SM5846AP

SEIKO NPC CORPORATION —1

Multi-function Digital Filter

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

I

8-times oversampling (interpolation)

I

Switchable 8/4 times oversampling output

I

Two master clock frequencies

(refer to Clock Functions)

• 384fs/512fs (normal-speed sampling)

• 192fs/256fs (high-speed sampling)

I

Digital deemphasis

• Compatible

with

32/44.1/48kHz

(normal-

speed) and 64/88.2/96kHz (high-speed) input

sampling frequencies

• ON/OFF control

I

Digital attenuator

• 128-step attenuation using linear 7-bit data set-

ting

I

Soft muting

• 1016/fs (normal-speed sampling)

• 2032/fs (high-speed sampling)

I

Output data round-off operation (normal round-off

or rectangular distribution dither round-off)

I

Selectable LR clock polarity

I

Microprocessor controllable

I

Input data format

• 2s complement, MSB first, alternating L/R

serial

• 16/20/24/32-bit data selectable

I

Output data format

• 2s complement, MSB first, simultaneous L/R

serial

• 20/24-bit data selectable.

I

24-bit internal data processing

I

Jitter-free mode/synchronous mode selectable

I

Crystal oscillator circuit built-in

I

TTL-compatible outputs

I

Molybdenum-gate CMOS

Filter Construction

I

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

I

Deemphasis filter (IIR filter)

I

Arithmetic units

•25

× 24-bit parallel adder

• 32-bit accumulator

I

Overflow limiter built-in

APPLICATIONS

I

Digital audio equipment

ORDERING INFOMATION

Device

Package

SM5846AP

28-pin DIP