ADP1879 Analog Devices, ADP1879 Datasheet - Page 33

• Manufacturer Part Number: ADP1879
• Description: Synchronous Buck Controller with Constant On-Time and Valley Current Mode with Power Saving Mode
• Manufacturer: Analog Devices

Data Sheet
LAYOUT CONSIDERATIONS
The performance of a dc-to-dc converter depends highly on
how the voltage and current paths are configured on the printed
circuit board (PCB). Optimizing the placement of sensitive
analog and power components are essential to minimize output
ripple, maintain tight regulation specifications, and reduce
PWM jitter and electromagnetic interference.
V
V
REG
OUT
C
53pF
PAR
0.1µF
R
C2
R7 10kΩ
TOP
Figure 86.
R
1kΩ
2kΩ
BOT
C
430pF
100kΩ
R
57kΩ
R
1µF
C
C
RES
C1
SEPARATE ANALOG
GROUND PLANE FOR
COMPENSATION AND
FEEDBACK RESISTORS
SENSITIVE ANALOG
COMPONENTS
LOCATED FAR
FROM NOISY
POWER SECTION
ADP1878
Figure 87. Overall Layout of the ADP1878/ADP1879 High Current Evaluation Board
JP3
1
2
3
4
5
6
7
C
22µF
VIN
COMP
EN
FB
GND
RES
VREG
VIN
ADP1878/
ADP1879
High Current Evaluation Board Schematic (Blue Traces Indicate High Current Paths)
PGOOD
PGND
DRVH
DRVL
INPUT CAPACITORS
ARE MOUNTED CLOSE
TO DRAIN OF Q1/Q2
AND SOURCE OF Q3/Q4
BST
SW
SS
14
13
12
11
10
9
8
C
100nF
5kΩ
BST
HIGH VOLTAGE INPUT
C
34nF
SS
Rev. 0 | Page 33 of 40
V
REG
V
Q1
Q3
IN
= 12V
Q2
Q4
22µF
C3
Figure 86 shows the schematic of a typical
used for a high current application. Blue traces denote high current
pathways. VIN, PGND, and V
possibly replicated, descending down into the multiple layers.
Vias should populate, mainly around the positive and negative
terminals of the input and output capacitors, alongside the source
of Q1/Q2, the drain of Q3/Q4, and the inductor.
R
2Ω
C
1.5nF
1.0µH
SNB
SNB
MURATA: (HIGH VOLTAGE INPUT CAPACITORS)
PANASONIC: (OUTPUT CAPACITORS)
INFINEON FETs:
WÜRTH INDUCTORS:
22µF
22µF, 25V, X7R, 1210 GRM32ER71E226KE15L
270µF, SP-SERIES, 4V, 7mΩ, EEFUE0G271LR
BSC042N03MS G (LOWER SIDE)
BSC080N03MS G (UPPER SIDE)
1µH, 3.8mΩ, 16A, 7443552100
C4
C24
N/A
270µF
22µF
C20
+
C5
C25
N/A
+
22µF
270µF
C6
C21
+
OUTPUT
CAPACITORS
ARE MOUNTED
AT RIGHTMOST
AREA OF
EVALUATION
BOARD
C26
N/A
V
22µF
+
OUT
270µF
C7
C22
+
= 1.8V, 15A
C27
N/A
OUT
N/A
+
C8
270µF
traces should be wide and
ADP1878/ADP1879
C23
+
C14 TO C19
N/A
N/A
C9
+
ADP1878/ADP1879