AD7713 CMOS, Low Power 24-Bit Sigma-Delta, Signal Conditioning ADC with Matched RTD Current Sources

The AD7713 is a complete analog front end for low frequency measurement applications. The device accepts low level signals directly from a transducer or high level signals (4 × VREF ) and outputs a serial digital word. It employs a sigma-delta conversion technique to realize up to 24 bits of no missing codes performance. The input signal is applied to a proprietary programmable gain front end based around an analog modulator. The modulator output is processed by an on-chip digital filter. The first notch of this digital filter can be programmed via the on-chip control register allowing adjustment of the filter cutoff and settling time.

The part features two differential analog inputs and one single-ended high level analog input as well as a differential reference input. It can be operated from a single supply (AVDD and DVDD at +5 V). The part provides two current sources which can be used to provide excitation in three-wire and four-wire RTD configurations. The AD7713 thus performs all signal conditioning and conversion for a single, dual or three-channel system.

The AD7713 is ideal for use in smart, microcontroller-based systems. Gain settings, signal polarity and RTD current control can be configured in software using the bidirectional serial port. The AD7713 contains self-calibration, system calibration and background calibration options and also allows the user to read and to write the on-chip calibration registers.

CMOS construction ensures low power dissipation and a hardware programmable power-down mode reduces the standby power consumption to only 150 µW typical. The part is available in a 24-pin, 0.3 inch wide, plastic and hermetic dual-in-line package (DIP) as well as a 24-lead small outline (SOIC) package.

Features and Benefits

Charge Balancing ADC
24 Bits No Missing Codes
±0.0015% Nonlinearity
Low-Pass Filter with Programmable Filter Cutoffs
Ability to Read/Write Calibration Coefficients
Bidirectional Microcontroller Serial Interface

3-Channel Programmable Gain Front End
Gains from 1 to 128
2 Differential Inputs
1 Single-Ended High Voltage Input
Single-Supply Operation
Low Power (3.5 mW typ) with Power-Down Mode (150 µW typ)

Analog to Digital Converters

A/D Converters

Data Sheets

Document	note
AD7713: LC2MOS, Loop-Powered Signal Conditioning ADC Data Sheet (Rev. D)	PDF 362 kB

Application Notes

Document	note
AN-202: An IC Amplifier User’s Guide to Decoupling, Grounding, and Making Things Go Right for a Change (Rev. B)	PDF 76.97 K
AN-389: Using Sigma-Delta Converters-Part 2	PDF 590 kB
AN-388: Using Sigma-Delta Converters-Part 1	PDF 590 kB
AN-348: Avoiding Passive-Component Pitfalls	PDF 931 kB
AN-311: How to Reliably Protect CMOS Circuits Against Power Supply Overvoltaging	PDF 217 kB
AN-607: Selecting a Low Bandwidth (<15 kSPS) Sigma-Delta ADC (Rev. E)	PDF 222 kB
AN-615: Peak-to-Peak Resolution Versus Effective Resolution (Rev. 0)	PDF 70 kB
AN-397: Electrically Induced Damage to Standard Linear Integrated Circuits:	PDF 149 kB
AN-283: Sigma-Delta ADCs and DACs	PDF 1699 kB
AN-553: Adjusting the Calibration Coefficients on the AD771X Family of ADCs	PDF 221 kB
AN-406: Using the AD771X Family of 24-Bit Sigma-Delta A/D Converters	PDF 187 kB

Order Information

Part Number	Package	Packing Qty	Temp Range	Price 100-499	Price 1000+	RoHS
AD7713ANZ Production	24 ld PDIP	OTH 15	-40 to 85C	34.19	26.1	Y
AD7713ARZ Production	24 ld SOIC - Wide	OTH 31	-40 to 85C	32.64	24.91	Y
AD7713ARZ-REEL Production	24 ld SOIC - Wide	REEL 1000	-40 to 85C	0	24.91	Y