LTC3703-5_15 Datasheet, PDF (29/32 Pages) Linear Technology – 60V Synchronous Switching Regulator Controller

LTC3703-5
APPLICATIO S I FOR ATIO
5. Place the small-signal components away from high
frequency switching nodes (BOOST, SW, TG, and BG). In
the layout shown in Figure 20, all the small signal compo-
nents have been placed on one side of the IC and all of the
power components have been placed on the other. This
also helps keep the signal ground and power ground
isolated.
6. A separate decoupling capacitor for the supply, V_CC, is
useful with an RC filter between the DRV_CC supply and V_CC
pin to filter any noise injected by the drivers. Connect this
capacitor close to the IC, between the V_CC and GND pins
and keep the ground side of the V_CC capacitor (signal
ground) isolated from the ground side of the DRV_CC
capacitor (power ground).
7. For optimum load regulation and true remote sensing,
the top of the output resistor divider should connect
independently to the top of the output capacitor (Kelvin
connection), staying away from any high dV/dt traces.
Place the divider resistors near the LTC3703-5 in order to
keep the high impedance FB node short.
8. For applications with multiple switching power convert-
ers connected to the same input supply, make sure that the
input filter capacitor for the LTC3703-5 is not shared with
other converters. AC input current from another converter
could cause substantial input voltage ripple, and this could
interfere with the operation of the LTC3703-5. A few
inches of PC trace or wire (L ≅ 100nH) between C_IN of the
LTC3703-5 and the actual source V_IN should be sufficient
to prevent input noise interference problems.
V_CC
V_IN
R_C1
C_C2
R2
R_C2
R1
C_C3
1
16
MODE/SYNC V_IN
R_{SET 2}
FSET
BOOST ¹⁵
3 _COMP
TG ¹⁴
C_C1
4
FB
SW ¹³
R_{MAX 5} ^LTC3703-5 ₁₂
I_MAX
VCC
6
INV
C_SS
7 _RUN/SS
11
DRV_CC
BG ¹⁰
8 _GND
BGRTN ⁹
D_B
M1
C_B
R_F
C_DRVCC
X5R
M2
C_VCC
X5R
+
C_IN
L1
+
C_OUT
D1
+
V_OUT
–
37035 F18
Figure 20. LTC3703-5 Buck Converter Suggested Layout
37035fa
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