This EVM features the TPSM84824/624/424 synchronous buck power module configured for operation with a 4.5-V to 17-V input voltage range. The output voltage can be set to one of six popular values by using a configuration jumper. Similarly, the switching frequency can be set to one of six values with a jumper. Additionally, the RTT resistor value, which selects the TurboTrans feature for improved transient response, is also selectable using a jumper. The full output current rating of the device can be supplied by the EVM. Input and output capacitors are included on the board to accommodate the entire range of input and output voltages. Monitoring test points are provided to allow measurement of efficiency, power dissipation, input ripple, output ripple, line and load regulation, and transient response. Control test points and component footprints are provided for use of the ENABLE, PGOOD, and CLK features of the device. The EVM uses a recommended PCB layout that maximizes thermal performance and minimizes output ripple and noise.

Figure 2-1 highlights the user interface items associated with the EVM. The VIN Power terminal block (J1) is used for connection to the host input supply and the VOUT Power terminal block (J2) is used for connection to the load. These terminal blocks can accept up to 16-AWG wire.

Figure 2-1 EVM User Interface

The S+ and S- test points for both VIN and VOUT, located near the power terminal blocks are intended to be used as voltage monitoring points where voltmeters can be connected to measure VIN and VOUT. Do not use these S+ and S- monitoring test points as the input supply or output load connection points. The PCB traces connecting to these test points are not designed to support high currents.

The VIN Scope (J3) and VOUT Scope (J4) test points can be used to monitor VIN and VOUT waveforms with an oscilloscope. These test points are intended for use with un-hooded scope probes outfitted with a low-inductance ground lead (ground spring) mounted to the scope probe barrel. The two sockets of each test point are on 0.1 inch centers. The scope probe tip should be inserted into the socket marked with a white dot, and the scope ground lead should be inserted into the other socket.

The control test points located to the left of the device are made available to test the features of the device. The UVLO feature can be adjusted by changing resistors R24 and R25 on the bottom of the board. An external voltage can be applied to the PULL_UP test point for the PGOOD signal. Refer to the Test Points Descriptions section of this guide for more information on the individual control test points.

The Fsw SELECT jumper (P1), the VOUT SELECT jumper (P2) and the RTT SELECT jumper (P3) are provided for selecting the desired output voltage, the appropriate switching frequency and the appropriate TurboTrans resistor value. Before applying power to the EVM, ensure that the jumpers are present and properly positioned for the intended output voltage, switching frequency, and TurboTrans resistor value. Refer to Table 2-1 for the recommended jumper settings. Always remove input power before changing the jumper settings.