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

LTC4001
APPLICATIO S I FOR ATIO
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 capacitors
(which should be connected to PGND) all other compo-
nents that return to ground should be connected to
GNDSENS.
Recommended Components Manufacturers
For a list of recommend component manufacturers, con-
tact 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
NTC
TO µP FAULT
R3
10k
AT 25°C
FROM µP
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
4.2V
Li-Ion
4001 F08
Figure 8. 2A Li-Ion Battery Charger with 3Hr Timer, Temperature
Qualification, Soft-Start, Remote Sensing and C/10 Indication
4001f
18