SPDT

Single pole double throw switch

Library

Junctions

Description

The SPDT block models a single pole double throw switch. The input Simulink® signal, Vctl, controls the transfer of the signal at the input port, In, to one of the two output ports.

If the control voltage is less than the threshold voltage, the block transfers the input signal to output port 1. If control voltage is greater than or equal to the threshold voltage, the block transfers the input signal to output port 2. Two different resistors regulate the conduction path for transfer of input signal from input port to either output port.

The voltage–current relationship at the terminals depends on the relationship between control voltage, Vctl, and the threshold voltage, Vthreshold.

  • If Vctl < Vthreshold:

    Iin=Vin1.Gon+Vin2.GoffI1=Vin1.GonI2=Vin2.Goff+V2.GZ02

  • If VctlVthreshold:

    Iin=Vinout.GoffIout=Vinout.Gon

  • Iin, I1 and I2 — Currents into the input terminal and two output terminals

  • Vin1, Vin2 — Voltages between the input terminal and the output 1 and output 2 terminals, respectively

  • V1, V2 — Voltages at output port 1 and output port 2, respectively

  • Gon, Goff — On and off path conductances

  • GZ01, GZ02 — Shunt port conductances

Parameters

Threshold voltage

Threshold voltage of the switch, specified as a positive scalar. The default value is 0  volts.

Characterization

Characterization of the SPDT switch: Resistance or Insertion loss. The default value is Resistance.

On resistance

On resistance value of the switch, specified as a positive scalar. The default value is 10  ohms. On resistance is available when you set Characterization to Resistance.

Off resistance

Off resistance value of the switch, specified as a positive scalar. The default value is 1e6  ohms. Off resistance is available when you set Characterization to Resistance.

Insertion loss (dB)

Insertion loss value of the switch, specified as a positive scalar. The default value is 1  dB. Insertion loss (dB) is available when you set Characterization to Insertion loss.

Isolation (dB)

Isolation value of the switch, specified as a positive scalar. The default value is 70  dB. Isolation (dB) is available when you set Characterization to Insertion loss

Loading type

Loading type of the SPDT switch: Absorptive or Reflective. The default is Reflective.

Port terminations

Port termination that matches the impedance conditions of the SPDT switch. The default value is 50  ohms.

Note

Port terminations is available when you set the SPDT switch Characterization to Insertion loss or when you set Loading type to Absorptive.

Ground and hide reference terminals

Select this option to internally ground and hide the reference terminals. Clear the option to expose the reference terminals. By exposing these terminals, you can connect them to other parts of your model.

By default, this option is selected.

Introduced in R2015b