Quad-Channel, Ultra-Low-Noise Amplifier with Digitally Programmable Input Impedance

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 50Ω to 1kΩ. 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 200Ω.

The MAX2034 has excellent dynamic and linearity performance characteristics optimized for all ultrasound-imaging 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 0°C to +70°C temperature range.

Applications

* Sonar Signal Amplification * Ultrasound Imaging

* High-Level Integration of 4 Channels

* Digitally Programmable Input Impedance (RIN) of 50Ω, 100Ω, 200Ω, and 1kΩ

* Integrated Input Clamp

* Integrated Input-Damping Capacitor

* Ultra-Low 2.2dB Noise Figure at RS = RIN = 200Ω

* 70MHz, -3dB Bandwidth

* Low 58mW/Channel Power Dissipation

* HD2 of -68dBc at VOUT = 1VP-P and fIN = 5MHz for Exceptional Second Harmonic Imaging Performance

* Two-Tone Ultrasound-Specific* IMD3 of -55dBc at VOUT = 1VP-P and fIN = 5MHz for Exceptional PW/CW Doppler Performance

* Quick Large-Signal Overload Recovery

* Single +5V Supply Operation

* Sleep Mode