Datasheet

5/13
L4978
Figure 4. Test and evaluation board circuit.
Figure 5. PCB and component layout of the figure 4.
OSCILLATOR SECTION
Ramp Valley 0.78 0.85 0.92 V
Ramp peak V
cc
= 8V 2 2.15 2.3 V
V
cc
= 55V 9 9.6 10.2 V
Maximum duty cycle 95 97 %
Maximum Frequency Duty Cycle = 0%
R
osc
= 13kΩ, C
osc
= 820pF
300 kHz
Table 6. Electrical Characteristcs
(T
j
= 25°C, C
osc
= 2.7nF, R
osc
= 20kΩ, V
CC
= 24V, unless otherwise specified). “●" Specification Referred
to T
j
from 0 to 125°C
Symbol Parameter Test Condition Min. Typ. Max. Unit
D98IN834B
5
2
8
4
1
L4978
C
1
220µF
63V
C
8
330µF
V
O
=3.3V/2A
Vi=8V to 55V
R
1
20K
C
2
2.7nF
R
2
9.1K
C
4
22nF
3
7
L1
126µH
(77120)
6
D1
STPS3L60U
C
5
100nF
C
7
220nF
C
6
100nF
R
3
R
4
C1=220µF/63V EKE
C2=2.7nF
C5=100nF
C6=100nF
C7=220nF/63V
C8=330µF/35V CG Sanyo
L1=126µH KoolMu 77120 - 55 Turns - 0.5mm
R1=20K
R2=9.1K
D1=STPS3L60U
V
O
(V) R3(KΩ) R4(KΩ)
3.3
5.1
12
15
18
24
0
2.7
12
16
20
30
4.7
4.7
4.7
4.7
4.7
L4978