iC-MFN
8-FOLD FAIL-SAFE N-FET DRIVER
Rev A2, Page 2/13
DESCRIPTION
iC-MFN is a monolithically integrated, 8-channel level puts to be actively tied to GND via the lowside tran-
adjustment device which drives N-channel FETs. sistors. If the ground potential ceases to be applied
The internal circuit blocks have been designed in to GND, the outputs are tied to GNDR by pull-down
such a way that with single errors, such as open resistors.
pins (VB, VBR, GND, GNDR) or the short-circuiting
of two outputs, iC-MFN’s output stages switch to a If the connection between the ground potential and
predefined, safe low state. Externally connected N- the GND pin is disrupted, the highside and lowside
channel FET are thus shut down safely in the event transistors of the output stages are shut down and
of a single error.
the outputs tied to GNDR via the pull-down resistors.
If on the other hand the connection between ground
The inputs of the eight channels consist of a Schmitt potential and the GNDR pin is disrupted, only the
trigger with a pull-down current source and are com- output stage highside transistors are shut down; the
patible with TTL and CMOS levels and are voltage- outputs are then actively tied to GND via the lowside
proof up to 40 V. The eight channels have a current- transistors.
limited push-pull output stage and a pull-down resis-
tor at the output. The hi-level at one of the inputs Pull-down currents provide the safe lo-level at open
EN5, EN10 or ENFS defines the output hi-level and inputs IN1. . . 8, EN5, EN10 and ENFS. The pull-
enables the outputs. The output hi-level is disabled down currents have two stages in order to minimize
with the lo-level at all inputs EN5, EN10 and ENFS or power dissipation with enhanced noise immunity.
with the hi-level at more than one input.
The status of the device is indicated with the Open-
iC-MFN monitors the supply voltage at VB and VBR Drain pin NOK and can be used for system diagnos-
pin and the voltages at the two ground pins GND and tics.
GNDR. Both power supply pins VB and VBR and
both pins GND and GNDR must be connected to- Temperature monitoring protects the device from too
gether externally in order to guarantee the safe low high power dissipation.
state of the output stages in the event of error.
The device is protected against destruction by ESD.
Should the supply voltage at VB undershoot a prede-
fined threshold, the voltage monitor causes the out-
ICHAUS [ IC-HAUS GMBH ]
