NJU26901
Digital Audio Delay
!
General Description
The NJU26901 is a digital audio delay. The NJU26901 provides delay-time
adjustment function and digital audio interface.
!
Package
!
FEATURES
NJU26901E2
•
2-Channel Audio Delay (24 bits data width).
Delay Time 85msec at fs = 48kHz ( 128msec at fs = 32kHz , 43msec at fs = 96kHz)
•
4 delay time modes( ¼, ½, ¾, 1 max. delay ) are selectable without a micro-computer.
•
To make long delay time, the NJU26901 can be connected serially.
•
Non-audio-signal data can be delayed by the NJU26901.
!
Hardware Specification
•
•
•
•
•
Digital Audio Interface
Digital Audio Format
Audio Bit Clock (BCK) Frequency
Package
Power Supply
:
:
:
:
:
1 Input port / 1 Output port
I
2
S 24bit BCK : 64fs, Slave Mode
13MHz Max ( approximate fs=200KHz)
EMP8 Pb-Free
2.5V ( +3.3V input tolerant )
Ver.2004-06-24
-1-
NJU26901
!
Function Block Diagram
NJU26901
BCKI
LRI
LRI
BCKI
SDI
SERIAL AUDIO
INTERFACE
Delay RAM
SERIAL AUDIO
INTERFACE
L/R in
L/R
½½½
SDO
Control
Logic
COUNT[1:0]
Fig. 1 Function Block Diagram
!
Pin Assignment
SDI
LRI
BCKI
VSS
1
2
NJU26901
3
4
6
5
COUNT[1]
COUNT[0]
8
7
VDD
SDO
Fig. 2 Pin Assignment
!
Pin Description
Table 1 Pin Description
No.
Symbol
I/O
Description
1
SDI
I
Audio Data Input
2
LRI
I
LR Clock Input
3
BCKI
I
Bit Clock Input
4
VSS
G
GND
5
COUNT[0]
I*
Delay Time Control 0
6
COUNT[1]
I*
Delay Time Control 1
7
SDO
O
Audio Data Output
8
VDD
P
Power Supply +2.5V
I : Input, I* : Input(internal pull-up), O : Output, P: +Power, G : GND
-2-
Ver.2004-06-24
NJU26901
!
Absolute Maximum Ratings
Table 2 Absolute Maximum Ratings
Parameter
Power Supply Voltage
Input Pin Voltage
Power Dissipation
Storage Temperature
Symbol
V
DD
V
TM
P
D
T
STR
Rating
-0.3 to +3.0
-0.3 to +3.6
100
-40 to +125
Units
V
V
mW
°C
!
Electric Characteristics
Table 3 Electric Characteristics (V
DD
=2.5V,Ta=25
℃
)
Parameter
Operating V
DD
Voltage
Operating Current
Operating Temperature
High Level Input Voltage
Low Level Input Voltage
High Level Output Voltage
Low Level Output Voltage
Input Current
Input Current
Input Capacitance
Input Rise/Fall transition Time
Symbol
V
DD
I
DD
T
OPR
V
IH
V
IL
V
OH
V
OL
I
IN
I
IN(PU)
C
IN
t
r
/ t
f
I
OH
= -2mA
I
OH
= -100uA
I
OL
= 2mA
I
OL
= 100uA
V
IN
= V
SS
½3.6V
V
IN
= V
SS
½3.6V
BCKI:13MHz
SDO:C
L
=25pF
Test Condition
Min.
2.25
-
-40
2.0
-
V
DD
-0.4
V
DD
-0.1
-
-
-15
-100
-
-
Typ.
2.5
1.0
25
-
-
-
-
-
-
-
-
10
-
Max.
2.75
-
85
3.3
0.5
-
-
0.4
0.1
+15
+15
-
100
Units
V
mA
℃
V
V
V
V
uA
uA
pF
ns
!
Equivalent Circuit
VDD
Input
terminal
VSS
Input
terminal
VSS
VDD
Output
terminal
VSS
VDD
Input Pin #1,2,3
Input Pin #5,6
Output Pin #7
Fig. 3 Input Terminal Equivalent Circuit
Ver.2004-06-24
-3-
NJU26901
!
Serial Audio Interface
Digital Audio format is I
2
S 24bit 64fs in fig. 5. The input and output format are the same I
2
S 24bit 64fs.
LRI
BCKI
M
SB
LSB
32 Clocks
M
SB
32 Clocks
LSB
Left Channel
Right Channel
SDI, SDO
23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Fig 5 Digital Audio Format (I S 24bits 64fs)
2
!
Function Description
•
SDI(#1) is serial audio input pin. The input audio data should be connected to this pin. The NJU26901 fetches
in the input audio data every LRI edge.
•
LRI(#2) is LR clock input pin. This LR clock frequency is the same frequency of the input audio signal.
LRI=”Low” shows SDI and SDO data are left channel data. LRI=”High” shows SDI and SDO data are right
channel data.
•
BCKI(#3) is bit clock input pin. This BCKI clock frequency is 64 times as large as the input audio signal.
•
SDO(#7) is serial audio output pin. The delayed audio data come out through this pin.
•
VDD(#8) is 2.5V power supply pin. VSS(#4) is GND pin. The decoupling capacitor is necessary between VDD
and VSS.
•
The input pins can interface to 3.3V ICs. The output pins can interface to 2.5V ICs. Refer to table3 “Electric
Characteristics”.
•
After Power-on RESET, there is possibility the NJU26901 generates random data for the delay time period set
by COUNT[0],[1] pins. If necessary, the mute circuit should be added.
!
Delay Time
•
The NJU26901 provides maximum 4097 samples delay and slave-mode audio interface. The delay time
depends on sampling frequency.
•
Delay time is controlled by COUNT[0], COUNT[1]. Table 5 shows Delay Time vs Sampling Frequency.
•
Detail delay time is evaluated by the following formula.
[sec]
Delay time = {1/(fs)}
×
(sampling number + 1)
•
The sampling number is incremented every LRI clock.
Table 5 Delay Time vs Sampling Frequency
Sampling Frequency
4/4
3/4
(fs)
(COUNT[1:0]=11)
(COUNT[1:0]=01)
192KHz
21ms
16ms
96KHz
43ms
32ms
88.2KHz
47ms
35ms
48KHz
85ms
64ms
44.1KHz
93ms
69ms
32KHz
128ms
96ms
Sampling number
(4097)
(3073)
1/2
(COUNT[1:0]= 10)
11ms
21ms
23ms
43ms
46ms
64ms
(2049)
1/4
(COUNT[1:0]= 00)
5ms
11ms
12ms
21ms
23ms
32ms
(1025)
Ver.2004-06-24
-5-
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