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4700 Series - Fairchild
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Fairchild 4700 Family
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Developer Fairchild Semiconductor
Manufacturer Fairchild Semiconductor
Type microprocessors
Production 1975
Architecture 4-bit bit-slice
Word size 4 bit
0.5 octets
1 nibbles
Technology CMOS
Clock 2.4576 MHz
Package DIP24, CerDIP24

The 4700 Series (officially 4700 Macrologic Series CMOS Family) was a family of 4-bit CMOS multi-chip bit-slice microprocessor designed by Fairchild Semiconductor. The series was introduced in 1975. Around the same time Fairchild introduced the 9400 series which was a similar family using bipolar technology instead.

2nd Source[edit]

This family was 2nd sourced by Signetics.


Family Members
Part Description
4702 Bit-rate generator
4703 Series/Parallel FIFO (Buffer Memory)
4704 Data Path Switch (DPS)
4705 Microprocessor "ALRS" (Arithmetic Logic Register Stack)
4706 Program Stack
4707 Data Access Register
4708 Microprogram Sequencer
4710 16x4-bit RAM Register Stack
4720 256x1-bit RAM Register Stack
4726 256x4-bit RAM Register Stack
4735 256x8-bit RAM Register Stack


The individual chips were designed such that they may be chained in cascading manner to support any word size desired (usually multiples of 4). The operations themselves are spread throughout the family, for example 16 register manipulations were provided by the DAR (4707), 8 arithmetic by the ALRS (4705), and 30 shifting/masking/extending operation were provided by the DPS (4704).

There is no actual ISA, it was up to the designer to develop one and assemble the chips accordingly.

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See also[edit]

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designerFairchild Semiconductor +
full page namefairchild/4700 +
instance ofmicroprocessor family +
main designerFairchild Semiconductor +
manufacturerFairchild Semiconductor +
nameFairchild 4700 Family +
packageDIP24 + and CerDIP24 +
technologyCMOS +
word size4 bit (0.5 octets, 1 nibbles) +