2801234fe

LTC2801/LTC2802/

LTC2803/LTC2804

Table 3. Recommended Inductors

PART

NUMBER

(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

recommendedbecausetheirESRislowandtheyretaintheir

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

and SW can exceed their ABS MAX values during start-

GND

GND

GND

GND

GND

GND

GND

GND

GND

GND

C1

C1

C5

C5

C3

C3

TOP VIEW

= VIA

TOP VIEW

= VIA

C4

C4

C2

C2

L1

L1

2801 F09

SW

CAP

GND

SCALE R1 WITH C1, C2, 1/C4

C1

220nF

L1

10µH

4.5V TO 5.5V

R1

1

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 1Ω 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