ADS7817U - 12-Bit 200kHz Differential ADC | Texas Instruments
MPN： ADS7817U ✓ 啟用中ADS7817U 概覽
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.
直接替換替代品，適用於 ADS7817U — 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： ADS7817U （相同外形與佔位） — 差異在於 Converter Type, Package, Resolution, Sampling Rate.
ADS7809U
✅ 直接替換聯絡詢價
查看資料表 →ADS7817/2K5
✅ 直接替換📋 參考替代品（不在目錄中）
ADS7817U 最大額定值與電氣特性
| Converter Type | SAR ADC |
| 解析度 | 12 bit |
| 取樣率 | 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 |
| 介面 | Serial interface |
| 封裝 | 8-SOIC |
| 安裝類型 | Surface mount |
| 工作溫度範圍 | -40 C to +85 C |
| RoHS 狀態 | Compliant |
| Lead-Free Status | Lead-free |
ADS7817U 8-soic 腳位配置指南
ADS7817U（8-soic 封裝）的腳位配置。 此類比元件具有輸入、輸出與電源腳位。偏移歸零、補償與致能腳位配置請參閱製造商資料表。適用於訊號調理與放大器電路。
無詳細腳位定義資料： ADS7817U.
請參閱 資料表 以查看完整腳位配置。
典型應用
ADS7817U 適用於 6 應用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.
推薦
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.
推薦
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.
推薦
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.
推薦
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.
推薦
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.
推薦
推薦產品摘要
工程參考資料，適用於 ADS7817U — 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 | 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 |
主要差異化特點
- Lower nominal input-referred resolution with a reduced reference (對比ADS7817/2K5)
- Fully differential high-impedance input (對比ADS7809U)
- Low standby consumption with automatic power-down (對比ADS7817/2K5)
設計說明
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.
合規資訊
RoHS-compliant and lead-free status are identified for the ADS7817U. Other environmental, automotive, halogen-free, and conflict-minerals status requires manufacturer confirmation.
