Symbol

Pin

IO

Description

No

VCO RST

11

I

VCO Reset

TTL compatible input used to reset the internal VCO on system power up This input

stops the VCO from oscillating when at a logic HI level thereby reinitializing each of the gates in

the ring oscillator

3

O

Transmit Clock

100K ECL compatible differential outputs for use at 125 MHz as the fiber

medium Transmit Clock (TXC) source for the PLAYER device

2

27

O

Transmit Byte Clock

100K ECL compatible differential outputs for use at 125 MHz as a load

strobe or transmit byte clock by the PLAYER device to convert byte wide data to serial format for

26

fiber medium transmission These outputs are positioned to transition on the falling edge of the

coherent with the TTL LBC1 output but the phase transition occurs approximately 10 ns earlier

LBC1 thru 5

25 24

O

Local Byte Clocks

TTL compatible local byte clock outputs which are phase locked to crystal

oscillator reference signals These outputs have a 50% duty cycle waveform at 125 MHz The

23 22 21

PHASE SEL input determines whether the five phase outputs are phase offset by 8 ns or 16 ns

LSC

20

O

Local Symbol Clock

TTL compatible 25 MHz output for driving the BMAC device This output’s

negative phase transition is aligned with the LBC1 output transitions and has a 40% HI and 60%

LOW duty cycle

PHASE SEL

19

I

Phase Select

TTL compatible input used to select eithera8nsor16ns phase offset between

the 5 local byte clocks The LBC’s are phase offset 8 ns apart when PHASE SEL is at a logic LOW

level and 16 ns apart when at a logic HI level

6