2)P沟道 V S D N P GST G
2）P沟道 D G S U U S G D P N+ + P ID N P + VGS=0 VGS=+ VGS=- VDS ID ID VGS VGST
6小信号电路模型(工作在放大区) GS GSO Ds=V Dso tvc 0 D Do t ip=f(vas vps) D DQ OsLo gs DS lO Ol D Ol DDQ GS DS g g gm Ids S
6 小信号电路模型（工作在放大区） ( ) d s m g s d s d s D S Q D g s G S Q D d D D Q d s D S Q D g s G S Q D D G S D S D Q G D D Q d G S GSQ g s D S DSQ d s v g v g v v i v v i i i I v v i v v i i f v v I i i I i v V v v V v = + + = − = + = = + = = + = + = + , 0 rds μνgs vgs vds g d s rds gmνgs vgs g d s vds μ= gm rds
饱和区(放大区) f x”(-Isx)2(1+兄IDs) Oip GS GS一D 1+DsO 2x(1+aVps) 2l 2/ (VGs-VGsT)(1+aVDs) 2/ DO (1+元Ds)
饱和区（放大区） ( ) ( ) ( )( ) ( ) ( ) ( ) D Q ( DSQ ) n o x G S GST D S n o x D S n o x GSQ GST DSQ n o x G S Q D m G S GST D S n o x D I V l C W V V V l C W V l C W V V V l C W v i g V V V l C W I = + − + = + = − + = = − + 1 2 2 1 2 1 2 2 1 1 2 2 2
1=<CW +λV Ql GS GST DS u, Cow g ds ov lo D GSQ GST u, Cow +nvDs GSO GST (1+V DS 几·I DO 1+av DSQ
( ) ( ) ( ) ( ) ( ) ( ) ( ) DSQ D Q D S D S GSQ GST n o x GSQ GST n o x D S Q D d s G S GST D S n o x D V I V V V V l C W V V l C W v i g V V V l C W I + = + + = − = − = = − + 1 1 1 1 2 2