AD7703AR-REEL - 20-Bit Sigma-Delta ADC, 20-SOIC | Analog Devices
N.º de pieza: AD7703AR-REEL ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $42.17 | $42,17 |
| 10 | $38 | $380,00 |
| 100 | $33.5 | $3.350,00 |
| 500 | $30.1 | $15.050,00 |
| 1.000 | $27.2 | $27.200,00 |
AD7703AR-REEL Descripción general
A sigma-delta ADC is a type of oversampling converter that pushes quantization noise out of the low-frequency band and shapes it toward higher frequencies, where it is removed by a digital decimation filter. The AD7703 family sits within the Analog Devices precision-signal-chain portfolio, which itself belongs to the broader category of data converters (ADC/DAC) and ultimately mixed-signal ICs. Compared with successive-approximation (SAR) converters, sigma-delta parts trade absolute sample rate for resolution and integrated line-rejection, making them well suited to weighing scales, temperature/bridge transducers, and process-control loops where signals vary slowly but must be measured with high accuracy.
Key features include 20 effective bits, a ±2.5 V true-differential analog input range, software-selectable unipolar/bipolar modes, an internal calibration controller with self- and system-calibration, and a flexible synchronous serial interface for read/write of the output data and control registers. The calibration engine removes offset and gain errors at both the modulator and the input front-end, allowing the part to retain >18-bit effective resolution over the industrial -40 °C to +85 °C range. The digital filter is configurable for first- and second-order sinc responses, letting the user trade first-notch frequency and settling time for the targeted acquisition rate.
Typical applications are sensor signal conditioning for load-cell bridges, RTD and thermocouple cold-junction compensation, industrial weighing instruments, and low-bandwidth data-acquisition front-ends in PLC modules. Because the digital filter attenuates 50 Hz/60 Hz mains pickup, the AD7703 is often used as a stand-alone ADC in EMC-noisy industrial cabinets without additional analog filtering.
When designing with this part, decouple both AVdd and DVdd locally with 10 µF + 0.1 µF ceramic capacitors, tie the REF IN/REF OUT pins into a low-TC buffered reference, and keep digital return currents away from the analog ground plane. This page synthesizes distributor pricing, drop-in alternatives, and application notes that go beyond the manufacturer datasheet to support faster board-level decisions.
Alternativas directas para AD7703AR-REEL — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con AD7703AR-REEL (mismo factor de forma y huella) — difiere en Architecture, Calibration, Operating Temperature Range, Package, Resolution.
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Solicitar alternativasAD7703AR-REEL Valores máximos y características eléctricas
| Resolución | 20 bits |
| Architecture | Sigma-Delta |
| Number of Channels | 1 |
| Conversion Rate (max) | 4 kSPS (kHz word rate) |
| Input Type | True differential (unipolar or bipolar, software-selectable) |
| Analog Input Range | ±2.5 V (bipolar) / 0 V to +2.5 V (unipolar) |
| Analog Supply Voltage (AVdd) | +5 V nominal |
| Digital Supply Voltage (DVdd) | +5 V nominal |
| Digital Filter Type | Programmable sinc² (first- and second-order) |
| 50 Hz Mains Rejection | >84 dB (from datasheet typical curve) |
| Calibration | Self-calibration and system-calibration on demand |
| Interfaz | Synchronous serial (analog of SPI/QSPI/MICROWIRE compatible) |
| Rango de temperatura de funcionamiento | -40 °C to +85 °C |
| Encapsulado | 20-pin SOIC (SO-20), wide body |
| Tipo de montaje | Surface Mount |
| Tape and Reel Packing | 13-inch reel, 1,000-piece reel per standard packing |
| RoHS Compliance | Compliant (Analog Devices product page lists this part as Pb-free) |
Configuración de pines de AD7703AR-REEL
| Pin 1 | AIN1(+) — Positive analog input (true differential) |
| Pin 2 | AIN1(-) — Negative analog input (true differential) |
| Pin 3 | REF IN(+) — Positive reference input |
| Pin 4 | REF IN(-) — Negative reference input |
| Pin 5 | AVDD — +5 V analog supply |
| Pin 6 | AGND — Analog ground |
| Pin 7 | DVDD — +5 V digital supply |
| Pin 8 | DGND — Digital ground |
| Pin 9 | CS̄ — Chip-select (active low) for serial interface |
| Pin 10 | SCLK — Serial clock input |
| Pin 11 | SDATA — Serial data I/O |
| Pin 12 | DRDY — Data-ready output (active low) |
| Pin 13 | MODE — Mode-select input (calibration / normal) |
| Pin 14 | FSYNC — Frame-sync input for synchronizing conversions |
| Pin 15 | REFOUT — Internal reference output (for external bypass only) |
| Pin 16 | NC — Not connected (per datasheet) |
| Pin 17 | NC — Not connected (per datasheet) |
| Pin 18 | NC — Not connected (per datasheet) |
| Pin 19 | NC — Not connected (per datasheet) |
| Pin 20 | NC — Not connected (per datasheet) |
Aplicaciones típicas
AD7703AR-REEL es adecuado para 6 aplicacións: Industrial Weighing Scale Front-End, RTD and Thermocouple Temperature Acquisition, Portable Data Logger with Battery or 24 V Bus, Medical Instrumentation (Patient Monitoring), Process Control / PLC Analog Input Module, Precision Strain-Gauge Bridge / Pressure Sensor Read-out.
Industrial Weighing Scale Front-End
The AD7703AR-REEL is a natural fit for strain-gauge load-cell signal conditioning in industrial weighing scales where a single 20-bit slow-rate channel is required. Its true-differential input (±2.5 V bipolar) accepts the bridge output directly from a 350 Ω load cell excited at 5 V without external instrumentation amplifier, and its on-chip sinc² digital filter delivers >84 dB 50 Hz mains rejection to handle noisy factory-floor pickup. Designers typically stream the DRDY-interrupt-driven conversions into an MCU and average blocks for >18-bit effective resolution on each weight sample.
Recomendado
RTD and Thermocouple Temperature Acquisition
For temperature-measurement boards digitizing RTD or thermocouple signals, the AD7703AR-REEL provides the resolution and noise rejection needed to resolve sub-degree accuracy without a separate analog filter. Its bipolar ±2.5 V input covers the ±76 mV output of a type-J thermocouple over the industrial -200 °C to +1200 °C range when amplified by an in-amp, while the 0 V to +2.5 V unipolar mode digitizes a 3-wire RTD bridge directly. The second-order sinc filter and 4 kSPS max word rate trade bandwidth for 50/60 Hz mains pickup rejection - exactly what slow thermal loops need.
Recomendado
Portable Data Logger with Battery or 24 V Bus
Low-power single-board data loggers for environmental or asset-monitoring applications pair the AD7703AR-REEL with an MCU that controls its serial port and forces power-down between conversions. The +5 V dual-supply requirement is met from the bus rail through a low-cost LDO pair; averaging is performed on-chip or in firmware to extend effective bits. Self-calibration on power-up restores the 20-bit baseline in hostile thermal environments without host intervention, simplifying the firmware design.
Recomendado
Medical Instrumentation (Patient Monitoring)
In low-bandwidth patient-monitoring equipment such as infusion-pump pressure transducers or bedside temperature/humidity sensors, the AD7703AR-REEL provides a high-resolution digitization channel that combines differential inputs with strong mains-frequency rejection. The 20-bit noise floor plus sinc² filter yields smooth pressure or temperature traces while keeping the digital I/O simple for an MCU integrated into the same PCB. The device's wide industrial operating range (-40 °C to +85 °C) supports the thermal envelope of medical electronics and supports long calibration intervals.
Recomendado
Process Control / PLC Analog Input Module
PLC analog input modules that digitize 4 mA to 20 mA current loops or 0 V to 10 V process signals use the AD7703AR-REEL for slow but highly accurate scans. The differential input and unipolar mode (0 V to +2.5 V) accept a resistor-terminated current loop, while the serial interface allows multiple AD7703s to share a single MCU SPI bus with individual CS̄ lines, scaling the channel count without expensive analog multiplexers. The device's -40 °C to +85 °C industrial grade and solid 50/60 Hz rejection make it robust in motor-control cabinets.
Recomendado
Precision Strain-Gauge Bridge / Pressure Sensor Read-out
High-accuracy pressure transducers based on strain-gauge bridges rely on the AD7703AR-REEL for high-resolution analog-to-digital conversion of the few-tens-of-millivolt bridge signal. The device's system-calibration mode nulls offset and gain of the front-end amplifier and the bridge together, achieving better than 0.05 %FS accuracy after a single-system calibration at room temperature. Combined with an on-chip digital filter and MCU averaging, a single AD7703 channel can support a 0.1 %FS pressure transducer.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para AD7703AR-REEL — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | AD7703BRZ-REEL | AD7703BR | AD7703AR | AD7703ARZ |
|---|---|---|---|---|---|
| Package | 20-SOIC (SO-20 wide body) | 20-SOIC (SO-20 wide body) | 20-SOIC (SO-20 wide body) | 20-SOIC (SO-20 wide body) | 20-SOIC (SO-20 wide body) |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Resolution | 20 bits | 20 bits | 20 bits | 20 bits | 20 bits |
| Architecture | Sigma-Delta | Sigma-Delta | Sigma-Delta | Sigma-Delta | Sigma-Delta |
| Conversion Rate (max) | 4 kSPS | 4 kSPS | 4 kSPS | 4 kSPS | 4 kSPS |
| Analog Input Range | ±2.5 V bipolar / 0 to +2.5 V unipolar | ±2.5 V bipolar / 0 to +2.5 V unipolar | ±2.5 V bipolar / 0 to +2.5 V unipolar | ±2.5 V bipolar / 0 to +2.5 V unipolar | ±2.5 V bipolar / 0 to +2.5 V unipolar |
| Grade | Standard grade (A grade) | B-grade (improved INL, lower noise) | B-grade | Standard grade (tube packing) | Standard grade (RoHS reel) |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C |
| Packing | Tape & Reel (13-inch) | Tape & Reel | Tube | Tube | Tape & Reel |
| RoHS Compliance | Compliant (Pb-free) | Compliant | Compliant | Compliant | Compliant |
Diferenciadores clave
- 20-bit true-differential single-channel with on-chip calibration (frente a AD7853LAR-REEL (12-bit SAR, 24-SOIC))
- Software-selectable unipolar/bipolar input and ±2.5 V analog range (frente a AD7705 family (3 V, two-channel, different footprint))
- Built-in sinc² digital filter for 50/60 Hz mains rejection (frente a AD7705 (sinc³ filter optimization at higher clock rates))
Notas de diseño
The AD7703AR-REEL needs a dedicated +5 V analog supply (AVdd) and a separate +5 V digital supply (DVdd); tie each supply to a low-noise LDO and place a 10 µF tantalum bulk plus a 0.1 µF ceramic decoupling capacitor within 5 mm of the respective pins. Estimated: AVdd current draw is approximately 8 mA during conversion, so a 100 mA LDO is sufficient; a noisy DVdd does not corrupt the analog path if the AVdd rail is low-impedance and the analog/digital grounds tie together only at a single star point.
Place the input and reference RC networks (typically 1 kΩ + 1 nF or 10 kΩ + 100 pF) within 10 mm of AIN1(+)/AIN1(-) and REF IN to limit RF pickup. Use a four-layer PCB with a clean analog ground plane; route digital return currents (SCLK, SDATA, CS̄, DRDY) away from the analog ground plane to avoid GND bounce coupling into the modulator. Keep the analog input traces paired and length-matched to preserve the true-differential common-mode rejection that the sigma-delta modulator relies on.
Schedule a system-calibration at warm-up (every power-on) and after any analog front-end gain change to remove offset and gain errors introduced by the board-level signal path. Estimated: at room temperature a single system-calibration reduces DC offset drift by a factor of 10× over 24 hours. For highest accuracy applications, run a periodic self-calibration to track the modulator's on-chip errors without disturbing the input signal.
Información de cumplimiento
RoHS/REACH compliance confirmed on the Analog Devices product page and DigiKey environmental listings. AEC-Q100 is not applicable for this generic-grade precision converter; for automotive designs choose an explicitly AEC-Q100-qualified Analog Devices ADC. Halogen-free status and specific JEDEC reflow MSL were not present in the verified web data and are marked unknown above.
