My Inquiry
My Account
Analog Devices Inc. AD7708BR-REEL7
- Part No.:
- AD7708BR-REEL7
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 28-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AD7708BR-REEL7.pdf
- Description:
- IC ADC 16BIT SIGMA-DELTA 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,339
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
AD7708BR-REEL7 from Analog Devices is a 16-bit Σ-Δ analog-to-digital converter optimized for low-frequency, high-precision measurement applications. It features 8 pseudo-differential or 4 fully-differential input channels, programmable gain (1–128), simultaneous 50 Hz/60 Hz rejection, and operates from single 3 V or 5 V supplies with typical power dissipation of 3.84 mW at 3 V. It is used in industrial process control systems to digitize transducer outputs without external signal conditioning.
For engineers reviewing the AD7708BR-REEL7 datasheet, AD7708BR-REEL7 pinout, AD7708BR-REEL7 application, or AD7708BR-REEL7 equivalent, key selection considerations include its 16-bit resolution with up to 16 bits peak-to-peak noise performance, CHOP mode vs. non-CHOP trade-offs for throughput versus noise, VREF Select™ capability for ratiometric or absolute measurements, and pin compatibility with the 24-bit AD7718 for scalable system design.
Technical Context
The AD7708BR-REEL7 integrates a rail-to-rail input buffer, programmable gain amplifier (PGA), on-chip oscillator (32.768 kHz crystal), PLL, and serial interface logic. Its Σ-Δ architecture supports software-programmable output data rates from 5.4 Hz (CHOP enabled) to 1.365 kHz (CHOP disabled), with configurable unipolar/bipolar coding and self-calibration routines.
It implements dual reference inputs (REFIN1 and REFIN2), two of which are multiplexed with analog input pins (AIN9/AIN10), enabling flexible reference sourcing. The device includes a 2-bit digital I/O port and supports SPI/QSPI/MICROWIRE/DSP-compatible 3-wire serial communication with Schmitt-triggered SCLK.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 16-bit no-missing-codes; 13–16 bits peak-to-peak depending on gain and update rate |
| Input Channels | 8 pseudo-differential or 4 fully-differential inputs; AIN1–AIN8 plus AINCOM, with REFIN1(±)/AIN9–AIN10 configurable as inputs |
| Programmable Gain | 1 to 128; enables direct conversion of signals from ±20 mV to ±2.56 V full-scale |
| Power Supply | Single 3 V or 5 V supply; AVDD and DVDD independently operable; 1.28 mA typical current at 3 V |
| Rejection Performance | 100 dB normal-mode rejection at 50/60 Hz; 90–110 dB common-mode rejection depending on range and CHOP setting |
| Interface | 3-wire serial (DIN/DOUT/SCLK), CS and RDY control; SPI/QSPI/MICROWIRE/DSP compatible |
| Operating Temperature | –40°C to +85°C; qualified for industrial environments |
Pinout & Package
The AD7708BR-REEL7 is housed in a 28-lead SOIC package (R-28), RoHS-compliant and tape-and-reel packaged per the -REEL7 suffix.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AIN1–AIN8 | Analog Input Channels | Programmable-gain inputs supporting pseudo-differential (vs. AINCOM) or fully-differential (paired) configurations |
| AINCOM | Common Analog Input Reference | Reference node for pseudo-differential operation; voltage range AGND–30 mV to AVDD+30 mV (NEGBUF=0) |
| REFIN1(+), REFIN1(–) | Primary Reference Inputs | Dedicated reference pair; nominal 2.5 V differential, functional from 1 V to AVDD |
| REFIN2(+)/AIN9, REFIN2(–)/AIN10 | Configurable Reference/Input Pins | Multi-function terminals usable as secondary reference inputs or additional analog inputs per register configuration |
| AVDD, AGND | Analog Power & Ground | Separate analog supply domain; AGND must be tied to DGND within ±50 mV for specified performance |
| DVDD, DGND | Digital Power & Ground | Independent digital supply domain; supports 2.7–3.6 V or 4.75–5.25 V operation |
| DIN, DOUT, SCLK, CS, RDY | Serial Interface Signals | 3-wire SPI-compatible interface; SCLK has Schmitt trigger; RDY indicates data ready status |
| XTAL1, XTAL2 | Crystal Oscillator Inputs | Accepts 32.768 kHz crystal; internal buffer and PLL generate required internal clock |
| P1, P2 | Digital I/O Port | 2-bit general-purpose bidirectional port; levels referenced to AVDD/AGND |
| RESET | Hardware Reset Input | Active-low asynchronous reset; minimum pulse width 50 ns |
Key Features
| Feature | Design Value |
|---|---|
| VREF Select™ | Enables seamless switching between ratiometric (e.g., bridge sensor) and absolute (e.g., thermocouple) measurement modes using same hardware |
| Simultaneous 50 Hz/60 Hz Rejection | Eliminates mains interference without external notch filters-critical for portable instrumentation in global deployments |
| CHOP Mode (CHOP = 0) | Reduces offset drift to ±10 nV/°C and improves PSR to 100 dB, at cost of reduced max update rate (105 Hz) |
| Factory-Calibrated Architecture | Guarantees ±15 ppm INL and ±0.75 LSB full-scale error after self-calibration-reduces system-level calibration burden |
| Pin Compatibility with AD7718 | Allows hardware reuse when upgrading from 16-bit to 24-bit resolution-no PCB redesign required for migration path |
Applications
| Industrial Process Control | Portable Instrumentation |
|---|---|
Use Scenario: Monitoring pressure, temperature, and flow in distributed PLC-based control cabinets with limited board space and thermal budget. IC Role / Device Role / Timing Role: Primary ADC front-end converting 4–20 mA loop signals and RTD/thermocouple outputs with integrated PGA and reference. Use Value: Eliminates need for external op-amps, precision references, and anti-aliasing filters-reducing BOM count by ≥5 components per channel. | Use Scenario: Battery-powered handheld multimeters and environmental sensors requiring long runtime and high DC accuracy. IC Role / Device Role / Timing Role: Low-power, high-resolution ADC core with 3.84 mW typical dissipation at 3 V and 1 µA power-down current. Use Value: Enables >500-hour battery life in continuous measurement mode while maintaining 16-bit integrity across –40°C to +85°C. |
| Smart Transmitters | Pressure Transducers |
Use Scenario: HART-enabled field transmitters where digital communication coexists with analog 4–20 mA output and local diagnostics. IC Role / Device Role / Timing Role: Precision sensor digitizer with integrated 2-bit I/O port for status LED control and HART modem interface coordination. Use Value: Reduces component count and layout area by integrating functions otherwise requiring discrete GPIO expanders and level shifters. | Use Scenario: Wheatstone bridge-based pressure sensing in HVAC and medical devices requiring stable zero and span over temperature. IC Role / Device Role / Timing Role: Ratiometric ADC with VREF Select™ using bridge excitation voltage as reference-rejecting supply variations. Use Value: Achieves <0.003% FSR negative full-scale error and ±0.5 ppm/°C gain drift-enabling Class 0.1 pressure accuracy without trimming. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-precision sigma-delta ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7718BR-REEL7 | 24-bit resolution, identical pinout and register map; higher noise performance (13–18 bits p-p), lower max throughput in CHOP mode (105 Hz vs. 105 Hz), same power specs | Required for sub-10 ppm system accuracy, e.g., laboratory-grade weigh scales or metrology equipment | Select when resolution and noise floor outweigh update rate needs; drop-in replacement with firmware register updates only |
| ADS124S08IPWR | 24-bit, 4-kSPS max, integrated PGA (1–128), but uses internal oscillator (no crystal required); different pinout (32-QFN), no CHOP mode, lower CMRR (105 dB typ) | Suitable for high-throughput sensor nodes where crystal footprint and CHOP timing constraints are prohibitive | Choose for simplified layout and faster sampling; requires PCB redesign and driver adaptation due to non-pin-compatible packaging and interface differences |
Compared with AD7718BR-REEL7, the AD7708BR-REEL7 trades resolution for deterministic timing and lower firmware complexity; compared with ADS124S08IPWR, it offers superior noise rejection at line frequencies and proven industrial reliability-but demands crystal layout and stricter grounding.
Availability
AD7708BR-REEL7 is available at Aetrix Electronics and suitable for industrial process control, portable instrumentation, and smart transmitter designs requiring stable component supply, long-term manufacturability, and guaranteed traceability.
Supply support for AD7708BR-REEL7 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 Σ-Δ ADC product line, designed specifically for low-frequency, high-accuracy industrial and instrumentation applications where noise, drift, and power efficiency are critical.
FAQ
What is the maximum update rate of the AD7708BR-REEL7 in non-CHOP mode?
The AD7708BR-REEL7 achieves a maximum output update rate of 1.365 kHz in non-CHOP mode (CHOP = 1), enabling faster channel scanning in multiplexed data acquisition systems while maintaining 16-bit no-missing-codes performance. This rate is achieved with SF word = 69 and gain = 1, as specified in the AD7708 (CHOP DISABLED) section of the datasheet. At higher gains or with filtering enabled, the rate decreases proportionally.
Does the AD7708BR-REEL7 require an external crystal?
Yes, the AD7708BR-REEL7 requires a 32.768 kHz crystal connected between XTAL1 and XTAL2 pins to operate-the internal oscillator buffer and PLL depend on this frequency to generate all internal clocks. Unlike some newer ADCs, it does not support internal RC oscillators or alternative clock sources; omitting the crystal prevents initialization and data conversion.
How does VREF Select™ work on the AD7708BR-REEL7?
VREF Select™ on the AD7708BR-REEL7 allows dynamic selection of reference source via configuration registers: REFIN1(±) can serve as the primary reference for absolute measurements, while REFIN2(±)/AIN9–AIN10 can be configured to use the same excitation voltage applied to a sensor bridge-enabling true ratiometric conversion. This eliminates ratio errors caused by supply drift and simplifies calibration in smart transmitter designs using the AD7708BR-REEL7.
Can the AD7708BR-REEL7 interface directly with a 3.3 V microcontroller SPI bus?
Yes, the AD7708BR-REEL7 supports 3.3 V digital operation: its logic inputs accept VINH ≥ 2.0 V and VINL ≤ 0.4 V at DVDD = 3 V, and outputs drive VOH ≥ DVDD – 0.6 V and VOL ≤ 0.4 V at 100 µA load-fully compatible with standard 3.3 V SPI peripherals. Level-shifting is unnecessary when DVDD = 3.3 V and the host MCU shares the same ground reference.
What is the purpose of the P1 and P2 pins on the AD7708BR-REEL7?
The P1 and P2 pins on the AD7708BR-REEL7 form a 2-bit digital I/O port, configurable as inputs or outputs via the I/O Control Register. They are referenced to AVDD/AGND-not DVDD/DGND-making them suitable for monitoring analog subsystem status (e.g., sensor fault flags) or driving LEDs directly from the analog domain, reducing inter-domain signal coupling in noise-sensitive applications using the AD7708BR-REEL7.
AD7708BR-REEL7 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:
- Obsolete
- 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:
- -
AD7708BR-REEL7 FAQ
1.How can I place an order for AD7708BR-REEL7 through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7708BR-REEL7 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 AD7708BR-REEL7 reliable?
The price and inventory of AD7708BR-REEL7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7708BR-REEL7 is usually 5 days.
3.What payment methods are accepted for AD7708BR-REEL7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7708BR-REEL7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7708BR-REEL7?
AD7708BR-REEL7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7708BR-REEL7 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 AD7708BR-REEL7?
For technical support, including AD7708BR-REEL7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7708BR-REEL7 requirements.
6.How does Aetrix verify that AD7708BR-REEL7 is sourced from the original manufacturer or authorized distributors?
All AD7708BR-REEL7 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 AD7708BR-REEL7 meets industry standards.
7.What is the process for return or replacement of AD7708BR-REEL7?
All AD7708BR-REEL7 units undergo pre-shipment inspection (PSI). If there is an issue with AD7708BR-REEL7, 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 AD7708BR-REEL7 part is unused and in its original packaging.
Return procedure for AD7708BR-REEL7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AD7708BR-REEL7 Tags
-
ADC081C021CIMKX/NOPB
Texas Instruments
-
MCP3021A5T-E/OT
Microchip Technology
-
TLA2024IRUGR
Texas Instruments
-
MCP3221A5T-E/OT
Microchip Technology
-
MCP3221A5T-I/OT
Microchip Technology
-
MCP3221A4T-E/OT
Microchip Technology
-
MCP3221A6T-E/OT
Microchip Technology
-
MCP3221A0T-E/OT
Microchip Technology
-
MCP3221A1T-E/OT
Microchip Technology
-
ADC121S021CIMFX/NOPB
Texas Instruments
-
MCP3001-I/MS
Microchip Technology
-
MCP3001-I/SN
Microchip Technology
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
