RT5028A Datasheet, PDF (20/41 Pages) Richtek Technology Corporation – RoHS Compliant and Halogen Free

RT5028A
Synchronous Step-Down DC/DC Converter
Four current mode synchronous step-down DC/DC
converters operate with internal power MOSFETs and
compensation network. These channels supply the power
core chip of portable system. They can be operated at
100% maximum duty cycle to extend battery operating
voltage range. When the input voltage is close to the output
voltage, the converter enters low dropout mode with low
output ripple. The operating frequency range of step-down
converter is 0.5MHz to 2MHz.
Four step-down converters have RAMP control function
as the following diagram.
DC/DC 1/2/3/4
Output Voltage2
DC/DC 1/2/3/4
Output Voltage4
DC/DC 1/2/3/4
Output Voltage1
DC/DC 1/2/3/4
Output Voltage3
REBOOT Function
As the REBOOT pin is set from low to high, the REBOOT
function will be active. The REBOOT's FSM is shown as
below. It concludes 100ms de-bouncing time and delay1/
delay2 power off delay time.
Table 1. REBOOT Input Control Setting
Description
Default
delayed2 _{00 : 100ms 10 : 1s}
10
delayed1 ^{01 : 500ms 11 : 2s}
10
Action
delayed1 power-off then
delayed2 power-on PMIC
From “LOW“ to “HIGH” rising
input into REBOOT pin with
100ms debouncing time
Wait for delayed1 time
Power off the PMIC
Wait for delayed2 time
Power on the PMIC
IRQ Table
We summarize all IRQ items in the register table. All IRQ_status registers are implemented as reset after read. If
IRQ_enable bit is Low, the IRQ_status bit will not update status. IRQ_enable will mask IRQ_status to trigger IRQ_PMIC
Low, so the system can decide which interrupt is necessary.
Waveform - (when the other IRQ_status are low)
IRQ_Enable_OVP
Mask
IRQ_Status
OVP
IRQ_Status_OVP
Reset after
Read
Reset after
Read
IRQ_PMIC
Waveform - (when the other IRQ_status are low)
* OTW125/OTW100 means the 125°C/100°C pre-warming over temperature. It only change IRQ status bits and don't
trigger IRQ pin.
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DS5028A-00 April 2016