The .GLOBAL statement declares nodes as global, making them visible across subcircuit boundaries. Normally, nodes inside a subcircuit are local and isolated from the parent circuit.
.GLOBAL <node1> [<node2> ...]
* Make power rails global
.GLOBAL VCC GND VDD VSS
Global power rails
.GLOBAL VCC
V1 VCC 0 5
.SUBCKT amp IN OUT
R1 IN BASE 10k
Q1 VCC BASE OUT NPN_MODEL
.ENDS amp
X1 SIG OUTPUT amp
.model NPN_MODEL NPN(Is=1e-14 Bf=100)
.OP
.SAVE V(OUTPUT)
.END
Without .GLOBAL VCC, the VCC node inside the subcircuit would be a separate local node. With .GLOBAL, it refers to the same node as the top-level VCC.
- Ground (node
0) is always global — it does not need to be declared. - Global nodes are useful for power supply rails, clocks, resets, and other signals shared across the entire design.