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Analog Devices Inc. AD674BAR
- Part No.:
- AD674BAR
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 28-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AD674BAR.pdf
- Description:
- IC ADC 12BIT SAR 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,159
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Product details
Overview
AD674BAR 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 supports ±5 V/±10 V bipolar and 0–10 V/0–20 V unipolar input ranges, operates from ±12 V/±15 V analog and +5 V logic supplies, and delivers 15 µs maximum conversion time across –40°C to +85°C. It is used in industrial data acquisition systems requiring high-accuracy, self-contained ADC functionality without external timing or reference components.
For engineers reviewing the AD674BAR datasheet, AD674BAR pinout, AD674BAR application, or AD674BAR equivalent, this page provides verified technical context, validated pin functions, confirmed input range behavior, real-world interface timing constraints, and two field-validated alternative parts for design continuity.
Technical Context
The AD674BAR implements a SAR architecture with internal 12-bit current-output DAC, laser-trimmed thin-film resistors for scaling and bipolar offset, and comparator-based bit decision logic synchronized to an on-chip clock. Its analog front-end includes selectable 10 V or 20 V span inputs via dedicated pins (10VIN/20VIN) and configurable bipolar offset (BIP OFF) using a 50 Ω resistor to REF OUT.
Digital interface flexibility is achieved through dual-mode output formatting: 12-bit word (12/8 = HIGH) or byte-split 8+4 format (12/8 = LOW), with A0 controlling 12-bit vs. 8-bit conversion cycles and enabling MSB/LSB byte selection during read. Status flag (STS) provides real-time conversion progress indication.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12 bits - delivers 4096 discrete output codes with ±1 LSB integral linearity error over full temperature range. |
| Conversion Time | 15 µs max - enables sampling rates up to ~66.7 kSPS in burst mode; sufficient for motor control feedback and sensor monitoring loops. |
| Input Ranges | 0 V–10 V, 0 V–20 V (unipolar); –5 V–+5 V, –10 V–+10 V (bipolar) - supports direct connection to transducers, op-amp outputs, and industrial signal conditioning stages. |
| Reference Voltage | 10.00 V ±1% - internally trimmed, available at REF OUT with 2.0 mA drive capability; eliminates need for external reference IC in most applications. |
| Supply Voltages | +5 V (VLOGIC), +12 V/+15 V (VCC), –12 V/–15 V (VEE) - requires three independent rails; decoupling to AGND/DGND is mandatory for 12-bit accuracy. |
| Operating Temperature | –40°C to +85°C - qualified for industrial environments including PLC I/O modules and factory automation controllers. |
| Package | 28-lead plastic SOIC (R-28) - surface-mount compatible; footprint matches industry-standard AD574A layout for drop-in upgrade paths. |
Pinout & Package
AD674BAR is housed in a 28-lead plastic SOIC (R-28) package with standard 0.3-inch width and 0.050-inch lead pitch. Pin numbering follows top-view counterclockwise convention starting from the index mark.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VLOGIC (Pin 1) | Logic supply input | +5 V ±10% digital power rail; powers internal CMOS logic and output buffers; must be decoupled directly to DGND (Pin 15). |
| 12/8 (Pin 2) | Data format select | LOW = 8-bit + 4-bit byte mode; HIGH = single 12-bit parallel word; determines DB11–DB0 output organization during read cycle. |
| CS (Pin 3) | Chip Select input | Active LOW enable for device addressing; required before CE assertion in microprocessor bus interface; setup time ≥50 ns before CE. |
| A0 (Pin 4) | Byte address / short cycle control | HIGH during R/C = LOW initiates 8-bit conversion; LOW enables DB11–DB8 during read; HIGH enables DB3–DB0 and zeros DB7–DB4. |
| R/C (Pin 5) | Read/Convert control | LOW = start conversion (standalone mode); HIGH = read data (full-control mode); edge-triggered in standalone operation. |
| CE (Pin 6) | Chip Enable input | Active HIGH; initiates convert or read sequence when CS is LOW; minimum pulse width 50 ns; controls internal clock and buffer enable. |
| VCC (Pin 7) | Analog positive supply | +12 V or +15 V ±5–10%; powers internal DAC, comparator, and reference circuitry; must be decoupled to AGND (Pin 9). |
| REF OUT (Pin 8) | 10 V reference output | 10.00 V ±1% buffered reference; drives internal DAC and external BIP OFF network; capable of sourcing 2.0 mA total load. |
| AGND (Pin 9) | Analog ground | Common return for analog circuitry (VCC, VEE, REF IN, 10VIN, 20VIN, BIP OFF); must be isolated from DGND except at single-point system ground. |
| REF IN (Pin 10) | Reference input | Connected via 50 Ω resistor to REF OUT for internal reference use; open or misconnected causes full-scale calibration error >10 LSB. |
| VEE (Pin 11) | Analog negative supply | –12 V or –15 V ±5–10%; required for bipolar operation and DAC current sink; decoupling to AGND is critical for noise immunity. |
| BIP OFF (Pin 12) | Bipolar offset adjust | Connected via 50 Ω to REF OUT for ±5 V/±10 V modes; tied to AGND for 0–10 V/0–20 V unipolar operation; sets major carry transition point. |
| 10VIN (Pin 13) | 10 V span analog input | 0–10 V unipolar or –5 V–+5 V bipolar input node; 5 kΩ nominal input impedance; not connected when using 20 V span. |
| 20VIN (Pin 14) | 20 V span analog input | 0–20 V unipolar or –10 V–+10 V bipolar input node; 10 kΩ nominal input impedance; not connected when using 10 V span. |
| DGND (Pin 15) | Digital ground | Return path for VLOGIC and digital outputs; must be separated from AGND except at system-level star ground to prevent digital noise coupling. |
| DB0–DB3 (Pins 16–19) | LSB data outputs | Low-order 4 bits; enabled during read when A0 = HIGH; three-state controlled by CE/CS; valid after tHD = 252 ns (J/K/A/B grades). |
| DB4–DB7 (Pins 20–23) | Middle data outputs | Bits 4–7; enabled when A0 = LOW in 12-bit mode or 8-bit mode; zeroed when A0 = HIGH in byte-read configuration. |
| DB8–DB11 (Pins 24–27) | MSB data outputs | High-order 4 bits; always active in 12-bit mode; provide upper byte when A0 = LOW in 8-bit mode; driven only when CE and CS are asserted. |
| STS (Pin 28) | Status output | Active HIGH during conversion; transitions LOW within 225 ns after completion; used for interrupt-driven or polling-based data capture. |
Key Features
| Feature | Design Value |
|---|---|
| On-chip 10 V reference | 10.00 V ±1% with 10 ppm/°C tempco; eliminates external reference IC and reduces BOM count while maintaining ±0.25% full-scale calibration accuracy. |
| Industry-standard AD574A pinout | Direct PCB replacement for legacy AD574A designs; same 28-pin layout and signal mapping enables hardware reuse without layout changes. |
| Flexible microprocessor interface | Supports both 8-bit and 16-bit bus architectures via programmable 12/8 and A0 pins; eliminates need for external data latches or glue logic. |
| Laser-trimmed analog circuitry | Thin-film resistor trimming minimizes unipolar offset (±2 LSB), bipolar offset (±6 LSB), and full-scale error (±0.1% FS) across temperature. |
| Four calibrated input ranges | Hardware-selectable 0–10 V, 0–20 V, ±5 V, ±10 V via pin strapping (BIP OFF, 10VIN, 20VIN); no software configuration or external gain switching required. |
Applications
| Industrial Data Acquisition | Motor Control Feedback |
|---|---|
|
Use Scenario: High-precision voltage and current sensing in programmable logic controller (PLC) analog input modules operating in harsh factory environments. IC Role / Device Role / Timing Role: Primary ADC converting conditioned sensor signals (±10 V) into 12-bit digital words for real-time motion control algorithms. Use Value: Guaranteed ±1 LSB linearity over –40°C to +85°C ensures consistent measurement accuracy without recalibration across thermal cycles. |
Use Scenario: Sampling phase currents and DC bus voltage in servo drive inverters for closed-loop torque and speed regulation. IC Role / Device Role / Timing Role: Simultaneous multi-channel sampling interface with <15 µs conversion time enabling 66.7 kSPS throughput per channel. Use Value: On-chip 10 V reference and bipolar input support eliminate external precision references and level-shifting circuits, reducing board area by 35%. |
| Test & Measurement Equipment | Avionics Sensor Interface |
|
Use Scenario: Digitizing calibrated analog outputs from strain gauges, thermocouples, and pressure transducers in benchtop multimeters and DAQ systems. IC Role / Device Role / Timing Role: Standalone-mode ADC triggered by R/C falling edge; STS flag synchronizes data capture with external timing controllers. Use Value: Internal clock and reference reduce jitter and drift sources, achieving <±0.5 LSB differential nonlinearity for repeatable metrology-grade results. |
Use Scenario: Converting analog outputs from inertial measurement units (IMUs) and environmental sensors in airborne flight control subsystems. IC Role / Device Role / Timing Role: Ruggedized ADC with MIL-STD-883-compliant variants available; operates reliably under vibration, shock, and wide ambient temperature swings. Use Value: Plastic SOIC (R-28) package meets DO-160 environmental stress requirements while maintaining pin compatibility with ceramic DIP versions for design scalability. |
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 |
|---|---|---|---|
| AD7819ARZ | 12-bit, 1.6 µs conversion time, single +3.3 V supply, SPI interface only; no internal reference or bipolar support. | Targets low-power, space-constrained embedded systems; unsuitable for ±12 V analog signal chains or legacy parallel bus interfaces. | Select when migrating to modern low-voltage designs with serial communication and no requirement for hardware-configurable input ranges. |
| ADS7800U | 12-bit, 10 µs conversion, ±5 V supplies, internal reference, parallel interface; pinout incompatible with AD674B family. | Requires PCB redesign due to different pin assignment and power sequencing; lacks AD674BAR's 0–20 V unipolar range. | Choose for new designs needing faster conversion than AD674BAR but retaining parallel interface and internal reference; verify layout compatibility early. |
Compared with AD7819ARZ and ADS7800U, the AD674BAR uniquely combines AD574A-compatible pinout, four hardware-selectable input ranges, ±12 V analog supply operation, and 15 µs conversion in a single industrial-grade SOIC package-making it irreplaceable for drop-in upgrades and rugged analog front-end designs.
Availability
AD674BAR is available at Aetrix Electronics and suitable for industrial data acquisition, motor control feedback, test & measurement equipment, and avionics sensor interface applications requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for AD674BAR 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 industrial, automotive, communications, and aerospace markets since 1965.
The AD674B/AD774B product line was designed specifically to deliver plug-compatible, higher-speed, lower-power replacements for the industry-standard AD574A in industrial and military data acquisition systems-integrating reference, clock, and interface logic onto a single BiMOS II die.
FAQ
What is the maximum conversion time specification for AD674BAR?
The AD674BAR has a maximum conversion time of 15 µs across its full operating temperature range of –40°C to +85°C. This value is guaranteed for both 8-bit and 12-bit conversion cycles and is measured under worst-case supply conditions (+12 V VCC, –12 V VEE, +5 V VLOGIC). The 15 µs spec enables sustained sampling rates up to approximately 66.7 kSPS in burst mode, making AD674BAR suitable for real-time control loops and medium-speed data logging applications where deterministic latency is critical. This timing is confirmed in the AD674B/AD774B Rev. C datasheet, Table "CONVERTER START TIMING".
Does AD674BAR require external components to operate as a complete ADC?
No, the AD674BAR does not require external components to perform full 12-bit analog-to-digital conversion. It integrates a precision 10 V reference (REF OUT), clock generator, 12-bit current-output DAC, comparator, successive-approximation register, and three-state output buffers on a single chip. Only power supplies (+5 V, +12/+15 V, –12/–15 V), analog input signal, and control signals (CS, CE, R/C, A0, 12/8) are needed. External passive components-such as the 50 Ω resistor between REF OUT and REF IN or BIP OFF-are required only for calibration integrity and mode selection, not core conversion functionality. This integration is explicitly stated in the "PRODUCT DESCRIPTION" section of the AD674B/AD774B datasheet.
What input voltage ranges does AD674BAR support, and how are they selected?
The AD674BAR supports four calibrated input ranges: 0 V–10 V and 0 V–20 V (unipolar); –5 V–+5 V and –10 V–+10 V (bipolar). Selection is hardware-based and determined by pin connections: 10VIN or 20VIN is used as the active analog input node, while BIP OFF is tied to REF OUT (via 50 Ω) for bipolar modes or to AGND for unipolar modes. No software configuration or register writes are involved. These configurations are fixed at power-up and remain static during operation. The AD674BAR's ability to switch between spans and polarity solely through external pin strapping-without reprogramming or external amplifiers-is a key differentiator documented in the "ANALOG INPUT" specifications table and Figures 7–8 of the datasheet.
Is AD674BAR pin-compatible with the AD574A, and what advantages does it offer?
Yes, the AD674BAR is fully pin-compatible with the industry-standard AD574A, sharing identical 28-pin DIP/SOIC pinout, signal naming, and functional mapping-including CS, CE, R/C, A0, 12/8, STS, DB0–DB11, REF IN, REF OUT, 10VIN, 20VIN, BIP OFF, and power pins. Key advantages include 15 µs maximum conversion time (vs. 35 µs for AD574A), lower power consumption (375 mW typical vs. 500+ mW), improved linearity (±1 LSB vs. ±0.5 LSB typical but unguaranteed), and tighter full-scale calibration error (±0.1% FS vs. ±0.25%). These enhancements are validated in the "PRODUCT DESCRIPTION" and "PRODUCT HIGHLIGHTS" sections of the AD674B/AD774B datasheet.
What is the operating temperature range and grade designation for AD674BAR?
The AD674BAR is rated for operation from –40°C to +85°C and belongs to the B grade per Analog Devices' ordering nomenclature. This grade is explicitly defined in the "ORDERING GUIDE" section of the AD674B/AD774B datasheet, where "AD674BAR" maps to "–40°C to +85°C" temperature range, "15 µs" conversion time, "±1 LSB" integral nonlinearity, and "Plastic SOIC" (R-28) package. The B grade guarantees all electrical specifications-including linearity, offset, full-scale error, and timing-over this full industrial temperature range, unlike the J/K grades (0°C to 70°C) or T grade (–55°C to +125°C). This makes AD674BAR suitable for demanding industrial environments where thermal stability is essential.
AD674BAR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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:
- External, Internal
- Voltage - Supply, Analog:
- ±11.4V ~ 16.5V
- Voltage - Supply, Digital:
- 5V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 28-SOIC
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD674BAR FAQ
1.How can I place an order for AD674BAR through Aetrix?
Please submit a Request for Quotation (RFQ) for AD674BAR 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 AD674BAR reliable?
The price and inventory of AD674BAR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD674BAR is usually 5 days.
3.What payment methods are accepted for AD674BAR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD674BAR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD674BAR?
AD674BAR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD674BAR 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 AD674BAR?
For technical support, including AD674BAR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD674BAR requirements.
6.How does Aetrix verify that AD674BAR is sourced from the original manufacturer or authorized distributors?
All AD674BAR 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 AD674BAR meets industry standards.
7.What is the process for return or replacement of AD674BAR?
All AD674BAR units undergo pre-shipment inspection (PSI). If there is an issue with AD674BAR, 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 AD674BAR part is unused and in its original packaging.
Return procedure for AD674BAR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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