Part A
ADS1251U/2K5
德州儀器
- Lifecycle
- Active
- Stock
- 4208 件
- Package
- SOIC-8
- Series
- 資料獲取-模數轉換器（ADC）
Replacement verdict
Not a drop-in replacement
The ADS1251U/2K5 and ADS1250UG4 are both 24-bit delta-sigma ADCs, but they differ in resolution architecture, input configuration, package footprint, and interface timing, so the ADS1250UG4 cannot serve as a direct drop-in substitute for the ADS1251U/2K5 without design validation.
Different input configuration
Different package footprint
Different interface timing
Different reference architecture
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/2K5 | 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 ADC, affecting precision-critical designs. |
| Sample Rate (max) | 20 kSPS | 25 kSPS | Maximum sampling rate determines the highest signal bandwidth that can be digitized; the ADS1250 supports slightly faster sampling. |
| Number of Input Channels | 1 (differential) | 1 (differential) | Both are single-channel differential devices, so channel count is functionally equivalent for single-sensor applications. |
| Input Type | Differential | Differential | Differential inputs reject common-mode noise, which is important for low-level sensor measurements; both parts share this characteristic. |
| Interface | SPI (serial) | SPI (serial) | A compatible serial interface simplifies drop-in replacement and microcontroller connection; both use SPI. |
| Supply Voltage (analog) | 5 V | 5 V | Matching analog supply requirements allows reuse of the same power rail and reference design. |
| Package / Mounting | 8-SOIC (surface mount) | 16-SOIC (surface mount) | Different package footprints and pin counts mean the PCB layout must be redesigned; they are not pin-compatible drop-in replacements. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Identical temperature ratings ensure equivalent environmental robustness for industrial applications. |
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 | ADS1251U/2K5 | 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/2K5 and the ADS1250UG4?
The ADS1251U/2K5 is a 24-bit delta-sigma ADC with a fixed data rate of 20 kSPS, while the ADS1250UG4 is a 20-bit delta-sigma ADC with a programmable data rate up to 15 kSPS. The ADS1251U/2K5 offers higher resolution, whereas the ADS1250UG4 provides a different resolution and speed trade-off. Both are single-channel devices, but they differ in resolution, output data rate, and package options.
Are the ADS1251U/2K5 and ADS1250UG4 pin-compatible?
No, they are not pin-compatible. The ADS1251U/2K5 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 cannot be directly interchanged on the same PCB footprint.
What is the resolution and data rate of each device?
The ADS1251U/2K5 provides 24-bit resolution with a fixed 20 kSPS output data rate. The ADS1250UG4 provides 20-bit resolution with a programmable output data rate up to 15 kSPS. The ADS1251U/2K5 is suited for higher-resolution, fixed-rate applications, while the ADS1250UG4 offers flexibility in data rate at a lower resolution.
Do both devices use the same digital interface?
No. The ADS1251U/2K5 uses a synchronous serial interface compatible with SPI, while the ADS1250UG4 uses a two-wire serial interface. The interface protocols and timing differ, so firmware and host controller connections must be adapted accordingly.
Can the ADS1251U/2K5 be used as a drop-in replacement for the ADS1250UG4?
No. The two devices differ in package, pin count, resolution, data rate, and digital interface. A direct drop-in replacement is not possible; any substitution requires a redesign of the PCB footprint, interface firmware, and validation of system performance against the target specifications.
What are the typical applications for each device?
The ADS1251U/2K5 is typically used in high-resolution measurement systems such as industrial process control, weigh scales, and precision sensor interfaces where 24-bit resolution at 20 kSPS is required. The ADS1250UG4 is used in applications requiring 20-bit resolution with a programmable data rate, such as portable instrumentation and data acquisition systems where flexibility in speed and power is important.
Do both devices operate from the same supply voltage?
Both devices operate from a single 5 V analog supply. However, designers should consult the respective manufacturer datasheets to confirm supply voltage ranges, reference requirements, and power consumption, as these parameters may differ between the two devices.