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 ADS1286UL are both 24-bit delta-sigma ADCs, but they differ fundamentally in resolution architecture, input configuration, package footprint, and digital interface, so the ADS1286UL cannot serve as a direct drop-in substitute for the ADS1251U/2K5 without a full board and firmware redesign.
Different input configuration
Different package footprint
Different digital interface
Different reference architecture
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 | ADS1286UL | Why it matters |
|---|---|---|---|
| Resolution (bits) | 24 | 12 | Resolution determines the smallest signal change the ADC can distinguish; a 24-bit device offers far finer measurement granularity than a 12-bit device. |
| Architecture | Delta-Sigma | SAR | Delta-sigma ADCs excel at high-resolution low-frequency signals, while SAR ADCs offer faster conversions and lower latency; architecture drives the application fit. |
| Sample Rate (max) | 20 kSPS | 20 kSPS | Maximum throughput defines how fast the system can acquire samples; both parts share the same nominal rate despite different architectures. |
| Input Type | Differential | Differential | Differential inputs reject common-mode noise and improve accuracy in noisy environments; both devices support differential measurement. |
| Supply Voltage | 5 V (single) | 5 V (single) | Supply voltage must match the system rail; both parts operate from a single 5 V supply, simplifying power design. |
| Interface | Serial (SPI-compatible) | Serial (SPI-compatible) | A compatible serial interface allows connection to common microcontrollers without protocol changes. |
| Package | SOIC-8 | SOIC-8 | Package footprint affects PCB layout and assembly; matching packages ease board-level substitution. |
| Operating Temperature Range | -40 to +85 °C | -40 to +85 °C | Temperature range determines suitability for industrial and outdoor environments; both cover the standard industrial range. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1251U/2K5 | ADS1286UL |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC,Texas Instruments |
| Part Status | Active | Obsolete |
| Number of Bits | 24 | 12 |
| Sampling Rate(Per Second) | 20k | 20k |
| Number of Inputs | 1 | 1 |
| Input Type | Differential | Differential |
| Data Interface | SPI | SPI |
| Configuration | ADC | S/H-ADC |
| Ratio - S / H: ADC | - | 1:1 |
| Number of A/D Converters | 1 | 1 |
| Architecture | Sigma-Delta | SAR |
| Reference Type | External | External |
| Voltage - Supply, Analog | 5V | 5V |
| Voltage - Supply, Digital | 5V | 5V |
| Operating Temperature | -40°C ~ 85°C | 0°C ~ 70°C |
Frequently asked questions
What are the key architectural differences between the ADS1251U/2K5 and the ADS1286UL?
The ADS1251U/2K5 is a 24-bit delta-sigma analog-to-digital converter with a single differential input and a fixed data rate of 20 kSPS, housed in an SOIC-8 package. The ADS1286UL is a 12-bit successive-approximation register (SAR) ADC with a single-ended input, a maximum sampling rate of 20 kSPS, and is offered in an MSOP-8 package. They differ fundamentally in resolution architecture (delta-sigma vs. SAR) and input configuration (differential vs. single-ended).
Are the ADS1251U/2K5 and ADS1286UL pin-compatible or footprint-compatible?
No. The ADS1251U/2K5 uses an SOIC-8 package, while the ADS1286UL uses an MSOP-8 package. These are different package outlines with different body dimensions and lead pitches, so they are not drop-in replacements and require different PCB land patterns.
How do the resolutions and effective performance of these two ADCs compare?
The ADS1251U/2K5 provides 24-bit resolution using a delta-sigma modulator, making it suited to low-frequency, high-precision measurements. The ADS1286UL provides 12-bit resolution using a SAR architecture, targeting faster, lower-resolution signal acquisition. The resolution difference is a factor of 4096 in code count, so the two parts serve fundamentally different precision requirements.
Do the ADS1251U/2K5 and ADS1286UL support the same input signal configuration?
No. The ADS1251U/2K5 has a differential input, which helps reject common-mode noise and is beneficial for low-level sensor signals. The ADS1286UL has a single-ended input referenced to ground. Designs requiring differential signal conditioning cannot use the ADS1286UL without additional circuitry.
What are the maximum sampling rates of the ADS1251U/2K5 and ADS1286UL?
The ADS1251U/2K5 operates at a fixed 20 kSPS output data rate. The ADS1286UL supports sampling rates up to 20 kSPS. Although the maximum rates are similar, the ADS1251U/2K5 rate is fixed by its delta-sigma modulator and digital filter, whereas the ADS1286UL rate is set by the external conversion timing.
Can the ADS1286UL directly replace the ADS1251U/2K5 in an existing 24-bit design?
No. Replacing a 24-bit delta-sigma converter with a 12-bit SAR converter would reduce resolution by 12 bits, change the input from differential to single-ended, and require a different package footprint. Such a substitution would not preserve the original measurement performance or board layout.
Which applications are better suited to each converter?
The ADS1251U/2K5 is appropriate for high-resolution, low-frequency measurements such as precision sensor interfaces, weigh scales, and industrial process control where 24-bit delta-sigma performance is needed. The ADS1286UL is appropriate for lower-resolution, general-purpose data acquisition where a 12-bit SAR converter with a small MSOP-8 footprint is sufficient.