AD8432

双通道超低噪声放大器，具有可选择的增益和输入阻抗 Dual-Channel Ultralow Noise Amplifier with Selectable Gain and Input Impedance

Product Details

The 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**

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CW Doppler ultrasound front ends 

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Low noise preamplification 

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Predriver for I/Q demodulators and phase shifters 

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Wideband analog-to-digital drivers

### Features and Benefits

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Low noise

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Input voltage noise: 0.85 nV/√Hz 

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Current noise: 2.0 pA/√Hz

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High speed

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200 MHz bandwidth G = 12.04 dB 

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295 V/μs slew rate 

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Selectable gain 

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G = 12.04 dB ×4

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G = 18.06 dB ×8

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G = 21.58 dB ×12 

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G = 24.08 dB ×16 

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Active input impedance matching

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Integrated input clamp diodes

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Single-ended input, differential output 

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Supply range: 4.5 V to 5.5 V 

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Low power: 60 mW/channel