MAX2087

The MAX2087 is a highly integrated 8-channel ultrasound transceiver that is optimized for high channel density, high performance ultrasound systems.

The octal five-level, high-voltage (HV) pulser device generates high-frequency HV bipolar pulses for driving piezoelectric transducers in ultrasound systems from two independent pairs of HV supplies. Each channel can transmit up to 200Vpp with up to 2A current capability and features an integrated 2A active clamp (Return to Zero). The current capability can be programmed down to 0.4A.

The pulser can be controlled using embedded digital resources (SRAM and state machine) that can be used to support transmit beam-forming resulting in dramatic savings in the number of interconnects and FPGA I/Os. The embedded digital resources are programmed via a high-speed serial interface and supports sophisticated transmit techniques like PWM for burst shaping and apodization for beam shaping.

Alternatively, the device can be controlled in a conventional manner by an external digital source (FPGA) through dedicated CMOS logic inputs.

The MAX2087 also features eight independent low-noise, low-impedance active T/R switches. The highly compact receiver includes LNA, VGA, AAF, ADC, and several digital post-processing circuits (including a digital HPF). It achieves an ultra-low, 2.4dB noise figure at R_S = R_IN = 200Ω at a low 143mW per channel power dissipation when sampling at 50Msps. Additionally, there is a lower power mode of operation that achieves 100mW per channel, but has reduced AC performance. The receive channel has been optimized for second harmonic imaging with -70dBFS second harmonic distortion performance at f_IN = 5MHz over the full TGC range. Dynamic range has also been optimized for exceptional pulsed and color flow Doppler performance under high clutter conditions. The full receive channel exhibits an outstanding 81dBFS SNR at 5MHz with a 2MHz bandwidth. The bipolar front-end and CMOS ADC have also been optimized for an exceptionally low, near-carrier modulation noise of -141dBc/Hz at 1kHz offset from a 5MHz tone for excellent low-velocity Doppler sensitivity.

The device also includes an 8-channel CWD beam-former for a full Doppler solution. Separate mixers for each channel are made available for optimal CWD sensitivity, yielding an impressive 156dBc/Hz dynamic range per channel at 1kHz offset from a 2MHz carrier.

Furthermore, the MAX2087 also contains several digital post-processing options associated with digital mix-to-baseband operation. The device contains a 96dB SNR NCO with a programmable frequency range of 800kHz to 17.6MHz with a < 1kHz resolution. There is also a demodulator circuit followed by a decimating FIR filter that can be programmed for different decimation ratios, where M can be programmed at any integer from 2 to 32. A 16 x M tap lowpass FIR decimation filter is also provided. A post decimation-filter digital gain adjustment is also available.

When mix-to-baseband is used, it is possible to reduce the number of LVDS output lanes required (from 10 pairs to 6 pairs) if decimation rates are ≥ 4.

The MAX2087 is offered in a 23mm x 10mm BGA package with 0.8mm ball pitch, and is specified over a 0°C to +85°C temperature range.

Applications

• Echocardiograph Systems
• Medium and High-Performance Cart-Based Ultrasound Systems
• Medium and High-Performance Portable Ultrasound Systems
• Real-Time 4D Ultrasound Systems
• Shear Wave Elastography Systems