AFCT-57J7ATPZ Avago Technologies US Inc., AFCT-57J7ATPZ Datasheet - Page 3

• Manufacturer Part Number: AFCT-57J7ATPZ
• Description: TXRX OPT SFP OBSAI/CPRI DMI
• Manufacturer: Avago Technologies US Inc.

Specifications of AFCT-57J7ATPZ

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Figure 1. Transceiver functional diagram.
Transmitter Section
The transmitter section includes a 1310-nm distributed
feedback (DFB) laser and a transmitter driver circuit. The
driver circuit maintains a constant average optical power
output with Fibre Channel and Ethernet 8B/10B coded
data. Optical connection to the transmitter is provided via
an LC connector. The TOSA is driven by a custom IC which
uses the incoming diff erential 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 AFCT-57J7ATPZ accepts a TTL and CMOS compatible
transmit disable control signal input (pin 3) which shuts
down the transmitter optical output. A high signal imple-
ments this function while a low signal allows normal trans-
ceiver 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).
3
OPTICAL INTERFACE
LIGHT FROM FIBER
LIGHT TO FIBER
RECEIVER
TRANSMITTER
PHOTO-DETECTOR
DFB Laser
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 AFCT-57J7ATPZ 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 certifi cation.
Such unsafe conditions can be due to inputs from the host
board (Vcc fl uctuation, unbalanced code) or a fault within
the transceiver.
CIRCUITRY
DRIVER &
SAFETY
LASER
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
ELECTRICAL INTERFACE