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Analog Devices Inc. AD678KD
- Part No.:
- AD678KD
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 28-CDIP (0.600", 15.24mm)
- Datasheet:
-
AD678KD.pdf
- Description:
- IC ADC 12BIT FLASH 28CDIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,175
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Product details
Overview
AD678KD from Analog Devices is a complete 12-bit, 200 kSPS monolithic sampling analog-to-digital converter with integrated sample-hold amplifier, on-chip 5 V reference, clock generation, and dual-mode (8-/12-bit) parallel bus interface. It delivers 72 dB S/N+D (K/B/T grades), 1 MHz full-power bandwidth, and ±1 LSB integral nonlinearity over 0°C to +70°C - used in precision data acquisition systems for industrial instrumentation and automated test equipment.
For engineers reviewing the AD678KD datasheet, AD678KD pinout, AD678KD application, or AD678KD equivalent, this page provides verified technical context, validated pin functions, confirmed DC/AC specifications across K-grade operation, and real-world interface timing constraints for synchronous/asynchronous control modes.
Technical Context
The AD678KD implements a recursive subranging architecture combining flash conversion stages with error correction logic to achieve 12-bit resolution at 200 kSPS. Its sample-hold amplifier supports 1 µs input settling time and 150 ps aperture jitter, enabling accurate digitization of signals up to 1 MHz full-power bandwidth.
It operates from three independent supplies (+12 V, –12 V, +5 V), integrates laser-trimmed thin-film resistors for dc accuracy, and supports both unipolar (0–10 V, straight binary) and bipolar (±5 V, twos complement) input ranges with factory-trimmed offset and gain errors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - defines quantization step size of 2.44 mV in 10 V range, enabling sub-millivolt measurement resolution. |
| Sampling Rate | 200 kSPS - supports real-time capture of signals up to 100 kHz Nyquist frequency without undersampling artifacts. |
| S/N+D Ratio | 72 dB (K-grade) - ensures ≥11.6 effective bits of dynamic performance for low-noise signal processing applications. |
| Full-Power Bandwidth | 1 MHz - allows direct digitization of fast transients or RF IF signals without external anti-alias filtering below 1 MHz. |
| Integral Nonlinearity | ±1 LSB max - guarantees monotonicity and absence of missing codes across full temperature range (0°C to +70°C). |
| Input Impedance | 10 MΩ - permits direct connection to high-impedance sensors or multiplexer outputs without loading-induced gain error. |
| Reference Output | 4.98–5.02 V - stable internal voltage reference enables ratiometric measurements and eliminates need for external reference IC. |
Pinout & Package
AD678KD is housed in a 28-lead ceramic DIP (package option D-28), with pins arranged for analog/digital signal isolation: analog power (VCC, VEE), analog ground (AGND), digital ground (DGND), and dedicated analog input (AIN) and reference (REFIN, REFOUT) pins grouped together.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AIN | Analog Signal Input | High-impedance (10 MΩ) node accepting 0–10 V unipolar or ±5 V bipolar full-scale inputs; connects directly to sensor or signal chain output. |
| BIPOFF | Bipolar Offset Control | Selects operating mode: tied to AGND for unipolar (straight binary); tied to REFOUT via 50 Ω for bipolar (twos complement) coding. |
| CS | Chip Select | Active-low enable for synchronous mode - must be asserted before SC to minimize aperture delay and ensure valid conversion start. |
| SC | Start Convert | Active-low trigger initiating conversion cycle; in asynchronous mode (SYNC = LOW), operates independently of CS. |
| OE | Output Enable | Falling edge enables DB11–DB0 outputs in 12-bit mode or DB11–DB4 in 8-bit mode; gated with CS in synchronous operation. |
| EOC | End-of-Convert Status | Open-drain (asynchronous) or three-state (synchronous) flag indicating conversion completion; used for interrupt-driven data reads. |
| 12/8 | Output Format Select | Logic HIGH configures 12-bit parallel output on DB11–DB0; LOW enables 8-bit multiplexed read (high byte then low byte). |
| VCC / VEE / VDD | Analog/Digital Power Supplies | +12 V / –12 V analog rails and +5 V digital rail - require local decoupling (10 µF + 0.1 µF) to AGND to maintain AC performance. |
Key Features
| Feature | Design Value |
|---|---|
| Complete On-Chip Functionality | Integrates sample-hold amplifier, 12-bit ADC core, 5 V reference, clock generator, and microprocessor-compatible interface - eliminates 12+ external components in discrete designs. |
| Factory Laser Trimming | Delivers guaranteed ±1 LSB INL and ±4 LSB gain error over 0°C to +70°C without field calibration or external trimmers. |
| Dual Bus Interface Flexibility | Supports both 16-bit single-cycle (12-bit) and 8-bit two-cycle (8+4) reads with right/left justification - simplifies integration with legacy 8-bit microcontrollers or modern 16-bit DSPs. |
| Robust Input Architecture | 10 MΩ input impedance and 1 µs settling time allow direct connection to multiplexers with ≤1000 Ω channel mismatch - avoids buffer amplifiers and associated noise/error sources. |
| MIL-STD-883 Screening Option | AD678KD meets Class B screening per MIL-STD-883C - qualified for use in military/aerospace programs requiring extended reliability validation. |
Applications
| Industrial Process Monitoring | Automated Test Equipment (ATE) |
|---|---|
Use Scenario: Continuous voltage/current monitoring of PLC I/O modules and sensor transmitters in factory automation systems. IC Role / Device Role / Timing Role: Primary sampling ADC capturing 4–20 mA loop signals conditioned to 0–10 V range at 100 kSPS for real-time control feedback. Use Value: ±1 LSB INL and 72 dB S/N+D ensure <0.025% measurement uncertainty across 0–70°C, meeting IEC 61000-4-3 immunity requirements. |
Use Scenario: Digitizing stimulus response waveforms during functional testing of mixed-signal ICs on production test handlers. IC Role / Device Role / Timing Role: High-fidelity acquisition front-end synchronized to pattern generator clocks for 12-bit waveform capture at 200 kSPS. Use Value: 1 MHz full-power bandwidth enables accurate capture of fast-edged test pulses without aliasing; on-chip reference eliminates external reference drift errors. |
| Avionics Data Acquisition | Medical Diagnostic Instrumentation |
Use Scenario: Recording analog sensor outputs (pressure, temperature, vibration) in flight data recorders and engine health monitoring units. IC Role / Device Role / Timing Role: Ruggedized ADC operating from –55°C to +125°C variants (T-grade), interfaced to isolated serial buses via FPGA glue logic. Use Value: Ceramic DIP package and MIL-STD-883 compliance provide proven reliability in high-vibration, radiation-prone environments per DO-160E Section 21. |
Use Scenario: Digitizing ECG, EEG, and bio-potential signals in portable diagnostic devices where size, power, and accuracy are critical. IC Role / Device Role / Timing Role: Low-noise, high-Z input stage acquiring microvolt-level biopotentials with programmable gain and bipolar input range. Use Value: 150 ps aperture jitter and 500 kHz full-linear bandwidth preserve waveform fidelity of cardiac QRS complexes and neural spikes without slew-induced distortion. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit sampling ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD678KN | Same die, plastic DIP package; AC-only specification (no guaranteed DC parameters like INL or gain error). | Suitable for cost-sensitive signal processing where only S/N+D and THD matter - not for precision measurement requiring guaranteed linearity. | Select AD678KN only when operating temperature is strictly 0°C to +70°C and dc accuracy is not required. |
| AD7874BQ | 12-bit, 100 kSPS; no on-chip reference or clock; requires external REF and master clock; ±0.5 LSB INL (tighter), but lower speed. | Better suited for low-power, low-noise DC-coupled applications (e.g., weigh scales) where throughput >100 kSPS is unnecessary. | Choose AD7874BQ when system already provides precision reference and clock, and 100 kSPS suffices for application timing budget. |
Compared with AD678KN and AD7874BQ, the AD678KD uniquely combines guaranteed DC accuracy (±1 LSB INL), integrated reference/clock, and 200 kSPS throughput in a screened ceramic package - making it the only choice for mil-spec data loggers requiring full ac/dc characterization at temperature extremes.
Availability
AD678KD is available at Aetrix Electronics and suitable for industrial process monitoring, avionics data acquisition, and automated test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for AD678KD 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 series was designed as a fully integrated, drop-in replacement for hybrid ADC modules in military and industrial instrumentation - emphasizing on-chip integration, factory-trimmed dc accuracy, and rugged packaging for harsh environments.
FAQ
What is the operating temperature range for the AD678KD?
The AD678KD is rated for operation from 0°C to +70°C. This K-grade commercial temperature range is fully specified for both AC (S/N+D, THD) and DC (INL, gain error, zero error) parameters, unlike J-grade variants which specify AC performance only. The AD678KD's ceramic DIP package ensures mechanical stability across this range without derating.
Does the AD678KD require external clock circuitry?
No, the AD678KD includes on-chip clock generation circuitry and does not require an external clock source. Its internal oscillator supports the full 200 kSPS sampling rate. External clocking is not supported - timing is controlled solely by the SC (Start Convert) input in conjunction with SYNC and CS signals.
How is bipolar vs. unipolar mode selected on the AD678KD?
Bipolar or unipolar mode is selected via the BIPOFF pin: connect BIPOFF to AGND for unipolar input (0–10 V, straight binary output); connect BIPOFF to REFOUT through a 50 Ω resistor for bipolar input (±5 V, twos complement output). This configuration also determines the data coding format and full-scale range.
Can the AD678KD interface directly with an 8-bit microcontroller bus?
Yes, the AD678KD supports 8-bit multiplexed read mode via the 12/8 pin. When 12/8 is LOW, DB11–DB4 carry the upper 8 bits, while DB1 (R/L) and DB0 (HBE) become control inputs to sequence high-byte/low-byte reads. This eliminates need for external latches or data buffers when interfacing with 8-bit processors.
What power supply voltages does the AD678KD require?
The AD678KD requires three independent supplies: +12 V (VCC), –12 V (VEE), and +5 V (VDD). These must be well-decoupled (10 µF tantalum + 0.1 µF ceramic per supply pin to AGND) to maintain specified AC performance. Supply rejection is ±2 LSB per ±5% variation on VCC/VEE and ±10% on VDD.
AD678KD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-CDIP (0.600", 15.24mm)
- Packaging:
- Bulk
- 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:
- 0°C ~ 70°C
- Supplier Device Package:
- 28-CDIP
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
AD678KD FAQ
1.How can I place an order for AD678KD through Aetrix?
Please submit a Request for Quotation (RFQ) for AD678KD 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 AD678KD reliable?
The price and inventory of AD678KD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD678KD is usually 5 days.
3.What payment methods are accepted for AD678KD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD678KD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD678KD?
AD678KD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD678KD 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 AD678KD?
For technical support, including AD678KD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD678KD requirements.
6.How does Aetrix verify that AD678KD is sourced from the original manufacturer or authorized distributors?
All AD678KD 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 AD678KD meets industry standards.
7.What is the process for return or replacement of AD678KD?
All AD678KD units undergo pre-shipment inspection (PSI). If there is an issue with AD678KD, 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 AD678KD part is unused and in its original packaging.
Return procedure for AD678KD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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