LM4040

LM4040 Precision Voltage Reference

Overview

The LM4040 is a precision voltage reference designed for space-critical applications, offering high accuracy and stability in an ultra-compact form factor. Available in the sub-miniature SOT-23 (3 mm x 1.3 mm) surface-mount package as well as the through-hole TO-92 package, the LM4040 is engineered to deliver reliable performance without requiring an external stabilizing capacitor. Its advanced design ensures stability across all capacitive loads, simplifying integration into a wide range of circuit designs.

This component is ideal for applications demanding precision voltage references, such as data converters, power supplies, and portable electronics. With several fixed reverse breakdown voltage options, the LM4040 provides flexibility while maintaining tight tolerances and low temperature drift.

Features

• Compact Form Factor: Available in space-saving SOT-23 (3 mm x 1.3 mm) and TO-92 packages.
• No External Capacitor Required: Advanced design ensures stability without the need for an external stabilizing capacitor.
• Wide Operating Range: Supports a broad operating current range, typically from 60 µA to 12 mA.
• High Accuracy: Tight initial tolerances of ±0.1%, ±0.2%, and ±0.5%, depending on grade.
• Low Temperature Drift: Excellent temperature stability with low drift over the operating range.
• Multiple Voltage Options: Fixed reverse breakdown voltages available at 2.048V, 2.5V, 3V, 3.3V, 4.096V, and 5V.
• Wide Operating Temperature Range: Performs reliably from -40°C to +125°C.
• Low Output Noise: Minimal noise generation for precision applications.

Applications

The LM4040 is widely used in precision electronic systems where stable voltage references are critical. Key applications include:

• Data Converters (ADCs/DACs): Provides a stable reference voltage for accurate analog-to-digital and digital-to-analog conversion.
• Power Supply Regulation: Ensures consistent voltage levels in switching and linear regulators.
• Portable and Battery-Powered Devices: Ideal for low-power applications due to its minimal current draw.
• Industrial Control Systems: Used in sensors, instrumentation, and control circuits requiring precision voltage references.
• Automotive Electronics: Suitable for onboard systems where temperature stability and reliability are crucial.
• Medical Equipment: Provides accurate voltage references for diagnostic and monitoring devices.

Electrical Characteristics

The following table summarizes the key electrical specifications of the LM4040:

• Reverse Breakdown Voltage (V_REF): 2.048V, 2.5V, 3V, 3.3V, 4.096V, 5V (selectable variants)
• Initial Accuracy: ±0.1% (A grade), ±0.2% (B grade), ±0.5% (C grade)
• Operating Current Range: 60 µA (min) to 12 mA (max)
• Dynamic Impedance: As low as 0.5 Ω (typical at 1 mA)
• Temperature Coefficient: Typically 50 ppm/°C (A grade)
• Line Regulation: 0.05%/V (typical)
• Load Regulation: 0.1%/mA (typical)
• Long-Term Stability: 20 ppm/1000 hours (typical)
• Output Noise Voltage (10 Hz to 10 kHz): 35 µV_RMS (typical)

Package Information

The LM4040 is available in two industry-standard packages, providing flexibility for different PCB layouts and assembly processes:

• SOT-23 (3 mm x 1.3 mm): A surface-mount package ideal for space-constrained designs. Pinout consists of three pins: Cathode, Anode, and No Connection (NC).
• TO-92: A through-hole package suitable for prototyping and applications requiring manual assembly. Pinout includes Cathode (Pin 1), Anode (Pin 2), and No Connection (Pin 3).

Typical Performance Characteristics

The LM4040 exhibits consistent performance across various operating conditions:

• Voltage vs. Current: Stable output voltage across the full operating current range.
• Temperature Stability: Minimal deviation in output voltage over the -40°C to +125°C range.
• Load Transient Response: Rapid recovery from load changes due to low dynamic impedance.
• Noise Performance: Low output noise ensures clean voltage references for sensitive analog circuits.

Design Considerations

When integrating the LM4040 into a circuit, the following guidelines should be observed:

• Current Limiting Resistor: A series resistor must be used to limit current through the LM4040. The value can be calculated based on the supply voltage and desired operating current.
• PCB Layout: For optimal performance, minimize trace lengths and place decoupling capacitors close to the device.
• Thermal Management: Although the LM4040 has low power dissipation, proper thermal design is recommended for high-temperature environments.

Conclusion

The LM4040 precision voltage reference combines high accuracy, stability, and ease of use in compact packages, making it an excellent choice for a wide range of applications. Its no-capacitor-required design simplifies circuit implementation while delivering reliable performance across varying operating conditions. Whether used in portable electronics, industrial systems, or precision measurement equipment, the LM4040 provides a robust voltage reference solution.