Nippon Precision Circuits (NPC) Announces Sample Production Run of an LSI with the World�fs Lowest Harmonic Distortion Ratio.

Tokyo- Nippon Precision Circuits Inc. announces the beginning of a sample production run of ΣDECO^(R) SM5865BM, a monochannel 24 bit input D/A converter LSI with the world's lowest harmonic distortion ratio.  The development of the SM5865BM draws upon NPC's own CMOS technology and experience in using the quantized multilevel noise-shaping method, both of which have been fundamentally important in the development of NPC's ΣDECO^(R) product line.  Moreover, the world's lowest total harmonic distortion ratio was achieved in the SM5865BM as a result of applying a new method developed by NPC, a method named as the New Precision Dynamic Element Matching(NPDEM) method. Applying this new method on a full sine wave input resulted in achieving a total harmonic distortion ratio of 0.0004% (-108dB).

The quantized multilevel noise-shaping method used in the SM5865BM is an enhanced version over previous implementations of the method.  This enhanced version is essentially a third-order noise-shaper with 23 levels of quantization. Such enhancement allows the theoritical Signal-to-Noise Ratio to be maintained above 120dB while also effectively controlling residual noise outside the audio band.

Preciseness for matching analog elements such as resistors.capacitors and etc. on a chip is greatly increased by the newly developed NPDEM.  The new method enabled a significant improvement in the signal-to-noise (S/N) ratio, an increase in the dynamic range, and lowering of the total harmonic distortion ratio.  Moreover, compared with the Pulse Width Modulation (PWM) method used in many 1 bit D/A converters this new method has the advantage of limiting deterioration of analog precisness that results from jitter in the system clock.There fore NPDEM enables a high precisness of D/A conversion, even in application that PLL creates system clock (For example DVD-player).

Combining the SM5865BM with NPC's SM5847AF LSI, a DVD-Audio 8 times oversampling/digital filter LSI, supports the 24 bit/192kHz input signals of DVD videoplayers. The above combination also supports input signals for DVD audioplayers including 24 bit/192kHz input signals, the fastest standardized sampling rate established in 1999. The ability to handle such high sampling rate signals allows for the possibility to produce high quality digital signal reproductions of the original analog signals.

NPC hopes to use similar technology as employed in the SM5865BM to design other LSI needed for audio applications.