DS6550A Datasheet, PDF (2/16 Pages) Richtek Technology Corporation – Synchronous DC-DC Step-Down Controller with 5V LDO

RT6550A
Functional Pin Description
Pin No.
1
2
3
4
5
Pin Name
EN
CS
FB
VO_DIS
LDO5
Pin Function
Enable control input.
Current limit setting. Connect a resistor to GND to set the threshold for
synchronous RDS(ON) sense. The GND - PHASE current limit threshold is 1/8th the
voltage seen at CS over a 0.2V to 2V range. There is an internal 10A current
source from LDO5 to CS.
Feedback voltage input. Connect FB to a resistive voltage divider from VOUT to
GND to adjust output from 2V to 5.5V.
Output discharge function.
5V linear regulator output. LDO5 is also the supply voltage for the low-side
MOSFET and analog supply voltage for the device.
6
VIN
Power input for 5V LDO regulator and buck controller.
7
BOOT
Bootstrap supply for high-side gate driver. Connect to an external capacitor
according to the typical application circuit.
8
UGATE
High-side gate driver output. UGATE swings between PHASE and BOOT.
9
PHASE
Switch node of MOSFETs. PHASE is the internal lower supply rail for the UGATE
high-side gate driver. PHASE is also the current sense input.
10
LGATE
Low-side gate driver output. LGATE swings between GND and LDO5.
11
(Exposed Pad)
GND
Ground. The exposed pad must be soldered to a large PCB and connected to GND
for maximum power dissipation.
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is a registered trademark of Richtek Technology Corporation.
DS6550A-00 September 2016