Development Background and General Description

　With the evolution of IoT technology, various analog signals such as heat, sound, and light have been exchanged as digital information through the Internet. Therefore, Since the increasing number of IoT devices, energy saving of sensors is an important approach for the sustainable society. In recent years, IoT devices have often used for wireless communication such as Bluetooth® to send and receive signals, and electronic parts are required to operate stably against RF noise emitted from wireless devices.
　The NJU77212 has an extremely low supply current of 0.6uA/ch and is ideal for applications required ultra-low power. In addition, the industry-leading high EMI-immunity of 100 dB ensures stable operation even in a wireless communication environment.

NJU77212's Features

• 1.　Ultra-low supply current of 0.6uA/ch, low operating voltage of 1.7V, Rail-to-Rail input with Dynamic Transient Stabilizer ^TM
  • 　The NJU77212 is an ultra-low power comparator with a supply current of 0.6uA/ch.
    　The NJU77212 has a wide operating voltage range of 1.7V to 5.5V and is also compatible with 1.8V digital power supplies for low voltage applications. Due to Rail-to-Rail input function, the full range signal of 0V to 1.8V can be detected even with 1.8V power supply. The NJU77212 is equipped with our unique circuit technology Dynamic Transient Stabilizer TM that stabilizes the Rail-to-Rail input characteristics. This feature allows the comparator to keep a stable output response while the propagation delay time does not fluctuate much, even if the reference voltage Vref fluctuates (Refer to Figure 1). This feature is especially useful in applications with multiple reference voltage Vrefs, such as window comparators and level detectors (Refer to Figure 2).

What is Dynamic Transient Stabilizer ^TM (D.T.S)

　It is our original Rail-to-Rail input circuit technology, and the feature is that the response time does not fluctuate significantly even if the input reference voltage Vref fluctuates.

Figure 1　 Using NJU77212, the propagation delay time fluctuates very little even if the reference voltage Vref fluctuates

omparator circuit with multiple reference voltage Vrefs

Using a general comparator, the difference between Vo1 and Vo2 is large.

Using the NJU77212 with D.T.S., the difference of response between Vo1 and Vo2 is small

Figure 2　The NJU77212 keeps stable response characteristics even if Vref fluctuates, due to Dynamic Transient Stabilizer ^TM

• 2.　Industry-leading high EMI-immunity of 100dB contributes to reduction of equipment EMC design time and equipment miniaturization
  • 　The number of sensor devices controlled by wireless communication such as Bluetooth® is increasing. Such wireless communication uses a high frequency band in the GHz band.
    　The NJU77212 achieves the industry-leading high EMIRR ^*2 of 100 dB, while has an ultra-low power (Refer to Figure 4). This means that the input offset voltage fluctuates by only 1uV even if an electromagnetic wave of 100mVpk is injected to the input terminal of the comparator.
    　The high EMIRR of the NJU77212 can contribute to reduction of the EMC design time for sensor equipment. In addition, the capacitors and resistors required for EMC countermeasures previously are no longer needed, which can contribute to the equipment miniaturization

*2 EMIRR

If an electromagnetic signal source in the GHz band exists near the IC, the electromagnetic wave is rectified by the PN junction inside the IC, so that the output voltage of the comparator may cause malfunction with inversion (Refer to Figure 3). EMIRR (Electro Magnetic Interference Rejection Ratio) is an index showing the rejection to electromagnetic waves. This value is larger, the stronger rejection to electromagnetic waves, and it operates stably even in a wireless communication environment.

• 3.　High output current of 25mA can remove the rear stage driver and contribute to equipment miniaturization.
  • 　The NJU77212 has a large current capacity of 25mA, despite its ultra-low supply current of 0.6uA/ch. (Refer to Figure 5). This output capability can drive LEDs and relay switches directly, and reduce the number of driver parts required in the past. For example, the NJU77212 can contribute to the miniaturization of equipment for alarm applications that usually monitor as sensor with ultra-low power consumption and LED lights only in abnormal conditions (Refer to Figure 6).

Appearance

NJU77212R (MSOP8(VSP8))

NJU77212KU1 (DFN8-U1(ESON8-U1))

Characteristics]

• Ultra-low power: 0.6uA/ch typ. ： 0.6uA/ch typ.
• High EMIRR ： 100dB typ.(f=1.8GHz)
• Operating Voltage ： 1.7V to 5.5V
• Rail-to-Rail input with Dynamic Transient Stabilizer ^TM (D.T.S.)
• Output current ： 25mA typ.
• Input Overvoltage Protection (Input tolerant)
• Push-pull output
• Input Offset Voltage ： 7mV max.
• Propagation Delay Time ： 9.8us typ.(Rise) / 4.8us typ.(Fall)
• Operating Temperature ： -40ºC to 105ºC
• Package ：MSOP8(VSP8)(2.9mm×4.0mm) / DFN8-U1(ESON8-U1)(2.0mm×2.0mm)

Applications

• Wireless Communication Equipment
• Alarm and Monitoring System
• Battery-powered Remote Sensors
• Energy Harvesting Applications
• Wearable Devices

Production Schedule

• SamplesAlready started
• ProductionPlan to start from early 2022

【Click here for product details】
https://www.nisshinbo-microdevices.co.jp/en/products/comparator/spec/?product=nju77212

Ultra-low power comparator series

　Ultra-low power comparators are being developed in the series. The output will be Open-Drain and Push-Pull, and the number of circuits will be 1ch and 2ch. All types of samples are available.

Number of circuits	Part No.	Output type	Package	Status	Samples
1ch.	NJU77210	Push-Pull Output	SC88A SOT-23-5 DFN6-G1(ESON6-G1)	Under Development	Active
2ch.	NJU77212	Push-Pull Output	MSOP8(VSP8) DFN8-U1(ESON8-U1)	Under Development	Active
1ch.	NJU77220	Open-Drain Output	SC88A SOT-23-5 DFN6-G1(ESON6-G1)	Under Development	Active
2ch.	NJU77222	Open-Drain Output	MSOP8(VSP8) DFN8-U1(ESON8-U1)	Under Development	Active