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Press Release
June 14, 2022

- Solving technical challenges of high-speed sensors -

Start Production: the NJM2725, 160 MHz, 1.4 nV/√Hz, High Speed Operational Amplifier

Nisshinbo Micro Devices Inc. has started producing the NJM2725, a high-speed (160 MHz) and low noise (1.4 nV/√Hz) operational amplifier for high-speed sensors.

Overview

In recent years, technological innovations in national projects such as Society 5.0, Industry 4.0, and China Manufacturing 2025 have been progressing rapidly. In our daily lives, there are more situations in which robots are used to guide people in stores, drive cars automatically, and sort packages in warehouses.
In the background of these situations, lies widespread use of IoT, AI, and robotics, and sensors are behind the scenes supporting these technologies. Sensors convert external changes into electrical signals. One of the roles of an operational amplifier is amplifying these signals accurately to be processed appropriately.
The NJM2725 is an operational amplifier that combines high-speed performance of 160 MHz with low-noise performance of 1.4 nV/√Hz, which is ideal for ultrasonic sensors that monitor distance and material conditions without contact.

NJM2725

NJM2725 (MSOP8(VSP8) Package and SOP8 Package)

Features

1. Frequency performance of 160 MHz for ultrasonic sensors

Ultrasonic is a generic term of frequencies that are inaudible to human hearing. Ultrasonic can be used to monitor the conditions such as distance to an object and its thickness without contact. The NJM2725's frequency performance of GBW = 160 MHz provides high-speed amplification of signals from industrial sensors that use ultrasonic waves, such as proximity sensors, liquid level sensors, and double-feed detection sensors.

Frequency performance

2. Aiming to provide operational amplifiers with the highest signal-to-noise ratio (S/N ratio)

For high-speed sensors such as ultrasonic sensors, it is important not only to provide high speed but also low noise. The NJM2725 aims to reproduce the original signal of sensors accurately. As a result, the noise performance of 1.4 nV/√Hz, the lowest among our operational amplifier products, is achieved. This performance supports the original performance of sensors and provides higher reproducibility. The NJM2725 will contribute to the development of the sensor market, which is becoming faster and more sophisticated.

Output waveform comparison
Measurement Circuit

3. Designed for Single-supply Operation

In general, when considering battery-operated systems or the use of AD converters to capture sensor signals, operational amplifiers are often used with a single supply. The NJM2725 used with a single supply cannot handle signals near GND (0V) as a result of seeking the best high-speed and low-noise characteristics in our products. Normally, if a signal near GND is input to the operational amplifier having such characteristics, the output signal might be inverted, which is difficult to handle. Therefore, the NJM2725 has a built-in circuit that prevents output inversion when an input signal near the GND or power supply voltage is applied. It provides reliable and stable performance even when used in single-supply operation.

No phase inversion, just clip.

4. Optimal performance in combination

When considering a front-end signal chain, very small signals from sensors are amplified to 5 V by an operational amplifier, and then converted from analog to digital and processed digitally by a microcontroller or other device. In this case, if a single IC is used to operate everything from very small signals to just before digitization, this will be reflected in the cost of operational amplifiers.
Combining the NJM2725 and a high-speed rail-to-rail operational amplifier (e.g., NJU77582) will achieve a cost-effective high-performance sensor module. The NJM2725 specializes in amplifying small signals by taking advantage of its high speed and low noise, and rail-to-rail input/output operational amplifiers in the next stage specialize in coordinating signals with the microcontroller.

Example of amplifier for ultrasonic sensors

Specifications

(V+ = 5V, V- = 0V, Typical value)

GBW 160 MHz
Low Noise 1.4 nV/√Hz (f = 100kHz)
Input Offset Voltage 1 mV max
Supply Voltage 4 V to 10 V
Common-Mode Input Voltage Range 1.5 V to 3.8 V
High-level Output Voltage (RL = 1kΩ) 1.3 V to 3.5 V
Supply Current 4 mA/ch
Operating Temperature -40°C to 125°C
Slew Rate 15 V/µs
Stable Gain ≥ 2
Package MSOP8 (VSP8) (2.8 × 2.9 × 1.2 mm)
SOP8 (3.9 × 4.9 × 1.55 mm) *Under development

Applications

  • Low-noise Measurement Instrument
  • Ultrasonic Sensor
  • High-Speed Low-Noise Active Filter
  • ADC Buffer Amplifier
  • Sensor Interface

Reference Price

JPY 198 (Tax Included) per unit *

* When purchasing 1 reel, MSOP8 (VSP8) 2000 pcs/reel, SOP8 2500 pcs/reel
* Price is based on the consumption tax rate as of June 2022.

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