We Support Your Product Development by Easy Board Design and Advanced Sensing.
Our AFE products feature low power consumption and high-precision signal processing and correspond to a wide variety of sensor applications. Our proprietary technology provides high noise immunity and excellent linearity, enabling faithful reproduction of sensor signals. In addition, the small package enables space-saving mounting, making it ideal for portable devices and IoT equipment.
NA2202 / NA2203 / NA2204
5V Analog Front Ends with High-precision Delta Sigma A-D Converter
Product Lineup
The NA2202/2203/2204 are high-precision AFEs with up to 128 times internal programmable gain amplifiers (PGAs) and multiplexers built-in. They allow flexible connection of multiple sensors and reduce man-hours required for constant setting. 5 V operating voltage is supported, making it an ideal choice for systems using microcontrollers.
Furthermore, the compact package size of 4.0 x 4.0 x 0.75 mm contributes to product miniaturization. They are ideal for applications requiring high accuracy and space saving.
Product | Operating Temperature Range | Supply Voltage | ADC Resolution | Digital Calibration | PGA | Package |
NA2202 | -40°C to +125° |
Analog: +2.7 to +5.5V(Unipolar)or ±2.5V(Bipolar) Digital: +2.7 to +5.5V |
16 | Vos, Gain | 128V/V |
QFN4040-24-NB 4.0x4.0x0.75(mm) (Pitch: 0.5mm) pin-compatible |
NA2203 | 20 | |||||
NA2204 | 24 |
The internal 4-channel multiplexers enable detecting various multiple sensor signals.
Circuit example with temperature sensors connected to 3 channels

Applying a small package QFN4040-24-NB (4mm square) contributes to achieving smaller size of the board set and mounting area.
-
- QFN4040-24-NB 4.0x4.0x0.75(mm)(Pitch: 0.5mm)
- Since the NA2202 / NA2203 / NA2204 series are pin-compatible with each other, you can try each AFE with different ADC resolution for a same board to find the best one.
The disconnection detection function for such as sensors reduces the risk of false detection.
-
- When there is no disconnection
- IBURN does not flow to 100kΩ
- Thermoelectromotive force of type K thermocouple:
VIN1P - VIN1N = -(a few mV) to +(a few mV)
- ADC output is within normal range
-
- When there is a disconnection
- IBURN flows to 100kΩ
- VIN1P=AVDD-10µA*100kΩ=4V
VIN1N=AVSS+10µA*100kΩ=1V
VIN1P-VIN1N=3V - ADC output sticks to full scale so disconnection can be detected
Product Details
NJU9101
Low Power Analog Front End
Product Lineup
The NJU9101 integrates low power operational amplifiers, an A/D converter, and a signal processing circuit into one chip, enabling smaller applications and low power consumption. The internal operational amplifiers achieve low power consumption, high precision and low noise at the same time by our circuit and process technology. Also, it contains a newly designed low-current A/D converter.
Functions include gain, offset and temperature drift calibration. They are easily adjustable from an MCU, which makes the NJU9101 helpful to shorten development period of gas monitors and create product series.
Product | Operating Temperature Range | Supply Voltage | ADC Resolution | Operating Current | Digital Calibration | Package |
NJU9101 | -40℃ to +85℃ | +2.4V to +3.6V | 16-Bit (NFB), 32sps to 2k sps | 4μA (OPA,OPB), 150μA (ADC) | Vos, Gain | EQFN-24-LE (4mmx4mm) |
High Precision, Low Noise and Low Current Consumption (about 5.0 µA), prolonging operating time of battery-powered systems
The NJU9101 not only has low power operational amplifiers and an A/D converter, but it can perform intermittent ON/OFF operation of each function block.
The standby current is as low as around 0.5 µA, which makes the NJU9101 suitable for battery powered systems.
High RF Noise Immunity against External Noise from such as Transceivers
The NJU9101 contains operational amplifiers with high RF noise immunity achieved by our analog circuit technology.
They prevent the AFE from malfunctioning caused by electric waves emitted from transceivers.
Containing Functions Effective for Gas Detection
The 3-bit chip address allows for detecting maximum 7 types of gas with a single detector.
It can check sensor connection status thanks to the sensor diagnostic function.
Connecting an external EEPROM enables automatical setup of the AFE according to the memory at its startup.
Combining the following circuit blocks makes the NJU9101 usable for various low consumption power signal applications.
1. Temperature Sensor Measurement
Write below code to measure Temperature.
-
-
NJU9101 Circuit Block Name
CIRCUIT BLOCK NAME SYMBOL 2 Low Current Operational Amplifiers "OPA", "OPB" Bias Level Setting Register "BIASRES" 100Ω Analog Switch "ANASW" Variable Gain Pre-Amplifier "PREAMP" Temperature Sensor "TempSensor" Internal Reference "INTVREF (2.048V)" 16-Bit sigma delta ADC "16-Bit ADC" Digital Control & Calibration "Control & Calibration" I2C Bus Compatible Control "I2C"
No. | CONTENTS | REGISTER ADDRESS | REGISTER NAME | BIT NAME | BIT | VALUE |
---|---|---|---|---|---|---|
1 | Select Temperature Input Mode | 0x00 | CTRL | MEAS_SEL | [2:1] | 00 |
2 | Select ADC Conversion Mode (Exp. Single Conversion) | MEAS_SC | [0] | 0 | ||
3 | Start AD Conversion | MEAS | [3] | 1 | ||
4 | Check completion of the AD conversion ('MEAS' bit = '0') | - | ||||
5 | Acquire AD conversion data (TMPDATA) | 0x06 0x07 |
TMPDATA0 TMPDATA1 |
TMPDATA | [9:0] | - |
2. System Example 1 (Potentiostat Measurement)
Write below code to constitute "potentiostat" and "trans-impedance amplifier."
No. | CONTENTS | REGISTER ADDRESS | REGISTER NAME | BIT NAME | BIT | VALUE |
---|---|---|---|---|---|---|
1 | Connect the switch 'BIASRES' and 'OPA' | 0x0F | BLKCONN0 | BIASSWA | [5] | 1 |
2 | Connect the switch 'BIASRES' and 'OPB' | BIASSWB | [4] | 1 | ||
3 | Select output of BIASRES | 0x11 | BLKCONN2 | BIASSWN | [3] | 1 |
4 | Bias level for 'trans-impedance amplifier' (GND to 1.7V) | 0x10 | BLKCONN1 | OPA_BIAS | [7:5] | any |
5 | Bias level for 'potentiostat' (GND to 1.75V) | OPB_BIAS | [4:0] | any | ||
6 | Powered on BIASRES, OPA, OPB, OSC | 0x12 | BLKCTRL | BLKCTRL | [7:0] | 0xF0 |
7 | Enable PREAMP | 0x11 | BLKCONN2 | PAMPSEL | [2] | 1 |
8 | Select Amp Input Mode | 0x00 | CTRL | MEAS_SEL | [2:1] | 01 |
9 | Set Measurement Mode for ADC (ex. Single conversion) | MEAS_SC | [0] | 0 | ||
10 | Start measurement | MEAS | [3] | 1 | ||
11 | Check completion of the AD conversion ('MEAS' bit = '0') | - | ||||
12 | Acquire AD conversion data (AMPDATA) | 0x02 0x03 |
AMPDATA0 AMPDATA1 |
AMPDATA | [15:0] | - |
3. System Example 2 (Differential Input)
Write below code to constitute "Differential Amplifier Input" by using OPA/OPB.
No. | CONTENTS | REGISTER ADDRESS | REGISTER NAME | BIT NAME | BIT | VALUE |
---|---|---|---|---|---|---|
1 | Open OPA input switch | 0x0F | BLKCONN0 | BIASSWA | [5] | 0 |
2 | Open OPB input switch | BIASSWB | [4] | 0 | ||
3 | Select OPA sensor signal input | 0x11 | BLKCONN2 | INPSWA | [5] | 1 |
4 | Select OPB sensor signal input | INPSWB | [4] | 1 | ||
5 | Select OPB output | BIASSWN | [3] | 0 | ||
6 | Powered on OPA, OPB, OSC | 0x12 | BLKCTRL | BLKCTRL | [7:0] | 0x70 |
7 | Enable PREAMP | 0x11 | BLKCONN2 | PAMPSEL | [2] | 1 |
8 | Select Amp Input Mode | 0x00 | CTRL | MEAS_SEL | [2:1] | 01 |
9 | Set Measurement Mode for ADC (ex. Single conversion) | MEAS_SC | [0] | 0 | ||
10 | Start measurement | MEAS | [3] | 1 | ||
11 | Check completion of the AD conversion ('MEAS' bit = '0') | - | ||||
12 | Acquire AD conversion data (AMPDATA) | 0x02 0x03 |
AMPDATA0 AMPDATA1 |
AMPDATA | [15:0] | - |
4. System Example 3 (Single Input (Non-Inverting))
Write below code to constitute "Single Amplifier Input" by using OPA/OPB.
No. | CONTENTS | REGISTER ADDRESS | REGISTER NAME | BIT NAME | BIT | VALUE |
---|---|---|---|---|---|---|
1 | Open OPA input switch | 0x0F | BLKCONN0 | BIASSWA | [5] | 0 |
2 | Close OPB input switch | BIASSWB | [4] | 1 | ||
3 | Select OPA sensor signal input | 0x11 | BLKCONN2 | INPSWA | [6] | 1 |
4 | Connect OPB positive input to GND | INPSWB | [5] | 0 | ||
5 | Select BIASRES output | BIASSWN | [3] | 1 | ||
6 | Powered on BIASRES, OPA, OPB, OSC | 0x12 | BLKCTRL | BLKCTRL | [7:0] | 0xF0 |
7 | Enable PREAMP | 0x11 | BLKCONN2 | PAMPSEL | [2] | 1 |
8 | Select Amp Input Mode | 0x00 | CTRL | MEAS_SEL | [2:1] | 01 |
9 | Set Measurement Mode for ADC (ex. Single conversion) | MEAS_SC | [0] | 0 | ||
10 | Start measurement | MEAS | [3] | 1 | ||
11 | Check completion of the AD conversion ('MEAS' bit = '0') | - | ||||
12 | Acquire AD conversion data (AMPDATA) | 0x02 0x03 |
AMPDATA0 AMPDATA1 |
AMPDATA | [15:0] | - |
5. Auxiliary (external Input) Measurement
Write below code to constitute "Differential Amplifier Input" by using PREAMP.
No. | CONTENTS | REGISTER ADDRESS | REGISTER NAME | BIT NAME | BIT | VALUE |
---|---|---|---|---|---|---|
1 | Select AUXIN input | 0x11 | BLKCONN2 | BIASSWN | [3] | 1 |
2 | Enable PREAMP | PAMPSEL | [2] | 1 | ||
3 | Select Auxiliary input mode | 0x00 | CTRL | MEAS_SEL | [2:1] | 10 |
4 | Set Measurement Mode for ADC (ex. Single conversion) | MEAS_SC | [0] | 0 | ||
5 | Start measurement | MEAS | [3] | 1 | ||
6 | Check completion of the AD conversion ('MEAS' bit = '0') | - | ||||
7 | Acquire AD conversion data (AUXDATA) | 0x02 0x03 |
AMPDATA0 AMPDATA1 |
AMPDATA | [15:0] | - |
Product Details
NA2201 / NJU9102 / NJU9102A
Digital Earth Leakage Current Detector IC, or Ground Fault Current Detect IC
Product Lineup
The NA2201 / NJU9102 / NJU9102A are digital earth leakage current detector ICs for earth leakage current breakers. They convert analog signals obtained from a zero-phase-sequence current transformer into digital data via a built-in ADC, and process the current leakage data based on earth leakage current detector condition. As a result of data processing, they output a one-shot pulse from the SCRT terminal when an analog signal is judged to a leakage condition, and turns on an external thyristor.
Among these three AFEs, the NA2201 contains a overvoltage detection function and supports over voltage detection (neutral conductor open-phase protection).
Product | Operating Temperature Range | Supply Voltage | ADC Resolution | DC Current Detection Function | Time Delay Function | Package |
NA2201 | -40°C to +12°C | 4.0V to 5.5V | 14 | Available | 2 Systems (leakage / overvoltage) | SSOP-16-BD |
NJU9102 | Unavailable | Unavailable | DMP-8 | |||
NJU9102A |
NA2201 Digital Earth Leakage Current Detector IC, or Ground Fault Current Detect IC With Over Voltage Detection / DC Current Detection
The NA2201 is an excellent choice for industrial applications that require high reliability.
It has AC ground fault leakage current detection, open neutral detection and DC current detection functions. Also, for use in EV battery chargers, the NA2201 has DC current detection and 2-system time delay functions.
It has settings that the circuit designer can select for a particular application. It is ideal for applications that are noise sensitive because of its internal sinc3 filtering.
-
NA2201 Block Diagram (Overvoltage Detection)
-
NA2201 Block Diagram (DC Current Detection)
NJU9102 / NJU9102A Digital Earth Leakage Current Detector IC, or Ground Fault Current Detect IC
-
- The internal digital filter (LPF) can cut line noise and common noise, contributing to reducing the risk of malfunction.
No need to add an active filter, so these ICs can help you reduce number of parts, evaluation man-hours and cost. - You can select whether or not the IC has five times trip level immediate detection according to your applications.
- Configuring the earth leakage detector condition pin (TMD) makes it possible to choose Type A or Type AC.
- The internal digital filter (LPF) can cut line noise and common noise, contributing to reducing the risk of malfunction.
-