***** Support us on kickstarter ***** Tiny 5x5cm FPGA board with Xilinx Artix-7

FMCHUB - FAQ

FMC > FAQ


A compilation of practical explanations about
ANSI/VITA 57.1-2008 (R2010), FPGA Mezzanine Card (FMC) Standard



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 a FRU?

6. 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.Molex and Samtec FMC connectors

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 a FRU?

coming soon

6. How can I solder the FMC connector?

coming soon