Part A
ADS1251U
德州儀器
- Lifecycle
- Active
- Stock
- 2748 件
- Package
- SOIC-8
- Series
- 資料獲取-模數轉換器（ADC）
Replacement verdict
Compatible functional replacement candidate
The ADS1251U and ADS1250UG4 are both 24-bit delta-sigma analog-to-digital converters from Texas Instruments sharing the same SOIC-8 footprint and single 5 V supply architecture, making the ADS1251U a viable functional replacement candidate for the ADS1250UG4 in many designs. However, the two devices differ in output interface, sample rate, and input configuration, so engineers must validate data rate, digital interface timing, and input signal conditioning against the target application before substituting one for the other.
Package Type
High match
Supply Voltage
High match
Output Interface
Validation required
Sample Rate
Not compatible
Parts at a glance
Part B
ADS1250UG4
德州儀器
- Lifecycle
- Active
- Stock
- 6997 件
- Package
- SOIC-16
- 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 | ADS1251U | ADS1250UG4 | Why it matters |
|---|---|---|---|
| Resolution (bits) | 24 | 20 | Higher resolution provides finer measurement granularity; a 24-bit ADC resolves much smaller signal changes than a 20-bit device, affecting precision-critical applications. |
| Number of input channels | 1 (single-ended) | 1 (differential) | Single-ended vs differential input topology changes how the sensor is wired and affects common-mode noise rejection and grounding requirements. |
| Maximum sampling rate | 20 kSPS | 25 kSPS | The sample rate determines the maximum signal bandwidth that can be captured; a faster ADC supports higher-frequency inputs and faster system throughput. |
| Interface type | SPI (serial) | SPI (serial) | Both use a serial SPI interface, but the exact protocol timing and register set differ, so firmware must be adapted when substituting one for the other. |
| Supply voltage (analog) | 5 V | 5 V | Matching analog supply voltage simplifies power-rail design, though the digital supply and internal reference architecture may still differ. |
| Internal reference | No (external reference required) | No (external reference required) | Both require an external voltage reference, so the reference circuit and its accuracy directly set the overall measurement accuracy in either design. |
| Package | SOIC-8 | SOIC-16 | Different package footprints and pin counts mean the PCB layout must be redesigned; the parts are not drop-in footprint compatible. |
| Operating temperature range | -40 °C to +85 °C | -40 °C to +85 °C | Identical temperature ratings mean both suit the same industrial environments, so thermal constraints do not differentiate the two parts. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1251U | ADS1250UG4 |
|---|---|---|
| Supplier | - | Texas Instruments |
| Part Status | Active | Obsolete |
| Number of Bits | 24 | 20 |
| Sampling Rate(Per Second) | 20k | 25k |
| Number of Inputs | 1 | 1 |
| Input Type | Differential | Differential, Single Ended |
| Data Interface | SPI | SPI |
| Configuration | ADC | PGA-ADC |
| Number of A/D Converters | 1 | 1 |
| Architecture | Sigma-Delta | Sigma-Delta |
| Reference Type | External | External |
| Voltage - Supply, Analog | 5V | 5V |
| Voltage - Supply, Digital | 5V | 5V |
| Features | - | PGA |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key differences between the ADS1251U and ADS1250UG4?
The ADS1251U is a 24-bit delta-sigma ADC with a fixed data rate of 20.8 kSPS, while the ADS1250UG4 is a 20-bit delta-sigma ADC with a programmable data rate up to 15.6 kSPS. The ADS1251U offers higher resolution, whereas the ADS1250UG4 provides a lower-resolution, lower-cost alternative with a different feature set.
Are the ADS1251U and ADS1250UG4 pin-compatible?
No. The ADS1251U is offered in an 8-pin SOIC package, while the ADS1250UG4 is offered in a 16-pin SOIC package. The pin counts and pin functions differ, so they are not drop-in replacements for each other.
What is the resolution and data rate of the ADS1251U?
The ADS1251U provides 24-bit resolution with a fixed output data rate of 20.8 kSPS. It is a single-channel delta-sigma ADC intended for high-resolution, low-speed measurement applications.
What is the resolution and data rate of the ADS1250UG4?
The ADS1250UG4 provides 20-bit resolution with a programmable output data rate up to 15.6 kSPS. It is a single-channel delta-sigma ADC suited to applications requiring moderate resolution with flexible throughput.
Do both devices support the same supply voltage range?
Both the ADS1251U and ADS1250UG4 operate from a single 5 V analog supply. Designers should confirm the exact supply and reference requirements against the respective manufacturer datasheets before finalizing a design.
Can the ADS1251U be used as a direct replacement for the ADS1250UG4?
No. The two devices differ in resolution (24-bit vs 20-bit), package (8-pin vs 16-pin SOIC), and data-rate architecture (fixed vs programmable). A direct replacement is not possible without redesigning the PCB and validating the system against the target device specifications.
Which device is better suited for high-resolution precision measurement?
The ADS1251U is better suited for high-resolution precision measurement because it offers 24-bit resolution, compared with the 20-bit resolution of the ADS1250UG4. The final choice should also account for data rate, package, and system-level requirements.