ADC1251CIJ - 12-Bit+Sign Self-Calibrating SAR ADC | Texas Instruments
Référence : ADC1251CIJ ✗ Fin de vie| Qté | Prix unitaire | 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 Présentation
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.
Alternatives de remplacement direct pour ADC1251CIJ — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
ADC1251CIJ
✅ Remplacement direct✓ En stock
$10.95 / unité
Voir la fiche technique →AD574AJN
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
AD677AJN
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
ADC1251CIJ Valeurs maximales et caractéristiques électriques
| Résolution | 12 bit + sign |
| Architecture | SAR (Successive Approximation) |
| Number of Input Channels | 1 |
| Fréquence d'échantillonnage | 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) |
| Boîtier | 24-pin CDIP (Ceramic DIP), 0.600 inch / 15.24 mm |
| Type de montage | Through-hole |
| Plage de température de fonctionnement | -40 C to +85 C |
| Technology | CMOS |
| Packaging | Tube |
| Nombre de broches | 24 |
| Temperature Grade | Industrial |
Configuration des broches de ADC1251CIJ
| Broche 1 | VCC — Positive analog supply (typically +5 V or +12 V) |
| Broche 2 | AGND — Analog ground |
| Broche 3 | REF — Reference voltage input |
| Broche 4 | AIN — Analog input |
| Broche 5 | S/H — Sample-and-hold control |
| Broche 6 | CAL — Calibration command input |
| Broche 7 | CS — Chip select |
| Broche 8 | RC — Read/Convert control |
| Broche 9 | BUSY — Conversion-in-progress status output |
| Broche 10 | CLK — External clock input |
| Broche 11 | DB11 (MSB) — Data bit 11 (Most Significant Bit) |
| Broche 12 | DB10 — Data bit 10 |
| Broche 13 | DB9 — Data bit 9 |
| Broche 14 | DB8 — Data bit 8 |
| Broche 15 | DB7 — Data bit 7 |
| Broche 16 | DB6 — Data bit 6 |
| Broche 17 | DB5 — Data bit 5 |
| Broche 18 | DB4 — Data bit 4 |
| Broche 19 | DB3 — Data bit 3 |
| Broche 20 | DB2 — Data bit 2 |
| Broche 21 | DB1 — Data bit 1 |
| Broche 22 | DB0 (LSB) — Data bit 0 (Least Significant Bit) |
| Broche 23 | SIGN — Sign bit output |
| Broche 24 | DGND — Digital ground |
Applications typiques
ADC1251CIJ convient pour 6 applications: 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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour ADC1251CIJ — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | 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 |
Principaux différenciateurs
- On-demand self-calibration cycle (vs AD574AJN)
- 12-bit plus sign bipolar operation (vs AD574AJN)
- Higher sampling rate (vs AD574AJN)
Notes de conception
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.
Informations de conformité
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.
