AD7794 Series

6-Channel, Low Noise, Low Power, 24-Bit Sigma Delta ADC with On-Chip In-Amp and Reference

Catalog

6-Channel, Low Noise, Low Power, 24-Bit Sigma Delta ADC with On-Chip In-Amp and Reference

Part	Operating Temperature [Min]	Operating Temperature [Max]	Data Interface	Reference Type	Input Type	Architecture	Package / Case	Package / Case	Supplier Device Package	Features	Voltage - Supply, Digital [Max]	Voltage - Supply, Digital [Min]	Mounting Type	Sampling Rate (Per Second)	Voltage - Supply, Analog [Min]	Voltage - Supply, Analog [Max]	Configuration	Number of Bits	Number of A/D Converters	Number of Inputs	Input Range	Supplied Contents	Utilized IC / Part	Power (Typ) @ Conditions
Analog Devices AD7794BRUZ-REEL	-40 °C	105 ░C	DSP SPI	External Internal	Differential	Sigma-Delta	24-TSSOP	0.173 in 4.4 mm	24-TSSOP	PGA Temperature Sensor	5.25 V	2.7 V	Surface Mount	470 Per Second	2.7 V	5.25 V	MUX-ADC	24	1	6
Analog Devices AD7794BRU-REEL	-40 °C	105 ░C	DSP SPI	External Internal	Differential	Sigma-Delta	24-TSSOP	0.173 in 4.4 mm	24-TSSOP	PGA Temperature Sensor	5.25 V	2.7 V	Surface Mount	470 Per Second	2.7 V	5.25 V	MUX-ADC	24	1	6
Analog Devices EVAL-AD7794EBZ			DSP SPI											470 Per Second				24	1		±VREF/gain	Board(s) Cable(s)	AD7794	2.5 mW
Analog Devices AD7794BRUZ	-40 °C	105 ░C	DSP SPI	External Internal	Differential	Sigma-Delta	24-TSSOP	0.173 in 4.4 mm	24-TSSOP	PGA Temperature Sensor	5.25 V	2.7 V	Surface Mount	470 Per Second	2.7 V	5.25 V	MUX-ADC	24	1	6

Catalog

6-Channel, Low Noise, Low Power, 24-Bit Sigma Delta ADC with On-Chip In-Amp and Reference

Key Features

• Up to 23 effective bits

• RMS noise: 40 nV @ 4.17 Hz, 85 nV @ 16.7 Hz

• Current: 400 μA typical

• Power-down: 1 μA maximum

• Low noise, programmable gain, instrumentation amp

• Band gap reference with 4 ppm/°C drift typical

• Update rate: 4.17 Hz to 470 Hz

• Six differential analog inputs

• Internal clock oscillator

• Simultaneous 50 Hz/60 Hz rejection

• Reference detect

• Programmable current sources

Description

The AD7794/AD7795are low power, low noise, complete analog front ends for high precision measurement applications. They contain a low noise, 24-/16-bit Σ-Δ ADC with six differential inputs. The on-chip low noise instrumentation amplifier means that signals of small amplitude can be interfaced directly to the ADC.Each device contains a precision, low noise, low drift internal band gap reference, and can also accept up to two external differential references. Other on-chip features include programmable excitation current sources, burnout currents, and a bias voltage generator that is used to set the common-mode voltage of a channel to AVDD/2. The low-side power switch can be used to power down bridge sensors between conversions, minimizing the system’s power consumption. The AD7794/AD7795 can operate with either an internal clock or an external clock. The output data rate from each part can vary from 4.17 Hz to 470 Hz.Both parts operate with a power supply from 2.7 V to 5.25 V. The B-grade parts (AD7794 and AD7795) are specified for a temperature range of −40°C to +105°C while the C-grade part (AD7794) is specified for a temperature range of −40°C to +125°C. They consume a current of 400 μA typical and are housed in a 24-lead TSSOP.ApplicationsTemperature measurementPressure measurementWeigh scalesStrain gage transducersGas analysis