Part A
ADS7809U
Texas Instruments
- Lifecycle
- Active
- Stock
- 6471 Stückzahl
- Package
- SOIC-20
- Series
- Datenerfassung mit Analog to Digital Converters (ADC)
Replacement verdict
Not a drop-in replacement
The ADS7822U and ADS7809U are not drop-in replacements for one another. The ADS7822U is a 12-bit, 200 kSPS micropower SAR ADC in an SOIC-8 package with a serial SPI interface, while the ADS7809U is a 16-bit, 100 kSPS SAR ADC in an SOIC-28 package with a parallel interface. They differ in resolution, sampling rate, package footprint, pin count, and digital interface, so a direct board-level substitution is not possible without redesign.
Different resolution
Different package footprint
Different digital interface
Different sampling rate
Parts at a glance
Part B
ADS7822U
Texas Instruments
- Lifecycle
- Active
- Stock
- 7079 Stückzahl
- Package
- SOIC-8
- Series
- Datenerfassung mit Analog to Digital Converters (ADC)
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADS7822U | ADS7809U | Why it matters |
|---|---|---|---|
| Resolution | 12 bit | 16 bit | Higher resolution provides finer quantization steps, which directly affects measurement accuracy and dynamic range. |
| Sampling Rate | 75 kSPS | 100 kSPS | Maximum throughput determines how fast the ADC can digitize signals in the application. |
| Number of Input Channels | 1 (single-ended) | 1 (single-ended) | Channel count defines how many analog signals can be measured without external multiplexing. |
| Input Type | Single-ended | Single-ended | Input configuration affects how the sensor or signal source must be connected and whether differential rejection is available. |
| Supply Voltage | 2.7 V to 5.25 V | 5 V (4.75 V to 5.25 V) | Supply range determines compatibility with the system power rail and low-voltage operation capability. |
| Interface | SPI (serial) | Parallel | Interface type must match the host controller; serial vs parallel changes pin count, board layout, and firmware. |
| Package | SOIC-8 | SOIC-28 | Package footprint and pin count affect PCB layout and whether a drop-in replacement is possible. |
| Reference | External | Internal | Internal vs external reference changes accuracy, drift behavior, and the need for additional external components. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Temperature range confirms suitability for industrial and extended-environment applications. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7809U | ADS7822U |
|---|---|---|
| Part Status | Active | Active |
| Number of Bits | 16 | 12 |
| Sampling Rate(Per Second) | 100k | 200k |
| Number of Inputs | 1 | 1 |
| Input Type | Single Ended | Pseudo-Differential |
| Data Interface | SPI, DSP | SPI |
| Configuration | S/H-ADC | S/H-ADC |
| Ratio - S / H: ADC | 1:1 | 1:1 |
| Number of A/D Converters | 1 | 1 |
| Architecture | SAR | SAR |
| Reference Type | External, Internal | External |
| Voltage - Supply, Analog | 5V | 2.7V ~ 3.6V, 5V |
| Voltage - Supply, Digital | 5V | 2.7V ~ 3.6V, 5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Series | - | microPOWER™ |
Frequently asked questions
What are the key architectural differences between the ADS7822U and ADS7809U?
The ADS7822U is a 12-bit, 200-kSPS micropower sampling analog-to-digital converter with a pseudo-differential input and a serial (SPI-compatible) interface, typically housed in an SOIC-8 package. The ADS7809U is a 16-bit, 100-kSPS sampling ADC with a successive-approximation register architecture, a full 16-bit parallel interface, and an internal reference, typically housed in an SOIC-28 package. The two devices differ fundamentally in resolution, throughput, interface type, and package footprint.
Can the ADS7822U be used as a direct drop-in replacement for the ADS7809U?
No. The ADS7822U and ADS7809U are not pin-compatible or functionally interchangeable. They differ in resolution (12-bit vs 16-bit), interface (serial vs parallel), package (SOIC-8 vs SOIC-28), and supply/support circuitry. A direct substitution is not possible without a complete redesign of the interface, layout, and signal chain.
How do the sampling rates and resolution of the two converters compare?
The ADS7822U offers 12-bit resolution at a maximum sampling rate of 200 kSPS, while the ADS7809U offers 16-bit resolution at a maximum sampling rate of 100 kSPS. The ADS7822U therefore provides higher throughput at lower resolution, whereas the ADS7809U provides higher resolution at a lower maximum throughput.
What interface types do the ADS7822U and ADS7809U use?
The ADS7822U uses a serial interface compatible with SPI and QSPI protocols, which minimizes pin count and is suited to space-constrained or isolated designs. The ADS7809U uses a full 16-bit parallel interface, which requires more I/O pins but allows high-speed data reads by a host processor or DSP.
How do the power consumption and supply requirements differ between the ADS7822U and ADS7809U?
The ADS7822U is a micropower device designed for low-power operation, typically drawing on the order of hundreds of microwatts at reduced throughput and operating from a single 2.7 V to 5.25 V supply. The ADS7809U is a higher-resolution converter that typically operates from a 5 V supply and consumes significantly more power to support its 16-bit SAR architecture and internal reference. Designers should consult the respective datasheets for exact supply current and power figures.
Which device is better suited for portable or battery-powered applications?
The ADS7822U is generally better suited for portable and battery-powered applications because of its micropower operation, small SOIC-8 package, and serial interface that reduces board space and I/O requirements. The ADS7809U, with its 16-bit parallel interface and higher power consumption, is more appropriate for higher-resolution instrumentation and data-acquisition systems where power and board space are less constrained.
Do the ADS7822U and ADS7809U have different input configurations?
Yes. The ADS7822U provides a pseudo-differential input configuration, allowing it to measure a signal relative to a reference point while rejecting common-mode noise. The ADS7809U is a 16-bit SAR converter with a specified analog input range and an internal reference, designed for high-accuracy absolute measurements. The input drive and reference requirements differ, so the analog front-end must be designed accordingly for each device.
What package and pin-count differences should a designer consider when choosing between the ADS7822U and ADS7809U?
The ADS7822U is supplied in an SOIC-8 package, while the ADS7809U is supplied in an SOIC-28 package. The difference in pin count and footprint means the two devices cannot share a common PCB land pattern, and the ADS7809U requires additional pins for the parallel data bus, control signals, and reference. PCB layout and routing must be designed specifically for the selected device.