ADS8887 - 18-Bit 100kSPS True-Differential SAR ADC | TI
부품 번호: ADS8887 ✓ 활성| 수량 | 단가 | 합계 |
|---|---|---|
| 1 | $6.2 | $6.20 |
| 10 | $5.58 | $55.80 |
| 100 | $4.96 | $496.00 |
| 500 | $4.46 | $2,230.00 |
| 1,000 | $3.97 | $3,970.00 |
ADS8887 개요
A SAR ADC is a type of analog-to-digital converter that uses a binary search algorithm to convert an analog input into a digital output, consisting of a comparator, a capacitive DAC, and successive approximation logic. SAR ADCs, a subset of data converters in mixed-signal electronics, are known for high speed, low power, and excellent accuracy in data acquisition, industrial process control, and medical instrumentation.
Key features include 18-bit resolution, a 100 kSPS maximum sampling rate, and a true-differential input that rejects common-mode noise. The device runs from a single 2.7-V to 3.6-V analog supply with a separate digital supply for the serial interface. An external reference between 2.5 V and 5 V lets designers optimize the input range per application. A power-down mode reduces current to microamperes, suiting battery-powered systems.
Technically, the ADS8887 uses a charge-redistribution SAR architecture with a capacitive DAC, achieving INL of ±1 LSB and SNR of 100 dB. An internal oscillator and track-and-hold circuit reduce external component count. The SPI-compatible serial interface supports 3-wire and 4-wire modes and daisy-chaining for multi-channel systems; the 10 MHz input bandwidth accurately samples high-frequency signals.
Typical applications include precision data acquisition, industrial automation, medical imaging, and portable instrumentation. The true-differential input makes it ideal for bridge sensors, thermocouples, and other differential signal sources, plus battery-powered data loggers and IoT devices.
Design tip: provide a low-impedance reference source, bypass the reference with a 10-uF capacitor, and drive the analog input from a low-impedance source such as an op amp to achieve full datasheet performance.
드롭인 대체품: ADS8887 — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:
ADS8866IDGSR
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
ADS8885IDGSR
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
ADS8881IDGSR
✅ 드롭인 ⚠️ 사양 미검증📋 참조 대체품 (카탈로그에 없음)
ADS8860IDGSR
✅ 드롭인 ⚠️ 사양 미검증📋 참조 대체품 (카탈로그에 없음)
AD7920
⚡ 동일 패키지 ⚠️ 사양 미검증📋 참조 대체품 (카탈로그에 없음)
ADS8887 최대 정격 & 전기적 특성
| 분해능 | 18 bit |
| 샘플링 속도 | 100 kSPS |
| Input Type | True-differential, 1 channel |
| Reference Voltage Range | 2.5 V to 5 V (external) |
| Analog Supply (AVDD) | 2.7 V to 3.6 V |
| 인터페이스 | SPI-compatible serial (3-wire/4-wire, daisy-chain) |
| SNR | 100 dB |
| INL | ±1 LSB |
| Input Bandwidth | 10 MHz |
| Architecture | SAR, charge redistribution with capacitive DAC |
| 동작 온도 | -40C to +85C (I grade) |
| 패키지 | 10-VSSOP (DGS) |
| 실장 유형 | Surface Mount |
| RoHS 상태 | Compliant |
ADS8887 핀 구성
| 핀 1 | IN+ — Non-inverting differential analog input |
| 핀 2 | IN- — Inverting differential analog input |
| 핀 3 | GND — Ground reference |
| 핀 4 | REF — External reference input, 2.5 V to 5 V |
| 핀 5 | CONVST — Conversion start control |
| 핀 6 | DVDD — Digital interface supply |
| 핀 7 | SCLK — Serial clock input |
| 핀 8 | DIN — Serial data input (command register) |
| 핀 9 | DOUT/RDY — Serial data output / ready indicator |
| 핀 10 | AVDD — Analog supply, 2.7 V to 3.6 V |
일반적인 애플리케이션
ADS8887 적합 용도: 6 애플리케이션s: Precision Data Acquisition, Industrial Process Control, Medical Instrumentation, Portable and Battery-Powered Instruments, IoT Sensor Nodes, Automated Test and Measurement.
Precision Data Acquisition
The ADS8887 fits precision DAQ front ends where its 18-bit resolution, 100 dB SNR, and ±1 LSB INL resolve microvolt-level signals. The true-differential input rejects common-mode noise from industrial environments, and the 100-kSPS rate captures fast transients. Placed after an op-amp driver with 10-uF reference bypass, it digitizes multi-channel sensor arrays via SPI daisy-chaining without adding switching noise.
추천
Industrial Process Control
In factory automation and process control, the ADS8887 digitizes 4-20 mA loops, bridge transducers, and pressure sensors with 18-bit accuracy. Its 2.5-V to 5-V external reference allows signal-range optimization without scaling circuitry, while the differential input suppresses motor and relay common-mode noise. Power-down mode between conversions lowers system power in always-on monitoring nodes.
추천
Medical Instrumentation
Medical diagnostic equipment benefits from the ADS8887's 100 dB SNR and low-noise differential input, which preserve small biosignals such as ECG and impedance-measurement channels. The miniature 10-VSSOP package conserves board space in portable and handheld devices, and the internal oscillator removes an external clock source, reducing component count in size-constrained medical designs.
추천
Portable and Battery-Powered Instruments
For handheld meters and field instruments, the ADS8887's microampere power-down current extends battery life dramatically: the ADC wakes on CONVST, converts at 100 kSPS, and returns to shutdown. Its 2.7-V to 3.6-V single analog supply runs directly from Li-ion or two-cell stacks, and the tiny 10-VSSOP footprint fits compact enclosures typical of portable test gear.
추천
IoT Sensor Nodes
IoT edge nodes use the ADS8887 to digitize thermocouples, RTDs, and bridge sensors with 18-bit resolution while minimizing energy per sample. SPI-compatible 3-wire and daisy-chain modes let one MCU bus serve multiple converters, and the internal oscillator saves board area. Combined with a low-power MCU and buck regulator, duty-cycled sampling keeps average current in the microamp range.
추천
Automated Test and Measurement
Bench instruments and automated test equipment exploit the ADS8887's 10 MHz input bandwidth and 100-kSPS throughput to sample wideband signals accurately. The true-differential input maintains dynamic range when measuring grounded or floating sources, and ±1 LSB INL guarantees monotonic, repeatable readings. Daisy-chain SPI simplifies scaling from one channel to multi-channel arrays in modular ATE.
추천
추천 제품 요약
엔지니어링 참조 데이터: ADS8887 — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | ADS8866IDGSR | ADS8885IDGSR | ADS8881IDGSR | ADS8860IDGSR |
|---|---|---|---|---|---|
| Package | 10-VSSOP (DGS) | 10-VSSOP (DGS) - same | 10-VSSOP (DGS) - same | 10-VSSOP (DGS) - same | 10-VSSOP (DGS) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Resolution | 18 bit | 16 bit | 16 bit | 18 bit | 16 bit |
| Input Type | True-differential | Pseudo-differential | True-differential | True-differential | Pseudo-differential |
| Reference Range | 2.5 V to 5 V | 2.5 V to 5 V | 2.5 V to 5 V | 2.5 V to 5 V | 2.5 V to 5 V |
| Interface | SPI (3/4-wire, daisy-chain) | SPI (3/4-wire, daisy-chain) | SPI (3/4-wire, daisy-chain) | SPI (3/4-wire, daisy-chain) | SPI (3/4-wire, daisy-chain) |
주요 차별점
- 18-bit resolution at 100 kSPS (vs ADS8866IDGSR)
- True-differential input (vs ADS8866IDGSR)
- Family software compatibility (vs ADS8885IDGSR)
설계 노트
Provide a low-impedance reference source and bypass the REF pin with a 10-uF capacitor close to the pin, per the ADS8887 datasheet typical application circuit. Separate analog ground and digital return paths, joining them at a single star point under the converter. Keep the SPI clock lines away from IN+/IN- traces to avoid digital coupling into the analog front end during acquisition.
The SAR capacitive DAC injects charge kickback onto IN+ and IN- at the start of each acquisition. Drive both differential inputs from a low-impedance source such as an op amp (for example OPA2375 or OPA2192) with an RC filter sized so the inputs settle within the acquisition window; otherwise SNR degrades below the specified 100 dB and INL errors appear near code transitions.
Decouple AVDD (2.7 V to 3.6 V) and DVDD each with 0.1-uF ceramics placed within 2 mm of the pins. Remember the REF voltage may exceed AVDD - reference integrity, not AVDD, sets the full-scale range. Use the CONVST-controlled power-down mode between conversions in battery designs to keep average current in the microampere range.
규정 준수 정보
RoHS compliant per TI product page and distributor listings.
