HFCT-5911ATLZ Avago Technologies US Inc., HFCT-5911ATLZ Datasheet - Page 2

• Manufacturer Part Number: HFCT-5911ATLZ
• Description: TXRX SMF LC 1.25GBD 2X5 EXT TEMP
• Manufacturer: Avago Technologies US Inc.

Specifications of HFCT-5911ATLZ

• 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-5911ATLZ contains
an InGaAs/InP photo detector and a pre-amplifier
mounted in an optical subassembly. This optical subas-
sembly 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-amplifier as
illustrated in Figure 1. The coupling capacitors are capa-
ble of passing the Gigabit Ethernet test pattern at 1.25
Gb/s without any significant distortion or performance
penalty. If a lower signal rate, or a code which has sig-
nificantly more low frequency content is used, sensitiv-
ity, 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.
Figure 1. Receiver Block Diagram
2
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 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