A 0.03 mm2 delta-sigma modulator with cascaded-inverter amplifier

A 7.5‐μW 0.08‐mm2 single‐ended SC delta‐sigma ADC for acoustic sensor applications

“…The quantizer, with its simple structure, has a small size and low power consumption. The simulated results demonstrate that the proposed modulator at a supply voltage of 0.7 V can achieve above a 60-dB SNDR over a wide temperature range from À20°C to 80°C [18]. A feedback-control circuit applies control signals DP and DN for the DAC feedback circuit, as shown in Figure 5.…”

“…However, the output CM voltage of an inverter has to be controlled using additional capacitors and switches, as shown in the dashed box in Figure 2. Wang [18], in particular, adopts the conventional CM technique shown in Figure 2 to control the CM voltage and proposes a cascaded inverter working in the saturation region to achieve a high DC gain and a wide bandwidth. As a result, the output CM voltages are controlled.…”

“…The capacitor C C with different configurations holds the offset voltage V OFF to ensure that the output CM voltages have the same levels at two clock phases. Table I shows a comparison between Wang's approach [18] and the current study. Wang [18], in particular, adopts the conventional CM technique shown in Figure 2 to control the CM voltage and proposes a cascaded inverter working in the saturation region to achieve a high DC gain and a wide bandwidth.…”

“…Power consumption is reduced using inverters [13][14][15][16][17][18] instead of conventional OTAs, to design the delta-sigma ADCs. This is because an inverter with both PMOS-and NMOS-input transistors has a greater transconductance and a large slewing rate [13].…”

“…Wang [18], in particular, adopts the conventional CM technique shown in Figure 2 to control the CM voltage and proposes a cascaded inverter working in the saturation region to achieve a high DC gain and a wide bandwidth. Table I shows a comparison between Wang's approach [18] and the current study. The present work achieves a high circuit simplicity, power efficiency, and size efficiency.…”