Datasheet

Data Sheet 15 Rev. 1.1, 2011-09-01
Smart Low-Side Power Switch
BTS3405G
Protection FunctionsThermal Protection
6 Protection Functions
The device provides embedded protection functions. Integrated protection functions are designed to prevent IC
destruction under fault conditions described in the data sheet. Fault conditions are considered as “outside” normal
operation.
6.1 Thermal Protection
The device is protected against over temperature due to overload and / or bad cooling conditions. To ensure this
a temperature sensor located in the Power MOSFET is used.
The BTS3405G has a thermal auto-restart function. After the device has cooled down it will switch on again see
Figure 12.
Figure 12 Error Signal via Input Current at Thermal Shutdown
6.2 Overvoltage Protection
When switching off inductive loads with low-side switches, the Drain-Source voltage V
D
rises above battery
potential, because the inductance intends to continue driving the current.
Figure 13 Output Clamp
The BTS3405G is equipped with a voltage clamp mechanism that keeps the Drain-Source voltage
V
D
at a certain
level. See Figure 13 and Figure 14 for more details.
IN
0
5V
t
Therm al shutdown
t
T
J
T
JSD
I
IN
I
IS
t
0
I
INf
ΔT
JSD
Ther m al_fault_autor estar t.emf
restart
Source
Drain
OutputC l am ap.em f