NJU72343 NJU72750/1A

In order to realize high quality sound, low distortion and low noise, now mainly use audio selector consisting of electronic volume and analog switch in audio equipment. These developed Electronic Volume NJU72343, Analog Switch NJU72750A and NJU72751A adopt the New JRC’s circuit design technology and semiconductor process technology of high quality sound, low distortion and low noise that have been cultivated so far. To improve the sound quality, it is necessary to change the sound processing quality of audio selector parts. The combination of these products can make audio equipment to achieve high quality sound, low distortion and low noise. Not only that, these products can be controlled by the same serial bus, so you can flexibly configure the number of input and output signals and the number of channels according to the needs of different systems.

Features

1. Realize high quality sound, low distortion and low noise NJU72343 is an electronic volume for high quality sound that considers low noise and THD (Total Harmonic Distortion) characteristic in high frequency. NJU72750A and NJU72751A are analog switches with low ON resistance that can reduce noise voltage and THD of audio equipment.

Conventional analog switch has a great ON resistance in audio selector. In order to prevent THD from increasing, an operational amplifier has been used after analog switch. Because NJU72750A and NJU72751A have low ON resistance, even if omit the operational amplifier, it is possible to achieve low distortion. Without the noise of the operational amplifier, audio equipment can more easily achieve high quality sound and low noise.

2. Flexible system extensibility We provide the product lineup considering extensibility that you can flexibly configure the number of input and output signals and the number of channels depending on the system configuration. Using address selection pin, you can control maximum 2 NJU72343 ICs, 4 NJU72750A ICs or 4 NJU72751A ICs by the same serial bus.

3. Original 2-wired serial bus interface These products adopt 2-wired serial bus interface control mode that is similar to I2C serial bus interface. This signal control mode removed the acknowledge signal (ACK). The acknowledge signal generates a few mA current flow to the ground, which has adverse impact on audio signal path in control mode. This original 2-wired serial bus interface can suppress the impact.
Moreover, conventional I2C serial bus interface used open-drain port. But this 2-wired serial bus interface is not restricted to the open-drain port.

Features and Characteristics

Table caption
	NJU72343	NJU72750A	NJU72751A
Functions	8ch. Electronic volume	7-input 3-output 2-circuit Analog switch	4-input 4-output 2-circuit Analog switch
Operating Supply Voltage	Dual : ±4.5 to ±7.5V Single : +9.0 to +15.0V	Dual : ±4.5 to ±7.5V Single : +9.0 to +15.0V	Dual : ±4.5 to ±7.5V Single : +9.0 to +15.0V
Serial Control	2-wired	2-wired	2-wired
Chip Address	2	2	4
THD (Vin=1Vrms, f=1kHz)	0.0004% typ.	0.0004% typ.	0.0004% typ.
Switch ON Resistance	–	15Ω typ.	15Ω typ.
Others	Independent Volume Control Volume: +31.5 to -95dB 2-input Selector(4ch.)	Independent Switch Control Low Impedance Switch	Independent Switch Control Low Impedance Switch
Package	SSOP32	SSOP32	SSOP32