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Analog Devices Inc. AD595AQ
- Part No.:
- AD595AQ
- Manufacturer:
- Analog Devices Inc.
- Category:
- Thermal Management
- Package:
- 14-CDIP (0.300", 7.62mm)
- Datasheet:
-
AD595AQ.pdf
- Description:
- IC THERMOCOUPLE A W/COMP 14CDIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,870
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Product details
Overview
AD595AQ from Analog Devices is a monolithic thermocouple amplifier with integrated cold junction compensation, designed for Type K (chromel–alumel) thermocouples. It delivers a calibrated 10 mV/°C output voltage, supports single- or dual-supply operation (+5 V to ±15 V), features thermocouple open-circuit alarm detection, and achieves ±3°C calibration accuracy over 0°C to +50°C ambient - used in industrial furnace temperature monitoring, HVAC sensor interfaces, and embedded process control systems.
For engineers reviewing the AD595AQ datasheet, AD595AQ pinout, AD595AQ application, or AD595AQ equivalent, this page provides verified functional identity, confirmed pin roles, real-world setpoint controller and Celsius transducer use cases, and two validated alternative parts with documented technical and application differences.
Technical Context
The AD595AQ implements a dual-differential amplifier architecture: one stage conditions the thermocouple signal while the other applies ice-point compensation voltage proportional to chip temperature. Both stages share matched gain (247.3 for Type K), enabling precise cancellation of reference-junction error. The feedback network (Pin 8 to Pin 9) sets nominal transfer function at 10 mV/°C.
It integrates a current-limited alarm transistor (Pin 12/+ALM and Pin 13/–ALM) that asserts low on thermocouple lead open-circuit, with TTL-compatible output drive. Pin-strappable configuration allows linear amplification mode or switched setpoint controller mode using external voltage applied to FB (Pin 8), without requiring external op-amps or discrete compensation circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Transfer Function | 10 mV/°C - directly converts thermocouple EMF + cold-junction compensation into linear Celsius-scaled voltage output |
| Calibration Accuracy (0°C to +50°C) | ±3°C - guaranteed maximum error at +25°C ambient, specified for Type K thermocouple input |
| Supply Voltage Range | +5 V to ±15 V - enables single-supply 0°C-to-300°C measurement or dual-supply extended range including sub-zero temperatures |
| Quiescent Current (No Load) | 160 µA on +VS, 100 µA on –VS - enables low-power remote sensing with minimal self-heating (<0.065°C in still air) |
| Usable Output Current | ±5 mA - drives standard ADC inputs, analog meters, or comparator thresholds without external buffering |
| Alarm Output Capability | TTL-compatible sink/source - +ALM (Pin 12) pulls low on open thermocouple; –ALM (Pin 13) referenced to V– for grounded-emitter configurations |
| Input Offset Voltage Contribution | 11 µV - laser-trimmed absolute offset added to Type K thermocouple voltage before gain scaling (247.3×) |
Pinout & Package
AD595AQ is housed in a 14-pin, side-brazed ceramic DIP (TO-116 / D-14) package with hermetic sealing for high-reliability industrial environments. Pin layout supports differential thermocouple input, dedicated compensation terminals, alarm outputs, and configurable feedback.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (+IN) | Thermocouple positive input | Differential input terminal for chromel (Type K) thermocouple wire; high-impedance, rejects common-mode noise |
| 2 (+C) | Positive compensation current source | Provides positive TC coefficient current for ice-point network; must not be shorted or loaded below 10 kΩ |
| 3 (+T) | Positive thermocouple compensation output | Outputs Kelvin-proportional voltage; used for recalibration or thermometer mode via COM connection |
| 4 (COM) | Signal/common ground reference | Reference node for thermocouple return, alarm circuit, and internal biasing; ties to system ground or –VS in dual supply |
| 5 (–T) | Negative thermocouple compensation output | Complementary Kelvin-proportional output; used with +T for zero-point adjustment during recalibration |
| 6 (–C) | Negative compensation current sink | Sinks negative TC coefficient current; must not be shorted or loaded below 10 kΩ |
| 7 (V–) | Negative supply rail | Accepts –VS up to –16.5 V; required for sub-zero temperature measurement and extended output swing |
| 8 (FB) | Feedback network input | Connects to Pin 9 (VO) for 10 mV/°C gain; accepts external setpoint voltage for comparator mode |
| 9 (VO) | Voltage output | Low-impedance buffered output delivering 10 mV/°C scaled voltage; capable of ±5 mA drive |
| 10 (COMP) | Compensation amplifier output | Internal node for optional external frequency compensation (e.g., 300 pF cap to VO for low-gain stability) |
| 11 (V+) | Positive supply rail | Accepts +VS from +5 V to +15 V; powers all internal circuitry including alarm transistor |
| 12 (+ALM) | Alarm active-high collector | Open-collector TTL output; pulled high externally, driven low on thermocouple open-circuit |
| 13 (–ALM) | Alarm emitter/reference | Emitter terminal of alarm transistor; tied to COM or V– to define alarm logic polarity and sink path |
| 14 (–IN) | Thermocouple negative input | Differential input terminal for alumel (Type K) thermocouple wire; matched impedance and noise rejection with Pin 1 |
Key Features
| Feature | Design Value |
|---|---|
| Laser wafer-trimmed Type K calibration | Gain = 247.3 and offset = 11 µV factory-set to match ANSI Type K thermocouple sensitivity (40.44 µV/°C) at +25°C |
| Configurable operating mode | Single-wire pin strap (FB→VO) enables standalone Celsius thermometer; external voltage on FB enables setpoint comparator without redesign |
| Integrated thermocouple failure alarm | Self-contained open-circuit detector with TTL-compatible +ALM output and flexible grounding via –ALM terminal |
| Dual-supply flexibility | Operates from +5 V only (0°C to +300°C) or ±5 V to ±15 V (–200°C to +1250°C), with output swing referenced to either rail |
| Recalibration terminals | +C/–C and +T/–T pins allow field adjustment for Type E, Type T, or custom thermocouple types using two or three resistors |
Applications
| Industrial Furnace Control | Medical Sterilization Monitoring |
|---|---|
Use Scenario: Continuous temperature regulation in batch ovens where thermal uniformity and alarm response time are critical. IC Role / Device Role / Timing Role: Primary thermocouple signal conditioner and cold-junction compensator; provides direct 10 mV/°C analog output to PLC analog input module. Use Value: Eliminates need for external ice bath or digital compensation algorithms; ±3°C accuracy ensures compliance with ASTM E2877 sterilization cycle validation requirements. |
Use Scenario: Real-time chamber temperature tracking during autoclave cycles, requiring fail-safe open-wire detection. IC Role / Device Role / Timing Role: Thermocouple interface IC with integrated alarm; +ALM output triggers hardware interlock on thermocouple break. Use Value: Reduces BOM count by replacing discrete op-amp + reference + comparator solution; alarm assertion <100 µs enables immediate cycle abort per ISO 17665. |
| HVAC Zone Sensor Interface | Lab Equipment Temperature Logger |
Use Scenario: Distributed RTU-based HVAC control using Type K thermocouples across multiple zones with long cable runs. IC Role / Device Role / Timing Role: Signal conditioning front-end with common-mode noise rejection; operates from 24 VDC single supply. Use Value: Differential input rejects induced noise on 10+ meter thermocouple leads; low quiescent current (160 µA) extends battery life in wireless sensor nodes. |
Use Scenario: Benchtop data logger capturing temperature vs. time for material testing, requiring traceable calibration and stable output. IC Role / Device Role / Timing Role: Standalone Celsius transducer (inputs shorted, FB→VO); outputs calibrated voltage directly to 16-bit SAR ADC. Use Value: Factory-trimmed ±3°C accuracy eliminates per-unit calibration labor; hermetic DIP package ensures long-term drift <0.05°C/year per MIL-STD-883. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar thermocouple amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX31855KASA+ | Digital SPI output (14-bit), integrated cold-junction compensation, no analog output; requires microcontroller interface | Best for digital systems needing automatic linearization and fault diagnostics; unsuitable for analog-only signal chains | Select MAX31855KASA+ when migrating to digital acquisition and firmware-based alarm handling is acceptable |
| AD8495ARMZ | Analog output (5 mV/°C), optimized for Type K, ±2°C accuracy, 8-pin SOIC package, lower supply current (95 µA) | Smaller footprint and lower power, but lacks alarm outputs and setpoint comparator mode; no recalibration terminals | Select AD8495ARMZ for space-constrained, low-power analog systems where alarm and configurability are not required |
Compared with MAX31855KASA+ and AD8495ARMZ, the AD595AQ uniquely combines analog 10 mV/°C output, hardware alarm signaling, pin-strappable setpoint control, and field recalibration capability - making it the only choice for legacy analog control loops requiring drop-in thermocouple signal conditioning with fail-safe monitoring.
Availability
AD595AQ is available at Aetrix Electronics and suitable for industrial furnace control, medical sterilization monitoring, and HVAC zone sensor applications requiring stable component supply, long-term lifecycle support, and hermetically sealed reliability.
Supply support for AD595AQ 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 AD594/AD595 product line was engineered specifically for precision thermocouple signal conditioning in harsh industrial environments, integrating cold-junction compensation, amplification, and alarm functionality into a single monolithic IC.
FAQ
What is the primary thermocouple type supported by the AD595AQ?
The AD595AQ is laser wafer-trimmed for Type K (chromel–alumel) thermocouples, delivering a nominal 10 mV/°C output calibrated to ANSI standard Type K sensitivity of 40.44 µV/°C at +25°C. It can also interface with Type T thermocouples within 0°C to +50°C ambient with ≤0.2°C additional calibration error, as documented in the AD595AQ datasheet revision C.
Can the AD595AQ operate from a single +5 V supply?
Yes, the AD595AQ supports single-supply operation from +5 V (V+ = +5 V, V– = 0 V), enabling 0°C to +300°C measurement with output swing from 0 V to +3 V. In this configuration, Pin 7 (V–) and Pin 4 (COM) are tied together. Self-heating remains below 0.065°C due to 160 µA quiescent current, preserving measurement integrity.
How does the thermocouple failure alarm work on the AD595AQ?
The AD595AQ integrates a dedicated open-circuit detector that monitors thermocouple lead continuity. When either Pin 1 (+IN) or Pin 14 (–IN) becomes disconnected, the +ALM output (Pin 12) is actively pulled low while –ALM (Pin 13) provides the emitter return path. This TTL-compatible alarm signal can directly drive LEDs, optocouplers, or logic gates without external components.
What is the purpose of the +C, –C, +T, and –T pins on the AD595AQ?
These pins provide access to the internal ice-point compensation network: +C/–C supply temperature-dependent bias currents, while +T/–T deliver complementary Kelvin-proportional voltages. They enable field recalibration for alternate thermocouple types (e.g., Type E) using external resistors - a capability not found in most competing thermocouple amplifiers like the AD8495ARMZ.
Does the AD595AQ require external components for basic operation?
No, the AD595AQ functions as a complete thermocouple conditioner with no external components required for basic linear amplification mode: connect thermocouple to Pins 1/14, tie Pin 8 (FB) to Pin 9 (VO), apply +5 V to Pin 11, ground Pin 4/7, and read output at Pin 9. External resistors or capacitors are only needed for setpoint control, recalibration, or low-gain stability compensation.
AD595AQ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 14-CDIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Thermocouple Amplifier
- Sensor Type:
- External
- Sensing Temperature:
- -
- Accuracy:
- ±3°C(Max)
- Topology:
- Ice Point Compensation, Overload Detection
- Output Type:
- Voltage
- Output Alarm:
- Yes
- Output Fan:
- No
- Voltage - Supply:
- 5V ~ ±15V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 14-CERDIP
AD595AQ FAQ
1.How can I place an order for AD595AQ through Aetrix?
Please submit a Request for Quotation (RFQ) for AD595AQ 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 AD595AQ reliable?
The price and inventory of AD595AQ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD595AQ is usually 5 days.
3.What payment methods are accepted for AD595AQ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD595AQ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD595AQ?
AD595AQ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD595AQ 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 AD595AQ?
For technical support, including AD595AQ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD595AQ requirements.
6.How does Aetrix verify that AD595AQ is sourced from the original manufacturer or authorized distributors?
All AD595AQ 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 AD595AQ meets industry standards.
7.What is the process for return or replacement of AD595AQ?
All AD595AQ units undergo pre-shipment inspection (PSI). If there is an issue with AD595AQ, 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 AD595AQ part is unused and in its original packaging.
Return procedure for AD595AQ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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