Part A
ADS1254E
德州儀器
- Lifecycle
- Active
- Stock
- 4308 件
- Package
- SSOP-20
- Series
- 資料獲取-模數轉換器（ADC）
Replacement verdict
Not a drop-in replacement
The ADS1254E and ADS1240EG4 are both 24-bit delta-sigma ADCs from Texas Instruments, but they differ in resolution architecture, input channel configuration, package footprint, and interface timing, so the ADS1240EG4 cannot be used as a direct drop-in substitute for the ADS1254E without redesign and revalidation.
Different channel count
Different package footprint
Different interface timing
Different reference architecture
Parts at a glance
Part B
ADS1240EG4
德州儀器
- Lifecycle
- Active
- Stock
- 7995 件
- Package
- SSOP-24
- Series
- 資料獲取-模數轉換器（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 | ADS1240EG4 | 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 (differential) | Channel count determines how many sensor inputs can be multiplexed without external circuitry. |
| Maximum sample rate (SPS) | 19.2k | 15 | The ADS1254E supports much higher throughput, which matters for fast-changing signals; the ADS1240EG4 is limited to low-speed precision measurements. |
| Interface | SPI (serial) | SPI (serial) | Both use a serial SPI-compatible interface, easing drop-in replacement at the digital side. |
| Supply voltage (analog) | 5 V | 2.7 V to 5.25 V | The wider analog supply range of the ADS1240EG4 allows operation in lower-voltage systems where the ADS1254E cannot be used. |
| PGA (programmable gain amplifier) | No | Yes (gain 1 to 128) | The integrated PGA on the ADS1240EG4 enables direct connection of low-level sensors without external amplification. |
| Package | SSOP-20 | SSOP-28 | Different package footprints and pin counts prevent direct board-level substitution without layout changes. |
| Operating temperature range | -40°C to +85°C | -40°C to +85°C | Identical temperature ratings mean both suit the same industrial environments. |
| Input type | Differential | Differential | Both accept differential inputs, providing common-mode noise rejection for precision measurements. |
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 | ADS1254E | 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 and the ADS1240EG4?
The ADS1254E 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 with a programmable gain amplifier (PGA) offering gains from 1 to 128, a maximum data rate of 15 kSPS, and is supplied in a 24-pin SSOP package. The ADS1240EG4 integrates a PGA and a more flexible input multiplexer, while the ADS1254E is a simpler fixed-gain converter.
Are the ADS1254E and ADS1240EG4 pin-to-pin compatible?
No. The ADS1254E is packaged in a 20-pin SSOP, whereas the ADS1240EG4 uses a 24-pin SSOP. The different pin counts and pin assignments mean the two devices are not drop-in replacements and require different PCB footprints.
Which device offers a higher maximum data rate?
The ADS1254E supports a maximum data rate of 20 kSPS, while the ADS1240EG4 supports a maximum data rate of 15 kSPS. The ADS1254E therefore provides a higher maximum throughput, whereas the ADS1240EG4 trades some speed for integrated programmable gain.
Does the ADS1240EG4 include a programmable gain amplifier while the ADS1254E does not?
Yes. The ADS1240EG4 integrates a PGA with selectable gains of 1, 2, 4, 8, 16, 32, 64, and 128, allowing direct interfacing with low-level sensors. The ADS1254E has a fixed gain of 1 and does not include a programmable gain stage, so external amplification is required for small-signal inputs.
How do the input multiplexer configurations compare between the two ADCs?
The ADS1240EG4 provides a flexible input multiplexer that supports differential and single-ended input configurations across multiple channels. The ADS1254E offers a more limited input structure with fewer selectable input channels. Designers needing multi-channel flexibility should verify the exact channel count and configuration in the respective datasheets.
What are the supply voltage and reference requirements for these devices?
Both devices operate from a single 5 V analog supply and support an external reference voltage. The ADS1240EG4 also provides a buffered reference input option. Exact reference voltage ranges and digital supply requirements should be confirmed against the manufacturer datasheets for each part before finalizing a design.
Which device is better suited for low-level sensor applications?
The ADS1240EG4 is generally better suited for low-level sensor applications because its integrated PGA allows gains up to 128, enabling direct amplification of small differential signals. The ADS1254E, with fixed gain of 1, requires external amplification for low-amplitude sensor outputs.
Can the ADS1254E and ADS1240EG4 be used interchangeably in an existing design?
No. Differences in package pin count (20-pin vs 24-pin SSOP), input multiplexer configuration, PGA availability, and maximum data rate (20 kSPS vs 15 kSPS) prevent direct interchangeability. Any substitution requires a full review of the schematic, PCB layout, and firmware against the target device datasheet.