Four Terminal Relay (relay)

The four-terminal relay is a voltage controlled relay tied between terminals t1 and t2. The voltage between terminals ps and ns controls the relay resistance. The relay resistance varies nonlinearly between ropen and rclosed, the open relay resistance and closed relay resistance, respectively. These resistance values correspond to control voltages of vt1 and vt2 respectively. The four parameters, vt1, vt2, ropen, and rclosed, can be instance or model parameters.

As an alternative, you can specify the threshold voltage, vth, and the transition width, trans, rather than specifying vt1 and vt2. These two parameters are then calculated from vth and trans: vt1=vth, vt2=vth+trans. If all four parameters are specified, vth and trans override vt1 and vt2. However, the values you specify for 'vt1' and 'vt2' on the instance override any model parameter specifications.

The final model parameter, hysteresis, designates a hysteresis with the on voltage shifted from vth by an amount hysteresis and the off voltage shifted by the same amount in the opposite direction. The direction of shift depends on the sign of trans (or the relative magnitudes of vt1 and vt2): if trans is positive, the on voltage shifts by +hysteresis; if trans is negative (implying that the relay is "normally on"), the on-voltage shifts by -hysteresis.

This device is not supported within altergroup.

Operating conductance is calculated from the instance parameters as follows:

When Vc lies between vt1 and vt2,

G = Gmin + (Gmin - Gmax) * [ 2 * (Vc - vt1)^3

- 3 * (vt2 - vt1) * (Vc - vt1)^2] / (vt2 - vt1)^3

Otherwise, if vt1 < vt2, then

G = Gmin for Vc < vt1 and

G = Gmax for Vc > vt2.

If vt1 > vt2,

G = Gmin   for Vc > vt1 and

G = Gmax   for Vc < vt2.

where Gmin = 1 / ropen, Gmax = 1 / rclosed, and Vc = V(ps) - V(ns).

Sample Instance Statement

rel1 (1 2 ps ns) my_relay ropen=1G rclosed=2

Sample Model Statement

model my_relay relay vt1=2.5 vt2=5 ropen=100M rclosed=0.1

Instance Syntax

Name  1  2  ps  ns ModelName parameter=value ...

Name  1  2  ps  ns relay parameter=value ...

Instance Parameters

vt1 (V)	Relay resistance is ropen at this voltage.
vt2=vt1+1.0 V	Relay resistance is rclosed at this voltage.
ropen=∞ Ω	Resistance of a fully open relay.
rclosed=1.0 Ω	Resistance of a fully closed relay.
m=1.0	Multiplicity factor.
region=off	Estimated operating region. Spectre generates output number (0-1) in a rawfile. Possible values are off or on.
isnoisy=no	Determines if the device should generate noise. Possible values are yes and no.

Model Syntax

model modelName relay parameter=value ...

Model Parameters

vt1 (V)	Relay resistance is ropen at this voltage.
vt2=vt1+1.0 V	Relay resistance is rclosed at this voltage.
ropen=∞ Ω	Resistance of a fully open relay.
rclosed=1.0 Ω	Resistance of a fully closed relay.
hysteresis=0.0 V	Switching Hysteresis.
vth=0.0 V	Threshold Voltage.
trans=0.0 V	Switch Transition Region Width.

Operating-Point Parameters

region=off	Estimated operating region. Spectre generates output number (0-1) in a rawfile. Possible values are off or on.
res (Ω)	Relay resistance.

Related Topics

Distributed Components

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