LTC4001-1_15 Datasheet, PDF (18/20 Pages) Linear Technology – 2A Synchronous Buck Li-Ion Charger

LTC4001-1
APPLICATIONS INFORMATION
Layout Considerations
Switch rise and fall times are kept under 5ns for maximum
efficiency. To minimize radiation, the SW pin and input
bypass capacitor leads (between PV_IN and PGND) should
be kept as short as possible. A ground plane should be
used under the switching circuitry to prevent interplane
coupling. The Exposed Pad must be connected to the
ground plane for proper power dissipation. The other paths
contain only DC and/or 1.5MHz tri-wave ripple current and
are less critical.
With the exception of the input and output filter ca-
pacitors (which should be connected to PGND) all other
components that return to ground should be connected
to GNDSENS.
Recommended Components Manufacturers
For a list of recommend component manufacturers, contact
the Linear Technology application department.
L1
1.5μH
V_IN
4.5V TO 5.5V
C1
R1 R2 10μF
10k 1k _D1
LED
SW
V_INSENSE
PV_IN
SENSE
BATSENS
BAT
PGND
CHRG
LTC4001-1
NTC
R3
10k
AT 25°C
TO μP
FROM μP
FAULT
EN
PROG IDET
TIMER SS GNDSENS
R4
549Ω
C2
0.22μF
R5
549Ω
C3
0.1μF
L1: VISHAY DALE IHLP-2525AH-01
R3: NTC VISHAY DALE NTHS0603N02N1002J
C4 ⁺
10μF
2AHr
4.1V
Li-Ion
40011 F08
Figure 8. 2A Li-Ion Battery Charger with 3Hr Timer, Temperature
Qualification, Soft-Start, Remote Sensing and C/10 Indication
40011fa
18