Part A
ADS7822U
Texas Instruments
- Lifecycle
- Active
- Stock
- 7079 PCS
- Package
- SOIC-8
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The ADS7822U and ADS7812UB are both 12-bit successive-approximation ADCs from Texas Instruments, but they differ in resolution-critical parameters such as sampling rate, supply voltage range, and package footprint. The ADS7822U offers a higher throughput and a wider supply range, while the ADS7812UB provides a different interface and power profile. Designers should validate timing, reference, and layout compatibility before substituting one for the other in existing designs.
Resolution
High match
Sampling Rate
Validation required
Supply Voltage Range
Not compatible
Package Type
Validation required
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 | ADS7812UB | Why it matters |
|---|---|---|---|
| Resolution | 12 bit | 12 bit | Both are 12-bit ADCs, so nominal conversion resolution is equivalent for substitutability. |
| Sampling Rate | 200 kSPS | 40 kSPS | The ADS7822U supports a much higher throughput, which matters for faster signal acquisition requirements. |
| Input Type | Single-ended | Single-ended | Both accept single-ended inputs, so the input signal configuration is compatible. |
| Interface | SPI / Microwire / QSPI compatible serial | SPI / QSPI / Microwire compatible serial | Both use a serial interface, allowing similar digital host connections, though timing and protocol details differ. |
| Supply Voltage | 2.7 V to 5.25 V | 5 V (single supply) | The ADS7822U supports lower supply voltages, enabling use in low-voltage systems where the ADS7812UB cannot operate. |
| Package | SOIC-8 | SOIC-16 | Different package footprints and pin counts prevent direct drop-in board replacement. |
| Reference | External reference | External reference | Both require an external reference, so reference design considerations are similar. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Equivalent industrial temperature ranges mean both suit the same environmental conditions. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7822U | ADS7812UB |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Part Status | Active | Active |
| Number of Bits | 12 | 12 |
| Sampling Rate(Per Second) | 200k | 40k |
| Number of Inputs | 1 | 1 |
| Input Type | Pseudo-Differential | Single Ended |
| Data Interface | SPI | 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 | 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 ADS7812UB?
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 ADS7812UB is a 12-bit, 40-kSPS sampling ADC with a successive-approximation register architecture, a single-ended input, and a parallel interface, typically supplied in an SOIC-28 package. The two devices differ in resolution-adjacent parameters such as throughput, input configuration, and digital interface type.
Can the ADS7822U and ADS7812UB be used interchangeably in an existing design?
No. The ADS7822U and ADS7812UB differ in package footprint (SOIC-8 versus SOIC-28), digital interface (serial versus parallel), input configuration (pseudo-differential versus single-ended), and maximum sampling rate (200 kSPS versus 40 kSPS). A direct drop-in substitution is not possible without redesigning the PCB, interface logic, and timing.
How do the sampling rates of the ADS7822U and ADS7812UB compare?
The ADS7822U supports a maximum throughput of 200 kSPS, while the ADS7812UB supports a maximum throughput of 40 kSPS. Designs requiring higher sample rates should account for this five-fold difference when selecting between the two parts.
What digital interfaces do the ADS7822U and ADS7812UB provide?
The ADS7822U provides a serial interface compatible with SPI, QSPI, and Microwire, reducing pin count and board routing. The ADS7812UB provides a parallel interface for direct connection to a microprocessor bus. The interface choice affects firmware, host controller selection, and PCB layout.
How do the input configurations of the ADS7822U and ADS7812UB differ?
The ADS7822U features a pseudo-differential input, allowing it to reject common-mode signals within its specified input range. The ADS7812UB uses a single-ended input configuration. The appropriate choice depends on the signal source topology and common-mode conditions in the target application.
Do the ADS7822U and ADS7812UB differ in power consumption?
Yes. The ADS7822U is specified as a micropower device optimized for low-power and battery-operated systems, while the ADS7812UB is a higher-speed parallel-interface converter with correspondingly different supply current requirements. Designers should consult the respective manufacturer datasheets for exact supply current and power figures under their intended operating conditions.
What package options are available for the ADS7822U and ADS7812UB?
The ADS7822U is offered in an SOIC-8 package, while the ADS7812UB is offered in an SOIC-28 package. The significant difference in pin count and footprint means the two devices are not mechanically or layout compatible.
Which device is better suited for low-power portable applications?
The ADS7822U is generally the more suitable choice for low-power portable applications because it is specified as a micropower 12-bit ADC with a serial interface that minimizes pin count and host overhead. The ADS7812UB, with its parallel interface and higher pin count, is oriented toward bus-connected systems where throughput and direct processor interfacing are prioritized.