Part A
ADS1251U/2K5
텍사스 인스트루먼트(주)
- Lifecycle
- Active
- Stock
- 4208 PCS
- Package
- SOIC-8
- Series
- 데이터 수집 - 아날로그 변환기(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
Parts at a glance
Part B
ADS1286UL
텍사스 인스트루먼트(주)
- Lifecycle
- Active
- Stock
- 9742 PCS
- Package
- SOIC-8
- Series
- 데이터 수집 - 아날로그 변환기(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 | 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.