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Verilog (digital engine)74HC244v_hc244

74HC244 (8× tristate bus driver)

74HC244 (8× tristate bus driver): functional Verilog gate model, numbered SOIC pins as in the datasheet.

nOE[0]A[0]Y[7]A[1]Y[6]A[2]Y[5]A[3]Y[4]GNDA[4]Y[3]A[5]Y[2]A[6]Y[1]A[7]Y[0]nOE[1]VCC74HC244
Schematic symbol

Key data

Category
Logic (Verilog)
Simulation model
Verilog (digital engine)
Manufacturer part number
74HC244
Reference prefix
U
Pins
20
Land pattern
SOIC-20W_7.5x12.8mm_P1.27mm

Simulation model

The Verilog source is synthesized to gates with Yosys (WebAssembly) and simulated event by event. Outputs drive the analog circuit like CMOS pins through a driver resistance to the supply; inputs switch at 30 % and 70 % of the supply.

Supply pins
20 / 10
Top module
v_hc244
Output driver resistance
50 Ω
Verilog source

module v_hc244(input [1:0] nOE,input [7:0] A,output [7:0] Y);
assign Y[3:0]=nOE[0]?4'bzzzz:A[3:0];
assign Y[7:4]=nOE[1]?4'bzzzz:A[7:4];
endmodule

Pins 20

PinNameUse
1nOE[0]Input pinActive-low control input: low = active; tie high when unused
2A[0]Input pinLogic input: never leave open (tie unused inputs to VCC or GND)
3Y[7]Output pinLogic output: drives the next input; do not tie outputs together
4A[1]Input pinLogic input: never leave open (tie unused inputs to VCC or GND)
5Y[6]Output pinLogic output: drives the next input; do not tie outputs together
6A[2]Input pinLogic input: never leave open (tie unused inputs to VCC or GND)
7Y[5]Output pinLogic output: drives the next input; do not tie outputs together
8A[3]Input pinLogic input: never leave open (tie unused inputs to VCC or GND)
9Y[4]Output pinLogic output: drives the next input; do not tie outputs together
10GNDGround pinGround
11A[4]Input pinLogic input: never leave open (tie unused inputs to VCC or GND)
12Y[3]Output pinLogic output: drives the next input; do not tie outputs together
13A[5]Input pinLogic input: never leave open (tie unused inputs to VCC or GND)
14Y[2]Output pinLogic output: drives the next input; do not tie outputs together
15A[6]Input pinLogic input: never leave open (tie unused inputs to VCC or GND)
16Y[1]Output pinLogic output: drives the next input; do not tie outputs together
17A[7]Input pinLogic input: never leave open (tie unused inputs to VCC or GND)
18Y[0]Output pinLogic output: drives the next input; do not tie outputs together
19nOE[1]Input pinActive-low control input: low = active; tie high when unused
20VCCSupply pinSupply input: decouple with 100 nF close to the pin

Parameters 1

Gate delaytpd
Default10n

PCB

Verified land patternSOIC-20W_7.5x12.8mm_P1.27mm