NB3N502DEVB NB3N502 Evaluation Board Users Manual NB3N502DEVB SETUP FOR MEASUREMENTS Basic Equipment mode crystal should be used. The evaluation board includes pads for small capacitors from X1/CLK to ground and from Signal Generator (for External Reference Clock Input) X2 to ground. These capacitors, CL1 and CL2, are used to Oscilloscope adjust the stray capacitance of the board to match the Power Supply nominally required crystal load capacitance (CLOAD Voltmeter (crystal)). Crystal load capacitors must be connected from HighSpeed Cables with SMA Connectors each of the pins X1 and X2 to ground. The load capacitance HighImpedance Probe of the crystal (CLOAD (crystal)) must be matched by total load capacitance of the oscillator circuitry network, CINX, Power Supply Connections CSX and CLX, as seen by the crystal (see Figure 3 and External power supply of +3 V to +5.5 V must be equations below). provided to the board. CLOAD1 = CIN1 + CS1 + CL1 The NB4N502 has a positive supply pin, V , and a DD Total capacitance on X1/CLK ground pin, GND. Connect a single power supply to the CLOAD2 = CIN2 + CS2 + CL2 Total capacitance on X2 evaluation board (see Figure 2.) by connecting V to the DD positive supply, +3 V to +5.5 V, and GND to 0 V. Power CIN1 CIN2 12 pF (Typ) Internal capacitance supply banana plug connectors for V and GND are DD CS1 CS2 5 pF (Typ) External PCB stray capacitance provided at the top corners of the board. CLOAD1,2 = 2 CLOAD (Crystal) CL2 = CLOAD2 CIN2 CS2 Table 1. POWER SUPPLY CONNECTIONS External load capacitance on X2 Supply Value Connector CL1 = CLOAD1 CIN1 CS1 V +3 to +5.5 V Red Banana Plug DD External load capacitance on X1/CLK GND 0 V Black Banana Plug Internal R Power Supplies to Device G C C IN1 IN2 + 12pF 12pF GND X1/CLK X2 V DD C C S1 S2 C C L1 L2 +3.0 V to +5.5 V Figure 2. Power Supply Connections Crystal Figure 3. Using a Crystal as Reference Clock External Reference Clock An SMA connector is provided for X1/CLK if an external Control and Select Pins clock source is used on Pin 1. The metal trace at the package The NB4N502 evaluation board is equipped with SMA pin is intentionally open for crystal use and must be shorted connectors to control the static input logic levels of the for a connection to Pin 1 for external clock use. Multiplier Select pins, S0 and S1 (see Table 2). Crystal and Crystal Load Capacitors Selection Guide Pin S1 defaults to M when left open. Pin S0 defaults to H A throughhole or surface mount crystal can be used. The when left open. metal traces at the crystal pins are intentionally open for 3Position slide switches are also provided to control the crystal use and will have no impedance effect on the crystal Multiplier Select pins. To use the switches, headers JMP3 pins. and JMP4 must be shorted. The total onchip capacitance is approximately 12 pF per pin (CIN1 and CIN2). A parallel resonant, fundamental