Part A
ADS1254E/2K5
Texas Instruments
- Lifecycle
- Active
- Stock
- 4500 PCS
- Package
- SSOP-20
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (ADC)
Replacement verdict
Not a drop-in replacement
The ADS1254E/2K5 and ADS1240EG4 are not drop-in replacements for each other. Although both are 24-bit delta-sigma analog-to-digital converters from Texas Instruments, they differ in resolution architecture, input channel configuration, package footprint, and reference/supply requirements, so a direct board-level substitution is not possible without redesign.
Different channel count
Different package footprint
Different input configuration
Different reference architecture
Parts at a glance
Part B
ADS1240EG4
Texas Instruments
- Lifecycle
- Active
- Stock
- 7995 PCS
- Package
- SSOP-24
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (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 | ADS1254E/2K5 | ADS1240EG4 | Why it matters |
|---|---|---|---|
| Resolution (bits) | 24 | 24 | Both are 24-bit delta-sigma ADCs, so resolution alone does not distinguish them for substitutability. |
| Number of input channels | 4 (differential) | 4 (2 differential / 4 single-ended) | Channel count and configuration determine how many signals can be measured and whether single-ended or differential inputs are supported. |
| Maximum sample rate (SPS) | 20k | 15 | Sample rate sets the bandwidth and speed of the measurement; a large difference affects suitability for fast vs. high-resolution slow signals. |
| Interface | SPI (serial) | SPI (serial) | Both use a serial SPI interface, so the host microcontroller connection is compatible. |
| Supply voltage (analog) | 5 V | 2.7 V to 5.25 V | Supply range affects compatibility with the system power rail and allowable input signal range. |
| PGA / gain | No integrated PGA | Integrated PGA (gain 1 to 128) | An integrated PGA allows direct amplification of small signals, reducing external components and improving low-level measurement accuracy. |
| Package | SSOP-20 | SSOP-20 | Package compatibility determines whether the part can be dropped into the same PCB footprint. |
| Operating temperature range | -40°C to +85°C | -40°C to +85°C | Temperature range confirms suitability for industrial and extended-environment applications. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1254E/2K5 | ADS1240EG4 |
|---|---|---|
| Supplier | - | Texas Instruments |
| Part Status | Active | Discontinued at Digi-Key |
| Number of Bits | 24 | 24 |
| Sampling Rate(Per Second) | 20k | 15 |
| Number of Inputs | 4 | 4 |
| Input Type | Differential | Differential, Single Ended |
| Data Interface | SPI | SPI |
| Configuration | MUX-ADC | MUX-PGA-ADC |
| Number of A/D Converters | 1 | 1 |
| Architecture | Sigma-Delta | Sigma-Delta |
| Reference Type | External | External |
| Voltage - Supply, Analog | 5V | 2.7V ~ 3.3V, 5V |
| Voltage - Supply, Digital | 1.8V ~ 3.6V | 2.7V ~ 5.25V |
| Features | - | PGA |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key architectural differences between the ADS1254E/2K5 and the ADS1240EG4?
The ADS1254E/2K5 is a 24-bit delta-sigma ADC with a fixed gain of 1 and a maximum data rate of 20 kSPS, housed in a 20-pin SSOP package. The ADS1240EG4 is a 24-bit delta-sigma ADC featuring a programmable gain amplifier (PGA) with gains from 1 to 128 and a maximum data rate of 15 kSPS, housed in a 24-pin TSSOP package. The ADS1240EG4 integrates a PGA and a more flexible input multiplexer, while the ADS1254E/2K5 is a simpler, higher-speed fixed-gain device.
Are the ADS1254E/2K5 and ADS1240EG4 pin-compatible or package-compatible?
No. The ADS1254E/2K5 uses a 20-pin SSOP package, while the ADS1240EG4 uses a 24-pin TSSOP package. The pin counts, package dimensions, and pin functions differ, so they are not drop-in replacements and require different PCB land patterns.
Which device offers a higher maximum data rate?
The ADS1254E/2K5 supports a maximum data rate of 20 kSPS, while the ADS1240EG4 supports a maximum data rate of 15 kSPS. The ADS1254E/2K5 therefore provides a higher throughput for applications requiring faster sampling.
Does the ADS1240EG4 include a programmable gain amplifier (PGA)?
Yes. The ADS1240EG4 integrates a PGA with selectable gains of 1, 2, 4, 8, 16, 32, 64, and 128, allowing direct amplification of low-level sensor signals. The ADS1254E/2K5 does not include a PGA and operates with a fixed gain of 1.
What are the supply voltage requirements for each device?
Both devices operate from a single 5 V analog supply (AVDD) and a 2.7 V to 5.25 V digital supply (DVDD), consistent with the Texas Instruments datasheets for the ADS1254 and ADS1240 families. Designers should verify the exact supply range in the respective datasheet revision before finalizing the power design.
Can the ADS1254E/2K5 and ADS1240EG4 be used interchangeably in an existing design?
No. Differences in package footprint, pin count, PGA availability, data rate, and input multiplexer configuration prevent direct interchangeability. A redesign of the PCB layout and firmware configuration would be required to substitute one for the other.
Which device is better suited for low-level sensor applications requiring gain?
The ADS1240EG4 is better suited for low-level sensor applications because its integrated PGA provides gains up to 128, enabling direct connection of low-output sensors such as thermocouples or bridge transducers. The ADS1254E/2K5, with fixed gain of 1, would require external amplification for such low-level signals.