Part A
ADS1256IDBR
德州儀器
- Lifecycle
- Active
- Stock
- 4327 件
- Package
- SSOP-28
- Series
- 資料獲取-模數轉換器（ADC）
Replacement verdict
Not a drop-in replacement
The ADS1256IDBR and ADS1240EG4 are not drop-in replacements for one another. Although both are 24-bit delta-sigma ADCs from Texas Instruments, they differ in resolution architecture, channel count, package footprint, and interface configuration, so a direct board-level substitution is not feasible without redesign.
Different channel count
Different package footprint
Different data interface
Different input configuration
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 | ADS1256IDBR | ADS1240EG4 | Why it matters |
|---|---|---|---|
| Resolution (bits) | 24 | 24 | Both are 24-bit delta-sigma ADCs, so resolution alone does not differentiate them for high-precision measurement applications. |
| Number of input channels | 8 (single-ended) / 4 (differential) | 4 (single-ended) / 2 (differential) | Channel count determines how many sensors or signals can be multiplexed into one ADC, directly affecting system architecture and board space. |
| Maximum sample rate (SPS) | 30k | 15 | Sample rate sets the maximum signal bandwidth and throughput; the ADS1256 supports much faster data acquisition than the ADS1240. |
| Programmable gain amplifier (PGA) range | 1 to 64 | 1 to 128 | PGA gain range determines the smallest input signal that can be resolved; the ADS1240 offers higher gain for very low-level signals. |
| Supply voltage (analog) | 5 V (single supply) | 2.7 V to 5.25 V | Supply voltage compatibility affects whether the part can drop into a given power rail design without additional regulation. |
| Interface | SPI | SPI | Both use a serial SPI interface, so the digital host connection is functionally compatible between the two parts. |
| Package | SSOP-28 | SSOP-28 | Package footprint and pin count affect PCB layout compatibility and whether a direct board substitution is possible. |
| Operating temperature range | -40°C to +85°C | -40°C to +85°C | Temperature range determines suitability for industrial and harsh-environment applications; both parts share the same industrial range. |
| Input type | Differential / single-ended | Differential / single-ended | Input configuration flexibility affects how sensors can be connected and whether common-mode noise can be rejected effectively. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1256IDBR | ADS1240EG4 |
|---|---|---|
| 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 primary differences between the ADS1256IDBR and the ADS1240EG4?
The ADS1256IDBR is a 24-bit, 8-channel delta-sigma ADC with a maximum data rate of 30 kSPS, housed in a 28-pin SSOP package. The ADS1240EG4 is a 24-bit, 4-channel delta-sigma ADC with a maximum data rate of 15 kSPS, housed in a 24-pin SSOP package. The ADS1256IDBR provides twice the input channel count and twice the maximum data rate of the ADS1240EG4.
Are the ADS1256IDBR and ADS1240EG4 pin-compatible?
No. The ADS1256IDBR uses a 28-pin SSOP package, while the ADS1240EG4 uses a 24-pin SSOP package. The differing pin counts and pin functions prevent direct PCB footprint compatibility without a layout redesign.
What are the maximum data rates of the ADS1256IDBR and ADS1240EG4?
The ADS1256IDBR supports a maximum programmable data rate of 30 kSPS. The ADS1240EG4 supports a maximum data rate of 15 kSPS. Both devices use a programmable gain amplifier and delta-sigma architecture, but the ADS1256IDBR offers higher throughput.
How many input channels does each device provide?
The ADS1256IDBR provides 8 single-ended or 4 differential input channels. The ADS1240EG4 provides 4 single-ended or 2 differential input channels. Designs requiring more than four single-ended inputs must use the ADS1256IDBR or an external multiplexer.
Do both devices support the same supply voltage range?
Both the ADS1256IDBR and ADS1240EG4 operate from a single analog supply of 5 V and a digital supply of 1.8 V to 3.6 V, per their respective manufacturer datasheets. The ADS1256IDBR additionally specifies an analog supply range of 4.75 V to 5.25 V. Designers should verify the exact supply limits in the official datasheets before finalizing power architecture.
Can the ADS1240EG4 be used as a drop-in replacement for the ADS1256IDBR?
No. The ADS1240EG4 is not a drop-in replacement for the ADS1256IDBR due to differences in package pin count (24 vs 28 pins), channel count (4 vs 8 channels), and maximum data rate (15 kSPS vs 30 kSPS). A replacement requires PCB redesign and firmware adjustment for the different register map and channel configuration.
What communication interface do the ADS1256IDBR and ADS1240EG4 use?
Both devices use a serial peripheral interface (SPI) for communication with a host microcontroller. The ADS1256IDBR supports SPI-compatible serial interface with a maximum SCLK frequency specified in its datasheet, and the ADS1240EG4 also uses an SPI-compatible interface. Firmware must account for differences in register maps and command sets between the two devices.
Which device is better suited for multi-channel sensor acquisition?
The ADS1256IDBR is better suited for multi-channel sensor acquisition because it provides 8 single-ended or 4 differential inputs, compared with 4 single-ended or 2 differential inputs on the ADS1240EG4. For systems requiring more than four single-ended sensor channels, the ADS1256IDBR avoids the need for an external multiplexer.