OVERVIEW

The SM5846AP is a multi-function digital filter that incorporates 4/8 times oversampling digital audio signal reproduction, digital deemphasis, digital attenuation and soft mute functions. The I/O interface allows serial data transmission of 16/20/24/32-bit input data and 20/24-bit output data.

FEATURES

Functions

■ 8-times oversampling (interpolation)

■ Switchable 8/4 times oversampling output

■ Two master clock frequencies (refer to Clock Functions)

? 384fs/512fs (normal-speed sampling)

? 192fs/256fs (high-speed sampling)

■ Digital deemphasis

? Compatible with 32/44.1/48kHz (normal speed) and 64/88.2/96kHz (high-speed) input sampling frequencies

? ON/OFF control

■ Digital attenuator

? 128-step attenuation using linear 7-bit data setting

■ Soft muting

? 1016/fs (normal-speed sampling)

? 2032/fs (high-speed sampling)

■ Output data round-off operation (normal round-off or rectangular distribution dither round-off)

■ Selectable LR clock polarity

■ Microprocessor controllable

■ Input data format

? 2s complement, MSB first, alternating L/R serial

? 16/20/24/32-bit data selectable

■ Output data format

? 2s complement, MSB first, simultaneous L/R serial

? 20/24-bit data selectable.

■ 24-bit internal data processing

■ Jitter-free mode/synchronous mode selectable

■ Crystal oscillator circuit built-in

■ TTL-compatible outputs

■ Molybdenum-gate CMOS

Filter Construction

■ Interpolation filter (linear 3-stage FIR filter)

? Normal-speed sampling mode

1st stage (fs to 2fs) 121st order

2nd stage (2fs to 4fs) 21st order

3rd stage (4fs to 8fs) 13th order

? High-speed sampling mode

1st stage (fs to 2fs) 177th order

2nd stage (2fs to 4fs) 29th order

3rd stage (4fs to 8fs) 17th order

■ Deemphasis filter (IIR filter)

■ Arithmetic units

? 25× 24-bit parallel adder

? 32-bit accumulator

■ Overflow limiter built-in

APPLICATIONS

■ Digital audio equipment