Part A
ADS1240E
Texas Instruments
- Lifecycle
- Active
- Stock
- 5619 PCS
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The ADS1255IDBR and ADS1240E are both 24-bit delta-sigma ADCs from Texas Instruments sharing a compatible functional architecture, but they differ in resolution-related performance, package footprint, and channel configuration. The ADS1255IDBR offers higher resolution and a wider feature set, while the ADS1240E provides a simpler single-channel solution. Designers should validate package compatibility and channel requirements before substituting, as the two parts are not pin-for-pin drop-in equivalents.
Resolution and Data Rate
Validation required
Package Type
Validation required
Channel Count
Validation required
Supply Voltage Range
High match
Parts at a glance
Part B
ADS1255IDBR
Texas Instruments
- Lifecycle
- Active
- Stock
- 2109 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 | ADS1255IDBR | ADS1240E | Why it matters |
|---|---|---|---|
| Resolution (bits) | 24 | 24 | Both are 24-bit delta-sigma ADCs, so resolution alone does not differentiate them for substitutability. |
| Number of input channels | 2 (differential) / 1 (differential) | 4 (differential) / 8 (single-ended) | Channel count determines how many signals can be measured; the ADS1240E supports more inputs, affecting system architecture. |
| Maximum sample rate (SPS) | 30k | 15 | Sample rate dictates the bandwidth of signals that can be captured; the ADS1255 is far faster, suiting higher-speed acquisition. |
| PGA gain range | 1 to 64 | 1 to 128 | Programmable gain affects the smallest resolvable input signal; the ADS1240E offers higher gain for low-level sensors. |
| Interface | SPI | SPI | Both use SPI, so the digital host interface is compatible for direct substitution. |
| Supply voltage (analog) | 5 V | 2.7 V to 5.25 V | Supply range affects compatibility with system power rails; the ADS1240E supports lower-voltage operation. |
| Package | SSOP-20 | SSOP-20 | Identical package allows drop-in PCB footprint compatibility. |
| Operating temperature range | -40°C to +85°C | -40°C to +85°C | Matching temperature ranges ensure equivalent environmental robustness for industrial 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 | ADS1240E | ADS1255IDBR |
|---|---|---|
| Part Status | Active | Active |
| Base Product Number | ADS1240 | - |
| Number of Bits | 24 | 24 |
| Sampling Rate (Per Second) | 15 | - |
| Number of Inputs | 4 | 1, 2 |
| Input Type | Differential, Single Ended | Differential, Single Ended |
| Data Interface | SPI | SPI |
| Configuration | MUX-PGA-ADC | MUX-PGA-ADC |
| Number of A / D Converters | 1 | - |
| Architecture | Sigma-Delta | Sigma-Delta |
| Reference Type | External | External |
| Voltage - Supply, Analog | 2.7V ~ 3.3V, 5V | 5V |
| Voltage - Supply, Digital | 2.7V ~ 5.25V | 1.8V ~ 3.6V |
| Features | PGA | PGA |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | - |
| Packaging | Tube | - |
| Sampling Rate(Per Second) | - | 30k |
| Number of A/D Converters | - | 1 |
Frequently asked questions
What are the primary differences between the ADS1255IDBR and the ADS1240E?
The ADS1255IDBR is a 24-bit delta-sigma ADC with a maximum data rate of 30 kSPS, featuring a single-channel differential input, SPI interface, and a 20-pin SSOP package. The ADS1240E is a 24-bit delta-sigma ADC with a maximum data rate of 15 SPS, featuring a 4-channel differential input multiplexer, SPI interface, and a 28-pin TSSOP package. The ADS1255IDBR targets higher-speed precision measurement, while the ADS1240E targets low-speed multi-channel sensor applications.
Are the ADS1255IDBR and ADS1240E pin-to-pin compatible?
No. The ADS1255IDBR is supplied in a 20-pin SSOP package, while the ADS1240E is supplied in a 28-pin TSSOP package. The pin counts, package dimensions, and pin functions differ, so they are not directly interchangeable on the same PCB footprint.
How do the maximum data rates of the ADS1255IDBR and ADS1240E compare?
The ADS1255IDBR supports a maximum data rate of 30 kSPS (30,000 samples per second). The ADS1240E supports a maximum data rate of 15 SPS. The ADS1255IDBR is therefore suitable for higher-speed precision acquisition, while the ADS1240E is intended for low-speed, high-resolution measurements.
How many input channels does each device provide?
The ADS1255IDBR provides a single differential input channel (one input pair). The ADS1240E includes a 4-channel differential input multiplexer, allowing selection among four differential input pairs. The ADS1240E is better suited for multi-sensor systems requiring channel switching.
Do both devices use the same digital interface?
Both devices use an SPI-compatible serial interface for communication with a host microcontroller. However, register maps, command sets, and timing specifications differ between the two devices, so firmware must be adapted accordingly when migrating between them.
What are the supply voltage requirements for the ADS1255IDBR and ADS1240E?
Both devices operate from a single 5 V analog supply (AVDD) with a separate digital supply (DVDD) in the 1.8 V to 3.6 V range, consistent with their respective manufacturer datasheets. Designers should verify the exact recommended operating conditions in the official datasheets before finalizing power supply designs.
Can the ADS1255IDBR directly replace the ADS1240E in an existing design?
No. Direct replacement is not possible due to differences in package (20-pin SSOP vs 28-pin TSSOP), channel count (single differential vs 4-channel differential multiplexer), maximum data rate (30 kSPS vs 15 SPS), and register/command set. A redesign of the PCB footprint and firmware is required.