit due to input power failure 3. Set LD1 to 1A. Observe VOUT. VOUT should decrease to 0V, in about 1 second. 1GND VIN LTC4425EDD - VM2 + AM1 + - + - + + LD1 AM2 VM3 0V - 5V + PS1 + - - 2A VM1 4.35V - 5.5V supply 1A - - Note: All connections from equipment should be Kelvin connected directly to the board pins which they are connected on this diagram and any input or output leads should be twisted pair. Figure 1. Proper Measurement Equipment Setup for DC1550A Figure 2. Measuring Input or Output Ripple 2