80KSBR200 Datasheet, PDF (113/172 Pages) Integrated Device Technology – sRIO SERIAL BUFFER FLOW-CONTROL DEVICE

IDT 80KSBR200
Notes
Advanced Datasheet*
10.0 Reference Clock
There are several clocks associated with the SerB. All internal operational clocks within the SerB are generated from
the PHY Reference clock operating at 156.25M Hz. The following clocks are used within the SerB:
1. PHY Reference Clock. This clock is an input at 156.25M Hz and is used to drive the serial ports and internal
functions. When P-Port is a QDR memory port, the PHY Reference clock also drives the memory interface.
2. JTAG Clock
3. I²C Clock
10.1 Reference Clock Electrical Specifications
The reference clock is 156.25 MHz, and is AC-coupled with the following electrical specifications:
REF_CLK_P
REF_CLK_N
LI, CLK
CI, CLK
RL,CLK
+
VBIAS, CLK
LI, CLK
-
RL,CLK
CI, CLK
5686 drw07
Figure 12 REF_CLK representative circuit
REF_CLK
Name
REF_CLK
tDUTY_REF
tRCLK/tFCLK
vIN_CML
RL_CLK
LI_CLK
CI_CLK
Description
Min Nom
REF_CLK clock running at 156.25Mhz
-100
----
REF_CLK duty cycle
40
50
Input signal rise/fall time (20%-80%)
Differential peak-peak REF_CLK input swing
200
500
400
----
Input termination resistance
Input inductance
40
50
-----
-----
Input capacitance
-----
-----
Table 96 Input Reference Clock Jitter Specifications
Max Units
+100
ppm
60
%
650
ps
2400
mV
60
ohm
4
nH
5
pF
The reference clock wander should not be more than 100ppm (for 156.25 Mhz, this is +/-15.625 KHz). This requirement
comes from the sRIO specification that outgoing signals from separate links, which belong to the same port, should not be
separated more than 100ppm.
Note that the series capacitors are descretes that must be placed external to the devices’s receivers. All other elements
are associated with the input structure internal to the device. V_BIAS is generated internally.
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March 19, 2007
„2005 Integrated Device Technology, Inc. All rights reserved. Advanced Datasheet for informational purposes only. Product specifications subject to change without notice.NOT AN OFFER FOR SALE The information presented herein is subject to a
Non-Disclosure Agreement (NDA) and is for planning purposes only. Nothing contained in this presentation, whether verbal or written, is intended as, or shall have the effect of, a sale or an offer for sale that creates a contractual power of acceptance.