RT5710C
Functional Pin Description
Pin No.
1
2
3
4
Pin Name
NC
EN
VIN
LX
No internal connection.
Enable control input.
Supply voltage input. The RT5710C operates from a 2.5V to 6V input.
Switch node.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum thermal dissipation.
Feedback.
Pin Function
5, 7 (Exposed Pad) GND
6
FB
Functional Block Diagram
EN
VIN
UVLO
OTP
Shut Down
Control
Error
Amplifier
R
C
C
COMP
Comparator
+
-
Ton
Logic
Control
Current
Limit
Detector
Current
Sense
LX
VIN
FB
V
REF
-
+
Driver
LX
GND
LX
Operation
The RT5710C
is a synchronous low voltage step-down
converter that can support the input voltage range from
2.5V to 6V and the output current can be up to 1A. The
RT5710C uses a constant on-time, current mode
architecture. In normal operation, the high-side P-MOSFET
is turned on when the switch controller is set by the
comparator and is turned off when the Ton comparator
resets the switch controller.
Low-side MOSFET peak current is measured by internal
RSENSE. The error amplifier EA adjusts COMP
voltage
by comparing the feedback signal (V
FB
) from the output
voltage with the internal 0.6V reference. When the load
current increases, it causes a drop in the feedback voltage
relative to the reference, then the COMP voltage rises to
allow higher inductor current to match the load current.
Copyright
©
2019 Richtek Technology Corporation. All rights reserved.
UV Comparator
If the feedback voltage (V
FB
) is lower than threshold voltage
0.2V, the UV comparator's output will go high and the
switch controller will turn off the high-side MOSFET. The
output under-voltage protection is designed to operate in
Hiccup mode.
Enable Comparator
A logic-high enables the converter; a logic-low forces the
IC into shutdown mode.
Soft-Start (SS)
An internal current source charges an internal capacitor
to build the soft-start ramp voltage. The V
FB
voltage will
track the internal ramp voltage during soft-start interval.
The typical soft-start time is 1.2ms.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS5710C-04
November 2019
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
