rt8011 Richtek Technology Corporation, rt8011 Datasheet - Page 3

• Manufacturer Part Number: rt8011
• Description: 4mhz, Synchronous Step-down Regulator
• Manufacturer: Richtek Technology Corporation

Layout Guide
Functional Pin Description
DS8011/A-00 August 2006
RT8011
C
V
F
OUT
10
1
2
3
4
5
6
7
8
9
Pin Number
R1
V
Connect the FB pin directly to feedback resistors. The
resistor divider must be connected between V
GND.
R2
IN
C
V
possible
PGOOD
DD
IN
RT8011A
Figure 3. RT8011 Layout Guide
COMP
R
PVDD
must be placed between
C
and GND as closer as
COMP
VDD
COMP
FB
--
--
1
2
3
4
5
6
7
8
C
IN
10
6
7
8
9
COMP
RT8011
SHDN/RT
SYNC
GND
LX
PGND
PVDD
VDD
PGOOD
FB
GND
GND
Pin Name
5
4
3
2
1
Output capacitor must
be near RT8011
C
OUT
PGND
LX
GND
SYNC
SHDN/RT
OUT
V
Oscillator Resistor Input. Connecting a resistor to ground from this pin sets
the switching frequency. Forcing this pin to V
down.
External Clock Synchronization Input. The oscillation frequency can be
synchronized to an external oscillation applied to this pin. When tied to V
internal oscillator is selected.
Signal Ground. All small-signal components and compensation components
should connect to this ground, which in turn connects to PGND at one point.
Internal Power MOSFET Switches Output. Connect this pin to the inductor.
Power Ground. Connect this pin close to the (−) terminal of C
Power Input Supply. Decouple this pin to PGND with a capacitor.
Signal Input Supply. Decouple this pin to GND with a capacitor. Normally V
is equal to PVDD.
Power Good Indicator. Open-drain logic output that is pulled to ground when
the output voltage is not within ±12.5% of regulation point.
Feedback Pin. Receives the feedback voltage from a resistive divider
connected across the output.
Error Amplifier Compensation Point. The current comparator threshold
increases with this control voltage. Connect external compensation elements
to this pin to stabilize the control loop.
OUT
and
L1
R
OSC
V
LX should be
connected to
Inductor by wide
and short trace,
keep sensitive
compontents away
from this trace
IN
C
V
F
OUT
R1
V
Connect the FB pin directly to feedback resistors. The
resistor divider must be connected between V
GND.
IN
R2
Pin Function
C
V
possible
DD
Figure 4. RT8011A Layout Guide
IN
COMP
R
PVDD
must be placed between
C
and GND as closer as
VDD
COMP
COMP
FB
C
IN
5
6
7
DD
8
RT8011A
GND
GND
causes the device to be shut
4
3
2
1
Output capacitor must
be near RT8011A
C
RT8011/A
OUT
PGND
LX
GND
SHDN/RT
OUT
V
OUT
IN
www.richtek.com
and
and C
L1
R
OSC
LX should be
connected to
Inductor by wide
and short trace,
keep sensitive
compontents away
from this trace
OUT
.
DD
DD
,
3