Medical Ultrasound

The AD8334 is an ultralow noise, quad channel linear-in-dB variable gain amplifier (VGA). Although optimized for ultrasound systems, it may be used as a low noise variable gain control in any application whose operating frequency is less than 100 MHz.

Included in each channel are an ultralow noise preamp (LNA), an X-AMP^® VGA with 48 dB of gain range, and a selectable gain postamp with adjustable output limiting. The LNA gain is 19 dB with a single-ended input and differential outputs. Using a single resistor, the LNA input impedance can be adjusted to match a signal source without compromising noise performance.

The 48 dB gain range of the VGA makes these devices suitable for a variety of applications. Excellent bandwidth uniformity is maintained across the entire range. The gain control interface provides precise linear-in-dB scaling of 50 dB/V for control voltages between 40 mV and 1 V. Factory trim ensures excellent part-to-part and channel-to-channel gain matching. Differential signal paths result in superb second- and third-order distortion performance and low crosstalk.

The AD8334 is a quad version of the single AD8331 and dual AD8332.

For information on specs, see the AD8331/AD8332/AD8334 datasheet.

Applications

• Ultrasound and sonar time-gain controls
• High performance automatic gain control (AGC) systems
• I/Q signal processing
• High speed, dual ADC drivers

The AD8264 is a quad, linear-in-dB, general-purpose, variable gain amplifier (VGA) with a preamplifier (preamp), and a flexible differential output buffer. DC coupling, combined with wide bandwidth, makes this amplifier a very good pulse processor. Each channel includes a single-ended input preamp/VGA section to preserve the wide bandwidth and fast slew rate for low distortion pulse applications. A 6 dB differential output buffer with common-mode and offset adjustments enable direct coupling to most modern high speed analog-to-digital converters (ADCs), using the converter reference output for perfect dc matching levels.

The −3 dB bandwidth of the preamp/VGA is dc to 235 MHz, and the bandwidth of the differential driver is 80 MHz. The floating gain control interface provides a precise linear-in-dB scale of 20 dB/V and is easy to interface to a variety of external circuits. The gain of each channel is adjusted independently, and all channels are referenced to a single pin, GNLO. Combined with a multioutput, digital-to-analog converter (DAC), each section of the AD8264 can be used for active calibration or as a trim amplifier.

Operation from a bipolar power supply enables amplification of negative voltage pulses generated by current-sinking pulses into a grounded load, such as is typical of photodiodes or photomultiplier tubes (PMT). Delay-free processing of wideband video signals is also possible.

Applications

• Multichannel data acquisition
• Positron emission tomography
• Gain trim
• Industrial and medical ultrasound
• Radar receivers

The AD9671 is designed for low cost, low power, small size, and ease of use for medical ultrasound applications. It contains eight channels of a VGA with an LNA, a CW harmonic rejection I/Q demodulator with programmable phase rotation, an AAF, an ADC, and a digital demodulator and decimator for data processing and bandwidth reduction.

Each channel features a maximum gain of up to 52 dB, a fully differential signal path, and an active input preamplifier termination. The channel is optimized for high dynamic performance and low power in applications where a small package size is critical.

The LNA has a single-ended to differential gain that is selectable through the serial port interface (SPI). Assuming a 15 MHz noise bandwidth (NBW) and a 21.6 dB LNA gain, the LNA input SNR is 94 dB. In CW Doppler mode, each LNA output drives an I/Q demodulator that has independently programmable phase rotation with 16 phase settings.

Power-down of individual channels is supported to increase battery life for portable applications. Standby mode allows quick power-up for power cycling. In CW Doppler operation, the VGA, AAF, and ADC are powered down. The ADC contains several features designed to maximize flexibility and minimize system cost, such as a programmable clock, data alignment, and programmable digital test pattern generation. The digital test patterns include built-in fixed patterns, built-in pseudorandom patterns, and custom user defined test patterns entered via the SPI.

Applications

• Medical imaging/ultrasound
• Nondestructive testing (NDT)

The AD9675 is designed for low cost, low power, small size, and ease of use for medical ultrasound. It contains eight channels of a variable gain amplifier (VGA) with a low noise preamplifier (LNA), a continuous wave (CW) harmonic rejection I/Q demodulator with programmable phase rotation, an antialiasing filter (AAF), an analog-to-digital converter (ADC), and a digital high-pass filter and RF decimation by 2 for data processing and bandwidth reduction.

Each channel features a maximum gain of up to 52 dB, a fully differential signal path, and an active input preamplifier termination. The channel is optimized for high dynamic performance and low power in applications where a small package size is critical.

The LNA has a single-ended to differential gain that is selectable through the serial port interface (SPI). Assuming a 15 MHz noise bandwidth (NBW) and a 21.6 dB LNA gain, the LNA input SNR is 94 dB. In CW Doppler mode, each LNA output drives an I/Q demodulator that has independently programmable phase rotation with 16 phase settings.

Power-down of individual channels is supported to increase battery life for portable applications. Standby mode allows quick power-up for power cycling. In CW Doppler operation, the VGA, AAF, and ADC are powered down. The ADC contains features to maximize flexibility and minimize system cost, such as a programmable clock, data alignment, and programmable digital test pattern generation. The digital test patterns include built-in fixed patterns, built-in pseudorandom patterns, and custom user-defined test patterns entered via the SPI.

Applications

• Medical imaging/ultrasound
• Nondestructive testing (NDT)

The AD9106 TxDAC^® and waveform generator is a high performance, quad digital-to-analog converter (DAC) integrating on-chip pattern memory for complex waveform generation with a direct digital synthesizer (DDS). The DDS is a 12-bit output, up to 180 MHz master clock sinewave generator with a 24-bit tuning word allowing 10.8 Hz/LSB frequency resolution. The DDS has a single frequency output for all four DACs and independent programmable phase shift outputs for each of the four DACs.

SRAM data can include directly generated stored waveforms, amplitude modulation patterns applied to DDS outputs, or DDS frequency tuning words.

An internal pattern control state machine allows the user to program the pattern period for all four DACs as well as the start delay within the pattern period for the signal output on each DAC channel.

Registers accessed using the serial peripheral interface (SPI) configure the digital waveform generator and load patterns into the SRAM.

There are gain adjustment factors and offset adjustments applied to the digital signals on their way into the four DACs.

The AD9106 offers exceptional ac and dc performance and supports DAC sampling rates up to 180 MSPS. The flexible power supply operating range of 1.8 V to 3.3 V and low power dissipation of the AD9106 make it well suited for portable and low power applications.

Applications

• Medical instrumentation
  • Ultrasound transducer excitation
• Portable instrumentation
  • Signal generators, arbitrary waveform generators

The AD9510 provides a multi-output clock distribution function along with an on-chip phase-locked loop (PLL) core. The design emphasizes low jitter and phase noise to maximize data converter performance. Other applications with demanding phase noise and jitter requirements also benefit from this device.

The PLL section consists of a programmable reference divider (R); a low noise, phase frequency detector (PFD); a precision charge pump (CP); and a programmable feedback divider (N). By connecting an external voltage-controlled crystal oscillator (VCXO) or voltage-controlled oscillator (VCO) to the CLK2 and CLK2B pins, frequencies of up to 1.6 GHz can be synchronized to the input reference.

There are eight independent clock outputs. Four outputs are low voltage positive emitter-coupled logic (LVPECL) at 1.2 GHz, and four are selectable as either LVDS (800 MHz) or CMOS (250 MHz) levels.

Each output has a programmable divider that can be bypassed or set to divide by any integer up to 32. The phase of one clock output relative to another clock output can be varied by means of a divider phase select function that serves as a coarse timing adjustment. Two of the LVDS/CMOS outputs feature programmable delay elements with full-scale ranges up to 8 ns of delay. This fine tuning delay block has 5-bit resolution, giving 25 possible delays from which to choose for each full-scale setting (Register 0x36 and Register 0x3A = 00000b to 11000b).

The AD9510 is ideally suited for data converter clocking applications where maximum converter performance is achieved by encode signals with subpicosecond jitter.

The AD9510 is available in a 64-lead LFCSP and can be operated from a single 3.3 V supply. An external VCO, which requires an extended voltage range, can be accommodated by connecting the charge pump supply (VCP) to 5.5 V. The temperature range is −40°C to +85°C.

Applications

• Low jitter, low phase noise clock distribution
• Clocking high speed ADCs, DACs, DDSs, DDCs, DUCs, and mixed-signal front ends (MxFEs)
• High performance wireless transceivers
• High performance instrumentation
• Broadband infrastructure

The ADCLK854 offers two selectable inputs and a sleep mode feature. The IN_SEL pin state determines which input is fanned out to all the outputs. The SLEEP pin enables a sleep mode to power down the device.

The inputs accept various types of single-ended and differential logic levels including LVPECL, LVDS, HSTL, CML, and CMOS. Table 8 provides interface options for each type of connection.

This device is available in a 48-pin LFCSP package. It is specified for operation over the standard industrial temperature range of −40°C to +85°C.

The ADM7151 is a low dropout (LDO) linear regulator that operates from 4.5 V to 16 V and provides up to 800 mA of output current. Using an advanced proprietary architecture, it provides high power supply rejection (>90 dB from 1 kHz to 1 MHz), ultralow noise (1.7 nV√Hz from 10 kHz to 1 MHz), and excellent line and load transient response with a 10 μF ceramic output capacitor. The output voltage can be set to any voltage between 1.5 V and 5.1 V with two resistors.

The ADM7151 is available in two models that optimize power dissipation and PSRR performance as a function of input and output voltage. See Table 6 and Table 7 for selection guides.

The ADM7151 regulator output noise is 1.0 μV rms from 100 Hz to 100 kHz, and the noise spectral density is 1.7 nV/√Hz from 10 kHz to 1 MHz.

The ADM7151 is available in 8-lead, 3 mm × 3 mm LFCSP and 8-lead SOIC packages, making it not only a very compact solution, but also providing excellent thermal performance for applications requiring up to 800 mA of output current in a small, low profile footprint.

ADM7151 is an adjustable V_out device. For fixed V_out version of the ADM7151, see the ADM7150.

Applications

• Regulated power noise sensitive applications
  
  • RF mixers, phase-locked loops (PLLs), voltage-controlled oscillators (VCOs), and PLLs with integrated VCOs
• Clock distribution circuits
• Ultrasound and other imaging applications
• High speed RF transceivers
• High speed, 16-bit or greater ADCs
• Communications and infrastructure
• Cable digital-to-analog converter (DAC) drivers