Texas Instruments REF1004I-2.5

Overview

REF1004I-2.5 from Texas Instruments is a two-terminal micropower bandgap voltage reference diode delivering 2.500 V ±20 mV initial accuracy at 100 µA, with 20 ppm/°C temperature coefficient and 0.2–0.6 Ω reverse dynamic impedance over –40°C to +85°C. It operates from 20 µA minimum current up to 20 mA load, supporting precision A/D and D/A converters in portable medical instrumentation.

For engineers reviewing the REF1004I-2.5 datasheet, REF1004I-2.5 pinout, REF1004I-2.5 application, or REF1004I-2.5 equivalent, key selection criteria include its industrial temperature range, low operating current, long-term stability (20 ppm/kHr), noise performance (120 µV RMS, 10 Hz–10 kHz), and SOIC-8 package compatibility with legacy LT1004/LM385 footprints.

Technical Context

The REF1004I-2.5 implements a bandgap-based two-terminal shunt reference architecture with internal curvature compensation, enabling stable 2.5 V output across –40°C to +85°C without external components. Its design eliminates need for series pass transistors or bias resistors in basic configurations.

It maintains regulation under reverse-biased operation with 1 mV reverse breakdown voltage change over 1 mA–20 mA current range and exhibits 60–120 µV RMS wideband noise. The device achieves 20 ppm/°C tempco via trimmed on-chip resistor networks and laser-trimmed reference core.

Key Specifications

Pinout & Package

REF1004I-2.5 is housed in an 8-lead SOIC (D) package per TI drawing 182, with pin 1 orientation marked by notch or dot. The device uses two-terminal shunt topology: Cathode connects to input supply, Anode connects to ground or load return path.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar shunt voltage reference applications.

Compared with LT1004CZ-2.5 and LM385B-2.5/NOPB, REF1004I-2.5 delivers tighter initial accuracy (±20 mV vs. ±50/±30 mV), lower tempco (20 vs. 50/100 ppm/°C), and guaranteed industrial temperature support - making it optimal for calibrated portable instrumentation where measurement integrity must be maintained across environmental stress.

Availability

REF1004I-2.5 is available at Aetrix Electronics and suitable for portable medical instrumentation, battery-powered test equipment, and A/D and D/A converters requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for REF1004I-2.5 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 company headquartered in Dallas, Texas, specializing in analog and embedded processing technologies with broad industrial, automotive, and personal electronics reach.

The REF1004 family was designed as a cost-effective, high-stability micropower shunt reference to replace screened LT1004 and LM385 variants in portable and battery-critical systems demanding accuracy without premium screening costs.

FAQ

What is the operating temperature range for REF1004I-2.5?

The REF1004I-2.5 is characterized for continuous operation from –40°C to +85°C. This industrial temperature grade is confirmed in the Electrical Specifications table and Absolute Maximum Ratings section of the official datasheet. Unlike the REF1004C-2.5 variant (0°C to +70°C), the 'I' suffix explicitly denotes this extended range, making REF1004I-2.5 suitable for outdoor instrumentation and automotive cabin applications where ambient extremes occur.

Does REF1004I-2.5 require external components to function?

No, REF1004I-2.5 operates as a two-terminal shunt reference and requires no external capacitors or resistors for basic regulation. A single current-setting resistor from supply to cathode (Pin 1) is sufficient - for example, a 24 kΩ resistor from a 5 V rail delivers ~100 µA bias current. External bypass capacitors (e.g., 5 µF) are optional and used only to further reduce high-frequency noise in sensitive ADC applications; they are not mandatory for regulation.

Is REF1004I-2.5 pin-compatible with LT1004-2.5?

Yes, REF1004I-2.5 is a documented drop-in replacement for LT1004-2.5 in SOIC-8 packaging. Both devices share identical pinout (Cathode on Pin 1, Anode on Pin 4, NC on remaining pins), same 8-lead SOIC footprint, and compatible electrical interface. Texas Instruments explicitly states this compatibility in the device description, enabling direct substitution on existing LT1004-2.5 layouts without PCB modification.

What is the maximum load current REF1004I-2.5 can sink?

The REF1004I-2.5 is specified to operate stably up to 20 mA total cathode current, which includes both load current and its own operating current. For example, if biased at 100 µA, it can supply up to 19.9 mA to an external load while maintaining regulation. This capability is verified in the "OPERATES UP TO 20mA" feature list and supported by the Electrical Specifications table showing performance across 1 mA to 20 mA test conditions.

How does the long-term stability of REF1004I-2.5 compare to standard bandgap references?

REF1004I-2.5 offers 20 ppm/kHr long-term stability at 25°C, measured under controlled conditions with 100 µA bias. This is significantly better than typical untrimmed bandgap references (often >100 ppm/kHr) and matches high-reliability references used in metrology-grade equipment. The value reflects actual accelerated life-test data, not extrapolated projections, and directly impacts calibration interval length in portable test instruments using REF1004I-2.5.