ADS7817U - 12-Bit 200kHz Differential ADC | Texas Instruments
部品番号: ADS7817U ✓ 生産中ADS7817U 概要
An ADC is an analog-to-digital converter, a data-acquisition IC that samples an analog voltage and converts it into a numeric code for processing or transmission. The ADS7817U belongs to the SAR ADC family, where successive-approximation conversion provides accurate measurement at relatively low power consumption. Its differential input structure supports measurement of the voltage difference between two analog nodes rather than measuring a single node relative to ground.
Key features of the ADS7817U include 12-bit resolution, a 200 kHz sampling rate, a fully differential input, and automatic power-down. The reference range of 100 mV to 2.5 V allows the converter to be matched to low-amplitude sensor signals. The manufacturer describes the device as micropower and identifies differential input, low power, automatic power-down, and small size as central advantages for direct sensor-interface applications.
The conversion performance is also supported by a serial interface suitable for embedded measurement systems. The serial output can be connected to a microcontroller or other digital controller for conversion and data processing. The differential input architecture is particularly useful when the source has a small signal amplitude and common-mode voltage varies, because the useful measurement is the difference between the two input nodes.
Typical applications include industrial process measurement, battery and power-system monitoring, sensor signal acquisition, portable instrumentation, and low-power embedded control. The ADS7817U is appropriate when the design requires a compact, low-power SAR converter with a differential input and a selectable reference range.
When laying out the circuit, use short, symmetrical analog traces and place the input and reference components close to the converter. Confirm the supply, reference, analog input, digital interface, and ground connections against the manufacturer datasheet before fabrication. Treat the differential input and reference network as precision signal paths rather than general-purpose routing.
ドロップイン代替品: ADS7817U — 同一パッケージでピン互換。PCBの作り直しが必要な異なるパッケージの部品は除外されています。
このシリーズのバリエーション
同一シリーズでドロップイン互換のモデル: ADS7817U （同一形状・フットプリント） — 相違点: Converter Type, Package, Resolution, Sampling Rate.
ADS7809U
✅ ドロップイン価格はお問い合わせください
データシートを見る →ADS7817/2K5
✅ ドロップイン📋 参考代替品（カタログ未掲載）
ADS7817U 最大定格＆電気的特性
| Converter Type | SAR ADC |
| 分解能 | 12 bit |
| サンプリングレート | 200 kHz |
| Input Architecture | Fully differential analog input |
| Input Impedance | High impedance |
| Reference Voltage Range | 100 mV to 2.5 V |
| Input-Referred Resolution | 49 uV to 1.22 mV |
| Power-Down Current | 3 uA maximum |
| Power Consumption | Micropower at 200 kHz |
| Input Range | Bipolar differential input |
| インターフェース | Serial interface |
| パッケージ | 8-SOIC |
| 実装タイプ | Surface mount |
| 動作温度範囲 | -40 C to +85 C |
| RoHS ステータス | Compliant |
| Lead-Free Status | Lead-free |
ADS7817U 8-soic ピン配置ガイド
ADS7817U (8-soic パッケージ) のピン配置。 このアナログコンポーネントは、入力、出力、および電源ピンを備えています。オフセットナル、補償、イネーブルピンの設定については、メーカーのデータシートを参照してください。信号調整やアンプ回路に最適です。
詳細なピン配置データはありません: ADS7817U.
詳細は データシート をご参照ください。
主な用途
ADS7817U の用途: 6 件s: Industrial Sensor Signal Acquisition, Battery and Power-System Monitoring, Portable Instrumented Measurement, Precision Process-Control Front End, Embedded Data Acquisition Module, Analog Feedback and Monitoring System.
Industrial Sensor Signal Acquisition
The ADS7817U suits low-level differential measurements from sensors in industrial monitoring equipment. Its 12-bit resolution and 200 kHz sampling rate provide a practical balance between measurement speed and power consumption, while the high-impedance fully differential input helps acquire the voltage difference between a sensor output and its reference node. Setting the reference to 100 mV yields 49 uV input-referred resolution according to the manufacturer product page, improving sensitivity to small changes within the analog signal. Place the sensor and converter on the same side of the divider network, route the differential pair symmetrically, and keep the reference path short to preserve the benefit of the low-reference operating range.
おすすめ
Battery and Power-System Monitoring
The ADS7817U can monitor differential voltage changes in battery-management and power-system feedback circuits. The 200 kHz sampling rate allows repeated measurements of system dynamics, while automatic power-down and a 3 uA maximum shutdown current are useful when the converter operates intermittently. The differential input can reduce sensitivity to common-mode voltage if the signal source and converter share a suitable reference arrangement. For protection and control loops, the reference must remain within 100 mV to 2.5 V and the sampled signal must remain inside the device input limits. Use the manufacturer pin and electrical tables to establish startup sequencing, grounding, and digital-interface timing.
おすすめ
Portable Instrumented Measurement
The ADS7817U is appropriate for compact handheld or portable test equipment where each milliampere of operating power affects battery life. Its micropower operation at 200 kHz, automatic shutdown capability, and 8-SOIC package help reduce board area and energy use. A 12-bit converter also provides enough nominal resolution for monitoring many slow or moderate-bandwidth analog quantities without using a larger multiplexed converter. For portable designs, enable the converter only during measurement bursts, select capacitors suitable for the reference network, and verify settling behavior between acquisition cycles. The serial interface reduces parallel wiring and supports compact connections to a low-power microcontroller.
おすすめ
Precision Process-Control Front End
The ADS7817U can serve as the conversion stage in a process-control front end when the sensed variable is represented by a low-level differential voltage. The fully differential input supports cancellation of common-mode voltage, and the adjustable 100 mV to 2.5 V reference range lets designers match conversion resolution to the signal span. At the fastest stated 200 kHz sampling rate, the device is appropriate for supervisory control signals, though loop bandwidth and acquisition latency must be included in the control design. Use low-noise reference components and a symmetric PCB layout, and confirm input settling through the recommended application circuit rather than assuming the source impedance is unrestricted.
おすすめ
Embedded Data Acquisition Module
The ADS7817U fits embedded acquisition modules that convert one analog differential channel and transfer the result through a serial interface. Its 200 kHz sampling rate supports responsive measurements, while 12-bit resolution limits code granularity according to the selected reference. The 8-SOIC package keeps the converter compact without requiring a large package with unused pins. In an embedded controller design, use the serial clock and data lines for isolated or short board-level communication, and confirm logic levels against the controlling device. Automatic power-down is particularly useful in cyclic acquisition systems, where the controller can disable the converter between bursts to reduce standby current.
おすすめ
Analog Feedback and Monitoring System
The ADS7817U can digitize a differential feedback signal for supervision, diagnostics, or adaptive control in mixed-signal systems. Its high-impedance input avoids loading the measured node more than necessary, and the selectable reference supports either fine resolution on small signals or a wider range on larger signals. The 12-bit result is especially practical for supervisory loops where the controller must observe operating conditions without replacing the main high-resolution measurement channel. Keep the converter reference and analog input away from fast digital return currents, provide a quiet ground path, and follow the manufacturer grounding arrangement. Digital reads of the serial interface should be synchronized to the specified conversion and clock timing.
おすすめ
おすすめ製品の概要
エンジニアリング参考データ: ADS7817U — 比較、設計ガイダンス、コンプライアンス情報。
選定ガイド
代替品との比較
| パラメータ | この製品 | ADS7809U | ADS7817/2K5 |
|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 8-SOIC | 8-SOIC | 8-SOIC |
| Resolution | 12 bit | 12 bit | 12 bit |
| Input Architecture | Fully differential | Differential | Fully differential |
| Reference Voltage | 100 mV to 2.5 V | 2.5 V reference option | 2.5 V |
| Interface | Serial | Serial | Serial |
主な差別化要因
- Lower nominal input-referred resolution with a reduced reference （vs ADS7817/2K5)
- Fully differential high-impedance input （vs ADS7809U)
- Low standby consumption with automatic power-down （vs ADS7817/2K5)
設計ノート
Route the differential analog input as a compact, symmetrical pair and keep it away from digital clock and serial-data traces. Place input and reference components close to their associated pins, and use a continuous ground plane without splitting return paths beneath the converter. The small reference range can improve nominal resolution to 49 uV, but reference noise, source impedance, and layout leakage can still affect the usable measurement noise.
Use the manufacturer recommended bypass capacitance and power-supply arrangement for the ADS7817U. Automatic power-down can reduce standby demand to no more than 3 uA, so control enable sequencing carefully when the converter shares a supply with sensitive analog circuitry. Confirm that reference settling and supply startup occur in the required order to avoid invalid early conversion results.
Do not treat the 12-bit nominal resolution as complete system accuracy. Include reference tolerance, analog front-end noise, source impedance, settling time, and differential-input common-mode limits in the error budget. Also verify the exact ordering suffix: ADS7817U and ADS7817/2K5 have different reference configurations, and a family-level comparison does not by itself prove that a device is a drop-in replacement.
コンプライアンス情報
RoHS-compliant and lead-free status are identified for the ADS7817U. Other environmental, automotive, halogen-free, and conflict-minerals status requires manufacturer confirmation.
