The EVDD408/EVDD409/EVDI409/EVDN409/EVDD414 evaluation boards are general-purpose circuit boards designed to simplify the evaluation of the IXYS IXDD408, IXDD409, IXDI409, IXDN409 and IXDD414 gate drive ICs, as well as to provide a building block for power circuit development. Any of the four gate driver package types (SO8, Dip 8, 5pin TO-220 and the 5pin TO-263) may be installed in the driver (the 5-Pin TO-263 is factory installed). The board enables the user to drive MOSFETs or IGBTs in the TO-220, TO-247, TO-264 or SOT-227 packages. The evaluation board design allows these MOSFETS to be attached to a heat sink, and in so doing the board assembly can be used as a ground referenced, low side power switch for both single-ended and push-pull configurations. The board layout for the gate driver in the TO-220 and the TO-263 packages (designator U1B), allows the ground tab to be soldered to the ground plane for cooling in high-power, high frequency applications with large MOSFET devices. Circuitry for the TriState function is also included on the evaluation board. Figure 1 is a photograph of the Evaluation Board loaded with an IXDD408YI TO-263 driver and a SOT-227 MOSFET. The low level inputs are shown on the left side of the board. Control is a TTL high true input which controls the on or off state of the power switch Q1, Q2, or Q3. Enable is a low true input, which controls the Tri-State output (IXDD408, IXDD409 and IXDD414 devices only). VCC-IN is the low voltage, (825V) power input, (see Figure 3 below). Figure 2 illustrates the MOSFET mounting of a TO-220, TO-247, or TO-264 device. The MOSFET is mounted on the back side of the PCB. A large through hole is provided so that the device can be attached to a heat sink. The SOT-227 (shown in the photograph) is mounted in a similar manner. Circuit Operation