PL560-37 Datasheet, PDF (12/15 Pages) Micrel Semiconductor – Analog Frequency Multiplier

Analog Frequency Multiplier
PL56X-XX VCXO Family
BOARD DESIGN AND LAYOUT CONSIDERATIONS
L2X and L4X: Try to reduce the PCB trace
inductance to a minimum by placing L2X and L4X as
physically close to their respective pins as possible.
Also be sure to bypass each Vdd connection
especially taking care to place a 0.01 uF bypass at
the Vdd side of L2X and L4X (see recommended
layout).
Crystal connections: Be sure to keep the ground
plane under the crystal connections continuous so
that the stray capacitance is consistent on both
crystal connections. Also be sure to keep the crystal
connections symmetrical with respect to one another
and the crystal connection pins of the IC. If you
chose to use a series capacitance and or inductor to
fine tune the crystal frequency be sure to put
symmetrical pads for this cap on both crystal pins
(see Cadj in recommended layout), even if one of
the capacitors will be a 0.01 uF and the other is
used to tune the frequency. To further maintain a
symmetrical balance on a crystal that may have
more internal Cstray on one pin or the other, place
capacitor pads (Cbal) on each crystal lead to ground
(see recommended layout). R3rd is only required if
a 3^rd overtone crystal is used.
V_DD and GND: Bypass VDDANA and VDDBUF with
separate bypass capacitors and if a V_DD plane is
used, feed each bypass cap with its own via. Be
sure to connect any ground pin including the bypass
caps with short via connections to the ground plane.
OESEL: J1 is recommended so the same PCB
layout can be used for both OESEL settings.
2X Layout (TSSOP)
4X Layout (TSSOP)
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax [phone] • www.micrel.com Rev 11/04/11 Page 12