IC-DX_11 Datasheet, PDF (8/10 Pages) IC-Haus GmbH – UNIVERSAL DIGITAL SENSOR OUTPUT DRIVER

iC-DX
preliminary
UNIVERSAL DIGITAL SENSOR OUTPUT DRIVER
tpio
ttrig()
IN
EN
NEP
OUT
Figure 7: Timing diagram in push-pull operation
mode
CVOUT
100nF..
VOUT
REG
+
5V
-
VREF
<150 C
DIGITAL INPUT
OE
IN
&
&
iC-DX
Rev A3, Page 8/10
High Side Switch
NEP
36V
VB
..30V
VB
CVB
1μF
OUT
36V
EN
Low Side Switch
GND
GND
Figure 8: Block diagram with EN and NEP internal
signals
CIRCUIT PROTECTION
The iC-DX is reverse polarity protected via internal
circutry. As far as the maximum voltage ratings are not
exceeded, no possible supply combination at the line
side pins (VB, GND and OUT) can damage the chip.
Since the chip current consumption is relatively low,
discharging of the backup capacitor C1 can be very
slow, and injected charge through disturbances may
in general result in capacitor voltage exceeding maxi-
mum ratings, leading to malfunction or destruction of
circuitry and associated parts. Thus EMC require-
ments will afford more external circuitry. Figure 9
shows the iC-DX with the additional protective device
D1, D2 and D3.
For over-voltage protection, the suppressor diodes
D1,D2 and D3 absorbs transients on supply line in-
jected externally on the cable. Clamp voltage of the
diodes should be rated slightly above maximum speci-
fied supply voltage.
These currents can be passed to ground or to VB
by the internal ESD diodes of the iC-DX. Whereas
negative current injection will simply be drained off to
ground, positive current injection will charge capacitor
C1 further to higher voltages. If not suppressor diodes
nor any other over-voltage protection is implemented,
the backup capacitor C1 should be kept small. A typi-
cal 100nF value is normally OK.
Suggested protective devices
At VB_max of 36V, suppressor diodes with a breakdown
voltage from 36V has to be chosen in order to minimize
the energie in iC-DX for higer Voltages. For example
Diode type like Vishay GSOT36C or PJSD36W from
Pan Jit should be enouch as protection.
Figure 9: Circuit schematic showing protective de-
vices