Part A
ADS1251U/2K5
Texas Dụng cụ
- Lifecycle
- Active
- Stock
- 4208 PCS
- Package
- SOIC-8
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Not a drop-in replacement
The ADS1251U/2K5 and ADS1201UG4 are not drop-in replacements for each other. Although both are 24-bit delta-sigma analog-to-digital converters, they differ in resolution architecture, output interface, package footprint, and reference/supply configuration, so a direct board-level substitution is not possible without redesign.
Different output interface
Different package footprint
Different input architecture
Different supply configuration
Parts at a glance
Part B
ADS1201UG4
Texas Dụng cụ
- Lifecycle
- Active
- Stock
- 6830 PCS
- Package
- SOIC-16
- Series
- Data Acquisition - ADCs-DACs - Special Purpose
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 | ADS1201UG4 | Why it matters |
|---|---|---|---|
| Resolution (bits) | 24 | 24 | Both are 24-bit delta-sigma converters, so resolution alone does not distinguish them for substitutability. |
| Architecture | Delta-Sigma ADC (voltage input) | Delta-Sigma Modulator (1-bit output) | The ADS1251 is a complete ADC with digital output; the ADS1201 is a modulator requiring external digital filtering, so they are not drop-in substitutes. |
| Output Interface | Serial (SPI-compatible) | 1-bit serial bitstream | Different output formats require different downstream processing, affecting system-level interchangeability. |
| Input Type | Differential voltage | Differential voltage | Both accept differential voltage inputs, which is relevant for sensor signal conditioning compatibility. |
| Data Rate / Sample Rate | Up to ~20 kSPS | Up to ~40 kSPS (modulator clock dependent) | Sample rate determines achievable bandwidth and affects suitability for higher-speed measurement applications. |
| Supply Voltage | 5 V analog supply | 5 V analog supply | Matching supply requirements simplifies power-rail design when considering substitution. |
| Package | SOIC-8 | SOIC-16 | Different package footprints and pin counts prevent direct board-level replacement without layout changes. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +85°C | Identical temperature ratings mean both suit the same industrial environmental conditions. |
| Internal PGA / Gain | No internal PGA | No internal PGA | Neither integrates programmable gain, so external amplification is needed for small signals in both cases. |
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Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1251U/2K5 | ADS1201UG4 |
|---|---|---|
| Supplier | - | Texas Instruments |
| Part Status | Active | Discontinued at Digi-Key |
| Type | - | Modulator |
| Number of Channels | - | 1 |
| Resolution(Bits) | - | 24 b |
| Sampling Rate(Per Second) | 20k | 1k |
| Data Interface | SPI | Serial |
| Voltage Supply Source | - | Analog and Digital |
| Voltage - Supply | - | 4.75V ~ 5.25V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | - | Surface Mount |
| Number of Bits | 24 | - |
| Number of Inputs | 1 | - |
| Input Type | Differential | - |
| Configuration | ADC | - |
| Number of A/D Converters | 1 | - |
| Architecture | Sigma-Delta | - |
| Reference Type | External | - |
| Voltage - Supply, Analog | 5V | - |
| Voltage - Supply, Digital | 5V | - |
Frequently asked questions
What are the primary functional differences between the ADS1251U/2K5 and the ADS1201UG4?
The ADS1251U/2K5 is a 24-bit delta-sigma analog-to-digital converter with a fixed data rate of 20 kSPS, designed for high-resolution DC and low-frequency measurement. The ADS1201UG4 is a 24-bit delta-sigma modulator that outputs a 1-bit serial bitstream at a 10 MHz clock, intended for isolated signal conditioning and applications requiring digital filtering in an external FPGA or DSP. The ADS1251 integrates the digital filter and provides a complete ADC solution, while the ADS1201 provides only the modulator stage.
Are the ADS1251U/2K5 and ADS1201UG4 pin-compatible or package-compatible?
No. The ADS1251U/2K5 is supplied in an 8-pin SOIC package (U suffix), while the ADS1201UG4 is supplied in a 16-pin SOIC package (UG4 suffix). The pin counts, pin functions, and PCB land patterns differ, so these devices are not drop-in replacements for one another.
What are the resolution and output data rate specifications for each device?
The ADS1251U/2K5 provides 24-bit resolution with a fixed 20 kSPS output data rate and an integrated digital filter. The ADS1201UG4 provides 24-bit modulator resolution with a 1-bit serial output stream; its effective output word rate depends on the external digital filter and the applied modulator clock (up to 10 MHz), not on an internally fixed data rate.
Which device is better suited for isolated measurement applications?
The ADS1201UG4 is specifically intended for isolated signal conditioning because its 1-bit modulator output can be passed through a single digital isolator, with filtering performed on the isolated or non-isolated side by an FPGA or DSP. The ADS1251U/2K5 provides a parallel or serial word output from an integrated ADC and is not optimized for single-channel digital isolation architectures.
Do both devices support the same supply voltage and reference requirements?
Both devices operate from a single 5 V analog supply and support an external reference voltage. However, the ADS1251U/2K5 integrates the digital filter and clock generation circuitry, while the ADS1201UG4 requires an external modulator clock (up to 10 MHz) and external digital filtering. Designers must verify reference drive requirements and clock source availability against the respective datasheets.
Can the ADS1201UG4 replace the ADS1251U/2K5 in an existing design without firmware changes?
No. The ADS1251U/2K5 outputs a filtered digital word at 20 kSPS, whereas the ADS1201UG4 outputs an unfiltered 1-bit bitstream that requires an external digital filter (typically in an FPGA or DSP) to produce a usable conversion result. Replacing one with the other requires changes to the digital interface, clocking, and signal processing chain.
What are the typical target applications for each device?
The ADS1251U/2K5 is typically used in high-resolution industrial measurement, weigh scales, and low-frequency data acquisition where an integrated ADC with a fixed 20 kSPS rate is sufficient. The ADS1201UG4 is typically used in isolated current and voltage sensing, motor control feedback, and power measurement systems where the modulator output is digitally isolated and filtered externally.