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Analog Devices Inc. AD7701AN
- Part No.:
- AD7701AN
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
AD7701AN.pdf
- Description:
- IC ADC 16BIT SIGMA-DELTA 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,499
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Product details
Overview
AD7701AN from Analog Devices is a monolithic 16-bit sigma-delta analog-to-digital converter with on-chip 6-pole Gaussian digital filtering, self-calibration circuitry, and flexible serial interface. It delivers 0.003% max integral nonlinearity, 4 kSPS output data rate, and 0 V to +2.5 V or ±2.5 V analog input range. It is used in high-accuracy, low-frequency measurement systems such as industrial weigh scales and remote data acquisition nodes.
For engineers reviewing the AD7701AN datasheet, AD7701AN pinout, AD7701AN application, or AD7701AN equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternative parts with documented differences, and supply support for long-lifecycle embedded instrumentation designs.
Technical Context
The AD7701AN employs a second-order sigma-delta modulator with charge-balancing architecture and an on-chip six-pole Gaussian digital filter that achieves 55 dB rejection at 60 Hz when configured for 10 Hz corner frequency. Its master clock (CLKIN) directly determines sampling rate (fCLKIN/256), output update rate (fCLKIN/1024), and filter cutoff (fCLKIN/409,600).
It supports three serial interface modes-Asynchronous Communications (AC), Synchronous External Clocking (SEC), and Synchronous Self-Clocking (SSC)-selected via the MODE pin, enabling direct connection to UARTs or microcontroller SPI peripherals. Calibration is initiated by pulsing CAL high for >4 cycles, and system-level offset/gain correction is supported via SC1/SC2 configuration during calibration.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 16-bit binary output with guaranteed no missing codes - ensures full dynamic range usability without gain staging. |
| Integral Nonlinearity | ±0.003% FSR max - enables accurate end-point measurement in precision weighing and process control transducers. |
| Output Data Rate | Up to 4 kSPS - supports real-time monitoring of slow-varying physical signals (e.g., temperature, pressure, strain) without oversampling burden. |
| Analog Input Range | 0 V to +2.5 V (unipolar) or ±2.5 V (bipolar) - matches standard reference voltages and simplifies front-end signal conditioning. |
| Power Dissipation | 25 mW typical in normal operation; 10 µW in SLEEP mode - suitable for loop-powered or battery-operated field instruments. |
| Digital Filter Type | 6-pole Gaussian response - provides 55 dB 60 Hz rejection at 10 Hz cutoff, eliminating need for external notch filters in AC-line-noise environments. |
| Self-Calibration | On-chip zero/full-scale calibration with SRAM storage - removes drift-induced errors over temperature without host MCU intervention. |
Pinout & Package
AD7701AN is supplied in a 20-pin plastic DIP (N-20) package with 0.3-inch body width and through-hole mounting. Pin spacing is 0.1 inch; lead finish is matte tin.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| MODE (Pin 1) | Serial interface mode select | Configures SCLK as input/output and defines data framing: –5 V = AC mode (UART-compatible), DGND = SEC mode (SPI-like), +5 V = SSC mode (self-clocked). |
| AIN (Pin 9) | Analog input | High-impedance (1 nA bias), rail-to-rail-capable input accepting unipolar (0–2.5 V) or bipolar (±2.5 V) signals referenced to AGND. |
| VREF (Pin 10) | Voltage reference input | 2.5 V nominal reference setting full-scale value; determines both unipolar span and bipolar magnitude; supports system calibration headroom up to ±0.1 V. |
| BP/UP (Pin 12) | Bipolar/unipolar mode control | Logic low selects 0 V to VREF unipolar range; logic high selects ±VREF bipolar range - configures internal gain and code mapping. |
| CAL (Pin 13) | Calibration trigger | Pulse high (>4 CLKIN cycles) to reset and initiate on-chip zero/full-scale calibration; also serves as synchronization strobe for multi-device systems. |
| SLEEP (Pin 11) | Low-power mode enable | Logic low halts internal clocking and reduces power to 10 µW; wake-up requires CLKIN restart and recalibration if timing-critical. |
| DRDY (Pin 18) | Data ready indicator | Active-low open-drain output signaling valid data in output register; pulses high for 4 CLKIN cycles during register reload - critical for synchronous read timing. |
| SDATA (Pin 20) | Serial data output | 16-bit MSB-first serial word output; format and timing depend on MODE setting; transitions synchronized to SCLK falling edge in SEC/SSC modes. |
Key Features
| Feature | Design Value |
|---|---|
| On-chip 6-pole Gaussian digital filter | Provides fixed 55 dB 60 Hz rejection at 10 Hz bandwidth - eliminates need for external analog anti-aliasing or line-frequency notch filters. |
| Programmable filter corner frequency | Set via CLKIN (fCLKIN/409,600); ranges from 0.1 Hz to 10 Hz - enables optimization for ultra-low-noise DC measurements or faster step-response applications. |
| System calibration support | SC1/SC2 pins allow inclusion of external sensor/PGA offsets and gains in calibration loop - removes total system error, not just ADC error. |
| Ultralow standby power | 10 µW typical in SLEEP mode with CLKIN stopped - extends battery life in portable instrumentation and enables energy harvesting compatibility. |
| No missing codes guarantee | ±0.5 LSB DNL max ensures monotonicity across full 16-bit range - avoids data ambiguity in closed-loop control or safety-critical threshold detection. |
Applications
| Industrial Weigh Scales | Remote Data Acquisition |
|---|---|
|
Use Scenario: High-resolution weight measurement in platform scales, hopper load cells, and tank level sensors operating in noisy factory environments. IC Role / Device Role / Timing Role: Primary A/D converter digitizing millivolt-level bridge outputs; performs on-chip filtering and self-calibration to maintain accuracy across temperature swings. Use Value: Eliminates external op-amp gain stages and 60 Hz notch filters due to integrated 55 dB line-rejection and 16-bit no-missing-codes resolution. |
Use Scenario: Battery-powered environmental sensor nodes measuring temperature, humidity, and gas concentration in distributed field deployments. IC Role / Device Role / Timing Role: Low-power ADC interfacing to thermistors and electrochemical sensors; enters SLEEP mode between readings to extend operational lifetime. Use Value: 10 µW standby power and programmable 0.1–10 Hz filter bandwidth enable multi-year battery life while rejecting ambient electrical noise. |
| Portable Instrumentation | Process Control Transmitters |
|
Use Scenario: Handheld multimeters, pH meters, and dissolved oxygen analyzers requiring high DC accuracy and compact form factor. IC Role / Device Role / Timing Role: Core signal digitizer with integrated reference and serial interface; calibrated at power-up to compensate for PCB thermal gradients. Use Value: On-chip self-calibration removes need for factory-trimmed resistors or manual calibration routines, reducing BOM and test time. |
Use Scenario: 4–20 mA loop-powered transmitters converting pressure, flow, or level sensor outputs in hazardous industrial zones. IC Role / Device Role / Timing Role: Isolated-side ADC receiving conditioned analog inputs; communicates via opto-isolated serial link to controller. Use Value: Bipolar ±2.5 V input range and system calibration capability accommodate differential sensor outputs and eliminate zero-shift drift over 15+ year service life. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 16-bit sigma-delta ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7705BN | 2-channel, 16-bit, SPI-compatible, 1 mW typical power, no SLEEP pin, 0.003% INL max | Lacks self-clocking mode and system calibration pins; requires external crystal or clock source; lower integration for multi-sensor systems | Choose when dual-input channel and simpler SPI interface are prioritized over ultra-low-power sleep and system-level calibration flexibility. |
| ADS1220IPWR | 24-bit, 2-channel, PGA, 0.0015% INL, 1.8–3.6 V supply, 0.6 mW active, I²C/SPI | Higher resolution but lower noise immunity at 60 Hz; no built-in Gaussian filter; requires external reference and digital filtering implementation | Choose for higher-resolution DC measurements where external filtering and reference management are acceptable trade-offs for bit depth. |
Compared with AD7701AN, AD7705BN offers channel multiplexing but sacrifices SLEEP-mode power savings and system calibration capability, while ADS1220IPWR delivers greater resolution at the cost of increased design complexity for noise rejection and power supply flexibility.
Availability
AD7701AN is available at Aetrix Electronics and suitable for industrial process control, portable instrumentation, and remote data acquisition requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for AD7701AN 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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA, with design and manufacturing operations worldwide.
The AD7701AN belongs to Analog Devices' precision sigma-delta ADC product line, engineered specifically for high-accuracy, low-frequency measurement of physical, chemical, and biological signals in harsh industrial and portable environments.
FAQ
What is the maximum clock frequency supported by the AD7701AN?
The AD7701AN supports a master clock (CLKIN) frequency of up to 5 MHz, with typical operation at 4.096 MHz. At this frequency, the device achieves a 4 kSPS output data rate and 10 Hz digital filter corner frequency. Operation down to 200 kHz is guaranteed, enabling ultra-low-power configurations where clock frequency is reduced to scale power consumption linearly.
Does the AD7701AN require an external voltage reference?
Yes, the AD7701AN requires an external voltage reference applied to the VREF pin. It is specified for a 2.5 V nominal reference, which sets the full-scale range for both unipolar (0 V to +2.5 V) and bipolar (±2.5 V) input modes. The device does not include an internal reference; using a precision 2.5 V reference such as the REF02 or ADR3425 ensures optimal linearity and temperature stability for the AD7701AN.
How does the AD7701AN handle system-level offset and gain errors?
The AD7701AN supports system-level calibration by allowing external circuitry-including sensor bridges, front-end amplifiers, and RC networks-to be included in the calibration loop. This is achieved by configuring SC1 and SC2 pins during a CAL-initiated cycle. The AD7701AN then measures and corrects for total system offset and gain, not just its own internal errors - a capability confirmed in the AD7701 datasheet Rev. E, page 3, "SYSTEM CALIBRATION" section.
Can the AD7701AN operate from a single supply?
No, the AD7701AN requires dual ±5 V analog supplies (AVDD = +5 V, AVSS = –5 V) and separate digital supplies (DVDD = +5 V, DVSS = –5 V). Its absolute maximum ratings specify AVSS and DVSS down to –6 V, and operation outside the ±4.5 V to ±5.5 V range violates specifications. Single-supply operation is not supported - the architecture relies on true bipolar analog signal handling and charge-balancing modulation.
What is the purpose of the BP/UP pin on the AD7701AN?
The BP/UP (Bipolar/Unipolar) pin on the AD7701AN configures the analog input range: logic low selects unipolar mode (0 V to VREF), and logic high selects bipolar mode (±VREF). This pin directly controls internal gain and code mapping - for example, in bipolar mode, the mid-code transition (0x7FFF → 0x8000) corresponds to 0 V input, enabling signed measurement of differential or AC-coupled signals. Its function is explicitly defined in the AD7701 datasheet Rev. E, page 5, "PIN FUNCTION DESCRIPTIONS".
AD7701AN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Number of Bits:
- 16
- Sampling Rate (Per Second):
- 4k
- Number of Inputs:
- 1
- Input Type:
- Single Ended
- Data Interface:
- SPI
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- Sigma-Delta
- Reference Type:
- External
- Voltage - Supply, Analog:
- 5V
- Voltage - Supply, Digital:
- 5V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 20-PDIP
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
AD7701AN FAQ
1.How can I place an order for AD7701AN through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7701AN 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 AD7701AN reliable?
The price and inventory of AD7701AN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7701AN is usually 5 days.
3.What payment methods are accepted for AD7701AN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7701AN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7701AN?
AD7701AN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7701AN 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 AD7701AN?
For technical support, including AD7701AN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7701AN requirements.
6.How does Aetrix verify that AD7701AN is sourced from the original manufacturer or authorized distributors?
All AD7701AN 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 AD7701AN meets industry standards.
7.What is the process for return or replacement of AD7701AN?
All AD7701AN units undergo pre-shipment inspection (PSI). If there is an issue with AD7701AN, 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 AD7701AN part is unused and in its original packaging.
Return procedure for AD7701AN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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