AK5554 Datasheet, PDF (52/68 Pages) Asahi Kasei Microsystems – 4-Channel Differential 32-bit ADC

[AK5554]
■ LDO
The voltage range of TVDD is from 1.7 V to 1.98 V or from 3.0 V to 3.6 V. Set ON/OFF of the LDO by the
LDOE pin according to TVDD voltage (Table 21).
The internal LDO is switched ON/OFF depending on TVDD voltage range.
LDOE
L
L
H
H
PDN
L
H
L
H
LDO
OFF
OFF
OFF
ON
VDD18 pin
External Power Input 1.7-1.98 V
External Power Input 1.7-1.98 V
Pulled Down by 500  internally
LDO Voltage Output
Table 21. LDO Control
Additional Voltage Range to
TVDD pin
1.7-1.98 V
1.7-1.98 V
3.0-3.6 V
3.0-3.6 V
[1] TVDD=1.7-1.98 V, LDO is OFF (LDOE pin = “L”)
The internal LDO does not work properly when the TVDD voltage range is from 1.7 V to 1.98 V. Set the
LDOE pin to “L” to switch OFF the LDO. A 1.7 V - 1.98 V is supplied from the VDD18 pin for internal logic
circuits. The voltage difference between TVDD and VDD18 must be ±0.1 V or less.
[2] TVDD=3.0-3.6 V, LDO is ON (LDOE pin = “H”)
The internal LDO should be ON when the TVDD voltage range is from 3.0 V to 3.6 V. It will be the power
supply for the internal logic circuit. The VDD18 pin will be a connection terminal for a stabilization
capacitor. It is not possible to supply the power to external circuits from the VDD18 pin.
■ Reset
The AK5554 must be reset upon power up or when changing the clock setting or clock frequency. It can
be reset by the PDN pin and PW2-0 pins or RSTN bit and PW4-1 bits.
015099864-E-00
- 52 -
2016/03