HFCT-5961TG Avago Technologies US Inc., HFCT-5961TG Datasheet - Page 2
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HFCT-5961TG
Manufacturer Part Number
HFCT-5961TG
Description
Manufacturer
Avago Technologies US Inc.
Datasheet
1.HFCT-5961TG.pdf
(16 pages)
Specifications of HFCT-5961TG
Optical Fiber Type
TX/RX
Data Transfer Rate
155Mbps
Optical Rise Time
2ns
Optical Fall Time
2ns
Operating Temperature Classification
Commercial
Peak Wavelength
1360nm
Package Type
DIP With Connector
Operating Supply Voltage (min)
3.1V
Operating Supply Voltage (typ)
3.3V
Operating Supply Voltage (max)
3.5V
Output Current
50mA
Operating Temp Range
0C to 70C
Mounting
Snap Fit To Panel
Pin Count
10
Lead Free Status / RoHS Status
Compliant
Functional Description
Receiver Section
Design
The receiver section for the HFCT-5961TL/TG/NL/NG/
ATL/ATG contains an InGaAs/InP photo detector and a
preamplifier mounted in an optical subassembly. This
optical subassembly is coupled to a postamp/decision
circuit on a circuit board. The design of the optical as-
sembly is such that it provides better than 14 dB Optical
Return Loss (ORL).
The postamplifier is ac coupled to the preamplifier as il-
lustrated in Figure 1. The coupling capacitors are large
enough to pass the SONET/SDH test pattern at 155 Mb/
s without significant distortion or performance penalty.
If a lower signal rate, or a code which has significantly
more low frequency content is used, sensitivity, jitter
and pulse distortion could be degraded.
Figure 1 also shows a filter function which limits the
bandwidth of the preamp output signal. The filter is de-
signed to bandlimit the preamp output noise and thus
improve the receiver sensitivity.
These components will reduce the sensitivity of the re-
ceiver as the signal bit rate is increased above 155 Mb/s.
2
Figure 1. Receiver Block Diagram
PHOTODETECTOR
BIAS
TRANS-
IMPEDANCE
PRE-
AMPLIFIER
GND
FILTER
AMPLIFIER
CIRCUIT
SIGNAL
DETECT
Noise Immunity
The receiver includes internal circuit components to
filter power supply noise. However under some condi-
tions of EMI and power supply noise, external power
supply filtering may be necessary (see Application Sec-
tion).
The Signal Detect Circuit
The signal detect circuit works by sensing the level of
the received signal and comparing this level to a refer-
ence. The SD output is low voltage PECL.
LVPECL
OUTPUT
BUFFER
LVPECL
OUTPUT
BUFFER
DATA OUT
DATA OUT
SD