RAD750 Processor

The RAD750 microprocessor is the radiation-hardened version of the PowerPC 750 microprocessor designed by Motorola and IBM, and manufactured by BAE Systems. Designed for spacecraft use including satellites and avionics, the RAD 750 processor can operate in radiation environments.

Specification

RAD750 and PowerPC 750 Comparison

PowerPC 750	RAD750
Speed: 200 MHz to 266 MHz	Speed: 110 MHz to 133 MHz
Transistors: 6.40-million	Transistors: 10.4-million
Bus Size: 64-bits	Bus Size: 64-bits
Instructions per cycle: 3 (2+branch)	Instructions per cycle: 3 (2+branch)
L1 Cache: 32 K Instructions, 32 K Data	L1 Cache: 32 K Instructions, 32 K Data
L2 Cache: 256 K, 512 K, 1 MB	Optional
Power: 5.7 W at 200 MHz	Power: 5 W at 133 MHz
Die Size: 67 mm × 67 mm	Die Size: 130 mm × 130 mm
Voltage: 3.3 V I/O, 2.6 V core	Voltage: 3.3 V I/O, 2.5 V core
Packaging: 255 pin BGA	Packaging: 360 pin CGA
MTFB:	MTFB: 4.3-million hours

The RAD750 is a circuit-by-circuit translation of the PowerPC 750 processor used on Apple computers. A direct comparison between the two processors shows that the RAD750 has almost double the number of transistors. The additional transistors provide a back up feature, as a part of the radiation hardening process.

Even though RAD750 has more transistors, its power consumption is the same as the non-radiation hardened version, because the additional transistors draw power only when the primary transistor fails.

RAD750 and RAD6000 Comparison

The CPU throughput measured in millions of instructions per second (MIPS) is an indication of performance. In 1996, the RAD6000 could perform 35 MIPS. In 2001, the RAD750 performed between 240 MIPS to 300 MIPS. The RAD750 was the first high performance, 3rd generation CPU available to the spacecraft development community. It was a highly welcomed and much needed processor as previously the only radiation-hardened processor available was the RAD6000.

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