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March 25, 2011 Document No. 001-16765 Rev. *B 1
AN1110 - Layout Recommendations for the
CY22050 and CY22150 Devices
Application Note Abstract
AN1110 provides a set of board layout recommendations for the CY22050 and CY22150. It includes schematics followed by
actual board layout diagrams. Also general rules for placement and resistor and capacitor values will be covered.
CY22050/CY22150
The CY22050 and CY22150 have one main difference, serial
programmability. The CY22150 has two serial programming
pins 4 and 10 which are SDAT and SCLK respectively. The
CY22050 replaces these pins with OE and PWRDWN.
Layout recommendations for both of these devices are very
similar except for the SDAT and SCLK pins. The CY22050
OE and PWRDWN pins have a built in 100 k pull-up, if
these features are not needed these pins can be left floating.
Series termination resistors are used to match the
impedance on your transmission lines to mitigate effects from
reflections. They should be placed as close to the output pins
as possible. The value of the resistor should be the trace
impedance minus the output impedance.
For example:
You have a 50 trace, a clock running at 3.3 V has an output
impedance of around 18 , so you get 50 – 18 = 32 .
Series resistor = 32
Decoupling capacitors should be placed as close to the
power pins as possible. A 0.1-F or 0.01-F capacitor should
be adequate decoupling for most systems. Additional
decoupling capacitors may be added in parallel.
Bulk bypass capacitors are used to prevent power supply
droop. They should be a low ESR tantalum cap with a value
between 10 F and 100
AN1110
Associated Project: No
Associated Part Family: CY22050/CY22150
Associated Application Notes: None
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