Low Noise Amplifier Development

In house, low-noise amplifier (LNA) circuit is designed for low-noise PMUT PA signal amplification. The heart of this circuit consists of Texas Instrument’s VCA2615 IC for excellent input signal handling capabilities, combining low-noise preamplifier (LNP) and a voltage-gain amplifier (VGA) inside the IC. The differential output of VCA 2615 is buffered using a separate OPA842 op amp in differential amplifier configuration for single-ended output. A power supply is used for the LNA circuit and a DC benchtop power supply is used to control the , which ultimately controls the VGA gain with the linear control response of . G1 and G2 are held high for LNP gain settings as at this setting achieves voltage noise and typically current noise.

pin held low for discrete gain. For limiting the amplified output voltage swing, can be used as an input voltage reference for output clipping to the desired voltage level.