500毫安的CMOS模数转换器AD7714信号的清理

　　The AD7714 is a complete analog front end for low-frequency measurement applications. The device accepts low level signals directly from a transducer and outputs a serial digital word. It employs a sigma-delta conversion technique to realize up to 24 bits of no missing codes performance. The input signal is applied to a proprietary programmable gain front end based around an analog modulator. The modulator output is processed by an onchip digital filter. The first notch of this digital filter can be programmed via the on-chip control register allowing adjustment of the filter cutoff and settling time. The part features three differential analog inputs （which can also be configured as five pseudo-differential analog inputs） as well as a differential reference input. It operates from a single supply （+3␣ V or +5␣ V）。 The AD7714 thus performs all signal conditioning and conversion for a system consisting of up to five channels. The AD7714 is ideal for use in smart， microcontroller- or DSPbased systems. It features a serial interface that can be configuredfor three-wire operation. Gain settings， signal polarity and channel selection can be configured in software using the serial port. The AD7714 provides self-calibration， system calibration and background calibration options and also allows the user to read and write the on-chip calibration registers. CMOS construction ensures very low power dissipation， and the power-down mode reduces the standby power consumption to 15␣ µW typ. The part is available in a 24-pin， 0.3 inch-wide， plastic dual-in-line package （DIP）; a 24-lead small outline （SOIC） package， a 28-lead shrink small outline package （SSOP） and a 24-lead thin shrink small outline package （TSSOP）.