HFBR-0566 Avago Technologies US Inc., HFBR-0566 Datasheet - Page 2

• Manufacturer Part Number: HFBR-0566
• Description: Fiber Optic Development Tools MT-RJ 622Mb/s Fast E Evaluation Kit
• Manufacturer: Avago Technologies US Inc.

Specifications of HFBR-0566

• Description/function: Fiber Optic Kit
• For Use With/related Products: HFBR-5908E, HFCT-5908E
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

2
Functional Description
Receiver Section
Design
The receiver section of the HFBR/HFCT-5908E 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 separate circuit
board.
The postamplifier is ac coupled to the preamplifier as
illustrated in Figure 1. The coupling capacitors are large
enough to pass the SONET/SDH test pattern at 622 MBd
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 network which limits the
bandwidth of the preamp output signal. The filter is
designed to bandlimit the preamp output noise and thus
improve the receiver sensitivity.
These components will also reduce the sensitivity of the
receiver as the signal bit rate is increased above 622 MBd.
Figure 1. Receiver Block Diagram
TRANS-
IMPEDANCE
PRE-
AMPLIFIER
GND
FILTER
AMPLIFIER
SIGNAL DETECT
CIRCUIT
Noise Immunity
The receiver includes internal circuit components to filter
power supply noise. Under some conditions of EMI and
power supply noise, external power supply filtering may
be necessary. A power supply filter circuit is shown in the
Application Section.
The Signal Detect Circuit
The signal detect circuit works by sensing the peak level
of the received signal and comparing this level to a
reference.
PECL
OUTPUT
BUFFER
TTL
OUTPUT
BUFFER
DATA OUT
DATA OUT
SD