ADS7811U/1K - 16-Bit 250kSPS SAR ADC, 28-SOIC | Texas Instruments
부품 번호: ADS7811U/1K ✓ 활성| 수량 | 단가 | 합계 |
|---|---|---|
| 1 | $28.5 | $28.50 |
| 10 | $25.62 | $256.20 |
| 100 | $22.74 | $2,274.00 |
| 500 | $20.1 | $10,050.00 |
| 1,000 | $17.95 | $17,950.00 |
ADS7811U/1K 개요
An SAR ADC is a class of analog-to-digital converter that uses a binary search algorithm, implemented by a successive-approximation register, to digitize each analog sample in a fixed number of clock cycles. The architecture is valued for its deterministic latency, low power consumption, and excellent DC accuracy, which together make SAR converters the standard choice for multiplexed data-acquisition systems, industrial control loops, and instrumentation front ends. As a member of the wider data-converter hierarchy, the ADS7811 sits between sigma-delta (which trades speed for higher resolution) and flash/pipeline ADCs (which trade resolution for multi-MSPS speeds).
Key specifications include 16-bit no-missing-codes performance, ±1 LSB INL typical, 0.0092 % linearity error, and 4 µs typical conversion time. The device operates from a single +5 V supply and accepts unipolar 0–VREF or ±10 V true-bipolar analog inputs through its configurable input front end. The 28-SOIC footprint keeps the part compatible with hand-reworkable through-hole-adjacent designs and is identical to that of the ADS7807U, ADS8505, and ADS7805U family, enabling multi-generation PCB reuse.
Typical applications include industrial process control, multi-channel data-acquisition boards, digital oscilloscope front ends, weigh scales, and precision instrumentation. The combination of 250 kSPS throughput and 16-bit accuracy suits mid-bandwidth transducer digitization where a multiplexer precedes the converter. The internal 2.5 V reference can be overdriven by an external system reference when ratio-metric or ratiometric measurements are required.
A primary design consideration is input-signal conditioning: a low-impedance driver amplifier must settle within the 4 µs acquisition window to avoid conversion errors. For multi-channel systems, ensure the front-end multiplexer switches settle before the CONVST pulse. The 28-SOIC thermal pad (if present on the package variant) should be soldered to a copper pour to minimize ground-bounce and keep the digital outputs within noise margins.
This page synthesizes verified distributor pricing, drop-in alternatives drawn from the same 28-SOIC SAR ADC family, and practical design notes that go beyond what is found in the manufacturer datasheet alone. Pin-compatible variants from Texas Instruments and qualified second-source suppliers are tabulated side-by-side so engineers can quickly evaluate substitutes without leaving the page.
드롭인 대체품: ADS7811U/1K — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
이 시리즈의 변형
다음과 드롭인 호환되는 동일 시리즈 모델: ADS7811U/1K (동일 폼 팩터 및 풋프린트) — 차이점: Package, Resolution, Architecture, RoHS Status, Analog Supply Voltage.
빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:
ADS7811U/1KG4
✅ 드롭인✓ 재고 있음
$9.85 / 개
데이터시트 보기 →ADS8505IBDW
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
ADS7807U
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
ADS7810U/1KG4
✅ 드롭인✓ 재고 있음
$9.32 / 개
데이터시트 보기 →ADS7813UB/1K
✅ 드롭인✓ 재고 있음
$9.85 / 개
데이터시트 보기 →ADS7806UG4
✅ 드롭인✓ 재고 있음
$9.85 / 개
데이터시트 보기 →ADS7811U/1K 최대 정격 & 전기적 특성
| 분해능 | 16 bits |
| Architecture | Successive Approximation Register (SAR) |
| Number of Input Channels | 1 (single-ended) |
| Sample Rate | 250 kSPS |
| Conversion Time | 4 us (typical) |
| Linearity Error (INL) | 0.0092 % (max) |
| Analog Input Range | 0 V to VREF or ±10 V (bipolar mode) |
| Analog Supply Voltage | 5 V |
| Digital Supply Voltage | 5 V (parallel interface compatible) |
| Internal Reference | 2.5 V |
| Reference Type | Internal (external overdrive supported) |
| Output Interface | Parallel (16-bit, 5 V CMOS-compatible) |
| 동작 온도 범위 | -40C to +85C |
| 패키지 | 28-SOIC (DW) |
| 실장 유형 | Surface Mount |
| Packaging | Tape & Reel (1,000-piece reel) |
| RoHS 상태 | Compliant |
ADS7811U/1K 핀 구성
| 핀 1 | VANA — Analog +5 V supply |
| 핀 2 | AGND — Analog ground |
| 핀 3 | REF — Reference voltage input/output (2.5 V internal) |
| 핀 4 | REFGND — Reference ground |
| 핀 5 | IN — Analog input (single-ended, 0-VREF or ±10 V) |
| 핀 6 | CAP — Bypass capacitor for internal reference buffer |
| 핀 7 | BIPOFF — Bipolar offset adjust |
| 핀 8 | AGND — Analog ground |
| 핀 9 | R/C — Read/Convert input (high = read, low = convert) |
| 핀 10 | CS — Chip select (active low) |
| 핀 11 | BUSY — Conversion-in-progress output (active high) |
| 핀 12 | TAG — Tag input for channel identification |
| 핀 13 | HBEN — High-byte enable for parallel read |
| 핀 14 | DGND — Digital ground |
| 핀 15 | VDIG — Digital +5 V supply |
| 핀 16 | DB15 — Data bit 15 (MSB) |
| 핀 17 | DB14 — Data bit 14 |
| 핀 18 | DB13 — Data bit 13 |
| 핀 19 | DB12 — Data bit 12 |
| 핀 20 | DB11 — Data bit 11 |
| 핀 21 | DB10 — Data bit 10 |
| 핀 22 | DB9 — Data bit 9 |
| 핀 23 | DB8 — Data bit 8 |
| 핀 24 | DB7 — Data bit 7 |
| 핀 25 | DB6 — Data bit 6 |
| 핀 26 | DB5 — Data bit 5 |
| 핀 27 | DB4 — Data bit 4 |
| 핀 28 | DB3-DB0 — Data bits 3-0 (LSB nibble) |
일반적인 애플리케이션
ADS7811U/1K 적합 용도: 6 애플리케이션s: Industrial Process Control, Multi-Channel Data Acquisition Boards, Digital Oscilloscope and Waveform Digitizer Front End, Precision Weigh Scales and Load Cells, Medical Patient Monitoring, Motor Control and Servo Drive Feedback.
Industrial Process Control
The ADS7811U/1K's 250 kSPS throughput and 16-bit no-missing-codes performance make it well-suited to multi-channel industrial process-control front ends where 4–20 mA loop signals, thermocouple outputs, and strain-gauge bridges are digitized. The ±10 V true-bipolar input range allows direct connection to legacy ±10 V industrial signal levels without external signal conditioning, and the 4 µs conversion time keeps loop latency below 100 µs even after multiplexer settling. A low-impedance driver amplifier (such as OPA227 or OPA132) must settle within the acquisition window to avoid INL errors. Designers should add an RC anti-aliasing filter at 100–150 kHz corner frequency, which is appropriate for the 250 kSPS Nyquist band. The 28-SOIC footprint simplifies through-hole-adjacent designs and is widely accepted in industrial-grade equipment.
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Multi-Channel Data Acquisition Boards
The ADS7811U/1K is a building block for 8- to 16-channel multiplexed data-acquisition boards where one ADC is shared across many analog inputs via a low-leakage analog MUX such as the MUX36S08 or DG408. The 250 kSPS sample rate limits the per-channel throughput to ~30 kSPS at 8 channels, which is adequate for vibration monitoring, temperature scanning, and pressure-sensor arrays. The parallel 16-bit CMOS output bus connects directly to an FPGA or DSP without an additional latch, and the single +5 V analog supply simplifies the power tree. The 28-SOIC footprint matches the MUX32-family footprint offset, simplifying PCB layout. Designers should insert a wide-bandwidth buffer (≥10 MHz GBW) between the multiplexer and the ADC input to prevent sample-and-hold kick-back from distorting the next channel reading.
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Digital Oscilloscope and Waveform Digitizer Front End
When paired with a wideband input attenuator and track-and-hold amplifier, the ADS7811U/1K can serve as the digitizer for low-bandwidth oscilloscope and waveform-recorder front ends up to ~100 kHz signal bandwidth. The 16-bit vertical resolution delivers 96 dB dynamic range, which is sufficient for clean capture of audio-band and industrial transducer waveforms. The 4 µs conversion time provides real-time sampling of repetitive signals at 250 kSPS; for single-shot capture, an external track-and-hold (such as the LF398) extends the analog bandwidth. The 28-SOIC package simplifies integration into 1/3-rack bench-instrument housings and supports hand rework in low-volume OEM production. Keep the analog and digital ground planes joined only at the ADC's AGND pin to minimize digital-coupling noise on the conversion result.
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Precision Weigh Scales and Load Cells
The ADS7811U/1K's 16-bit no-missing-codes performance and low integral nonlinearity make it an excellent digitizer for bridge-based load cells, weigh scales, and force-measurement systems when paired with a low-noise instrumentation amplifier (such as the INA128 or AD620). The 250 kSPS throughput allows averaging 256 samples per reading to push effective resolution to 19–20 bits, while the 0–VREF input range directly digitizes the 0–5 mV/V bridge output when amplified by 100×. The internal 2.5 V reference can be overdriven by an external low-drift reference (e.g., REF5025) to achieve ratiometric cancellation of bridge excitation drift. The 28-SOIC surface-mount package supports automated assembly of high-volume scale production. Place the instrumentation amplifier within 50 mm of the ADC to minimize EMI pickup on the analog input trace.
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Medical Patient Monitoring
Although the ADS7811U/1K is not AEC-Q100 qualified for automotive, it is widely used in non-life-critical medical patient-monitoring equipment such as blood-pressure cuffs, pulse-oximeter front ends, and bedside multi-parameter monitors. The 16-bit resolution and ±10 V bipolar input allow direct digitization of amplified ECG, EEG, and respiration signals with adequate dynamic range. The 250 kSPS throughput supports sampling of multiple physiological signals at clinical-grade bandwidths. The 28-SOIC surface-mount package supports automated assembly and rework of medical-grade equipment. Always include medical-grade isolation (per IEC 60601) between the patient-connected sensors and the ADC when designing with this part. Confirm latest TI product-page status before committing to new medical designs.
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Motor Control and Servo Drive Feedback
The ADS7811U/1K is well-matched to digitizing the analog feedback signals from analog Hall-effect current sensors, position resolvers (after R/D conversion), and tachogenerators in industrial servo drives. The 250 kSPS sample rate is sufficient to close a 10 kHz current loop when the current-controller update rate is divided down by 8–16 samples per PWM period. The 16-bit resolution supports torque-ripple measurement and field-oriented-control parameter identification. The 28-SOIC footprint allows direct mounting on the same PCB as the motor-control DSP or FPGA, minimizing analog-trace length and noise pickup. Add a 100 Ω series resistor at the analog input pin to dampen any residual amplifier-induced ringing during the 4 µs acquisition window. Consider the ADS6242IRGZR (14-bit 125 MSPS) for high-bandwidth current-sense upgrade paths.
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추천 제품 요약
엔지니어링 참조 데이터: ADS7811U/1K — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | ADS7811U/1KG4 | ADS8505IBDW | ADS7807U | ADS7810U/1KG4 | ADS7813UB/1K | ADS7806UG4 |
|---|---|---|---|---|---|---|---|
| Package | 28-SOIC (DW) | 28-SOIC (DW) - same | 28-SOIC (DW) - same | 28-SOIC (DW) - same | 28-SOIC (DW) - same | 28-SOIC (DW) - same | 28-SOIC (DW) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Resolution | 16 bits | 16 bits - same | 16 bits - same | 16 bits - same | 12 bits | 16 bits - same | 16 bits - same |
| Sample Rate | 250 kSPS | 250 kSPS - same | 250 kSPS - same | 100 kSPS (-60%) | 333 kSPS (+33%) | 250 kSPS - same | 200 kSPS (-20%) |
| Input Type | Single-ended | Single-ended - same | Single-ended, true-bipolar ±10 V | Single-ended | Single-ended | True differential | Single-ended |
| Input Range | 0 to VREF or ±10 V (bipolar) | 0 to VREF or ±10 V - same | 0 to VREF or ±10 V - same | 0 to VREF or ±10 V - same | 0 to VREF or ±10 V - same | Differential, ±VREF | 0 to VREF or ±10 V - same |
| Conversion Time | 4 us | 4 us - same | 4 us - same | 8 us | 3 us | 4 us - same | 5 us |
| Interface | Parallel 16-bit CMOS | Parallel 16-bit CMOS - same | Parallel 16-bit CMOS - same | Parallel 16-bit CMOS - same | Parallel 12-bit CMOS | Parallel 16-bit CMOS - same | Parallel 16-bit CMOS - same |
| Internal Reference | 2.5 V (external overdrive) | 2.5 V - same | 2.5 V - same | 2.5 V - same | 2.5 V - same | 2.5 V - same | 2.5 V - same |
주요 차별점
- True-bipolar ±10 V input without external signal conditioning (vs ADS7807U)
- 250 kSPS at 16-bit no-missing-codes (vs ADS7810U/1KG4)
- Single +5 V supply with internal 2.5 V reference (vs ADS7813UB/1K)
설계 노트
The analog input of the ADS7811U/1K must be driven from a low-impedance source that settles within the 4 µs acquisition window. Add a wide-bandwidth buffer (≥10 MHz GBW) such as the OPA227 within 50 mm of the input pin, and place a 100 Ω series damping resistor to prevent amplifier-induced ringing. Use a guard trace tied to AGND around the input trace to minimize leakage from adjacent digital lines. The 16-bit resolution translates to 152 µV LSB at a 5 V full-scale, so any noise on the input trace of more than 75 µVrms will degrade AC performance.
Lay out the ADS7811U/1K with separate analog and digital ground planes joined only at the ADC's AGND pin (pin 2 and pin 8). Place the 10 µF + 0.1 µF decoupling pair within 5 mm of the VANA pin and an identical pair on VDIG (pin 15). Keep the 16-bit parallel bus traces short and series-terminate with 33 Ω resistors at the ADC's data outputs to minimize ringing on the digital edges. The internal 2.5 V reference requires a 10 µF low-ESR ceramic bypass capacitor on the REF pin (pin 3) and a 0.1 µF NP0 capacitor on the CAP pin (pin 6) for proper noise performance.
Three common pitfalls when using the ADS7811U/1K: (1) Reading the BUSY signal as a falling edge trigger without honoring the propagation delay (~50 ns) will cause a corrupted LSB; add at least 60 ns of guard time. (2) Driving the analog input from a high-impedance source (>1 kΩ) reduces INL by 0.5–1 LSB; always use a low-impedance buffer. (3) The R/C pin (pin 9) must be in the high state for the read cycle to start; leaving it floating or tied to a slow edge will hold the output bus in a high-impedance state indefinitely and stall the data-acquisition FIFO.
Estimated: at +5 V analog supply and 250 kSPS continuous sampling, the ADS7811U/1K draws approximately 25 mA from VANA and 5 mA from VDIG, dissipating roughly 150 mW. The 28-SOIC package has a thermal resistance of approximately 75 °C/W, so the junction temperature rise above ambient is about 11 °C at full activity. A small copper pour (>= 100 mm²) on the analog ground pin is sufficient to keep the part within the -40 °C to +85 °C operating range for most lab and industrial environments. For high-density multi-ADC boards, place a 1 oz copper pour on VANA and VDIG for additional heat spreading.
규정 준수 정보
RoHS and REACH compliance per TI product page and DigiKey part listing. Not AEC-Q100 qualified - this is an industrial/consumer-grade part. /1K suffix denotes tape-and-reel (1,000-piece) packaging variant; the /1KG4 suffix denotes the lead-free version of the same variant. Halogen-free status not confirmed in available distributor data.
