AD977ABR - 16-Bit 200kSPS Serial SAR ADC | 20-SOIC | ADI
Артикул: AD977ABR ✓ Активен| Кол-во | Цена за ед. | Итого |
|---|---|---|
| 1 | $24.5 | $24,50 |
| 10 | $21.95 | $219,50 |
| 100 | $19.1 | $1.910,00 |
| 500 | $16.85 | $8.425,00 |
| 1.000 | $14.5 | $14.500,00 |
AD977ABR Обзор
An ADC (analog-to-digital converter) is a data-converter integrated circuit that samples a continuous analog input voltage and produces a corresponding digital code at its output. SAR ADCs use a binary-search successive-approximation register together with an internal DAC to resolve each conversion in N clock cycles for N-bit precision; they are valued for zero pipeline latency, deterministic behavior, low power, and excellent DC linearity. SAR converters occupy a unique position in the data-converter hierarchy between high-speed flash/pipeline ADCs (>10 MSPS) and slow integrating/sigma-delta ADCs (audio, precision DC). The AD977A family is one of the classic low-power industrial SAR ADCs of the 1990s and remains in production for installed-base applications.
Key features include an aperture delay of 5 ns, track-and-hold bandwidth of 2 MHz, and a power-down mode that reduces quiescent dissipation to 50 µW for battery-powered designs. The serial interface is compatible with standard SPI/QSPI/MICROWIRE hosts, simplifying connection to microcontrollers and DSPs. Input protection diodes are absent on the analog input pin, so external clamping is required when the input can exceed the supply rails.
Typical applications include industrial process control data acquisition, multichannel PLC analog input modules, portable instrumentation, weighing scales, and remote sensor digitizers. The combination of ±5 V true-bipolar input range and serial output makes the part especially well suited to legacy PLCs and 4-20 mA loop digitizers. Designers should observe the datasheet's reference decoupling and analog-input filtering guidelines to realize the rated INL/DNL and signal-to-noise ratio, and should add an external TVS/Schottky clamp at the analog input when transients beyond ±5 V are possible.
Аналоги без доработки для AD977ABR — тот же корпус, pin-to-pin совместимость. Компоненты в других корпусах, требующие переработки PCB, исключены.
Варианты в этой серии
Модели той же серии, совместимые без доработки с AD977ABR (тот же форм-фактор и посадочное место) — отличается по Architecture, Resolution, Data Interface, No Missing Codes, Number of Channels.
Инструмент быстрого сравнения — выберите альтернативные компоненты для сравнения бок о бок:
AD977AR
✅ Прямая замена ⚠️ Характеристики не проверены📋 Справочный аналог (нет в каталоге)
AD977ABRZ
✅ Прямая замена ⚠️ Характеристики не проверены📋 Справочный аналог (нет в каталоге)
AD977ACRZ
✅ Прямая замена ⚠️ Характеристики не проверены📋 Справочный аналог (нет в каталоге)
AD977ABR-REEL
✅ Прямая замена ⚠️ Характеристики не проверены📋 Справочный аналог (нет в каталоге)
AD7674ACPZRL
✅ Прямая замена✓ В наличии
$38.95 / шт.
Открыть даташит →AD977ABR Максимальные параметры и электрические характеристики
| Разрешение | 16 bit |
| Architecture | Successive Approximation (SAR) |
| Number of Channels | 1 |
| Throughput Rate | 200 kSPS |
| Напряжение питания | +5 V single |
| Power Dissipation (max) | 100 mW |
| Power-Down Mode Current | 50 µW (typical) |
| Input Ranges (unipolar) | 0 V to 5 V; 0 V to 4 V |
| Input Ranges (bipolar) | ±5 V; ±3.3 V |
| Digital Interface | Serial (SPI/QSPI/MICROWIRE-compatible) |
| Aperture Delay | 5 ns |
| Track-and-Hold Bandwidth | 2 MHz |
| Корпус | 20-pin SOIC (R-20), wide-body |
| Диапазон рабочих температур | -40 °C to +85 °C (industrial) |
| Тип монтажа | Surface Mount |
| Lead-Free / RoHS | Compliant |
Конфигурация выводов AD977ABR
| Контакт 1 | VREF — Internal reference voltage output (decoupling cap) |
| Контакт 2 | R1IN — Input range setting resistor 1 node |
| Контакт 3 | R2IN — Input range setting resistor 2 node |
| Контакт 4 | AIN — Analog input |
| Контакт 5 | AGND — Analog ground (sense) |
| Контакт 6 | AGND — Analog ground (force) |
| Контакт 7 | CAL — Calibration enable / mode select |
| Контакт 8 | PD — Power-down input (active high) |
| Контакт 9 | RESET — Reset input |
| Контакт 10 | AVDD — +5 V analog supply |
| Контакт 11 | AVDD — +5 V analog supply |
| Контакт 12 | SCLK — Serial clock input |
| Контакт 13 | SDOUT — Serial data output |
| Контакт 14 | DVDD — +5 V (or +3 V) digital supply |
| Контакт 15 | DGND — Digital ground |
| Контакт 16 | TAG — Tag input for data tagging |
| Контакт 17 | CONVST — Conversion start input |
| Контакт 18 | CS — Chip select (active low) |
| Контакт 19 | BUSY — Conversion busy output (active high) |
| Контакт 20 | DRDY — Data ready output |
Типичное применение
AD977ABR подходит для 6 применениеs: Industrial Process Control / PLC Analog Input Modules, Multichannel Data Acquisition Boards, Portable Battery-Powered Instrumentation, Weigh Scale and Force Measurement Systems, Remote Sensor and Telemetry Digitizers, Medical and Analytical Instrumentation Front Ends.
Industrial Process Control / PLC Analog Input Modules
The AD977ABR's 16-bit resolution and ±5 V true-bipolar input range make it a natural fit for industrial PLC analog input modules digitizing 4-20 mA loops and ±10 V transducer outputs. With a single +5 V supply, 100 mW dissipation, and serial SPI-compatible output, the part drops directly onto a 4-channel PLC backplane. Compared with a sigma-delta alternative, the SAR architecture provides zero pipeline latency and deterministic conversion time, which is critical for closed-loop control. Throughput of 200 kSPS supports oversampling to suppress 50/60 Hz mains pickup while preserving bandwidth for fast process variables.
Рекомендуется
Multichannel Data Acquisition Boards
The AD977ABR is ideal for low-cost multichannel data-acquisition boards where a serial ADC simplifies board routing and reduces microcontroller pin count. Up to eight AD977ABR devices can share a single SPI bus via individual CS lines, yielding 8 channels of 16-bit data at 200 kSPS aggregate. The 2 MHz track-and-hold bandwidth preserves signal integrity on multiplexed inputs above the per-channel Nyquist rate. Designers typically add an input multiplexer (e.g., ADG708) plus an instrumentation amp front end (AD620) to build a 16-channel 16-bit DAS on a single 5 V rail.
Рекомендуется
Portable Battery-Powered Instrumentation
The AD977ABR's hardware power-down mode drops dissipation to 50 µW, making it suitable for battery-powered handheld instruments such as digital multimeters, handheld oscilloscope probes, and field calibrators. A single +5 V rail simplifies power architecture - typically a boost converter from a 3.6 V Li-ion cell. The 200 kSPS throughput enables accurate True-RMS and harmonic-distortion measurements on AC waveforms, while the SOIC-20 wide-body package provides good thermal margin for extended 4-wire Kelvin measurements in the field.
Рекомендуется
Weigh Scale and Force Measurement Systems
Weigh scales and load-cell digitizers benefit from the AD977ABR's 16-bit no-missing-codes performance and ±3.3 V or ±5 V bipolar input range that directly accommodates load-cell bridge outputs. The SAR architecture's excellent DC linearity (low INL/DNL) preserves calibration accuracy across the full scale range, while the serial output simplifies isolated data transfer across the bridge excitation barrier. A typical implementation pairs the AD977ABR with an AD8421 instrumentation amp and a low-drift reference such as the ADR01.
Рекомендуется
Remote Sensor and Telemetry Digitizers
Remote sensor digitizers in SCADA, weather stations, and pipeline monitoring benefit from the AD977ABR's single +5 V supply, low power, and serial interface that minimizes cabling to a host microcontroller. The 50 µW power-down current lets the host duty-cycle the ADC for very low average power in solar-powered remote installations. With 200 kSPS capability the part oversamples to suppress noise while keeping duty cycle low. Analog Devices' ADuC847 family of microcontrollers is a popular host, providing integrated references and excitation for the loop.
Рекомендуется
Medical and Analytical Instrumentation Front Ends
Bench-top medical analyzers (chemistry, hematology, immunoassay) and environmental monitors use the AD977ABR to digitize photodiode, conductivity, and ion-selective-electrode signals with 16-bit precision. The part's low integral nonlinearity preserves calibration curves over the full-scale range, while the serial output connects directly to the analyzer's embedded controller. Pairing the AD977ABR with the AD8628 chopper-stabilized op-amp achieves sub-LSB noise levels suitable for clinical-grade measurements.
Рекомендуется
Сводка рекомендуемых товаров
Справочные инженерные данные для AD977ABR — сравнение, рекомендации по проектированию и информация о соответствии.
Руководство по выбору
Сравнение с аналогами
| Параметр | Этот товар | AD977AR | AD977ABRZ | AD977ACRZ | AD7674ACPZRL |
|---|---|---|---|---|---|
| Package | SOIC-20 (R-20) | SOIC-20 (R-20) - same | SOIC-20 (R-20) - same | SOIC-20 (R-20) - same | LFCSP-48 - different |
| Brand | Analog Devices | Analog Devices - same | Analog Devices - same | Analog Devices - same | Analog Devices - same |
| Resolution | 16 bit | 16 bit | 16 bit | 16 bit | 16 bit |
| Throughput | 200 kSPS | 100 kSPS (-50%) | 200 kSPS (same) | 200 kSPS (same) | 800 kSPS (+300%) |
| Architecture | SAR (single-channel) | SAR (single-channel) | SAR (single-channel) | SAR (single-channel) | SAR (single-channel) |
| Supply Voltage | +5 V single | +5 V single | +5 V single | +5 V single | +5 V single |
| Power Dissipation | 100 mW max | 100 mW max | 100 mW max | 100 mW max | 110 mW max (+10%) |
| Input Range (max bipolar) | ±5 V true bipolar | ±5 V true bipolar | ±5 V true bipolar | ±5 V true bipolar | ±5 V true bipolar |
| Digital Interface | Serial (SPI/QSPI/MICROWIRE) | Serial (SPI/QSPI/MICROWIRE) | Serial (SPI/QSPI/MICROWIRE) | Serial (SPI/QSPI/MICROWIRE) | Parallel / Serial selectable |
| Lead-Free / RoHS | Compliant | Non-compliant (matte-tin) | Compliant | Compliant | Compliant |
Ключевые отличия
- 200 kSPS in true ±5 V bipolar input - rare for legacy SAR ADC family (против AD977AR)
- Modern lead-free / RoHS-compliant packaging option in same SOIC-20 (против AD977ABR (matte-tin))
- Zero pipeline latency SAR architecture for closed-loop control (против AD7674ACPZRL)
Заметки по проектированию
Estimated: at +5 V supply and 200 kSPS continuous conversion, average supply current is approximately 20 mA per datasheet, yielding about 100 mW dissipation. Add a 10 µF tantalum + 0.1 µF ceramic decoupling pair close to each AVDD/DVDD pin pair. Tie the analog and digital ground planes together at one point under the IC body to avoid ground-loop noise coupling through the reference. Use the hardware PD (pin 8) to drop standby dissipation to 50 µW in battery-powered designs.
The analog input pin has NO internal ESD protection diodes to the supply rails. Apply an external BAT54S Schottky clamp or TVS to AGND and AVDD when the input can exceed ±5 V (e.g. from transients on a long sensor cable). Without this clamp, an input transient above AVDD or below AGND will forward-bias the ESD structure and may permanently damage the ADC. This is the single most common field issue documented in the AD977A errata.
Place the input range-setting resistors (R1, R2 between pins 2, 3 and AVDD/AGND) within 5 mm of the package, and add a 1 nF ceramic across AIN to AGND right at the pin. The 2 MHz track-and-hold bandwidth requires a low-impedance input driver - a series resistor between the op-amp output and AIN greater than 1 kΩ will cause conversion errors due to ADC input kick-back. Use an op-amp such as AD8628 or AD797 with adequate current drive to settle the ADC input within the acquisition window.
Route the serial interface lines (SCLK, SDOUT, CONVST, CS) away from the analog input trace and the reference decoupling node. Keep the analog input trace length below 25 mm and surround it with a ground pour tied to AGND only. Place the 22 µF VREF bypass cap as close as possible to pin 1. According to the AD977A datasheet layout recommendations, the AGND plane should extend under the entire ADC body to provide a low-impedance return path for the reference and analog input currents.
Информация о соответствии
Per the Vyrian product listing (2026-10-12), AD977ABR ships with lead-free/RoHS-compliant terminal finish. AEC-Q100 automotive grade is not qualified; for automotive designs consider the AD7862ARS or AD7899AR-3REEL family members which offer extended temperature variants.
