LTC4100 Linear Technology, LTC4100 Datasheet - Page 22

• Manufacturer Part Number: LTC4100
• Description: Smart Battery Charger Controller
• Manufacturer: Linear Technology

LTC4100
APPLICATIO S I FOR ATIO
22
1. Input capacitors need to be placed as close as possible
2. The control IC needs to be close to the switching FET’s
3. Place inductor input as close as possible to switching
4. Place the output current sense resistor right next to
to switching FET’s supply and ground connections.
Shortest copper trace connections possible. These
parts must be on the same layer of copper. Vias must
not be used to make this connection.
gate terminals. Keep the gate drive signals short for a
clean FET drive. This includes IC supply pins that con-
nect to the switching FET source pins. The IC can be
placed on the opposite side of the PCB relative to above.
FET’s output connection. Minimize the surface area of
this trace. Make the trace width the minimum amount
needed to support current—no copper fills or pours.
Avoid running the connection using multiple layers in
parallel. Minimize capacitance from this node to any
other trace or plane.
the inductor output but oriented such that the IC’s
current sense feedback traces going to resistor are not
long. The feedback traces need to be routed together
as a single pair on the same layer at any given time with
U
U
W
Figure 12. Kelvin Sensing of Charging Current
U
DIRECTION OF CHARGING CURRENT
TO CSP AND BAT
R
SENSE
5. Place output capacitors next to the sense resistor
6. Output capacitor ground connections need to feed
Interfacing with a Selector
The LTC4100 is designed to be used with a true analog
multiplexer for the SafetySignal sensing path. Some se-
lector ICs from various manufacturers may not implement
this. Consult LTC applications department for more infor-
mation.
Electronic Loads
The LTC4100 is designed to work with a real battery.
Electronic loads will create instability within the LTC4100
preventing accurate programming currents and voltages.
Consult LTC applications department for more informa-
tion.
smallest trace spacing possible. Locate any filter
component on these traces next to the IC and not at the
sense resistor location.
output and ground.
into same copper that connects to the input capacitor
ground before tying back into system ground.
4100 F14
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