Datasheet AD7724 (Analog Devices)

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Dual CMOS
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Modulators AD7724 FEATURES FUNCTIONAL BLOCK DIAGRAM 13 MHz Master Clock Frequency 0 V to +2.5 V or
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1.25 V Input Range REF1 REF2A REF2B Single Bit Output Stream 2.5V 90 dB Dynamic Range REFERENCE Power Supplies AD7724 AVDD, DVDD: 5 V
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5% DVDD1: 3 V
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5% AVIN(+)
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ADATA Logic Outputs 3 V/5 V Compatible AVIN(–) MODULATOR A On-Chip 2.5 V Voltage Reference SCLK 48-Lead LQFP BVIN(+)
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BDATA BVIN(–) MODULATOR B XTAL OFF XTAL1 CLOCK MZERO CIRCUITRY XTAL2/MCLK GC BIP CONTROL DVAL LOGIC STBY RESET DVDD DVDD1 DGND AVDD AGND GENERAL DESCRIPTION
This device consists of two seventh order sigma-delta modula- tors. Each modulator converts its analog input signal into a high speed 1-bit data stream. The part operates from a 5 V power supply and accepts a differential input range of 0 V to +2.5 V or ±1.25 V centered about a common-mode bias. The analog inputs are continuously sampled by the analog modulators, eliminating the need for external sample-and-hold circuitry. The input information is contained in the output stream as a density of ones. The original information can be digitally reconstructed with an appropriate digital filter. The part provides an accurate on-chip 2.5 V reference for each modulator. A reference input/output function is provided to allow either the internal reference or an external system refer- ence to be used as the reference source for the modulator. The device is offered in a 48-lead LQFP package and designed to operate from –40°C to +85°C. REV. B Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that
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