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Analog Devices Inc. AD7708BRZ-REEL
- Part No.:
- AD7708BRZ-REEL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 28-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AD7708BRZ-REEL.pdf
- Description:
- IC ADC 16BIT SIGMA-DELTA 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:970
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Product details
Overview
AD7708BRZ-REEL from Analog Devices is a 16-bit Σ-Δ analog-to-digital converter (ADC) with integrated programmable-gain amplifier (PGA), 8-channel pseudo-differential or 4-channel fully differential input capability, and on-chip 32.768 kHz crystal oscillator with PLL. It delivers up to 16-bit no-missing-codes resolution, 100 dB normal-mode rejection at 50/60 Hz, and operates from single 3 V or 5 V supplies - enabling direct transducer interfacing in industrial sensor signal chains.
For engineers reviewing the AD7708BRZ-REEL datasheet, AD7708BRZ-REEL pinout, AD7708BRZ-REEL application, or AD7708BRZ-REEL equivalent, key selection criteria include its CHOP-enabled low-drift mode (13-bit peak-to-peak resolution at 20 Hz), ratiometric/absolute measurement support via VREF Select™, 3-wire SPI/MICROWIRE/DSP-compatible serial interface, and pin compatibility with the 24-bit AD7718 for scalable system design.
Technical Context
The AD7708BRZ-REEL implements a sigma-delta modulation architecture with a 2nd-order modulator and digital filter, supporting both chop (CHOP = 0) and non-chop (CHOP = 1) operation modes. Its on-chip PGA offers gain settings from 1 to 128, enabling direct digitization of signals from ±20 mV to ±2.56 V full-scale without external amplification.
It features dual reference inputs (REFIN1± and REFIN2±), two configurable digital I/O pins (P1/P2), rail-to-rail input buffers, and simultaneous 50 Hz/60 Hz rejection via programmable output data rate and filter configuration. The device uses separate analog (AVDD/AGND) and digital (DVDD/DGND) supplies for noise isolation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 16-bit no-missing-codes; 13-bit peak-to-peak at ±20 mV range with 20 Hz update rate in CHOP mode |
| Input Channels | 8 pseudo-differential or 4 fully differential inputs; AIN1–AIN8 + AINCOM, with REFIN2± configurable as AIN9/AIN10 |
| PGA Gain Range | 1 to 128; enables direct conversion of low-level transducer outputs (e.g., 20 mV pressure sensor signals) |
| Power Consumption | 1.28 mA typical at 3 V (3.84 mW); 30 µA power-down current with 32.768 kHz oscillator running |
| AC Performance | 100 dB normal-mode rejection at 50/60 Hz; 90 dB min common-mode rejection at DC (±2.56 V range) |
| Reference Support | VREF Select™ allows ratiometric (e.g., bridge sensor) or absolute (e.g., thermocouple with external ref) measurement modes |
| Interface | 3-wire SPI/QSPI/MICROWIRE/DSP-compatible serial interface with Schmitt-triggered SCLK and RDY flag |
Pinout & Package
AD7708BRZ-REEL is housed in a 28-lead SOIC package (R-28), RoHS-compliant and tape-and-reel packaged per the "-REEL" suffix. Pin functions are validated per Analog Devices' official AD7708/AD7718 datasheet Rev. 0, Section "PIN FUNCTION DESCRIPTIONS".
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AIN1–AIN8 | Analog Input Channels | Programmable-gain inputs; configurable as pseudo-differential (vs. AINCOM) or fully differential pairs (e.g., AIN1+/AIN2−) |
| AINCOM | Common Analog Input Reference | Return node for pseudo-differential channels; voltage range: AGND −30 mV to AVDD +30 mV (NEGBUF = 0) |
| REFIN1(±), REFIN2(±) | Reference Inputs | Dual reference pairs; REFIN2(±) can be reconfigured as analog inputs AIN9/AIN10; nominal 2.5 V ref, 1 V to AVDD range |
| AVDD, AGND / DVDD, DGND | Separate Analog & Digital Supplies | Independent 2.7–3.6 V or 4.75–5.25 V supplies; AGND–DGND offset limited to ±50 mV for noise integrity |
| DIN, DOUT, SCLK, CS, RDY | 3-Wire Serial Interface | Synchronous serial I/O; RDY indicates data ready; Schmitt-triggered SCLK supports noisy environments |
| P1, P2 | Configurable Digital I/O Port | 2-bit bidirectional port; software-controllable for system signaling or status indication |
| XTAL1/XTAL2 | Crystal Oscillator Terminals | Supports 32.768 kHz crystal; internal buffer and PLL generate internal clock - no external clock source required |
Key Features
| Feature | Design Value |
|---|---|
| Factory-calibrated 16-bit ADC | Eliminates need for user calibration; INL ±15 ppm FSR max, offset error ±0.65 LSB after self-calibration |
| Programmable CHOP mode | Reduces offset drift to ±10 nV/°C and improves PSR to 100 dB typ - critical for precision DC measurements |
| VREF Select™ architecture | Enables seamless switching between ratiometric (e.g., strain gauge) and absolute (e.g., RTD with 2.5 V ref) configurations |
| Simultaneous 50/60 Hz rejection | Hardware-filtered line-frequency interference without firmware overhead - essential for industrial AC environments |
| Single-supply 3 V/5 V operation | Reduces BOM count and simplifies power design; AVDD/DVDD may be independently powered or tied together |
Applications
| Industrial Process Control | Portable Instrumentation |
|---|---|
Use Scenario: Monitoring temperature, pressure, and flow in PLC-based factory automation systems with 4–20 mA loop integration. IC Role / Device Role / Timing Role: Front-end ADC digitizing conditioned sensor outputs; handles multiplexed 8-channel scanning with auto-calibration. Use Value: 100 dB 50/60 Hz rejection ensures stable readings in electrically noisy plant floors without external notch filters. |
Use Scenario: Battery-powered handheld multimeters and environmental data loggers requiring low power and high accuracy. IC Role / Device Role / Timing Role: Core signal acquisition IC; operates in power-down mode (30 µA) between measurements to extend battery life. Use Value: 1.28 mA typical active current at 3 V enables >100-hour runtime on two AA cells while maintaining 16-bit integrity. |
| Smart Transmitters | Pressure Transducers |
Use Scenario: HART-enabled 2-wire field transmitters converting sensor data for digital communication over analog loops. IC Role / Device Role / Timing Role: Precision ADC with ratiometric capability for bridge-based sensors; interfaces directly to microcontroller UART/HART modem. Use Value: VREF Select™ allows same hardware to support both ratiometric bridge sensors and absolute reference sensors - reducing SKU count. |
Use Scenario: MEMS or piezoresistive pressure sensors outputting mV-level signals in medical or HVAC applications. IC Role / Device Role / Timing Role: Signal chain integrator; PGA gain ×128 amplifies ±20 mV sensor output to full-scale ADC range without external op-amps. Use Value: Direct transducer-to-digital conversion reduces component count, board area, and thermal drift sources. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar precision ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7718BRZ | 24-bit resolution, identical pinout and register map; higher noise performance (18-bit p-p at ±2.56 V, 20 Hz) | Required when >16-bit dynamic range or lower effective resolution noise is needed (e.g., high-precision weigh scales) | Select AD7718BRZ only if system requires >16-bit ENOB; AD7708BRZ-REEL remains optimal for cost-sensitive 16-bit applications. |
| ADS124S08IPWR | Texas Instruments 24-bit delta-sigma ADC; 12-channel, integrated PGA, but no on-chip oscillator or CHOP mode | Lacks simultaneous 50/60 Hz rejection and factory calibration; requires external clock and more calibration effort | Choose ADS124S08IPWR only if higher channel count (12 vs. 8) outweighs loss of built-in line-frequency rejection and simplified startup. |
Compared with AD7718BRZ, AD7708BRZ-REEL trades resolution for lower cost and smaller code footprint; compared with ADS124S08IPWR, it delivers superior out-of-box 50/60 Hz immunity and reduced system-level calibration burden - critical for industrial field deployments.
Availability
AD7708BRZ-REEL is available at Aetrix Electronics and suitable for industrial process control, portable instrumentation, and smart transmitter designs requiring stable component supply, long-term lifecycle support, and RoHS-compliant SOIC packaging.
Supply support for AD7708BRZ-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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.
The AD7708 is part of Analog Devices' precision sigma-delta ADC product line, designed specifically for low-frequency, high-accuracy measurement applications including sensor front-ends, industrial PLCs, and portable test equipment.
FAQ
What is the maximum sample rate of the AD7708BRZ-REEL in non-chop mode?
The AD7708BRZ-REEL achieves a maximum output update rate of 1.365 kHz in non-chop (CHOP = 1) mode. This corresponds to a minimum conversion time of approximately 732 µs per sample, enabling moderate-speed data acquisition while retaining 16-bit no-missing-codes performance and 100 dB 50/60 Hz rejection.
Does the AD7708BRZ-REEL require an external crystal or clock source?
No - the AD7708BRZ-REEL integrates a crystal input buffer and on-chip PLL that accepts a 32.768 kHz crystal connected to XTAL1/XTAL2. It generates all internal clocks autonomously; no external oscillator or clock generator is needed, simplifying layout and reducing BOM cost.
Can the AD7708BRZ-REEL measure both ratiometric and absolute reference signals?
Yes - the AD7708BRZ-REEL implements Analog Devices' VREF Select™ feature, allowing software-selectable ratiometric measurement (using sensor excitation as reference) or absolute measurement (using a stable external reference). This is enabled by dual reference inputs REFIN1± and REFIN2±, with REFIN2± configurable as AIN9/AIN10.
What is the purpose of the CHOP mode in the AD7708BRZ-REEL?
CHOP mode (CHOP = 0) in the AD7708BRZ-REEL periodically swaps amplifier inputs to cancel offset voltage and 1/f noise, reducing offset drift to ±10 nV/°C and improving power supply rejection to 100 dB typ. It is ideal for high-stability DC measurements like temperature monitoring, though it limits max update rate to 105 Hz.
Is the AD7708BRZ-REEL pin-compatible with any higher-resolution alternatives?
Yes - the AD7708BRZ-REEL is pin-for-pin compatible with the AD7718BRZ (24-bit version). Both share identical 28-lead SOIC packaging, register map, pin functions, and timing, enabling hardware-upgradable system designs without PCB revision when higher resolution is later required.
AD7708BRZ-REEL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Number of Bits:
- 16
- Sampling Rate (Per Second):
- 1.37k
- Number of Inputs:
- 4, 8
- Input Type:
- Differential, Pseudo-Differential, Single Ended
- Data Interface:
- SPI, DSP
- Configuration:
- MUX-PGA-ADC
- Ratio - S/H:ADC:
- -
- Number of A/D Converters:
- 1
- Architecture:
- Sigma-Delta
- Reference Type:
- External
- Voltage - Supply, Analog:
- 2.7V ~ 3.3V, 5V
- Voltage - Supply, Digital:
- 2.7V ~ 3.3V, 5V
- Features:
- PGA
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 28-SOIC
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7708BRZ-REEL FAQ
1.How can I place an order for AD7708BRZ-REEL through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7708BRZ-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 AD7708BRZ-REEL reliable?
The price and inventory of AD7708BRZ-REEL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7708BRZ-REEL is usually 5 days.
3.What payment methods are accepted for AD7708BRZ-REEL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7708BRZ-REEL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7708BRZ-REEL?
AD7708BRZ-REEL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7708BRZ-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 AD7708BRZ-REEL?
For technical support, including AD7708BRZ-REEL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7708BRZ-REEL requirements.
6.How does Aetrix verify that AD7708BRZ-REEL is sourced from the original manufacturer or authorized distributors?
All AD7708BRZ-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 AD7708BRZ-REEL meets industry standards.
7.What is the process for return or replacement of AD7708BRZ-REEL?
All AD7708BRZ-REEL units undergo pre-shipment inspection (PSI). If there is an issue with AD7708BRZ-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 AD7708BRZ-REEL part is unused and in its original packaging.
Return procedure for AD7708BRZ-REEL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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