Datasheet AD8432 (Analog Devices)

Dual-Channel Ultralow Noise Amplifier with Selectable Gain and Input Impedance Data Sheet AD8432 FEATURES FUNCTIONAL BLOCK DIAGRAM Low noise ENB VPS1 VPS2 COMM Input voltage noise: 0.85 nV/√Hz Current noise: 2.0 pA/√Hz BIAS High speed AD8432 INH1 200 MHz bandwidth (G = 12.04 dB) OPH1 IND1 LNA1 295 V/μs slew rate OPL1 Selectable gain GMH1 G = 12.04 dB (×4) GOH1 INL1 GOL1 G = 18.06 dB (×8) GML1 G = 21.58 dB (×12) INH2 OPH2 G = 24.08 dB (×16) IND2 LNA2 Active input impedance matching OPL2 Integrated input clamp diodes GMH2 GOH2 Single-ended input, differential output INL2 GOL2
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Supply range: 4.5 V to 5.5 V GML2
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Low power: 60 mW/channel
08 Figure 1.
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 The AD8432 achieves 0.85 nV/√Hz input-referred voltage noise for amplifier with selectable gain and active impedance matching. a gain of 12.04 dB. The AD8432’s ultralow noise, low distortion, Each channel has a single-ended input, differential output, and gain accuracy, and channel-to-channel matching are ideal for integrated input clamps. By pin strapping the gain setting pins, four high performance ultrasound systems and for processing I/Q accurate gains of G = 12.04 dB, 18.06 dB, 21.58 dB, and 24.08 dB demodulator signals. (×4, ×8, ×12, and ×16, respectively) are possible. A bandwidth of The AD8432 operates on a single supply of 5 V at 24 mA. It is 200 MHz at G = 12.04 dB makes this amplifier well suited for many available in a 4 mm × 4 mm, 24-lead LFSCP. The LFCSP features high speed applications. an exposed paddle that provides a low thermal resistance path to The exceptional noise performance of the AD8432 is made the PCB, which enables more efficient heat transfer and increases possible by the active impedance matching. Using a feedback reliability. The operating temperature range is −40°C to +85°C. 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.
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Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE MAXIMUM POWER DISSIPATION ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS TEST CIRCUITS THEORY OF OPERATION LOW NOISE AMPLIFIER (LNA) GAIN SETTING TECHNIQUE ACTIVE INPUT RESISTANCE MATCHING APPLICATIONS INFORMATION TYPICAL SETUP I/Q DEMODULATION FRONT END DIFFERENTIAL-TO-SINGLE-ENDED CONVERSION EVALUATION BOARD CONNECTION AND OPERATION Power Supply Input Termination Setting the Amplifier Gain Output SCHEMATIC OUTLINE DIMENSIONS ORDERING GUIDE NOTES NOTES NOTES