QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 630 PIEZOCERAMIC MICROACTUATOR DRIVER WITH BOOST REGULATOR LT3469ETS8 DESCRIPTION Demonstration circuit 630 is a g amplifier circuit using the supply voltage of the amplifier combine to allow the wide m LT 3469ETS8 and can drive an output up to 34V at 25mA output voltage range needed to drive a piezoceramic from 5V or 12V supply. An internal Boost converter of the microactuator. LT3469 generates a supply voltage up to 36V for the g m Design files for this circuit board are available. Call the amplifier. This regulator switches at 1.5MHz, allowing the LTC factory. use of a tiny external inductor and capacitor. The 36V output LT is a trademark of Linear Technology Corporation capability of the switching regulator along with the high QUICK START PROCEDURE Demonstration circuit 630 is easy to set up to evaluate the and the input current Iin within the range of 34mA to performance of the LT3469ETS8. Refer to Figure 1 for proper 50mA. measurement equipment setup and follow the procedure 4. Apply V =16V, Vinput=1V, and Iout=0A (no load). Verify IN below: the boost regulator output Vcc=35.25%. NOTE: When measuring the input or output voltage ripple, 5. Apply V =5V, Vinput=0.1V, check the amplifier output care must be taken to avoid a long ground lead on the IN V = within the range of 0.87V to 1.12V. oscilloscope probe. Measure the input or output voltage OUT ripple by touching the probe tip directly across the V IN 6. Apply V =5V, Vinput=3V, check the amplifier output IN or V and GND terminals. See Figure 2 for proper OUT V = 33V2%, OUT scope probe technique. 7. Apply V =5V and pulsed square wave input that swings IN 1. With power off, connect the input power source V to the IN from 0.1V to 2.8V and has period of 300s to Vinput, and VIN and GND terminals, connect Vinput to INPUT+ and apply 27nF capacitor load to the output. Verify V and OUT GND terminals. Iout as shown in Figure 3. 2. Apply V =4.75V, Vinput=1V, and Iout=0mA (no load). IN Check the boost regulator output Vcc=34.8V5%, and input current Iin within the range of 21mA to 35mA. 3. Apply V =4.75V, Vinput=1V, and Iout=2mA (2mA load at IN V ). Check the boost regulator output Vcc=34.6V5%, OUT 1 GND VIN QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 630 PIEZOCERAMIC MICROACTUATOR DRIVER WITH BOOST REGULATOR I OUT V IN Figure 1. Proper Measurement Equipment Setup Figure 2. Measuring Input or Output Ripple 2