ADS7808U - 12-Bit 100 kHz SAR ADC | Texas Instruments
MPN： ADS7808U ✓ 啟用中ADS7808U 概覽
An ADC is an analog-to-digital converter, a mixed-signal semiconductor that converts a continuous voltage into a numeric code for measurement, control, or processing. The ADS7808 belongs to the SAR ADC hierarchy, where successive approximation compares the sampled input against a capacitor DAC. Compared with flash, pipelined, and sigma-delta converters, this architecture provides straightforward low-power conversion and a compact serial interface suitable for embedded acquisition systems.
Key features include a maximum sampling rate of 100 kHz, 12-bit resolution, and linearity specified as ±1/2 LSB for INL and DNL. The converter operates from a single +5 V supply, uses a serial output, and accepts one analog input. Its maximum power dissipation is 100 mW. Pin compatibility with the 16-bit ADS7809 provides an upgrade path when greater resolution is needed without changing the package architecture.
Internally, the ADS7808 uses state-of-the-art CMOS structures and supports conversion with its internal clock or synchronization to an external data clock. An output synchronization pulse simplifies interfacing with DSP-based systems. The internal reference can be used for standalone operation, while an external reference offers a route to improve stability or share precision reference circuitry across multiple channels.
Typical applications include industrial process measurement, factory automation, DSP data acquisition, closed-loop control, and embedded instrumentation. The 100 kHz conversion rate and 12-bit code width are suitable for signals where rapid sampling and moderate resolution are required. The device is also appropriate for battery-powered or compact industrial systems because its stated maximum power dissipation is only 100 mW.
When designing a circuit around the ADS7808U, verify the selected input range, reference configuration, logic levels, and digital interface timing against the manufacturer datasheet. Decoupling and analog signal-path layout are critical because the converter contains a sample-and-hold stage and may be sensitive to supply and reference noise. Confirm the complete conversion and data-read cycle before synchronizing it to a DSP.
This page consolidates verified manufacturer and distributor information, package details, application guidance, and clearly qualified drop-in alternatives. It also highlights where direct cross-reference evidence is limited and where engineers must verify pin behavior, electrical limits, and availability before approving a replacement.
直接替換替代品，適用於 ADS7808U — 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： ADS7808U （相同外形與佔位） — 差異在於 Package, Resolution, Number of Input Channels, Sampling Rate, Supply Voltage.
ADS7808U/1K
✅ 直接替換📋 參考替代品（不在目錄中）
ADS7808UG4
✅ 直接替換📋 參考替代品（不在目錄中）
ADS7808UE4
✅ 直接替換📋 參考替代品（不在目錄中）
ADS7822U
✅ 直接替換聯絡詢價
查看資料表 →ADS7807UBE4
✅ 直接替換聯絡詢價
查看資料表 →ADS7808U 最大額定值與電氣特性
| 解析度 | 12 bits |
| Conversion Time | 10 µs |
| 取樣率 | 100 kHz |
| Signal-to-Noise and Distortion | 72 dB SINAD with 45 kHz input |
| Integral Nonlinearity | ±1/2 LSB |
| Differential Nonlinearity | ±1/2 LSB |
| Number of Input Channels | 1 channel |
| Input Ranges | 6 specified ranges |
| ADC Architecture | 12-bit capacitor-based SAR |
| Sample-and-Hold | Internal sample-and-hold circuit |
| Reference | Internal or external reference |
| 供應電壓 | +5 V |
| Maximum Power Dissipation | 100 mW |
| Output Interface | Serial output |
| Clocking | Internal clock or external data-clock synchronization |
| Output Synchronization | Synchronization pulse |
| 封裝 | 20-pin SOIC, 0.3 inch body width |
| 安裝類型 | Surface mount |
| 工作溫度 | -40 °C to +85 °C |
| Pin-Compatible Upgrade | 16-bit ADS7809 |
| Recommended Voltage References | REF02 and REF102 |
ADS7808U 20-pin soic, 0.3 inch body width 腳位配置指南
ADS7808U（20-pin soic, 0.3 inch body width 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： ADS7808U.
請參閱 資料表 以查看完整腳位配置。
典型應用
ADS7808U 適用於 6 應用s: Industrial Process Measurement, Factory Automation and Control, DSP Data Acquisition, Embedded Instrumentation, Closed-Loop Feedback Control, Portable Measurement Equipment.
Industrial Process Measurement
The Texas Instruments ADS7808U fits industrial process measurement because it combines a 100 kHz sampling rate, 12-bit resolution, and 72 dB SINAD with a 45 kHz input. Its six specified input ranges allow a conditioned sensor signal to be mapped to an appropriate converter range. The converter is placed behind the transmitter’s signal-conditioning network, with the serial result read by a controller or DSP. The 10-µs conversion time supports rapid acquisition, while the single +5 V supply simplifies system integration. Designers should still verify input bandwidth, settling time, isolation, and industrial surge requirements, because the converter does not replace the protection and conditioning circuitry ahead of its analog input.
推薦
Factory Automation and Control
ADS7808U is appropriate for factory automation loops that measure a single analog process variable and need deterministic digital conversion. Its 100 kHz sampling capability and 10-µs conversion time allow the controller to observe changing actuator or sensor conditions more rapidly than a slow display-oriented ADC. A typical circuit conditions the sensor current or voltage, connects it to one of the six supported input ranges, and transfers the 12-bit code through the serial interface. The single +5 V operation reduces supply complexity. For machinery, isolate the analog front end and validate EMC, grounding, and transient protection independently rather than assuming the bare ADC package provides industrial ruggedness.
推薦
DSP Data Acquisition
The ADS7808U can feed a DSP-based acquisition system that needs compact, low-power conversion without the complexity of a high-resolution multichannel converter. Its internal clock supports standalone operation, while external data-clock synchronization and the output synchronization pulse help align acquisition with digital processing. The serial interface reduces the number of signal lines required around a 20-pin SOIC, and the specified 100 mW maximum power dissipation supports space- and power-conscious embedded designs. System designers should calculate the complete sample transaction, including acquisition, conversion, and serial transfer, and ensure the DSP supports the converter’s timing and logic levels.
推薦
Embedded Instrumentation
ADS7808U is well suited to embedded instrumentation where a compact instrument must acquire an analog measurement and present it digitally. The 12-bit code provides 4096 discrete levels, while the 100 kHz sampling rate and 72 dB SINAD are useful for dynamic measurement rather than only static readings. The converter can use its internal reference for simplicity or an external reference when greater system-level stability is required. REF02 and REF102 are specifically identified as recommended references. Place the input filter, reference, and bypass components close to the device, and account for the ADC’s front-end settling behavior when changing the selected input range.
推薦
Closed-Loop Feedback Control
The ADS7808U can serve as the measurement element in a closed-loop feedback controller because it converts a conditioned analog feedback signal in 10 µs and supports external-clock synchronization. The 12-bit resolution gives the controller 4096 code levels, and the six available input ranges can match different actuator feedback signals. The resulting code is read serially and used to adjust power, position, flow, or another control variable. Designers should confirm that the loop bandwidth, acquisition latency, serial transfer time, and output-code step size meet the control dynamics. The ADC should be paired with filtering that rejects noise without adding excessive group delay.
推薦
Portable Measurement Equipment
The ADS7808U is appropriate for portable measurement equipment because it offers a 100 kHz sampling rate and a 12-bit result in a compact 20-pin SOIC, with maximum power dissipation specified at 100 mW. It can operate from one +5 V supply and use an internal reference to reduce the number of external precision components. In a handheld tester, the analog sensor or input network feeds the ADC, while a controller reads the serial data and applies calibration. Battery operation still requires careful attention to regulator efficiency, analog noise, and input-signal settling, but the converter’s stated power ceiling supports space-constrained designs when thermal margins are acceptable.
推薦
推薦產品摘要
工程參考資料，適用於 ADS7808U — 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 | ADS7808U/1K | ADS7808UG4 | ADS7808UE4 | ADS7822U | ADS7807U |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 20-pin SOIC | 20-pin SOIC - same | 20-pin SOIC - same | 20-pin SOIC - same | 20-pin SOIC - same | 20-pin SOIC - same |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Input Channels | 1 channel | 1 channel | 1 channel | 1 channel | 1 channel | 1 channel |
主要差異化特點
- Documented 72 dB SINAD performance (對比ADS7808U/1K)
- Pin-compatible path to 16-bit resolution (對比ADS7809)
- Low stated power dissipation (對比ADS7808UG4)
- Multiple analog ranges with external-reference flexibility (對比ADS7808UE4)
設計說明
Route the analog input and reference signals away from the serial clock and data lines. Keep the input conditioning components close to ADS7808U, use a short ground-return path, and place supply bypass capacitors at the device power pins. The converter contains a sample-and-hold stage and a 12-bit SAR core, so input settling and return-path geometry directly affect code accuracy even when the clock rate is below 100 kHz.
Design the +5 V rail to support the ADC and the required reference option without introducing noise into the conversion. The verified maximum power dissipation is 100 mW, but that figure does not determine total system heat or analog supply quality. Use separate routing or filtering between noisy digital circuitry and the ADC supply when necessary, and verify reference startup and settling before taking the first valid conversion.
Do not treat the 100 kHz sampling rate as permission to change input ranges without allowing acquisition and reference settling time. The 10-µs conversion time covers conversion, while the complete system transaction also includes command handling and serial transfer. Confirm the selected input range, clock polarity, conversion-start behavior, and output synchronization using the manufacturer datasheet to avoid reading stale or incorrectly scaled conversion data.
Use a controlled reference source when measurement repeatability depends on more than the internal reference can provide. Texas Instruments identifies REF02 and REF102 as recommended references, but each reference still requires suitable decoupling and grounding. Account for reference noise, temperature drift, and startup behavior in the system error budget. For externally clocked operation, ensure the data clock and synchronization pulse meet the interface timing shown in the manufacturer datasheet.
合規資訊
The supplied manufacturer and distributor results do not extract explicit RoHS, REACH, lead-free, halogen-free, or conflict-minerals statements. AEC-Q100 is not applicable to the general-purpose ADC category; no automotive-qualified ADS7808U variant is identified in the verified data.
