Date: 16th July 09

 Low-power, high-performance, octal ultrasound front-end IC with programmable CWD

Maxim introduces the MAX2078, the octal ultrasound front-end IC with programmable CWD (continuous-wave Doppler) beamformer.

It combines an active-input-termination LNA, VGA, anti-alias filter, and I/Q mixer CWD beamformer in one fully integrated, monolithic device and targets high-channel-count, cart-based and portable ultrasound medical imaging applications and optimizes the performance.

Maxim claims, this front-end IC delivers the lowest noise and the highest dynamic range of any competing low-power, fully integrated ultrasound front-end and utilizes Maxim's patented mixer-based CWD solution and is fully compliant with all known ultrasound beamforming patents.

The MAX2078 provides an ultra-low-noise, programmable, active-input-impedance LNA to optimize noise figure for a variety of common optimally matched transducer-termination-input impedances at a very low power. Consequently, the device can achieve an impressive full receiver noise figure of only 2.4dB with a 200O input impedance termination, while consuming less than 65mW per channel.

CWD Mixer Close-In, Large-Signal SNR and Linearity Enhance the Detection of Weak, Low-Velocity Blood-Flow Signals.

During the MAX2078's CWD mode of operation, the LO phase dividers within the quadrature mixer array can be programmed to any one of 16 quadrature phases for optimal beamforming resolution. The MAX2078 provides the necessary close-in, large-signal dynamic range and noise performance to detect Doppler shifts ranging from 100kHz to less than 1kHz at optimal sensitivity.

The mixers and LO generators have exceptionally low close-in, large-signal SNR performance of -155dBc/Hz at 1kHz offset from a 200mVP-P, 1.25MHz input clutter signal. This exceptional SNR performance is critical for detecting weak, low-velocity CW Doppler blood-flow signals. The amounts of clutter signal generated in CWD from stationary tissue, bone reflections, and transmit-to-receive crosstalk can be extreme. It is not uncommon for these unwanted signals to be as high as 200mVP-P at the receiver's input. With its excellent close-in SNR performance, the MAX2078 excels in measuring these difficult-to-detect blood-flow signals.

High Integration and Lower Power Allow Increased Channel Densities and Simpler Implementation. And the Ultrasound designs continually migrate toward greater imaging resolution and, therefore, larger channel counts.

The MAX2078 enables higher channel counts in two fundamental ways.

1. By, integrating eight channels within a single chip, Maxim's MAX2078 LNA/VGA/AAF/CWD solution uses very little board space. Virtually all of the necessary circuitry is on the chip.

2. Integration increases circuit functionality. Many ultrasound systems utilize multiple transducer types, which support multiple imaging modes. Each transducer will have unique output impedance. Similarly, multimode transducers have specific output impedances tailored for each mode of operation (e.g., 2D imaging vs. steerable CWD). To facilitate these wide ranges of output impedances, the MAX2078 integrates a unique switchable, input-impedance matching network. Impedances of 50, 100, 200, and 1000O are all supported on this single chip. The input impedance can be switched to optimize the performance of each mode of operation for the system.

 

Package: MAX2078: lead-free 64-TQFP package
                  MAX2077: lead-free 64-TQFP and a space-saving 56-TQFN package

Price: MAX2078: Each $47.50 in 1K pieces
            MAX2077: Each $34.30 in 1K pieces

For further details visit: www.maxim-ic.com/Ultrasound-Front-End