AK4390 Datasheet, PDF (14/32 Pages) Asahi Kasei Microsystems – Ultra Low Latency 32-Bit ΔΣ DAC

[AK4390]
OPERATION OVERVIEW
■ System Clock
The external clocks, which are required to operate the AK4390, are MCLK, BICK and LRCK. MCLK should be
synchronized with LRCK but the phase is not critical. The MCLK is used to operate the digital interpolation filter and the
delta-sigma modulator. Sampling speed and MCLK frequency are detected automatically and then the initial master clock
is set to the appropriate frequency (Table 1). When external clocks are changed, the AK4390 should be reset by the PDN
pin or RSTN bit. After exiting reset (PDN pin = “L” → “H”) at power-up etc., the AK4390 is in power-down mode until
MCLK is supplied.
The AK4390 is automatically placed in power saving mode when MCLK and LRCK stop during normal operation mode,
and the analog output is AVDD/2 (typ). When MCLK and LRCK are input again, the AK4390 is powered up. After
power-up, the AK4390 is in the power-down mode until MCLK and LRCK are input.
The MCLK frequency corresponding to each sampling speed should be provided (Table 2).
MCLK
Mode
1152fs
Normal
512fs
768fs
Normal
256fs
384fs
Double
128fs
192fs
Quad
Table 1. Sampling Speed
Sampling Rate
30kHz~32kHz
30kHz~54kHz
30kHz~108kHz
108kHz~216kHz
LRCK
fs
32.0kHz
44.1kHz
48.0kHz
88.2kHz
96.0kHz
176.4kHz
192.0kHz
128fs
N/A
N/A
N/A
N/A
N/A
22.5792
24.5760
MCLK (MHz)
192fs
256fs
384fs
512fs
N/A
8.1920 12.2880 16.3840
N/A
11.2896 16.9344 22.5792
N/A
12.2880 18.4320 24.5760
N/A
22.5792 33.8688
N/A
N/A
24.5760 36.8640
N/A
33.8688
N/A
N/A
N/A
36.8640
N/A
N/A
N/A
Table 2. System Clock Example (N/A: Not available)
768fs
24.5760
33.8688
36.8640
N/A
N/A
N/A
N/A
1152fs
36.8640
N/A
N/A
N/A
N/A
N/A
N/A
MCLK= 256fs/384fs supports sampling rate of 30kHz~108kHz (Table 3). But, when the sampling rate is 30kHz~54kHz,
DR and S/N will degrade by approximately 3dB as compared to when MCLK= 512fs/768fs.
MCLK
DR,S/N
256fs/384fs
117dB
512fs/768fs
120dB
Table 3. Relationship between MCLK frequency and DR, S/N (fs= 44.1kHz)
MS1046-E-00
- 14 -
2009/01