LM136-2.5/LM236-2.5/LM336-2.5 Precision Shunt Regulator Diodes

Overview

The LM136-2.5, LM236-2.5, and LM336-2.5 are monolithic integrated circuits designed as precision 2.5V shunt regulator diodes. These devices function as low-temperature-coefficient 2.5V zener diodes with a dynamic impedance of just 0.2Ω. A key feature of the LM136-2.5 series is the inclusion of a third terminal that allows for easy trimming of both the reference voltage and temperature coefficient, making these components highly versatile in precision applications.

These voltage references are particularly useful in digital voltmeters, power supplies, and operational amplifier circuits. Their 2.5V output makes them ideal for deriving stable references from standard 5V logic supplies. Additionally, their shunt regulator operation enables their use in a wide variety of circuit configurations.

Features

• Low Temperature Coefficient: Ensures stable performance across varying temperatures.
• Wide Operating Current Range: Operates reliably from 400µA to 10mA.
• 0.2Ω Dynamic Impedance: Provides excellent regulation characteristics.
• ±1% Initial Tolerance: High precision right out of the box.
• Guaranteed Temperature Stability: Reliable performance under thermal stress.
• Trimmable Temperature Drift: Third terminal allows for fine-tuning of temperature drift.
• Fast Turn-On: Quick response time for immediate regulation.
• Multiple Package Options: Available in TO-92, TO-46, and SO packages for flexibility in design.

Applications

The LM136-2.5 series is designed for a broad range of precision voltage reference applications, including:

• Digital Voltmeters (DVMs): Provides a stable 2.5V reference for accurate measurements.
• Power Supplies: Acts as a shunt regulator to maintain consistent voltage levels.
• Operational Amplifier Circuits: Serves as a precision reference for op-amp configurations.
• 5V Logic Systems: Easily derives a stable 2.5V reference from 5V supplies.
• Portable and Battery-Powered Devices: Low power consumption makes it ideal for energy-sensitive applications.

Electrical Characteristics

Absolute Maximum Ratings

Note: Exceeding these ratings may cause permanent damage to the device.

• Operating Temperature Range:
  • LM136-2.5: -55°C to +125°C
  • LM236-2.5: -25°C to +85°C
  • LM336-2.5: 0°C to +70°C
• Storage Temperature Range: -65°C to +150°C
• Maximum Power Dissipation: 500mW (TO-92), 800mW (TO-46), 500mW (SO)
• Maximum Forward Current: 10mA

Typical Electrical Performance

• Reference Voltage (V_REF): 2.5V ±1%
• Dynamic Impedance (Z_ZT): 0.2Ω (typical)
• Temperature Coefficient (TC): Adjustable via third terminal; typically 30ppm/°C
• Operating Current Range: 400µA to 10mA
• Line Regulation: 0.05%/V (typical)
• Load Regulation: 0.1%/mA (typical)

Package Information

The LM136-2.5 series is available in multiple package options to suit various design requirements:

TO-92 Plastic Package (Z03A)

• Order Numbers: LM236Z-2.5, LM236AZ-2.5, LM336Z-2.5, LM336BZ-2.5
• Package Dimensions: 4.7mm x 3.7mm x 4.2mm
• Pin Configuration (Bottom View):
  • Pin 1: Anode
  • Pin 2: Adjust (for LM136-2.5)
  • Pin 3: Cathode

TO-46 Metal Can Package (H03H)

• Order Numbers: LM136H-2.5, LM136H-2.5/883, LM236H-2.5, LM136AH-2.5, LM136AH-2.5/883, LM236AH-2.5
• Package Dimensions: 5.2mm diameter, 5.3mm height
• Pin Configuration (Bottom View):
  • Pin 1: Anode
  • Pin 2: Adjust (for LM136-2.5)
  • Pin 3: Cathode

SO Package (M08A)

• Order Numbers: LM236M-2.5, LM236AM-2.5, LM336M-2.5, LM336BM-2.5
• Package Dimensions: 4.9mm x 3.9mm x 1.5mm
• Pin Configuration (Top View):
  • Pin 1: Anode
  • Pin 2: Adjust (for LM136-2.5)
  • Pin 3: Cathode
  • Pins 4-8: No Connection

Typical Applications

Basic 2.5V Reference Circuit

The simplest application of the LM136-2.5 is as a standalone 2.5V reference. Connect the cathode to a positive supply through a current-limiting resistor, and the anode to ground. The adjust pin (if present) can be left open or connected to a trimmer for fine-tuning.

Minimum Temperature Coefficient Configuration

For applications requiring the lowest possible temperature drift, connect a trimmer potentiometer between the adjust pin and ground. By adjusting this potentiometer, the temperature coefficient can be minimized for the specific operating conditions.

Wide Input Range Reference

When operating with input voltages significantly higher than 2.5V, use a series resistor to limit current through the device. The wide operating current range (400µA to 10mA) allows for flexibility in choosing the resistor value while maintaining stable regulation.