Why Zener diode is used in MOSFET?
In order to protect the gate oxide in the MOSFET and bypass any high ESD voltage, a Zener diode [7] is connected between the gate and source of the dual power MOSFET switch. The aim of the application is to bypass any high peak voltage during the transient time and to provide a weak clamped voltage.
How a Zener diode is formed?
The Zener diode is made up of heavily doped semiconductor material. When the reverse bias applies across the diode and the supply voltage is equal to the Zener voltage then it starts conducting in the reverse bias direction. The Zener voltage is the voltage at which the depletion region completely vanish.
Can you make a Zener diode from a MOS transistor?
You can’t make a Zener diode from a commercial MOS transistor. Zener breakdown (effect) relies on quantum tunneling of electrons trough the thin space-charge region formed in heavily dopped pn junctions [1]. In common MOSFETs, the only heavily dopped regions are the source and drain, while the bulk is usually a lightly dopped p region.
Which is diode between gate and source in N-CH MOSFET?
Re: Zener diode between Gate and Source in N-ch MOSFET. Enough to touch freely? ESD destroys a MOSFET by creating too much voltage between gate and source, which permenently breaks down the gate isolation. The diode prevents this, as long as it is there, so it will work even outside of the circuit.
Is there a Zener diode between gate and source?
Putting a Zener diode between G and S looks like a common technique (among many others http://www.diystompboxes.com/smfforum/index.php?topic=100760.0#msg888061, https://electronics.stackexchange.com/questions/187075/mosfet-gate-source-protection-question ). But does this technique also work when the chip is out of circuit?
Can a MOSFET handle a VNN1 with a Zener?
VNN1 will be -100V. This will make the gate 100V with respect to the source. Most MOSFETs won’t be able to handle that and will burn out (or blow up), or they would if it weren’t for the Zener. The Zener will effectively clamp Vgs at 15V, which the MOSFET WILL be able to handle.