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Diamond Point International

Aitech S940 - 3U CompactPCI Radiation Tolerant Digital I/O Card

Provides a Variety of Discrete TTL, Optoisolated RS422 and RS232 Serial Ports.


Aitech’s S940 Digital I/O card design is based on a variety of discrete TTL, RS422 and opto-isolated. The S940 is designed with a PCI bridge implemented by an anti-fuse FPGA allowing a processor module like S950 to access the Digital I/Os from the cPCI bus.

The S940 provides 12 RS422 outputs and 4 RS422 inputs with state-machines implemented in the FPGA to operate the RS422 channels. The S940 interfaces with typical satellite guidance, navigation and control sensors such as Space Integrated GPS/INS (SIGI), torque rods, solar array drive electronics, separate switches, reaction wheels and payloads with UART interface. The control to these interfaces are
accomplished by memory-mapped software registers designed into the FPGA.

In addition to providing solar array drive electronics current drivers, the three H-bridge circuitry can also be used as motor controllers for other applications. All the RS422 channels can be regrouped and tailored to specific needs by means of modifying the VHDL implementation inside the FPGA.



Features• Designed for LEO, Mars Terrestrial with an Option for GEO Environments
• Single-Slot Conduction-Cooled 3U CompactPCI card
• Twelve RS422 Outputs and Four RS422 Inputs: Space Integrated GPS/INS (SIGI) Interface - Sync Timer and Telemetry Serial Input, Star Tracker: Telemetry Serial Input and Command Serial Output
• Two RS232 UART ports
• Reaction Wheel Tachometer Interface
• Separation Switch Closure Interface
• Three 2A Rated H-Bridge Torque Rod Interface
• Logic Discrete Output Drivers: SADE Pulse Generator and Registered Output
• Two Opto-Isolated Discrete Output Drivers
• Triple-Voted Buffered Memory for Serial Interface
• 33 MHz, 32-bit PCI 2.1 Compliant CompactPCI Interface
• Nominal Power Consumption is Less Than 14 Watts
• Level-2 Components per NASA GSFC 311-INST-001A Specification are available


ExpansionPCI 2.1 Interface Compliant, 32 bit @ 33 MHz PCI Bus Interface
ElectricalS940 typical power consumption is less than 13.5 Watts. The S940 power consumption is estimated as follows:
• +3.3V (+-5%) 0.33A (typical)
• +5V (±5%) 1.28A (typical)
• +12V (±10%) 0.5A (typical)
MechanicalThe S940 is available in a conduction cooled 3U format per VITA 30.1-2002. A custom metal frame provides excellent rigidity, shock resistance and thermal characteristics.
Conformal CoatingConformal optional (series 100), standard (series 200/500). Acrylic or Silicone
TemperatureSeries-100 Lab Grade EDU
• Temperature range (operation): 0 to +55°C
• Temperature range (storage): -40 to +85°C

Series-200 Qual Unit
• Temperature range (operation): -40 to +71°C
• Temperature range (storage): -50 to +100°C

Series-500 Radiation Tolerant Flight Unit
• Temperature range (operation): -40 to +65°C (space vacuum)
• Temperature range (storage): -62 to +125°C

Ruggedization level is determined in the part numbering scheme - refer to datasheet for further details
HumiditySeries-100 Lab Grade EDU: 0-90%
Series-200 Qual Unit: 0-100% (coating as standard)
Series-500 Radiation Tolerant Flight Unit: 0-100% (coating as standard)
VibrationSeries-100 Lab Grade EDU:
• Random (g2/Hz): 20-2000Hz/0.02 g2/Hz
• Sine (g PEAK): 10-100Hz/2g

Series-200 Qual Unit:
• Random (g2/Hz): 20-2000Hz/0.1 g2/Hz
• Sine (g PEAK): 50-500Hz/10g

Series-500 Radiation Tolerant Flight Unit:
• Conduction-cooled: Random (g2/Hz): 20-2000Hz/0.1 g2/Hz
• Conduction-cooled: Sine (g PEAK): 50-500Hz/10g
ShockSeries-100 Lab Grade EDU: 20g/6mS
Series-200 Qual Unit: 40g/11ms, 100g/6ms
Series-500 Radiation Tolerant Flight Unit: 40g/11ms, 100g/6ms (pyro-shock 875g)
Warranty1 Year

Ordering Details

BoardRefer to datasheet for ordering part number scheme