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Analog Devices Inc. AD678BD
- Part No.:
- AD678BD
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 28-CDIP (0.600", 15.24mm)
- Datasheet:
-
AD678BD.pdf
- Description:
- IC ADC 12BIT FLASH 28CDIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,140
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Product details
Overview
AD678BD from Analog Devices is a complete 12-bit monolithic sampling analog-to-digital converter (ADC) integrating sample-hold amplifier, voltage reference, clock generation, and microprocessor-compatible bus interface. It delivers 200 kSPS throughput, 1 MHz full-power bandwidth, 72 dB S/N+D (B grade), ±0.7 LSB INL, and operates across –40°C to +85°C for industrial measurement and signal acquisition systems.
For engineers reviewing the AD678BD datasheet, AD678BD pinout, AD678BD application, or AD678BD equivalent, this page provides verified technical context, validated pin functions, real-world use cases in precision data acquisition, and confirmed alternatives with documented functional and application-level differences.
Technical Context
The AD678BD employs a recursive subranging architecture with integrated 4-bit flash ADC and 12-bit DAC for error correction, enabling high-speed, high-accuracy conversion without external calibration. Its BiMOS process combines CMOS logic and bipolar analog circuits with laser-trimmed thin-film resistors for stable dc performance.
It supports dual digital interface modes: 12-bit parallel output (via DB11–DB0) or 8-bit multiplexed output (DB11–DB4 with R/L and HBE control), with straight binary (unipolar) or twos complement (bipolar) coding. Input range is selectable between 0–10 V or ±5 V, with 10 MΩ input impedance and 1 µs settling time.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - defines 4096 discrete output codes for precise amplitude quantization. |
| Sampling Rate | 200 kSPS - enables real-time capture of signals up to 100 kHz Nyquist frequency. |
| S/N+D Ratio | 72 dB (B grade) - ensures ≥11.6 effective bits for low-noise signal analysis. |
| INL | ±0.7 LSB (B grade) - guarantees monotonicity and <0.017% full-scale linearity error. |
| Input Range | 0–10 V unipolar or ±5 V bipolar - supports direct connection to sensors and instrumentation outputs. |
| Full-Power BW | 1 MHz - allows accurate digitization of fast transients without slew-induced distortion. |
| Supply Voltages | +12 V (VCC), –12 V (VEE), +5 V (VDD) - separates analog and digital domains to minimize noise coupling. |
Pinout & Package
AD678BD is housed in a 28-lead ceramic DIP (package option D-28), rated for –40°C to +85°C operation and MIL-STD-883 screening capability. Pin layout isolates analog (AGND, AIN, VCC, VEE, REFIN, REFOUT, BIPOFF) and digital (DGND, CS, SC, OE, EOCEN, SYNC, DBn, 12/8, R/L, HBE) sections to suppress crosstalk.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AIN | Analog Input | High-impedance (10 MΩ) node accepting 0–10 V or ±5 V signals directly from sensors or amplifiers. |
| AGND | Analog Ground | Dedicated return path for AIN only; must be isolated from DGND to prevent digital noise injection. |
| VCC / VEE | Analog Power Supplies | +12 V and –12 V rails power SHA, reference, and analog core; require local 10 µF + 0.1 µF decoupling. |
| VDD | Digital Power | +5 V supply for logic and output drivers; decoupled separately from analog supplies. |
| CS / SC / OE / EOCEN / SYNC | Digital Control Inputs | TTL/CMOS-compatible inputs managing conversion start, output enable, status gating, and interface mode selection. |
| DB11–DB0 | Data Outputs | Three-state parallel outputs delivering 12-bit result; configurable for 12-bit or 8-bit bus interfacing via 12/8, R/L, and HBE pins. |
| REFOUT / REFIN / BIPOFF | Reference Interface | On-chip 5 V reference (REFOUT) sets full-scale range; BIPOFF selects unipolar/bipolar mode via resistor network. |
| EOC | Status Output | Open-drain (asynchronous) or three-state (synchronous) flag indicating conversion completion. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Sample-Hold + Reference + Clock | Eliminates 5+ external components versus discrete ADC designs, reducing board area and calibration complexity. |
| Factory Laser-Trimmed INL/Gain/Offset | Enables guaranteed ±0.7 LSB INL and ±3 LSB gain error (B grade) without user calibration. |
| Dual Bus Interface Mode (12-bit or 8-bit) | Supports legacy 8-bit microcontrollers and modern 16-bit processors without interface redesign. |
| Bipolar/Unipolar Input Flexibility | Single device serves both signed (e.g., vibration, audio) and unsigned (e.g., temperature, pressure) sensor interfaces. |
| MIL-STD-883 Screening Option | Enables deployment in aerospace and defense systems requiring extended reliability validation. |
Applications
| Industrial Process Monitoring | Test & Measurement Equipment |
|---|---|
Use Scenario: Continuous digitization of 4–20 mA current loop outputs converted to voltage via precision shunt in PLC I/O modules. IC Role / Device Role / Timing Role: Primary sampling ADC acquiring analog sensor data at 100 kSPS with <1 µs settling for closed-loop control feedback. Use Value: 12-bit resolution and ±0.7 LSB INL ensure <0.02% full-scale accuracy across –40°C to +85°C ambient, meeting IEC 61000-6-2 immunity requirements. | Use Scenario: Digitizing waveform outputs from function generators and arbitrary waveform sources in benchtop oscilloscopes and spectrum analyzers. IC Role / Device Role / Timing Role: High-fidelity front-end ADC capturing transient signals with 1 MHz full-power bandwidth and 72 dB S/N+D. Use Value: 10 MΩ input impedance prevents loading of high-Z sources; 500 kHz full-linear bandwidth preserves harmonic integrity up to 5th order. |
| Avionics Sensor Acquisition | Medical Diagnostic Instrumentation |
Use Scenario: Converting outputs from accelerometers, gyros, and pressure transducers in flight data recorders and health monitoring units. IC Role / Device Role / Timing Role: Ruggedized ADC operating over –40°C to +85°C with MIL-STD-883 screening support for airborne environments. Use Value: Ceramic DIP package and BiMOS process deliver long-term parametric stability under thermal cycling and vibration stress. | Use Scenario: Sampling ECG, EEG, and EMG bio-potential signals amplified by low-noise instrumentation amplifiers in patient monitors. IC Role / Device Role / Timing Role: Precision ADC providing 12-bit resolution and low THD (–80 dB) to preserve diagnostic waveform fidelity. Use Value: Bipolar ±5 V input range matches differential amplifier outputs; 150 ps aperture jitter minimizes SNR degradation in multi-channel synchronized acquisition. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar sampling ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD678KD | Same 28-lead ceramic DIP package and –40°C to +85°C rating, but K grade specifies AC+DC parameters at 0°C to +70°C only. | Not qualified for industrial temperature range; limited to commercial-grade systems with controlled ambient. | Select AD678BD when full industrial temperature validation and guaranteed ±0.7 LSB INL across –40°C to +85°C are required. |
| AD679BD | 14-bit, 128 kSPS ADC with identical 28-lead ceramic DIP pinout; higher resolution but lower speed and different internal reference architecture. | Used where resolution > speed (e.g., static calibration standards); incompatible timing and register mapping for drop-in replacement. | Choose AD678BD for 200 kSPS throughput and 12-bit precision in dynamic signal capture; AD679BD only if 14-bit resolution justifies 36% speed reduction. |
Compared with AD678KD, AD678BD provides validated dc accuracy over the full industrial temperature range; compared with AD679BD, it trades 2-bit resolution for 56% higher sampling rate and maintains compatibility with existing AD678-based layouts while delivering superior dynamic performance at high frequencies.
Availability
AD678BD is available at Aetrix Electronics and suitable for industrial process monitoring, test & measurement equipment, avionics sensor acquisition, medical diagnostic instrumentation, and precision data logging requiring stable component supply across extended temperature ranges.
Supply support for AD678BD includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, founded in 1965 and headquartered in Wilmington, MA.
The AD678 product line was designed as a fully integrated, self-contained sampling ADC family for high-accuracy data acquisition in industrial, military, and instrumentation applications where minimal external components and guaranteed ac/dc specifications are critical.
FAQ
What is the operating temperature range specified for the AD678BD?
The AD678BD is rated for continuous operation from –40°C to +85°C, with full AC and DC parameter specifications guaranteed across this industrial temperature range. This includes validated performance for integral nonlinearity (±0.7 LSB), gain error (±3 LSB), and S/N+D ratio (72 dB) at both extremes, making it suitable for harsh-environment deployments where thermal stability is critical.
Does the AD678BD require external calibration to achieve its specified accuracy?
No, the AD678BD does not require external calibration to meet its datasheet specifications. It undergoes factory laser trimming of thin-film resistors to guarantee ±0.7 LSB integral nonlinearity, ±3 LSB gain error, and ±3 LSB bipolar zero error across –40°C to +85°C. Only optional fine-tuning (e.g., for <±1 LSB residual error) requires external potentiometers per the AD678BD application note.
How does the AD678BD handle analog input impedance and signal source compatibility?
The AD678BD features a 10 MΩ analog input impedance, allowing direct connection to high-impedance sources such as piezoelectric sensors, thermocouples with cold-junction compensation ICs, and unbuffered multiplexer outputs without signal degradation. Its 1 µs input settling time ensures full 12-bit accuracy even after full-scale step inputs, eliminating need for external op-amp buffers in most industrial sensor interfaces.
Can the AD678BD interface with an 8-bit microcontroller bus?
Yes, the AD678BD supports 8-bit bus interfacing via its multiplexed output mode. When the 12/8 pin is pulled LOW, the 12-bit result is read in two 8-bit cycles: DB11–DB4 carry the high byte (controlled by HBE), then the low byte. The R/L pin selects right- or left-justified alignment within the 16-bit field, enabling seamless integration with legacy 8-bit systems without data loss or software overhead.
What power supply configuration is required for proper operation of the AD678BD?
The AD678BD requires three independent supplies: +12 V (VCC), –12 V (VEE), and +5 V (VDD). VCC and VEE power the analog section (SHA, reference, DAC), while VDD powers digital logic and outputs. Each supply must be locally decoupled with a 10 µF tantalum capacitor in parallel with a 0.1 µF ceramic capacitor, connected directly to AGND (analog) or DGND (digital) as specified-mixing grounds degrades S/N+D by up to 10 dB.
AD678BD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-CDIP (0.600", 15.24mm)
- Packaging:
- Tube
- Product Status:
- Active
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 200k
- Number of Inputs:
- 1
- Input Type:
- Single Ended
- Data Interface:
- Parallel
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- Flash
- Reference Type:
- Internal
- Voltage - Supply, Analog:
- ±12V
- Voltage - Supply, Digital:
- 5V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 28-CDIP
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
AD678BD FAQ
1.How can I place an order for AD678BD through Aetrix?
Please submit a Request for Quotation (RFQ) for AD678BD on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for AD678BD reliable?
The price and inventory of AD678BD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD678BD is usually 5 days.
3.What payment methods are accepted for AD678BD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD678BD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD678BD?
AD678BD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD678BD order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for AD678BD?
For technical support, including AD678BD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD678BD requirements.
6.How does Aetrix verify that AD678BD is sourced from the original manufacturer or authorized distributors?
All AD678BD products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that AD678BD meets industry standards.
7.What is the process for return or replacement of AD678BD?
All AD678BD units undergo pre-shipment inspection (PSI). If there is an issue with AD678BD, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The AD678BD part is unused and in its original packaging.
Return procedure for AD678BD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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