The paper presents a very high sensitivity transimpedance amplifier in standard CMOS 0.35 m technology suited for sensing current signals from molecular and nanodevices systems. The circuit, based on an integrator followed by a differentiator configuration, features i) a low-noise time-continuous feedback loop to cope with possible standing currents from the device under test as high as few tens of nA without limiting the signal dynamic range; ii) active current-reducers to implement very high value equivalent resistances of hundreds of G with high linearity irrespective to the current direction and characterized by a shot noise current level (2 ) which is, for low standing current, few orders of magnitude smaller than a physical resistor of equal value and iii) nested-Miller compensation networks to ensure strong stability over a bandwidth of few MHz. Thanks to the ability to draw large standing currents, the circuit is suitable for a use in biological systems where physiological medium is co-present. The measured input equivalent noise of 4 fA Hz at about 100 kHz, recorded when the input dc current is lower than 10 pA, allows the chip to be used, among others, in impedance spectroscopy measurements at the nanoscale with a capability of detecting capacitance variations in sub-attofarad range to cope with the challenges of single-chip instrumentation.

This paper presents a buck-boost dc-dc converter for LED drivers capable of delivering an output current ranging from 0.1to 2 A and a variable output voltage ranging between 2 and 5 V, starting from an input voltage spanning from 2.7 to 5.5 V. The dc-dc converter, realized in a 0.18-μm CMOS technology with 5-V option, occupies an area of 4 mm 2 including pads. The circuit features automatic mode switching and dynamic sizing of the power transistors to achieve a peak efficiency of 91%. With a switching frequency of 2.5 MHz, the achieved line regulation is lower than 0.1% V −1 and the output voltage ripple is less than 10 mV. The obtained turn-on and load transient settling time are lower than 40 μs, thus allowing pulsed operation of the LEDs, as well as switching among LEDs of different colors.

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