1. What form factors are specified by ANSI/VITA-57.1?

2. What types of connectors can be used?

3. What's the difference between Molex and Samtec FMC connectors?

4. What EEPROM can be used for FRU information storage?

5. What is the pinout of the FMC connector?

6. What is a FRU?

7. How can I solder the FMC connector?

1. What form factors are specified by ANSI/VITA-57.1?

Firstly, FMC modules are categorized by their width. Single width (69 mm) and double width (139 mm) mezzanine modules are specified. Secondly, they are divided in subtypes according to their cooling layout (air cooled or conduction cooled), mounting style (commercial grade or ruggedized) and module regions (optional region 1 for front panel I/O, region 2 for components, and optional region 3 for rear extension). Not all combinations are possible, a list of suitable form factors is given below.

Width	Mounting	Cooling	Regions	Dimensions (L x W)	Drawings
Single	Commercial grade	Air cooled	2	71.3 mm x 69.0 mm	mechanical layout 3D PCB image
Single	Commercial grade	Air cooled	1, 2	76.5 mm x 69.0 mm	mechanical layout 3D PCB image
Single	Commercial grade	Air cooled	2, 3	78.8 mm x 69.0 mm	mechanical layout 3D PCB image
Single	Commercial grade	Air cooled	1, 2, 3	84.0 mm x 69.0 mm	mechanical layout 3D PCB image
Single	Ruggedized	Conduction cooled	2, 3	78.8 mm x 69.0 mm	mechanical layout 3D PCB image
Single	Ruggedized	Conduction cooled	1, 2, 3	84.0 mm x 69.0 mm	mechanical layout 3D PCB image
Double	...	...	...	... mm x 139.0 mm	coming soon

2. What types of connectors can be used?

The FMC standard specifies a low-pin count (LPC) connector with 160 pins or high-pin count (HPC) connector with 400 pins. An LPC connector on mezzanine card side also fits into an HPC connector on baseboard side. Electrical signals are also compatible, as the LPC pinout is a reduced variant of the HPC pinout. At the moment, there are two major manufacturers for the connectors on baseboard (female) and mezzanine card side (male), Samtec (Samtec FMC connectors) and Molex (Molex FMC connectors). The variants are listed in the table below. The parts marked in bold are most commonly used in ANSI/VITA 57.1 FMC systems.

ANSI/VITA-57 FMC connector	Samtec FMC connector	Molex FMC connector	Description	Mated stack height
CC-LPC-10	ASP-134603-01	45971-4305	female, baseboard side, Low-pin count (LPC), 160 I/O, tin-lead
CC-LPC-10L	ASP-127796-01	45971-4307	female, baseboard side, Low-pin count (LPC), 160 I/O, tin-lead
CC-HPC-10	ASP-134486-01	45971-4315	female, baseboard side, High-pin count (HPC), 400 I/O, lead-free
CC-HPC-10L	ASP-134485-01	45971-4317	female, baseboard side, High-pin count (HPC), 400 I/O, tin-lead
MC-LPC-8.5	ASP-134606-01	45970-4105	male, mezzanine card side, Low-pin count (LPC), 160 I/O, lead-free	8.5 mm
MC-LPC-8.5L	ASP-134605-01	45970-4107	male, mezzanine card side, Low-pin count (LPC), 160 I/O, tin-lead	8.5 mm
MC-HPC-8.5	ASP-134602-01	45970-4115	male, mezzanine card side, High-pin count (HPC), 400 I/O, lead-free	8.5 mm
MC-HPC-8.5L	ASP-134601-01	45970-4117	male, mezzanine card side, High-pin count (HPC), 400 I/O, tin-lead	8.5 mm
MC-LPC-10	ASP-134604-01	45970-4305	male, mezzanine card side, Low-pin count (LPC), 160 I/O, lead-free	10 mm
MC-LPC-10L	ASP-127797-01	45970-4307	male, mezzanine card side, Low-pin count (LPC), 160 I/O, tin-lead	10 mm
MC-HPC-10	ASP-134488-01	45970-4315	male, mezzanine card side, High-pin count (HPC), 400 I/O, lead-free	10 mm
MC-HPC-10L	ASP-134487-01	45970-4317	male, mezzanine card side, High-pin count (HPC), 400 I/O, tin-lead	10 mm

3. What's the difference between Molex and Samtec FMC connectors?

Molex and Samtec FMC connectors are intermateable and interchangeable. A product intermateability specification is available from Molex here and from Samtec here. However, the FMC connectors for mezzanine card side differ in their appearance. The picture below shows Molex FMC connectors and Samtec FMC connectors. We have received the FMC connectors as free samples from Molex and Samtec.

4. What EEPROM can be used for FRU information storage?

In general, any serial EEPROM with I2C interface can be used. The most significant bits of the 7-bit I2C address should be 0b10100xx, where the two least significant bits are determined by the GA[1:0] pins of the FMC connector. Here is a list of commonly used chips we have seen on several FMC modules.

Manufacturer	Part number	Description	Memory size
Microchip	AT24C02D	2k I2C Serial EEPROM	256 x 8bit
Microchip	24AA64	64k I2C Serial EEPROM	8K x 8bit
Microchip	24LC64	64k I2C Serial EEPROM	8K x 8bit
STMicroelectronics	M24C02	2k I2C Serial EEPROM	256 x 8bit

5. What is the pinout of the FMC connector?

The FMC connector Pin Assignments are described here.

6. What is a FRU?

coming soon

7. How can I solder the FMC connector?

coming soon