SM5849AF
NIPPON PRECISION CIRCUITS INC.
Asynchronous Sample Rate Converter
OVERVIEW
The SM5849AF is a digital audio signal, asynchronous sample rate converter LSI. It supports 16/20/24-bit
word length input data, 16/20/24-bit word length output data, 2kHz to 100kHz input sample rate range, and
4kHz to 200kHz output sample rate range. It also features a built-in digital deemphasis filter and digital attenu-
ator.
FEATURES
Functions
s
s
s
s
Filter Characteristics and Converter Efficiency
s
s
s
s
s
s
s
s
s
s
s
s
s
Left/right-channel processing (stereo)
2 to 100kHz input sample rate range (fsi)
4 to 200kHz output sample rate range (fso)
0.45 to 2.2-times variable sample rate conversion
ratio (fso/fsi)
Asynchronous input and output timing (clock
inputs)
System clock inputs (input and output clocks inde-
pendent)
• 256fsi or 384fsi input system clock select
• 256fso or 384fso output system clock select
Deemphasis filter
• IIR-type filter
• 44.1, 48 or 32kHz
Digital attenuator
• 11-bit data, 1025 levels
• Smooth attenuation change
• +12dB gain shift function
Direct mute function
Through mode operation
• Direct connection from input to output
Output data clocks (LRCO, BCKO)
• Slave mode: external input
• Master mode: output system clock generated
internally
Dither round-off processing
• Dither round-off ON/OFF selectable
3.3V single supply
80-pin QFP
Silicon-gate CMOS process
s
s
s
24-bit internal data word length
Deemphasis filter characteristics (IIR filter)
• ±0.03dB gain deviation from ideal filter charac-
teristics
Anti-aliasing LPF characteristics
• Output/input sample rate conversion ratio auto-
matic filter select (6 FIR filters)
- Up converter LPF
1.0 to 2.2 times
- Down converter LPF I
0.92 times: 48.0 to 44.1kHz
- Down converter LPF II
0.73 times: 44.1 to 32.0kHz
- Down converter LPF III
0.67 times: 48.0 to 32.0kHz
- Down converter LPF IV
0.5 times: 48.0 to 24.0kHz
- Down converter LPF V
0.45 times: 48.0 to 22.1kHz
• ±0.00005dB passband ripple
• > 110dB stopband attenuation
Converter noise levels
•
≤ −
110dB internal calculation (quantization)
noise
•
−
98dB (16-bit output),
−
122dB (20-bit output),
and
−
146dB (24-bit output) word rounding
noise
Output S/N ratio (theoretical values)
S/N ratio
Output signal
w ord length
16 bits
20 bits
24 bits
16-bit input
w ord length
94.8dB
97.7dB
97.7dB
20-bit input
w ord length
97.7dB
109.5dB
109.7dB
24-bit input
w ord length
97.7dB
109.7dB
110dB
NIPPON PRECISION CIRCUITS—1
SM5849AF
Interfaces
s
Input data format
• 2s-complement, L/R alternating, serial
• IIS/non-IIS format
Mode
1
2
16 bits
3
4
5
6
20 bits
7
8
9
10
24 bits
11
12
Left justified
IIS
M S B fi rst
M S B fi rst
Left justified
IIS
Right justified
Right justified
M S B fi rst
M S B fi rst
M S B fi rst
LSB first
Left justified
IIS
Right justified
Right justified
M S B fi rst
M S B fi rst
M S B fi rst
LSB first
W ord length
Data position
Right justified
Right justified
Data
sequence
M S B fi rst
LSB first
s
Output data format
• 2s-complement, MSB first, L/R alternating,
serial
• Continuous bit clock
Mode
1
2
3
4
5
6
7
W ord length
16 bits
20 bits
24 bits
24 bits
16 bits
Left justified
20 bits
24 bits
IIS
Nor mal
(non IIS)
Right justified
IIS selection
Data position
APPLICATIONS
s
Digital audio equipment-interface sample rate
conversion (AV amplifiers, CD-R, DAT, MD and
8mm VTRs)
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Commercial recording/editing equipment sample
rate conversion
ORDERING INFORMATION
D e vice
SM5849AF
P ackag e
80-pin QFP
NIPPON PRECISION CIRCUITS—2
SM5849AF
PIN DESCRIPTION
Number
1
2
3
4
5
6
7
Name
VDD
DI
BCKI
LRCI
VSS
ICLK
ICKSL
I/O
1
–
Ip
Ip
Ip
–
I
Ip
Supply voltage
Digital input signal
Bit clock input
W ord clock input
Ground
System clock input
System clock select. 384fs clock when HIGH, and 256fs clock when LOW .
Input format select
8
IFM1
Ip
IFM1
LOW
LOW
HIGH
9
IFM2
Ip
HIGH
IFM2
LOW
HIGH
LOW
HIGH
Data position
Right justified
Right justified
1
Left justified
IIS
Description
1. Data is in LSB first sequence
Input word length select
10
IWL1
Ip
IWL1
LOW
LOW
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
IWL2
NC
NC
NC
NC
NC
NC
NC
NC
VSS
VDD
DMUTE
MCOM
MDT/FSI1
MCK/FSI2
MLEN/DEEM
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
Ip
–
–
–
–
–
–
–
–
–
–
Ip
Ip
Ip
Ip
Ip
–
–
–
–
–
–
–
–
–
–
–
HIGH
HIGH
IWL2
LOW
HIGH
LOW
HIGH
Data length
16 bits
24 bits
20 bits
24 bits
No connection (must be open)
No connection (must be open)
No connection
No connection (must be open)
No connection (must be open)
No connection (must be open)
No connection (must be open)
No connection (must be open)
Ground
Supply voltage
Direct mute pin. Muting ON when HIGH.
Microcontroller control select. Microcontroller control when HIGH.
W h e n M C O N = H I G H : Microcontroller interface data input (MDT)
W h e n M C O N = L OW : Deemphasis filter fs select 1 (FSI1)
W h e n M C O N = H I G H : Microcontroller interface clock (MCK)
W h e n M C O N = L OW : Deemphasis filter fs select 2 (FSI2)
W h e n M C O M i s H I G H : Microcontroller interface latch enable (MLEN)
W h e n M C O M i s L OW : Deemphasis function select (DEEM)
No connection (must be open)
No connection (must be open)
No connection (must be open)
No connection (must be open)
No connection (must be open)
No connection (must be open)
No connection (must be open)
No connection (must be open)
No connection (must be open)
No connection (must be open)
No connection (must be open)
NIPPON PRECISION CIRCUITS—5
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