Datasheet AD7782 (Analog Devices)

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Read Only, Pin Configured 24-Bit
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ADC AD7782 FEATURES FUNCTIONAL BLOCK DIAGRAM 2-Channel, 24-Bit
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ADC Pin Configurable (No Programmable Registers) VDD GND REFIN(+) REFIN(–) XTAL1 XTAL2 Pin Selectable Input Channels Pin Programmable Input Ranges (
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2.56 V or
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160 mV) OSCILLATOR Fixed 19.79 Hz Update Rate AD7782 AND PLL Simultaneous 50 Hz and 60 Hz Rejection 24-Bit No Missing Codes 18.5-Bit p-p Resolution (
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2.56 V Range) AIN1(+) SERIAL DOUT/RDY INTERFACE 16.5-Bit p-p Resolution (
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160 mV Range) AIN1(–) 24-BIT
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MUX BUF PGA AND ADC SCLK AIN2(+) CONTROL INTERFACE LOGIC MODE AIN2(–) Master or Slave Mode of Operation Slave Mode CS 3-Wire Serial SPI™, QSPI™, MICROWIRE™, and DSP-Compatible CH1 Schmitt Trigger on SCLK /CH2 RANGE POWER Specified for Single 3 V and 5 V Operation BASIC CONNECTION DIAGRAM Normal: 1.3 mA @ 3 V Power-Down: 9
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A POWER SUPPLY ON-CHIP FUNCTIONS VDD Rail-Rail Input Buffer and PGA AD7782 ANALOG AIN1(+) APPLICATIONS CS INPUT AIN1(–) Sensor Measurement DIGITAL DOUT/RDY INTERFACE Industrial Process Control ANALOG AIN2(+) SCLK INPUT AIN2(–) Temperature Measurement XTAL1 32.768kHz Pressure Measurements REFERENCE REFIN(+) CRYSTAL INPUT REFIN(–) XTAL2 Weigh Scales Portable Instrumentation GND GENERAL DESCRIPTION
The device operates from a 32.768 kHz crystal with an on-chip PLL The AD7782 is a complete analog front end for low-frequency generating the required internal operating frequency. The output measurement applications. The 24-bit sigma-delta ADC contains data rate from the part is fixed via the master clock at 19.79 Hz and two fully differential analog input channels that can be config- provides simultaneous 50 Hz and 60 Hz rejection at this update ured with a gain of 1 or 16 allowing full-scale input signal ranges rate. Eighteen-bit p-p resolution can be obtained at this update rate. of ± 2.56 V or ± 160 mV from a +2.5 V differential reference The part operates from a single 3 V or 5 V supply. When operating input. from 3 V supplies, the power dissipation for the part is 3.9 mW. The AD7782 has an extremely simple, read-only digital interface The AD7782 is available in a 16-lead TSSOP package. which can be operated in master mode or slave mode. There are Another part in the AD778x family is the AD7783. It is similar no on-chip registers to be programmed. The input signal range to the AD7782 except it has two integrated current sources and and input channel selection are configured using two external pins. only one differential input channel. SPI and QSPI are trademarks of Motorola Inc. MICROWIRE is a trademark of National Semiconductor Corporation. REV. A 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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2012