OP495 Quad CBCMOS Operational Amplifier

Overview

The OP495 is a quad CBCMOS operational amplifier that combines rail-to-rail output swing with exceptional DC accuracy. Designed with a bipolar front end, it achieves lower noise and higher accuracy compared to traditional CMOS designs. The device supports both input and output ranges that include the negative supply, enabling "zero-in/zero-out" functionality. This makes it particularly suitable for 3.3V systems, such as those powered by lithium batteries.

Key Features

• Rail-to-Rail Output Swing: Ensures maximum dynamic range in single-supply applications.
• Single-Supply Operation: Supports a wide voltage range from +3V to +36V.
• Low Offset Voltage: 300μV maximum for high precision applications.
• Gain Bandwidth Product: 75kHz for stable performance in signal conditioning circuits.
• High Open-Loop Gain: 1000V/mV ensures accurate amplification.
• Unity-Gain Stable: No external compensation required for stable operation.
• Low Supply Current: 150μA per amplifier (max) for energy-efficient designs.

Applications

The OP495 is designed for a variety of precision and low-power applications, including:

• Battery-Operated Instrumentation: Ideal for portable devices due to low power consumption.
• Servo Amplifiers: Provides accurate control in motor drive systems.
• Actuator Drives: Ensures precise movement control in industrial applications.
• Sensor Conditioners: Amplifies weak sensor signals with minimal noise.
• Power Supply Control: Enhances regulation accuracy in DC-DC converters.

Electrical Characteristics

Absolute Maximum Ratings

• Supply Voltage (V_S): +36V
• Input Voltage Range: (V_EE - 0.3V) to (V_CC + 0.3V)
• Output Short-Circuit Duration: Indefinite (to ground, one amplifier at a time)
• Operating Temperature Range: -40°C to +85°C
• Storage Temperature Range: -65°C to +150°C

Typical Performance Specifications (V_S = +5V, T_A = 25°C)

• Input Offset Voltage: 150μV (typ), 300μV (max)
• Input Bias Current: 20nA (typ)
• Input Offset Current: 5nA (typ)
• Common-Mode Rejection Ratio (CMRR): 90dB (typ)
• Supply Voltage Rejection Ratio (SVRR): 90dB (typ)
• Large-Signal Voltage Gain: 1000V/mV (typ) at R_L = 10kΩ
• Output Voltage Swing: Rail-to-rail (within 10mV of supply rails)
• Quiescent Current (per amplifier): 120μA (typ), 150μA (max)

Package Information

Available Packages

• 14-Lead PDIP (Plastic Dual In-Line Package): Industry-standard through-hole package for prototyping and general use.
• 14-Lead SOIC (Small Outline Integrated Circuit): Surface-mount package for space-constrained applications.
• 16-Lead TSSOP (Thin Shrink Small Outline Package): Ultra-compact option for high-density PCB designs.

Package Dimensions

• PDIP: 19.30mm x 6.35mm (body), 2.54mm lead pitch.
• SOIC: 8.65mm x 3.90mm (body), 1.27mm lead pitch.
• TSSOP: 5.00mm x 4.40mm (body), 0.65mm lead pitch.

Thermal Characteristics

• Thermal Resistance (θ_JA):
  • PDIP: 70°C/W
  • SOIC: 160°C/W
  • TSSOP: 200°C/W
• Maximum Junction Temperature (T_J): +150°C

Design Considerations

PCB Layout Guidelines

To maximize performance, follow these PCB layout recommendations:

• Use a ground plane to minimize noise and improve thermal dissipation.
• Place decoupling capacitors (0.1μF ceramic) as close as possible to the supply pins.
• Avoid routing high-frequency signals near the amplifier inputs to prevent coupling.
• For sensitive applications, use shielded cables or guard rings around input traces.

Stability and Compensation

The OP495 is unity-gain stable and does not require external compensation. However, for capacitive loads >100pF, a small series resistor (10Ω to 100Ω) at the output is recommended to prevent oscillation.

Conclusion

The OP495 quad operational amplifier delivers precision, low-power operation, and rail-to-rail performance in a versatile package. Its combination of bipolar and CMOS technologies provides superior noise performance and DC accuracy, making it an excellent choice for battery-powered and precision analog applications. With multiple package options and robust electrical characteristics, the OP495 is well-suited for a wide range of industrial, automotive, and consumer electronics designs.