SM5950AM
Asynchronous Sample Rate Converter
OVERVIEW
The SM5950AM is a digital audio signal asynchronous sample rate converter LSI. It supports 16/20/24-bit
word-length input/output interface data. It also features a built-in digital deemphasis filter and direct mute
functions.
FEATURES
Functions
I
I
I
I
PINOUT
(Top view)
I
I
I
I
I
I
I
I
I
I
L/R 2-channel (stereo) processing
Input sample rate range: 20kHz to 100kHz
Output sample rate range: 30kHz to 50kHz
Operating sample rate conversion ratio (fso/fsi)
*1
: 0.45 to 2.205 selectable
*1
: fsi = input sample rate
fso = output sample rate
Asynchronous input and output clock timing
System clock input
• Input system clock: 1fsi (LRCI)
• Output system clock: 512fso (SCKO input)
Deemphasis filter function
• IIR-type filter
• fsi = 44.1kHz, 48kHz, 32kHz compatible
Direct mute function
Through mode operation
• Direct connection from input to output
Output data clocks (LRCO, BCKO)
• Slave mode: external inputs
• Master mode: derived from the output system
clock (SCKO)
Computation round-off processing
• Normal round-off
5V tolerant input pins for direct connection to 5V
operation devices
3.3V single supply
Package: 24-pin SSOP
LRCI
BCKI
DI
TMOD0
RSTN
VDD
IISI
IMOD0
IMOD1
DEEM
FS0
FS1
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
LRCO
BCKO
DOUT
SLAVE
SCKO
VSS
IISO
OMOD0
OMOD1
TMOD1
THROU
DMUTE
PACKAGE DIMENSIONS
(Unit: mm)
Weight: 0.23g
10.20 ± 0.30
10.05 ± 0.20
+
0.15
−
0.10
0.05
5.40 ± 0.20
Device
SM5950AM
Package
24-pin SSOP
1.80
0 to 10
0.10 ± 0.10
0.36 ± 0.10
0.10
0.12
M
Note: Dimensions without tolerance are reference values.
NIPPON PRECISION CIRCUITS INC.—1
+ 0.20
1.90
−
0.10
0.8
0.50 ± 0.20
ORDERING INFORMATION
7.80 ± 0.30
SM5950AM
FEATURES
Interfaces
I
Converter Performance
I
I
Input data format
• 2s-complement, MSB-first, L/R alternating serial
data
• IIS/non-IIS formats
Format
IMOD0
L
H
L
H
H or L
IMOD1
L
L
H
H
H or L
IISI
L
L
L
L
H
I
16-bit MSB-first right-justified
20-bit MSB-first right-justified
24-bit MSB-first right-justified
MSB-first left-justified
(leading 16 bits valid data)
IIS (leading 16 bits valid data)
L = Low input level, H = high input level
I
Output data format
• 2s-complement, MSB-first, L/R alternating serial
data
• Bit clock continuous (64fso)
Format
OMOD0
L
H
L
H
H or L
OMOD1
L
L
H
H
H or L
IISO
L
L
L
L
H
I
16-bit MSB-first right-justified
20-bit MSB-first right-justified
24-bit MSB-first right-justified
MSB-first left-justified (16-bit output)
IIS (16-bit output)
L = Low input level, H = high input level
Internal data word length: 20 bits
Deemphasis filter characteristics (IIR filter)
•
±
0.03dB gain deviation from ideal filter char-
acteristic
Anti-aliasing LPF characteristics (6 types of FIR
filter)
• Output/input sample rate conversion ratio auto-
matic filter select (6 FIR filters)
1. Up converter LPF
1.0 to 2.205 times
2. Down converter LPF I
about 0.92 times: 48.0kHz to 44.1kHz
3. Down converter LPF II
about 0.73 times: 44.1kHz to 32.0kHz
4. Down converter LPF III
about 0.67 times: 48.0kHz to 32.0kHz
5. Down converter LPF IV
about 0.50 times: 96.0kHz to 48.0kHz
6. Down converter LPF V
about 0.45 times: 96.0kHz to 44.1kHz
- Passband ripple: ± 0.0001dB
- Stopband attenuation: > 98dB
Converter insertion quantization noise level
• Internal calculation (quantization) noise
:
≤
– 96dB
• Output round-off noise:
- 16-bit output mode : – 98dB
- 20-bit output mode : – 122dB
- 24-bit output mode : – 146dB
• Output S/N ratio (theoretical values)
Output signal
word length
16 bits
20 bits
S/N ratio
16-bit input 20-bit input 24-bit input
– 92.5dB
– 93.9dB
– 93.9dB
– 94.0dB
– 96.2dB
– 96.2dB
– 94.0dB
– 96.2dB
– 96.2dB
Structure
I
Silicon-gate CMOS process
Applications
I
I
Digital audio equipment-interface sample rate
conversion
• AV amplifier, CD-R/RW, DAT, MD, DVC
Recording/editing equipment sample rate conver-
sion
24 bits
NIPPON PRECISION CIRCUITS INC.—2
SM5950AM
BLOCK DIAGRAM
LRCI
BCKI
DI
IMOD0
Input data interface
IMOD1
IISI
SCKO
RSTN
Sequencer block
Arithmetic
operation block
Interpolation
filter operation
Interpolation
operation
Output data
operation
DEEM
Deemphasis
filter operation
FS0
FS1
Conversion rate detector
Filter type
selector
Output operation
Output timing
operation
IISO
OMOD0
OMOD1
THROU
SLAVE
DMUTE
Though, mute, and
slave mode control
Output data interface
LRCO BCKO DOUT
NIPPON PRECISION CIRCUITS INC.—3
SM5950AM
PIN DESCRIPTION
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Name
LRCI
BCKI
DI
TMOD0
RSTN
VDD
IISI
IMOD0
IMOD1
DEEM
FS0
FS1
DMUTE
THROU
TMOD1
OMOD1
OMOD0
IISO
VSS
SCKO
SLAVE
DOUT
BCKO
LRCO
I/O
I
I
I
I
I
–
I
I
I
I
I
I
I
I
I
I
I
I
–
I
I
O
I/O
I/O
Sample rate clock input (fsi)
Bit clock input (32fsi to 64fsi)
Data input
IC test mode select pin (must be LOW for normal operation)
Reset pin
VDD supply (3.3V)
IIS input select pin
Input format select pin 0
Input format select pin 1
Deemphasis select pin
Deemphasis frequency select pin 0
Deemphasis frequency select pin 1
Direct mute select pin
Through mode select pin
IC test mode select pin (must be LOW for normal operation)
Output format select pin 1
Output format select pin 0
IIS output select pin
GND connection (0V)
Output system clock input (512fso)
Slave select pin
Data output
Bit clock input/output (64fso)
Sample rate clock input/output (fso)
Description
HIGH
–
–
–
Test
–
–
–
–
–
ON
–
–
ON
Through
Test
–
–
–
–
–
Slave
–
–
–
LOW
–
–
–
Normal
Reset
–
–
–
–
OFF
–
–
OFF
SRC
Normal
–
–
–
–
–
Master
–
–
–
NIPPON PRECISION CIRCUITS INC.—4
SM5950AM
SPECIFICATIONS
Absolute Maximum Ratings
V
SS
= 0V, VDD pin voltage = V
DD
Parameter
Supply voltage range
Input voltage range
Output voltage range
Storage temperature range
Power dissipation
Symbol
V
DD
V
I
V
O
T
stg
P
D
Rating
−
0.3 to 4.6
−
0.3 to 5.5
– 0.3 to V
DD
+ 0.3
−
55 to 125
400
Unit
V
V
V
°
C
mW
Note: Ratings also apply at supply switch ON and OFF.
Recommended Operating Conditions
V
SS
= 0V, VDD pin voltage = V
DD
Rating
Parameter
Supply voltage
Operating temperature
Symbol
min
V
DD
T
opr
3.0
– 40
typ
3.3
25
max
3.6
85
V
°
C
Unit
DC Electrical Characteristics
V
SS
= 0V, V
DD
= 3.0 to 3.6V, Ta =
−
40 to 85
°
C
Rating
Parameter
Current consumption
HIGH-level input voltage
(*1) (*3)
LOW-level input voltage
HIGH-level output voltage
(*2) (*3)
LOW-level output voltage
Input leakage current
(*1) (*3)
Pin
VDD
Symbol
I
DD
V
IH
V
IL
V
OH
V
OL
I
LH
I
LL
I
OH
=
−
2.0mA
I
OL
= 2.0mA
V
IN
= V
DD
V
IN
= 0V
(*A)
Condition
min
–
2.0
0
2.4
0
– 1.0
– 1.0
typ
22.0
–
–
–
–
–
–
max
30.0
5.5
0.7
V
DD
0.4
1.0
1.0
mA
V
V
V
V
µA
µA
Unit
(*A) All output pins with no load, System Clock frequency: F
SCKO
= 24.576MHz, Input word clock frequency: F
LRCI
= 48kHz, Supply voltage: V
DD
= 3.3V
Pin type
Note
(*1)
(*2)
(*3)
Type
Inputs
Output
Inputs/Outputs
Names
LRCI, BCKI, DI, TMOD0, RSTN, IISI, IMOD0, IMOD1, DEEM, FS0, FS1, DMUTE, THROU, TMOD1, OMOD1,
OMOD0, IISO, SCKO, SLAVE
DOUT
BCKO, LRCO
Note: All inputs and input/output pins are 5V compatible. Consequently, input voltages up to 5.5V can be connected. However, while input/output pins in
input mode can have input voltage up to 5.5V, input/output pins in output mode have output voltages that do not rise above VDD level. Plus, in out-
put mode, it is prohibited to use external pull-up to raise the voltage above VDD.
NIPPON PRECISION CIRCUITS INC.—5
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