ADS7825U - 16-Bit 4-Channel SAR ADC | Texas Instruments
Артикул: ADS7825U ✓ АктивенADS7825U Обзор
An ADC is an analog-to-digital converter, a semiconductor that converts continuously varying voltage signals into numerical values for processing, measurement, or control. The ADS7825 belongs to the SAR ADC family, where a sample-and-hold circuit captures an input and an internal successive-approximation conversion process determines its digital code. Within the broader hierarchy, it is a data-acquisition IC and interface IC for industrial instrumentation, process control, and embedded measurement systems.
The four-input analog multiplexer allows one ADC to service four single-ended input channels. Its ±10 V range removes the need to build external attenuation when measuring bipolar industrial signals, while channel-to-channel matching of ±0.1% improves consistency between measurements. The 16-bit resolution provides 65,536 code levels. Operating from one +5 V supply simplifies system power planning, and the parallel or serial interface supports connection to both legacy parallel buses and modern serial processors.
The sampling architecture provides a conversion time of 25 us maximum and supports 40 kSPS operation in the verified product data. A power-down mode reduces consumption to 50 uW, making the converter practical for intermittently sampled equipment. Internal or external reference capability gives designers flexibility in selecting the reference strategy, while parallel and serial outputs provide migration options between microprocessor architectures. The 28-pin SOIC package supports conventional surface-mount assembly.
Typical uses include industrial process-control input modules, PLC analog input cards, laboratory data loggers, and factory instrumentation. The ADS7825U is also appropriate for bipolar sensor acquisition where signals exceed the supply rails, provided the analog inputs remain within the specified ±10 V range. For communications or instrumentation front ends, the serial interface can reduce wiring, while the parallel interface can simplify deterministic acquisition in older controller designs.
A critical design consideration is preserving the converter's measurement accuracy through careful analog routing. Keep the ±10 V inputs away from high-current switching nodes, provide stable reference and supply bypassing, and respect the input settling time required by the sample-and-hold stage. Verify the actual input range, absolute maximum ratings, and acquisition timing from the manufacturer datasheet before applying signals or changing the reference network.
This page consolidates verified manufacturer and distributor information, identifies same-footprint alternatives, compares the ADS7825U with candidate replacements, and adds practical selection and circuit-design guidance. It is intended to help engineers identify whether the 16-bit, four-channel, ±10 V ADC fits a design before downloading the complete ADS7825 datasheet and beginning schematic capture.
Аналоги без доработки для ADS7825U — тот же корпус, pin-to-pin совместимость. Компоненты в других корпусах, требующие переработки PCB, исключены.
Варианты в этой серии
Модели той же серии, совместимые без доработки с ADS7825U (тот же форм-фактор и посадочное место) — отличается по Number of Input Channels, Package, Sampling Rate, Supply Voltage, Channel-to-Channel Matching.
ADS7824UB/1KG4
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Открыть даташит →ADS7825UE4
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Открыть даташит →ADS7825U Максимальные параметры и электрические характеристики
| ADC Type | 16-bit successive-approximation ADC |
| Number of Input Channels | 4 single-ended inputs |
| Частота дискретизации | 40 kSPS |
| Conversion Time | 25 us maximum |
| Integral Nonlinearity | ±2.0 LSB maximum |
| Analog Input Range | ±10 V |
| Channel-to-Channel Matching | ±0.1% |
| Напряжение питания | +5 V |
| Maximum Power Dissipation | 50 mW |
| Power-Down Current | 50 uW |
| Data Output Interface | Parallel or serial |
| Reference | Internal or external |
| Диапазон рабочих температур | -40 C to +85 C |
| Корпус | 28-pin SOIC (DW) |
| Тип монтажа | Surface mount |
| Process Technology | CMOS |
Руководство по цоколевке ADS7825U в корпусе 28-pin soic (dw)
Цоколевка для ADS7825U (корпус 28-pin soic (dw)). Этот аналоговый компонент имеет выводы входа, выхода и питания. Обратитесь к техническому описанию производителя для конфигураций выводов балансировки нуля, коррекции и разрешения. Идеально подходит для схем обработки сигналов и усилителей.
Нет подробных данных о распиновке для ADS7825U.
Обратитесь к даташиту для полной конфигурации выводов.
Типичное применение
ADS7825U подходит для 6 применениеs: Industrial Process-Control Input Module, PLC Analog Input Card, Laboratory Data Logger, Factory Sensor Acquisition, Precision Instrumentation Front End, Multichannel Data-Acquisition System.
Industrial Process-Control Input Module
The ADS7825U fits four-channel industrial process inputs because it combines 16-bit resolution, a verified ±10 V range, and ±0.1% channel-to-channel matching in a 28-pin SOIC. Its four-input multiplexer allows one converter to monitor several pressure, temperature, or level transmitter signals without requiring four separate converter packages. The 25 us maximum conversion time and 40 kSPS throughput are sufficient for many supervisory control loops, while the ±10 V scaling network removes a separate front-end attenuator. In a PLC or distributed I/O module, the converter can sit behind protected input terminals and communicate through its parallel or serial interface. Designers should still budget for transient protection, settling time, reference stability, and isolation or grounding appropriate to the field wiring.
Рекомендуется
PLC Analog Input Card
ADS7825U is appropriate for a PLC analog input card that must acquire several bipolar process signals with 16-bit numerical resolution. The verified 4-channel, ±10 V architecture maps naturally to common 0–10 V and −10 V to +10 V industrial inputs, while 40 kSPS supports scanning channels without the complexity of a very high-speed converter. The serial output can connect to an embedded controller with fewer signal traces, while the parallel option supports legacy CPU interfaces. System-level accuracy still depends on the input protection network, reference design, analog ground arrangement, and calibration strategy. The converter’s −40 C to +85 C rating suits industrial card requirements, but isolation and surge protection must be evaluated separately from the ADC itself.
Рекомендуется
Laboratory Data Logger
The ADS7825U can serve as the analog front end of a laboratory data logger measuring four slow or medium-speed bipolar sensor channels. Its 16-bit resolution preserves low-level measurement detail, and the ±10 V range accepts outputs from many industrial transducers without a separate gain stage. A 40 kSPS conversion capability provides useful timing margin for periodic logging while keeping power dissipation at no more than 50 mW. The internal or external reference choice lets the designer balance board area against reference quality and calibration requirements. For accurate laboratory results, the input front end should include low-leakage protection, guarded routing, stable reference bypassing, and software oversampling or averaging only where the required source impedance and acquisition timing support those techniques.
Рекомендуется
Factory Sensor Acquisition
ADS7825U is well matched to factory sensor acquisition nodes that monitor up to four analog sensors through a shared converter. The device’s 16-bit output represents 65,536 code levels, and the specified ±0.1% channel matching helps maintain consistent readings across multiple sensor channels. Its ±10 V input capability is useful for compatible pressure, flow, and position transducers, while the single +5 V supply simplifies system architecture. In a compact embedded acquisition board, the 28-pin SOIC is easy to assemble and available in both parallel and serial interface configurations. The design must account for sensor settling time, common-mode transients, connector protection, and reference drift. Power-down operation at 50 uW is useful for duty-cycled nodes that spend most of their time between measurement bursts.
Рекомендуется
Precision Instrumentation Front End
ADS7825U can serve as the sampling ADC in precision instrumentation when the target signal bandwidth fits its 25 us maximum conversion time. The combination of ±2.0 LSB maximum integral nonlinearity, 16-bit nominal resolution, and laser-trimmed ±10 V scaling provides a useful foundation for accurate measurements. Internal or external reference support lets an instrument maker choose a simple internal source or a carefully controlled external reference for improved calibration flexibility. The serial interface reduces wiring in compact instruments, whereas parallel output can assist deterministic legacy acquisition systems. To preserve converter performance, analog and digital return currents should be separated carefully, reference and supply pins should be bypassed near the device, and every input should be allowed to settle before acquisition begins.
Рекомендуется
Multichannel Data-Acquisition System
ADS7825U is useful in multichannel acquisition systems where four analog inputs must be converted into 16-bit data for a processor or FPGA. The four-way multiplexer conserves board area, and the parallel or serial output allows the same converter family to support different control architectures. At 40 kSPS, the part suits continuous monitoring of process variables, vibration channels, and equipment status signals rather than high-frequency waveform capture. A microcontroller such as STM32F072CBT6TR can use the serial interface to initiate conversion and retrieve results, while an FPGA can exploit the parallel interface when deterministic timing is important. System designers must verify acquisition timing, define which channels are grounded or unused, and prevent fast digital or switching signals from coupling into the ±10 V analog inputs.
Рекомендуется
Сводка рекомендуемых товаров
Справочные инженерные данные для ADS7825U — сравнение, рекомендации по проектированию и информация о соответствии.
Руководство по выбору
Сравнение с аналогами
| Параметр | Этот товар | ADS7824U | ADS7825UE4 |
|---|---|---|---|
| Package | 28-pin SOIC (DW) | 28-pin SOIC | 28-pin SOIC (DW) |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments |
Ключевые отличия
- Provides 16-bit conversion resolution in a four-channel package (против ADS7824U)
- Directly supports industrial bipolar signal acquisition (против ADS7824U)
- Supports both modern serial and legacy parallel processor interfaces (против ADS7824U)
Заметки по проектированию
Do not treat physical pin compatibility as proof of electrical interchangeability. The manufacturer material identifies ADS7825 as pin-compatible with ADS7824, but the lower-resolution ADS7824 class can change the usable measurement resolution. Before replacing ADS7825U with ADS7824U, compare INL, offset error, gain error, conversion time, acquisition timing, reference behavior, and output coding in the two datasheets.
Route the four ±10 V inputs away from digital clock, serial-data, and switching-supply traces. Use a continuous analog ground plane where appropriate, keep the reference and supply bypass paths short, and place input and reference components near their associated pins. High-value input traces should be guarded where crosstalk could affect the converter, and the unused-channel state must follow the manufacturer’s recommended connection.
Estimated: at the verified 50 mW maximum dissipation, a 30 C/W junction-to-ambient resistance would produce approximately a 1.5 C rise above ambient; this estimate is not a datasheet thermal rating. Use the ADS7825U’s maximum dissipation only as a worst-case design bound. Actual board temperature depends on copper area, neighboring heat sources, airflow, and package geometry, so verify thermal margin using the manufacturer data for the final PCB.
Информация о соответствии
The supplied manufacturer and distributor extracts do not explicitly state the required compliance status. The -40 C to +85 C industrial temperature range does not by itself establish AEC-Q100 qualification.