Various designs for MOS transistor-based RF switch topologies for high speed capacitive tuning of oscillators switch circuits include a main switch device comprising a gate connected to a control terminal, a drain connected to a first terminal that is connected to the first capacitor, and a source connected to a second terminal that is connected to the second capacitor. The switch further comprises a first NMOS device having a gate connected to the main switch device gate, a source connected to a ground, and a drain connected to the first terminal. The switch further comprises a second NMOS device having a gate connected to the main switch device gate, a source connected to a ground, and a drain connected to the second terminal. The switch further comprises a pair of PMOS devices each having drains connected respectively to the first and second terminals.