RT9018A/B
Pin Description
Pin No.
Pin Name
Pin Function
PSOP-8
WDFN 3x3
3
2
4
1
7, 8, 9
VIN
EN
Supply Input Voltage.
6
10
5
Chip Enable (Active-High).
VDD
Supply Voltage of Control Circuitry.
PGOOD Power Good Open Drain Output.
Set the output voltage by the internal feedback resistors when
7
4
ADJ
ADJ is grounded. If external feedback resistors is used, V
=
OUT
0.8V x (R1 + R2)/R2.
6
5
1, 2, 3
--
VOUT
NC
Output Voltage.
No Internal Connection.
8,
Ground. The exposed pad must be soldered to a large PCB and
connected to GND for maximum power dissipation.
Exposed Pad (11) GND
Exposed Pad (9)
Typical Application Circuit
R1+ R2
V
OUT
= 0.8×
R2
VIN
VIN
V
V
V
V
VOUT
VOUT
IN
OUT
OUT
IN
C
Dummy
R1
R2
10uF
10uF
RT9018A/B
RT9018A/B
10uF
10uF
Chip Enable
Chip Enable
ADJ
EN
ADJ
EN
PGOOD
PGOOD
V
V
DD
VDD
VDD
DD
GND
GND
100k
100k
1uF
1uF
V
V
OUT
OUT
Figure 1. Fixed Voltage Regulator
Figure 2. Adjustable Voltage Regulator
Function Block Diagram
VOUT
VIN
OCP
Driver
Error
Amplifier
OTP
POR
EN
VDD
Mode
ADJ
0.8V
PGOOD
-
+
0.72V
GND
www.richtek.com
2
DS9018A/B-04 September 2007
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
