Microsoft PowerPoint - ch25ysk.pptx

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1 Dynamic Analog ircuits (h. 5) 김영석 충북대학교전자정보대학 전자정보대학김영석 5-

2 ontents 5. The MOSFET Switch 5. Fully Differential ircuits 5.3 Switched-apacitor ircuit 전자정보대학김영석 5-

3 5. The MOSFET Switch MOS TG(transmission Gate) is best 0 < THP, NMOS <, PMOS 0 <, TG < < DD DD < DD THN 전자정보대학김영석 5-3

4 ON>OFF MOSFET Switch: harge Injection(I) hannel harge to : No effect due to low impedance of hannel harge to load: lower out (NMOS) But, OFF>ON: No effect due to Rch Q I Δ load ' ox ' ox where Δ load W L ( W L ( THN ' ox GS GS W L ( THN 0 DD THN THN load ) (total charge the channel) ) is nonlear wrt F THN ) / + γ ( φ + φ ) harge Injection: Signal Dependent >Harmonic Distortion F 전자정보대학김영석 5-4

5 MOSFET Switch: apacitie Feedthrough(F) out hange due to apacitie ouplg OFF>ON: No Effect because out is charged to ON>OFF: out hanges due to apacitie ouplg When MOSFET Triode, gsgdox/ When MOSFET Saturation, ti Δ load where DD oerlap oerlap ' ox oerlap + load W LD, LD oerlap length 전자정보대학김영석 5-5

6 Reduction of harge Injection/lock Feedthrough ) Addg Dummy Switch ) Usg MOS TG 3) Usg a Fully Differential ircuitsit 전자정보대학김영석 5-6

7 MOSFET Switch: kt/ Noise Maximum RMS Output Noise from a Simple R ircuit: kt / pf rms 00μ 00 ff 전자정보대학김영석 5-7

8 5.. Sample-and-Hold (SH) ircuits ) Simple SH Sample: S On (H) Hold: S Off (Hout) ) losed-loop SH Sample: S/S3 On, S Off, Hout Hold: S/S3 Off, S On 전자정보대학김영석 5-8

9 SH ircuits 3) losed-loop SH Usg OTA Sample: S On, controlhigh Hold: S Off, controllow No S/S3 SH ) Popular 4) losed-loop SH Usg OTA Sample: S On, S Off, LPF Hold: S Off, S On H at irtual GND: dependent, d Not Nonlear 전자정보대학김영석 5-9

10 out p Ga m op if A om OL A OL is large 5. Fully-Differential ircuits ( p m ) p op MFB m om DD or GND or anythg So, need MFB to set M DD / Merits Mimize i i I/F oupled Noise Rejection Double Output Swg, out.maxdd 전자정보대학김영석 5-0

11 t t t t 5.. A Fully-Differential Sample-and-Hold Operation t ( Sample), t 0, φ Off, OFF t, φ Off, t top top bot OFF OFF, top + + M ( φ ) : Independent of ( Hold), φ On, OFF ( φ ), OFF 3 OFF M const top OFF + OFF + OFF 3 + OFF M ( φ ) : Dependent on 3 ( φ ), OFF ( φ ), OFF 3 ( φ3 ) : M Signal > M Rj Rejected td 전자정보대학김영석 5-

12 Fully-Differential Sample-and-Hold onnectg the Inputs to the Bottom (Poly) Plate Substrate Noise Sees (Sample) or out (Hold) > No effect But, (b) Substrate Noise is coupled to the put of Op-amp 전자정보대학김영석 5-

13 5.3 Switched-apacitor ircuits Switched-capacitor resistor simulates a large alue resistor (>MΩ) ) (,,, q I q high q high Δ φ φ ) ( sc sc ag T R where R T T q I clk sc f 전자정보대학김영석 5-3

14 5.3. Switched-apacitor Integrator Parasitic-Sensitie Integrator No effect p: change transfer function out / s R sc F s I F + p f clk 전자정보대학김영석 5-4

15 Switched-apacitor Integrator Parasitic-Insensitie Integrator Nonertg Inertg on, on, no charge transfer no effect out / s F + + Rsc F s f I clk 전자정보대학김영석 5-5

16 Summg Integrator (b): remoe redundant switches 3 f s f s f s F F F out + 3 f f f clk clk clk 전자정보대학김영석 5-6

17 Lossy Integrator out R R sr3 + sr 4 전자정보대학김영석 5-7

Microsoft PowerPoint - ch07ysk2012.ppt [호환 모드]

Microsoft PowerPoint - ch07ysk2012.ppt [호환 모드] 전자회로 Ch7 CMOS Aplifiers 김영석 충북대학교전자정보대학 202.3. Eail: kiys@cbu.ac.kr k Ch7- 7. General Considerations 7.2 Coon-Source Stae Ch7 CMOS Aplifiers 7.3 Coon-Gate Stae 7.4 Source Follower 7.5 Suary and Additional