OPA177 Precision Operational Amplifier Technical Summary

OPA177 Precision Operational Amplifier

Overview

The OPA177 is a high-precision bipolar operational amplifier designed for applications requiring exceptional accuracy and stability. It offers ultra-low offset voltage, minimal drift over temperature, and high open-loop gain, making it an ideal choice for precision instrumentation, data acquisition, and other demanding analog signal processing tasks. The OPA177 serves as a direct replacement for legacy precision op-amps such as the OP-07, OP-77, OP-177, and AD707, while providing improved performance characteristics.

Key Features

Ultra-Low Offset Voltage: 25µV maximum ensures minimal DC error in precision applications
Exceptional Temperature Stability: Low drift of 0.3µV/°C maintains accuracy across operating temperatures
High Open-Loop Gain: 130dB minimum provides excellent signal integrity
Low Power Consumption: Quiescent current of 1.5mA typical for power-sensitive designs
Industry-Standard Replacement: Direct upgrade path for OP-07, OP-77, OP-177, and AD707 amplifiers
Internal Compensation: Stable without external components
Wide Supply Range: Operates from ±5V to ±18V supplies

Applications

The OPA177's precision characteristics make it suitable for a wide range of demanding analog applications:

Precision Instrumentation: High-accuracy measurement systems
Data Acquisition Systems: Front-end signal conditioning
Test Equipment: Precision voltage references and signal sources
Bridge Amplifiers: Strain gauge and pressure sensor interfaces
Thermocouple Amplifiers: Low-level temperature measurement
Medical Instrumentation: ECG and other biomedical signal processing
Industrial Process Control: High-accuracy feedback systems

Electrical Characteristics

The following specifications are typical at V_S = ±15V, T_A = 25°C unless otherwise noted:

DC Characteristics

Input Offset Voltage: 10µV typical, 25µV maximum
Input Offset Voltage Drift: 0.1µV/°C typical, 0.3µV/°C maximum
Input Bias Current: 1.5nA typical, 4nA maximum
Input Offset Current: 0.5nA typical, 1.5nA maximum
Open-Loop Voltage Gain: 140dB typical, 130dB minimum (R_L = 2kΩ)
Common-Mode Rejection Ratio: 130dB typical, 120dB minimum
Power Supply Rejection Ratio: 120dB typical, 110dB minimum

AC Characteristics

Gain Bandwidth Product: 1MHz typical
Slew Rate: 0.3V/µs typical
Settling Time to 0.01%: 10µs for 10V step
Input Voltage Noise: 0.1µV p-p (0.1Hz to 10Hz)
Input Current Noise: 0.1pA/√Hz at 1kHz

Power Characteristics

Supply Voltage Range: ±5V to ±18V
Quiescent Current: 1.5mA typical, 2.0mA maximum
Operating Temperature Range: -40°C to +85°C

Package Information

The OPA177 is available in multiple package options to suit various application requirements:

Standard Package Options

8-Pin PDIP (Plastic Dip):
- Package Code: P
- Dimensions: 9.81mm x 6.35mm
- Lead Pitch: 2.54mm
- Through-hole mounting
8-Pin SOIC (Small Outline IC):
- Package Code: D
- Dimensions: 4.90mm x 3.91mm
- Lead Pitch: 1.27mm
- Surface mount
TO-99 Metal Can:
- Package Code: H
- Dimensions: 9.08mm diameter
- 8-lead configuration
- Hermetically sealed

Pin Configuration (8-Pin Packages)

Pin 1: Offset Trim
Pin 2: Inverting Input (-IN)
Pin 3: Non-Inverting Input (+IN)
Pin 4: Negative Supply (V-)
Pin 5: Offset Trim
Pin 6: Output (OUT)
Pin 7: Positive Supply (V+)
Pin 8: NC (No Connection)

Design Considerations

Offset Voltage Trimming

The OPA177 includes dedicated trim pins (1 and 5) for nulling any residual offset voltage. For most applications, a 10kΩ potentiometer connected between these pins with the wiper to V+ provides adequate adjustment range. The trim network should use precision resistors to maintain stability.