Part A
ADS1240E
Texas Dụng cụ
- Lifecycle
- Active
- Stock
- 5619 PCS
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The ADS1254E/2K5 and ADS1240E are both 24-bit delta-sigma ADCs from Texas Instruments in a 20-pin SSOP package, sharing a comparable serial interface and supply architecture. However, they differ in resolution architecture, input channel configuration, and data rate capability, so the ADS1240E can serve as a functional substitute only after validating channel count, throughput, and input signal conditioning requirements against the target design.
Resolution and Architecture
High match
Input Channel Configuration
Validation required
Data Rate
Validation required
Package Type
High match
Parts at a glance
Part B
ADS1254E/2K5
Texas Dụng cụ
- Lifecycle
- Active
- Stock
- 4500 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 | ADS1254E/2K5 | ADS1240E | 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 (differential) | Channel count determines how many sensor inputs can be multiplexed without external switching. |
| Maximum sample rate (SPS) | 20k | 15 | The ADS1254 supports much higher throughput, which is critical for fast-changing signals; the ADS1240 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 ADS1240 offers a wider analog supply range, allowing operation in lower-voltage systems where the ADS1254 cannot be used. |
| PGA / gain stages | No integrated PGA | Integrated PGA (gain 1 to 128) | The ADS1240's programmable gain amplifier enables direct connection of low-level sensors without external amplification. |
| Package | SSOP-20 | SSOP-20 | Identical package and pin count simplify PCB layout compatibility between the two parts. |
| Operating temperature range | -40°C to +85°C | -40°C to +85°C | Matching industrial temperature ranges mean both are suitable for the same environmental conditions. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1240E | ADS1254E/2K5 |
|---|---|---|
| Part Status | Active | Active |
| Base Product Number | ADS1240 | - |
| Number of Bits | 24 | 24 |
| Sampling Rate (Per Second) | 15 | - |
| Number of Inputs | 4 | 4 |
| Input Type | Differential, Single Ended | Differential |
| Data Interface | SPI | SPI |
| Configuration | MUX-PGA-ADC | MUX-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 | - |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | - |
| Packaging | Tube | - |
| Sampling Rate(Per Second) | - | 20k |
| Number of A/D Converters | - | 1 |
Frequently asked questions
What are the key architectural differences between the ADS1254E/2K5 and the ADS1240E?
The ADS1254E/2K5 is a 24-bit delta-sigma ADC with a fixed gain of 1 and a maximum data rate of 20.8 kSPS, while the ADS1240E is a 24-bit delta-sigma ADC featuring a programmable gain amplifier (PGA) with selectable gains of 1 to 128 and a maximum data rate of 15 SPS. The ADS1254E/2K5 is supplied in a 20-pin QSOP package, whereas the ADS1240E is supplied in a 24-pin TSSOP package.
Are the ADS1254E/2K5 and ADS1240E pin-to-pin compatible?
No. The ADS1254E/2K5 uses a 20-pin QSOP package and the ADS1240E uses a 24-pin TSSOP package, so they have different pin counts, package dimensions, and PCB land patterns. They cannot be treated as pin-to-pin replacements.
How do the input configurations of the ADS1254E/2K5 and ADS1240E differ?
The ADS1254E/2K5 provides four differential input channels, while the ADS1240E provides two differential input channels (or four single-ended inputs). The ADS1240E additionally includes a PGA that allows low-level signals to be amplified before conversion, whereas the ADS1254E/2K5 has a fixed gain of 1.
How do the maximum data rates of the ADS1254E/2K5 and ADS1240E compare?
The ADS1254E/2K5 supports data rates up to 20.8 kSPS, making it suitable for higher-speed measurement applications. The ADS1240E supports data rates up to 15 SPS, which is oriented toward low-speed, high-resolution measurements such as temperature and bridge sensors.
Do the ADS1254E/2K5 and ADS1240E use the same digital interface?
No. The ADS1254E/2K5 uses a synchronous serial interface compatible with SPI, QSPI, and Microwire, with a dedicated DRDY output. The ADS1240E uses an SPI-compatible serial interface with separate DIN and DOUT lines and a DRDY output. The command sets and register maps differ between the two devices, so firmware must be adapted accordingly.
Can the ADS1254E/2K5 and ADS1240E operate from the same supply voltage?
Both devices operate from a single 5 V analog supply (AVDD) and a 2.7 V to 5.25 V digital supply (DVDD). However, the ADS1240E also supports a 2.7 V to 5.25 V analog supply range, giving it greater flexibility for low-voltage systems, while the ADS1254E/2K5 requires a 5 V analog supply.
Which device is better suited for low-level sensor signals such as thermocouples or bridge sensors?
The ADS1240E is generally better suited for low-level sensor signals because it integrates a PGA with gains up to 128 and supports low data rates that reduce noise. The ADS1254E/2K5 has a fixed gain of 1 and higher data rates, so external amplification would be required for very low-level signals.
What are the package and operating temperature range differences between the ADS1254E/2K5 and ADS1240E?
The ADS1254E/2K5 is offered in a 20-pin QSOP package, and the ADS1240E is offered in a 24-pin TSSOP package. Both devices are specified for the industrial temperature range of -40°C to +85°C.