Texas Instruments REF1004C-1.2

Overview

REF1004C-1.2 from Texas Instruments is a two-terminal micropower bandgap voltage reference diode delivering 1.235 V nominal output with ±4 mV initial accuracy, 20 ppm/°C temperature coefficient, and operation down to 10 µA supply current. It serves as a precision low-power reference in battery-operated instrumentation, A/D converters, and portable medical devices.

For engineers reviewing the REF1004C-1.2 datasheet, REF1004C-1.2 pinout, REF1004C-1.2 application, or REF1004C-1.2 equivalent, key selection criteria include its 8-pin SOIC package, 0°C to +70°C operating range, reverse breakdown configuration, and compatibility with LT1004 and LM185/385 replacement paths.

Technical Context

The REF1004C-1.2 operates as a two-terminal shunt reference, requiring an external current-setting resistor to establish bias current between anode and cathode terminals. Its bandgap core achieves stable 1.235 V output across 10 µA to 20 mA operating current, with dynamic impedance under 0.6 Ω at 100 µA.

It exhibits 60 µV RMS wideband noise (10 Hz–10 kHz), 20 ppm/KHr long-term stability at 25°C, and reverse voltage drift of ≤1.5 mV over 1 mA to 20 mA current variation - all specified for the C-grade (0°C to +70°C) variant.

Key Specifications

Pinout & Package

REF1004C-1.2 is housed in an 8-lead SOIC (D) package per TI drawing 182, with pin 1 marked by a notch or dot. The device uses a two-terminal shunt topology: only pins 4 (Anode) and 5 (Cathode) are electrically active; all other pins (1, 2, 3, 6, 7, 8) are No Connect (NC).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT1004CZ-1.2 and LM385B-1.2/NOPB, REF1004C-1.2 delivers tighter initial accuracy, lower dynamic impedance, and verified long-term stability - making it the preferred choice for calibrated portable instrumentation and medical-grade converters where drift and noise directly impact regulatory compliance.

Availability

REF1004C-1.2 is available at Aetrix Electronics and suitable for battery-powered test equipment, portable medical instrumentation, and A/D and D/A converters requiring stable component supply, consistent parametric performance, and long-lifecycle availability.

Supply support for REF1004C-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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and digital signal solutions for industrial, automotive, and personal electronics markets.

The REF1004 family was designed to replace legacy shunt references with superior micropower efficiency and factory-trimmed accuracy - specifically targeting portable, battery-constrained systems needing precision without complexity.

FAQ

What is the operating temperature range for REF1004C-1.2?

The REF1004C-1.2 is characterized for operation from 0°C to +70°C. This commercial-grade temperature specification is explicitly defined in the ordering information table and applies to all electrical parameters unless otherwise noted. The "C" suffix denotes this grade, distinguishing it from the extended-range REF1004I-1.2 (–40°C to +85°C). REF1004C-1.2 maintains its ±4 mV initial accuracy and 20 ppm/°C temperature coefficient across this full range.

How is REF1004C-1.2 connected in a circuit?

REF1004C-1.2 is a two-terminal shunt reference: Pin 4 (Anode) connects to ground or the low side of a current-setting resistor, and Pin 5 (Cathode) provides the 1.235 V reference output. All other pins (1, 2, 3, 6, 7, 8) are No Connect and must remain unconnected. A typical configuration uses a series resistor from the supply to Pin 5, with Pin 4 grounded - establishing bias current between 10 µA and 20 mA. REF1004C-1.2 regulates by sinking excess current through its internal bandgap core.

Does REF1004C-1.2 require an external capacitor for stability?

No, REF1004C-1.2 does not require an external output capacitor for basic stability, as confirmed by the Typical Operating Circuit diagram and absence of capacitor recommendations in the datasheet. However, a 5 µF capacitor is shown in Figure 2 (Micropower Reference from 9V Battery) to reduce noise and improve transient response in high-impedance source applications. For low-noise A/D converter use, adding 1–10 µF ceramic capacitance at the Cathode (Pin 5) is recommended to suppress supply ripple and enhance PSRR - but it is not mandatory for regulation.

What is the maximum load current REF1004C-1.2 can drive?

REF1004C-1.2 is rated to operate up to 20 mA total current, meaning the sum of load current plus reference bias current must not exceed 20 mA. Since minimum operating current is 10 µA, the practical maximum load current is just under 20 mA - provided the external current-setting resistor supplies sufficient headroom. The device maintains regulation with <1.5 mV output change across 1 mA to 20 mA current variation, confirming robustness under dynamic loading. REF1004C-1.2 is not intended as a power source but as a precision reference node.

Is REF1004C-1.2 pin-compatible with LT1004?

Yes, REF1004C-1.2 is a documented drop-in replacement for LT1004, as stated in the Applications section of the datasheet: "REF1004 is a drop-in replacement for the LT1004." Both devices use identical 8-lead SOIC packaging with Anode on Pin 4 and Cathode on Pin 5, and all NC pins align. Electrical compatibility includes matching reference voltage (1.2 V), operating current range, and shunt topology - enabling direct substitution without layout changes or firmware updates in existing LT1004 designs.