Texas Instruments XTR101BG

Overview

XTR101BG from Texas Instruments is a precision 4–20mA two-wire transmitter IC integrating an instrumentation amplifier, voltage-controlled current source, and dual matched current references. It delivers ≤30µV max offset voltage, ≤0.75µV/°C drift, and 0.01% max nonlinearity for millivolt-level transducer signal conditioning in industrial process control loops.

For engineers reviewing the XTR101BG datasheet, XTR101BG pinout, XTR101BG application, or XTR101BG equivalent, this page provides verified specifications, DIP-14 pin mapping, real-world use cases for RTD/thermocouple transmitters, and validated alternative parts with documented functional differences.

Technical Context

The XTR101BG operates as a single-supply, true two-wire transmitter where power and 4–20mA signal share one wire pair. Its instrumentation amplifier accepts differential inputs (e2 − e1) up to 1V full-scale, biased at +4V to +6V relative to pin 7 (E), with internal laser-trimmed precision enabling direct bridge, thermocouple, and RTD interfacing.

It implements a fixed 4mA quiescent current plus 16mA span modulated by input voltage via external span resistor RS. Dual 1mA matched current sources (pins 10/11) provide excitation and zero-elevation/suppression, while optional external transistor operation reduces thermal feedback for high-accuracy applications.

Key Specifications

Pinout & Package

DIP-14 plastic package (N package designator), 0.300-inch wide body, through-hole mounting. Pin 1 index located at top-left corner when notch faces upward.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4–20mA transmitter applications.

Compared with XTR101AG, the XTR101BG trades minor initial accuracy for lower cost and plastic packaging suited to commercial industrial environments; versus XTR105UA, it retains external transistor flexibility and DIP-14 serviceability at the expense of SO-16 density and integrated reference.

Availability

XTR101BG is available at Aetrix Electronics and suitable for pressure transmitters, temperature transmitters, millivolt transmitters, and industrial data acquisition systems requiring stable component supply across multi-year production cycles.

Supply support for XTR101BG 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 and embedded processing technologies with decades of industrial signal conditioning expertise.

The XTR series was designed specifically for rugged, high-accuracy 4–20mA two-wire transmitter applications in process automation, offering integrated precision amplification, excitation, and loop driving in single-package solutions.

FAQ

What is the maximum allowable input signal voltage for XTR101BG?

The XTR101BG supports a maximum differential input voltage (e2 − e1) of 1V when RS = ∞, decreasing proportionally as RS value decreases. For example, with RS = 278Ω (typical for 100mV FS), full-scale input is limited to ~100mV. Exceeding these limits risks saturation or nonlinear output behavior, as confirmed in the Electrical Characteristics table under "Voltage Range, Full-Scale".

Can XTR101BG operate without an external transistor?

Yes, XTR101BG operates fully functional with its internal transistor for moderate-accuracy applications. The external transistor (e.g., 2N2222 or TIP29B) is optional and used only to reduce thermal drift during 4–20mA span transitions - improving offset stability by up to 5× in high-gain configurations, as shown in Figure 3 of the datasheet.

How is common-mode voltage managed on XTR101BG inputs?

XTR101BG requires both inputs (pins 3 and 4) to be biased between +4V and +6V relative to pin 7 (E). This is achieved using its dual 1mA current sources and external resistor R2 (typically 2.5kΩ), generating a stable +5V common-mode level. Deviations outside this range degrade CMR and introduce measurable offset error per the CMV/CMR section.

What is the purpose of pins 12 and 13 on XTR101BG?

Pins 12 and 13 are optional bandwidth control terminals. Connecting an external capacitor (e.g., 100pF–10nF) between them sets the low-pass cutoff frequency of the input stage, reducing high-frequency noise pickup in electrically noisy industrial environments. The relationship between capacitance and bandwidth is documented in the Typical Characteristics plot "BANDWIDTH vs PHASE COMPENSATION".

Does XTR101BG support thermocouple burn-out detection?

Yes, XTR101BG supports thermocouple burn-out detection inherently in standard configurations. When the thermocouple opens, bias current flowing into the high-impedance +In input forces output current down to ~3.8mA (downscale indication), providing fail-safe status without additional circuitry - as verified in the "THERMOCOUPLE BURN-OUT INDICATION" section and Figures 16–18.