Part A
ADS1255IDBR
Texas Instruments
- Lifecycle
- Active
- Stock
- 2109 PCS
- Package
- SSOP-20
- Series
- Acquisition de données - Convertisseur analogique - numérique (ADC)
Replacement verdict
Not a drop-in replacement
The ADS1255IDBR and ADS1254WDBQEP differ fundamentally in resolution, channel architecture, and digital interface, so the ADS1254WDBQEP cannot serve as a direct substitute for the ADS1255IDBR in existing designs. The ADS1255IDBR offers 24-bit resolution with a single differential input and SPI interface, while the ADS1254WDBQEP provides 20-bit resolution with a 4-channel differential multiplexer and a different serial interface, requiring board-level redesign and firmware changes for any migration.
Different resolution
Different channel count
Different digital interface
Different package footprint
Parts at a glance
Part B
ADS1254WDBQEP
Texas Instruments
- Lifecycle
- Active
- Stock
- 7746 PCS
- Package
- SSOP-20
- 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 | ADS1255IDBR | ADS1254WDBQEP | Why it matters |
|---|---|---|---|
| Resolution (bits) | 24 | 20 | Higher resolution provides finer measurement granularity; a 24-bit ADC resolves smaller signal changes than a 20-bit device, affecting precision-critical applications. |
| Number of input channels | 2 (differential) | 4 (differential) | Channel count determines how many independent signals can be measured; the ADS1254 offers more differential inputs for multi-sensor designs. |
| Maximum sample rate (SPS) | 30k | 20k | Sample rate sets the maximum signal bandwidth that can be captured; higher rates suit faster-changing signals and higher-frequency measurements. |
| Interface type | SPI (serial) | SPI (serial) | Both use SPI, but the ADS1255 supports a wider command set and register configuration, while the ADS1254 uses a simpler read-only interface, affecting firmware compatibility. |
| Supply voltage (analog) | 5 V (single 5 V analog supply) | 5 V (single 5 V analog supply) | Analog supply voltage must match the signal range and reference; both operate from 5 V, but the ADS1255 offers more flexible reference and PGA configuration. |
| Programmable gain amplifier (PGA) | Yes (1 to 64) | No | An integrated PGA allows direct amplification of small signals without external circuitry; the ADS1255 can measure low-level sensors directly, while the ADS1254 requires external gain stages. |
| Package type | SSOP-20 (DB) | SSOP-20 (DBQ) | Package footprint and pinout affect PCB layout and drop-in compatibility; both are 20-pin SSOP variants but differ in thermal and mechanical specifications. |
| Operating temperature range | -40°C to +85°C | -40°C to +125°C | The extended temperature range of the ADS1254WDBQEP (enhanced product) suits harsher environments, while the ADS1255 targets standard industrial conditions. |
| Qualification / product grade | Standard industrial | Enhanced product (EP), Q100-grade | Enhanced-product qualification indicates tighter testing and reliability screening for demanding applications; the standard grade is intended for general industrial use. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1255IDBR | 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 | 1, 2 | 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 key architectural differences between the ADS1255IDBR and the ADS1254WDBQEP?
The ADS1255IDBR is a 24-bit delta-sigma ADC with a single channel and a programmable gain amplifier (PGA), supporting data rates up to 30 kSPS. The ADS1254WDBQEP is a 24-bit delta-sigma ADC with four differential input channels (multiplexed) and a fixed gain of 1, supporting data rates up to 20 kSPS. The ADS1255IDBR includes an SPI-compatible serial interface and a PGA with gains from 1 to 64, while the ADS1254WDBQEP does not include a PGA.
Are the ADS1255IDBR and ADS1254WDBQEP pin-compatible or package-compatible?
No. The ADS1255IDBR is supplied in a 20-pin SSOP (DB) package, while the ADS1254WDBQEP is supplied in a 20-pin QSOP (DBQ) package. Although both are 20-pin packages, the pin functions and PCB land patterns differ, so they are not drop-in replacements for each other.
What are the input channel configurations of each device?
The ADS1255IDBR provides a single differential input channel (or two single-ended inputs) with a PGA. The ADS1254WDBQEP provides four differential input channels that are internally multiplexed, with a fixed gain of 1 and no PGA.
How do the maximum data rates compare between the ADS1255IDBR and ADS1254WDBQEP?
The ADS1255IDBR supports programmable data rates up to 30 kSPS. The ADS1254WDBQEP supports data rates up to 20 kSPS. Both are delta-sigma converters, so effective resolution decreases as data rate increases.
Do both devices support the same digital interface?
Both devices use an SPI-compatible serial interface for configuration and data readout. However, the register maps and command sets differ between the ADS1255IDBR and the ADS1254WDBQEP, so firmware must be adapted accordingly.
What are the supply voltage requirements for each part?
The ADS1255IDBR operates from a single 5 V analog supply (AVDD) and a 1.8 V to 3.6 V digital supply (DVDD). The ADS1254WDBQEP operates from a single 5 V analog supply and a 2.7 V to 5.25 V digital supply. Designers should verify exact limits against the respective manufacturer datasheets.
Can the ADS1255IDBR and ADS1254WDBQEP be used interchangeably in an existing design?
No. Differences in package footprint, channel count, PGA availability, register map, and supply requirements mean the two devices are not interchangeable without schematic, layout, and firmware changes. A direct substitution is not supported.