ADP1879 Analog Devices, ADP1879 Datasheet - Page 36

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

ADP1878/ADP1879
DIFFERENTIAL SENSING
Because the
control, a differential voltage reading is taken across the drain
and source of the low-side MOSFET. Connect the drain of the
low-side MOSFET s as close as possible to the SW pin (Pin 13) of
the IC. Likewise, connect the source as close as possible to the
PGND pin (Pin 11) of the IC. When possible, keep both of
these track lines narrow and away from any other active device
or voltage/current path.
Figure 91. Primary Current Pathways During the On State of the High-Side
MOSFET (Left Arrow) and the On State of the Low-Side MOSFET (Right Arrow)
ADP1878/ADP1879
operate in valley current-mode
Rev. 0 | Page 36 of 40
In addition, employ differential sensing between the outermost
output capacitor and the feedback resistor divider (see Figure 89
and Figure 90). Connect the positive terminal of the output
capacitor to the top resistor (R
of the output capacitor to the negative terminal of the bottom
resistor, which connects to the analog ground plane as well.
Keep both of these track lines, as previously mentioned, narrow
and away from any other active device or voltage/ current path.
Figure 92. Drain/Source Tracking Tapping of the Low-Side MOSFET for CS
LAYER 1: SENSE LINE FOR SW
(DRAIN OF LOWER MOSFET)
Amp Differential Sensing (Yellow Sense Line on Layer 2)
SW
PGND
T
LAYER 1: SENSE LINE FOR PGND
(SOURCE OF LOWER MOSFET)
). Connect the negative terminal
Data Sheet