AFBR-57R6APZ Avago Technologies US Inc., AFBR-57R6APZ Datasheet - Page 3

• Manufacturer Part Number: AFBR-57R6APZ
• Description: MM 4/2/1 Gb RoHS W Rate Select
• Manufacturer: Avago Technologies US Inc.

Specifications of AFBR-57R6APZ

• Data Rate: 4.25Gbps
• Wavelength: 850nm
• Applications: Ethernet
• Voltage - Supply: 2.97 V ~ 3.63 V
• Connector Type: LC Duplex
• Mounting Type: SFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3
Transmitter Section
The transmitter section includes the Transmitter Optical
SubAssembly (TOSA) and laser driver circuitry. The
TOSA, containing an 850 nm VCSEL (Vertical Cavity
Surface Emitting Laser) light source, is located at the
optical interface and mates with the LC optical
connector. The TOSA is driven by a custom IC which
uses the incoming differential high speed logic signal to
modulate the laser diode driver current. This Tx laser
driver circuit regulates the optical power at a constant
level provided the incoming data pattern is dc balanced
(8B/10B code, for example).
Transmit Disable (Tx_Disable)
The AFBR-57R6APZ accepts a TTL and CMOS
compatible transmit disable control signal input
(pin 3) which shuts down the transmitter optical output.
A high signal implements this function while a low
signal allows normal transceiver operation. In the
event of a fault (e.g. eye safety circuit activated), cycling
this control signal resets the module as depicted in
Figure 4. An internal pull up resistor disables the
transceiver transmitter until the host pulls the input
low. Host systems should allow a 10 ms interval between
successive assertions of this control signal. Tx_Disable
can also be asserted via the two-wire serial interface
(address A2h, byte 110, bit 6) and monitored (address
A2h, byte 110, bit 7).
Figure 1. Transceiver functional diagram.
OPTICAL INTERFACE
LIGHT FROM FIBER
LIGHT TO FIBER
RECEIVER
TRANSMITTER
PHOTO-DETECTOR
VCSEL
CONTROLLER & MEMORY
AMPLIFICATION
& QUANTIZATION
The contents of A2h, byte 110, bit 6 are logic OR’d
with hardware Tx_Disable (pin 3) to control
transmitter operation.
Transmit Fault (Tx_Fault)
A catastrophic laser fault will activate the transmitter
signal, TX_FAULT, and disable the laser. This signal
is an open collector output (pull-up required on the
host board). A low signal indicates normal laser
operation and a high signal indicates a fault. The
TX_FAULT will be latched high when a laser fault
occurs and is cleared by toggling the TX_DISABLE
input or power cycling the transceiver. The transmitter
fault condition can also be monitored via the two-wire
serial interface (address A2, byte 110, bit 2).
Eye Safety Circuit
The AFBR-57R6APZ provides Class 1 (single fault
tolerant) eye safety by design and has been tested for
compliance with the requirements listed in Table 1.
The eye safety circuit continuously monitors the
optical output power level and will disable the
transmitter upon detecting an unsafe condition
beyond the scope of Class 1 certification. Such unsafe
conditions can be due to inputs from the host board
(Vcc fluctuation, unbalanced code) or a fault within
the transceiver.
CIRCUITRY
DRIVER &
SAFETY
LASER
ELECTRICAL INTERFACE
RATE SELECT
RD+ (RECEIVE DATA)
RD– (RECEIVE DATA)
Rx LOSS OF SIGNAL
MOD-DEF2 (SDA)
MOD-DEF1 (SCL)
MOD-DEF0
TX_DISABLE
TD+ (TRANSMIT DATA)
TD– (TRANSMIT DATA)
TX_FAULT