AD7703AR-REEL - 20-Bit Sigma-Delta ADC, 20-SOIC | Analog Devices
MPN: AD7703AR-REEL ✓ Hoạt độngAD7703AR-REEL Tóm tắt
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.
Bộ thay thế dễ dàng lắp đặt cho AD7703AR-REEL — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với AD7703AR-REEL (cùng hình factor và footprint) — khác nhau ở Architecture, Calibration, Operating Temperature Range, Package, Resolution.
AD7703BRZ-REEL
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
AD7703BR
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
AD7703AR
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →AD7703ARZ
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
AD7703ARZ-REEL
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
AD7703AR-REEL Tỷ lệ tối đa & tính chất điện
| Độ phân giải | 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 |
| Giao diện | Synchronous serial (analog of SPI/QSPI/MICROWIRE compatible) |
| Khoảng nhiệt độ hoạt động | -40 °C to +85 °C |
| Hộp | 20-pin SOIC (SO-20), wide body |
| Kiểu lắp đặt | 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) |
Cấu hình chân AD7703AR-REEL
| Chân 1 | AIN1(+) — Positive analog input (true differential) |
| Chân 2 | AIN1(-) — Negative analog input (true differential) |
| Chân 3 | REF IN(+) — Positive reference input |
| Chân 4 | REF IN(-) — Negative reference input |
| Chân 5 | AVDD — +5 V analog supply |
| Chân 6 | AGND — Analog ground |
| Chân 7 | DVDD — +5 V digital supply |
| Chân 8 | DGND — Digital ground |
| Chân 9 | CS̄ — Chip-select (active low) for serial interface |
| Chân 10 | SCLK — Serial clock input |
| Chân 11 | SDATA — Serial data I/O |
| Chân 12 | DRDY — Data-ready output (active low) |
| Chân 13 | MODE — Mode-select input (calibration / normal) |
| Chân 14 | FSYNC — Frame-sync input for synchronizing conversions |
| Chân 15 | REFOUT — Internal reference output (for external bypass only) |
| Chân 16 | NC — Not connected (per datasheet) |
| Chân 17 | NC — Not connected (per datasheet) |
| Chân 18 | NC — Not connected (per datasheet) |
| Chân 19 | NC — Not connected (per datasheet) |
| Chân 20 | NC — Not connected (per datasheet) |
Ứng dụng tiêu biểu
AD7703AR-REEL phù hợp cho 6 Áp dụngs: 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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho AD7703AR-REEL — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | 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 |
Bảo phân biệt quan trọng
- 20-bit true-differential single-channel with on-chip calibration (vsAD7853LAR-REEL (12-bit SAR, 24-SOIC))
- Software-selectable unipolar/bipolar input and ±2.5 V analog range (vsAD7705 family (3 V, two-channel, different footprint))
- Built-in sinc² digital filter for 50/60 Hz mains rejection (vsAD7705 (sinc³ filter optimization at higher clock rates))
Ghi chú thiết kế
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.
Thông tin tuân thủ
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.
