RT7250A/B
Functional Pin Description
Pin No.
1
2
3
4
5
6
Pin Name
SW
VIN
BOOT
EN
FB
PGOOD
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
RT7250A/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. The output of this pin is low if the output voltage is
12.5% less than the nominal voltage. Otherwise, it is an open drain.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
No Internal Connection.
7,
GND
9 (Exposed Pad)
8
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.
DS7250A/B-01 May 2012
www.richtek.com
3
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
