HFCT-5914ATLZ Avago Technologies US Inc., HFCT-5914ATLZ Datasheet - Page 2

• Manufacturer Part Number: HFCT-5914ATLZ
• Description: TXRX SMF LC 1.25GBD 2X10 EXT TMP
• Manufacturer: Avago Technologies US Inc.

Specifications of HFCT-5914ATLZ

• Data Rate: 1.25Gbps
• Wavelength: 1310nm
• Applications: Ethernet
• Voltage - Supply: 3.1 V ~ 3.5 V
• Connector Type: LC Duplex
• Mounting Type: Through Hole
• Supply Voltage: 3.3V
• Leaded Process Compatible: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Functional Description
Receiver Section
Design
The receiver section for the HFCT-5914ATLZ contains an
InGaAs/InP photo detector and a pre-amplifier mounted
in an optical subassembly. This optical subassembly is
coupled to a post-amplifier/decision circuit on a circuit
board. The design of the optical assembly is such that it
provides better than 12 dB Optical Return Loss (ORL).
The post-amplifier is ac coupled to the pre-ampli-
fier as illustrated in Figure 1. The coupling capacitors
are capable of passing the Gigabit Ethernet test pat-
tern at 1.25 Gb/s without any 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 pre-amplifier output signal. The filter
is designed to bandlimit the pre-amplifier 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 1.25 Gb/s.
The device incorporates a photodetector bias circuit.
This output must be connected to V
tored by connecting through a series resistor (see Ap-
plication Section).
Figure 1. Receiver Block Diagram
2
PHOTODETECTOR
BIAS
TRANS-
IMPEDANCE
PRE-
AMPLIFIER
GND
CC
FILTER
and can be moni-
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 peak level
of the received signal and comparing this level to a ref-
erence. The SD output is low voltage TTL.
PECL
OUTPUT
BUFFER
TTL
OUTPUT
BUFFER
DATA OUT
DATA OUT
SD