Multimode 25gb/S Sfp28 Sr 850nm Fiber Optic Transceiver
Description of 25g sfp28 SR module
Sopto 850 nm VCSEL 25Gigabit SFP28 transceiver is designed to
transmit and receive optical data over 50 μm multimode optical
fiber (Table 1).
The SFP28 SR module electrical interface is compliant to SFI
electrical specifications. The transmitter input and receiver
output impedance is 100 Ohms differential. Data lines are
internally AC coupled. The module provides differential termination
and reduce differential to common mode conversion for quality
signal termination and low EMI. SFI typically operates over 200 mm
of improved FR4 material or up to about 150mm of standard FR4 with
one connector.
The transmitter converts 25Gbit/s serial PECL or CML electrical
data into serial optical data compliant with the 25GBASE-SR
standard. An open collector compatible Transmit Disable (Tx_Dis) is
provided. Logic “1”or no connection on this pin will disable the
laser from transmitting. Logic “0” on this pin provides normal
operation. The transmitter has an internal automatic power control
loop (APC) to ensure constant optical power output across supply
voltage and temperature variations. An open collector compatible
Transmit Fault (Tx_Fault) is provided. TX_Fault is module output
contact that when high, indicates that the module transmitter has
detected a fault condition related to laser operation or safety.
The TX_Fault output contact is an open drain/collector and shall be
pulled up to the Vcc_Host in the host with a resistor in the range
4.7-10 kΩ. TX_Disable is a module input contact. When TX_Disable is
asserted high or left open, the SFP28 module transmitter output
shall be turned off. This contact shall be pulled up to VccT with a
4.7 kΩ to 10 kΩ resistor
The receiver converts 25Gbit/s serial optical data into serial
PECL/CML electrical data. An open collector compatible Loss of
Signal is provided. Rx_LOS when high indicates an optical signal
level below that specified in the relevant standard. The Rx_LOS
contact is an open drain/collector output and shall be pulled up to
Vcc_Host in the host with a resistor in the range 4.7-10 kΩ, or
with an active termination. Power supply filtering is recommended
for both the transmitter and receiver. The Rx_LOS signal is
intended as a preliminary indication to the system in which the
SFP28 is installed that the received signal strength is below the
specified range. Such an indication typically points to
non-installed cables, broken cables, or a disabled, failing or a
powered off transmitter at the far end of the cable.
| Fiber type | 850nm OFL Bandwidth | Supported Distances (meters) |
| 50μmMMF | OM4 | 2 to 100 |
| 50μmMMF | OM3 | 2 to 70 |
Table 1: SFP28 SR Operating Range for each Optical Fiber Type
Features of 25g SFP28 SR Module
● 25Gb/s serial optical interface
● 850nm VCSEL transmitter, PIN photo-detector
● Maximum link length of 70m on OM3 MMF and 100m on OM4 MMF
● 2-wire interface for management specifications compliant with SFF
8472 digital diagnostic monitoring interface for optical
transceivers
● Operating case temperature: 0 to 70°C
● All-metal housing for superior EMI performance
● Low power consumption
● Advanced firmware allow customer system encryption information to
be stored in transceiver
● Cost effective SFP28 solution, enables higher port densities and
greater bandwidth
● RoHS compliant
Applications
● 25GBASE-SR Ethernet
● High-speed storage area networks
● Computer cluster cross-connect
● Custom high-speed data pipes
● Inter Rack Connection
Specifications
| Product NO. | SPT-SFP28-SR |
| Wavelength | 850nm |
| Product name | 25g SFP28 module |
| Transmission Distance | 100m |
| Operating temperature | Standard: 0 to +70°C |
| Date rate | 25Gbps |
| Aplications | 25GBASE-SR Ethernet |
| Power supply | Single 3.135~3.465V |
| Package Type | SFP28 |
Optical Characteristics
The following optical characteristics are defined over the
Recommended Operating Environment unless otherwise specified.
| Parameter | Symbol | Min. | Typical | Max | Unit | Notes |
| Transmitter |
| Center Wavelength | λt | 840 | 850 | 860 | nm | |
| RMS spectral width | Pm | | | 0.6 | nm | |
| Average Optical Power | Pavg | -8.4 | | 2.4 | dBm | |
| Optical Power OMA | Poma | -6.4 | -1.5 | 3 | dBm | |
| Laser Off Power | Poff | | | -30 | dBm | |
| Extinction Ratio | ER | 2 | | | dB | |
| Transmitter Dispersion Penalty | TDP | | | 4.3 | dB | |
| Optical Return Loss Tolerance | | | | 12 | dB | |
| Receiver |
| Center Wavelength | λr | 840 | 850 | 860 | nm | |
| Receiver Sensitivity (Average power) | Psens | | -9.5 | | dBm |
BER = 1x10-12
|
| Receiver Sensitivity (OMA) | Psens | | | -10.3 | dBm | BER <5x10-5 |
| Stressed Sensitivity (OMA) | | | | -5.2 | dBm | BER <5x10-5 |
| LOSAssert | LOSA | -30 | | | dBm | |
| LOSDeassert | LOSD | | | -7.5 | dBm | |
| LOS Hysteresis | LOSH | | | | dB | |
| Overload | Pin | 2.4 | | | dBm | Note1 |
| Receiver Reflectance | | | | -7.5 | dB | |
Note:
1. Typical BER is less than 1x10-12, maximum BER is 5x10-5 .
Ordering information
| Part Number | Product Description |
| SPT-SFP28-SR | 25.78Gbps, 850nm SFP28 SR 100m fiber optic module, 0ºC ~ +70ºC |
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