
ML4872
VIN
100µF
20µH
(Sumida CD75)
ML4870
VL1 PWR GND
VIN
NC
GND
VL2
SHDN VOUT
IOUT
200µF
Figure 1. Application Test Circuit
IL
VIN
2
RSENSE
1
VL1
START-UP
6
VL2
SYNCHRONOUS
RECTIFIER
CONTROL
Q2
A2
VOUT
5
VOUT
+
–
A1
SHDN
4
BOOST
CONTROL
Q1
ISET
PWR GND
8
A3
2.4V
GND
3
Figure 2. PFM Regulator Block Diagram
IL(MAX)
IL
ISET
0
VOUT
VL2
0
Q1 ON
Q2 OFF
Q1 OFF
Q2 ON
Figure 3. Inductor Current and Voltage Waveforms
4