OVERVIEW
The SM5843A×1 is a multi-function digital filter IC, fabricated using NPC’s Molybdenum-gate CMOS process, for digital audio reproduction equipment. It features 8-times oversampling (interpolation), digital deemphasis and soft muting functions. It accepts 16, 18, or 20-bit input data, and outputs data in 18 or 20-bit format. It operates using either a 384fs or 256fs system clock.

FEATURES
■ Filter configuration (2-channel processing)
   • 8-times oversampling (interpolation)
      - 3-stage FIR configuration
   • Deemphasis filter
      - IIR filter configuration for correct gain and phase characteristics
      - 2-channel independent ON/OFF control
      - 32/44.1/48 kHz sampling frequency (fs)
   • 21 × 22-bit parallel multiplier/25-bit accumulator for high precision
   • Overflow limiter
■ 2 oversampling filter characteristics
   • Sharp roll-off characteristic (response 1)
      - ≤ ±0.00005 dB passband ripple (0 to 0.4535fs)
      - ≥ 110 dB stopband attenuation (0.5465fs to 7.4535fs)
   • Slow roll-off characteristic (response 2)
      - ≤ ±0.00003 dB passband ripple (0 to 0.235fs)
      - ≥ 77 dB stopband attenuation (0.745fs to 7.255fs)
■ Soft muting
■ Digital attenuator
■ Input data format
   • 2s complement, MSB first
      - LR alternating, 16/18/20-bit serial, trailing data
      - LR alternating, 20-bit serial, leading data
      - LR simultaneous, 20-bit serial, leading data
■ Output data format
   • 2s complement, MSB first, LR simultaneous
   • 18/20-bit serial
   • BCKO burst (NPC format)
■ Dither processing ON/OFF control
■ Jitter-free/Sync mode selectable
■ 256fs/384fs system clock selectable
   • 21.2/14.2MHz maximum frequency (384fs/256fs)
■ 5 V supply
■ Crystal oscillator circuit built-in
■ TTL-compatible input/outputs
■ 28-pin plastic DIP and SOP
■ Molybdenum-gate CMOS

APPLICATIONS
■ CD players
■ DAT players
■ PCM systems