AK5356 Datasheet, PDF (15/22 Pages) Asahi Kasei Microsystems – LOW POWER 20BIT ADC WITH MIC AMP & PGA

ASAHI KASEI
[AK5356]
n System Reset
The AK5356 is placed in the power-down mode by bringing PDN pin “L”. The control registers are also reset at the same
time. This reset should always be done after power-up. An analog initialization cycle starts after exiting the power-down
mode. The output data SDTO becomes available after 4128 cycles of LRCK clocks. During initialization, the ADC digital
data outputs of both channels are forced to a 2’s complement “0”. The ADC outputs settle to the data corresponding to the
input signal at the end of initialization (Settling time equals the group delay time approximately.).
As a normal initialization cycle may not be executed, nothing writes at address 01H during
initialization cycle after exiting power-down by PDN pin.
Power Supply
PDN pin
PDN pin may be “L” at power-up.
ADC Internal
State
PD
4128/fs
INIT -1
GD
AIN
SDTO
“0”data
Control register
INIT -2
Normal
PM
GD (1)
4128/fs
INIT -1
Normal
GD
(2)
(3) “0”data
(1)
Idle Noise
Normal
W rite to register
Inhibit
Normal
External clocks
(4)
The clocks may be stopped.
(5)
Figure 10. Power-Up / Power-Down Timing Example
• PD:
• PM:
• INIT-1:
• INIT-2:
• Inhibit:
Power-down state. ADC is output “0”.
Power-down state by Power Management bit. ADC is output “0”.
Initialization cycle of ADC
Initializing all control registers.
Inhibits writing to all control registers.
Note: See “Register Definitions” about the condition of each register.
(1). Digital output corresponding to the analog input is delayed by the Group Delay amount (GD). Output signal
gradually comes to settle to input signal during a group delay.
(2). If the analog signal does not be input, digital outputs have the offset to op-amp of input and some offset error of
a internal.
(3). ADC output data is “0” at power-down.
(4). When the external clocks (MCLK, BCLK and LRCK) are stopped, the AK5356 should be placed in the
power-down state.
(5). When external clocks are not supplied, inhibits writing to all control registes.
MS0171-E-00
- 15 -
2002/08