RT5800
V
IN
= 5V
VUVLO
VIN
V
IO
= 1.8V
V
IN
= 5V
VIN
V
IO
= 1.8V
VIO
VIO
EN
EN
SW EN
VOUT of
Buckx
T
SS
Register
Setting
EN Delay Time
(Factory Setting)
230μs
Boot
Time
70μs
VOUT of
Buckx
Discharge
resistor off
Discharge
resistor on
Digital/I C work
2
Figure 3. Start-up Sequence
V
IN
= 5V
VUVLO
VIN
V
IO
= 1.8V
VIO
Figure 6. Power-off Sequence by Software
Power Good Indication
The RT5800 provides a power good indication and this
function shows the status of output voltage. When
output voltage is between 110% and 90% of setting
voltage for each Buck, the PG indication bit goes high.
The relative registers are 0x14[7], 0x15[7] and 0x16[7].
Fault Detection and Interrupt Pin
EN
VOUT of
Buckx
SW EN
230μs
Boot
Time
EN Delay Time
(Factory Setting)
70μs
T
SS
Register
Setting
The RT5800 alerts the host when a warning, like Boot
and Hot Die, or fault events, like over-voltage,
under-voltage and over-temperature conditions have
occurred. Registers 0x13, 0x14, 0x15 and 0x16 can
help host to know if the fault or waning event happens.
These bits relative to events can be read and cleared.
Moreover, the RT5800 provides an interrupt pin with
the push-pull output capability and this pin shows these
events by using active low. When INT function is used,
set 0x33[6] = 1, 0x34[6] = 1 and 0x35[6] = 1. The pull
high output voltage of INT pin will be VIO voltage.
Register 0x32, 0x33, 0x34 and 0x35 can also set the
mask function to mask or pass the event flag output to
external interrupt pin. The overall detection function is
shown in Figure 7.
Figure 4. Start-up Sequence by Software
V
IN
= 5V
VIN
V
IO
= 1.8V
VIO
EN
VOUT of
Buck
Disable Delay Time
(Factory Setting)
Figure 5. Power-off Sequence
.
Copyright © 2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS5800-00
November 2019
www.richtek.com
7
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
