74AUP1Z04EVB Nexperia

NXPs AUP1Z04 Demo board Low-power crystal driver with enable and internal bias resistor The 74AUP1Z04 combines the functions of the 74AUP1GU04 and 74AUP1G04 with enable circuitry and an internal bias resistor to provide a device optimized for use in crystal oscillator applications. When not in use the EN input can be driven HIGH, pulling up the X1 input and putting the device in a low power disable mode. Schmitt trigger action at the EN input makes the circuit tolerant to slower input rise and fall times across the entire V range from 0.8 V to 3.6 V. CC This device is fully specified for partial power-down applications using I at OFF output Y. The I circuitry disables the output Y, preventing the damaging OFF backflow current through the device when it is powered down. The integration of the two devices into the 74AUP1Z04 produces the benefits of a compact footprint, lower power dissipation and stable operation over a wide range of frequency and temperature. Key Features and Benefits Low power crystal driver with integrated output enable function to save power The integrated bias resistor provides negative feedback and sets a bias point of inverter near mid-supply, eliminating the need of external resister Stable operation over wide range of supply voltage, frequency and temperature I circuitry provides partial power-down mode operation at output Y OFF Over supply voltage tolerant inputs up to 3.6V Demo board is available which can be optimized for different system loads and evaluate the part under different test conditions Very small footprint and availability in leadless MicroPak packages Key Features and Benefits Wide supply voltage range from 0.8 V to 3.6 V High noise immunity Low noise overshoot and undershoot < 10 % of V CC Specified from 40 C to +85 C and 40 C to +125 C Schematics of AUP1Z04 demo board are shown in figure below. A supply voltage of 0.8V to 3.6V can be used for the board. Values of C1 and C2 are calculated so that a parallel combination of C1 and C2 is equal to recommended load capacitance of crystal (C ), specified in the crystal data sheet. Crystal with different frequencies can L be used on the board with out changing C1 and C2, as long as the load capacitance and foot print are same. Reference board uses a 25MHz crystal (NX5032GA) from NDK with 8pF load capacitance. NX5032GA is also available in same foot print (5mm x 3.2mm) and 8pF load capacitance in frequency range of 8MHz to 25MHz. C1 x C2 C = L (C1 + C2) R1 isolates the output of the inverter from the crystal and prevents spurious high- frequency oscillation, so that a clean waveform can be obtained. The optimum value of R1 depends on the frequency of operation and the required stability. The minimum value of R1 depends on the recommended power consumption of the crystal. Crystal manufacturers usually specify a recommended value of R1 in the crystal data sheet. Using a R1 value lower than that in the crystal data sheet may cause overdriving of the crystal and result in damage to the crystal or shorten the crystal life. Demo board circuit schematics