diarmuid
Full Member level 2
- Joined
- Aug 4, 2011
- Messages
- 143
- Helped
- 10
- Reputation
- 20
- Reaction score
- 9
- Trophy points
- 1,308
- Location
- Dublin, Ireland
- Activity points
- 2,429
Hello,
So I've read that the body effect increases VT by virtue of VSB > 0. This pulls more -ive ions into
the channel. This increases the amt of gate charge needed to mirror these -ive ions prior to an inversion
layer forming. This increase in the amt of gate charge translates to an increase in VT.
However, what about the dependance of VT on VDB? I presume when VDB > 0 VT increases by virtue of the same
mechanism.
Therefore, for a FET with a large voltage swing at its drain, does its VT value vary with the swing:
- When swing increases, VDB increases, causing VT to increase
- When swing decreases, VDB decreases, causing VT to decrease
Is this correct?
I havent found much material on it on the web so any help / references would be most appreciated.
Thanks,
Diarmuid
So I've read that the body effect increases VT by virtue of VSB > 0. This pulls more -ive ions into
the channel. This increases the amt of gate charge needed to mirror these -ive ions prior to an inversion
layer forming. This increase in the amt of gate charge translates to an increase in VT.
However, what about the dependance of VT on VDB? I presume when VDB > 0 VT increases by virtue of the same
mechanism.
Therefore, for a FET with a large voltage swing at its drain, does its VT value vary with the swing:
- When swing increases, VDB increases, causing VT to increase
- When swing decreases, VDB decreases, causing VT to decrease
Is this correct?
I havent found much material on it on the web so any help / references would be most appreciated.
Thanks,
Diarmuid
