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Verilog (digital engine)v_dff

D flip-flop

Positive-edge triggered, asynchronous reset (active low)

DCLKnRSTQnQVCCGNDD flip-flop
Schematic symbol

Key data

Category
Logic (Verilog)
Simulation model
Verilog (digital engine)
Reference prefix
U
Pins
7
Land pattern
SOIC-8_3.9mm_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
VCC / GND
Output driver resistance
50 Ω
Verilog source
module dff(input D, CLK, nRST, output reg Q, output nQ);
  always @(posedge CLK or negedge nRST)
    if (!nRST) Q <= 1'b0;
    else Q <= D;
  assign nQ = ~Q;
endmodule

Pins 7

PinNameUse
DDInput pinLogic input: never leave open (tie unused inputs to VCC or GND)
CLKCLKInput pinLogic input: never leave open (tie unused inputs to VCC or GND)
nRSTnRSTInput pinActive-low control input: low = active; tie high when unused
QQOutput pinLogic output: drives the next input; do not tie outputs together
nQnQOutput pinLogic output: drives the next input; do not tie outputs together
VCCVCCSupply pinSupply input: decouple with 100 nF close to the pin
GNDGNDGround pinGround

Parameters 1

Gate delaytpd
Default1n s

Delay per gate / clock→Q

PCB

Generic land patternSOIC-8_3.9mm_P1.27mm

no known land pattern, generic SOIC-8_3.9mm_P1.27mm with pins in symbol order