u6268b ATMEL Corporation, u6268b Datasheet - Page 6

• Manufacturer Part Number: u6268b
• Description: U6268b Side-airbag Sensor Dual Interface
• Manufacturer: ATMEL Corporation

3.8
3.9
3.10
6
GND Pins
Power Dissipation
Test Hint
U6268B
A GND bond from the chip to pin 1 and pin 8 provides high ground breakage security and the
lowest voltage drop and ground shift between the IC and circuit ground. The four GND pins and
the die pad are directly connected to the copper leadframe, resulting in a very low thermal resis-
tance, R
parts of the housing be connected in a proper way with the GND pins.
Worst case calculation of the supply current I
I
Worst case calculation of the IC's power dissipation P
P
V
V
V
I
R
An integrated overtemperature protection generates a switch-off signal at a chip temperature of
typically T
If overtemperature is detected, only the corresponding channel will be disabled. The other chan-
nel stays enabled.
The RETURNx is switched off if the voltage at RETURNx exceeds 2V (short-circuit comparator
threshold) and overtemperature is detected.
The OUTx is switched off if the voltage at OCMx is higher than 4.6V (overcurrent detection level)
and overtemperature is detected. The OCM voltage monitors the output current at OUTx via the
current ratio of 0.1. The overcurrent-detection level of OUTx can be varied by changing the
OCMx resistor. If OUTx is switched off by overtemperature and overcurrent detection, the CLLx
output remains a logic low (overcurrent).
As the IC is only overtemperature-protected against short-circuit conditions at RETURNx or
OUTx, it has to be checked in each application that the chip temperature does not exceed
T
The overtemperature signal can be activated by connecting ENABLE1 or ENABLE2 to
9V/10 mA.
S
OUTx
jmax
V
S
diff
ret-sat
OCM
= 1.278
= (V
= Supply voltage (5.7 to 25V)
V
V
= V
= output current at pin OUTx = 0 to 60 mA
= 150°C in normal operation.
diff
diff
= resistor at pin OCMx
= 0.5 V saturation voltage return
S
S
= 3.6 V at 12 V V
= 0.8 V at 5.7 V V
thJC
to V
j
= 160°C and a switch-on signal at typically T
I
. To also achieve a low ambient thermal resistance (R
S
(I
) – [(V
OUTx
OUT1
voltage difference
+ I
S
– V
OUT2
diff
) + 18 mA
– V
S
S
25V
ret-sat
8.5V
)
(I
OUT1
S
+ I
:
OUT2
) + R
V
:
j
= 150°C.
OCM
((I
OUT1
thJA
) it is recommended metal
2
+ I
OUT2
2
)/81)]
4808B–AUTO–09/05