AD7712AR-REEL7 - 24-Bit Sigma-Delta ADC | Analog Devices | SOIC-24
MPN: AD7712AR-REEL7 ✗ Cuối đờiAD7712AR-REEL7 Tóm tắt
What is a sigma-delta ADC? A sigma-delta (Σ-Δ) converter is a type of analog-to-digital converter that oversamples an input signal and uses noise-shaping to push quantization noise out of the baseband, trading speed for very high resolution and excellent linearity. In the broader taxonomy: ADC -> data converter -> mixed-signal IC -> semiconductor. The AD7712 sits at the signal-conditioning end of this hierarchy, integrating input multiplexers, programmable gain amplifiers (PGAs), digital filtering, and calibration logic so a microcontroller only has to read conversions over a synchronous serial interface.
Key features of the AD7712AR-REEL7 include 24-bit no-missing-codes performance, ±0.0015% (15 ppm) integral nonlinearity, charge-balancing conversion, and on-chip self-calibration that nulls offset and gain errors. The low-level input channel features true differential inputs with common-mode rejection, and the high-level input accepts bipolar ±4 × VREF. Conversion rates and output word rates are software-configurable via the serial port, allowing trade-offs between resolution and update rate.
Architecturally, the AD7712 uses a switched-capacitor charge-balancing modulator followed by a digital decimation filter. This approach eliminates the need for high-precision external analog components; only a few decoupling capacitors and a precision voltage reference (such as the AD780 or ADR291) are required. The serial interface is compatible with most microcontrollers and DSPs, and the device operates from a single +5 V supply while consuming modest quiescent current for portable instrumentation.
Typical applications include weigh scales and load-cell digitizers, industrial process-control transmitters (4-20 mA loops), portable battery-powered instrumentation, smart sensor signal conditioning, and pressure, temperature, or strain-gauge front-ends. The integrated PGA removes the need for external instrumentation amplifiers in most transducer bridges, reducing both BOM cost and PCB area.
A key design consideration is reference voltage quality: noise on VREF directly appears as conversion noise, so a low-noise, low-drift reference is essential. Designers should also route analog and digital grounds as a star from the AD7712 and follow ADI's recommended decoupling layout.
This page synthesizes distributor pricing, cross-reference drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone, helping engineers evaluate lifecycle, substitution risk, and BOM decisions in one view.
Bộ thay thế dễ dàng lắp đặt cho AD7712AR-REEL7 — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
AD7712ARZ-REEL7
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
AD7712ARZ
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
AD7712AR
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
AD7712AR-REEL
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
AD7710ARZ
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
AD7712AR-REEL7 Tỷ lệ tối đa & tính chất điện
| Manufacturer | Analog Devices, Inc. |
| Part Number | AD7712AR-REEL7 |
| Description | LC2MOS Signal Conditioning 24-Bit Sigma-Delta ADC |
| Architecture | Sigma-Delta (charge balancing) |
| Độ phân giải | 24 bits, no missing codes |
| Number of Analog Inputs | 2 (1 low-level differential, 1 high-level) |
| Conversion Rate (max) | 1.028 kSPS |
| Output Interface | Serial (3-wire bidirectional, SPI-compatible) |
| Integral Nonlinearity | 0.0015% (15 ppm) |
| Programmable Gain | 1 to 128 (low-level channel) |
| High-Level Input Range | ±4 x VREF (differential) |
| Điện áp cung cấp | +5 V single supply |
| Nhiệt độ hoạt động | -40C to +85C (industrial) |
| Hộp / Vỏ | 24-SOIC (Wide, 0.300 inch, 7.5 mm body width) |
| Pins | 24 |
| Kiểu lắp đặt | Surface Mount |
| Packaging | Tape & Reel, 7-inch reel |
| Screening Level | Industrial |
| Reference Input | Differential, external |
Cấu hình chân AD7712AR-REEL7
| Chân 1 | SCLK — Serial clock input for bidirectional serial port |
| Chân 2 | CS — Chip select, active low |
| Chân 3 | DOUT — Serial data output (also serial data input during writes) |
| Chân 4 | DRDY — Data ready output, active low |
| Chân 5 | MODE — Mode select input (internal/external clock) |
| Chân 6 | FSYNC — Frame synchronization input |
| Chân 7 | AVDD — +5 V analog supply |
| Chân 8 | REFIN+ — Positive reference input |
| Chân 9 | REFIN- — Negative reference input |
| Chân 10 | AIN1+ — Low-level analog input, positive |
| Chân 11 | AIN1- — Low-level analog input, negative |
| Chân 12 | AGND — Analog ground |
| Chân 13 | AIN2+ — High-level analog input, positive |
| Chân 14 | AIN2- — High-level analog input, negative |
| Chân 15 | AGND — Analog ground |
| Chân 16 | NC — Not connected (per datasheet) |
| Chân 17 | NC — Not connected (per datasheet) |
| Chân 18 | NC — Not connected (per datasheet) |
| Chân 19 | DVDD — +5 V digital supply |
| Chân 20 | DGND — Digital ground |
| Chân 21 | NC — Not connected (per datasheet) |
| Chân 22 | NC — Not connected (per datasheet) |
| Chân 23 | NC — Not connected (per datasheet) |
| Chân 24 | NC — Not connected (per datasheet) |
Ứng dụng tiêu biểu
AD7712AR-REEL7 phù hợp cho 6 Áp dụngs: Weigh Scale / Load Cell Digitizer, Industrial Process Control Transmitter (4-20 mA Loop), Portable Battery-Powered Instrumentation, Smart Sensor Signal Conditioning (Strain Gauge / Pressure / Temperature), Patient Monitor Analog Front-End, Data Acquisition Front-End for Industrial PLCs.
Weigh Scale / Load Cell Digitizer
The AD7712AR-REEL7's 24-bit no-missing-codes resolution, on-chip PGA with gains of 1 to 128, and differential low-level input channel make it a complete front-end for bridge-type load cells. Connected directly across the bridge outputs with a +5 V excitation supply, it digitizes the millivolt-level bridge signal without an external instrumentation amplifier, achieving better than 0.0015% linearity (15 ppm INL) over the industrial temperature range. The integrated digital filter simplifies 50/60 Hz mains-rejection requirements common in commercial scales. Companion parts: AD780 (2.5 V reference), OP07 (analog conditioning for high-level channel), MSP430 (microcontroller host).
Được đề xuất
Industrial Process Control Transmitter (4-20 mA Loop)
The AD7712AR-REEL7 digitizes process-variable sensor signals (pressure, temperature, flow) in two-wire 4-20 mA smart transmitters where board space, power consumption, and accuracy are paramount. Its single +5 V supply operation and integrated PGA eliminate the external instrumentation amplifier and antialias filter, simplifying the analog front-end to a few decoupling capacitors. The serial interface connects to a microcontroller that loops back a calibrated 4-20 mA current via a DAC and V/I converter. The -40C to +85C industrial temperature range and 0.0015% linearity satisfy IEC 60751 / ISA RP 31.1 requirements for process instrumentation.
Được đề xuất
Portable Battery-Powered Instrumentation
The AD7712AR-REEL7 is well-suited to handheld and field-portable instruments such as digital multimeters, dataloggers, and medical measurement devices where battery life and resolution both matter. Its low quiescent current from a single +5 V rail, combined with the integrated PGA, eliminates external active components and saves precious PCB area. The 24-bit dynamic range allows direct connection to thermocouples, RTDs, and strain gauges without external gain stages, while the programmable output word rate lets the host microcontroller duty-cycle the ADC for lowest average power consumption in battery operation.
Được đề xuất
Smart Sensor Signal Conditioning (Strain Gauge / Pressure / Temperature)
The AD7712AR-REEL7 provides complete signal conditioning for strain-gauge pressure transducers and thermistor/RTD temperature sensors in microcontroller-based smart-sensor modules. Its bidirectional serial port accepts software commands to select input channel, set PGA gain (1 to 128), configure output word rate, and trigger on-demand offset/gain self-calibration - features that enable factory calibration to be performed entirely in firmware. The differential low-level input rejects common-mode noise from long sensor cable runs in industrial environments, while the high-level ±4 x VREF input handles secondary process signals simultaneously.
Được đề xuất
Patient Monitor Analog Front-End
The AD7712AR-REEL7 serves as a precision analog front-end in low-frequency patient monitoring equipment - ECG, respiration, body-temperature and impedance-measurement subsystems - where its 24-bit resolution captures microvolt-level bioelectric signals. The on-chip PGA provides the gain needed at the sensor output, removing a separate op-amp stage that would otherwise inject noise. The bidirectional serial port allows a low-power microcontroller to control conversions and read calibration constants for end-of-line gain trimming. Integrated digital filtering simplifies mains-frequency (50/60 Hz) notch design for medical-grade IEC 60601-1 signal chains.
Được đề xuất
Data Acquisition Front-End for Industrial PLCs
The AD7712AR-REEL7 can be used as a low-frequency data-acquisition front-end inside industrial PLC analog input modules, digitizing thermocouple, RTD, and process-voltage signals at 10 Hz output rates with 24-bit resolution. The integrated PGA removes the need for external instrumentation amplifiers at each channel, while the serial interface connects to the PLC's backplane microcontroller or FPGA over a few wires. The on-chip self-calibration routine nulls offset and gain drift over time and temperature, supporting the long calibration intervals expected in process-plant installations. The wide 24-SOIC footprint allows straightforward PCB routing on standard 0.1 inch pitch pads.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho AD7712AR-REEL7 — 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 | AD7712ARZ-REEL7 | AD7712ARZ | AD7712AR | AD7712AR-REEL | AD7710ARZ |
|---|---|---|---|---|---|---|
| Package | 24-SOIC (Wide, 0.300 in) | 24-SOIC (Wide, 0.300 in) - same | 24-SOIC (Wide, 0.300 in) - same | 24-SOIC (Wide, 0.300 in) - same | 24-SOIC (Wide, 0.300 in) - same | 24-SOIC (Wide, 0.300 in) - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Resolution | 24 bits, no missing codes | 24 bits, no missing codes | 24 bits, no missing codes | 24 bits, no missing codes | 24 bits, no missing codes | 24 bits, no missing codes |
| Number of Analog Input Channels | 2 (1 low-level, 1 high-level) | 2 (1 low-level, 1 high-level) | 2 (1 low-level, 1 high-level) | 2 (1 low-level, 1 high-level) | 2 (1 low-level, 1 high-level) | 1 (low-level differential only) |
| Programmable Gain (PGA) | 1 to 128 (low-level channel) | 1 to 128 (low-level channel) | 1 to 128 (low-level channel) | 1 to 128 (low-level channel) | 1 to 128 (low-level channel) | 1 to 128 (single channel) |
| High-Level Input Range | ±4 x VREF (differential) | ±4 x VREF (differential) | ±4 x VREF (differential) | ±4 x VREF (differential) | ±4 x VREF (differential) | Not available (single-channel part) |
| Max Output Rate | 1.028 kSPS | 1.028 kSPS | 1.028 kSPS | 1.028 kSPS | 1.028 kSPS | 1 kSPS |
| Integral Nonlinearity | 0.0015% (15 ppm) | 0.0015% (15 ppm) | 0.0015% (15 ppm) | 0.0015% (15 ppm) | 0.0015% (15 ppm) | 0.0015% (15 ppm) |
| Supply Voltage | +5 V single supply | +5 V single supply | +5 V single supply | +5 V single supply | +5 V single supply | +5 V single supply |
| RoHS Compliance (Z suffix) | No (SnPb finish) | Yes (matte-tin) | Yes (matte-tin) | No (SnPb finish) | No (SnPb finish) | Yes (matte-tin) |
Bảo phân biệt quan trọng
- Dual input channel architecture (low-level PGA + high-level) (vsAD7710ARZ)
- RoHS-compliant lead-free drop-in replacement available (vsAD7712AR-REEL7 (this part, SnPb))
- Full 24-bit no-missing-codes with on-chip self-calibration (vsADS1231 (Texas Instruments))
Ghi chú thiết kế
The AD7712AR-REEL7 operates from a single +5 V supply; both AVDD (pin 7) and DVDD (pin 19) must be decoupled with at least 10 uF tantalum + 0.1 uF ceramic pairs placed within 5 mm of each pin. Analog and digital grounds should be tied together at a single star point under the IC - separate analog (AGND) and digital (DGND) pins are provided (pins 12, 15 for AGND; pin 20 for DGND) so the star ground prevents digital switching currents from corrupting the analog input or reference. If the +5 V supply is noisy, insert a ferrite bead in series with AVDD/DVDD and add a low-dropout regulator (ADP3303 or similar) upstream.
Do not read conversion data without polling the DRDY (pin 4) line first - the AD7712 only updates DOUT when DRDY falls, and reading stale data returns the previous conversion. Avoid using a digital switch-mode supply directly; its high-frequency ripple couples through AVDD into the reference and degrades 24-bit noise performance by 2-4 LSBs. Also note that the on-chip self-calibration (offset + gain) must be re-run after every gain or output-rate change; failure to do so leaves residual offset up to 100 uV at gain = 128.
Place the AD7712AR-REEL7 on a 4-layer PCB with a dedicated analog ground plane beneath the IC and its reference components; route digital traces (SCLK, CS, DOUT, DRDY) on the opposite side or above the ground plane to minimize digital-to-analog crosstalk. Keep the REFIN+/REFIN- traces short and symmetric to avoid thermocouple-induced offset errors; route them differentially with 0.5 mm spacing over the ground plane. The NC pins (16, 17, 18, 21, 22, 23, 24) should be left floating, not grounded - per the datasheet they are not bonded internally.
Thông tin tuân thủ
AD7712AR-REEL7 uses SnPb lead finish and is not RoHS compliant; the ARZ variants (AD7712ARZ-REEL7, AD7712ARZ) are RoHS-compliant drop-in replacements with matte-tin lead plating. Reach and conflict-minerals status typical for legacy ADI AD77xx family parts. AEC-Q100 not applicable - this is an industrial-grade precision converter, not an automotive-qualified part.
