Linear Technology LTC2977 Demo Board: Octal Power Supply Manager [Requires DC1613] DC2028A DC2028A Data Sheet
Product codes
DC2028A
LTC2977
90
2977fa
For more information
applicaTions inForMaTion
PCB ASSEMBLY AND LAYOUT SUGGESTIONS
Bypass Capacitor Placement
The LTC2977 requires 0.1µF bypass capacitors between
The LTC2977 requires 0.1µF bypass capacitors between
the V
DD33
pins and GND, the V
DD25
pin and GND, and the
REFP pin and REFM pin. If the chip is being powered from
the V
PWR
input, then that pin should also be bypassed
to GND by a 0.1µF capacitor. In order to be effective,
these capacitors should be made of high quality ceramic
dielectric such as X5R or X7R and be placed as close to
the chip as possible.
Exposed Pad Stencil Design
The LTC2977’s package is thermally and electrically
The LTC2977’s package is thermally and electrically
efficient. This is enabled by the exposed die attach pad
on the under side of the package which must be soldered
down to the PCB or mother board substrate. It is a good
practice to minimize the presence of voids within the
exposed pad inter-connection. Total elimination of voids
is difficult, but the design of the exposed pad stencil is
key. Figure 32 shows a suggested screen print pattern.
The proposed stencil design enables out-gassing of the
solder paste during reflow as well as regulating the finished
solder thickness. See IPC7525A.