AK4122A AKM [Asahi Kasei Microsystems], AK4122A Datasheet - Page 23

• Manufacturer Part Number: AK4122A
• Description: 24-Bit 96kHz SRC with DIR
• Manufacturer: AKM [Asahi Kasei Microsystems]

■
The AK4122A includes a digital de-emphasis filter (tc=50/15μs) by IIR filter corresponding to three sampling
frequencies (32kHz, 44.1kHz and 48kHz).
(1) When input port is DIR
When the input port is DIR and DEAU bit = “1”, the de-emphasis filter is enabled automatically by sampling frequency
(FS3-0 bit) and pre-emphasis information in the channel status. DEM1-0 bits can control the de-emphasis filter when
DEAU bit = “0”. When the de-emphasis filter is OFF, the internal de-emphasis filter is bypassed. When PEM bit = “0”,
the internal de-emphasis filter is always bypassed.
(2) When input port is PORT1 or PORT2
When PORT1 or PORT2 is selected as an input port, DEM1-0 bits can control the de-emphasis filter regardless of the
DEAU bit setting. In this case, the de-emphasis filter can not be enabled automatically. When the de-emphasis setting is
OFF, the internal de-emphasis filter is bypassed.
■
The AK4122A has a full power-down mode for all circuits that is activated by the PDN pin, and a partial power-down
mode activated by the PWN bit. The AK4122A should be reset once at power-up by bringing the PDN pin = “L”.
MS1076-E-01
De-emphasis Filter Control
System Reset and Power-Down
PDN pin:
PWN bit (Address 00H; D0):
All analog and digital circuits are placed in power-down and reset modes by bringing the PDN pin = “L”. All the
registers are initialized and clocks are stopped. Read/Write operations to the registers are disabled.
Unlike the PDN pin operation described above, internal registers and mode settings are not initialized. Read/Write
operations to the registers are enabled.
PEM
1
1
1
1
0
PEM
FS3
1
1
1
1
0
0
0
x
Table 12. De-emphasis Manual Control (DEAU bit = “0”)
Table 11. De-emphasis Auto Control (DEAU bit = “1”)
DEM1
DEM1
0
0
1
1
Table 13. De-emphasis Manual Control
FS2
0
0
1
1
0
0
0
x
(Others)
DEM0
DEM0
0
1
0
1
FS1
0
1
1
x
0
1
0
1
- 23 -
44.1kHz
48kHz
32kHz
Mode
OFF
FS0
0
0
1
x
44.1kHz
48kHz
32kHz
Mode
OFF
(default)
44.1kHz
48kHz
32kHz
Mode
OFF
OFF
(default)
[AK4122A]
2010/05