Part A
ADS1251U
德州儀器
- Lifecycle
- Active
- Stock
- 2748 件
- Package
- SOIC-8
- Series
- 資料獲取-模數轉換器（ADC）
Replacement verdict
Not a drop-in replacement
The ADS1251U and ADS1201U/1K are both 24-bit delta-sigma analog-to-digital converters, but they are not functionally interchangeable: the ADS1251U is a single-channel, high-resolution ADC with a fixed 20SPS data rate and SPI-compatible serial interface, while the ADS1201U/1K is a single-channel delta-sigma modulator with a 10MHz master clock and a 1-bit modulator output requiring external digital filtering. The differing output architecture, data rate, clocking scheme, and package options mean the ADS1201U/1K cannot directly replace the ADS1251U in an existing design without significant rework.
Different output architecture
Different data rate
Different clocking scheme
Different package options
Parts at a glance
Part B
ADS1201U/1K
德州儀器
- Lifecycle
- Active
- Stock
- 9427 件
- Package
- SOIC-16
- Series
- 資料獲取-ADC DAC-專用
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 | ADS1201U/1K | Why it matters |
|---|---|---|---|
| Resolution (bits) | 24 | 24 | Both are 24-bit delta-sigma converters, so nominal resolution is equivalent for high-precision measurement applications. |
| Architecture | Delta-Sigma (low-speed, high-resolution ADC) | Delta-Sigma modulator (single-bit output) | The ADS1251U is a complete ADC with digital filter and serial output, while the ADS1201U is a modulator requiring external digital filtering, so they are not drop-in substitutes. |
| Output Interface | Serial (SPI-compatible, 24-bit words) | Single-bit modulator bitstream | The output format determines whether a host can read the device directly or must implement a sinc/decimation filter, affecting system architecture. |
| Data Rate / Output Word Rate | Up to ~20 kSPS (programmable) | Modulator clock dependent (up to ~10 MHz clock) | Achievable sample rate and filtering trade-offs differ, influencing bandwidth and noise performance in the target design. |
| Input Type | Differential | Differential | Both accept differential inputs, which is important for rejecting common-mode noise in precision sensing. |
| Supply Voltage | +5 V analog supply (with digital supply) | +5 V analog supply (with digital supply) | Supply compatibility affects whether the part can be used in the same power rail configuration without redesign. |
| Package | SOIC-8 | SOIC-16 | Different package pin counts and footprints prevent direct board-level substitution without layout changes. |
| Internal Digital Filter | Yes (on-chip sinc filter, decimation) | No (external digital filter required) | The presence of an internal filter simplifies system design and reduces external component count, a key functional difference. |
| Typical Application | Precision measurement, industrial sensors, weigh scales | Motor control, power measurement, isolated sensing with external filtering | Intended use cases indicate whether the device fits the target signal chain and isolation/filtering requirements. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS1251U | ADS1201U/1K |
|---|---|---|
| Supplier | - | Texas Instruments,Rochester Electronics, LLC |
| Part Status | Active | Active |
| 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 differences between the ADS1251U and the ADS1201U/1K?
The ADS1251U is a 24-bit delta-sigma analog-to-digital converter with a fixed data rate of 20 kSPS, while the ADS1201U/1K is a 24-bit delta-sigma modulator with a 10 MHz master clock and a programmable decimation ratio, typically used with an external digital filter. The ADS1251U integrates a digital filter and provides a complete ADC solution, whereas the ADS1201U/1K outputs a 1-bit modulator stream requiring external filtering.
Are the ADS1251U and ADS1201U/1K pin-compatible?
No. The ADS1251U is offered in an 8-pin SOIC package, while the ADS1201U/1K is offered in a 16-pin SOIC package. The pin functions and package dimensions differ, so they are not drop-in replacements for each other.
What are the resolution and data rate specifications for each device?
The ADS1251U provides 24-bit resolution with a fixed 20 kSPS output data rate. The ADS1201U/1K is a 24-bit delta-sigma modulator that outputs a 1-bit stream at a rate determined by the master clock (up to 10 MHz) and the decimation ratio; the effective resolution depends on the external digital filter and decimation settings.
Can the ADS1201U/1K be used as a direct replacement for the ADS1251U in an existing design?
No. The ADS1251U includes an on-chip digital filter and provides a complete serial output at 20 kSPS, while the ADS1201U/1K requires an external digital filter to convert the 1-bit modulator output into a usable data word. Replacing one with the other requires redesign of the digital interface and filtering, and the packages are not compatible.
What are the typical applications for each device?
The ADS1251U is suited for precision measurement systems requiring a complete 24-bit ADC with a fixed 20 kSPS rate, such as industrial process control and instrumentation. The ADS1201U/1K is intended for applications where the modulator output is processed by an external digital filter, such as motor control, power measurement, and isolated signal chains.
Do both devices operate from the same supply voltage?
The ADS1251U operates from a single 5 V analog supply (with a separate digital supply). The ADS1201U/1K operates from a 5 V analog supply and a 3 V to 5 V digital supply. Designers should verify the exact supply requirements in the respective manufacturer datasheets before substitution.
What is the difference in output interface between the ADS1251U and ADS1201U/1K?
The ADS1251U provides a serial SPI-compatible output with 24-bit converted data words at 20 kSPS. The ADS1201U/1K provides a 1-bit delta-sigma modulator output stream that must be processed by an external digital filter (e.g., a sinc filter) to obtain a multi-bit result.