OPA2277UA/2K5

The Texas Instruments OPA2277UA/2K5 is a dual-channel precision operational amplifier that replaces the industry-standard OP-177. The OPAx277 series offers improved noise performance, wider output voltage swing, and twice the speed with half the quiescent current of its predecessors. With ultra-low offset voltage of 10uV and drift of +-0.1uV/C, the device ensures accuracy in precision applications. The 140dB CMRR and 130dB PSRR provide excellent rejection of power supply and common-mode interference. The device operates from +-2V to +-18V supplies with 800uA/amplifier quiescent current. Dual channels feature completely independent circuitry for lowest crosstalk.

The OPA2277UA/2K5 operates as a precision voltage-feedback operational amplifier with three key design elements: 1) Input Stage: A super-beta bipolar input pair with laser-trimmed offset resistors achieves 10uV typical offset voltage and 1nA max bias current. The balanced input architecture provides 140dB CMRR. 2) Gain Stage: The high-gain internal voltage amplifier provides 134dB open-loop gain, ensuring minimal gain error in closed-loop configurations. The internal compensation network ensures unity-gain stability with capacitive loads. 3) Output Stage: A Class AB output stage swings within 1V of the supply rails (RL=10kOhm) with 0.8V/us slew rate and 1MHz gain-bandwidth product. The dual channels use independent circuitry to prevent crosstalk even during overload conditions.

• Precision weigh scale and strain gauge signal conditioning
• Medical instrumentation (ECG, EEG amplifiers)
• Industrial 4-20mA transmitter signal chains