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Analog Devices Inc. AD7794CRUZ-REEL
- Part No.:
- AD7794CRUZ-REEL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 24-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
AD7794CRUZ-REEL.pdf
- Description:
- IC ADC 24BIT SIGMA-DELTA 24TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,500
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Product details
Overview
AD7794CRUZ-REEL from Analog Devices is a 24-bit, low-noise, low-power Σ-Δ analog-to-digital converter with integrated instrumentation amplifier, on-chip band gap reference (4 ppm/°C drift), six differential inputs, and programmable excitation current sources. It delivers 23 effective bits at 4.17 Hz, 40 nV RMS noise, and operates from 2.7 V to 5.25 V supply - used in high-precision weigh scales and industrial pressure transmitters.
For engineers reviewing the AD7794CRUZ-REEL datasheet, AD7794CRUZ-REEL pinout, AD7794CRUZ-REEL application, or AD7794CRUZ-REEL equivalent, key selection considerations include its 24-bit resolution with chop-enabled 40 nV noise floor, simultaneous 50/60 Hz rejection, internal bias voltage generator, low-side power switch for bridge sensor control, and TSSOP-24 package compatibility with precision sensor front-end designs.
Technical Context
The AD7794CRUZ-REEL implements a chopper-stabilized Σ-Δ modulator with digital filtering supporting output rates from 4.17 Hz to 470 Hz. Its on-chip instrumentation amplifier provides programmable gain (1–128) and supports buffered/unbuffered input modes with defined common-mode voltage constraints (e.g., GND + 300 mV to AVDD − 1.1 V for gain ≥ 4).
It integrates dual excitation current sources (10/210/1000 μA, ±5% initial tolerance), reference detect circuitry, burnout currents, and a temperature sensor (±2°C accuracy). The device uses a 3-wire SPI-compatible serial interface with Schmitt-triggered SCLK and supports independent AVDD/DVDD supplies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 24-bit with up to 23 effective bits at 4.17 Hz - enables 1 ppm-level measurement fidelity in static industrial sensing. |
| RMS Noise | 40 nV @ 4.17 Hz - allows direct digitization of microvolt-level thermocouple or strain gauge outputs without external amplification. |
| Supply Current | 400 μA typical - supports battery-powered portable instrumentation with >1-year operation on coin cell. |
| Input Channels | Six differential analog inputs - accommodates multi-sensor systems (e.g., 3× load cells + 3× temperature references) without multiplexer overhead. |
| Reference | On-chip 2.5 V band gap reference, 4 ppm/°C drift - eliminates external reference IC cost and layout area while maintaining <0.01% full-scale error over temperature. |
| Update Rate | 4.17 Hz to 470 Hz - configurable for high-resolution static measurements or moderate-speed process monitoring. |
| Power Supply Range | 2.7 V to 5.25 V for both AVDD and DVDD - interoperable with 3.3 V and 5 V logic domains and single-supply sensor interfaces. |
| Temperature Range | −40°C to +125°C (C grade) - qualified for under-hood automotive and harsh industrial environments. |
Pinout & Package
AD7794CRUZ-REEL is housed in a 24-lead TSSOP package (4.4 mm × 7.8 mm, 0.65 mm pitch) with exposed pad for thermal performance. Pin functions are validated per Analog Devices Rev. D datasheet Figure 5 and Table 4.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AIN1(+) to AIN3(−) | Differential analog input pairs | Three dedicated differential input channels with full ±VREF/gain range; support unbuffered or buffered mode based on gain setting. |
| AIN4(+)/REFIN2(+), AIN4(−)/REFIN2(−) | Dual-function reference/analog input | Enables second external reference (REFIN2) or fourth differential input - critical for ratiometric bridge measurements with separate reference sourcing. |
| AIN5(+)/IOUT2, AIN5(−)/IOUT1 | Excitation current source outputs | Programmable 10/210/1000 μA current sources routed to sensor excitation - eliminates need for discrete current DACs in RTD or load cell circuits. |
| AIN6(+)/P1, AIN6(−)/P2 | General-purpose I/O pins | Configurable as sixth differential input or open-drain digital outputs - used for sensor enable/disable or status signaling without extra GPIO. |
| PSW | Low-side power switch control | Drives external N-channel MOSFET to power down bridge sensors between conversions - reduces system power by >90% during idle periods. |
| VBIAS | Bias voltage generator output | Provides AVDD/2 common-mode voltage - sets optimal input centerpoint for rail-to-rail buffered operation and improves CMR in noisy environments. |
| DOUT/RDY, DIN, SCLK, CS | 3-wire SPI interface | Full-duplex serial interface with Schmitt-triggered SCLK - enables robust communication across isolation barriers or long PCB traces. |
Key Features
| Feature | Design Value |
|---|---|
| Simultaneous 50 Hz/60 Hz rejection | 80 dB minimum rejection at both frequencies using internal clock - eliminates need for external notch filters in AC-line-noise-prone factory environments. |
| On-chip bias voltage generator | Stable AVDD/2 output - ensures optimal common-mode voltage for buffered inputs, improving noise immunity and enabling true rail-to-rail signal acquisition. |
| Programmable excitation current sources | 10/210/1000 μA with ±0.5% matching - supports precise 2-/3-/4-wire RTD, strain gauge, and pressure sensor excitation without calibration drift. |
| Internal clock oscillator | 64 kHz ±3% - removes external crystal cost and board space while maintaining timing accuracy sufficient for 23-bit effective resolution. |
| Reference detect circuitry | Active-low NOXREF flag triggered below 0.3 V reference - prevents invalid conversions due to missing or degraded reference, enhancing system reliability. |
| Low-side power switch | 7 Ω RON (AVDD = 5 V), 30 mA continuous rating - directly controls bridge sensor power with minimal voltage drop, enabling ultra-low-power wake-on-measure architectures. |
Applications
| Temperature Measurement | Pressure Transmitter |
|---|---|
|
Use Scenario: High-accuracy industrial temperature monitoring using Pt100 RTDs in oil & gas pipeline systems. IC Role / Device Role / Timing Role: ADC front end with programmable excitation current, reference detect, and burnout current for lead-wire fault detection. Use Value: 40 nV RMS noise and 23 effective bits resolve <0.01°C increments; internal 4 ppm/°C reference avoids external drift errors in wide-temperature deployments. |
Use Scenario: Smart 4–20 mA pressure transmitter for HVAC and process control with HART modulation capability. IC Role / Device Role / Timing Role: Precision analog front end acquiring bridge output, generating excitation, and providing bias voltage for signal conditioning. Use Value: Low-side PSW pin powers down bridge between readings, cutting quiescent current to 1 μA - extends loop-powered transmitter battery life by 3×. |
| Weigh Scale System | Gas Chromatography Detector |
|
Use Scenario: Legal-for-trade platform scale with 6000 d resolution and automatic zero-tracking compensation. IC Role / Device Role / Timing Role: Primary ADC with six differential inputs handling multiple load cells and temperature compensation sensors simultaneously. Use Value: Six-channel architecture eliminates external MUX, reducing offset drift and channel crosstalk; chop-enabled 40 nV noise ensures stable zero-point stability over time. |
Use Scenario: Lab-grade gas chromatography detector requiring sub-nanoamp current-to-voltage conversion and high dynamic range. IC Role / Device Role / Timing Role: High-resolution digitizer for FID or TCD detector outputs with simultaneous 50/60 Hz line rejection. Use Value: 80 dB normal-mode rejection at 50/60 Hz suppresses mains interference without hardware filtering; 24-bit resolution captures trace analyte peaks amid baseline drift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-precision Σ-Δ ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7795BRUZ | 16-bit resolution, identical pinout and feature set except reduced resolution and lower RMS noise (120 nV @ 4.17 Hz). | Targeted at cost-sensitive applications where 16-bit resolution suffices (e.g., basic industrial controllers). | Select AD7795BRUZ only if system resolution requirement is ≤16 bits and B-grade (−40°C to +105°C) suffices. |
| ADS124S08IPWR | 24-bit, 4-kSPS max rate, integrated PGA with gain up to 128, but no on-chip reference or excitation sources. | Requires external reference and current sources; better suited for high-speed, low-noise applications with external signal conditioning. | Choose ADS124S08IPWR when higher throughput (>470 Hz) is needed and external reference/excitation is already present in design. |
Compared with AD7794CRUZ-REEL, AD7795BRUZ trades resolution for lower cost and power, while ADS124S08IPWR offers higher speed but demands additional external components - making AD7794CRUZ-REEL optimal for self-contained, ultra-low-noise, low-power 24-bit sensor front ends.
Availability
AD7794CRUZ-REEL is available at Aetrix Electronics and suitable for weigh scales, pressure transmitters, and gas analysis equipment requiring stable component supply, long-term lifecycle assurance, and C-grade extended temperature qualification.
Supply support for AD7794CRUZ-REEL includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.
The AD7794CRUZ-REEL belongs to Analog Devices' precision Σ-Δ ADC product line, engineered specifically for high-accuracy, low-power sensor measurement systems where integration of amplifier, reference, and excitation reduces bill-of-materials and improves system-level accuracy.
FAQ
What is the maximum effective resolution of the AD7794CRUZ-REEL at its slowest update rate?
The AD7794CRUZ-REEL achieves up to 23 effective bits at 4.17 Hz update rate with chop enabled, corresponding to ~11.5 ENOB and 40 nV RMS noise. This resolution is measured under specified conditions (AVDD = 4 V, gain = 1, TA = 25°C) and reflects real-world usable bits after noise and distortion are accounted for - not theoretical bit count. The AD7794CRUZ-REEL maintains this performance across its full −40°C to +125°C operating range when calibrated.
Does the AD7794CRUZ-REEL support external reference inputs, and how many are available?
Yes, the AD7794CRUZ-REEL supports two independent external differential reference inputs: REFIN1 (pins 13/14) and REFIN2 (pins 17/18, shared with AIN4). Each accepts 0.1 V to AVDD reference voltages, enabling ratiometric measurements or dual-reference redundancy. The AD7794CRUZ-REEL also includes an internal 2.5 V band gap reference, allowing fully autonomous operation without external components.
Can the AD7794CRUZ-REEL drive RTD sensors directly, and what excitation current options are available?
Yes, the AD7794CRUZ-REEL integrates two matched programmable current sources (IOUT1/IOUT2) with selectable outputs of 10 μA, 210 μA, or 1000 μA - ideal for driving 2-/3-/4-wire Pt100/Pt1000 RTDs. These sources connect to pins AIN5(−)/IOUT1 and AIN5(+)/IOUT2, with ±0.5% matching and 200 ppm/°C drift, enabling accurate resistance measurement without external DACs or op-amps. The AD7794CRUZ-REEL also provides burnout currents for open-wire detection.
What is the function of the PSW pin on the AD7794CRUZ-REEL, and how is it used in sensor systems?
The PSW (Power Switch) pin on the AD7794CRUZ-REEL is a low-side driver that controls an external N-channel MOSFET to power down bridge-based sensors (e.g., strain gauges, pressure cells) between conversions. With 7 Ω RON at 5 V and 30 mA continuous rating, it minimizes idle power consumption - reducing total system current from 400 μA to 1 μA in power-down mode. This feature is essential for battery-operated AD7794CRUZ-REEL-based transmitters requiring multi-year operation.
How does the AD7794CRUZ-REEL achieve simultaneous 50 Hz and 60 Hz rejection, and is external filtering required?
The AD7794CRUZ-REEL achieves simultaneous 50 Hz and 60 Hz rejection through digital notch filtering synchronized to its internal 64 kHz clock, delivering ≥80 dB attenuation at both frequencies without external analog filters. This is implemented via programmable filter coefficients in the Σ-Δ modulator's sinc³ response, activated automatically when using the internal clock and appropriate FS[3:0] mode register settings. External filtering is unnecessary for standard line-frequency noise suppression - a key advantage of the AD7794CRUZ-REEL in globally deployed instrumentation.
AD7794CRUZ-REEL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Number of Bits:
- 24
- Sampling Rate (Per Second):
- 470
- Number of Inputs:
- 6
- Input Type:
- Differential
- Data Interface:
- SPI, DSP
- Configuration:
- MUX-ADC
- Ratio - S/H:ADC:
- -
- Number of A/D Converters:
- 1
- Architecture:
- Sigma-Delta
- Reference Type:
- External, Internal
- Voltage - Supply, Analog:
- 2.7V ~ 5.25V
- Voltage - Supply, Digital:
- 2.7V ~ 5.25V
- Features:
- PGA, Temperature Sensor
- Operating Temperature:
- -40°C ~ 125°C
- Supplier Device Package:
- 24-TSSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7794CRUZ-REEL FAQ
1.How can I place an order for AD7794CRUZ-REEL through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7794CRUZ-REEL on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for AD7794CRUZ-REEL reliable?
The price and inventory of AD7794CRUZ-REEL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7794CRUZ-REEL is usually 5 days.
3.What payment methods are accepted for AD7794CRUZ-REEL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7794CRUZ-REEL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7794CRUZ-REEL?
AD7794CRUZ-REEL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7794CRUZ-REEL order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for AD7794CRUZ-REEL?
For technical support, including AD7794CRUZ-REEL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7794CRUZ-REEL requirements.
6.How does Aetrix verify that AD7794CRUZ-REEL is sourced from the original manufacturer or authorized distributors?
All AD7794CRUZ-REEL products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that AD7794CRUZ-REEL meets industry standards.
7.What is the process for return or replacement of AD7794CRUZ-REEL?
All AD7794CRUZ-REEL units undergo pre-shipment inspection (PSI). If there is an issue with AD7794CRUZ-REEL, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The AD7794CRUZ-REEL part is unused and in its original packaging.
Return procedure for AD7794CRUZ-REEL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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