LM258P - Dual Operational Amplifier

Overview

The LM258P is a dual operational amplifier (op-amp) designed for a wide range of analog applications. It consists of two independent, high-gain, frequency-compensated operational amplifiers that can operate from a single power supply or split power supplies. The device is optimized for low power consumption and stable operation across a broad voltage range, making it suitable for battery-powered and industrial applications.

Key advantages of the LM258P include its wide supply voltage range, low quiescent current, and compatibility with both single and dual supply configurations. These features make it a versatile choice for signal conditioning, filtering, and other analog circuit designs.

Features

• Dual Operational Amplifier: Contains two independent op-amps in a single package.
• Wide Supply Voltage Range: Operates from 3V to 30V (or ±1.5V to ±15V in split-supply mode).
• Low Power Consumption: Quiescent current is typically 0.7mA per amplifier.
• Frequency Compensation: Internal compensation ensures stability without external components.
• Large Output Voltage Swing: Capable of driving loads close to the supply rails.
• Low Input Bias Current: Typically 20nA, reducing errors in high-impedance circuits.
• Wide Temperature Range: Operates from -40°C to +85°C (industrial grade).
• ESD Protection: Built-in protection against electrostatic discharge.

Applications

The LM258P is used in a variety of analog and mixed-signal circuits, including:

• Signal Conditioning: Amplification and filtering of sensor signals.
• Active Filters: Low-pass, high-pass, and band-pass filter designs.
• Voltage Followers: Buffering high-impedance sources.
• Comparators: Simple threshold detection circuits.
• Oscillators: Wien bridge, phase-shift, and other oscillator topologies.
• Power Supply Control: Error amplification in voltage regulators.
• Battery-Powered Devices: Due to its low power consumption.

Electrical Characteristics

Absolute Maximum Ratings

• Supply Voltage (V_CC): 32V
• Differential Input Voltage: ±32V
• Input Voltage Range: -0.3V to V_CC + 0.3V
• Output Short-Circuit Duration: Continuous (with proper heat sinking)
• Operating Temperature Range: -40°C to +85°C
• Storage Temperature Range: -65°C to +150°C

Typical Performance Characteristics

• Input Offset Voltage: 2mV (typical), 7mV (maximum)
• Input Bias Current: 20nA (typical), 250nA (maximum)
• Input Offset Current: 3nA (typical), 50nA (maximum)
• Large-Signal Voltage Gain: 100V/mV (typical) at V_CC=15V, R_L=2kΩ
• Supply Current (per amplifier): 0.7mA (typical), 1.2mA (maximum)
• Output Voltage Swing: 0V to V_CC-1.5V (typical) with R_L=2kΩ
• Slew Rate: 0.3V/µs (typical)
• Gain Bandwidth Product: 1MHz (typical)

Package Information

The LM258P is available in an 8-pin PDIP (Plastic Dual In-line Package) with the following pin configuration:

• Pin 1: Output A
• Pin 2: Inverting Input A
• Pin 3: Non-Inverting Input A
• Pin 4: V_EE (Ground or Negative Supply)
• Pin 5: Non-Inverting Input B
• Pin 6: Inverting Input B
• Pin 7: Output B
• Pin 8: V_CC (Positive Supply)

Package Dimensions

• Package Type: PDIP-8
• Length: 9.81mm (max)
• Width: 6.35mm (max)
• Height: 3.3mm (max)
• Lead Pitch: 2.54mm

Design Considerations

Power Supply Decoupling

For optimal performance, it is recommended to place a 0.1µF ceramic capacitor close to the V_CC pin to reduce high-frequency noise. In split-supply applications, both positive and negative supply pins should be decoupled.

Input Protection

Although the LM258P has built-in ESD protection, additional input protection may be required in harsh environments. Series resistors or clamping diodes can be used to limit input current if the input voltage may exceed the supply rails.

Output Loading

The output stage can typically source or sink 20-30mA. For heavier loads, an external buffer may be required. The output swing is limited to approximately 1.5V from either supply rail under loaded conditions.

Alternative Parts

For applications with different requirements, consider these alternatives:

• LM358: Similar specifications but with improved input offset voltage.
• LM2904: Automotive-grade version with extended temperature range.
• TL082: Higher speed JFET-input op-amp for low-noise applications.
• MCP6002: Lower power CMOS alternative for battery applications.