MAX4805A

MAX4805/MAX4805A Octal High-Voltage-Protected, Low-Power, Low-Noise Operational Amplifiers General Description The MAX4805/MAX4805A are octal high-voltage-protected operational amplifiers. These devices are a fully integrated, very compact solution for in-probe amplification of echo signals coming from transducers in an ultrasound system. The use of in-probe buffering improves system signal-to-noise ratio (SNR) for transducers featuring high-output impedance. This results in greater penetration depth and sensitivity. The MAX4805/MAX4805A can be adopted in ultrasound probes without any change in the system (scanner machine). Typical applications include high-impedance piezoelectric transducers (PZT) and capacitive micromachined ultrasonic transducers (CMUT) in-probe buffering and amplification. The MAX4805 is optimized for PZT applications, and the MAX4805A is optimized for CMUT applications. The MAX4805/MAX4805A feature eight operational amplifiers configured in a noninverting configuration. The small-signal output impedance of these operational amplifiers is 65I (typ) for matching the typical cable impedance. The low-noise amplifier features 44MHz (typ) -3dB bandwidth and very low voltage and current noise, ensuring excellent noise figure. The output signals of these operational amplifiers are limited with diodes in an antiparallel configuration to GND. The MAX4805/MAX4805A provide HV protection for inputs and outputs of the operational amplifiers. The operational amplifie...