Datasheet

11
2801234fe
LTC2801/LTC2802/
LTC2803/LTC2804
Table 3. Recommended Inductors
PART
NUMBER
I
SAT
(mA)
MAX DCR
(Ω)
SIZE
(mm)
MANUFACTURER
LQH2MCN100K02L 225 1.2
2 × 1.6 × 0.95
Murata
www.murata.com
LBC2016T100K 245 0.85
2 × 1.6 × 1.6
Taiyo Yuden
www.t-yuden.com
FSLB2520-100K 220 1.1
2.5 × 2 × 1.6
Toko
www.tokoam.com
Capacitor Selection
The small size of ceramic capacitors makes them ideal for
the LTC2801 family. X5R and X7R (preferred) types are
recommended because their ESR is low and they retain their
capacitance over relatively wide voltage and temperature
ranges. Use a voltage rating of at least 10V.
Table 4. Recommended Ceramic Capacitor Manufacturers
MANUFACTURER URL
Murata www.murata.com
TDK www.tdk.com
Taiyo Yuden www.t-yuden.com
AVX www.avxcorp.com
Kemet www.kemet.com
Inrush Current and Supply Overshoot Precaution
In certain applications, such as battery-operated and
wall-adapter devices, fast supply slew rates are generated
when power is connected. If V
CC
s voltage is greater than
4.5V and its rise time is faster than 10µs, the pins V
DD
and SW can exceed their ABS MAX values during start-
up. When supply voltage is applied to V
CC
, the voltage
difference between V
CC
and V
DD
generates inrush current
V
L
V
L
V
CC
V
CC
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
C1
C1
C5
C5
C3
C3TOP VIEW
= VIA
TOP VIEW
= VIA
C4
C4
C2
C2
L1
L1
2801 F09
SW CAP
V
DD
GND
SCALE R1 WITH C1, C2, 1/C4
C1
220nF
L1
10µH
4.5V TO 5.5V
V
CC
R1
1/8W
C4
1µF
C2
1µF
INRUSH
CURRENT
2801 F08
aPPlicationS inForMation
flowing through inductor L1 and capacitors C1, C2. The
peak inrush current must not exceed 2A. To avoid this
condition, add a resistor as shown in Figure 8. This
precaution is not relevant for supply voltages below 4.5V
or rise times longer than 10µs.
Board Layout
The board layout should minimize the length and area of
the SW and CAP traces. Suggested compact layouts for
the LTC2801 family are shown in Figure 9 (a) and (b).
Figure 9. Recommended Board Layouts for (a) Single and
(b) Dual Transceiver Parts
Figure 8. Supply Overshoot Protection for Input
Supplies of 4.5V or Higher
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