ADS8900B - 20-Bit 1-MSPS SAR ADC with Ref Buffer | TI
MPN： ADS8900B ✓ 啟用中ADS8900B 概覽
A SAR ADC converts an analog input to a digital output using a binary search algorithm with a capacitive DAC and precision comparator. SAR converters occupy a key position in the data acquisition signal chain, balancing speed, resolution, and power for microcontroller and DSP-based systems.
Key features include 1-MSPS sampling at 20-bit resolution, ±1 ppm integral nonlinearity (INL), and 104.5 dB SNR under typical conditions. The device supports unipolar, fully differential, and pseudo-differential analog inputs. The integrated reference buffer eliminates the need for a high-bandwidth external reference buffer, and the integrated LDO enables simplified power tree design. The SPI-compatible serial interface supports daisy-chain and multi-device configurations.
The ADS8900B uses a high-speed capacitive-DAC SAR architecture achieving excellent linearity and low noise. Typical power consumption is approximately 15 mW at 1 MSPS from a 3.3V analog supply and 1.8V digital supply, suiting space-constrained precision designs.
Typical applications include industrial automation and process control, power quality monitoring, medical instrumentation, and automated test equipment, where the ±1 ppm INL and 104.5 dB SNR directly improve measurement accuracy.
Design consideration: decouple analog and digital supplies thoroughly and evaluate the integrated LDO-generated reference versus a low-noise external reference such as the REF5030A for the highest-accuracy systems.
直接替換替代品，適用於 ADS8900B — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： ADS8900B （相同外形與佔位） — 差異在於 Architecture, Package, Resolution.
ADS8902B
✅ 直接替換📋 參考替代品（不在目錄中）
ADS8904B
✅ 直接替換📋 參考替代品（不在目錄中）
ADS8910B
✅ 直接替換📋 參考替代品（不在目錄中）
ADS8920B
✅ 直接替換📋 參考替代品（不在目錄中）
AD7980ARMZ
✅ 直接替換 ⚠️ 規格未經驗證聯絡詢價
查看資料表 →ADS8900B 最大額定值與電氣特性
| 解析度 | 20 bit |
| 取樣率 | 1 MSPS |
| Number of Channels | 1 |
| Architecture | SAR (capacitive DAC) |
| INL | ±1 ppm (typical) |
| SNR | 104.5 dB (typical) |
| Analog Input Type | Unipolar, fully differential, pseudo-differential |
| Reference Buffer | Integrated |
| Integrated LDO | Yes |
| 介面 | SPI-compatible serial, daisy-chain capable |
| Analog Supply | 3.3 V |
| Digital Supply | 1.8 V |
| Power Consumption | Approx. 15 mW at 1 MSPS (typical) |
| 封裝 | VQFN-20 (RGE) |
| 安裝類型 | Surface Mount |
| RoHS 狀態 | Compliant |
ADS8900B 腳位配置
| 腳位 1 | REFM — Reference buffer output / reference decoupling [DATA_NEEDED: confirm per datasheet] |
| 腳位 2 | REFT — Reference decoupling [DATA_NEEDED: confirm per datasheet] |
| 腳位 3 | INP — Positive analog input |
| 腳位 4 | INN — Negative analog input |
| 腳位 5 | AVDD — 3.3V analog supply |
| 腳位 6 | GND — Ground |
| 腳位 7 | CAP — Integrated LDO output capacitor |
| 腳位 8 | DVDD — 1.8V digital supply |
| 腳位 9 | SCLK — Serial clock input |
| 腳位 10 | SDI — Serial data input |
| 腳位 11 | SDO — Serial data output |
| 腳位 12 | CS — Chip select |
| 腳位 13 | CONVST — Conversion start |
| 腳位 14 | BUSY — Conversion busy indicator |
| 腳位 15 | PD — Power down control |
典型應用
ADS8900B 適用於 6 應用s: Industrial Automation and Process Control, Power Quality Monitoring, Medical Instrumentation, Automated Test Equipment (ATE), Data Acquisition (DAQ) Systems, Vibration and Acoustic Analysis.
Industrial Automation and Process Control
The ADS8900B's ±1 ppm INL and 104.5 dB SNR provide the measurement accuracy demanded by precision process-control loops and factory instrumentation. Sampling at 1 MSPS captures fast transients in sensor front ends for pressure, flow, and temperature bridges. Its SPI interface connects directly to TI C2000 or MSP430 MCUs, and the integrated reference buffer and LDO simplify the analog power tree in crowded industrial control boards.
推薦
Power Quality Monitoring
In power quality analyzers and smart grid metering, the ADS8900B digitizes voltage and current channels with 20-bit resolution, resolving small harmonic components against large fundamental signals thanks to 104.5 dB SNR. The 1-MSPS rate supports transient capture per IEC-class monitoring, and its pseudo-differential input accommodates single-ended sensor outputs. Integrated reference buffering removes reference-buffer design risk in multichannel racks.
推薦
Medical Instrumentation
Diagnostic and analytical medical instruments benefit from the ADS8900B's 20-bit resolution and ±1 ppm linearity, which preserve weak biosignal detail from photodiodes, pressure sensors, and chemical front ends. At 1 MSPS it supports both slow physiological waveforms and fast optical/ultrasonic bursts. The integrated LDO and reference buffer reduce component count, aiding compact handheld and benchtop medical designs with strict reliability needs.
推薦
Automated Test Equipment (ATE)
ATE and bench instrumentation require converter accuracy that does not limit system error budgets; the ADS8900B's ±1 ppm INL ensures the digitizer contributes negligible linearity error at 20 bits. The 1-MSPS throughput accelerates multi-point DC parametric sweeps, and daisy-chain SPI simplifies multichannel synchronisation across board-level acquisition modules. Integrated reference buffering eases layout in dense test fixtures.
推薦
Data Acquisition (DAQ) Systems
General-purpose precision DAQ modules use the ADS8900B as a core digitizer: its fully differential inputs reject common-mode noise from long cable runs, and 104.5 dB SNR preserves 20 effective bits of dynamic range. The SPI-compatible interface with daisy-chain mode lets several ADCs share one controller port, and the 3.3V/1.8V supply levels integrate cleanly with modern low-voltage logic and isolated interfaces.
推薦
Vibration and Acoustic Analysis
Condition-monitoring systems digitize accelerometer and MEMS microphone outputs, where the ADS8900B's wide dynamic range (104.5 dB SNR) resolves early bearing-fault harmonics buried in noise. The 1-MSPS sampling covers ultrasonic frequency bands up to hundreds of kHz for spectral analysis. Pseudo-differential input supports single-ended IEPE-style front ends, and low 15 mW consumption benefits distributed sensor nodes.
推薦
推薦產品摘要
工程參考資料，適用於 ADS8900B — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | ADS8902B | ADS8904B | ADS8910B | AD7980 |
|---|---|---|---|---|---|
| Package | VQFN-20 (RGE) | VQFN-20 (RGE) - same | VQFN-20 (RGE) - same | VQFN-20 (RGE) - same | VQFN-20 (RGE) - verify pinout |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices |
| Resolution | 20 bit | 20 bit | 20 bit | 18 bit | 18 bit |
| Integrated Reference Buffer | Yes | Yes | Yes | Yes (family feature) | No (external buffer needed) |
| Integrated LDO | Yes | Yes | Yes | Yes (family feature) | No |
主要差異化特點
- Full 20-bit resolution at 1 MSPS (對比ADS8910B)
- Integrated reference buffer and LDO (對比AD7980)
- ±1 ppm INL linearity (對比ADS8920B)
設計說明
Decouple the 3.3V analog supply and 1.8V digital supply independently with 100 nF ceramic capacitors placed within 2 mm of the respective VQFN-20 (RGE) supply pins, plus bulk 10 uF capacitance per rail. Keep the analog input pair (INP/INN) routed as a matched differential pair away from SCLK/SDO digital traces to prevent coupling into the 104.5 dB SNR signal path. Use a solid ground plane under the ADC and stitch to the exposed pad.
The integrated reference buffer removes the need for a fast external buffer, but reference decoupling capacitors on REFT/REFM must follow datasheet recommendations exactly - undersized reference capacitance degrades AC performance at 1 MSPS. For maximum accuracy systems, compare the integrated LDO reference path against a low-noise external reference such as the REF5030A. Do not omit the LDO output capacitor on the CAP pin.
Drive CONVST from a clean, jitter-free source: aperture jitter directly limits SNR at 20-bit resolution. Daisy-chain SPI operation across multiple ADS890xB devices is supported, but verify SCLK rise/fall times and add series termination on long SPI runs to limit reflections and digital ground bounce that can corrupt the analog return path.
合規資訊
RoHS compliant per TI product page. REACH and halogen-free status not confirmed in provided data.
