4-Bit ALU
Digital
·
Generic
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Curated by CircuitSim
Details
Manufacturer
Generic
Part number
—
Pins
18
Used in
No circuits
Added
Sep 2026
About this component
Transparent four-bit arithmetic logic unit with eight active-high operations selected by OP2:OP1:OP0. It provides F0–F3 plus Zero, Carry/no-borrow, and signed Overflow flags for undergrad datapath lessons.
Parameters
Logic levels
2 parameters
VTH
Input threshold
Voltage at or above which each operand and opcode input is interpreted as logic high.
2.5 V
VHIGH
High output voltage
Voltage driven for every active logic-high result or flag output.
5 V
Pins
Pins
18 pins
1
A0
Least-significant bit of four-bit operand A.
2
A1
Bit 1 of four-bit operand A.
3
A2
Bit 2 of four-bit operand A.
4
A3
Most-significant and two's-complement sign bit of operand A.
5
B0
Least-significant bit of four-bit operand B.
6
B1
Bit 1 of four-bit operand B.
7
B2
Bit 2 of four-bit operand B.
8
B3
Most-significant and two's-complement sign bit of operand B.
9
OP0
Least-significant opcode bit.
10
OP1
Middle opcode bit.
11
OP2
Most-significant opcode bit.
12
F0
Least-significant result bit.
13
F1
Result bit 1.
14
F2
Result bit 2.
15
F3
Most-significant and two's-complement sign bit of the result.
16
ZERO
Active-high flag indicating F3:F0 equals zero for every opcode.
17
CARRY
Arithmetic carry flag: carry-out for ADD/INC and active-high no-borrow for SUB/DEC; low for Boolean operations.
18
OVERFLOW
Active-high two's-complement signed-overflow flag for arithmetic operations; low for Boolean operations.
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