Part A
ADC121S051CIMF
Texas Instruments
- Lifecycle
- Active
- Stock
- 1513 PCS
- Package
- SOT-23-6
- Series
- Acquisition de données - Convertisseur analogique - numérique (ADC)
Replacement verdict
Compatible functional replacement candidate
The ADC121S021CIMFX is a functional replacement candidate for the ADC121S051CIMF, sharing the same 12-bit SAR architecture, SPI interface, SOT-23-6 package, and supply voltage range. The primary distinction is resolution-related throughput and dynamic performance, so the substitution is viable for applications where the lower sampling rate and reduced SNR of the ADC121S021 are acceptable. Designers should validate timing margins and signal-to-noise requirements against the target application before committing to the swap.
Resolution and Architecture
High match
Sampling Rate
Validation required
Package Type
High match
Dynamic Performance
Validation required
Parts at a glance
Part B
ADC121S021CIMFX
Texas Instruments
- Lifecycle
- Active
- Stock
- 7767 PCS
- Package
- SOT-23-6
- 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 | ADC121S051CIMF | ADC121S021CIMFX | Why it matters |
|---|---|---|---|
| Resolution | 12 bit | 12 bit | Both converters provide 12-bit resolution, so quantization step size is identical and no resolution-related redesign is needed. |
| Sampling Rate | 500 kSPS | 200 kSPS | The maximum throughput differs; the 500 kSPS device can digitize faster signals, while the 200 kSPS part limits the maximum input bandwidth and update rate. |
| Number of Input Channels | 1 single-ended | 1 single-ended | Both are single-channel devices, so the same analog signal path and channel count can be reused. |
| Interface Type | SPI / QSPI / MICROWIRE compatible serial | SPI / QSPI / MICROWIRE compatible serial | Identical serial interface means the same microcontroller pins and firmware protocol can drive either part. |
| Supply Voltage Range | 2.7 V to 5.25 V | 2.7 V to 5.25 V | Matching supply ranges allow the same power rail to be used without level shifting or regulator changes. |
| Package | SOT-23-6 | SOT-23-6 | Same package and pinout enable a drop-in board replacement without layout changes. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Equivalent temperature ratings ensure both parts suit the same industrial and commercial environments. |
| Power Consumption (Typical at 3 V) | Approximately 2.5 mW at 500 kSPS | Approximately 1.0 mW at 200 kSPS | Lower sampling rate reduces power draw; the 200 kSPS part is preferable for power-sensitive designs, while the 500 kSPS part trades power for speed. |
| Conversion Time | Shorter (supports 500 kSPS throughput) | Longer (supports 200 kSPS throughput) | Conversion time directly bounds achievable sample rate and latency in control loops; the faster part reduces acquisition latency. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADC121S051CIMF | ADC121S021CIMFX |
|---|---|---|
| Supplier | - | Texas Instruments |
| Part Status | Obsolete | Obsolete |
| Number of Bits | 12 | 12 |
| Sampling Rate(Per Second) | 500k | 200k |
| Number of Inputs | 1 | 1 |
| Input Type | Single Ended | Single Ended |
| Data Interface | SPI, DSP | SPI, DSP |
| Configuration | S/H-ADC | S/H-ADC |
| Ratio - S / H: ADC | 1:1 | 1:1 |
| Number of A/D Converters | 1 | 1 |
| Architecture | SAR | SAR |
| Reference Type | Supply | Supply |
| Voltage - Supply, Analog | 2.7V ~ 5.25V | 2.7V ~ 5.25V |
| Voltage - Supply, Digital | 2.7V ~ 5.25V | 2.7V ~ 5.25V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key differences between the ADC121S051CIMF and the ADC121S021CIMFX?
The primary difference is resolution and sample rate. The ADC121S051CIMF is a 12-bit, 500 kSPS to 1 MSPS analog-to-digital converter, while the ADC121S021CIMFX is a 12-bit, 50 kSPS to 200 kSPS ADC. Both are single-channel, micropower, successive-approximation ADCs from Texas Instruments in a 6-pin SOT-23 package, but they target different throughput requirements.
Are the ADC121S051CIMF and ADC121S021CIMFX pin-compatible?
Yes. Both devices are offered in the same 6-pin SOT-23 (DBV) package with the same pinout: VIN, GND, VA, CS, SCLK, and DOUT. This allows a common PCB footprint, but the different maximum sample rates must be considered when evaluating a substitution.
What is the maximum sampling rate of each device?
The ADC121S051CIMF supports a maximum throughput of 1 MSPS (with a minimum of 500 kSPS specified), while the ADC121S021CIMFX supports a maximum throughput of 200 kSPS (with a minimum of 50 kSPS specified). The system clock and CS timing must be designed accordingly.
Do both converters use the same serial interface?
Yes. Both use a SPI-compatible serial interface with CS, SCLK, and DOUT signals, allowing direct connection to standard microcontrollers and DSPs. The interface timing scales with the respective maximum SCLK frequency of each device.
What is the supply voltage range for these ADCs?
Both the ADC121S051CIMF and ADC121S021CIMFX operate from a single analog supply (VA) of 2.7 V to 5.25 V, making them suitable for 3 V and 5 V systems. The digital interface levels are referenced to the same supply.
How do the power consumption figures compare?
Both devices are micropower SAR converters with power consumption that scales with throughput. Because the ADC121S021CIMFX operates at a lower maximum sample rate, its typical power consumption at its rated throughput is lower than that of the ADC121S051CIMF running at its higher throughput. Exact values should be taken from the respective TI datasheets.
Can the ADC121S021CIMFX be used as a drop-in replacement for the ADC121S051CIMF?
Only if the system's required sample rate is 200 kSPS or less and the timing, accuracy, and power budgets are revalidated. The pinout and package are identical, but the lower maximum throughput of the ADC121S021CIMFX means it cannot meet applications requiring the higher conversion rate of the ADC121S051CIMF.