LTC3785-1 Linear Technology, LTC3785-1 Datasheet - Page 17

• Manufacturer Part Number: LTC3785-1
• Description: Buck-Boost Controller
• Manufacturer: Linear Technology

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APPLICATIONS INFORMATION
• Segregate the signal and power grounds. All small-signal
• Place switch B and switch C as close to the controller
• Keep the high dV/dT SW1, SW2, V
• The path formed by switch A, switch B, D1 and the C
• The output capacitor (–) terminals should be connected
• Connect the V
components should return to the GND pin at one point.
The sources of switch B and switch C should also con-
nect to one point at the GND of the IC.
as possible, keeping the PGND, BG and SW traces
short.
TG2 nodes away from sensitive small-signal nodes.
capacitor should have short leads and PC trace lengths.
The path formed by switch C, switch D, D2 and the
C
trace lengths.
as close as possible to the (–) terminals of the input
capacitor.
the V
OUT
CC
capacitor also should have short leads and PC
and PGND pins.
CC
decoupling capacitor C
BST1
, V
BST2
VCC
closely to
, TG1 and
IN
• Connect the top driver boost capacitor C
• Connect the input capacitors C
• Connect FB and V
• Route I
• Route I
• Connect the feedback network close to IC, between the
the V
capacitor C
tors C
tors carry the MOSFET AC current in boost and buck
mode.
terminals of C
decoupling capacitor is used, it should be as close as
possible to the LTC3785-1 GND pin.
trace spacing. Ensure accurate current sensing with Kel-
vin connections across MOSFET A or sense resistor.
PC trace spacing. Ensure accurate current sensing
with Kelvin connections across MOSFET D or sense
resistor.
V
C
and FB pins.
BST1
OUT
SVIN
SVOUT
and SW1 pins. Connect the top driver boost
close to the power MOSFETs. These capaci-
B
and I
closely to the V
and I
OUT
SSW1
SENSE
and signal ground. If a small V
SSW2
leads together with minimum PC
pin resistive dividers to the (+)
leads together with minimum
BST2
IN
LTC3785-1
and SW2 pins.
and output capaci-
A
closely to
17
SENSE
37851f