RT7252A/B
Functional Pin Description
Pin No.
1
2
3
Pin Name
SW
VIN
BOOT
Pin Function
Switch Node. Connect to external L-C filter.
Input Supply Voltage. Must bypass with a suitably large ceramic
capacitor.
Bootstrap for High Side Gate Driver. Connect 0.01μF or greater ceramic
capacitor from BOOT to SW pin.
Chip Enable. A logic-high enables the converter; a logic-low forces the
RT7252A/B into shutdown mode, reducing the supply current to less
than 5μA. Attach this pin to VIN with a 100kΩ pull up resistor for
automatic startup.
Feedback Input Pin. For an adjustable output, connect an external
resistive voltage divider to this pin.
Power Good Indicator with Open Drain. The output of this pin is pulled to
low when the FB is lower than 0.7V; otherwise it is high impedance. A
100kΩ pull-high resistor is needed.
Ground. The exposed pad must be soldered to a large PCB and
connected to GND for maximum power dissipation.
No Internal Connection.
4
EN
5
6
7, 9 (Exposed Pad)
8
FB
PGOOD
GND
NC
Function Block Diagram
VIN
Internal
Regulator
Enable
Comparator
+
2.5V
-
5k
3V
1V
+
OSC
340kHz/800kHz
Slope Comp
+
V
A
V
CC
Foldback
Control
EN
Current Sense
Amplifier
-
V
A
OV
-
OV Comparator
+
-
+
BOOT
S
-
Q
Q
155m
0.4V
UV
R
Current
Comparator
SW
150m
UV Comparator
0.8V
FB
+
-
Error Amp
35pF 400k
1pF
PGOOD
Comparator
+
-
GND
0.7V
FB
PGOOD
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS7252A/B-01 April 2012
www.richtek.com
3
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
