AD678JN - 12-Bit 200 kSPS Complete Sampling ADC | Analog Devices
N.º da peça: AD678JN ✗ Fim de vidaAD678JN Visão geral
An ADC is an interface IC that converts a continuously varying analog voltage into a numeric representation. Within the broader signal-chain hierarchy, the AD678JN belongs to the ADC/DAC class of data-conversion semiconductors, where it sits between sensors or front-end amplifiers and a microprocessor, DSP, or controller. The complete sampling ADC designation means that the major supporting functions are integrated rather than implemented as separate external components.
The AD678's key characteristics include 12-bit resolution, a 200 kSPS sampling rate, a microprocessor-compatible interface, an internal voltage reference, and integrated clock circuitry. Dynamic performance parameters such as signal-to-noise plus distortion ratio, total harmonic distortion, and intermodulation distortion are important when the converter handles dynamic or AC signals. The manufacturer states that the AD678 shares the same pinout as the 14-bit, 128 kSPS AD679 ADC, providing a useful migration path when higher resolution is required without changing the board layout.
The device is suitable for industrial data acquisition, process monitoring, waveform measurement, communications equipment, and control systems. Its parallel word-oriented output can connect directly to suitable microprocessor or digital signal processor buses, while the integrated sample-and-hold stage simplifies front-end signal acquisition. System designers should still budget acquisition time, input bandwidth, reference accuracy, digital-interface timing, and analog settling time around the sampling instant.
A critical layout consideration is keeping the analog input path short and quiet. The input, reference, and digital return connections should follow the pin-description and layout guidance in the manufacturer datasheet, with care taken to minimize coupling from the parallel data bus into the sensitive input node. The AD678 is a legacy through-hole device, so its DIP footprint also makes it practical for prototyping, maintenance, and repair systems where surface-mount assembly is not required.
This page combines the manufacturer product information, exact AD678JN listing data, package details, application guidance, and documented upgrade paths. It also distinguishes verified drop-in candidates from parts that require package or functional review, helping engineers evaluate the AD678JN for new designs and legacy replacements.
Alternativas drop-in para AD678JN — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Variantes desta série
Modelos da mesma série compatíveis como drop-in com AD678JN (mesmo formato e footprint) — diferindo em Package, Architecture, Voltage Reference, Mounting Type, Resolution.
AD678JNZ
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
AD679KD
✅ Drop-InConsulte o preço
Ver ficha técnica →AD678KD
✅ Drop-InConsulte o preço
Ver ficha técnica →AD678JD
✅ Drop-InConsulte o preço
Ver ficha técnica →AD678AD
✅ Drop-InConsulte o preço
Ver ficha técnica →AD678JN Classificações máximas e características elétricas
| ADC Resolution | 12 bit |
| Taxa de amostragem | 200 kSPS |
| Architecture | Flash |
| Converter Type | Complete sampling ADC |
| Analog Input Type | Single-ended |
| Channel Count | 1 channel |
| Digital Interface | Parallel, microprocessor compatible |
| Data Word Width | 12 bit |
| Integrated Functions | Sample-and-hold amplifier, microprocessor-compatible bus interface, voltage reference, and clock generation circuitry |
| Encapsulamento | 28-pin PDIP |
| Tipo de montagem | Through-hole |
| AD679 Upgrade Path Pinout | Same pinout as 14-bit, 128 kSPS AD679 |
| Military Product Availability | Versions compliant with MIL-STD-883 |
| Dynamic Performance Parameters | SN+D, THD, and IMD |
Guia de Configuração de Pinos do AD678JN 28-pin pdip
Configuração de pinos para AD678JN (pacote 28-pin pdip). Este componente analógico possui pinos de entrada, saída e alimentação. Consulte o datasheet do fabricante para configurações de offset null, compensação e pino de enable. Ideal para circuitos de condicionamento de sinal e amplificadores.
Nenhum dado detalhado de pinagem disponível para AD678JN.
Consulte a ficha técnica para a configuração completa dos pinos.
Aplicações típicas
AD678JN é adequado para 6 aplicaçãos: Industrial Process Monitoring, Digital Oscilloscope and Waveform Capture, Communications Signal Conditioning, Data Acquisition and Control Systems, Audio and Vibration Analysis, Legacy Instrumentation Repair and Retrofit.
Industrial Process Monitoring
The AD678JN suits industrial process-monitoring systems that need to digitize pressure, temperature, level, or position signals at up to 200 kSPS. Its 12-bit resolution gives 4096 digital codes, while the integrated sample-and-hold amplifier, voltage reference, and clock generation simplify the acquisition section around the converter. The 28-pin PDIP format also suits legacy production equipment and field-retrofit boards. The designer should apply analog filtering ahead of the input, keep the analog trace short, and define how sensor excitation drift, reference accuracy, and electrical noise affect the final measurement resolution.
Recomendado
Digital Oscilloscope and Waveform Capture
The AD678JN can serve as the sampling front end in a digital oscilloscope, waveform recorder, or vibration-analysis instrument. Its 200 kSPS sampling capability captures rapidly changing analog events, while the 12-bit output provides useful dynamic range without requiring a high-resolution ADC. The parallel interface permits direct transfer to a processor or DSP when bus timing is properly designed. Practical bandwidth still depends on the sample-and-hold aperture, input bandwidth, analog front-end gain, anti-alias filtering, memory speed, and signal-to-noise performance, so the complete acquisition chain should be characterized rather than relying on conversion rate alone.
Recomendado
Communications Signal Conditioning
The AD678JN is applicable to communications and telemetry equipment that converts a conditioned analog waveform into a 12-bit parallel digital stream. Its single-channel, 200 kSPS architecture fits low- or moderate-bandwidth modulation and monitoring functions where a microprocessor or DSP performs demodulation and filtering. The converter’s dynamic specifications, including SN+D, THD, and IMD, are the relevant selection criteria for AC performance. A practical design must account for the parallel bus’s switching noise, clock-edge timing, input drive impedance, and the amplitude range required to use the converter’s full code range without clipping.
Recomendado
Data Acquisition and Control Systems
The AD678JN fits legacy data-acquisition and embedded-control systems requiring a deterministic parallel ADC with 12-bit data and a 200 kSPS conversion rate. A microprocessor can read the converter output and initiate the next acquisition, while the integrated reference and clock circuitry reduce board complexity. For closed-loop equipment, the analog input bandwidth must be high enough for the required loop dynamics, and the digital interface must avoid contention or timing violations around read and conversion-control signals. Firmware should also include range checks, calibration coefficients, and fault handling for out-of-range sensor conditions.
Recomendado
Audio and Vibration Analysis
The AD678JN can be used in audio test equipment, vibration analyzers, and condition-monitoring modules where a 12-bit, 200 kSPS converter is adequate for capturing dynamic waveforms. The sample-and-hold function supports repetitive acquisition, while the parallel output allows rapid transfer into a DSP or embedded processor for filtering and spectral analysis. Because the converter is not a dedicated audio delta-sigma part, designers should evaluate noise, distortion, input full-scale range, and anti-alias behavior over the intended audio band. Shielding, grounding, and separation from digital switching circuitry are especially important in vibration systems with long sensor cables.
Recomendado
Legacy Instrumentation Repair and Retrofit
The 28-pin PDIP AD678JN is particularly relevant to maintenance and obsolescence-management programs for older measurement instruments, controllers, and laboratory equipment. Its through-hole package is mechanically accessible for repair, and the documented AD678-to-AD679 pin compatibility offers a defined upgrade path for systems needing more resolution. Before replacing an installed device, compare the original suffix’s temperature grade, supply requirements, reference behavior, and timing with the selected replacement. Board-level qualification should also include a power-up sequence test, known-input accuracy test, and verification of every parallel output bit.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para AD678JN — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | AD678JNZ | AD679KD | AD678KD | AD678JD | AD678AD |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 28-pin PDIP | 28-pin PDIP | 28-pin PDIP | 28-pin PDIP | 28-pin PDIP | 28-pin PDIP |
| Resolution | 12 bit | 12 bit | 14 bit | 12 bit | 12 bit | 12 bit |
| Sampling Rate | 200 kSPS | 200 kSPS | 128 kSPS | 200 kSPS | 200 kSPS | 200 kSPS |
| Channel Count | 1 channel | 1 channel | 1 channel | 1 channel | 1 channel | 1 channel |
| Interface | Parallel, microprocessor compatible | Parallel, microprocessor compatible | Parallel | Parallel, microprocessor compatible | Parallel | Parallel |
| Documented Upgrade Path | AD679 shares the AD678 pinout | Same AD678 family | AD679 shares the AD678 pinout | Same AD678 family | Same AD678 family | Same AD678 family |
Principais diferenciais
- Faster conversion rate within the shared-pinout upgrade family (vs AD679KD)
- Higher native resolution in the documented AD679 upgrade path (vs AD678JN)
- Same-family replacement with matching conversion performance (vs AD678JNZ)
Notas de projeto
Route the analog input as a short, isolated trace and place the input filtering components close to the ADC. Keep the parallel data bus away from the input and reference nodes, and use a solid ground plane with short return paths. The AD678 is a flash converter, so switching activity on the digital output bus can couple into the sensitive analog input if routing and grounding are not controlled. Follow the pin-description table and recommended application circuit in the manufacturer datasheet when assigning every signal and grounding point.
Do not treat the AD679KD as a perfectly transparent AD678 replacement. The upgrade changes resolution from 12 bit to 14 bit and reduces the sampling rate from 200 kSPS to 128 kSPS, a 72 kSPS decrease. Existing firmware may need scaling changes, and acquisition timing or anti-alias filters may require recalculation. Although the pinout is shared, verify supply sequencing, control timing, output coding, and board-level signal integrity before production substitution.
The 12-bit parallel bus requires clean settling at the receiving device. Use short traces, matched topology where practical, and suitable termination or series damping according to the processor and processor-interface timing. Inspect the conversion strobe and data-read sequence in the manufacturer timing diagrams to determine whether data changes near the sampling edge. Where the bus is long or the board is electrically noisy, buffer or latch the output rather than routing the converter directly into a critical high-speed bus.
Decouple the ADC supply at the device with short, low-inductance connections and provide separate return paths for analog and digital currents. The internal voltage reference supports converter operation, but the complete acquisition chain still requires clean power to achieve predictable results. Confirm the exact supply voltage, tolerance, power-up sequence, and decoupling recommendations from the manufacturer datasheet for the selected AD678 suffix before finalizing the power architecture.
Informações de conformidade
Analog Devices states that versions of the AD678 are compliant with MIL-STD-883. RoHS, REACH, lead-free, halogen-free, and conflict-minerals status are not stated for AD678JN in the available product information.