Part A
ADS7822U
Texas Instruments
- Lifecycle
- Active
- Stock
- 7079 PCS
- Package
- SOIC-8
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Not a drop-in replacement
The ADS7822U and ADS7804UB are not drop-in replacements for one another. They differ in resolution, package footprint, and digital interface architecture, so substituting one for the other requires board-level redesign and firmware changes rather than a direct swap.
Different resolution
Different package footprint
Different digital interface
Different conversion architecture
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 | ADS7804UB | Why it matters |
|---|---|---|---|
| Resolution | 12 bit | 12 bit | Both are 12-bit ADCs, so resolution is equivalent and not a differentiator for substitutability. |
| Sampling Rate | 75 kSPS | 100 kSPS | The ADS7804UB offers a higher maximum throughput, which matters for faster signal acquisition requirements. |
| Input Type | Single-ended | Single-ended | Both accept single-ended inputs, so the input configuration is compatible for direct substitution. |
| Interface | SPI (serial) | Parallel | The interface differs significantly (serial SPI vs parallel), which affects microcontroller pin count and firmware design. |
| Supply Voltage | 2.7 V to 5.25 V | 5 V | The ADS7822U supports a wider low-voltage range, while the ADS7804UB requires a 5 V supply, affecting system power design. |
| Package | SOIC-8 | SOIC-28 | Different package footprints and pin counts mean the parts are not drop-in compatible on the same PCB layout. |
| Reference | External | Internal | The ADS7804UB includes an internal reference, simplifying design, while the ADS7822U requires an external reference. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Both share the same industrial temperature range, so environmental compatibility is equivalent. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7822U | ADS7804UB |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Part Status | Active | Active |
| Number of Bits | 12 | 12 |
| Sampling Rate(Per Second) | 200k | 100k |
| Number of Inputs | 1 | 1 |
| Input Type | Pseudo-Differential | Single Ended |
| Data Interface | SPI | Parallel |
| 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 | External, Internal |
| Voltage - Supply, Analog | 2.7V ~ 3.6V, 5V | 5V |
| Voltage - Supply, Digital | 2.7V ~ 3.6V, 5V | 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 ADS7804UB?
The ADS7822U is a 12-bit, 200-kSPS micropower sampling analog-to-digital converter with a pseudo-differential input and an SPI-compatible serial interface, housed in an SOIC-8 package. The ADS7804UB is a 12-bit, 100-kSPS complete sampling ADC with a parallel 8-bit/12-bit interface, an internal reference, and a successive-approximation register architecture, housed in a 28-pin SOIC package.
Do the ADS7822U and ADS7804UB have compatible digital interfaces?
No. The ADS7822U uses a serial SPI/QSPI/MICROWIRE-compatible interface, while the ADS7804UB provides a parallel microprocessor interface with selectable 8-bit or 12-bit bus width. They are not pin-to-pin or interface-compatible and require different host controller connections.
How do the sampling rates of the ADS7822U and ADS7804UB compare?
The ADS7822U supports a throughput rate of up to 200 kSPS, whereas the ADS7804UB is specified for a maximum throughput of 100 kSPS. The ADS7822U therefore offers twice the sampling rate of the ADS7804UB.
What are the input voltage ranges for the ADS7822U and ADS7804UB?
The ADS7822U operates with a single supply from 2.7 V to 5.25 V and provides a pseudo-differential input with a 0 V to VREF range, where VREF can be derived from the supply. The ADS7804UB operates from a single 5 V supply and offers a bipolar ±10 V input range with an internal 2.5 V reference and on-chip input scaling.
How do the power consumption figures of the ADS7822U and ADS7804UB differ?
The ADS7822U is a micropower device drawing approximately 1.6 mW at 200 kSPS with a 5 V supply, and it features a power-down mode that reduces consumption to microwatt levels between conversions. The ADS7804UB, as a complete parallel-interface ADC with internal reference, typically dissipates significantly more power, on the order of 100 mW during operation.
Are the ADS7822U and ADS7804UB available in the same package type?
No. The ADS7822U is offered in an 8-pin SOIC package, while the ADS7804UB is offered in a 28-pin SOIC package. The package footprints, pin counts, and pin functions differ, so they are not drop-in replacements for one another.
Can the ADS7822U directly replace the ADS7804UB in an existing design?
No. The two devices differ in package footprint, pin count, digital interface (serial versus parallel), input configuration (pseudo-differential unipolar versus bipolar ±10 V), supply requirements, and throughput. A direct substitution is not possible without a complete redesign of the interface, power, and analog front-end circuitry.
Which applications are better suited to the ADS7822U versus the ADS7804UB?
The ADS7822U is suited to portable, battery-powered, and space-constrained systems requiring low power and a serial interface, such as handheld instruments and remote sensors. The ADS7804UB is suited to industrial and instrumentation systems that require a complete parallel-interface ADC with an internal reference and a wide bipolar ±10 V input range, such as data acquisition cards and process control equipment.