MAX8505 MAXIM [Maxim Integrated Products], MAX8505 Datasheet - Page 13

• Manufacturer Part Number: MAX8505
• Description: 3A, 1MHz, 1% Accurate, Internal Switch Step-Down Regulator with Power-OK
• Manufacturer: MAXIM [Maxim Integrated Products]

Careful PC board layout is critical to achieve clean and
stable operation. The switching power stage requires
particular attention. Follow these guidelines for good
PC board layout:
1) Place decoupling capacitors as close to the IC as
2) Connect input and output capacitors to the power
possible. Keep power ground plane (connected to
PGND) and signal ground plane (connected to
GND) separate.
ground plane; connect all other capacitors to the
signal ground plane.
PC Board Layout Considerations
Applications Information
2.6V TO 5.5V
______________________________________________________________________________________
3A, 1MHz, 1% Accurate, Internal Switch
(10V CERAMIC)
V
2 x 22µF
IN
POWER-OK
Step-Down Regulator with Power-OK
C2
R7
10Ω
C5
0.1µF
(CENTRAL CMOSH-3)
R6
20kΩ
D1
IN
V
CTL
POK
CC
MAX8505
GND
BST
3) Keep the high-current paths as short and wide as
4) If possible, connect IN, LX, and PGND separately to
5) Ensure all feedback connections are short and
6) Route high-speed switching nodes away from sen-
TRANSISTOR COUNT: 3352
PROCESS: BiCMOS
COMP
PGND
0.1µF
C7
REF
LX
FB
possible. Keep the path of switching current short
and minimize the loop area formed by the high-side
MOSFET, the low-side MOSFET, and the input
capacitors. Avoid vias in the switching paths.
a large copper area to help cool the IC to further
improve efficiency and long-term reliability.
direct. Place the feedback resistors as close to the
IC as possible.
sitive analog areas (FB, COMP).
51kΩ
C9
3300pF
C6
0.01µF
R1
(FDV3H-IRON)
(6.3V CERAMIC)
Typical Application Circuit
1µH
L1
47µF
C
OUT
C8
220pF
Chip Information
R2
11.3kΩ
R3
22.6kΩ
V
1.2V
OUT
13