Texas Instruments LT1004IDR-1-2

Overview

LT1004IDR-1-2 from Texas Instruments is a two-terminal micropower band-gap voltage reference IC delivering 1.235 V nominal output with ±4 mV initial accuracy, 20 ppm/°C temperature coefficient, and 0.6 Ω reference impedance at 100 µA - designed for precision low-power systems including portable test instruments and battery-operated sensor interfaces.

For engineers reviewing the LT1004IDR-1-2 datasheet, LT1004IDR-1-2 pinout, LT1004IDR-1-2 application, or LT1004IDR-1-2 equivalent, key selection criteria include its −40°C to 85°C industrial temperature range, SOIC-8 package, 8 µA minimum operating current, 20 mA max reverse current capability, and compatibility with current-loop instrumentation and cold-junction compensation circuits.

Technical Context

The LT1004IDR-1-2 implements a monolithic band-gap reference architecture with internal trimming for high initial accuracy and low thermal drift. Its two-terminal configuration operates in either forward-biased (anode-to-cathode) or reverse-biased (cathode-to-anode) mode depending on circuit topology, enabling use as a shunt reference in both grounded-cathode and grounded-anode configurations.

It features very low dynamic impedance (≤0.6 Ω at 100 µA), broadband noise of 60–120 µV RMS (10 Hz–10 kHz), and long-term stability of 20 ppm/khr - all achieved while maintaining micropower operation down to 8 µA minimum reference current and supporting up to 20 mA reverse current without degradation.

Key Specifications

Pinout & Package

LT1004IDR-1-2 is housed in an 8-pin SOIC (D) package with 1.27 mm lead pitch and 1.75 mm max height. Pins 6 and 8 are internally connected cathodes; pins 1, 3, 4, and 7 are no-connect terminals. Only pins 2 (Anode) and 5 (Cathode) are functional.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM385BIMX-1.2, LT1004IDR-1-2 delivers 3× better accuracy and 5× lower tempco; versus REF1012AIDR, it offers two-terminal simplicity and micropower operation at the cost of moderate precision - making it uniquely suited for compact, battery-constrained industrial instrumentation.

Availability

LT1004IDR-1-2 is available at Aetrix Electronics and suitable for portable meter reference, current-loop instrumentation, and battery-operated systems requiring stable component supply with guaranteed long-term availability and consistent parametric performance.

Supply support for LT1004IDR-1-2 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 over 90 years of innovation in precision analog ICs and power management solutions.

The LT1004 series was developed as a micropower, high-accuracy shunt voltage reference family targeting portable, battery-powered, and industrial instrumentation applications where low quiescent current and stable reference voltage are critical.

FAQ

What is the operating temperature range of the LT1004IDR-1-2?

The LT1004IDR-1-2 is characterized for operation from −40°C to +85°C, meeting industrial temperature requirements. This range is confirmed in the ordering information table and electrical characteristics section of the SLVS022M datasheet, where "LT1004I" denotes the industrial-grade variant. The device maintains its ±4 mV initial accuracy and 20 ppm/°C temperature coefficient across this full range.

Is the LT1004IDR-1-2 pin-compatible with the LM285 or LM385 series?

Yes, the LT1004IDR-1-2 is explicitly documented as a pin-for-pin replacement for the LM285 and LM385 series. It uses the same SOIC-8 package with identical pin 2 (Anode) and pin 5 (Cathode) assignments, and shares the same no-connect pin configuration (pins 1, 3, 4, 7). However, LT1004IDR-1-2 improves upon those legacy parts with tighter initial accuracy (±4 mV vs ±20 mV) and lower temperature coefficient (20 ppm/°C vs 50–100 ppm/°C).

What is the minimum reference current required for stable operation of the LT1004IDR-1-2?

The LT1004IDR-1-2 requires a minimum reference current of 8 µA to maintain regulation, as specified in the "electrical characteristics" table under I_Z(min). Below this threshold, the reference voltage deviates from its nominal 1.235 V value. This ultra-low minimum current enables use in energy-harvesting systems and always-on monitoring circuits where supply current is severely constrained.

Can the LT1004IDR-1-2 be used in a grounded-anode configuration?

Yes, the LT1004IDR-1-2 supports both grounded-cathode (standard shunt) and grounded-anode configurations. In grounded-anode mode, the anode (pin 2) connects to system ground and the cathode (pin 5) supplies the reference voltage - as demonstrated in Figure 26 ("1.2-V Reference From 1.5-V Battery") of the datasheet. This flexibility allows adaptation to diverse supply architectures without external components.

What is the reference impedance of the LT1004IDR-1-2 and why does it matter?

The LT1004IDR-1-2 exhibits a typical reference impedance of 0.6 Ω at 100 µA, rising to 1.5 Ω over the full temperature range. This low dynamic impedance ensures minimal voltage variation (<1 mV) under load current changes - critical when driving op-amp inputs or ADC reference pins directly. High impedance would cause regulation errors proportional to load current, degrading measurement accuracy in precision analog signal chains.