LM3900 Quad Norton Operational Amplifier

Overview

The LM3900 is a quad Norton operational amplifier belonging to the LM2900 series, designed for single-supply voltage operation with a wide range of applications. It consists of four independent, dual-input, internally compensated amplifiers optimized for large output voltage swings. The device utilizes a current mirror to achieve non-inverting input functionality, making it suitable for AC amplification, active filters, waveform generation, and more.

Key advantages of the LM3900 include its ability to operate from a single power supply, low power consumption, and robust performance across a broad voltage range. Its architecture makes it particularly useful in low-frequency analog circuits where conventional op-amps may not perform optimally.

Features

• Wide Single-Supply Voltage Range: 4 VDC to 32 VDC, or dual supplies (±2 VDC to ±16 VDC).
• Low Power Consumption: Supply current drain is independent of supply voltage.
• Low Input Bias Current: 30 nA typical, reducing errors in high-impedance circuits.
• High Open-Loop Gain: 70 dB ensures accurate signal amplification.
• Wide Bandwidth: 2.5 MHz at unity gain for broad frequency response.
• Large Output Voltage Swing: Nearly rail-to-rail (V_CC - 1 V) peak-to-peak.
• Internal Frequency Compensation: Stable at unity gain without external components.
• Output Short-Circuit Protection: Enhanced durability in fault conditions.

Applications

The LM3900 is versatile and finds use in a variety of analog circuit designs, including:

• AC Amplifiers: Suitable for small-signal amplification in audio and instrumentation systems.
• RC Active Filters: Can be used to implement low-pass, high-pass, and band-pass filters.
• Waveform Generation: Ideal for low-frequency triangle, square, and pulse wave circuits.
• Tachometers: Provides signal conditioning in speed measurement systems.
• Low-Frequency Signal Processing: Used in integrators, differentiators, and comparators.
• Transducer Interfaces: Amplifies signals from sensors in industrial and automotive applications.

Electrical Characteristics

Absolute Maximum Ratings

• Supply Voltage (V_CC): 32 VDC (single supply) or ±16 VDC (dual supply).
• Input Voltage Range: -0.3 V to V_CC + 0.3 V.
• Output Short-Circuit Duration: Indefinite (with proper heat dissipation).
• Operating Temperature Range: 0°C to +70°C (commercial), -55°C to +125°C (military).
• Storage Temperature Range: -65°C to +150°C.

Typical Performance Characteristics

• Input Offset Voltage: 2 mV (typical).
• Input Bias Current: 30 nA (typical).
• Open-Loop Voltage Gain: 70 dB (minimum).
• Unity Gain Bandwidth: 2.5 MHz.
• Slew Rate: 0.5 V/µs (typical).
• Common-Mode Rejection Ratio (CMRR): 70 dB.
• Power Supply Rejection Ratio (PSRR): 100 dB.

Package Information

The LM3900 is available in multiple package options to suit different assembly and thermal requirements:

• Dual-In-Line (DIP): 14-pin (N14A package).
• Small Outline (SOIC): 14-pin (M14A package).

Pin Configuration (Top View)

• Pin 1: Output 1
• Pin 2: Inverting Input 1
• Pin 3: Non-Inverting Input 1
• Pin 4: V_CC+
• Pin 5: Non-Inverting Input 2
• Pin 6: Inverting Input 2
• Pin 7: Output 2
• Pin 8: Output 3
• Pin 9: Inverting Input 3
• Pin 10: Non-Inverting Input 3
• Pin 11: Ground (V_CC-)
• Pin 12: Non-Inverting Input 4
• Pin 13: Inverting Input 4
• Pin 14: Output 4

Thermal and Mechanical Specifications

• Thermal Resistance (θ_JA): 100°C/W (DIP), 160°C/W (SOIC).
• Maximum Junction Temperature (T_J): 150°C.
• Lead Soldering Temperature: 260°C for 10 seconds.

Conclusion

The LM3900 is a highly reliable and flexible quad operational amplifier designed for single-supply operation. Its combination of wide voltage range, low power consumption, and robust performance makes it an excellent choice for a variety of analog circuit applications. Whether used in active filters, waveform generators, or transducer interfaces, the LM3900 delivers consistent performance with minimal external components.