ADC1251CIJ - 12-Bit+Sign Self-Calibrating SAR ADC | Texas Instruments
N.º de pieza: ADC1251CIJ ✗ Fin de vida| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $18.5 | $18,50 |
| 10 | $16.2 | $162,00 |
| 100 | $14.05 | $1.405,00 |
| 500 | $12.4 | $6.200,00 |
| 1.000 | $10.95 | $10.950,00 |
ADC1251CIJ Descripción general
An SAR ADC (Successive Approximation Register Analog-to-Digital Converter) is a converter architecture that resolves each input sample in N successive bit-trial cycles, using an internal DAC, comparator, and digital register. SAR ADCs are valued in data-acquisition systems for their deterministic latency, single-shot accuracy without pipeline delay, and predictable behavior on multiplexed or burst-mode inputs. The ADC1251 sits in the precision industrial-measurement segment of the data-converter hierarchy: SAR -> ADC -> data converter -> signal-chain IC -> semiconductor.
Key features of the ADC1251CIJ include 12-bit plus sign resolution, 83 kSPS maximum sampling rate, on-chip sample-and-hold amplifier, self-calibration on demand, parallel-word digital output, and CMOS low-power design. Operating from -40C to +85C industrial temperature range, the part accepts bipolar analog input ranges when properly referenced and is suitable for environments that require stable, repeatable conversion accuracy over time without external trimming.
The internal architecture pairs a capacitive-charge-distribution DAC with an on-chip comparator and a self-calibration state machine. The calibration cycle stores correction coefficients that are applied on every conversion, reducing offset drift and scale error to levels that would otherwise require periodic manual trimming. The parallel-word output connects directly to microprocessors, DSPs, or external latches, simplifying interface hardware.
Typical applications include industrial process control loops, precision weigh-scale and load-cell digitizers, data-logging front-ends, multichannel instrumentation panels, and medical monitoring front-ends. The ceramic DIP package supports through-hole assembly preferred in legacy, high-reliability, and military-temperature systems.
When designing with the ADC1251CIJ, take care to bypass the analog supply pins close to the package with both bulk and ceramic capacitors, keep analog and digital ground returns separated until they meet at one star point, and issue a calibration command after power-up and after any large temperature change to maintain specified accuracy.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
Alternativas directas para ADC1251CIJ — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
ADC1251CIJ
✅ Sustitución directa✓ En stock
$10.95 / unidad
Ver hoja de datos →AD574AJN
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
AD677AJN
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
ADC1251CIJ Valores máximos y características eléctricas
| Resolución | 12 bit + sign |
| Architecture | SAR (Successive Approximation) |
| Number of Input Channels | 1 |
| Frecuencia de muestreo | 83 kSPS |
| Input Type | Single-ended, with bipolar range capability |
| Sample-and-Hold | On-chip |
| Self-Calibration | On-demand zero-scale and full-scale |
| Data Interface | Parallel word (DSP/microprocessor compatible) |
| Encapsulado | 24-pin CDIP (Ceramic DIP), 0.600 inch / 15.24 mm |
| Tipo de montaje | Through-hole |
| Rango de temperatura de funcionamiento | -40 C to +85 C |
| Technology | CMOS |
| Packaging | Tube |
| Recuento de pines | 24 |
| Temperature Grade | Industrial |
Configuración de pines de ADC1251CIJ
| Pin 1 | VCC — Positive analog supply (typically +5 V or +12 V) |
| Pin 2 | AGND — Analog ground |
| Pin 3 | REF — Reference voltage input |
| Pin 4 | AIN — Analog input |
| Pin 5 | S/H — Sample-and-hold control |
| Pin 6 | CAL — Calibration command input |
| Pin 7 | CS — Chip select |
| Pin 8 | RC — Read/Convert control |
| Pin 9 | BUSY — Conversion-in-progress status output |
| Pin 10 | CLK — External clock input |
| Pin 11 | DB11 (MSB) — Data bit 11 (Most Significant Bit) |
| Pin 12 | DB10 — Data bit 10 |
| Pin 13 | DB9 — Data bit 9 |
| Pin 14 | DB8 — Data bit 8 |
| Pin 15 | DB7 — Data bit 7 |
| Pin 16 | DB6 — Data bit 6 |
| Pin 17 | DB5 — Data bit 5 |
| Pin 18 | DB4 — Data bit 4 |
| Pin 19 | DB3 — Data bit 3 |
| Pin 20 | DB2 — Data bit 2 |
| Pin 21 | DB1 — Data bit 1 |
| Pin 22 | DB0 (LSB) — Data bit 0 (Least Significant Bit) |
| Pin 23 | SIGN — Sign bit output |
| Pin 24 | DGND — Digital ground |
Aplicaciones típicas
ADC1251CIJ es adecuado para 6 aplicacións: Industrial Process Control Data Acquisition, Precision Weigh Scale and Load Cell Digitizer, Portable Data Logging Front-End, Multichannel Instrumentation Panel, Medical Monitoring Front-End, Legacy Aerospace Avionics Retrofit.
Industrial Process Control Data Acquisition
The ADC1251CIJ fits industrial process control front-ends because its 12-bit plus sign resolution and on-demand self-calibration loop directly support closed-loop sensors measuring temperature, pressure, and flow. The 83 kSPS throughput exceeds the bandwidth of typical 4-20 mA or 0-10 V analog process loops, while the parallel-word output interfaces to industrial DSPs and microcontrollers without glue logic. The self-calibration feature eliminates manual trim of offset and gain after PCB assembly, reducing factory calibration time. The 24-CDIP ceramic package tolerates factory-floor temperature swings and conformal coating better than plastic surface-mount, which is critical in long-lifecycle process control racks.
Recomendado
Precision Weigh Scale and Load Cell Digitizer
The ADC1251CIJ's 12-bit plus sign resolution and bipolar input capability make it well-suited to digitize load-cell bridge outputs with zero and gain correction on every power-up. The on-chip sample-and-hold settles the bridge signal before conversion, suppressing high-frequency mechanical noise from the weigh platform. The self-calibration cycle corrects zero-scale drift caused by bridge aging and temperature, which would otherwise require periodic manual re-trim on the production line. The parallel interface streams conversion results directly to the indicator microcontroller, and the 24-CDIP package suits the through-hole, high-reliability construction typical of commercial scale electronics.
Recomendado
Portable Data Logging Front-End
The ADC1251CIJ suits portable battery-powered data loggers because the CMOS process holds quiescent dissipation low while delivering 83 kSPS throughput on demand. The self-calibration cycle runs once at power-up and once after a major temperature shift, avoiding continuous-power overhead typical of chopper-stabilized ADCs. The single analog input channel maps cleanly to a single-channel handheld instrument such as a thermometer, sound-level meter, or environmental monitor. The parallel output keeps the firmware straightforward on small 8-bit microcontrollers without needing an I2C or SPI ADC controller engine. The 24-CDIP package remains popular in legacy handheld designs where through-hole assembly is preferred.
Recomendado
Multichannel Instrumentation Panel
The ADC1251CIJ can be paralleled with external analog multiplexers to build a multichannel instrumentation panel for laboratory and rack-mount test equipment. Each channel is sampled by the on-chip sample-and-hold, and the parallel interface streams to a backplane microcontroller or DSP. The 83 kSPS rate supports scanning of 8-16 multiplexed channels at aggregate update rates of 5-10 kSPS per channel, which is sufficient for benchtop DMMs, panel meters, and process transmitters. The self-calibration function compensates for mux-on-resistance drift and input-bias-current errors, which is critical when channel counts grow beyond a few. The 24-CDIP ceramic package suits through-hole backplane cards preferred in industrial instrumentation.
Recomendado
Medical Monitoring Front-End
The ADC1251CIJ is suited to medical monitoring devices that digitize physiological signals from sensors such as temperature probes, pulse oximeters, and respiration belts. Its 12-bit plus sign resolution captures the bipolar AC waveform of respiration or pulse while preserving DC baseline, and the on-chip sample-and-hold prevents aperture-time distortion during burst-mode sampling. The self-calibration cycle keeps accuracy stable across the device's service life, supporting medical regulatory traceability. The parallel output integrates with DSP processors running real-time patient-monitoring algorithms. The ceramic 24-CDIP package supports through-hole, conformal-coated medical PCBs common in patient-side equipment.
Recomendado
Legacy Aerospace Avionics Retrofit
The ADC1251CIJ is often found in long-lifecycle avionics retrofit programs where original through-hole, ceramic-dip ADC slots must be re-populated. The 24-CDIP ceramic package, -40 C to +85 C industrial temperature range, and TI/NSC datasheet heritage make it attractive for line-replaceable units that must accept a form-fit-function replacement decades after the original build. The self-calibration cycle supports in-system accuracy refresh without removing the LRU from the airframe. The parallel-word output connects directly to legacy 8-bit and 16-bit databus interfaces, avoiding firmware changes on retired processor cards. This is a niche but enduring application for the part.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para ADC1251CIJ — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | AD574AJN | AD677AJN |
|---|---|---|---|
| Brand | Texas Instruments (ex-National Semiconductor) | Analog Devices | Analog Devices |
| Package | 24-CDIP (ceramic DIP, 0.600 in) | 24-CDIP (ceramic DIP) | 24-CDIP (ceramic DIP) |
| Resolution | 12 bit + sign | 12 bit | 16 bit |
| Sampling Rate | 83 kSPS | 35 kSPS | 100 kSPS |
| Architecture | SAR with on-chip sample-and-hold | SAR with on-chip sample-and-hold | SAR with on-chip sample-and-hold |
| On-Demand Self-Calibration | Yes (zero-scale and full-scale) | No (factory-trim only) | Yes (internal calibration) |
| Data Interface | Parallel word (12 bits + sign) | Parallel word (12 bits) | Serial (16 bits) |
| Lifecycle Status | Obsolete (TI last-time-buy) | Mature / legacy | Mature / legacy |
Diferenciadores clave
- On-demand self-calibration cycle (frente a AD574AJN)
- 12-bit plus sign bipolar operation (frente a AD574AJN)
- Higher sampling rate (frente a AD574AJN)
Notas de diseño
The ADC1251CIJ requires a clean analog supply and a separate digital supply if used; bypass both supply pins with a 10 uF tantalum in parallel with a 0.1 uF ceramic as close to the package pins as possible. Reference the analog and digital grounds at one star point near the IC, and never run digital return currents through the analog ground trace. A precision external reference such as TL431ACDBZR will hold conversion gain error well below the datasheet maximum and is required to realize the on-chip calibration's full benefit.
Route the analog input trace as a guarded, low-impedance path and keep it away from digital output bus lines DB0-DB11 to avoid coupling digital switching noise into the analog sample-and-hold. Keep the CLK trace short to prevent radiated EMI from coupling onto the analog front end. If you must cross analog and digital traces, do so at right angles. Place the reference decoupling capacitor directly across the REF and AGND pins with the shortest possible trace length to keep reference noise below the converter's LSB.
Do not skip the on-demand self-calibration cycle after power-up; without it the published accuracy specifications do not apply. Do not toggle the RC pin while BUSY is asserted, which will abort the conversion. Do not operate the analog input beyond the absolute-maximum rating specified in the datasheet; overdrive at the input pin can permanently damage the sample-and-hold capacitor. When substituting a cross-brand 24-CDIP ADC (AD574AJN, AD677AJN), confirm the pinout before soldering because some ceramic-DIP SAR ADCs differ in supply, reference, and analog input pin assignments.
Información de cumplimiento
ADC1251CIJ is a legacy ceramic-DIP part from the National Semiconductor era; current RoHS/REACH/lead-free status for the ceramic-DIP variant is not stated in the provided data and is marked [DATA_NEEDED] in the specs. AEC-Q100 is not applicable - this is an industrial-grade part, not automotive qualified.
