Relationship between common-mode rejection and differential-mode distortion in fully differential Gm-C filters

Choogorn, Terdpun; Mahattanakul, Jirayuth

doi:10.1049/iet-cds.2011.0050

Cited by 2 publications

(5 citation statements)

References 18 publications

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“…Substituting (1) in the Section 2 into (37) yields

V_{od}^{(⟩⟨, 2 ω_{i})} ≃ \frac{h}{4} α V_{id}^{2} (1 - H_{normalc})

According to (34) and (38), the HD2 of the DM output voltage can be found to be

HD 2 = (||, \frac{V_{od}^{(⟩⟨, 2 ω_{i})}}{V_{od}^{(⟩⟨, ω_{i})}}) = α \frac{V_{id}}{2} |h (1 - H_{normalc})|

which is directly dependent on the imbalance ratio α . Likewise, by applying the same condition to (28) and (29), the HD3 of the DM output voltage can be found to be

HD 3 = \frac{V_{id}^{2}}{16} |3 k - h p (4 H_{normalc} - 1)|

It should be noted that HD3 in (40) is the same as the analytical results in [15] whereby the input voltages are assumed to be perfectly balanced, that is, V ic = 0. This is due to the fact that V ic does not have any effect on the HD3.…”

Section: Analysis Of the Ladder Gm‐c Filtersmentioning

confidence: 72%

“…Based on the single-ended CMOS inverter-based transconductor [19] with source degeneration [20], the FD transconductor and CMFB network with structures as shown in Figs. 1b and c have been designed to work under 1 V supply voltage and realised using 0.18 µm CMOS process technology [15]. Subsequently the 3rd-order ladder FD Gm-C low-pass filter ( www.ietdl.org where it can be observed that HD2 is dependent on the value of α.…”

Section: Simulation Resultsmentioning

confidence: 99%

“…where H c is CM gain of the filter, which varies widely with the distribution profiles of the CMFB networks across the filter, whose closed-form expression can be found in [15]. Substituting (1) in the Section 2 into (37) yields…”

Section: Analysis Of the Ladder Gm-c Filtersmentioning

confidence: 99%

“…It should be noted that HD3 in (40) is the same as the analytical results in [15] whereby the input voltages are assumed to be perfectly balanced, that is, V ic = 0. This is due to the fact that V ic does not have any effect on the HD3.…”

Section: Analysis Of the Ladder Gm-c Filtersmentioning

confidence: 99%

“…1 a , the FD transconductor with pseudodifferential structure and its DM and CM half‐circuits are illustrated in Fig. 1 b [15]. Similarly, the CMFB network comprising four inverting transconductors and its DM and CM half‐circuits are shown in Fig.…”

Section: Analysis Of the First‐order Gm‐c Filtermentioning

confidence: 99%

See 4 more Smart Citations

Effects of imbalance input on linearity of pseudodifferential ladder Gm‐C filters

Choogorn

Mahattanakul

2013

IET Circuits, Devices & Systems

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This study presents distortion analysis of the fully differential Gm-C filters in which the imbalance of the differential input voltages is taken into consideration. Closed-form equations expressing distortions of differential-mode (DM) output voltages as functions of DM and common-mode input voltages are developed. It was found that the HD3 of the DM output voltage is independent of the input imbalance. On the contrary, the HD2 of the DM output voltage is directly dependent upon the input imbalance. Simulation results are shown to be in good agreement with the analytical results. Since we are concerned with signals that are composed of several harmonic components, for clarity the phasor representation of each harmonic component will be www.ietdl.org

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“…Substituting (1) in the Section 2 into (37) yields

V_{od}^{(⟩⟨, 2 ω_{i})} ≃ \frac{h}{4} α V_{id}^{2} (1 - H_{normalc})

According to (34) and (38), the HD2 of the DM output voltage can be found to be

HD 2 = (||, \frac{V_{od}^{(⟩⟨, 2 ω_{i})}}{V_{od}^{(⟩⟨, ω_{i})}}) = α \frac{V_{id}}{2} |h (1 - H_{normalc})|

which is directly dependent on the imbalance ratio α . Likewise, by applying the same condition to (28) and (29), the HD3 of the DM output voltage can be found to be