RT8026 Datasheet, PDF (2/12 Pages) Richtek Technology Corporation – 1.5MHz, 1A, High Efficiency PWM Step-Down DC/DC Converter

RT8026
Typical Application Circuit
V_IN
2.7V to 5.5V
L
1 _VIN
2.2µH
LX ⁹
C_IN
4.7µF
RT8026
C1
R1
VOUT
=
VREF
x ⎜⎝⎛1+
R1
R2
⎟⎠⎞
8 _EN
PGND
10
with R2 = 300kΩ to 60kΩ so the IR2 = 2μA to 10μA,
FB ⁵
GND
3
I_R2
R2
V_OUT
C_OUT
10µF
and (R1 x C1) should be in the range between 3x10^-6 and 6x10^-6 for component selection.
Figure 1. Typical Application Circuit for RT8026
Functional Pin Description
Pin No. Pin Name
Pin Function
1
VIN
Power Input.
2, 4, 6, 7 NC
No Internal Connection.
3
GND
Ground Pin.
5
FB
Feedback Input Pin. Receives the feedback voltage from a resistive divider
connected across the output.
8
EN
Chip Enable (Active High). It is recommended to add a 100kΩ resistor between EN
and GND pin.
9
LX
Pin for Switching. Connect this pin to the inductor.
10
PGND
Power Ground Pin.
Function Block Diagram
EN
VIN
Slope
Compensation
OSC &
Shutdown
Control
Current
Sense
Current
Limit
Detector
PWM
FB
Error
Comparator
Amplifier
RC
Control
Logic
Driver
Current
Detector
COMP
UVLO &
Power Good
Detector
V_REF
RS1
LX
RS2
www.richtek.com
2
PGND
GND
DS8026-02 March 2011