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Low Noise, Low Input Offset Voltage CMOS Operational Amplifier - LMR1802G-LB

LMR1802G-LB precision single CMOS operational amplifier features low noise, low input offset voltage and low input bias current that are suitable for equipment operating from battery power and using sensors that an amplifier.

The LMR1802G-LB, developed utilizing ROHM’s market-leading analog technology covering circuit design, processes, and layout, reduces input equivalent noise voltage density by half (2.9nV/√Hz at 1kHz, 7.8nV/√Hz at 10Hz) compared to conventional products, significantly improving the detection performance of sensor signals. In addition, best-in-class phase margin (68°) and capacitive load tolerance (500pF) provide excellent stability (difficult to oscillate, easy to handle).

※ ROHM July 2018 study

Key Features

Easy to use despite low noise results in the industry’s best performing CMOS op-amps

This latest product combines ROHM’s superior analog technology covering circuit design (new circuit at the differential input stage), layout (analog design cultivated over many years), and processes (optimized for low noise) to achieve ultra-low-noise. The input equivalent noise voltage density of 2.0nV/√Hz at 1kHz and 7.8nV/√Hz at 10Hz are approximately half that of products on the market, ensuring superior low-noise performance.

In addition, in the past when pursuing lower noise in op-amps there were problems such as poor phase margin and capacitive load characteristics, as well as oscillation that made circuit design difficult, but introducing a new circuit at the differential input stage allowed ROHM to achieve industry-low noise along with a class-leading phase margin of 68° and capacitive load tolerance of 500pF.

This doubles the detection capability of sensor signals over conventional solutions, enabling accurate amplification of voltages on the order of µV, improving performance with sensors that demand higher precision.

Op-Amp Comparison
CMOS Op-Amp Featuring Class-Leading Low Noise

Minimizes input offset voltage and input bias current

Minimizes Error Factors

In terms of op-amp configuration, the output voltage should be 0V when the input is 0V, but an offset voltage is often generated as an error. Also, if the sensor’s output impedance is high the sensor output voltage will be affected if the input bias current of the op-amp is large. Consequently, these two error factors must be made as small as possible to ensure optimal performance.

The LMR1802G-LB offers an input offset voltage of 450µV and input bias current of only 0.5pA (4x and 2x less than conventional products, respectively), providing high accuracy amplification.

Application Examples

  • Distance measuring equipment utilizing sonar and optical sensors
  • Security systems, IR remote controls, night vision, and other sets equipped with IR sensors
  • Devices demanding high accuracy operation (i.e. HDD)
  • Equipment management systems including flow meters and gas detectors
  • Other industrial and consumer sets integrating sensors requiring high accuracy detection

Terminology

CMOS (Complementary Metal Oxide Semiconductor)
Typically features smaller input current vs bipolar types, making it suitable for low-voltage operation.