Part A
ADS7822U
Texas Instruments
- Lifecycle
- Active
- Stock
- 7079 PCS
- Package
- SOIC-8
- Series
- Acquisition de données - Convertisseur analogique - numérique (ADC)
Replacement verdict
Not a drop-in replacement
The ADS7822U and ADS7825UB/1K are not drop-in replacements for one another. The ADS7822U is a single-channel 12-bit SAR ADC in a small SOIC-8 package, while the ADS7825UB/1K is a 4-channel 16-bit SAR ADC in a wider SOIC-28 package with a different serial interface and reference architecture. Designers must account for differences in resolution, channel count, package footprint, and digital interface before considering any substitution.
Different resolution
Different channel count
Different package footprint
Different digital interface
Parts at a glance
Part B
ADS7825UB/1K
Texas Instruments
- Lifecycle
- Active
- Stock
- 4144 PCS
- Package
- SOIC-28
- Series
- Acquisition de données - Convertisseur analogique - numérique (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 | ADS7825UB/1K | Why it matters |
|---|---|---|---|
| Resolution | 12 bit | 16 bit | Resolution determines the smallest measurable signal step; a 16-bit ADC provides 16x finer quantization than a 12-bit device, affecting measurement accuracy. |
| Number of Input Channels | 1 (single-ended) | 4 (single-ended) | Channel count defines how many analog signals can be digitized; the ADS7825UB can multiplex four inputs while the ADS7822U handles only one. |
| Sampling Rate | 75 kSPS | 40 kSPS | Maximum throughput limits the bandwidth of signals that can be captured; the ADS7822U samples faster while the ADS7825UB trades speed for higher resolution. |
| Interface Type | SPI (serial) | Parallel | The digital interface must match the host controller; SPI uses fewer pins while parallel offers higher data throughput and simpler timing. |
| Supply Voltage | 2.7 V to 5.25 V | 5 V (±5%) | Supply range affects compatibility with low-voltage logic and battery-powered systems; the ADS7822U supports wider low-voltage operation. |
| Package / Mounting | 8-SOIC (surface mount) | 28-SOIC (surface mount) | Package footprint and pin count determine PCB layout compatibility; the two parts are not drop-in replacements due to different package sizes. |
| Input Type | Single-ended | Single-ended (4-channel mux) | Input configuration affects how signals are connected; the ADS7825UB includes an on-chip multiplexer for multiple sources. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Temperature range indicates suitability for industrial environments; both parts share the same industrial-grade range. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7822U | ADS7825UB/1K |
|---|---|---|
| Supplier | - | Texas Instruments,Rochester Electronics, LLC |
| Part Status | Active | Active |
| Number of Bits | 12 | 16 |
| Sampling Rate(Per Second) | 200k | 40k |
| Number of Inputs | 1 | 4 |
| Input Type | Pseudo-Differential | Single Ended |
| Data Interface | SPI | 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 the ADS7825UB/1K?
The ADS7822U is a 12-bit, single-channel, micropower successive-approximation register (SAR) analog-to-digital converter (ADC) that communicates via a serial (SPI-compatible) interface. The ADS7825UB/1K is a 16-bit, four-channel (with a 4-to-1 multiplexer) SAR ADC that includes a parallel data interface and an internal reference. The ADS7825UB/1K offers higher resolution and more input channels, while the ADS7822U is a smaller, single-channel device.
Do the ADS7822U and ADS7825UB/1K have the same resolution and sampling rate?
No. The ADS7822U provides 12-bit resolution with a maximum sampling rate of 75 kSPS. The ADS7825UB/1K provides 16-bit resolution with a maximum sampling rate of 40 kSPS. The ADS7822U offers higher throughput at lower resolution, while the ADS7825UB/1K offers higher resolution at a lower throughput.
Are the ADS7822U and ADS7825UB/1K pin-to-pin or package compatible?
No. The ADS7822U is supplied in an 8-pin SOIC (D) package. The ADS7825UB/1K is supplied in a 28-pin SOIC (DW) package. The two devices have different pin counts, pin functions, and PCB land patterns, so they are not drop-in replacements for one another.
How do the digital interfaces of the ADS7822U and ADS7825UB/1K differ?
The ADS7822U uses a serial interface compatible with SPI, QSPI, and Microwire, requiring fewer host pins. The ADS7825UB/1K uses a parallel data interface for direct connection to a microprocessor bus. The interface choice affects host controller selection, PCB routing, and firmware design.
Do both devices include an internal voltage reference?
No. The ADS7822U requires an external reference voltage applied to its VREF pin. The ADS7825UB/1K includes an internal reference, though it also supports an external reference. Designs using the ADS7822U must provide a suitable external reference, whereas the ADS7825UB/1K can operate with its internal reference.
How do the power supply requirements and power consumption compare?
The ADS7822U operates from a single 2.7 V to 5.25 V supply and is specified for micropower operation, drawing approximately 0.54 mW at 75 kSPS with a 2.7 V supply. The ADS7825UB/1K operates from a 5 V supply and consumes more power due to its higher resolution, multiplexer, and internal reference. The ADS7822U is better suited to low-power, battery-operated designs.
Can the ADS7822U and ADS7825UB/1K be used interchangeably in an existing design?
No. Differences in resolution, number of input channels, package and pinout, digital interface (serial versus parallel), and reference architecture (external versus internal) prevent direct interchangeability. A redesign of the PCB, host interface, and firmware would be required to substitute one device for the other.