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Calculators: Chips: Hitachi Vintage Integrated Circuits

The following page gives an in-depth description of the Hitachi ICs used in vintage calculators listed on this web site. Hitachi semiconductors were used extensively by Hitachi, Casio (and hence re-branded Boots), Sharp and Omron. They were also occasionally used by Decimo, Imperial, Lloytron, Olympia (Panasonic), Sperry (possibly redesigned Casio's) and many others. The Omron ICs were actually renamed but still retained the HD number.

There appears to be a linear numbering system but the switch between four and five digit ID numbers seems random to me. The date code used a {year}{month}{batch} system which used year "0" to progress into 1980.

The logic is conspicuous by the usual lack of overflow recovery (quite annoying when you have to clear the calculator and loose the residual result) and often present Negative Zero Bug. 

Innovative functions like fractions, date calculations and remainder, allowed Casio to issue some pretty unique calculators. The double-operator invoked constant also appears to have been a typical innovation of Hitachi.

Hitachi means, literally, Rising Sun, which explains the sun-like logo that is so familiar to us all.

Notes: Red data is not personally verified by ownership and is information retrieved from other web sites.

Hitachi HD3276P 1972 o Hitachi HD36133 1976 o
Hitachi HD32612P 1974 o Hitachi HD36140 1977 o
Hitachi HD3623        1974 o Hitachi HD37331 1976 o
Hitachi HD3654     1974 o Hitachi HD3780 1977 o
Hitachi HD3633  1975 o Hitachi HD37350 1977 o
Hitachi HD36109 1976 o Hitachi HD37400 1976
Hitachi HD36264 1975 o Hitachi HD37678B 1976
Hitachi HD36265 1976 o Hitachi HD38401 1977 o
Hitachi HD36290 1975 o Hitachi HD38111A 1979 o
Hitachi HD3686 1975 o Hitachi HD38401A 1985
Hitachi HD3692 1975 o

Make and number: Hitachi HD32612P
Package: 40 pin DIL, 0.6” width, black plastic
Known date codes: 4G42
Known date of fabrication: 1974
Calculators: Casio 101-MR
Secondary ICs: 1 x IC: Hitachi HD3596 4J24, 24 pin DIL 0.6" width
Power supply: 6.0V
Display capability:

10 digit + 1(symbol cluster)
Small zero notation
Basic Functions: Four standard plus CE, C, Reverse Polish Notation logic.
Constant: Double operator invoked on multiply and divide only
Dot on symbol cluster shows constant selected
Advanced functions:

percentages, square root
Switch fixed decimal (float/cut/round), switched number of decimals (0/1/2/3/4/6)
Scientific functions: None
Memory: Four function memory (MC) (MR) (M+) (M-)
Indicator for memory storage “M” symbol
Overflow states:

Input overflow is not suppressed
Overflow shows “E” symbol
Zero divisor shows “E” symbol
Overflow recovery: None
Negative sign: Far left symbol cluster
Bugs: Negative square roots allowed
Comments: Early RPN chip which needs heavy support
Make and number: Hitachi HD3623
Package: 42 pin DIL, 0.6” width, black plastic
Known date codes: 4J21
Known date of fabrication: 1974
Calculators: Sharp EL-8002
Secondary ICs: None
Power supply: 4.5V
Display capability: 8 digit + 1
Basic Functions: Four standard plus CE, C
Constant: Automatic on multiply and divide only
Advanced functions: Percentages
Scientific functions: None
Memory: None
Overflow states:

Input overflow is suppressed
Overflow shows ".......0.C."
Zero divisor shows ".......0.C."
Overflow recovery: None
Negative sign: Far right (first) digit
Bugs: Negative zero bug
Comments: Odd far right symbols for negative and overflow indication
Make and number: Hitachi HD3654
Package: 36 pin DIL, 0.6” width, black plastic
Known date codes: 4K12
Known date of fabrication: 1974
Calculators: Casio Mini Memory
Secondary ICs: None
Power supply: 6.0V
Display capability:

8 digit + 0, with display shift capability
Small zero notation
Basic Functions: Four standard plus CE, C
Constant: None
Advanced functions: Percentages, display shift
Scientific functions: None
Memory:

Switched accumulation memory
Three function memory (=) will add, (=) will decrement and (T) to recall (C) clears memory
No indication of memory store
Overflow states:

Input overflow is suppressed
Overflow shows 16 digits of answer in right hand (first) digit
Zero divisor is ignored with zero result
Overflow recovery: None
Negative sign: Immediate left hand digit that disappears on overflow
Bugs: None
Comments: 16-digit precision displayed using the shift key (>) makes up for this simplistic early IC.
Make and number: Hitachi HD3633
Package: 40 pin DIL, 0.6” width, black plastic
Known date codes: 5B21
Known date of fabrication: 1975
Calculators: Lloyd's Accumatic 30 (EH-9036), Elite 3001, Decimo Vatman (black)
Secondary ICs: None
Power supply: 6.0V
Display capability:

8 digit + single LED, but in the Decimo and Elite calculators it uses a 8+1 digit display to show minus and error signs.
Basic Functions: Four standard plus CE, C
Constant: Automatic on multiply and divide only
Advanced functions: Percentages
Scientific functions: None
Memory:

None
Overflow states:

Input overflow is suppressed
Overflow shows result and hooks up
Zero divisor shows zero and hooks up
Overflow recovery: None
Negative sign: Single LED (or ninth digit)
Bugs: Negative zero bug
Comments: Interesting to see this used in eight and nine digit display models.
Make and number: Hitachi HD36109
Package: 36 pin DIL, 0.6” width, black plastic
Known date codes: 6F11
Known date of fabrication: 1976
Calculators: Ibico 0892
Secondary ICs: None
Power supply: 3.0V
Display capability:

8 digit + 1 normal mode
5 digit + 2 scientific mode
Basic Functions: Four standard plus CE/C
Constant: Automatic on all four functions
Advanced functions: change sign, pi, register exchange, reciprocal, square root
Scientific functions: Trigonometric functions, transcendental functions, DMS input, switched DR mode and exponents.
Memory:

Three function memory (MC) (MR) (M+)
Indication of memory store with a “u” in the far left (ninth) digit
Overflow states:

Input overflow is suppressed
Overflow shows result and “E0.” in the far left
Zero divisor shows zero and “E0.” in the far left
Negative roots tbd
Overflow recovery: Overflow is recoverable using (CE), other error states are not
Negative sign: Far left (ninth) digit shows upper segment “-“ whilst third digit shows normal “-“ for exponents
Bugs: tbd
Comments: Number input from the left hand side
Make and number: Hitachi HD36264
Package: 28 pin DIL, 0.6" width black plastic
Known date codes: 5K13
Known date of fabrication: 1975
Calculators: Canon LD-8M2
Secondary ICs: None
Power supply: 3.0V
Display capability: 8 digit + 1
Basic Functions: Four standard plus CE, C
Constant: Automatic on multiply and divide
Advanced functions: Percentages, Square root
Scientific functions: None
Memory: Four function (MC) (MR) (M+) (M-)
Memory store indicated by double line on 9th digit
Overflow states: Input overflow is suppressed
Overflow shows result and "E" in 9th
Zero divisor shows zero and "E" in 9th
Negative square roots show result and "E" in the 9th
Overflow recovery: None
Negative sign: Shown in the 9th (far left) digit
Bugs: None
Comments: Robust but lacks recovery
Make and number: Hitachi HD36265
Package: 24 pin DIL, 0.6” width, black plastic
Known date codes: 6B43
Known date of fabrication: 1976
Calculators: Imperial 91S
Secondary ICs: None
Power supply: 6.0V
Display capability: 8 digit + 1
Basic Functions: Four standard plus CE, C
Constant: Automatic on all four functions
Advanced functions:

percentages, sign change, register exchange, pi, square root
Switch floating or fixed decimal point (F/3/2)
Scientific functions: None
Memory:

Four function memory (MC) (MR) (M+) (M-)
Indication of memory store with a double line in far left (ninth) digit
Overflow states:

Input overflow is suppressed
Overflow shows result and “E” in right symbol cluster
Zero divisor shows zero and “E” in right symbol cluster
Negative roots show result and “E” in right symbol cluster
Overflow recovery: None
Negative sign: Far left (ninth) digit shows “-“
Bugs: tbd
Comments:
Make and number: Hitachi HD36133
Package: 28 pin DIL, 0.6” width, black plastic
Known date codes: 6G31
Known date of fabrication: 1976
Calculators: Casio AL-8S
Secondary ICs: None
Power supply: 3.0V
Display capability: 8 digit + 0
Basic Functions: Four standard plus CE, C
Constant: Double operator invoked on all four functions
Advanced functions: Percentages, square root, fractions, dates and remainder Switched fixed decimal point (float/cut/round 2 digit)
Scientific functions: None
Memory:

Accumulating memory with five functions (MC) (MR) (M+) (M-) and (GT) for grand total
No indication of memory store
Overflow states:

Input overflow is suppressed
Overflow shows result only
Zero divisor shows “E” in the far right (first digit)
Negative square roots tbd
Overflow recovery: None
Negative sign: Immediate left digit but no ninth to travel into
Bugs: Negative zero bug
Comments: Date functions are not Y2K compliant.  Interesting extra functions and one of the first fraction ICs.
Make and number: Hitachi HD37331
Package: 28 pin DIL, 0.6” width, black plastic
Known date codes: 6G13
Known date of fabrication: 1976
Calculators: Sharp EL-8018, EL-201
Secondary ICs: None
Power supply: 3.0V
Display capability: 8 digit + 1
Basic Functions: Four standard plus CE/C
Constant: Automatic on multiple and divide only
Advanced functions: Percentages, square root, sign change
Scientific functions: None
Memory:

One function memory (T), auto accumulation on (=) key
(C/CE) twice or (T) twice clears memory
No indication of memory store
Overflow states:

Input overflow is suppressed
Overflow shows result and  “C” or “E” in right hand (first) digit
Zero divisor shows zero and “C” in right hand (first) digit
Negative roots show result and “E” in right hand (first) digit
Overflow recovery: Only for overflow – use (C/CE)
Negative sign: Far right (first) digit
Bugs: Negative zero bug
Comments: Odd far right symbols for negative and overflow indication
Make and number: Hitachi HD36140
Package: 42 pin DIL, 0.6” width, black plastic
Known date codes: 1977
Known date of fabrication: 7D35
Calculators: Canon F-71
Secondary ICs: Hitachi HD36141 7D13, 16 pin DIL, 0.6" width black plastic
Power supply: 6.0V
Display capability: 10 digit + 1 standard, 10/2+2 scientific
Basic Functions: Four standard plus CE, C
Constant: Automatic on multiply and divide only
Advanced functions: Change sign, square root, squares, powers, reciprocal, factorial,  pi,   Three function, five store memory.
Scientific functions: Polar-rectangular conversion, DMS, trigonometric and transcendental functions, extensive statistical functions, DRG switch, Stat mode switch (n/n-1), further switch (X/XY/LR)
Memory:

Five memory locations, three function (CMn), (RMn), (Mn+)
No indication of memory store
Overflow states:

Input overflow is suppressed
Overflow shows only "E0."
Zero divisor shows only "E0."
Negative square roots shows only "E0."
Overflow recovery: None
Negative sign: Far left (fourteenth) digit for standard numbers, third digit for exponent
Bugs: No major bugs but accuracy has a poor reputation on the higher functions
Comments: Sophisticated chip which requires a companion IC which is also oddly 0.6" width.
Make and number: Hitachi HD3780
Package: 28 pin DIL, 0.6” width, black plastic
Known date codes: 7F13
Known date of fabrication: 1977
Calculators: Casio Personal M1 (H-813)
Secondary ICs: None
Power supply: 3.0V
Display capability: 8 digit + 0
Basic Functions: Four standard plus CE, C
Constant: Double operator invoked on all four functions
Advanced functions: Square root, percentages
Scientific functions: None
Memory:

One function memory (MR)
Auto accumulation on (=) key
(C) clears memory
No indication of memory store
Overflow states:

Input overflow is suppressed
Overflow shows “E” in right hand (first) digit
Zero divisor shows “E” in right hand (first) digit
Overflow recovery: None
Negative sign: Immediate left hand digit
Bugs:

Limit of 7 digit negative numbers
Negative roots result in a negative number
Negative zero bug
Comments:
Make and number: Hitachi HD37350
Package: 28 pin DIL, 0.6” width, black plastic
Known date codes: 7E33
Known date of fabrication: 1977
Calculators: Adler 81CS type II
Secondary ICs: None
Power supply: 3.0V
Display capability: 8 digit + 1
Basic Functions: Four standard plus CE/ C
Constant: Automatic on multiply and divide
Advanced functions: Percentages, delta percent, square root, pi, Xn, reciprocal, sign change.
Switch decimal display (cut/round), switched number of decimals (F/0/2/3)
Scientific functions: None
Memory: Switched accumulation memory
Three function (MR) (M+) (M-)
Memory store indicated by 9th digit decimal point
Overflow states:

Input overflow is suppressed
Overflow shows result and C or E
Zero divisor shows zero and C
Negative square roots show result and E
Overflow recovery: CE/C will recover all except divide by zero
Negative sign: Negative sign in ninth digit
Bugs: None discovered
Comments: Quite robust.
Make and number: Hitachi HD38401
Package: 36 pin DIL, 0.6” width, black plastic
Known date codes: 7F35
Known date of fabrication: 1977
Calculators: Sharp CS-2109, Canon Canola L3 (1980), Triumph Adler 1217 (a later version of which uses the HD38401A)
Secondary ICs: None
Power supply: Unsure – mains powered model but the Canon is 6.0V
Display capability: 12 digit + 2(symbol clusters), upper commas for thousand separators
Basic Functions: Four standard plus CE, C, “00” input
Constant: Switched on multiple and divide only
Advanced functions:

Percentages, square root, register exchange, mark up, delete
Switched round up, cut and down
Switched floating or fixed or financial input (F/6/3/2/1/0/A)
Scientific functions: None
Memory:

Five function memory (MC) (MR) (M+) (M-) (CT) count total
Switched accumulation mode
Indication of memory store with a symbol on the far right
Overflow states:

Input overflow is not suppressed
Overflow shows result and “E” in right symbol cluster
Zero divisor shows zero and “E” in right symbol cluster
Negative roots show result and “E” in right symbol cluster
Overflow recovery: Divide by zero is not recoverable whilst input and calculation overflow and root errors are with either (CE) or the (->) delete key
Negative sign: Far left symbol cluster
Bugs: tbd
Comments: Obviously designed for the desktop market with lots of financial functions
Make and number: Hitachi HD38111A
Package: 28 pin DIL, 0.6” width, black plastic
Known date codes: 9F33, 0B33, 1A23
Known date of fabrication: 1979 - 1981
Calculators: Boots 425 Scientific, Casio FX-31, FX-39, FX-140
Secondary ICs: None
Power supply: 3.0V
Display capability: 8 digit + 1 standard mode
6 digit + 2 in scientific mode
It is capable of 10 + 1 digit display as in the Casio FX-140
Basic Functions: Four standard plus CE, C
Constant: Double operator invoked on all four functions
Advanced functions:

Square root, percentages, change sign, reciprocal, squares, pi
Trigonometric functions, transcendental functions, powers and nth root, statistical functions, factorial, six level brackets, DMS input and display, switched DRG mode.  Also fractions and register/memory exchange (not verified).
Scientific functions:

None
Memory: Two function memory (Min) (MR)
No memory clear
No indication of memory store
Overflow states:

Input overflow is suppressed
Overflow shows “E” in right hand (first) digit
Zero divisor shows “E” in right hand (first) digit
Overflow recovery: None
Negative sign: Immediate left hand digit travelling into ninth
Bugs: None
Comments: Internal 10-digit precision.  It appears to be the same IC that is used in the 10-digit Casio FX-140 that swaps the reciprocal and factorial key for a fractions and register/memory exchange key.  This is not personally verified.
Make and number: Hitachi HD38401A
Package: 36 pin DIL, 0.6” width, black plastic
Known date codes: 5J45
Known date of fabrication: 1974-5
Calculators: Casio J-20
Secondary ICs: None
Power supply: 3.0V
Display capability: 10 digit + 1 standard mode
Basic Functions: Four standard plus CE, C
Constant: Automatic on multiply and divide only
Advanced functions:

Square root, percentages, mark-up/down.
Switched floating/cut/round, switched 4/2/1/0 fixed decimal.
Scientific functions:

None
Memory: Four function memory (MRC) (M+) (M-)
Memory store indicated by eleventh digit
Overflow states:

Input overflow not suppressed
Overflow shows “C” or "E" in left hand (eleventh) digit
Zero divisor shows “C” in left hand (eleventh) digit
Overflow recovery: Full using (CE)
Negative sign: Far left hand (eleventh) digit
Bugs: None
Comments: No bugs found