The MAX2034 four-channel, low-power, ultra-low-noise preamplifier is designed for ultrasound and medical instrumentation applications. Each low-noise amplifier has a single-ended input, differential output, a highly accurate 19dB fixed gain, and a wide -3dB bandwidth of 70MHz. The high-gain accuracy of the amplifier allows for exceptional channel-to-channel gain matching, which is necessary for high-performance ultrasound-imaging applications. The MAX2034 also includes an on-chip programmable input impedance feature that allows the device to be compatible with a variety of common source impedances ranging from 50 to 1k. The input impedance of each amplifier uses a feedback topology for active impedance matching. The active input impedance matching feature achieves an exceptionally low 2.2dB noise figure with a source and input impedance of 200. The MAX2034 has excellent dynamic and linearity performance characteristics optimized for all ultrasoundimaging modalities including second harmonic 2D imaging and continuous wave Doppler. The device achieves a second harmonic distortion of -68dBc at VOUT = 1VP-P and fIN = 5MHz, and an ultrasound-specific* two-tone third-order intermodulation distortion performance of -55dBc at VOUT = 1VP-P and fIN = 5MHz. The MAX2034 is also optimized for quick overload recovery for operation under the large input signal conditions typically found in ultrasound input-buffer imaging applications. The MAX2034 is available in a 48-pin thin QFN package with an exposed paddle. Electrical performance is guaranteed over a 0C to +70C temperature range.