AD8432 Datasheet | Analog Devices

FEATURES Low noise Input voltage noise: 0.85 n V/√Hz Current noise: 2.0 p A/√Hz High speed 200 MHz bandwidth (G = 12.04 d B) 295 V/μs slew rate Selectable gain G = 12.04 d B (×4) G = 18.06 d B (×8) G = 21.58 d B (×12) G = 24.08 d B (×16) Active input impedance matching Integrated input clamp diodes Single-ended input, differential output Supply range: 4.5 V to 5.5 V Low power: 60 m W/channel APPLICATIONS CW Doppler ultrasound front ends Low noise preamplification Predriver for I/Q demodulators and phase shifters Wideband analog-to-digital drivers GENERAL DESCRIPTION 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 d B, 18.06 d B, 21.58 d B, and 24.08 d B (×4, ×8, ×12, and ×16, respectively) are possible. A bandwidth of 200 MHz at G = 12.04 d B 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 promising 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. FUNCTIONAL BLOCK DIAGRAM VPS1 VPS2 M INH1 IND1 INL1 INH2 IND2 INL2 BIAS LNA1 LNA2 OPH1 OPL1 GMH1 GOH1 GOL1 GML1 OPH2 OPL2 GMH2 GOH2 GOL2 GML2 Figure 1. 08341-001 The AD8432 achieves 0.85 n V/√Hz input-referred voltage noise for a gain of 12.04 d B. 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 m A. It is available in a 4 mm × 4 mm,...