iC-MFP
8-FOLD FAIL-SAFE P-FET DRIVER
Rev A2, Page 10/13
Ipd()
Pull-down currents
V() increasing
In order to enhance noise immunity with limited power
dissipation at inputs INx, EN5, EN10 und ENFS the
pull-down currents at these pins have two stages. With
a rise in voltage at input pins INx, EN5, EN10 und
ENFS the pull-down current remains high until Vt()hi
(Electrical Characteristics No. 203); above this thresh-
old the device switches to a lower pull-down current.
If the voltage falls below Vt()lo (Electrical Character-
istics No. 204), the device switches back to a higher
pull-down current.
Ipd1()
Ipd2()
V() decreasing
Vt()hi
Vt()lo
V()
Figure 5: Pull-down currents at INx, EN5, EN10 and
ENFS
DETECTING SINGLE ERRORS
I(NOUTx)
If single errors are detected, safety-relevant applica-
tions require externally connected switching transistors
to be specifically shut down. Single errors can occur
when a pin is open (due to a disconnected bonding
wire or a bad solder connection, for example) or when
two pins are short-circuited.
[mA]
VB −V(NOUTx)
1
2
3
4
5
[V]
−400Ω
When two output of different logic levels are short-
circuited, the driving capability of the highside driver
will predominate, keeping the connected P-channel
FETs in a safe shutdown state.
−3.6
Figure 6: Output characeristics at NOUTx with loss
of VBR, GND or GNDR
With open pins VB, VBR, GND or GNDR iC-MFP
switches the output stages to a safe, predefined high
state via pull-up resistors and current sources at the
outputs, subsequently shutting down any externally
connected P-channel FETs.
Loss of VB potential
If power supply potential is not longer applied to VB,
the output stages are shut down and the outputs tied
to VBR via internal pull-up resistors with a typical value
of 200 kΩ.
Loss of VBR potential
If power supply potential is no longer applied to the
VBR-pin, the output stage lowside drivers are shut
down and the outputs actively tied to VB via the high-
side drivers.
I(NOUTx)
[µA]
VB −V(NOUTx)
1
2
3
4
5
[V]
Loss of GND potential
Ω
−200k
If ground potential is no longer applied to the GND-pin,
the output stage lowside drivers are shut down and the
outputs actively tied to VB via the highside drivers.
−20
Loss of GNDR potential
If ground potential is no longer applied to the GNDR-
pin, the output stage lowside drivers are shut down and
the outputs actively tied to VB via the highside drivers.
Figure 7: Output characeristics at NOUTx with loss
of VB
ICHAUS [ IC-HAUS GMBH ]
