MAX8741EAI+T Maxim Integrated, MAX8741EAI+T Datasheet - Page 27

• Manufacturer Part Number: MAX8741EAI+T
• Description: Current & Power Monitors & Regulators 500kHz Multi-Out Pwr Supply Controller
• Manufacturer: Maxim Integrated

Specifications of MAX8741EAI+T

• Rohs: yes
• Product: Power Monitors
• Supply Voltage - Max: 30 V
• Supply Voltage - Min: 4.2 V
• Input Voltage Range: 4.2 V to 30 V

Ideally, surface-mount power components are butted up
to one another with their ground terminals almost touch-
ing. These high-current grounds are then connected to
each other with a wide filled zone of top-layer copper so
they do not go through vias. The resulting top layer “sub-
ground-plane” is connected to the normal inner-layer
ground plane at the output ground terminals, which
ensures that the IC’s analog ground is sensing at the sup-
ply’s output terminals without interference from IR drops
and ground noise. Other high-current paths should also
be minimized, but focusing primarily on short ground and
current-sense connections eliminates about 90% of all PC
board layout problems.
2) Place the IC and signal components. Keep the main
switching nodes (LX nodes) away from sensitive
analog components (current-sense traces and REF
capacitor). Place the IC and analog components on
the opposite side of the board from the power-
switching node. Important: The IC must be no more
than 10mm from the current-sense resistors. Keep
the gate-drive traces (DH_, DL_, and BST_) shorter
than 20mm and route them away from CSH_, CSL_,
and REF.
500kHz Multi-Output Power-Supply Controllers
d) LX node (MOSFETs, rectifier cathode, induc
tor): 15mm max length
______________________________________________________________________________________
with High Impedance in Shutdown
3) Use a single-point star ground where the input
Figure 9. Kelvin Connections for the Current-Sense Resistors
ground trace, power ground (subground plane), and
normal ground plane meet at the supply’s output
ground terminal. Connect both IC ground pins and all
IC bypass capacitors to the normal ground plane.
MAX8741/MAX8742
HIGH-CURRENT PATH
SENSE RESISTOR
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