Dual-Channel Ultralow Noise Amplifier with Selectable Gain and Input Impedance
The AD8432 is a dual-channel, low power, ultralow noise amplifier with selectable gain and active impedance matching. Each channel has a single-ended input, differential output, and integrated input clamps. By pin strapping the gain setting pins, four accurate gains of G = 12.04 dB, 18.06 dB, 21.58 dB, and 24.08 dB (×4, ×8, ×12, and ×16, respectively) are possible. A bandwidth of 200 MHz at G = 12.04 dB makes this amplifier well suited for many high speed applications.
The exceptional noise performance of the AD8432 is made possible by the active impedance matching. Using a feedback network, the input impedance of the amplifiers can be adjusted to match the signal source impedance without compromising the noise performance. Impedance matching and low noise in the AD8432 allow designers to create wider dynamic range systems that are able to detect even very low level signals.
The AD8432 achieves 0.85 nV/√Hz input-referred voltage noise for a gain of 12.04 dB. The AD8432’s ultralow noise, low distortion, gain accuracy, and channel-to-channel matching are ideal for high performance ultrasound systems and for processing I/Q demodulator signals.
The AD8432 operates on a single supply of 5 V at 24 mA. It is available in a 4 mm × 4 mm, 24-lead LFSCP. The LFCSP features an exposed paddle that provides a low thermal resistance path to the PCB, which enables more efficient heat transfer and increases reliability. The operating temperature range is −40°C to +85°C.
- CW Doppler ultrasound front ends
- Low noise preamplification
- Predriver for I/Q demodulators and phase shifters
- Wideband analog-to-digital drivers
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
The board provides access to the inputs, the outputs, and the gain settings. As shipped, the board is configured for a gain of 21 dB and 50 Ω input termination. Multiple combinations of gain and impedance matching are available to the user.
See figure 79 for bench Setup and testing the AD8432-EVALZ. The AD8432 data sheet available on-line. See the Evaluation Board Section for additional details.
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.