Part A
ADS1251U/2K5
Texas Instruments
- Lifecycle
- Active
- Stock
- 4208 PCS
- Package
- SOIC-8
- Series
- Acquisition de données - Convertisseur analogique - numérique (ADC)
Replacement verdict
Compatible functional replacement candidate
The ADS1251U/2K5 and ADS1251UG4 are functionally equivalent, sharing the same 24-bit delta-sigma ADC core, SPI interface, SOIC-8 package, and specified operating temperature range. The only distinction is the ordering suffix and packaging format, so the ADS1251UG4 can serve as a direct functional substitute for the ADS1251U/2K5 in existing designs without electrical or layout changes.
Resolution and ADC Architecture
High match
Package Type
High match
Digital Interface
High match
Operating Temperature Range
High match
Parts at a glance
Part B
ADS1251UG4
Texas Instruments
- Lifecycle
- Active
- Stock
- 2511 PCS
- Package
- SOIC-8
- Series
- Acquisition de données - Convertisseur analogique - numérique (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 | ADS1251UG4 | Why it matters |
|---|---|---|---|
| Resolution | 24 bit | 24 bit | Determines the smallest signal change the ADC can resolve; identical resolution means equivalent measurement precision. |
| Number of Input Channels | 1 (differential) | 1 (differential) | Defines how many signal sources can be measured; both are single-channel differential devices, so they are interchangeable in single-sensor designs. |
| Sampling Rate | 20 kSPS | 20 kSPS | Sets the maximum data throughput; matching rates ensure identical timing behavior in the application. |
| Interface Type | SPI (serial) | SPI (serial) | Determines compatibility with the host microcontroller; identical serial interface allows drop-in replacement. |
| Supply Voltage | 5 V (analog and digital) | 5 V (analog and digital) | Must match the system power rail; identical supply requirements mean no power redesign is needed. |
| Package / Mounting | 8-SOIC, surface mount | 8-SOIC, surface mount | Affects PCB footprint and assembly; identical package and mounting allow the same board layout. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Defines the environmental limits of reliable operation; matching ranges ensure equivalent robustness. |
| Packaging / Ordering Quantity | Tape and reel (2000 units) | Tube / bulk | Affects manufacturing handling and inventory; the reel version suits automated assembly while the tube version suits prototyping or low-volume runs. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1251U/2K5 | ADS1251UG4 |
|---|---|---|
| Supplier | - | Texas Instruments |
| Part Status | Active | Discontinued at Digi-Key |
| Number of Bits | 24 | 24 |
| Sampling Rate(Per Second) | 20k | 20k |
| Number of Inputs | 1 | 1 |
| Input Type | Differential | Differential |
| Data Interface | SPI | SPI |
| Configuration | ADC | 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 |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key differences between the ADS1251U/2K5 and the ADS1251UG4?
Both parts are the same ADS1251 24-bit delta-sigma analog-to-digital converter from Texas Instruments in an SOIC-8 (D) package. The difference is ordering and packaging: ADS1251U/2K5 is supplied in tape-and-reel format (2,000 units per reel), while ADS1251UG4 uses the "G4" suffix, which denotes lead-free (RoHS-compliant) construction in tube/rail packaging. The electrical specifications and functional performance of the two devices are identical.
Are the ADS1251U/2K5 and ADS1251UG4 electrically and functionally interchangeable?
Yes. Both devices share the same die, pinout, and datasheet specifications for the ADS1251 (24-bit resolution, differential input, 20kHz data rate, 5V analog supply, SPI-compatible serial interface). They differ only in packaging format and the G4 lead-free designation, so they are functionally interchangeable in a given design.
What does the "G4" suffix on the ADS1251UG4 indicate?
The G4 suffix is Texas Instruments' designation for lead-free (Pb-free), RoHS-compliant package construction. The ADS1251UG4 is therefore the lead-free version of the ADS1251 in the SOIC-8 package, suitable for designs requiring RoHS compliance.
What does the "/2K5" suffix on the ADS1251U/2K5 mean?
The /2K5 suffix indicates tape-and-reel packaging with 2,000 devices per reel, intended for automated high-volume SMT assembly. It does not change the device's electrical characteristics compared with other ADS1251 orderable variants.
Do the ADS1251U/2K5 and ADS1251UG4 have the same package and pinout?
Yes. Both are offered in the SOIC-8 (D) package with the same pin assignment, so PCB land patterns and footprint are identical. The only distinction is the reel-versus-tube packaging and the G4 lead-free marking.
Which part should be selected for high-volume automated assembly?
The ADS1251U/2K5 is the appropriate choice for high-volume automated SMT lines because it is supplied in tape-and-reel (2,000 units per reel). The ADS1251UG4, supplied in tubes, is typically used for prototyping, low-volume runs, or where RoHS-compliant lead-free construction is specifically required.
Are both variants RoHS compliant?
The ADS1251UG4 is explicitly designated with the G4 lead-free/RoHS-compliant suffix. For the ADS1251U/2K5, RoHS status should be confirmed against the specific orderable part number and the manufacturer's current product page or datasheet, since the /2K5 suffix denotes packaging rather than the lead-free designation.