LM139

LM139 Quad Independent Precision Voltage Comparator

Overview

The LM139 series is a quad independent precision voltage comparator designed for reliable operation across a wide range of supply voltages. This component is optimized for single-supply applications but also supports split-supply configurations. With a maximum offset voltage of just 2 mV across all four comparators, the LM139 ensures high accuracy in signal comparison tasks. Its input common-mode range includes ground, making it suitable for low-voltage and single-supply applications.

Key Features

• Quad Independent Comparators: Four precision voltage comparators in a single package.
• Wide Supply Voltage Range: Operates from 2 VDC to 36 VDC, supporting both single and dual supply configurations.
• Low Input Offset Voltage: Maximum offset voltage of 2 mV ensures high accuracy.
• Ground-Included Common-Mode Range: Inputs can operate at or near ground potential, even with a single power supply.
• Low Power Consumption: Supply current drain remains low and stable regardless of supply voltage magnitude.
• High Stability: Designed for minimal performance variation over temperature and supply voltage fluctuations.

Applications

The LM139 is versatile and finds use in a broad range of applications, including:

• Voltage Monitoring: Overvoltage and undervoltage detection in power supplies.
• Signal Conditioning: Level shifting and window comparison in analog circuits.
• Oscillators and Timers: Precision timing applications requiring stable comparator operation.
• Industrial Control Systems: Threshold detection in automation and control circuits.
• Battery-Powered Devices: Low-voltage operation makes it ideal for portable electronics.
• Automotive Electronics: Robust performance suits it for automotive sensing and control.

Electrical Characteristics

The following table summarizes the key electrical specifications of the LM139:

• Supply Voltage Range: 2 VDC to 36 VDC
• Input Offset Voltage (Max): 2 mV
• Input Bias Current (Typical): 25 nA
• Response Time (Typical): 1.3 μs (for 5 mV overdrive)
• Common-Mode Input Voltage Range: 0 V to (V_CC - 1.5 V)
• Power Supply Current (Per Comparator): 0.8 mA (typical at 5 V)
• Output Sink Current: 6 mA (minimum)
• Operating Temperature Range: -25°C to +85°C (industrial grade)

Package Information

The LM139 is available in multiple package options to suit different PCB layouts and thermal requirements:

• 14-Pin PDIP (Plastic Dual In-Line Package):
  • Dimensions: 19.3 mm x 6.35 mm
  • Pin spacing: 2.54 mm (standard DIP pitch)
  • Thermal resistance: 80°C/W (typical)
• 14-Pin SOIC (Small Outline Integrated Circuit):
  • Dimensions: 8.65 mm x 3.9 mm
  • Pin spacing: 1.27 mm
  • Thermal resistance: 160°C/W (typical)
• 14-Pin TSSOP (Thin Shrink Small Outline Package):
  • Dimensions: 5 mm x 4.4 mm
  • Pin spacing: 0.65 mm
  • Thermal resistance: 240°C/W (typical)

Detailed Functional Description

The LM139 integrates four independent voltage comparators that can operate from a single power supply as low as 2V up to 36V. Each comparator features a differential input stage that allows the device to compare two analog voltage signals and produce a digital output indicating which input is higher. The open-collector output stage provides flexibility in interfacing with various logic families or driving indicator devices.

Key operational aspects include:

• Input Stage: The differential input pairs are designed to minimize offset voltage and temperature drift while maintaining high input impedance.
• Output Stage: Open-collector configuration allows for wired-OR connections and easy interface with different logic levels.
• Power Supply Considerations: The device maintains stable operation across the entire supply range with minimal current variation.

Design Considerations

When implementing the LM139 in circuit designs, several factors should be considered:

• Power Supply Decoupling: A 0.1 μF ceramic capacitor should be placed close to the power supply pins to minimize noise.
• Output Pull-Up Resistors: Appropriate resistors should be selected based on the desired output current and voltage levels.
• Thermal Management: In high-temperature environments or when driving heavy loads, consider the package's thermal characteristics.
• PCB Layout: Keep input traces short and properly shielded to prevent noise pickup in sensitive applications.

Reliability and Qualification

The LM139 is designed and tested to meet stringent quality and reliability standards:

• ESD protection on all pins (typically 1 kV HBM)
• Industrial temperature range operation (-25°C to +85°C)
• Manufactured in facilities certified to ISO 9001 standards
• RoHS compliant versions available

Ordering Information

The device is available in several package variants with different temperature ranges:

• LM139N: 14-pin PDIP, industrial temperature range
• LM139D: 14-pin SOIC, industrial temperature range
• LM139PW: 14-pin TSSOP, industrial temperature range