Charge Amplifier With an Enhanced Frequency Response for SPM-Based Data Storage

Storage systems based on scanning probe microscopy incorporate an array of thermopiezoelectric cantilevers that require charge amplifiers with a wide frequency response but low power consumption. We use an improved frequency compensation method to enhance the in-band frequency response without requiring any additional power. Measurements show that the prototype chip draws the same 68 A at 1.8 V as an unmodified design but has a closed-loop frequency response that is ten times greater. The chip was fabricated in a 0.18-m standard CMOS process, and the charge amplifier core occupies 0.042 mm2.