LTC4150

11

4150fc

APPLICATIONS INFORMATION

PC BOARD LAYOUT SUGGESTIONS

Keep all traces as short as possible to minimize noise

and inaccuracy. The supply bypass capacitor C2 should

be placed close to the LTC4150. The 4.7μF filter capacitor

be a low leakage, unpolarized type. Use a 4-wire Kelvin

sense connection for the sense resistor, locating it close

and powered load, see Figure 7.

4150 F07

PIN 1

TO BATTERY

TO CHARGER

LTC4150

Figure 7. Kelvin Connection on SENSE Resistor

TYPICAL APPLICATIONS

Figure 8 shows a typical application designed for a single

cell lithium-ion battery and 500mA maximum load current.

corresponds to 0.085mAh. Equation 14, derived from

Equation 2, gives the number of INT assertions for average

(14)

Loading the battery so that 51.5mA is drawn from it over

600 seconds results in 100 INT assertions. For an 800mAh

battery, this is (51.5mA • 1/6h) / 800mAh = 11% of the

battery’s capacity.

With a microcontroller supply = 5V, Equation 11 gives

A single cell lithium-ion battery can discharge as low as

2.7V.

From Equation 13, select R1 = 75k; the nearest standard

value for R2 is 76.8k.

Also from Equation 13, we choose R3 = 75k and R4 =

76.8k.

INT

SHDN

SHUTDOWN

R4

76.8k

R3

75k

CLR

POL

LTC4150

μP

C2

4.7μF

3k

10

9

8

7

6

1

2

5

4150 F08

GND

3k

5.0V

POWER-DOWN

SWITCH

47μF

LOAD

+

–

3

4

4.7μF

SINGLE-CELL

Li-Ion

3.0V ~ 4.2V

0.1Ω

R2

76.8k

R1

75k

+

Figure 8. Typical Application, Single Cell Lithium-Ion Battery