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Analog Devices Inc. AD694BRZ
- Part No.:
- AD694BRZ
- Manufacturer:
- Analog Devices Inc.
- Category:
- Sensor and Detector Interfaces
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AD694BRZ.pdf
- Description:
- IC TRANSMITTER 4-20MA 16-SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,511
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Product details
Overview
AD694BRZ from Analog Devices is a monolithic 4–20 mA current transmitter IC designed for industrial process control signal conditioning. It accepts precalibrated 0 V to 2 V or 0 V to 10 V single-ended voltage inputs, integrates a precision 2.000 V or 10.000 V reference, delivers 4–20 mA output with ±0.001% of span/°C temperature drift, and operates from 4.5 V to 36 V supply - enabling direct interface to valves, actuators, and sensor transmitters in factory automation systems.
For engineers reviewing the AD694BRZ datasheet, AD694BRZ pinout, AD694BRZ application, or AD694BRZ equivalent, key selection considerations include its programmable input span, open-loop alarm (Pin 10), 4 mA on/off control (Pin 9), compliance to within 2 V of VS, and support for external pass transistor operation to extend thermal range - all critical for loop-powered field instrumentation design.
Technical Context
The AD694BRZ implements a three-stage architecture: a PNP-input buffer amplifier (Pin 2/3/1) with rail-to-rail common-mode range down to −0.3 V, a voltage-to-current (V/I) converter generating 0–16 mA signal current via internal current mirror and Darlington output stage, and a laser-trimmed voltage reference (2 V or 10 V selectable via Pin 7/8) feeding a 4 mA offset generator. Its unique output stage allows IOUT (Pin 11) to drive loads up to 36 V below VS - supporting dual-supply DAC interfacing without level-shifting.
Pin-strapping configures core functions: Pin 4 shorted to COM selects 2 V full-scale input; Pin 7 shorted to Pin 8 enables 2 V reference; Pin 9 ≥3.0 V disables 4 mA offset for 0–20 mA mode; and Pin 14 accepts external capacitor for bandwidth limiting. The alarm circuit (Pin 10) asserts low on open-loop or output noncompliance (IOUT > VS − 2 V), while Pin 6 provides ±2.5 mV trim range for 4 mA zero adjustment.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Range | 0 V to 2 V or 0 V to 10 V - precalibrated spans selected by pin strap, no external resistor calibration required |
| Output Current | 4–20 mA - specified performance range with ±5 µA max 4 mA offset error over −40°C to +85°C |
| Reference Accuracy | 2.000 V ±0.004 V or 10.000 V ±0.020 V - laser-trimmed, 45 ppm/°C max drift over temperature |
| Supply Range | 4.5 V to 36 V - supports single-supply operation down to 4.5 V when using 2 V input/reference |
| Output Compliance | VS − 2 V minimum - enables driving 525 Ω load at 12.5 V supply; extends 36 V below VS in dual-supply mode |
| Nonlinearity | ±0.001% of span - ensures high-fidelity analog transmission for precision pressure/temperature transmitters |
| Alarm Function | Open-collector output (Pin 10) - sinks 20 mA when IOUT open or exceeds VS − 2 V, compatible with PLC input modules |
Pinout & Package
AD694BRZ is housed in a 16-pin plastic SOIC package (body width 7.5 mm, lead pitch 1.27 mm), rated for −40°C to +85°C operation. Pin layout follows standard SOIC-16 footprint with exposed pad not electrically connected.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (FB) | Buffer amplifier output | Class A follower output; drives −SIG (Pin 2); range: 1 mV to VS − 2.5 V; max 5 kΩ source load |
| 2 (−SIG) | Buffer inverting input | Connected to FB for unity-gain configuration; forms V/I converter input node with +SIG |
| 3 (+SIG) | Buffer noninverting input | Accepts 0–2 V or 0–10 V input; common-mode range extends to −0.3 V below COM |
| 4 (2V FS) | 2 V full-scale select | Short to COM (Pin 5) to configure 0–2 V input span; open for 0–10 V span |
| 5 (COM) | Ground reference | Substrate and circuit common; all other pins referenced to this node |
| 6 (4mA ADJ) | Offset current trim | Adjusts 4 mA zero from 2.0 mA to 4.8 mA via external potentiometer |
| 7 (10V FORCE) | Reference force node | Short to Pin 8 for 2 V reference; left open for 10 V reference (requires VS > 12.5 V) |
| 8 (2V SENSE) | Reference sense node | Short to Pin 7 for 2 V reference; carries 100 µA bias current - avoid long traces |
| 9 (4mA ON/OFF) | Offset enable/disable | ≤0.8 V enables 4 mA offset; ≥3.0 V disables offset for 0–20 mA operation |
| 10 (ALARM) | Open-collector fault indicator | Sinks 20 mA when IOUT open or exceeds VS − 2 V; requires external pull-up |
| 11 (IOUT) | Current output terminal | Drives 4–20 mA loop; compliance extends to VS − 2 V (single supply) or 36 V below VS (dual supply) |
| 12 (BOOST) | 2 V reference boost control | Connects to NPN base to increase 2 V reference drive capability beyond 5 mA |
| 13 (VS) | Positive supply input | Accepts 4.5 V to 36 V; decoupling cap (0.1 µF) required from VS to COM |
| 14 (BW ADJUST) | Bandwidth filter node | External capacitor to VS sets dominant pole - reduces noise susceptibility in EMI-prone environments |
| 15, 16 (VOS ADJ) | Input offset trim | Adjusts buffer amplifier input offset voltage; used only if high-precision DC accuracy required |
Key Features
| Feature | Design Value |
|---|---|
| Precalibrated input spans | 0 V to 2 V and 0 V to 10 V - selected by pin strap, eliminating external gain-setting resistors and calibration labor |
| Programmable 4–20 mA / 0–20 mA output | Pin 9 TTL-compatible control - enables remote loop shutdown or valve "jiggle" without hardware change |
| Wide output compliance | Drives loads to within 2 V of VS (single supply) or 36 V below VS (dual supply) - simplifies interface to bipolar DACs |
| Laser-trimmed voltage reference | 2.000 V or 10.000 V output with ±0.004 V accuracy and 45 ppm/°C drift - eliminates need for external reference IC |
| Integrated open-loop alarm | Active-low open-collector output (Pin 10) - directly interfaces to PLC digital inputs for loop integrity monitoring |
| External pass transistor support | Monitored output (Pin 11) drives NPN base - offloads power dissipation to extend operating temperature range |
Applications
| Pressure Transmitter Interface | Temperature Sensor Conditioning |
|---|---|
|
Use Scenario: Converting bridge output from piezoresistive pressure sensor (0–100 mV) into 4–20 mA loop signal for PLC acquisition over 1000 m cable. IC Role / Device Role / Timing Role: AD694BRZ acts as precision voltage-to-current converter with integrated reference and buffer amplifier scaling. Use Value: Eliminates external op-amp, reference, and current-sense resistor - reduces BOM count and improves long-term stability vs. discrete solutions. |
Use Scenario: Conditioning output of RTD-based temperature sensor (via 3-wire connection) into noise-immune 4–20 mA signal for HVAC control panel. IC Role / Device Role / Timing Role: AD694BRZ serves as loop-powered transmitter with 0–10 V input range and 2 V reference for excitation. Use Value: Built-in 2 V reference powers RTD bridge; open-loop alarm detects broken sensor wires - enhancing system diagnostics. |
| Valve Actuator Control | Factory Automation I/O Module |
|
Use Scenario: Driving pneumatic valve positioner requiring precise 4–20 mA setpoint signal from microcontroller DAC output. IC Role / Device Role / Timing Role: AD694BRZ functions as DAC interface and current driver with 0–2 V input range and 4 mA zero trim. Use Value: Pin 9 "jiggle" function enables momentary 0 mA output to unstick valves - reducing mechanical maintenance frequency. |
Use Scenario: Integrating into modular I/O rack where each channel must support both 4–20 mA input and output with diagnostic capability. IC Role / Device Role / Timing Role: AD694BRZ operates as bidirectional current transmitter with alarm feedback for loop health monitoring. Use Value: Alarm output (Pin 10) feeds back to FPGA host for real-time loop status - enabling predictive maintenance alerts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 4–20 mA transmitter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| XTR115UA | 2-wire, loop-powered design; requires external 4.096 V reference; no integrated 2 V/10 V reference | Optimized for 2-wire sensor transmitters with <1.5 mA quiescent current; lacks pin-strappable input spans | Choose XTR115UA when ultra-low power and 2-wire topology are mandatory; AD694BRZ preferred for 3-wire, wide supply, and precalibrated spans |
| MAX16992ATP+ | Automotive-grade AEC-Q100; integrated watchdog timer; no programmable 0–20 mA mode | Designed for automotive body electronics; includes fault reporting via SPI; higher cost and qualification overhead | Choose MAX16992ATP+ for automotive safety-critical systems; AD694BRZ remains optimal for industrial process control with simpler integration |
Compared with XTR115UA and MAX16992ATP+, the AD694BRZ offers superior flexibility in input span selection, integrated reference options, and dual-supply compatibility - making it the most suitable choice for general-purpose industrial 4–20 mA transmitter designs where board space and calibration effort are constrained.
Availability
AD694BRZ is available at Aetrix Electronics and suitable for industrial process control, factory automation, and sensor transmitter applications requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for AD694BRZ 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, communications, and automotive markets since 1965.
The AD694BRZ belongs to Analog Devices' precision signal conditioning product line, engineered specifically for robust, calibration-free 4–20 mA current loop transmission in harsh industrial environments.
FAQ
What input voltage ranges does the AD694BRZ support without external resistors?
The AD694BRZ supports two precalibrated input voltage ranges without external components: 0 V to 2 V and 0 V to 10 V. These are selected by pin strapping - shorting Pin 4 (2V FS) to Pin 5 (COM) configures the 0–2 V range, while leaving Pin 4 open enables the 0–10 V range. Both spans are laser-trimmed at wafer test, ensuring ±0.005% of span nonlinearity and eliminating manual calibration. The AD694BRZ does not require external gain-setting resistors for these configurations.
Can the AD694BRZ operate from a 5 V supply?
Yes, the AD694BRZ can operate from a 5 V supply when configured for the 0–2 V input range and 2 V reference output. Per the datasheet, the minimum supply voltage is 4.5 V under these conditions. At 5 V, the output compliance reaches VS − 2 V = 3 V, supporting up to 150 Ω load at 20 mA. Operation with 0–10 V input or 10 V reference requires ≥12.5 V supply. The AD694BRZ's wide 4.5 V to 36 V range makes it suitable for battery-backed or low-voltage industrial systems.
How does the alarm function work on the AD694BRZ?
The AD694BRZ alarm (Pin 10) is an open-collector output that pulls low when either the 4–20 mA loop opens or the output voltage at IOUT (Pin 11) exceeds VS − 2 V. It sinks up to 20 mA and requires an external pull-up resistor (typically 10 kΩ to VS). This feature enables direct connection to PLC digital inputs for real-time loop integrity monitoring. The alarm circuit is internally tied to the V/I converter's compliance detection and does not require additional external circuitry - a key differentiator of the AD694BRZ versus discrete transmitter designs.
Is the AD694BRZ pin-compatible with earlier AD694 variants like AD694JN?
No, the AD694BRZ is not pin-compatible with the AD694JN. While both share identical pin numbering and functional definitions per the datasheet, the AD694JN uses a 16-pin plastic DIP package (0°C to +70°C), whereas the AD694BRZ uses a 16-pin SOIC package (−40°C to +85°C) with different mechanical dimensions and thermal characteristics. PCB footprints, reflow profiles, and thermal management requirements differ significantly. Migration from AD694JN to AD694BRZ requires board layout revision - the AD694BRZ is a drop-in replacement only within the BR/BRZ/BQ family.
Does the AD694BRZ support 0–20 mA output, and how is it enabled?
Yes, the AD694BRZ supports 0–20 mA output by disabling the 4 mA offset current. This is accomplished by driving Pin 9 (4mA ON/OFF) to ≥3.0 V - typically via connection to the 10 V reference, VS, or a TTL logic high. When disabled, the transfer function becomes 0–20 mA for the same input span, effectively increasing full-scale input to 2.5 V (for original 2 V span) or 12.5 V (for original 10 V span). The AD694BRZ retains all other specifications including alarm functionality and compliance range in 0–20 mA mode.
AD694BRZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Series:
- -
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Current Transmitter
- Input Type:
- Voltage
- Output Type:
- Voltage
- Current - Supply:
- 23 mA
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
AD694BRZ FAQ
1.How can I place an order for AD694BRZ through Aetrix?
Please submit a Request for Quotation (RFQ) for AD694BRZ 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 AD694BRZ reliable?
The price and inventory of AD694BRZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD694BRZ is usually 5 days.
3.What payment methods are accepted for AD694BRZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD694BRZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD694BRZ?
AD694BRZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD694BRZ 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 AD694BRZ?
For technical support, including AD694BRZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD694BRZ requirements.
6.How does Aetrix verify that AD694BRZ is sourced from the original manufacturer or authorized distributors?
All AD694BRZ 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 AD694BRZ meets industry standards.
7.What is the process for return or replacement of AD694BRZ?
All AD694BRZ units undergo pre-shipment inspection (PSI). If there is an issue with AD694BRZ, 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 AD694BRZ part is unused and in its original packaging.
Return procedure for AD694BRZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AD694BRZ Tags
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