ATA663431_14 Datasheet, PDF (17/32 Pages) ATMEL Corporation – LIN SBC including LIN Transceiver

4.5 Voltage Regulator
Figure 4-12. VCC Voltage Regulator: Supply Voltage Ramp-up and Ramp-down
V
VS
12V
5.0V/3.3V
4.8V/2.9V
2.4V
NRES
5.0V/3.3V
t_VCC
t_Reset
VCC
V_{VS_th_N_f_down}
t
t_{res_f}
t
The voltage regulator needs an external capacitor for compensation and to smooth the disturbances from the
microcontroller. It is recommended to use a MLC capacitor with a minimum capacitance of 1.8µF together with a 100nF
ceramic capacitor. Depending on the application, the values of these capacitors can be modified by the customer.
When the Atmel ATA663431/ATA663454 is being soldered onto the PCB, it is mandatory to connect the heat slug with a
wide GND plate on the printed board to achieve a good heat sink.
The main power dissipation of the IC is created from the VCC regulator output current I_VCC, which is needed for the
application. Figure 4-13 shows the safe operating area of the Atmel ATA663431/ATA663454 without considering any output
current of the high-side output HSOUT.
Figure 4-13. Power Dissipation: Safe Operating Area: Regulator’s Output Current I_VCC versus Supply Voltage V_VS at
Different Ambient Temperatures (R_thja = 45K/W assumed)
90
Tamb = 85°C
80
Tamb = 95°C
70
60
Tamb = 105°C
50
Tamb = 115°C
40
Tamb = 125°C
30
20
10
0
5 6 7 8 9 10 11 12 13 14 15 16 17 18
V_VS [V]
ATA663431/ATA663454 [DATASHEET]
17
9232H–AUTO–09/14