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Texas Instruments XTR108EA/2K5
- Part No.:
- XTR108EA/2K5
- Manufacturer:
- Texas Instruments
- Category:
- Sensor and Detector Interfaces
- Package:
- 24-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
XTR108EA/2K5.pdf
- Description:
- IC CRNT TRANSMITTER 24SSOP/QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,667
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Product details
Overview
XTR108EA/2K5 from Texas Instruments is a programmable, two-wire 4–20mA current-loop transmitter IC designed for RTD and bridge sensor signal conditioning. It integrates an autozeroed PGA (gain 6.25–400 V/V), dual programmable current sources (±195 µA fine adjustment), digital linearization, 5.1V sub-regulator, SPI interface, and NAMUR NE43-compliant over/under-scale fault detection. Used in industrial process transmitters where calibration stability and sensor excitation precision are critical.
For engineers reviewing the XTR108EA/2K5 datasheet, XTR108EA/2K5 pinout, XTR108EA/2K5 application, or XTR108EA/2K5 equivalent, key selection considerations include its SSOP-24 package, IRET-referenced analog architecture, 0.01% nonlinearity, ±1.5 µA/°C zero drift, and requirement for external depletion-mode MOSFET (e.g., Supertex DN2540) to support loop supply up to 24V.
Technical Context
The XTR108EA/2K5 implements a fully analog signal path with a 6-channel multiplexer enabling flexible sensor excitation and input routing-each V/I-x pin supports simultaneous MUX input and IREF output. Its autozeroed instrumentation amplifier operates at 6.5 kHz chopper frequency and achieves ±10 µV RTI offset with 105 dB CMRR at G = 6.25.
Digital calibration is executed via SPI using two independent chip selects: CS1 for host microcontroller communication and CS2 for external EEPROM access during power-up. Linearization uses a dedicated DAC (8-bit, 3.9 nA/mV step) and RLIN resistor to correct second-order RTD nonlinearity, while over/under-scale limiting employs 4-bit (20.7–28.1 mA) and 3-bit (2.17–3.55 mA) DACs compliant with NAMUR NE43 thresholds.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current Range | 4–20 mA, digitally adjustable with ±0.5 mA over/under-scale resolution per NAMUR NE43 |
| PGA Gain Range | 6.25–400 V/V in binary steps; enables transconductance scaling from 49–3150 mA/V via RVI = 6.34 kΩ |
| Zero Adjustment Resolution | 1.8 µA/step coarse + 0.0018 mA/step fine DAC; 12-bit effective resolution for offset compensation |
| Input Nonlinearity | 0.01% of full scale at 50 mV ideal input; verified across –40°C to +85°C operating range |
| Sub-Regulator Output | 5.1 V ±0.3 V (4.8–5.4 V), with ±50 ppm/°C drift and ±0.03 mV/V loop-supply rejection |
| Reference Voltage | 1.193 V internal bandgap, ±5 ppm/°C typical drift, REFIN/REFOUT pins require direct connection for internal use |
| Operating Temperature | –40°C to +85°C ambient; junction temperature rated to +165°C with θJA = 100°C/W |
Pinout & Package
Package: SSOP-24 (DBQ), 0.635 mm pitch, moisture sensitivity level 3, rated for –40°C to +85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| V/I-0 to V/I-5 | Multiplexer Input / Excitation Output | Bi-directional terminals supporting simultaneous PGA input sensing and IREF1/IREF2 excitation delivery to RTD/bridge sensors |
| CFILTER | PGA Noise Filter Node | Accepts 0.01 µF capacitor to ground (IRET) to reduce chopper feedthrough ripple at high PGA gains |
| RLIN | Linearization Current Scaling | Connects external resistor (recommended 15.8 kΩ) to set parabolic correction coefficient for RTD nonlinearity |
| VO | PGA Output Voltage | Amplified differential sensor output; routed to IIN via RVI to generate 4–20 mA loop current |
| IIN | Current Amplifier Input | Non-inverting input of output current amplifier; referenced to IRET; accepts voltage-to-current conversion node |
| IO | Loop Output Current | 4–20 mA output terminal; requires external depletion-mode MOSFET (e.g., DN2540) for high-voltage compliance |
| IRET | Return Reference Node | Common return for all external circuitry, sensor bias, and internal supplies; all voltages referenced to this pin |
| VS | Sub-Regulator Output | 5.1 V regulated supply for internal circuits and optional external components; requires CREG = 2.2 µF bypass |
| VGATE | MOSFET Gate Driver | Drives gate of external n-channel depletion-mode FET; CGATE value must prevent VS overshoot >7.5 V |
| CS1, SCLK, SDIO | SPI Host Interface | CMOS-compatible serial bus (CS1 active-low) for calibration controller communication; logic levels referenced to IRET |
| CS2 | EEPROM Select | Dedicated chip select for external SPI EEPROM; enables autonomous calibration constant retrieval at power-up |
| RSET | Reference Current Set | Connects 12.1 kΩ resistor to REFOUT to establish 492 µA base excitation current for 100 Ω RTDs |
| REFOUT / REFIN | Bandgap Reference I/O | 1.193 V internal reference; REFIN must be shorted to REFOUT unless external ≤1.4 V reference is used |
| OPA +IN / –IN / OUT | Uncommitted Op Amp | General-purpose amplifier with ±2 mV offset; usable for I-to-V conversion or auxiliary signal conditioning |
Key Features
| Feature | Design Value |
|---|---|
| Digital Calibration Architecture | Two independent SPI interfaces (CS1 for host, CS2 for EEPROM) eliminate manual potentiometer trimming and enable field recalibration |
| RTD-Specific Linearization | Programmable second-order correction via RLIN resistor and 8-bit DAC delivers up to 40:1 nonlinearity improvement for Pt100 sensors |
| NAMUR NE43 Fault Signaling | Configurable over-scale (21–28.5 mA) and under-scale (2.2–3.6 mA) limits with ±10% DAC accuracy for standardized burnout detection |
| Autozeroed Instrumentation Amplifier | 6.5 kHz chopper-stabilized PGA achieves ±10 µV RTI offset and 0.01% nonlinearity without external nulling components |
| Integrated Sub-Regulator | On-chip 5.1 V regulator with external MOSFET support enables operation from 7.5–24 V loop supply while maintaining low-voltage CMOS core integrity |
Applications
| Remote RTD Transmitters | Pressure Bridge Transmitters |
|---|---|
Use Scenario: Two-wire 4–20 mA transmitter located in hazardous area measuring Pt100 RTD temperature with 200 m cable run. IC Role / Device Role / Timing Role: XTR108EA/2K5 performs cold-junction compensation, RTD excitation, PGA amplification, digital linearization, and loop-current generation. Use Value: Eliminates manual trim pots and external op amps; achieves 0.01% linearity after digital calibration stored in external EEPROM. | Use Scenario: Industrial pressure sensor module converting Wheatstone bridge output (10–50 mV) into 4–20 mA for PLC input. IC Role / Device Role / Timing Role: XTR108EA/2K5 configures V/I-x pins for ratiometric bridge excitation, applies PGA gain of 200 V/V, and digitizes zero/span via SPI. Use Value: Compensates for bridge offset and nonlinearity in real time; supports NAMUR NE43 fault reporting for predictive maintenance. |
| Strain Gage Transmitters | Weighing Systems |
Use Scenario: Load cell interface in tank weighing system requiring high common-mode rejection and low drift over temperature. IC Role / Device Role / Timing Role: XTR108EA/2K5 uses autozeroed PGA with 105 dB CMRR and 6.5 kHz chopper to reject 50/60 Hz interference and suppress thermal EMFs. Use Value: Delivers ±0.2 µA/°C zero drift performance without external auto-zero circuitry; maintains calibration over –40°C to +85°C. | Use Scenario: Platform scale with four 350 Ω strain gages in full-bridge configuration feeding into centralized transmitter. IC Role / Device Role / Timing Role: XTR108EA/2K5 routes bridge outputs through multiplexer, applies 12.5 V/V PGA gain, and generates fault-indicating 3.55 mA under-scale output on open-circuit detection. Use Value: Enables single-chip solution for bridge excitation, amplification, linearization, and 4–20 mA output with integrated NAMUR-compliant diagnostics. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 4–20mA transmitter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| XTR115UA/2K5 | Fixed 4–20 mA output only; no digital linearization, no PGA gain control, no SPI interface; includes integrated MOSFET | Targeted at cost-sensitive, fixed-range transmitters without field calibration needs | Select XTR115UA/2K5 only if linearization, programmable gain, and EEPROM-based calibration are unnecessary |
| AD421BN | 16-bit DAC-based architecture; no integrated PGA or linearization; requires external op amps and references; HART-compatible | Designed for HART-enabled smart transmitters with digital communication overlay | Choose AD421BN when HART protocol support and 4–20 mA + digital data transmission are required |
Compared with XTR108EA/2K5, XTR115UA/2K5 sacrifices programmability and sensor-specific signal conditioning for lower BOM count and integrated power FET, while AD421BN trades analog integration for higher-resolution digital control and HART compatibility-neither offers the XTR108EA/2K5's combined PGA, linearization, and dual-DAC calibration architecture.
Availability
XTR108EA/2K5 is available at Aetrix Electronics and suitable for remote RTD transmitters, pressure bridge transmitters, and industrial process control systems requiring stable component supply, long-term calibration retention, and NAMUR NE43-compliant fault signaling.
Supply support for XTR108EA/2K5 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies for industrial, automotive, and communications markets.
The XTR series is TI's dedicated family of 4–20 mA current-loop transmitters engineered for high-precision sensor signal conditioning in harsh industrial environments, with emphasis on programmability, fault diagnostics, and calibration stability.
FAQ
What is the minimum loop supply voltage required for XTR108EA/2K5 operation?
The XTR108EA/2K5 requires a minimum loop supply voltage of 7.5 V when used with the Supertex DN2540 external depletion-mode MOSFET, as specified in the SBOS187C datasheet. This value may vary slightly with alternative MOSFETs due to differences in RDS(on) and gate threshold characteristics. The device itself operates from its internal 5.1 V sub-regulator (VS pin), but the external FET determines the overall loop compliance. Always verify voltage drop across the FET at maximum load current (20 mA) and worst-case ambient temperature.
Does XTR108EA/2K5 support direct RTD connection without external components?
Yes, the XTR108EA/2K5 supports direct 2-, 3-, or 4-wire RTD connection using its six V/I-x pins and integrated current sources. For a standard 100 Ω Pt100 RTD, connect RSET = 12.1 kΩ to set 492 µA excitation, route IREF1 to RTD leg via V/I-0, and sense differential voltage across V/I-1 and V/I-2. No external op amps, references, or trimmers are needed-the XTR108EA/2K5 handles excitation, amplification, linearization, and 4–20 mA conversion internally.
How is calibration data retained in XTR108EA/2K5 after power loss?
Calibration data for the XTR108EA/2K5 is stored in an external SPI-compatible EEPROM, not internal memory. During power-up, the XTR108EA/2K5 automatically reads calibration constants-including PGA gain, zero DAC settings, linearization coefficients, and over/under-scale limits-from the EEPROM via its dedicated CS2 interface. This ensures persistent calibration across power cycles without battery backup, and allows field updates using a host microcontroller connected via CS1.
Can XTR108EA/2K5 generate a voltage output instead of 4–20 mA?
Yes, the XTR108EA/2K5 can be configured for 0.5–4.5 V voltage output by disabling the output current amplifier and using the PGA output (VO pin) directly. This requires omitting the RVI resistor between VO and IIN, and configuring the output stage for rail-to-rail voltage mode. The uncommitted op amp (OPA OUT) may be used to buffer or level-shift the signal. Note that NAMUR NE43 fault signaling and loop-powered operation are not available in voltage-output mode.
What external components are mandatory for XTR108EA/2K5 basic operation?
Four external components are mandatory for XTR108EA/2K5 operation: (1) an n-channel depletion-mode MOSFET (e.g., Supertex DN2540) for loop supply regulation, (2) RSET = 12.1 kΩ to set base excitation current, (3) RVI = 6.34 kΩ to convert PGA output voltage to 4–20 mA current, and (4) CFILTER = 0.01 µF capacitor from pin 7 to IRET to suppress chopper noise. Additional components (RLIN, EEPROM, bypass capacitors) are required for full functionality including linearization and calibration storage.
XTR108EA/2K5 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 24-SSOP (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Current Transmitter
- Input Type:
- Voltage
- Output Type:
- Voltage
- Current - Supply:
- 20 mA
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SSOP
XTR108EA/2K5 FAQ
1.How can I place an order for XTR108EA/2K5 through Aetrix?
Please submit a Request for Quotation (RFQ) for XTR108EA/2K5 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 XTR108EA/2K5 reliable?
The price and inventory of XTR108EA/2K5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for XTR108EA/2K5 is usually 5 days.
3.What payment methods are accepted for XTR108EA/2K5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for XTR108EA/2K5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for XTR108EA/2K5?
XTR108EA/2K5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your XTR108EA/2K5 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 XTR108EA/2K5?
For technical support, including XTR108EA/2K5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your XTR108EA/2K5 requirements.
6.How does Aetrix verify that XTR108EA/2K5 is sourced from the original manufacturer or authorized distributors?
All XTR108EA/2K5 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 XTR108EA/2K5 meets industry standards.
7.What is the process for return or replacement of XTR108EA/2K5?
All XTR108EA/2K5 units undergo pre-shipment inspection (PSI). If there is an issue with XTR108EA/2K5, 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 XTR108EA/2K5 part is unused and in its original packaging.
Return procedure for XTR108EA/2K5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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