RT8058A Datasheet, PDF (2/14 Pages) Richtek Technology Corporation – 1.2MHz, 2A, High Efficiency PWM Step-Down DC/DC Converter

RT8058A
Typical Application Circuit
V_IN
2.6V to 5.5V
C1
10µF
RT8058A
8 _PVDD
LX ^{9, 10}
6 _EN
L1
3.3µH
C2
1µF
R3
100k
7 _VDD
5 _POK
FB ³
PGOOD
GND
4
PGND
1, 2,
11 (Exposed Pad)
R1
100k
R2
100k
C3
22µF
V_OUT
1.2V/2A
C4
1µF
Functional Pin Description
Pin No.
Pin Name
Pin Function
11
1, 2,
(Exposed
Pad)
PGND
Power Ground. Connect this pin close to the (–) terminal of C_IN and C_OUT. Exposed
pad should be soldered to PCB board and connected to GND.
3
FB
Feedback Input Pin. Receives the feedback voltage from a resistive divider
connected across the output.
4
GND
Signal Ground. Return the feedback resistive dividers to this ground, which in turn
connects to PGND at one point.
5
POK
Power Good Indicator. Open-drain logic output that is opened when the output
voltage exceeds 90% of the regulation point.
6
EN
Enable pin. A logical high level at this pin enables the converter, while a logical low
level causes the converter to shut down.
7
VDD
Signal Input Supply. Decouple this pin to GND with a capacitor. Normally VDD is
equal to PVDD.
8
PVDD
Power Input Supply of converter power stage. Decouple this pin to PGND with a
capacitor.
9, 10
LX
Internal Power MOSFET Switches Output of converter. Connect this pin to the
inductor.
Function Block Diagram
OSC
Slope
Com
Current Sense
PVDD
FB
0.6V
EA
Output
Clamp
Int-SS
0.3V
UV
OC
Limit
Control
Logic
Driver
0.533V
VREF POR
OTP
www.richtek.com
2
POK
VDD EN
LX
PGND
GND
DS8058A-02 April 2011