CA3130E CMOS Operational Amplifier

Overview

The CA3130E is a high-performance CMOS operational amplifier that combines the advantages of both CMOS and bipolar technologies. It features a MOSFET input stage, enabling extremely high input impedance and low input bias current, making it ideal for applications requiring minimal loading on signal sources. The device is designed for single-supply operation, with an input common-mode range that includes the negative supply rail and an output stage capable of swinging close to both supply rails.

Key to its versatility is the strobe function (Terminal 8), which allows the output stage to be forced into a high-impedance state, effectively turning the amplifier "OFF" when connected to the negative supply rail. This feature is particularly useful in multiplexing applications or power-saving scenarios.

Features

• MOSFET Input Stage Provides:
  • Very High Input Impedance: Z_I = 1.5 TΩ (1.5 × 10¹²Ω) (Typical)
  • Very Low Input Bias Current:
    • 5pA (Typ) at 15V Operation
    • 2pA (Typ) at 5V Operation
• Ideal for Single-Supply Applications
• Common-Mode Input-Voltage Range Includes Negative Supply Rail
• Input Terminals Can Be Swung 0.5V Below Negative Supply Rail
• CMOS Output Stage Permits Signal Swing to Either (or Both) Supply Rails
• Strobe Capability for Output Stage Quiescence
• Wide Supply Voltage Range: 5V to 16V
• Low Power Consumption: 10mW (Typ) at ±7.5V Supply

Applications

The CA3130E's unique combination of characteristics makes it suitable for a wide range of applications, including:

• Sample-and-Hold Circuits
• Peak Detectors
• Long-Duration Timers/Monostables
• Photocell Amplifiers
• High-Input-Impedance Buffers
• CMOS Logic Interface Circuits
• Voltage Followers
• Signal Conditioning for High-Impedance Sensors
• Portable and Battery-Powered Equipment
• Medical Instrumentation

Electrical Characteristics

The following table summarizes key electrical characteristics at T_A = 25°C, V⁺ = 15V, V^- = -7.5V unless otherwise specified.

DC Characteristics

• Input Offset Voltage: 2mV (Max)
• Input Bias Current: 5pA (Typ), 50pA (Max)
• Input Offset Current: 0.5pA (Typ), 25pA (Max)
• Input Resistance: 1.5TΩ (Typ)
• Large-Signal Voltage Gain: 50V/mV (Min) at R_L = 2kΩ
• Supply Current: 4mA (Typ), 6mA (Max)

AC Characteristics

• Gain-Bandwidth Product: 15MHz (Typ)
• Slew Rate: 10V/μs (Typ)
• Rise Time: 100ns (Typ)
• Overshoot: 10% (Typ)

Strobe Characteristics

• Strobe Input Current: 1μA (Max)
• Output Leakage Current (Strobed OFF): 1nA (Max)
• Strobe Turn-ON Time: 1μs (Typ)
• Strobe Turn-OFF Time: 1μs (Typ)

Package Information

The CA3130E is available in several package options:

8-Pin DIP (Dual In-Line Package)

• Package Code: E (CA3130E)
• Dimensions: 9.81mm × 6.35mm × 3.3mm
• Pin Spacing: 2.54mm (0.1") between pins
• Row Spacing: 7.62mm (0.3") between rows
• Material: Molded Plastic
• Operating Temperature Range: -55°C to +125°C

8-Pin SOIC (Small Outline Integrated Circuit)

• Package Code: M (CA3130M)
• Dimensions: 4.9mm × 3.9mm × 1.25mm
• Pin Spacing: 1.27mm (0.05") between pins
• Material: Molded Plastic
• Operating Temperature Range: -55°C to +125°C

Pin Configuration

The 8-pin configuration is as follows:

• Pin 1: Offset Null
• Pin 2: Inverting Input (-)
• Pin 3: Non-Inverting Input (+)
• Pin 4: Negative Supply (V^-)
• Pin 5: Offset Null
• Pin 6: Output
• Pin 7: Positive Supply (V⁺)
• Pin 8: Strobe

Design Considerations

When designing with the CA3130E, consider the following:

• For optimal performance, keep supply leads as short as possible and bypass with 0.1μF capacitors close to the device
• The strobe function (Pin 8) should be left open or connected to V⁺ for normal operation
• When using the offset null capability (Pins 1 and 5), use a 10kΩ potentiometer between these pins with the wiper connected to V^-
• For unity-gain applications, consider adding a small compensation capacitor (5-10pF) between Pin 6 (Output) and Pin 2 (Inverting Input) to prevent oscillation
• The device is sensitive to electrostatic discharge (ESD); proper ESD precautions should be observed during handling and assembly

Conclusion

The CA3130E CMOS operational amplifier offers a unique combination of high input impedance, low power consumption, and rail-to-rail output capability that makes it particularly suitable for interfacing with high-impedance sensors and single-supply applications. Its strobe function adds flexibility for multiplexed systems or power-saving designs. With performance characteristics that bridge the gap between bipolar and CMOS technologies, the CA