VCA5807 - Fully Integrated, 8-channel, Voltage Controlled Amplifier w/ Passive CW Mixer

The VCA5807 is an integrated Voltage Controlled Amplifier (VCA) specifically designed for ultrasound systems in which high performance and small size are required. The VCA5807 integrates a complete time-gain-control (TGC) imaging path and a continuous wave Doppler (CWD) path. It also enables users to select one of various power/noise combinations to optimize system performance. Therefore, the VCA5807 is a suitable ultrasound analog front end solution not only for high-end systems, but also for portable systems.

The VCA5807 contains eight channels of voltage controlled amplifier (VCA), and CW mixer. The VCA includes Low noise Amplifier(LNA), Voltage controlled Attenuator (VCAT), Programmable Gain Amplifier (PGA), and Low-Pass Filter (LPF). The LNA gain is programmable to support 250 mV_PP to 1 V_PP input signals. Programmable active termination is also supported by the LNA. The ultra-low noise VCAT provides an attenuation control range of 40dB and improves overall low gain SNR which benefits harmonic imaging and near field imaging. The PGA provides gain options of 24 dB and 30 dB. Before the ADC, a LPF can be configured as 10 MHz, 15 MHz, 20 MHz, or 30 MHz to support ultrasound applications with different frequencies. In addition, the signal chain of the VCA5807 can handle signal frequency lower than 100 KHz, which enables it to be used not only in ultrasound applications but also in sonar applications.

The VCA5807 integrates a low power passive mixer and a low noise summing amplifier to accomplish on-chip CWD beamformer. 16 selectable phase-delays can be applied to each analog input signal. Meanwhile a unique 3^rd and 5^th order harmonic suppression filter is implemented to enhance CW sensitivity.

The VCA5807 is available in a 14mm x 14mm, 100-pin TQFP package and it is specified for operation from -40°C to 85°C.

• 8-Channel Voltage Controlled Amplifier
  • LNA, VCAT, PGA, LPF, and CW Mixer
• Programmable Low-Noise Amplifier (LNA)
  • 24/18/12 dB Gain
  • 0.25/0.5/1 V_PP Linear Input Range
  • 0.63/0.7/0.9 nV/rtHz Input Referred Noise
  • Programmable Active Termination
• 40 dB Low Noise Voltage Controlled Attenuator (VCAT)
• 24/30 dB Programmable Gain Amplifier (PGA)
• 3^rd Order Linear Phase Low-Pass Filter (LPF)
  • 10, 15, 20, 30 MHz
  • Butterworth Characteristics
• Noise/Power Optimizations (Full Chain)
  • 99 mW/CH at 0.75 nV/rtHz
  • 56 mW/CH at 1.1 nV/rtHz
  • 80 mW/CH at CW Mode
• Excellent Device-to-Device Gain Matching
  • ±0.5 dB (typical) and ±1.05 dB (max)
• Low Harmonic Distortion
• Fast and Consistent Overload Recovery
• Low Frequency Sonar Signal Processing
• Passive Mixer for Continuous Wave Doppler (CWD)
  • Low Close-in Phase Noise –156 dBc/Hz at 1 KHz off 2.5 MHz Carrier
  • Phase Resolution of 1/16λ
  • Support 32X,16X, 8X, 4X and 1X CW Clocks
  • 12dB Suppression on 3^rd and 5^th Harmonics
  • Flexible Input Clocks
• 14mm x 14mm, 100-pin TQFP