Description

The M.2 loopback module in M-key 2242 NGFF form factor allows you to test the signal integrity of the PCIe lanes of your custom M.2 host board designs. The module is composed of a high-frequency printed circuit board (PCB) designed with controlled impedance traces to loopback each of the 4x PCI Express lanes. The module supports up to PCIe Gen3 (8GHz) and does not have any electronic components.

• Form factor: 2242 NGFF M-key (22mm x 42mm)
• Plugs into M.2 NGFF M-key connectors (normally used for PCIe SSDs)
• Loopback on each of the 4x PCIe lanes PCIe
• Supports PCIe Gen1-3 (2.5GHz to 8GHz)
• Test pads for verification of the 3.3V power input
• No electronic components (bare PCB)

Frequently asked questions

What M.2 NGFF connector will this plug into?

It will plug into any standard M.2 NGFF M-key connector. For an example, please take a look at this connector from TE: 1-2199230-6

What are the electrical requirements of this module?

The M.2 loopback module is completely passive and simply provides loopback connections on each of the 4x PCIe lanes of the M.2 interface. The module does not make use of the 100MHz clock (REFCLK_P/N) that is supplied to M.2 modules, so it does not require that this clock be running. The module does not connect to any of the other signals on the M.2 interface such as PEDET, PERST#, WAKE#, SUSCLK, CLKREQ# etc. The module does connect to some of the 3.3V power input pins to allow verification of this power supply using electrical probes.

Does the loopback module have AC coupling?

No, the module does not have any AC coupling capacitors or any electronic components, it is completely passive. For this loopback module, no AC coupling is necessary on the PCIe lanes because the PCIe M.2 NGFF Electromechanical Specification requires that there be AC coupling capacitors on the PCIe transmit lines of the host device. If you are using this loopback module to test your own custom host PCB, and your host board does not have AC coupling capacitors on the PCIe transmit lines, it is critical that you add the capacitors to the design or you may risk damaging your receiver interface.