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.
Applications
- CW Doppler ultrasound front ends
- Low noise preamplification
- Predriver for I/Q demodulators and phase shifters
- Wideband analog-to-digital drivers
