This test board features the LMZ31710 device configured for parallel operation. The test board operates over the entire input voltage range of the LMZ31710 device (2.95 to 17 V) with the option to select a split input power rail. The output voltage can be set to one of four popular values by using a configuration jumper (P4). This board can be configured to accept an external clock to set the switching frequency. Using a jumper, each paralleled LMZ31710 device can be configured to operate in phase with the controller or 180° out-of-phase. Input and output capacitors are included on the board to accommodate the entire range of input and output voltages. Current monitoring test points are available to measure the current of each device. Monitoring test points are provided to allow measurement of the following:

• Efficiency
• Power dissipation
• Input ripple
• Output ripple
• Line and load regulation
• Transient response

Control test points are provided to use the PWRGD, inhibit/UVLO, synchronization (CLK_IN), and slow-start or tracking features.

Figure 2-1 and Figure 2-2 highlight the user interface items associated with both the 2× and 4× LMZ31710 parallel test board. The polarized PVIN power terminal blocks are used to connect to the host input supply, and the polarized VOUT power terminal blocks are used to connect to the load. These terminal blocks can accept up to 16 AWG wire. The polarized VBIAS terminal block is used along with the VIN SELECT jumper (P1) when optional split power supply operation is desired. Refer to the LMZ31710 10-A Module, 2.95-V to 17-V Input and Current Sharing in QFN Package data sheet for further information on split power supply operation. Refer to Table 2-1 for terminal block numbering for either the 2× or 4× LMZ31710 parallel test board.

The PVIN monitor and VOUT monitor test points located near the power terminal blocks are intended as voltage monitoring points where digital voltmeters can connect to measure PVIN and VOUT.

The PVIN Scope and VOUT Scope test points can be used to monitor PVIN 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 barrel. The two sockets of each test point are on 0.1-inch centers. The scope probe tip should be connected to the socket labeled PVIN, or VOUT, and the scope ground lead should be connected to the socket labeled PGND.

The current monitor test points located above each LMZ31710 device are intended to be used with digital voltmeters to monitor the current across a 1-mΩ sense resistor located on the bottom of the board. The controls test points located on the perimeter of the board are made available to test the features of the device. Any external connections made to these test points should be referenced to an AGND test point. Refer to Section 3 for more information on the individual control test points.

The VOUT SELECT jumper (P4) is provided for selecting the desired output voltage. Before applying power to the test board, ensure that the jumper is present and properly positioned for the intended output voltage. Always remove input power before changing the jumper settings.

Wire-loop test points and scope probe test points have been provided as convenient connection points for digital voltmeters (DVM) or oscilloscope probes to aid in the evaluation of the test board. Table 3-1 provides a description of each test point.