Optical Transceiver SFP 2.5Gb/s 20KM 1490nm SC

Product Specification Sheet

OLSG4325S-CD20TB

RoHS Compliant GPON SFP OLT B+ Optical Transceiver

PRODUCT FEATURES

 Single Fiber Transceiver with single mode SC receptacle

 1310nm burst-mode 1.25G transmitter with DFB Laser

 1490nm continuous-mode 2.5G receiver with APD-TIA

 Meets ITU-T G.984.2 Class C+

 Digital diagnostic interface compliant with SFF-8472 Rev 9.4, Digital Diagnostic Monitoring (DDM) with external calibration

 3.3V Single power supply

 LVPECL interface logic level for data input

 CML interface logic level for data output

 Differential line input/output impedance 100 ohm

 LVTTL for burst signal input and signal detect output

 Complies with RoHS directive (2002/95/EC)

 Operating case temperature: Standard : 0 to +70°C

APPLICATIONS

 Gigabit Passive Optical Networks (G-PON) - ONU side

PRODUCT DESCRIPTIONS

The OLSG3412S-CD20UB transceiver is a high performance module for single fiber communications using a 1310nm burst-mode transmitter and a 1490nm continuous-mode receiver. It is used in the optical network terminal (ONT) for GPON ONT Class B+ applications.

The Transmitter is designed for single mode fiber and operates at a nominal wavelength of 1310nm. The transmitter module uses a DFB laser diode with full IEC825 and CDRH class 1 eye safety. It contains APC functions, a temperature compensation circuit to ensure compliance with G.984.2 requirement at operating temperature, LVPECL data inputs and DC coupling circuit.

The receiver section uses a hermetic packaged APD TIA (APD with trans-impedance amplifier) and a limiting amplifier. The APD converts optical power into electrical current and the current is transformed to voltage by the trans-impedance amplifier. The differential DATA and /DATA CML data signals are produced by the limiting amplifier. The APD TIA is AC coupled to the limiting amplifier through a low pass filter. As the optical input power decreases, the Signal Detect will switch from high to low (de-assert point). As the optical input power is increases, Signal Detect will switch back from low to high (assert point). The assert level is at least 0.5 dB higher than the de-assert level (Signal Detect Hysteresis).

ABSOLUTE MAXIMUM RATINGS

RECOMMENDED OPERATING CONDITIONS

ELECTRICAL INPUT/OUTPUT CHARACTERISTICS

 Transmitter

 Receiver

Note 1) PECL input, internally AC-coupled and terminated

Note 2) Internally DC-coupled.

OPTICAL CHARACTERISTICS

 Transmitter

 Receiver

Note 1) The optical power is launched into SMF .

Note 2) Measured with a PRBS 2²³-1 test pattern @1250Mbps, BER ≤1×10^-10.

Note 3) RSSI DDM working range is between -8 to -28 dBm. RSSI DDM accuracy is better than +/- 3dB for input power levels between -12 to -28 dBm, the accuracy reduces to +/- 5 dBm for other input power levels.

DIAGNOSTIC SPECIFICATION

Figure 1. Digital RSSI Timing

TIMING CHARACTERISTICS FOR RESET

Figure 2 Reset Timing

DIGITAL DIAGNOSTIC MEMORY MAP

The transceivers provide serial ID memory contents and diagnostic information about the present operating conditions by the 2-wire serial interface (SCL, SDA).

The diagnostic information with internal calibration or external calibration all are implemented, including received power monitoring, transmitted power monitoring, bias current monitoring, supply voltage monitoring and temperature monitoring.

The digital diagnostic memory map specific data field defines as following.

PIN DIAGRAM

PIN DESCRIPTIONS

Plug Seq.: Pin engagement sequence during hot plugging.

1) TX Fault is an open collector output, which should be pulled up with a 4.7k~10kΩ resistor on the host board to a voltage between 2.0V and Vcc+0.3V. Logic 0 indicates normal operation; Logic 1 indicates a laser fault of some kind. In the low state, the output will be pulled to less than 0.8V.

2) TX Disable is an input that is used to shut down the transmitter optical output. It is pulled up within the module with a 4.7k~10kΩ resistor. Its states are:

Low (0 to 0.8V): Transmitter on

(>0.8V, < 2.0V): Undefined

High (2.0 to 3.465V): Transmitter Disabled

Open: Transmitter Disabled

3) Mod-Def 0,1,2. These are the module definition pins. They should be pulled up with a 4.7k~10kΩ resistor on the host board. The pull-up voltage shall be VccT or VccR.

Mod-Def 0 is grounded by the module to indicate that the module is present Mod-Def 1 is the clock line of two wire serial interface for serial ID

Mod-Def 2 is the data line of two wire serial interface for serial ID

4) RESET is a LVTTL input. When the previous burst signal package is end, the host will give a “high” RESET to restore the state of LA. Internal pull-down 10K resistor to GND.

5) BSD can track the state of receiving burst signal. Logic 0 indicates loss of signal; Logic1 indicates receiving signal packages.

6) RSSI TRIG is a CMOS input. Assert high after 30ns delay time of the beginning of the monitored burst package at least 300ns in duration.

7) RD-/+: These are the differential receiver outputs. They are internally DC-coupled 100 differential lines which should be terminated with 100Ω (differential) at the user SERDES.

8) TD-/+: These are the differential transmitter inputs. They are internally AC-coupled, differential lines with 100Ω differential termination inside the module.

RECOMMENDED INTERFACE CIRCUIT

PACKAGE DIMENSIONS

ORDERING INFORMATION