Product Overview
A Japanese 8-Bit Microcontroller Pulled From an Accelerometer Terminal Interface
Condition
Condition is Used. This piece is a pull from an accelerometer sensor terminal interface and it is sold untested. Stock is twelve, so the photographed unit is representative of the shelf rather than the individual chip that will be packed for you. In the photos the black plastic body is clean and the top-face marking is crisp: the Hitachi logo, a lot line reading 0E3 Q, then HD637A01V0P and JAPAN. Both rows of pins are straight and bright metal, with no bends, no solder residue and no board debris visible in these photos. Pins that look this clean are ordinary on a socket-pulled IC, so read them as normal warehouse condition rather than as a statement about how long the part ran. The underside carries two molded circular depressions marked ED and 40. Nothing here has been run on a programmer or in a test fixture, and the photos are the spec for the piece shown.
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Product Overview
The HD637A01V0P is a Hitachi 8-bit CMOS microcontroller in a 40-pin plastic dual in-line package, marked JAPAN on the top face beneath the part number and the lot line 0E3 Q. Our record places it in Hitachi's 630x family of 8-bit CMOS single-chip microcontrollers, the CMOS branch of the 6800 and 6801 architecture that Japanese instrument and control builders leaned on heavily through the 1980s and 1990s; no family or series designation is marked on the part itself, so treat that placement as a record entry rather than a marked fact. The body is the standard 40-pin DIP footprint on 0.1 in pin pitch with 0.6 in row spacing, which means it seats in an ordinary 40-pin socket or a through-hole layout without adapters. The unit photographed was pulled from an accelerometer sensor terminal interface, and 1.5 MHz is the speed grade carried in our record for this part number. On-chip memory size, ROM contents, operating mode configuration, supply voltage range and the exact pinout are not confirmed here - verify against the Hitachi datasheet for this exact part number before use. Sold each.
Key Features
- Marked with the Hitachi logo, lot line 0E3 Q, HD637A01V0P and JAPAN on the top face
- 8-bit CMOS microcontroller listed in Hitachi's 630x family per our record - no family designation is marked on the part
- 40-pin plastic dual in-line package, standard 0.1 in pin pitch and 0.6 in row spacing
- Underside molded with two circular depressions marked ED and 40
- Both pin rows straight and bright metal in the photos, no bends or solder residue visible
- Used pull from an accelerometer sensor terminal interface, sold untested
- Sold each from a stock of twelve; the photographed piece is representative
- 1.5 MHz speed grade per our record - not confirmed, verify against the datasheet before use
Applications
- A repair tech keeping a 1980s or 1990s Japanese instrument on the floor when the original 40-pin Hitachi microcontroller has quit and no modern chip is a drop-in.
- A retrocomputing builder who wants a period-correct 630x-family CMOS microcontroller for a hand-wired 40-pin socket instead of a modern substitute behind a translator board.
- A maintenance shop that runs sensor terminal gear and wants the exact Hitachi part number sitting in the spares drawer before a board goes down on a Friday.
- An instructor teaching 8-bit architecture on real silicon, where pulling the chip out of the socket and putting it back is part of the lesson.
Frequently Asked Questions
Has this microcontroller been tested?
No. It is graded by eye from the photos and sold untested. We have not clocked it, powered it, or read it on a programmer, and we make no claim about what is in its memory.
What exactly is marked on the part?
The top face carries the Hitachi logo followed by 0E3 Q on the first line, HD637A01V0P on the second, and JAPAN below that. The underside has two molded circular depressions reading ED and 40. Those molded marks are package and cavity identifiers, not a second part number.
Do I receive the exact chip in the photos?
Not necessarily. Stock is twelve pieces and the photographed unit is representative of that stock. Expect the same part number and package; we do not guarantee an identical lot line on every piece.
Which specifications should I confirm myself?
Memory size and configuration, operating mode selection, supply voltage range, clock requirements and the full pinout are not confirmed here. Pull the Hitachi datasheet for this exact part number and verify against it before you design the chip in.
What am I actually taking on with a used pull like this?
You are taking on the condition risk, and we would rather say so plainly than dress it up. This chip is a used pull from an accelerometer sensor terminal interface, it is sold untested, and the photos are the spec: correct part number and Hitachi logo on a clean plastic body, straight bright pins on both rows, JAPAN under the marking. What you get in exchange is the exact Hitachi part number for a chip that has been out of production for a long time, in a package you can socket and try in an afternoon, instead of gambling on an unlabeled substitute. If your bench can absorb a part that might not come up, this is the honest version of that trade. Shipping is $8 flat rate, free once your order passes $28, and orders leave our Idaho warehouse the same or next business day.
Hitachi's 630x family put a whole 8-bit computer into one 40-pin package, and this one was pulled from an accelerometer terminal interface, the kind of box nobody notices until it stops. It is out of that box now, untested and still marked JAPAN, waiting to find out what your board wants from it.
