AK4497 Datasheet, PDF (65/98 Pages) Asahi Kasei Microsystems – Quality Oriented 32-Bit 2ch DAC

[AK4497]
■ LDO
When TVDD = 3.0 ~3.6V, the power for digital core circuit (DVDD) is supplied by the internal LDO by
setting the LDOE pin to “H”. Table 40 shows the DVDD pin statuses with the PDN and LDOE pins setting.
The internal LDO is powered up by setting the PDN pin from “L” to “H” (power-down release) and it starts
supping 1.8V DVDD. It takes 0.1ms (max.) to power-up the internal LDO.
PDN
L
L
H
H
LDOE
L
H
L
H
TVDD
1.7~3.6V
3.0~3.6V
1.7~3.6V
3.0~3.6V
Table 40. LDO Select Mode
DVDD
Hi-z
500ohm Pull Down
LDO OFF: Supply 1.7 ~ 1.98V to the DVDD pin externally
LDO ON: LDO outputs 1.8V.
The AK4497 has error detect function as shown in Table 41 for LDO operation (LDOE pin = “H”). The
internal LDO will be powered down and stop supplying the power to the digital core when an error is
detected. In this case, the analog signal output becomes Hi-z state. The AK4497 must be reset by setting
the PDN pin = “L” → “H” to recover from the error detection status.
Table 41. Error Detection
No Error
Error Detection Condition
1 Internal Reference Voltage Error Internal reference voltage does not rise.
2 LDO Over Voltage Detection
LDO voltage exceeds 2.2V.
3 LDO Over Current Detection
LDO current is 40mA or less, or 110mA or more.
■ Shutdown Switch
A shutdown switch is placed between the DVSS pin and VSS for the digital core to prevent SIDD leak of
DVDD digital power supply. The on-resistance is maximum 1Ω and the DVDD leak current will be 2uA at
the maximum.
When using LDO (LDOE pin = “H”), the shutdown switch is ON after counting by internal oscillator
following a power-down release (PDN pin “L” → “H”). It takes 2ms (max.) for the shutdown switch
power-up.
When not using LDO (LDOE pin = “L”), the shutdown switch is ON immediately after a power-down
release (PDN pin “L” → “H”). It takes 1us (max.) for the shutdown switch power-up.
■ Over Current Protection for Analog Output Pins
The AK4497 has channel independent over current detection function for analog output pins
(AOUTLP/LN and AOUTRP/RN pins). This function limits the current not to exceed 120mA when an
excessive current over 120mA (min) is detected. It is valid when the AK4497 is in power-on state.
Rev. 0.1
- 65 -
2015/11