Session 3 – Honolulu Suite

Analog Devices

Wednesday, June 13, 10:25 a.m.

Chairpersons: J. Paramesh, Carnegie Mellom

M. Ikeda, University of Tokyo

3.1 - 10:25 a.m.

Circuit Techniques to Overcome Class–D Audio Amplifier Limitations in Mobile Devices, X. Jiang, J. Song, M. Wang, J. Chen, S.K. Arunachalam, T. Brooks, Broadcom Corporation

An auxiliary loop with ramping circuits suppresses pop–and–click noise to 1 mV for an amplifier with 4V achievable output voltage. This is the first reported analog technique that can suppress the Class-D pop-and-click due to PWM start/stop and due to the amplifier offset simultaneously. Switching edge rate control enables the system to meet the EN55022 Class–B standard with a 15 dB margin, which is 14 dB better than state-of-the-art designs An enhanced scheme detects short–circuit conditions without relying on over–limit current events. This is the first reported method to detect short-circuit condition with "zero" input signal and before the over-limit current events ever happen. The paper presents an idea to derive a "clock" signal (based on the control signal that connects speak to the battery) to strobe the high-tracking bandwidth comparator. The reported methods enable full adoption of Class-D technology in mobile communication devices.

3.2 - 10:50 a.m.

A 5.2mW, 0.0016% THD up to 20kHz, Ground-Referenced Audio Decoder with PSRR-enhanced Class-AB 16Ω Headphone Amplifiers, S.-H. Wen, C.-C. Yang, MediaTek Inc.

A low-power ground-referenced audio decoder with PSRR-enhanced class-AB headphone amplifiers presents <0.0016% THD in the whole audio band against the supply ripple by a negative charge-pump. Realized in the 40nm CMOS, the fully-integrated stereo decoder achieves 91dB SNDR and 100dB dynamic range while driving a 16Ohm headphone load and consumes 5.2mW from a 1.8V power supply. The core area is 0.093mm2/channel only.

3.3 - 11:15 a.m.

A Sub-1V 3.9µW Bandgap Reference with a 3σ Inaccuracy of ±0.34% from −50°C to +150°C using Piecewise-Linear-Current Curvature Compensation, S. Sano, Y. Takahashi, M. Horiguchi, M.Ota, Renesas Electronics Corporation

A sub-1V 3.9μW bandgap reference (BGR) with small voltage variation of ±0.34% and low temperature drift (< 1mV) over a wide temperature range (−50°C ~ +150°C) and a wide voltage range (+0.9 V ~ +5.5V) by using a low power current mode BGR core and a piecewise-linear curvature compensation system. The BGR occupies 0.1mm2 in 0.13μm CMOS technology with triple well structure.

3.4 - 11:40 a.m.

A 1.2V 8.3nJ Energy-Efficient CMOS Humidity Sensor for RFID Applications, Z. Tan, Y. Chae, R. Daamen*, A. Humbert*, Y. Ponomarev*, M. Pertijs*, Delft University of Technology, *NXP Semiconductors

A CMOS fully-integrated humidity sensor for a RFID sensor platform has been realized in 0.16mm CMOS technology. It consists of a top-metal finger capacitor, covered by a humidity-sensitive polyimide layer, and an energy-efficient inverter-based capacitance-to-digital converter (CDC). Measurements show that the CDC performs a 12.5-bit conversion in 0.8ms while consuming only 8.6uA from a 1.2V supply. Together with the co-integrated humidity sensor, this translates into a resolution of 0.05% RH in the range of 30% RH to 90% RH, at an energy consumption of only 8.3nJ per measurement which is more than an order-of-magnitude less than the state-of-the-art.