Features and Benefits
- 2-Channel, 24-Bit Σ-Δ ADC
Pin Configurable (No Programmable Registers)
Pin Selectable Input Channels
Pin Programmable Input Ranges (±2.56 V or ±160 mV)
- Fixed 19.79 Hz Update Rate
- Simultaneous 50 Hz and 60 Hz Rejection
- 24-Bit No Missing Codes
Master or Slave Mode of Operation
Specified for Single 3 V and 5 V Operation
Normal: 1.3 mA @ 3 V
Power-Down: 9 µA
- See data sheet for additional features
The AD7782 is a complete 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 mV 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 kHz crystal with an on-chip PLL generating the required internal operating frequency. The output data rate from the part is fixed via the master clock at 19.79 Hz and provides simultaneous 50 Hz and 60 Hz rejection at this update rate. Eighteen-bit p-p resolution can be obtained at this update rate.
The part operates from a single 3 V or 5 V supply. When operating from 3 V supplies, the power dissipation for the part is 3.9 mW. The AD7782 is available in a 16-lead TSSOP package.
Another part in the AD778x family is the AD7783. It is similar to the AD7782 except it has two integrated current sources and only one differential input channel.
- Sensor Measurement
- Industrial Process Control
- Temperature Measurement
- Pressure Measurements
- Weigh Scales
- Portable Instrumentation
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Documentation & Resources
AN-610: The PGA on Sigma-Delta ADCs (Rev. A)2/14/2015
AN-609: Chopping on Sigma-Delta ADCs (Rev. 0)2/14/2015
AN-608: Input Buffers on Sigma-Delta ADCs (Rev. 0)2/14/2015
AN-202: An IC Amplifier User’s Guide to Decoupling, Grounding, and Making Things Go Right for a Change (Rev. B)2/14/2015
AN-968: Current Sources: Options and Circuits (Rev. 0)10/22/2008
AN-311: How to Reliably Protect CMOS Circuits Against Power Supply Overvoltaging3/8/2008
AN-607: Selecting a Low Bandwidth (<15 kSPS) Sigma-Delta ADC (Rev. E)10/12/2006
AN-615: Peak-to-Peak Resolution Versus Effective Resolution (Rev. 0)12/21/2004
AN-614: Using the AD7782 in Low Power Applications (Rev. 0)8/15/2003
AN-611: 50 Hz/60Hz Rejection on Sigma-Delta ADCs (Rev. 0)8/15/2003
AN-397: Electrically Induced Damage to Standard Linear Integrated Circuits:11/18/2002
Tools & Simulations
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
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