RT8025 Datasheet, PDF (2/13 Pages) Richtek Technology Corporation – 1.25MHz, 400mA, High Efficiency PWM Step-Down DC/DC Converter

RT8025
Typical Application Circuit
V_IN
2.5V to 5.5V
C_IN
4.7µF
1 _VIN
L
4.7µH
LX ⁵
RT8025
3 _{EN VOUT} 4
GND
2
Figure 1. Fixed Voltage Regulator
V_OUT
C_OUT
10µF
V_IN
2.5V to 5.5V
L
1 _VIN
4.7µH
LX ⁵
C_IN
4.7µF
RT8025
C1
R1
3 _EN
FB ⁴
GND
2
R2
V_OUT
C_OUT
10µF
Figure 2. Adjustable Voltage Regulator
VOUT = VREF x ⎜⎛1+ ^R1 ⎟⎞
⎝ ^R2 ⎠
with R1+ R2 ≤ 1MΩ and
VREF(Typ.) = 0.5V
Layout Guide
V_IN
L
V_OUT
V_IN
L
V_OUT
VIN 1
C_IN
GND 2
5 LX
C_OUT
GND
EN 3 4 VOUT
VIN 1
C_IN
GND 2
EN 3
5 LX
C_OUT
GND
R2
4 FB
R1
V_OUT
C1
Figure 3
Layout note:
1. The distance that CIN connects to VIN is as close as possible (Under 2mm).
2. COUT should be placed near RT8025.
www.richtek.com
2
DS8025-02 March 2011