On-Chip Hot-Socketing and Power-Sequencing Support

Hot socketing refers to the capability to insert a board into, or remove a board from, a system during operation without causing negative effects to the system or the board. It is also referred to as "hot swapping" or "hot plug-in."

Altera is the only PLD supplier that offers on-chip hot-socketing and power-sequence protection support and characterization proof data for 130-nm and 90-nm FPGA families. The Stratix^®, Stratix GX, Stratix II, Cyclone^®, and Cyclone II FPGA families and the MAX^® 7000AE, MAX 3000A, and the 0.18-µm MAX II CPLD families are designed and tested to offer robust support for on-chip hot-socketing and power-sequence protection without needing additional external devices or board manipulation. The 65-nm Stratix III and Cyclone III FPGA families, as well as the 60-nm Cyclone IV FPGA family, also support on-chip hot socketing and power-sequence protection capability.

To be considered a hot-socketable device, the device must meet three criteria:

• It can be driven before power up without any damage
• It does not drive out before power up
• It does not drive out during power up

To find out more about the advantages of the on-chip hot-socketing support in Altera^® devices, refer to the Altera Hot-Socketing & Power-Sequencing Advantages (PDF) white paper that details Altera’s hot-socketing advantages. For detailed characterization data, refer to the Hot-Socketing & Power-Sequencing Feature & Testing for Altera Devices (PDF) white paper.

For detailed characterization data, refer to the white paper detailing hot-socketing features and testing for the Stratix, Stratix GX, Stratix II, Stratix II GX, Stratix III, Cyclone, and Cyclone II FPGA families and MAX II, MAX 7000AE, and MAX 3000A CPLD families.

Protection in PLDs for High-Availability Systems

Hot socketing is a critical requirement for systems that require high availability (constant system uptime), such as network storage servers or carrier-class telecommunication infrastructures, where each second of system downtime translates directly into revenue losses.

Protection in PLDs for Multi-Voltage Systems

In multi-voltage systems for which hot socketing is not required, hot-socketing and power-sequence protection capability for the PLD is still critical. In these systems, regulators are used to provide different voltage levels and can cause the power-up sequence to become unpredictable; devices that require a predetermined power-up sequence may no longer function properly. 

The hot-socketing support in PLDs can alleviate problems in multi-voltage system designs because normal PLD functionality will not be influenced by the system power-up sequence. This can be vital for the common application where CPLDs are used to control the power up of other devices in very complex systems.

Table 1 outlines some example systems in different market segments that benefit from hot socketing in Altera devices.

On-Chip Hot-Socketing and Power-Sequencing Support Advantages

There are several techniques used to ensure that PLDs function properly during hot socketing, including sequence connectors and discrete hot-swap controllers. Table 2 compares hot socketing in Altera PLDs versus using other techniques.

Notes:

1. For the actual hot-socketing specification for each PLD family, refer to the handbook or data sheet of each respective family.
2. The hot-socketing support in the Stratix, Stratix GX, and Cyclone FPGA families and the MAX 7000AE and MAX 3000A CPLD families is verified against different power-up sequences. Detailed test set up and procedures can be found in the characterization report in the Hot-Socketing & Power-Sequencing Feature & Testing for Altera Devices (PDF) white paper. The Stratix II, Stratix II GX, Stratix III, Stratix IV, Cyclone II, Cyclone III, Cyclone IV, and MAX II device families will also support the hot-socketing feature.
3. The APEX^TM II, APEX 20K, ACEX^® 1K, Mercury^TM, FLEX^® 10KA, FLEX 10KE, and 3.3-V FLEX^® 6000 FPGA families, and the MAX 7000B CPLD family also support hot socketing. For more information, refer to AN 107: Using Altera Devices in Multiple-Voltage Systems (PDF).

Related Links

• Altera Hot-Socketing and Power-Sequencing Advantages (PDF)
• Hot-Socketing and Power-Sequencing Feature & Testing for Altera Devices (PDF)
• Hot-Socketing & Power-On Reset in Stratix IV Devices (PDF) chapter of the Stratix IV Device Handbook
• Hot-Socketing & Power-On Reset in Stratix III Devices (PDF) chapter of the Stratix III Device Handbook
• Hot-Socketing, ESD and Power-On Reset (PDF) chapter of the Stratix II Device Handbook
• Hot-Socketing and Power-On Reset (PDF) chapter of the Cyclone II Device Handbook
• Hot-Socketing, ESD and Power-On Reset (PDF) chapter of the Cyclone III Device Handbook
• Hot-Socketing and Power-On Reset in MAX II Devices (PDF) chapter of the MAX II Device Handbook
• AN 447: Interfacing Cyclone III Devices with 3.3 / 3.0 / 2.5-V LVTL & LVCMOS I/O Systems (PDF)
• AN 107: Using Altera Devices in Multiple-Voltage Systems (PDF)
• Stratix III FPGAs
• Stratix II FPGAs
• Stratix FPGAs
• Stratix GX FPGAs
• Arria II GX FPGAs 
• Arria GX FPGAs 
• Cyclone IV FPGAs 
• Cyclone III FPGAs
• Cyclone II FPGAs
• Cyclone FPGAs
• MAX II CPLDs
• MAX 3000A CPLDs
• MAX 7000 CPLDs