RT2805A
Pin Configurations
(TOP VIEW)
BOOT
NC
NC
FB
2
3
4
8
SW
VIN
GND
EN
GND
9
7
6
5
SOP-8 (Exposed Pad)
Functional Pin Description
Pin No.
1
2, 3
4
5
6,
9 (Exposed Pad)
7
8
Pin Name
BOOT
NC
FB
EN
Pin Function
Bootstrap Input for High Side Gate Driver. Connect a 10nF or greater capacitor
from SW to BOOT to power the high side switch.
No Internal Connection.
Feedback Input. The feedback threshold is 1.222V.
Enable Input. EN is a digital input that turns the regulator on or off. Drive EN
higher than 1.4V to turn on the regulator, lower than 0.4V to turn it off. For
automatic startup, leave EN unconnected.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
Power Input. A suitable large capacitor should be connected from the VIN to
GND to eliminate noise on the input to the IC.
Switch Node. Note that a capacitor is required from SW to BOOT to power the
high side switch.
GND
VIN
SW
Function Block Diagram
VIN
Ramp
Generator
Current Sense
Amplifier
-
+
BOOT
EN
Regulator
Oscillator
500kHz
+
S
Q
R
-
Current
Comparator
Bootstrap
Control
GND
Driver
Reference
FB
12k
Error
+
Amplifier
-
SW
400k
30pF
13pF
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS2805A-00 November 2012
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
