105
Notes:
1. This is the maximum voltage that can 
be applied across the Differential 
Transmitter Data Inputs to prevent 
damage to the input ESD protection 
circuit.
2. The outputs are terminated with 50 Ω 
connected to VCC-2V.
3. The specified signaling rate of 
10 MBd to 125 MBd guarantees 
operation of the transmitter and 
receiver link to the full conditions 
listed in the FDDI Physical Layer 
Medium Dependent standard. 
Specifically, the link bit error ratio 
will be equal to or better than
2.5 x 10
-10
 for any valid FDDI 
pattern. The transmitter section of 
the link is capable of dc to 125 MBd. 
The receiver is internally ac-coupled 
which limits the lower signaling rate 
to 10 MBd. For purposes of 
definition, the symbol rate (Baud), 
also called signaling rate, fs, is the 
reciprocal of the shortest symbol 
time. Data rate (bits/sec) is the 
symbol rate divided by the encoding 
factor used to encode the data 
(symbols/bit).
4. The power supply current needed to 
operate the transmitter is provided to 
differential ECL circuitry. This 
circuitry maintains a nearly constant 
current flow from the power supply. 
Constant current operation helps to 
prevent unwanted electrical noise 
from being generated and conducted 
or emitted to neighboring circuitry.
5. This value is measured with an output 
load RL = 10 kΩ.
6. This value is measured with the outputs terminated into 50 Ω connected 
to VCC- 2 V and an Input Optical 
Power level of -14 dBm average.
7. The power dissipation value is the 
power dissipated in the receiver 
itself. Power dissipation is calculated 
as the sum of the products of supply 
voltage and currents, minus the sum 
of the products of the output voltages 
and currents.
8. This value is measured with respect to 
VCC with the output terminated into 
50 Ω connected to VCC-2V.
9. The output rise and fall times are 
measured between 20% and 80% 
levels with the output connected to 
VCC- 2 V through 50 Ω.
10. Duty Cycle Distortion contributed by 
the receiver is measured at the 50% 
threshold using an IDLE Line State, 
125 MBd (62.5 MHz square-wave),
input signal. The input optical power 
level is -20 dBm average. See 
Application Information - Transmitter 
Jitter Section for further information.
11. Data Dependent Jitter contributed by 
the receiver is specified with the 
FDDI DDJ test pattern described in 
the FDDI PMD Annex A.5. The input 
optical power level is -20 dBm 
average. See Application Information
- Transmitter Jitter Section for 
further information.
12. Random Jitter contributed by the 
receiver is specified with an IDLE 
Line State, 125 Mbd (62.5 MHz 
square-wave), input signal. The input 
optical power level is at maximum 
“P
IN Min.
 (W).” See Application 
Information - Transmitter Jitter 
Section for further information.
13. These optical power values are 
measured with the following 
conditions:
• The Beginning of Life (BOL) to the 
End of Life (EOL) optical power 
degradation is typically 1.5 dB per 
the industry convention for long 
wavelength LEDs. The actual 
degradation observed in HewlettPackard’s 1300 nm LED products 
is < 1 dB, as specified in this data 
sheet.
• Over the specified operation voltage 
and temperature ranges.
• With HALT Line State, (12.5 MHz 
square-wave), input signal.
• At the end of one meter of noted 
optical fiber with cladding modes 
removed.
The average power value can be 
converted to a peak power value by 
adding 3 dB. Higher output optical 
power transmitters are available on 
special request.
14. The Extinction Ratio is a measure of 
the modulation depth of the optical 
signal. The data “0” output optical 
power is compared to the data “1” 
peak output optical power and 
expressed as a percentage. With the 
transmitter driven by a HALT Line 
State (12.5 MHz square-wave) signal, 
the average optical power is 
measured. The data “1” peak power is 
then calculated by adding 3 dB to the 
measured average optical power. The 
data “0” output optical power is 
found by measuring the optical power 
when the transmitter is driven by a 
logic “0” input. The extinction ratio is 
the ratio of the optical power at the 
“0” level compared to the optical
power at the “1” level expressed as a 
percentage or in decibels.
15. The transmitter provides compliance 
with the need for Transmit_Disable 
commands from the FDDI SMT layer 
by providing an Output Optical 
Power level of < -45 dBm average in 
response to a logic “0” input. This 
specification applies to either
62.5/125 µm or 50/125 µm fiber 
cables.
16. This parameter complies with the 
FDDI PMD requirements for the 
tradeoffs between center wavelength, 
spectral width, and rise/fall times 
shown in Figure 9.
17. This parameter complies with the 
optical pulse envelope from the FDDI 
PMD shown in Figure 10. The optical 
rise and fall times are measured from 
10% to 90% when the transmitter is 
driven by the FDDI HALT Line State 
(12.5 MHz square-wave) input signal.
18. Duty Cycle Distortion contributed by 
the transmitter is measured at a 50% 
threshold using an IDLE Line State, 
125 MBd (62.5 MHz square-wave), 
input signal. See Application Information – Transceiver Jitter Performance 
Section of this data sheet for further 
details.
19. Data Dependent Jitter contributed by 
the transmitter is specified with the 
FDDI test pattern described in FDDI 
PMD Annex A.5. See Application 
Information – Transceiver Jitter 
Performance Section of this data 
sheet for further details.
20. Random Jitter contributed by the 
transmitter is specified with an IDLE 
Line State, 1256 MBd (62.5 MHz 
square-wave), input signal. See 
Application Information – Transceiver Jitter Performance Section of 
this data sheet for further details.
21. This specification is intended to indicate the performance of the receiver 
section of the transceiver when Input 
Optical Power signal characteristics 
are present per the following 
definitions. The Input Optical Power 
dynamic range from the minimum 
level (with a window time-width) to 
the maximum level is the range over 
which the receiver is guaranteed to 
provide output data with a Bit Error 
Ratio (BER) better than or equal to
2.5 x 10
-10
.
• At the Beginning of Life (BOL).
• Over the specified operation
temperature and voltage ranges.