Part A
ADS1256IDBR
Texas Dụng cụ
- Lifecycle
- Active
- Stock
- 4327 PCS
- Package
- SSOP-28
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Not a drop-in replacement
The ADS1256IDBR and ADS1254WDBQEP are not drop-in replacements for one another. They differ in resolution, channel architecture, digital interface, and package footprint, so substituting one for the other requires board-level redesign and firmware changes rather than a direct swap.
Different resolution
Different channel architecture
Different digital interface
Different package footprint
Parts at a glance
Part B
ADS1254WDBQEP
Texas Dụng cụ
- Lifecycle
- Active
- Stock
- 7746 PCS
- Package
- SSOP-20
- Series
- Data Acquisition - 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 | ADS1256IDBR | ADS1254WDBQEP | Why it matters |
|---|---|---|---|
| Resolution (bits) | 24 | 20 | Higher resolution provides finer measurement granularity; a 24-bit ADC can resolve much smaller signal changes than a 20-bit device, affecting precision-critical applications. |
| Number of input channels | 8 (single-ended) / 4 (differential) | 4 (differential) | Channel count determines how many signals can be measured without external multiplexing; fewer channels may require added circuitry for multi-sensor systems. |
| Maximum sample rate (SPS) | 30k | 20k | Sample rate limits the bandwidth of signals that can be captured; a lower rate may be insufficient for fast-changing or multiplexed inputs. |
| Interface type | SPI | SPI | Both use SPI, so the host microcontroller interface is compatible, easing drop-in substitution from a digital communication standpoint. |
| Supply voltage (analog) | 5 V | 5 V | Matching analog supply simplifies power rail design and ensures comparable input voltage range compatibility. |
| Package / mounting | 28-SSOP (surface mount) | 20-SSOP (surface mount) | Different package footprints and pin counts mean the PCB layout must be redesigned; they are not physically drop-in compatible. |
| Operating temperature range | -40°C to +85°C | -55°C to +125°C | The extended temperature range of the QEP-grade part suits harsher environments, while the standard part is limited to commercial/industrial conditions. |
| Input type | Single-ended and differential | Differential only | Single-ended capability allows direct measurement of ground-referenced signals; a differential-only device may need additional signal conditioning. |
| Qualification / grade | Standard industrial | Enhanced product (EP), Q-grade | The enhanced-product grade indicates tighter screening and wider temperature support, relevant for rugged or defense/aerospace applications. |
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 | ADS1256IDBR | ADS1254WDBQEP |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC,Texas Instruments |
| Part Status | Active | Obsolete |
| Number of Bits | 24 | 24 |
| Sampling Rate(Per Second) | 30k | 20k |
| Number of Inputs | 4, 8 | 4 |
| Input Type | Differential, Single Ended | Differential |
| Data Interface | SPI | SPI |
| Configuration | MUX-PGA-ADC | MUX-ADC |
| Number of A/D Converters | 1 | 1 |
| Architecture | Sigma-Delta | Sigma-Delta |
| Reference Type | External | External |
| Voltage - Supply, Analog | 5V | 5V |
| Voltage - Supply, Digital | 1.8V ~ 3.6V | 1.8V ~ 3.6V |
| Operating Temperature | -40°C ~ 85°C | -55°C ~ 115°C (TA) |
| Features | PGA | - |
Frequently asked questions
What are the primary differences between the ADS1256IDBR and the ADS1254WDBQEP?
The ADS1256IDBR is a 24-bit, 8-channel delta-sigma ADC with a maximum data rate of 30 kSPS, housed in a 28-pin SSOP package, and specified over the -40°C to +85°C temperature range. The ADS1254WDBQEP is a 24-bit, 4-channel delta-sigma ADC with a maximum data rate of 20 kSPS, supplied in a 20-pin SSOP package, and is a Q100-qualified automotive-grade device specified over the -40°C to +125°C temperature range.
Are the ADS1256IDBR and ADS1254WDBQEP pin-to-pin or package compatible?
No. The ADS1256IDBR uses a 28-pin SSOP package while the ADS1254WDBQEP uses a 20-pin SSOP package. The pin counts and pin functions differ, so they are not drop-in replacements and require different PCB footprints.
How do the input channel counts of the two ADCs compare?
The ADS1256IDBR provides 8 single-ended inputs (or 4 differential inputs) via an input multiplexer. The ADS1254WDBQEP provides 4 single-ended inputs (or 2 differential inputs). Designs requiring more channels should account for this difference.
What are the maximum data rates of the ADS1256IDBR and ADS1254WDBQEP?
The ADS1256IDBR supports data rates up to 30 kSPS. The ADS1254WDBQEP supports data rates up to 20 kSPS. Both are delta-sigma converters with programmable output rates, but the ADS1256IDBR offers a higher maximum throughput.
Do both devices support the same digital interface?
Both devices use an SPI-compatible serial interface for communication with a host controller. However, register maps, command sets, and configuration details differ between the two parts, so firmware must be adapted accordingly.
What are the operating temperature ranges for each device?
The ADS1256IDBR is specified over -40°C to +85°C. The ADS1254WDBQEP is specified over -40°C to +125°C, reflecting its automotive Q100 qualification and suitability for higher-temperature environments.
Can the ADS1254WDBQEP be used as a substitute for the ADS1256IDBR in an existing design?
Not directly. The devices differ in package, pin count, channel count, maximum data rate, and temperature rating. A substitution requires a PCB redesign, firmware changes, and validation against the target application requirements using the respective manufacturer datasheets.