L6924D datasheet(30/38 Pages) STMICROELECTRONICS

30 / 38 page

Additional applications information

L6924D

30/38

Additional applications information

9.1

Selecting input capacitor

In most applications, a 1µF ceramic capacitor, placed close to the VIN and VINSN pins can be

used to filter the high frequency noise.

9.1.1

Selecting output capacitor

Typically, 1µF ceramic capacitor placed close to the VOUT and VOUTSN pin is enough to keep

voltage control loop stable. This ensures proper operation of battery absent detection in

removable battery pack applications.

9.2

Layout guidelines and demoboard description

The thermal loop keeps the device at a constant temperature of approximately 120°C which in

turn, reduces ICHG. However, in order to maximize the current capability, it is important to

ensure a good thermal path. Therefore, the exposed pad must be properly soldered to the

board and connected to the other layer through thermal vias. The recommended copper

thickness of the layers is 70

µm or more.

The exposed pad must be electrically connected to GND. Figure 24 shows the thermal image of

the board with the power dissipation of 1W. In this instance, the temperature of the case is

89°C, but the junction temperature of the device is given by the following formula:

Where the RTH J-A of the device mounted on board is 75°C/W, the power dissipated is 1W, and

the ambient temperature is 25°C.

In this case the junction temperature is:

AMB

DISS

THJ

−

Eq: 10-1

100

Eq: 10-2

L6924D Fiches technique(PDF) 30 Page - STMicroelectronics