|NB3N501DG||3.3V / 5.0V 13 MHz to 160 MHz PLL Clock Multiplier|
|NB3N501DG Datasheet PDF : 6 Pages |
High Frequency CMOS/TTL Oscillators
The NB3N501, along with a low frequency fundamental
mode crystal, can build a high frequency TTL output
oscillator. For example, a 20 MHz crystal connected to the
NB3N501 with the 5X output selected (S1 = L, S0 = H)
produces an 100 MHz CMOS/TTL output clock.
Decoupling and External Components
The NB3N501 requires a 0.01 mF decoupling capacitor to
be connected between VDD and GND on pins 2 and 3. It must
be connected close to the NB3N501 to minimize lead
inductance. Control input pins can be connected to device
pins VDD or GND, or to the VDD and GND planes on the
Series Termination Resistor
A 33 W terminating resistor can be used next to the CLK
pin for trace lengths over one inch.
Crystal Load Capacitors
The total on chip capacitance is approximately 12 pF. A
parallel resonant, fundamental mode crystal should be used.
The device crystal connections should include pads for
small capacitors from X1 to ground and from X2 to ground.
These capacitors are used to adjust the stray capacitance of
the board to match the nominally required crystal load
capacitance. Because load capacitance can only be
increased in this trimming process, it is important to keep
stray capacitance to a minimum by using very short PCB
traces (and no vias) between the crystal and device. Crystal
capacitors, if needed, must be connected from each of the
pins X1 and X2 to ground. The value (in pF) of these crystal
caps should equal (CL − 12 pF) * 2. In this equation, CL =
crystal load capacitance in pF. Example: For a crystal with
a 16 pF load capacitance, each crystal capacitor would be
8 pF [(16 − 12) x 2 = 8].
98 Units / Rail
2500 / Tape & Reel
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specification Brochure, BRD8011/D.
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