Ap5101, New prod uc t applications information – Diodes AP5101 User Manual
Page 12
AP5101
1.5A Step-Down Converter with 1.4MHz Switching
Frequency
AP5101
Document number: DS32258 Rev. 1 - 2
12 of 15
July 2010
© Diodes Incorporated
NEW PROD
UC
T
Applications Information
(Continued)
External Bootstrap Diode
It is recommended that an external bootstrap diode be added when the input voltage is no greater than 5V or the 5V rail is
available in the system. This helps improve the efficiency of the regulator. The bootstrap diode can be a low cost one such as
IN4148 or BAT54.
AP5101
BST
SW
10nF
BOOST
DIODE
5V
7
1
Figure 4. External Bootstrap Diode
Manufacturer
Part Number
Inductance(µH)
Max DCR
(
Ω)
Current
Rating (A)
Dimensions
L x W x H (mm3)
Toko
A921CY-4R7M
4.7
0.027
1.66
6.0 x 6.3 x 3.0
Sumida
CDRH4D28C/LD
4.7
0.036
1.50
5.1 x 5.1 x 3.0
Wurth Electronics
7440530047
4.7
0.038
2.00
5.8 x 5.8 x 2.8
Table 2. Suggested Surface Mount Inductors