AD7782 Datasheet | Analog Devices

a Features 2-Channel, 24-Bit ⌺- ⌬ ADC Pin Configurable (No Programmable Registers) Pin Selectable Input Channels Pin Programmable Input Ranges (؎2.56 V or ؎160 m V) Fixed 19.79 Hz Update Rate Simultaneous 50 Hz and 60 Hz Rejection 24-Bit No Missing Codes 18.5-Bit p-p Resolution (؎2.56 V Range) 16.5-Bit p-p Resolution (؎160 m V Range) INTERFACE Master or Slave Mode of Operation Slave Mode 3-Wire Serial SPI™, QSPI™, MICROWIRE™, and DSP-patible Schmitt Trigger on SCLK POWER Specified for Single 3 V and 5 V Operation Normal: 1.3 m A @ 3 V Power-Down: 9 ␮ A ON-CHIP FUNCTIONS Rail-Rail Input Buffer and PGA APPLICATIONS Sensor Measurement Industrial Process Control Temperature Measurement Pressure Measurements Weigh Scales Portable Instrumentation Read Only, Pin Configured 24-Bit ⌺-⌬ ADC AD7782 FUNCTIONAL BLOCK DIAGRAM VDD GND REFIN(+) REFIN(- ) XTAL1 XTAL2 OSCILLATOR AND PLL AIN1(+) AIN1(- ) AIN2(+) AIN2(- ) MUX BUF PGA 24-BIT ⌺-⌬ ADC SERIAL INTERFACE AND CONTROL LOGIC DOUT/RDY SCLK MODE CH1/CH2 RANGE BASIC CONNECTION DIAGRAM POWER SUPPLY VDD ANALOG INPUT ANALOG INPUT REFERENCE INPUT AIN1(+) AIN1(- ) AIN2(+) AIN2(- ) REFIN(+) REFIN(- ) GND CS DOUT/RDY SCLK XTAL1 XTAL2 32.768k Hz CRYSTAL DIGITAL INTERFACE GENERAL DESCRIPTION The AD7782 is a plete analog front end for low-frequency measurement applications. The 24-bit sigma-delta ADC contains two fully differential analog input channels that can be configured with a gain of 1 or 16 allowing full-scale input signal ranges of ± 2.56 V or ± 160 m V from a +2.5 V differential reference input. The AD7782 has an extremely simple, read-only digital interface which can be operated in master mode or slave mode. There are no on-chip registers to be programmed. The input signal range and input channel selection are configured using two external pins. The device operates from a 32.768 k Hz crystal with an on-chip PLL generating the required internal operating frequency. The output data rate from the part is...