Part A
ADS1254E
Texas Dụng cụ
- Lifecycle
- Active
- Stock
- 4308 PCS
- Package
- SSOP-20
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The ADS1254E and ADS1240E/1KG4 are both 24-bit delta-sigma ADCs from Texas Instruments sharing a compatible SOIC-20 footprint and similar supply architecture, but they differ in resolution architecture, input channel count, and interface timing. The ADS1254E offers a single-channel, high-speed 24-bit converter with a serial interface, while the ADS1240E/1KG4 provides a multi-channel 24-bit ADC with an SPI-compatible interface and on-chip PGA. Designers should validate channel count requirements, interface protocol, and reference configuration before substituting one for the other in a given application.
Resolution and Architecture
Validation required
Input Channel Count
Not compatible
Interface Protocol
Validation required
Package Type
High match
Parts at a glance
Part B
ADS1240E/1KG4
Texas Dụng cụ
- Lifecycle
- Active
- Stock
- 7122 PCS
- Package
- SSOP-24
- 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 | ADS1254E | ADS1240E/1KG4 | 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 | 4 (differential) | 4 (2 differential / 4 single-ended) | Channel configuration affects how many sensors can be connected and whether single-ended or differential measurements are supported. |
| Maximum sample rate (SPS) | 20k | 15 | Sample rate determines the bandwidth of signals that can be captured; the ADS1254E supports much faster sampling than the ADS1240E. |
| Interface | SPI (serial) | SPI (serial) | Both use a serial SPI interface, simplifying drop-in replacement from a digital communication standpoint. |
| Supply voltage (analog) | 5 V | 2.7 V to 5.25 V | Supply range affects compatibility with the system power rail; the ADS1240E supports lower-voltage operation. |
| PGA / gain stage | No (fixed gain) | Yes (PGA, gains 1–128) | An integrated PGA allows direct amplification of small sensor signals, which the ADS1254E lacks, affecting front-end design. |
| Package | SSOP-20 | SSOP-20 | Matching package footprint enables physical board compatibility for substitution. |
| Operating temperature range | -40°C to +85°C | -40°C to +85°C | Identical temperature ratings mean both suit the same industrial environments. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1254E | ADS1240E/1KG4 |
|---|---|---|
| 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 and ADS1240E?
The ADS1254E is a 24-bit delta-sigma ADC with a fixed input range and a maximum data rate of 20 kSPS, while the ADS1240E 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. The ADS1240E also includes a built-in input multiplexer and a low-noise PGA, whereas the ADS1254E does not integrate a PGA.
Are the ADS1254E and ADS1240E pin-compatible?
No. The ADS1254E is offered in a 20-pin SSOP package, while the ADS1240E is offered in a 24-pin SSOP package. The pin counts and pin functions differ, so they are not drop-in replacements for each other.
What is the maximum data rate of each device?
The ADS1254E supports a maximum data rate of 20 kSPS. The ADS1240E supports a maximum data rate of 15 kSPS. Both are delta-sigma converters, but the ADS1254E offers a higher maximum output rate.
Does the ADS1240E include a programmable gain amplifier?
Yes. The ADS1240E integrates a low-noise PGA with selectable gains of 1, 2, 4, 8, 16, 32, 64, and 128. The ADS1254E does not include an integrated PGA, so external signal conditioning is required for low-level signals.
What are the supply voltage requirements for these ADCs?
Both the ADS1254E and ADS1240E operate from a single 5 V analog supply (AVDD) and a 2.7 V to 5.25 V digital supply (DVDD). Designers should verify the exact recommended operating conditions in the respective manufacturer datasheets before finalizing the power supply design.
Which device is better suited for multi-channel sensor applications?
The ADS1240E is generally better suited for multi-channel sensor applications because it includes an input multiplexer and a PGA, allowing multiple low-level sensor signals to be switched and amplified without external components. The ADS1254E lacks these integrated features and is more appropriate for single-channel or externally multiplexed designs.
Can the ADS1254E and ADS1240E share the same external reference and clock configuration?
Both devices support an external voltage reference and can operate with an external clock source, but the reference input ranges and clock requirements may differ. The ADS1240E also supports a internal oscillator option in some variants, while the ADS1254E requires an external clock. The exact reference and clock specifications must be confirmed from the respective datasheets.
What is the difference in noise performance between the ADS1254E and ADS1240E?
Both are 24-bit delta-sigma ADCs with low-noise architectures, but their noise performance depends on data rate, gain setting, and reference configuration. The ADS1240E datasheet specifies noise performance at various PGA gains, while the ADS1254E specifies noise at its fixed input range. A direct comparison requires evaluating both datasheets under identical operating conditions.