33888 Datasheet, PDF (28/40 Pages) Freescale Semiconductor, Inc – Quad High-Side and Octal Low-Side Switch for Automotive

TYPICAL APPLICATIONS
TYPICAL APPLICATIONS
Figure 12 shows a typical lighting application for the
33888. 55W bulb driven with 10 milliohm outputs, and 21W
plus 5W lamps with 40 milliohm outputs.
+5.0 V
+5.0 V
V_PWR
100nF ^{8 X Relay or LED}
10 kΩ
4
MCU
4
A/D
A/D
33888
FS ^VDD
IHS0.IHS3
ILS
RST
SPI
WDIN
CSNS2-3
CSNS0-1
FSI
VPWR
LS4:11
HS2
HS3
HS0
GND
HS1
55 W
55 W
Loads
21 W 5.0 W
21 W 5.0 W
Figure 12. 33888 Typical Application Diagram
An excel tool has been created to calculate the dissipated
power and the junction temperature knowing the application
conditions in steady state, as shown in Figure 13.
The parameters to enter concern the loads (bulbs only
considered) and the board. They are VPWR, loads (in Watts),
PWM frequency, ambient temperature and thermal
impedance. The calculations are done with a R_DS(ON) at an
estimated junction temperature. The current is also
considered constant in the loads.
33888
28
Analog Integrated Circuit Device Data
Freescale Semiconductor