100Gb/s QSFP28 CWDM4 2km Optical Transceiver Module

PHQ28CWDM4

Features

• QSFP28 MSA compliant
• 4 CWDM lanes MUX/DEMUX design
• Supports 103.1Gb/s aggregate bit rate
• 100G CWDM4 MSA Technical Spec Rev1.1
• Up to 2km transmission on single mode fiber (SMF) with FEC
• Operating case temperature: 0 to 70oC
• 4x25G electrical interface (OIF CEI-28G-VSR)
• Maximum power consumption 3.5W
• LC duplex connector
• RoHS compliant

Applications

• Data Center Interconnect
• 100G Ethernet
• Infiniband QDR and DDR interconnects
• Enterprise networking

1.General Description

This product is a transceiver module designed for 2km optical communication applications. The design is compliant to 100GBASE CWDM4 MSA standard. The module converts 4 inputs channels (ch) of 25Gb/s electrical data to 4 CWDM optical signals, and multiplexes them into a single channel for 100Gb/s optical transmission. Reversely, on the receiver side, the module optically de-multiplexes a 100Gb/s input into 4 CWDM channels signals, and converts them to 4 channel output electrical data.

The central wavelengths of the 4 CWDM channels are 1271, 1291, 1311 and 1331 nm as members of the CWDM wavelength grid defined in ITU-T G.694.2. It contains a duplex LC connector for the optical interface and a 38-pin connector for the electrical interface. To minimize the optical dispersion in the long-haul system, single-mode fiber (SMF) has to be applied in this module. Host FEC is required to support up to 2km fiber transmission.

The product is designed with form factor, optical/electrical connection and digital diagnostic interface according to the QSFP28 Multi-Source Agreement (MSA). It has been designed to meet the harshest external operating conditions including temperature, humidity and EMI interference.

2.Functional Description

This product converts the 4-channel 100Gb/s electrical input data into CWDM optical signals (light), by a driven 4-wavelength Distributed Feedback Laser (DFB) array. The light is combined by the MUX parts as a 100Gb/s data, propagating out of the transmitter module from the SMF. The receiver module accepts the 100Gb/s CWDM optical signals input, and de-multiplexes it into 4 individual 25Gb/s channels with different wavelength. Each wavelength light is collected by a discrete photo diode, and then outputted as electric data after amplified by a TIA and a post amplifier. Figure 1 shows the functional block diagram of this product.

A single +3.3V power supply is required to power up this product. Both power supply pins VccTx and VccRx are internally connected and should be applied concurrently. As per MSA specifications the module offers 7 low speed hardware control pins (including the 2-wire serial interface): ModSelL, SCL, SDA, ResetL, LPMode, ModPrsL and IntL.

Module Select (ModSelL) is an input pin. When held low by the host, this product responds to 2-wire serial communication commands. The ModSelL allows the use of this product on a single 2-wire interface bus – individual ModSelL lines must be used.

Serial Clock (SCL) and Serial Data (SDA) are required for the 2-wire serial bus communication interface and enable the host to access the QSFP+ memory map.

The ResetL pin enables a complete reset, returning the settings to their default state, when a low level on the ResetL pin is held for longer than the minimum pulse length. During the execution of a reset the host shall disregard all status bits until it indicates a completion of the reset interrupt. The product indicates this by posting an IntL (Interrupt) signal with the Data_Not_Ready bit negated in the memory map. Note that on power up (including hot insertion) the module should post this completion of reset interrupt without requiring a reset.

Low Power Mode (LPMode) pin is used to set the maximum power consumption for the product in order to protect hosts that are not capable of cooling higher power modules, should such modules be accidentally inserted.

Module Present (ModPrsL) is a signal local to the host board which, in the absence of a product, is normally pulled up to the host Vcc. When the product is inserted into the connector, it completes the path to ground through a resistor on the host board and asserts the signal. ModPrsL then indicates its present by setting ModPrsL to a “Low” state.

Interrupt (IntL) is an output pin. “Low” indicates a possible operational fault or a status critical to the host system. The host identifies the source of the interrupt using the 2-wire serial interface. The IntL pin is an open collector output and must be pulled to the Host Vcc voltage on the Host board.

3.Transceiver Block Diagram

Figure 1. Transceiver Block Diagram

4.Pin Assignment and Description

Figure 2. MSA Compliant Connector

Pin Definition

Notes:

1. GND is the symbol for signal and supply (power) common for QSFP28 modules. All are

common within the QSFP28 module and all module voltages are referenced to this potential

unless otherwise noted. Connect these directly to the host board signal common ground plane.

2. VccRx, Vcc1 and VccTx are the receiver and transmitter power suppliers and shall be applied

concurrently. Recommended host board power supply filtering is shown in Figure 4 below. Vcc

Rx, Vcc1 and Vcc Tx may be internally connected within the QSFP28 transceiver module in any

combination. The connector pins are each rated for a maximum current of 1000mA.

5.Recommended Power Supply Filter

Fiber 12

Fiber 1

Figure 3. Recommended Power Supply Filter

6.Absolute Maximum Ratings

It has to be noted that the operation in excess of any individual absolute maximum ratings might cause permanent damage to this module.

7.Recommended Operating Conditions and Power Supply Requirements

Notes:

1.FEC provided by host system.

2.FEC required on host system to support maximum distance.

8.Electrical Characteristics

The following electrical characteristics are defined over the Recommended Operating Environment unless otherwise specified.

Notes:

1.Vcm is generated by the host. Specification includes effects of ground offset voltage.

2.From 250MHz to 30GHz.

9.Optical Characteristics

Notes:

1.Even if the TDP < 1.0 dB, the OMA min must exceed the minimum value specified here.

2.Hit ratio 5x10-5.

3.The receiver shall be able to tolerate, without damage, continuous exposure to a modulated optical input signal having this power level on one lane. The receiver does not have to operate correctly at this input power.

4.Measured with conformance test signal for BER = 5x10-5.

5.Vertical eye closure penalty, stressed eye J2 jitter, stressed eye J4 jitter, and SRS eye mask definition are test conditions for measuring stressed receiver sensitivity. They are not characteristics of the receiver.

10.Digital Diagnostic Functions

The following digital diagnostic characteristics are defined over the normal operating conditions unless otherwise specified.

Notes:

1. Due to measurement accuracy of different single mode fibers, there could be an additional +/-1 dB fluctuation, or a +/- 3 dB total accuracy.

11.Mechanical Dimensions

Figure 4. Mechanical Outline

13.ESD

This transceiver is specified as ESD threshold 1kV for high speed data pins and 2kV for all others electrical input pins, tested per MIL-STD-883, Method 3015.4 /JESD22-A114-A (HBM). However, normal ESD precautions are still required during the handling of this module. This transceiver is shipped in ESD protective packaging. It should be removed from the packaging and handled only in an ESD protected environment.

14.Laser Safety

This is a Class 1 Laser Product according to EN 60825-1:2014. This product complies with 21 CFR 1040.10 and 1040.11 except for deviations pursuant to Laser Notice No. 50, dated (June 24, 2007).