ADS821U - 10-Bit 40-MSPS ADC | Texas Instruments | Signal Capture
MPN: ADS821U ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
ADS821U Overview
An ADC is a data-acquisition IC that samples an analog voltage and converts it into a digital code for processing by a microcontroller, DSP, FPGA, or test system. The ADS821U belongs to the pipeline ADC family, with its resolution, conversion rate, input architecture, reference, and acquisition circuitry defining its role within a broader analog-to-digital conversion and signal-processing hierarchy.
The converter's principal features are 40 MSPS operation, 10-bit resolution, 58 dB SNR, and 9.3-bit ENOB. The no-missing-codes feature supports deterministic output behavior, while the internal track-and-hold circuit simplifies front-end design. The verified product information also identifies a 380 mW low-power figure and supports SOIC-28 and SSOP-28 family packaging, with ADS821U specifically supplied in the 28-pin SOIC package.
Technically, the ADS821U is designed for single-ended or differential input acquisition. An internal reference and internal track-and-hold function reduce the number of external support blocks required in a conventional measurement chain. However, signal bandwidth, input range, timing, reference behavior, and electrical limits must be confirmed from the manufacturer datasheet before finalizing analog front-end and clock design.
Typical uses include communications and signal-analysis equipment, industrial measurement systems, test and measurement instruments, and embedded control or processing platforms that need a 40-MSPS conversion rate. The 10-bit code width is appropriate where the required information bandwidth is greater than the precision demanded from every individual sample.
A key design consideration is that the ADC does not replace the surrounding analog system. Input scaling, source impedance, anti-alias filtering, clock jitter, grounding, decoupling, and digital-interface timing determine practical performance. Confirm the pinout and pin functions in the official datasheet before layout or replacement work.
This page combines verified manufacturer and distributor information with application guidance, practical design notes, and explicitly qualified replacement considerations. Unverified prices, complete pin functions, and unconfirmed cross-brand drop-in equivalents are not inferred.
Drop-in alternatives for ADS821U — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ADS821U-1
✅ Drop-In📋 Reference alternative (not in catalog)
ADS821U Maximum Ratings & Electrical Characteristics
| Converter Type | Pipelined analog-to-digital converter |
| Resolution | 10 bit |
| Sampling Rate | 40 MSPS |
| Input Configuration | 1 input; single-ended or differential |
| Signal-to-Noise Ratio | 58 dB |
| Effective Number of Bits | 9.3 bit |
| Power Consumption | 380 mW |
| Internal Reference | Internal |
| Track-and-Hold | Internal |
| Missing Code Behavior | No missing codes |
| Input Voltage | 1.25 V |
| Package | SOIC-28 (DW) |
| Pin Count | 28 pin |
| Mounting Type | Surface mount |
| Operating Temperature | -40 C to +85 C |
| Screening Level | Industrial |
| Architecture | Monolithic |
ADS821U soic-28 (dw) Pin Configuration Guide
Pin configuration for ADS821U (soic-28 (dw) package). This analog component features input, output, and power supply pins. Refer to the manufacturer datasheet for offset null, compensation, and enable pin configurations. Ideal for signal conditioning and amplifier circuits.
No detailed pinout data available for ADS821U.
Refer to the datasheet for full pin configuration.
Typical Applications
ADS821U is suitable for 6 applications: Communications Signal Capture, Test and Measurement Instrumentation, Industrial Measurement Systems, Waveform Data Acquisition, Embedded Control and Monitoring, Sensor Signal Digitization.
Communications Signal Capture
The ADS821U fits communications signal capture when the system needs 40-MSPS sampling and a 10-bit digital result. Its single-ended or differential input support lets the analog front end match the source, while the internal track-and-hold helps synchronize acquisition. The 58 dB SNR figure is the verified family-level metric; engineers should still verify bandwidth, input range, clocking, and output timing from the datasheet before setting the communications bandwidth.
Recommended
Test and Measurement Instrumentation
ADS821U is appropriate for measurement front ends that sample waveforms at up to 40 MSPS and require a 10-bit code width. The internal reference and internal track-and-hold reduce support-circuit complexity, while the 28-pin SOIC package supports conventional surface-mount assembly. Use the converter when 9.3-bit ENOB and 58 dB SNR align with the instrument's dynamic-range requirement; for higher precision, select an ADC with a verified higher resolution instead.
Recommended
Industrial Measurement Systems
The ADS821U can serve as the acquisition element in an industrial measurement system that needs real-time sampling of rapidly changing analog conditions. Its 40-MSPS throughput supports dense time-domain data, and the 10-bit resolution provides 1,024 digital code levels for digital transfer. The industrial screening level and -40 C to +85 C temperature specification are verified, but the system designer must still account for sensor excitation, isolation, grounding, and safety requirements.
Recommended
Waveform Data Acquisition
ADS821U is well suited to waveform acquisition when the required record rate is no greater than 40 MSPS and 10-bit resolution is sufficient. The internal track-and-hold and reference support a compact acquisition chain, while the SOIC-28 package is practical for conventional PCB assembly. Designers should pair the ADC with anti-alias filtering, a low-jitter clock, adequate analog drive, and a digital processor that supports the converter's verified output interface.
Recommended
Embedded Control and Monitoring
ADS821U can be used in embedded monitoring systems that need faster sampling than a general-purpose low-speed ADC. The 10-bit result can be transferred to a microcontroller or FPGA, while the single-ended or differential input selection supports different sensor-interface architectures. The design should validate acquisition timing, output coding, and supply sequencing against the datasheet, especially when the monitored signal bandwidth approaches the converter's sampling capability.
Recommended
Sensor Signal Digitization
ADS821U is applicable when a sensor signal must be digitized rapidly enough to capture transients or waveform detail. Its 40-MSPS sampling rate and 10-bit resolution can be matched to medium-bandwidth sensor outputs, while the internal track-and-hold helps isolate the sampling instant. For sensor nodes, engineers must design input protection, biasing, filtering, and grounding around the actual sensor impedance; the verified 1.25 V input figure should not be treated as a complete front-end specification without datasheet context.
Recommended
Recommended Products Summary
Engineering reference data for ADS821U — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ADS821U-1 |
|---|---|---|
| Package | SOIC-28 (DW) | SOIC-28 (DW) |
| Brand | Texas Instruments | Texas Instruments |
Key Differentiators
- 40-MSPS conversion rate (vs ADS821U-1)
- 10-bit resolution with 9.3-bit ENOB (vs ADS821U-1)
- Integrated reference and track-and-hold (vs ADS821U-1)
Design Notes
Keep the analog input path short and controlled. Place the ADC input pins and their associated input network according to the manufacturer layout guidance, use a low-impedance source where required, and minimize trace length between the driver, anti-alias filter, and ADC. A 40-MSPS converter can respond to high-frequency noise and timing errors even though its nominal output is only 10 bits.
Build the supply and decoupling network around the verified 380 mW device figure, while checking the datasheet for the exact operating supply and current conditions. Place required bypass capacitors close to the relevant supply pins, provide a low-impedance return path, and keep switching-converter noise away from sensitive analog traces. Estimated board power should include the ADC, reference, driver, interface, and support circuitry rather than the ADC value alone.
Do not treat a functional-equivalent ADC as a drop-in replacement without checking all 28 pins and the package drawing. Verify input range, reference behavior, clock polarity and timing, output coding, power sequencing, and thermal limits against the official datasheet. The supplied data identifies ADS821U as SOIC-28, but it does not provide the complete pin functions needed to certify an alternate part.
Compliance Information
The supplied verified data identifies industrial screening but does not state RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status. These fields remain unknown rather than inferred.
