PA-7200
| Company type | Microprocessor |
|---|---|
| Industry | Semiconductor |
| Founded | 1995 |
| Founder | Hewlett-Packard |
| Products | Microprocessors |
The PA-7200, also identified as PCX-T and internally referred to by the codename Thunderbird, is a microprocessor that implements the PA-RISC 1.1 instruction set architecture (ISA) created by Hewlett-Packard (HP). Released in early 1995, it was initially integrated into HP's own systems and was not commercially available for open sale; notable external adopters included Convex Computer and Stratus Computer, both participants in the Precision RISC Organization (PRO). Designed primarily for compact multiprocessing configurations featuring two or four CPUs, the PA-7200 was unveiled at Compcon as well as at the IEEE International Solid-State Circuits Conference (ISSCC).
Description
Building largely upon the foundation of the PA-7100, the PA-7200 introduced a second integer execution unit, which allowed it to dispatch up to two integer instructions within a single clock cycle. This additional unit specialized in handling simpler, more commonly executed instructions. The chip comprised approximately 1.3 million transistors and had physical dimensions of 14.0 mm by 15.0 mm, resulting in a die area of 210 mm2. Manufactured by HP using their CMOS14A fabrication process—developed in collaboration with Analog Devices—this 0.55 μm technology featured a three-level interconnect and utilized complementary metal–oxide–semiconductor (CMOS) methods to enhance overall performance.
Due to limitations inherent in the manufacturing process, the microprocessor operates on an unconventional 4.4 V power supply. Originally designed with a 0.8 μm CMOS26B process that incorporated circuits from the PA-7100, it was subsequently miniaturized to the CMOS14A process, which could not support standard 5.0 V operation. While a 3.3 V supply would have restricted the achievable clock speed, the choice of 4.4 V represented an optimal balance to satisfy performance requirements.
References
- Chan, Kenneth K.; et al. (February 1996). "Design of the HP PA 7200 CPU". Hewlett-Packard Journal, February 1996.
- Gwennap, Linley (7 March 1994). "PA-7200 Enables Inexpensive MP Systems". Microprocessor Report, Volume 8, Number 3.
- Pountain, Dick (August 1994). "A Different Kind of RISC". Byte.
- PA-7200 PA-RISC Processor OpenPA.net
Further reading
- Rashid, E.; et al. (1994). "A CMOS RISC CPU with on-chip parallel cache". ISSCC Digest of Technical Papers.