Texas Instruments REF1004I-2.5/2K5

Overview

REF1004I-2.5/2K5 from Texas Instruments is a two-terminal micropower bandgap voltage reference diode delivering 2.500 V ±20 mV initial accuracy, 20 ppm/°C temperature coefficient, and stable operation from –40°C to +85°C in an 8-lead SOIC package. It supports 20 µA minimum operating current, up to 20 mA load, and is used in precision A/D and D/A converters requiring low-power, high-stability reference voltage.

For engineers reviewing the REF1004I-2.5/2K5 datasheet, REF1004I-2.5/2K5 pinout, REF1004I-2.5/2K5 application, or REF1004I-2.5/2K5 equivalent, key selection criteria include initial voltage tolerance, long-term stability (20 ppm/kHr), dynamic impedance (0.2–0.6 Ω), wide-band noise (60–120 µV RMS), and industrial temperature range compliance.

Technical Context

The REF1004I-2.5/2K5 operates as a shunt-mode bandgap reference, requiring external current limiting and functioning analogously to a precision Zener diode. Its internal architecture achieves low dynamic impedance (0.2–0.6 Ω at 100 µA) and minimal voltage drift (20 ppm/°C) across –40°C to +85°C via curvature-compensated bandgap design.

It delivers 2.500 V nominal output with ±20 mV initial accuracy at 100 µA, maintains <1.5 mV voltage change over 1–20 mA current variation, and exhibits 60–120 µV RMS wideband noise (10 Hz–10 kHz), enabling use in high-resolution data acquisition systems where low-noise, low-drift references are critical.

Key Specifications

Pinout & Package

Package: 8-Lead SOIC (D), RoHS-compliant, NIPDAU lead finish, MSL Level-3 (260°C peak reflow).

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-2.5/2K5 uniquely combines industrial temperature range, 20 ppm/°C tempco, and 20 µA minimum current - making it the only option among the three qualified for battery-powered, high-accuracy instrumentation operating continuously across –40°C to +85°C.

Availability

REF1004I-2.5/2K5 is available at Aetrix Electronics and suitable for portable medical instrumentation, battery-powered test equipment, and industrial A/D and D/A converters requiring stable component supply, long-term calibration retention, and consistent SOIC packaging.

Supply support for REF1004I-2.5/2K5 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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and logic ICs with broad industrial, automotive, and communications focus.

The REF1004 family was designed as a cost-effective, high-stability shunt voltage reference for precision data conversion systems where low power, low noise, and long-term reliability are essential - directly addressing limitations of legacy references like LM185 and LT1004.

FAQ

What is the operating temperature range of the REF1004I-2.5/2K5?

The REF1004I-2.5/2K5 is characterized for continuous operation from –40°C to +85°C. This industrial-grade rating is confirmed in the Electrical Specifications table and Absolute Maximum Ratings section of the official datasheet, distinguishing it from the commercial-grade REF1004C-2.5 variant (0°C to +70°C). The "I" suffix explicitly denotes the extended temperature grade.

What is the initial voltage accuracy specification for REF1004I-2.5/2K5?

The REF1004I-2.5/2K5 has an initial accuracy of ±20 mV at 100 µA test current, corresponding to ±0.8% of its 2.500 V nominal output. This value is specified in the "REFERENCE VOLTAGE" row of the Electrical Specifications table under the REF1004I column, and applies across the full –40°C to +85°C temperature range.

Does REF1004I-2.5/2K5 require an external current-limiting resistor?

Yes, REF1004I-2.5/2K5 is a two-terminal shunt reference and requires an external series current-setting resistor between the supply and the cathode (Pins 5 and 7). Typical operating circuits in the datasheet show this configuration, with resistor values selected to maintain current between 20 µA (minimum) and 20 mA (maximum) depending on input voltage and load conditions.

How many pins on REF1004I-2.5/2K5 are functional, and what are their roles?

REF1004I-2.5/2K5 has two functional terminals: Pin 4 (Anode) connects to ground or circuit return, and Pins 5 and 7 (Cathode) are paralleled to deliver the 2.5 V reference output. The remaining five pins (1, 2, 3, 6, 8) are NC (no connect) and must remain unconnected - confirmed by the "Typical Operating Circuit" diagram and Pin Configuration table in the datasheet.

Is REF1004I-2.5/2K5 a drop-in replacement for LT1004 or LM385 devices?

The REF1004I-2.5/2K5 is documented as a drop-in replacement for LT1004 and an upgraded replacement for LM185/LM385 series references, per the "DESCRIPTION" section of the datasheet. However, while pin-compatible with LT1004 in SOIC-8, its improved specs - notably 20 ppm/°C vs. 100 ppm/°C tempco and 20 µA vs. 40 µA min current - require verification of system-level thermal and power constraints before substitution.