资料介绍
CMOS基本放大器设计°ò
MOSFET¤j
1. 2. 3.
°q]-pP¤R °òMOSFET¤j IC MOSFET¤j
8-22¤¤z ]¤Z
°q]-pP¤R
Discrete MOSFET amplifiers°]-p
1. 2. 3.
]° IG=0A qe ]-pC IDM VGSA¤p
¤]-pC
RGq±`¤jb Mδ ≥∫Χβ ICs{í AG°]-p bIC]-p¤¤¤¤¨C
8-23¤¤z ]¤Z
IC MOSFET amplifiers°]-p ICq°]-p¤@¨°ò-ìhG 1. 2. ¤qAhqéAC§Y active loadC ¨qyC
qy¤@¨G¤@Oe-±¨ìLF¤óA±N GSuFt¤@ O¨qyè (current mirror)C °òMOSqyè 1
I REF
IREF¨Mw VGS C
1 W ′ (VGS Vt ) 2 = kn 2 L 1
3
IO =
VGS¨Mw IOC
1 W ′ (VGS Vt )2 kn 2 L 2
2 VGS A -Y¤]b P°òOPs§@A Vt¤] PA k’¤]PAפ]PC Q1M Q2P
IO I REF
=
(W / L)2 (W / L)1
ο∞ι∞Η±±±ο∩ΤΧ
8-24¤¤z ]¤Z
qyèéXS
IO IREF
Slope=1/ro
For Q1 and Q2 are matched.
VGS -Vt
í
VGS
VO
VO ≥VGS -Vt¤§q
¤p°T
IO
Ro
Ro =
VO V = ro 2 = A IO I O
Ro
8-25¤¤z ]¤Z
qyè]-p
I D1 = I D1 =
1 W ′ (VGS Vt ) 2 kn 2 L 1 VDD VGS R ID
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