W170-01G Datasheet, PDF (2/6 Pages) Cypress Semiconductor – Spread Aware, Frequency Multiplier and Zero Delay Buffer

W170-01
Pin Definitions
Pin Name
IN
FBIN
Pin No.
2
1
OUT1
6
OUT2
8
VDD
7
GND
3
FS0:1
4, 5
Pin
Type
I
I
O
O
P
P
I
Pin Description
Reference Input: The output signals will be synchronized to this signal.
Feedback Input: This input must be fed by one of the outputs (OUT1 or OUT2) to
ensure proper functionality. If the trace between FBIN and the output pin being used
for feedback is equal in length to the traces between the outputs and the signal desti-
nations, then the signals received at the destinations will be synchronized to the REF
signal input (IN).
Output 1: The frequency of the signal provided by this pin is determined by the feed-
back signal connected to FBIN, and the FS0:1 inputs (see Table 1).
Output 2: The frequency of the signal provided by this pin is one-half of the frequency
of OUT1. See Table 1.
Power Connections: Connect to 3.3V or 5V. This pin should be bypassed with a
0.1-µF decoupling capacitor. Use ferrite beads to help reduce noise for optimal jitter
performance.
Ground Connection: Connect all grounds to the common system ground plane.
Function Select Inputs: Tie to VDD (HIGH, 1) or GND (LOW, 0) as desired per
Table 1.
Overview
Spread Aware
The W170-01 is a two-output zero delay buffer and frequency
multiplier. It provides an external feedback path allowing max-
imum flexibility when implementing the Zero Delay feature.
This is explained further in the sections of this data sheet titled
“How to Implement Zero Delay,” and “Inserting Other Devices
in Feedback Path.”
The W170-01 is a pin-compatible upgrade of the Cypress
W42C70-01. The W170-01 addresses some application de-
pendent problems experienced by users of the older device.
Most importantly, it addresses the tracking skew problem in-
duced by a reference which has Spread Spectrum Timing en-
abled on it.
Many systems being designed now utilize a technology called
Spread Spectrum Frequency Timing Generation. Cypress has
been one of the pioneers of SSFTG development, and we de-
signed this product so as not to filter off the Spread Spectrum
feature of the Reference input, assuming it exists. When a zero
delay buffer is not designed to pass the SS feature through,
the result is a significant amount of tracking skew which may
cause problems in systems requiring synchronization.
For more details on Spread Spectrum timing technology,
please see the Cypress application note titled, “EMI Suppres-
sion Techniques with Spread Spectrum Frequency Timing
Generator (SSFTG) ICs.”
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