Part A
ADS1256IDBR
Texas Instruments
- Lifecycle
- Active
- Stock
- 4327 Stückzahl
- Package
- SSOP-28
- Series
- Datenerfassung mit Analog to Digital Converters (ADC)
Replacement verdict
Not a drop-in replacement
The ADS1256IDBR and ADS1240E/1KG4 are both 24-bit delta-sigma ADCs, but they differ fundamentally in resolution architecture, channel count, interface type, and package footprint. The ADS1256IDBR offers 8 single-ended or 4 differential inputs with an SPI interface in a TSSOP-28 package, while the ADS1240E/1KG4 provides 2 differential inputs with a serial interface in a SSOP-20 package. These differences in channel count, package, and interface make them non-interchangeable without significant board redesign.
Different channel count
Different package footprint
Different interface type
Different input configuration
Parts at a glance
Part B
ADS1240E/1KG4
Texas Instruments
- Lifecycle
- Active
- Stock
- 7122 Stückzahl
- Package
- SSOP-24
- Series
- Datenerfassung mit 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 | ADS1256IDBR | 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 | 8 (single-ended) / 4 (differential) | 4 (single-ended) / 2 (differential) | Channel count determines how many signals can be multiplexed into one ADC; the ADS1256 supports twice as many inputs. |
| Maximum sample rate (SPS) | 30k | 15 | Sample rate sets the achievable signal bandwidth; the ADS1256 is far faster, which matters for higher-frequency or multiplexed measurements. |
| Interface | SPI | SPI | Both use a serial SPI interface, so host-side firmware and bus wiring are broadly compatible. |
| Supply voltage (analog) | 5 V (single 5 V analog supply) | 2.7 V to 5.25 V | Analog supply range affects compatibility with low-voltage systems; the ADS1240 is more flexible across supply rails. |
| PGA gain range | 1 to 64 | 1 to 128 | Programmable gain determines the smallest resolvable input signal; the ADS1240 offers higher gain for low-level sensors. |
| Package | SSOP-28 | SSOP-28 | Identical package and pin count simplify PCB footprint reuse when swapping parts. |
| Operating temperature range | -40°C to +85°C | -40°C to +85°C | Matching temperature ratings mean both suit the same industrial environments. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1256IDBR | ADS1240E/1KG4 |
|---|---|---|
| Supplier | - | Texas Instruments |
| Part Status | Active | Discontinued at Digi-Key |
| Number of Bits | 24 | 24 |
| Sampling Rate(Per Second) | 30k | 15 |
| Number of Inputs | 4, 8 | 4 |
| 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 | 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 | PGA |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key architectural differences between the ADS1256IDBR and the ADS1240E/1KG4?
The ADS1256IDBR is a 24-bit delta-sigma ADC with a 4-channel differential input multiplexer, programmable gain amplifier, and a maximum data rate of 30 kSPS. The ADS1240E/1KG4 is a 24-bit delta-sigma ADC with a 2-channel differential input multiplexer and a maximum data rate of 15 SPS. The ADS1256IDBR supports higher throughput and more input channels, while the ADS1240E/1KG4 is optimized for low-speed, high-resolution measurements.
Are the ADS1256IDBR and ADS1240E/1KG4 pin-compatible?
No. The ADS1256IDBR is supplied in a 28-pin SSOP package, while the ADS1240E/1KG4 is supplied in a 24-pin SSOP package. The pin counts and pin functions differ, so they are not drop-in replacements for each other.
What are the maximum data rates of the ADS1256IDBR and ADS1240E/1KG4?
The ADS1256IDBR supports a maximum data rate of 30 kSPS. The ADS1240E/1KG4 supports a maximum data rate of 15 SPS. The ADS1256IDBR is therefore suitable for higher-speed acquisition, while the ADS1240E/1KG4 targets low-frequency precision measurements.
How do the input channel configurations compare between the two devices?
The ADS1256IDBR provides a 4-channel differential input multiplexer, allowing up to four differential input pairs. The ADS1240E/1KG4 provides a 2-channel differential input multiplexer, allowing up to two differential input pairs. Designs requiring more differential channels should use the ADS1256IDBR.
Do both devices include a programmable gain amplifier (PGA)?
Yes. Both the ADS1256IDBR and the ADS1240E/1KG4 integrate a programmable gain amplifier. The PGA allows small sensor signals to be amplified before conversion, improving effective resolution for low-level inputs.
What are the supply voltage requirements for the ADS1256IDBR and ADS1240E/1KG4?
Both devices operate from a 5 V analog supply and a 1.8 V to 3.6 V digital supply, based on their respective manufacturer datasheets. The dual-supply arrangement allows the digital interface to match low-voltage logic while maintaining analog performance.
Which device is better suited for high-resolution, low-speed sensor measurement?
The ADS1240E/1KG4 is intended for low-speed, high-resolution measurements with a maximum data rate of 15 SPS, making it suitable for slowly varying sensor signals. The ADS1256IDBR offers higher throughput up to 30 kSPS and more input channels, so it is preferable when faster acquisition or additional differential inputs are required.
Can the ADS1256IDBR directly replace the ADS1240E/1KG4 in an existing design?
No. The devices differ in package pin count (28-pin vs 24-pin SSOP), input channel count, and maximum data rate. A direct replacement is not possible without PCB redesign and firmware changes validated against the manufacturer datasheets.