ML4851
27µH
(Sumida CD75)
V
IN
100µF
R
ML4851
A
V
V
PWR GND
IN
1µF
RESET
REF
GND
V
L
DETECT
V
OUT
V
OUT
I
OUT
100µF
R
B
Figure 1. ApplicationTest Circuit
L1
V
IN
6
V
L
START-UP
Q2
V
OUT
+
+
–
5
A2
V
–
C1
OUT
Q1
5µs
ONE SHOT
S
Q
Q
R
R1
R2
–
A1
+
V
REF
Figure 2. PFM Regulator Block Diagram
INDUCTOR
CURRENT
Q2
ON
Q2
ON
Q(ONE SHOT)
Q1 ON
Q1 ON
Q1 & Q2 OFF
Figure 3. PFM Inductor Current Waveforms and Timing
July, 2000
DATASHEET
4