CS5151GD16 View Datasheet(PDF) - ON Semiconductor
Part Name
Description
MFG CO.
'CS5151GD16' PDF : 17 Pages View PDF
CS5151
and bypass capacitors, as well as other loads located on the
board will tend to reduce regulator di/dt effects on the circuit
board and input power supply. Placement of the power
component to minimize routing distance will also help to
reduce emissions.
2.0 μH
33 Ω
1000 pF
Figure 18. Filter Components
2.0 μH
+
1200 pF × 3.0/16 V
Figure 19. Input Filter
Layout Guidelines
1. Place 12 V filter capacitor next to the IC and connect
capacitor ground to pin 11 (PGND).
2. Connect pin 11 (PGND) with a separate trace to the
ground terminals of the 5.0 V input capacitors.
3. Place fast feedback filter capacitor next to pin 8 (VFFB)
and connect it’s ground terminal with a separate, wide
trace directly to pin 14 (LGND).
4. Connect the ground terminals of the Compensation
capacitor directly to the ground of the fast feedback
filter capacitor to prevent common mode noise from
effecting the PWM comparator.
5. Place the output filter capacitor(s) as close to the load
as possible and connect the ground terminal to pin 14
(LGND).
6. To implement adaptive voltage positioning, connect
both slow and fast feedback pins 16 (VFB) and 8
(VFFB) to the regulator output right at the inductor
terminal. Connect inductor to the output capacitors via
a trace with the following resistance:
RTRACE
+
80 mV
IMAX
This causes the output voltage to be +40 mV with no
load, and −40 mV with a full load, improving regulator
transient response. This trace must be wide enough to
carry the full output current. (Typical trace is 1.0 inch
long, 0.17 inch wide). Care should be taken to
minimize any additional losses after the feedback
connection point to maximize regulation.
7. If DC regulation is to be optimized (at the expense of
degraded transient regulation), adaptive voltage
positioning can be disabled by connecting to VFB pin
directly to the load with a separate trace (remote
sense).
8. Place 5.0 V input capacitors close to the switching
MOSFET.
Route gate drive signals VGATE (pin 10) with a trace
that is a minimum of 0.025 inches wide.
1.0 μF
VCOMP
VCC
0.1 μF
15
To the negative terminal
of the input capacitors
11
8
100 pF
5
VFFB
SOFT START
OFF TIME
To the negative terminal of the output capacitors
Figure 20. Layout Guidelines
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