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Analog Devices Inc. AD774BTD
- Part No.:
- AD774BTD
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 28-CDIP (0.600", 15.24mm)
- Datasheet:
-
AD774BTD.pdf
- Description:
- IC ADC 12BIT SAR 28CDIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,256
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Product details
Overview
AD774BTD from Analog Devices is a complete monolithic 12-bit successive-approximation analog-to-digital converter (ADC) with on-chip 10 V reference, clock generator, and three-state digital output buffers. It operates across –55°C to +125°C, supports 0 V–10 V / 0 V–20 V / ±5 V / ±10 V input ranges, achieves 8 µs max conversion time, and interfaces directly with 8- or 16-bit microprocessor buses. It is used in high-reliability military and aerospace data acquisition systems requiring calibrated, self-contained ADC functionality.
For engineers reviewing the AD774BTD datasheet, AD774BTD pinout, AD774BTD application, or AD774BTD equivalent, key selection considerations include its MIL-qualified ceramic DIP-28 package, ±1 LSB integral linearity over full temperature range, dual-supply analog operation (±12 V/±15 V + 5 V), and compatibility with legacy AD574A-based designs requiring faster throughput and extended thermal performance.
Technical Context
The AD774BTD implements a SAR architecture with internal 10 V reference trimmed to ±1% and 10 ppm/°C drift, enabling direct unipolar/bipolar range selection via external resistor configuration at BIP OFF, 10VIN, and 20VIN pins. Its control logic supports both full-control mode (CS/CE/R/C coordinated) and standalone mode (R/C edge-triggered).
Conversion timing is deterministic: 8 µs maximum for 12-bit cycles, with status flag (STS) synchronized to completion. Output data is left-justified and configurable as one 12-bit word or two 8-bit bytes via 12/8 and A0 pins, buffering into microprocessor busses without external latches.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 4096 discrete codes over full-scale range |
| Conversion Time (max) | 8 µs - enables ≥125 kSPS sustained sampling in burst mode |
| Integral Linearity Error | ±1 LSB - guarantees monotonicity and ≤1-code deviation across –55°C to +125°C |
| Input Ranges | 0 V–10 V, 0 V–20 V, ±5 V, ±10 V - selectable via external resistor network, no reconfiguration IC needed |
| Reference Voltage | 10.00 V ±1% - internally trimmed, supplies up to 2.0 mA externally while maintaining accuracy during conversion |
| Supply Voltages | +5 V (VLOGIC), +12 V/+15 V (VCC), –12 V/–15 V (VEE) - supports ruggedized analog front-end design with independent digital/analog grounds |
| Operating Temperature | –55°C to +125°C - qualified per MIL-STD-883 for extended-environment deployment |
Pinout & Package
AD774BTD is housed in a 28-lead hermetically sealed ceramic DIP (package option D-28), rated for high-reliability military and aerospace applications. Pin assignments follow industry-standard AD574A layout for drop-in replacement in legacy systems.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VLOGIC (Pin 1) | Digital power supply input | Supplies +5 V logic core; decoupling to DGND (Pin 15) required for noise immunity |
| 12/8 (Pin 2) | Digital input | Selects 12-bit word (HIGH) or two 8-bit bytes (LOW); determines DB11–DB0 byte alignment |
| CS (Pin 3) | Digital input | Active-low chip select; must be asserted before CE for valid bus cycle initiation |
| A0 (Pin 4) | Digital input | Controls conversion length (LOW = 12-bit, HIGH = 8-bit) and data byte enable during read |
| R/C (Pin 5) | Digital input | Read/Convert command: LOW = start conversion, HIGH = read data; edge-sensitive in standalone mode |
| CE (Pin 6) | Digital input | Active-high chip enable; initiates conversion or read when CS is active and timing constraints met |
| VCC (Pin 7) | Analog power supply input | +12 V or +15 V analog rail; requires local decoupling to AGND (Pin 9) |
| REF OUT (Pin 8) | Analog output | 10 V reference source; drives external bipolar offset network and calibration loads up to 2.0 mA |
| AGND (Pin 9) | Analog ground | Common return for analog inputs, reference, and VCC/VEE; must be isolated from DGND except at single point |
| REF IN (Pin 10) | Analog input | Reference feedback node; connected via 50 Ω resistor to REF OUT for internal scaling stability |
| VEE (Pin 11) | Analog power supply input | –12 V or –15 V analog rail; decoupled directly to AGND to minimize ground bounce |
| BIP OFF (Pin 12) | Analog input | Bipolar offset adjustment node; tied to REF OUT (±5 V mode) or AGND (0–10 V mode) to configure input range |
| 10 VIN (Pin 13) | Analog input | 0 V–10 V or ±5 V input channel; 5 kΩ nominal impedance; unused in 20 V span mode |
| 20 VIN (Pin 14) | Analog input | 0 V–20 V or ±10 V input channel; 10 kΩ nominal impedance; unused in 10 V span mode |
| DGND (Pin 15) | Digital ground | Return for VLOGIC and digital I/O; separated from AGND to prevent digital noise coupling into analog path |
| DB0–DB3 (Pins 16–19) | Digital output | LSB nibble; enabled only when A0 = HIGH during read; tristated otherwise |
| DB4–DB7 (Pins 20–23) | Digital output | Middle nibble; outputs valid data when A0 = LOW (12-bit mode) or zero-padded when A0 = HIGH (8-bit mode) |
| DB8–DB11 (Pins 24–27) | Digital output | MSB nibble; always active during read; provides upper 4 bits in all configurations |
| STS (Pin 28) | Digital output | Status flag: HIGH during conversion, LOW when result ready; used for polling or interrupt-driven data capture |
Key Features
| Feature | Design Value |
|---|---|
| On-chip 10 V reference | Trimmed to ±1% initial accuracy and 10 ppm/°C drift - eliminates external reference IC and reduces board area/cost |
| Four calibrated input ranges | Hardware-selectable 0 V–10 V, 0 V–20 V, ±5 V, ±10 V - no firmware reconfiguration or external gain switching required |
| Three-state output buffers | Direct 8-/16-bit bus interface with byte/word formatting - removes need for external bus transceivers or latches |
| Industry-standard AD574A pinout | Drop-in replacement for legacy systems - preserves PCB layout, firmware, and test infrastructure |
| MIL-STD-883 qualified | Screened for –55°C to +125°C operation with burn-in and hermetic sealing - meets aerospace and defense reliability requirements |
Applications
| Avionics Sensor Interface | Tactical Vehicle Data Acquisition |
|---|---|
|
Use Scenario: Converting analog outputs from pressure, temperature, and inertial sensors in flight control computers under extreme thermal cycling. IC Role / Device Role / Timing Role: Primary 12-bit ADC capturing sensor data at ≥100 kSPS with guaranteed monotonicity and minimal calibration drift. Use Value: Eliminates external reference and clock components, reducing SWaP-C while maintaining ±1 LSB linearity across –55°C to +125°C. |
Use Scenario: Digitizing engine monitoring signals (oil pressure, coolant temp, RPM) in armored ground vehicles exposed to shock, vibration, and wide ambient swings. IC Role / Device Role / Timing Role: Ruggedized ADC with hermetic DIP packaging and MIL-qualified screening, interfacing directly to vehicle CAN bus controllers via microprocessor bus. Use Value: Enables single-chip signal chain from sensor to microcontroller, avoiding external trimming and supporting field recalibration via BIP OFF and REF IN nodes. |
| Missile Guidance Telemetry | Spacecraft Power Monitoring |
|
Use Scenario: High-fidelity digitization of seeker head analog telemetry and actuator feedback in guided munitions with tight size, weight, and power constraints. IC Role / Device Role / Timing Role: Low-latency 8 µs conversion ADC providing deterministic timing for closed-loop guidance algorithms. Use Value: On-chip clock and reference ensure timing integrity without external oscillators, critical for real-time control in radiation-tolerant but non-rad-hard platforms. |
Use Scenario: Monitoring solar array voltage, battery charge/discharge current, and bus regulation in low-earth orbit satellites with limited thermal management. IC Role / Device Role / Timing Role: Radiation-bonded, hermetically sealed ADC operating reliably at –55°C (eclipse) and +125°C (sunlight exposure) without derating. Use Value: Internal laser-trimmed resistors maintain ±1 LSB linearity across orbital thermal extremes, eliminating periodic recalibration and extending mission life. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD781TQ | 12-bit, 10 µs conversion, ±1 LSB INL, SOIC-28, –40°C to +85°C | Lacks internal reference and clock; requires external 10 V ref and timing source; lower temperature grade | Choose AD774BTD when full integration, extended temperature, or MIL qualification is mandatory. |
| AD1674TQ | 12-bit, 10 µs sampling ADC, includes sample-and-hold, same pinout, –40°C to +85°C | Integrated S/H enables true simultaneous sampling; higher power (400 mW); no MIL-qualified variant | Choose AD774BTD when system already includes external S/H or when ultra-low power and hermetic packaging outweigh S/H benefit. |
Compared with AD781TQ and AD1674TQ, AD774BTD uniquely combines on-chip reference, clock, MIL-STD-883 screening, and –55°C to +125°C operation in a single ceramic DIP-making it the only option for high-reliability embedded systems where component count, thermal margin, and qualification compliance are non-negotiable.
Availability
AD774BTD is available at Aetrix Electronics and suitable for avionics sensor interface, tactical vehicle data acquisition, and missile guidance telemetry requiring stable component supply, long-term obsolescence management, and traceable MIL-grade sourcing.
Supply support for AD774BTD 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, serving precision instrumentation, aerospace, and industrial markets since 1965.
The AD774BTD belongs to Analog Devices' legacy high-reliability data converter family designed specifically for military, aerospace, and harsh-environment applications demanding full integration, extended temperature operation, and MIL-qualified assurance.
FAQ
What is the maximum conversion rate supported by the AD774BTD?
The AD774BTD achieves a maximum conversion time of 8 µs per 12-bit sample, enabling a theoretical sustained throughput of 125 kSPS. This assumes optimal bus timing, minimal inter-conversion overhead, and use of the standalone mode (R/C edge-triggered). Real-world system rates may be lower due to microprocessor bus arbitration, status polling latency, and data read cycles - but the AD774BTD's deterministic timing ensures predictable worst-case performance in hard real-time systems.
Does the AD774BTD require external calibration components?
The AD774BTD includes factory-laser-trimmed thin-film resistors for offset, full-scale, and bipolar scaling, so no external trim components are required for basic operation. However, optional external 50 Ω resistors at REF IN and BIP OFF allow fine calibration: a 50 Ω resistor between REF OUT and REF IN sets full-scale gain, while connecting BIP OFF to REF OUT (for bipolar) or AGND (for unipolar) configures input range. These are passive, fixed-value elements - not active trim circuits.
Can the AD774BTD operate with only +5 V and ground supplies?
No. The AD774BTD requires three separate supply rails: +5 V (VLOGIC, Pin 1), +12 V or +15 V (VCC, Pin 7), and –12 V or –15 V (VEE, Pin 11). The analog section uses dual supplies to support bipolar input ranges (±5 V, ±10 V) and maintain linearity across full scale. Operating with only +5 V and ground will prevent proper comparator biasing, DAC operation, and reference stability - resulting in invalid or missing codes. Decoupling each rail to its respective ground (AGND or DGND) is mandatory.
How does the AD774BTD handle input signals exceeding its specified voltage ranges?
The AD774BTD specifies absolute maximum ratings of ±24 V on 20VIN and ±16.5 V on VCC/VEE, allowing limited overvoltage tolerance. However, its functional input ranges remain strictly 0 V–10 V, 0 V–20 V, ±5 V, or ±10 V - determined by resistor configuration at BIP OFF, 10VIN, and 20VIN. Inputs beyond these ranges will saturate the internal comparator and produce clipped digital output (all 0s or all 1s), with no guarantee of recovery or damage-free operation beyond absolute max limits. External clamping or attenuation is required for overrange protection.
Is the AD774BTD pin-compatible with the AD574A, and what are the key improvements?
Yes - the AD774BTD maintains identical pinout, signal definitions, and package footprint (ceramic DIP-28) as the AD574A, enabling drop-in replacement. Key improvements include 8 µs max conversion time (vs. 25 µs for AD574A), integrated 10 V reference (eliminating external ref IC), on-chip clock generator (removing external crystal), lower power consumption (375 mW vs. ~500 mW), and extended temperature range (–55°C to +125°C vs. –40°C to +85°C for AD574A T-grade). All improvements retain full software and hardware compatibility.
AD774BTD 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):
- -
- Number of Inputs:
- 2
- Input Type:
- Single Ended
- Data Interface:
- Parallel
- Configuration:
- ADC
- Ratio - S/H:ADC:
- -
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- Internal
- Voltage - Supply, Analog:
- ±11.4V ~ 16.5V
- Voltage - Supply, Digital:
- 5V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 28-CDIP
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
AD774BTD FAQ
1.How can I place an order for AD774BTD through Aetrix?
Please submit a Request for Quotation (RFQ) for AD774BTD 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 AD774BTD reliable?
The price and inventory of AD774BTD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD774BTD is usually 5 days.
3.What payment methods are accepted for AD774BTD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD774BTD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD774BTD?
AD774BTD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD774BTD 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 AD774BTD?
For technical support, including AD774BTD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD774BTD requirements.
6.How does Aetrix verify that AD774BTD is sourced from the original manufacturer or authorized distributors?
All AD774BTD 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 AD774BTD meets industry standards.
7.What is the process for return or replacement of AD774BTD?
All AD774BTD units undergo pre-shipment inspection (PSI). If there is an issue with AD774BTD, 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 AD774BTD part is unused and in its original packaging.
Return procedure for AD774BTD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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