DEMO MANUAL DC1516A LTC3833EFE Wide Input Range, High Efficiency Step-Down DC/DC Converter DESCRIPTION Demonstration circuit 1516A is a 1.5V/15A synchronous Other features of the board include a MODE jumper to buck converter operating with a switching frequency of program either DCM or CCM with light or no load, a PLLIN 300kHz over an input voltage range of 4.5V to 24V. The input for synchronizing the converter to an external clock, demo board comes in two versions. The -A version uses a TRACK/SS pin, a PGOOD pin and an EXTV pin. CC inductor DCR current sensing with an iron powder inductor The demo board uses a high density, two-sided drop-in for highest efficiency. The -B version uses a 2.5m/1% layout. The entire converter, excluding the bulk output and sense resistor for accurate current sensing with a low input capacitors, fits within a compact 1.25 0.5 area DCR ferrite inductor. The fixed on-time valley current on the board. The package style for the LTC3833EFE is a mode control of the LTC 3833 allows for a fast load step 20-lead TSSOP with an exposed ground pad. response (see Figures 4 and 5). The load step response Design files for this circuit board are available at can be tested with the on-board load step circuit and a DEMO MANUAL DC1516A QUICK START PROCEDURE Demonstration circuit 1516A is easy to set up to evalu- 2. Adjust the input voltage to be between 4.5V to 24V. ate the performance of the LTC3833EFE. Please refer to V should 1.5V 2%. OUT Figure1 for proper measurement equipment setup and 3. Next, apply 15A load and re-check V . OUT follow the procedure below. 4. Once the DC regulation is confirmed, observe the output 1. With power off, connect the input supply, load and voltage ripple, load step response, efficiency and other meters as shown in Figure 1. Preset the load to 0A parameters. and V supply to be 0V. Place jumpers in the following IN Note 1. To measure the output voltage ripple, use the BNC positions: connector labeled VOUT. JP1 RUN ON + Note 2. Do not apply the load from the VO SNS turret to JP2 MODE CCM the VO SNS turret. This will damage the converter. These turrets are only intended to monitor V across COUT3 OUT which is the point of regulation. LOAD STEP TRANSIENT TESTING (OPTIONAL) Demonstration circuit 1516A has a simple load step circuit 3. Connect the output of the pulse generator to the PULSE consisting of a MOSFET and sense resistor. To apply a load GEN turret and connect the return to the GND turret. step, follow the steps below. 4. With the converter running, slowly increase the ampli- 1. Pre-set the amplitude of a pulse generator to 0.0V and tude of the pulse generator output to provide the desired the duty cycle to 5% or less. load step pulse height. The scaling for the LOAD STEP signal is 10mV/Amp. 2. Connect the VOUT and LOAD STEP BNC connectors to the oscilloscope. Figure 1. Proper Measurement Equipment Setup dc1516af 2