When responding to the expected data processing requirements of data centers and artificial intelligence (AI) infrastructures, designers quickly realize that today's connectivity solutions are limited in terms of number of channels, bandwidth, and power supply capabilities.g. Various solutions are also very dispersive in terms of functions, different equipment shapes and connector configurations, and problems such as difficult maintenance, insufficient heat dissipation, and difficulty in upgrading.
The solution to these problems is to use a pluggable multipurpose module (PMM). As described in the Standard SFF-TA-1034 of the SFF TA Technical Working Group of the Storage Network Industry Association (SNIA), the PMM is a standardized module designed to provide high-speed, high-power hardware support for all classical data center applications such as networks, telecommunications, storage, artificial intelligence, and accelerators.
The PMM is designed to support a variety of high-speed data link types, including PCIe and Ethernet, and the next generation SerDes channel using PAM4 signal transmission rates up to 112 gigabit transmission rates per second (GT/s). It also supports solid state drive (SSD), network interface card (NIC) and Compute Express Link (CXL) standards for high-speed connection to memory, accelerator and AI, respectively. PMM unifies the support for all these standards by defining the pin function, position and electrical characteristics in the module.
The PMM is installed in a crate or cabinet that can accommodate multiple PMMs and can process high-speed signals and power supplies through specially designed connectors. The SFF-TA-1037 specification defines these connectors. The challenge for designers is to find a reliable connector supplier that meets this specification.
Known SFF-TA-1037 Connector Supplier
Amphenol's Hyper Cool Edge Series SFF-TA-1037 PMM connectors, which support high-speed data signaling, side-band information transmission, and power connections, can be purchased by designers.
These fine pitch connectors are hot swappable and support a wide variety of board to board and board to wire module applications. These connectors are protocol independent and can be used flexibly in multiple protocol implementations. It operates at 32 GT/s (NRZ) and 64 GT/s (PAM4) and can be upgraded to 112 GT/s (PAM4).
The connector data pins are rated for 29 volts and each pin supports 1.1 amperes (A) of current with a maximum number of pins of 12. The connector body is a black thermoplastic with a flammability rating of UL 94 V-O. The full range of gold-plated contacts provides an operating temperature range of - 40 to 105 ° C.
HE2G15610V10011 is a 158 pin Hyper Cool Edge receptacle that supports 156 signal wires and two power contacts (Figure 1).
Figure 1: HE2G15610V10011 is a 158 pin Hyper Cool Edge socket that supports 156 signal wires and two power connections. Image source: Amphenol)
The connector supports X16 PCIe 5/6 and sideband information transmission. It includes a pair of 200W power contacts suitable for supplying power to CXL supported devices, graphic processors (GPUs) and accelerators.
The pin assignment of this connector is defined according to the signal function (Fig. 2) and is flexible and compatible with various current and future serial standards.
Figure 2 shows the pin assignments for the HE2G15610V10011 158 pin connector. Image source: Amphenol)
For high-speed differential signal lines configured in Ground, Signal, Signal, Ground (GSSG) layout, the pins marked "SIGNAL" in these positions are necessary to ensure the normal operation of these lines. Pins marked "GROUND" are necessary for high speed signal integrity. The pin marked "OPTIONAL" is used for sideband signal or additional power supply.
This surface-mount connector uses copper alloy contacts with a gold plating thickness of 0.76 microns (µ m) (30.0 micro inches (µ in)). Contacts are 0.6 mm (mm) (0.024 in.) apart and include an integral card guide.
Amphenol's HE2G10810V10011 (Figure 3) is a 108-pin dual socket connector that supports an additional 16 send and receive differential signal channels with the same GSSG wiring.
Figure 3: HE2G10810V10011 is a 108-pin socket that can handle 16 additional send and receive signal pairs. Image source: Amphenol)
The connector is a surface mount device with the same mechanical contact geometry and plating as HE2G15610V10011, and 0.6 mm contact spacing. In addition to handling PMM, it supports board to board and board to wire module applications, including SSD, NIC, and CXL.
The third connector in the Amphenol family is the HE0000210V00011 dual contact power outlet (Figure 4). The socket is through-hole mounted, each contact can conduct 34 A current and the output power is 400 watts. Eight 0.65 mm wide, 2 mm pitch contact terminals support rated current.