SM5842APT

OVERVIEW

The SM5842AP/APT 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), independent left and right- channel digital deemphasis, and soft muting functions. It accepts 16, 18, 20 or 24-bit input data, and outputs data in 18, 20, 22 or 24-bit format. It operates using either a 384fs or 256fs system clock at sampling frequencies up to 48 kHz + 10% (384fs SM5842AP, 384/256fs SM5842APT).

FEATURES

Functions
■ L/R 2-channel processing
■ 8-times oversampling (interpolation)
• ≤ ±0.00002 dB passband ripple
• ≥ 117 dB stopband attenuation
■ Digital deemphasis
• 32/44.1/48 kHz sampling frequency (fs)
• 2-channel independent ON/OFF control
■ Soft muting
• 2-channel independent ON/OFF control
■ Input data format
• 2s complement, MSB first
- LR alternating, 16/18/20/24-bit serial, trailing data
- LR alternating, 24-bit serial, leading data
- LR simultaneous, 24-bit serial, leading data
■ Output data format
• 2s complement, MSB first, LR simultaneous
• 18/20/22/24-bit serial
• BCKO burst (NPC format)
■ Dither round-up processing
• ON (dither rounding)/OFF (normal rounding) control
■ 25-bit internal data length
■ Jitter-free function for correct operation in the
presence of jitter between the system clock and LRCI clock
• ON (jitter-free mode)/OFF (sync mode) control
■ 256fs/384fs system clock selectable
• 384fs
- 21.2 MHz maximum frequency (at maximum fs = 55.2 kHz)
• 256fs
- 13 MHz maximum frequency (at maximum fs = 50.7 kHz, SM5842AP)
- 14.2 MHz maximum frequency (at maximum fs = 55.2 kHz, SM5842APT)
■ Crystal oscillator circuit built-in
■ TTL-compatible input/outputs
■ 5.0 ± 0.25 V supply
■ Molybdenum-gate CMOS process
■ 28-pin plastic DIP Filter Configuration
■ Linear phase 3-stage FIR interpolation filter
• 169-tap 1st stage (fs to 2fs)
• 29-tap 2nd stage (2fs to 4fs)
• 17-tap 3rd stage (4fs to 8fs)
■ Deemphasis filter
- IIR filter configuration for accurate gain and phase characteristics
■ 26 × 24-bit parallel multiplier/32-bit accumulator for high precision
■ Overflow limiter built-in

APPLICATIONS

■ CD players
■ DAT players
■ PCM systems