U6268B Datasheet, PDF (3/12 Pages) TEMIC Semiconductors – Side-Airbag Sensor Dual Interface

U6268B
35
30
25
22.4
21.4
20
Vout max
Vout min
15
9.4 ¹⁰
8.2
7.7
5.4 ₅
4.9
0
0
13322
5
10
15
20
25
30
35
40
5.7 8.5 11.3 12.0
28.6
32.6
V_S ( V )
Figure 4. Output voltage with tolerances vs. supply voltage
The data transmission from the external unit to the
interface IC is carried out on the same line by varying the
current level. The quiescent current consumption of the
external unit is about 5 to 15 mA. This current level is
interpreted as logic high level at CLL-pin. The external
unit can switch on an additional current of 30 mA,
interpreted by the interface as logic low. The current
changes within approximately 1 ms, sufficient for a
transmission rate of about 60 kBaud, requiring a
transmission bandwidth of about 500 kHz for the current-
monitoring subcircuit and the OCM output. For a good
current transmission behaviour, the dynamic resistance of
W OUTx may not exceed 12 inside the bandwidth range
W (total of 15 for OUTx and RETURN).
The OUTx- voltage can be switched off by
ENABLEx = LOW to reset the external unit and to
reduce power dissipation during fault conditions.
The OUT pins are overtemperature- and short-circuit
protected. A reverse polarity diode at Pin V_S (Pin 4) en-
sures that no current is fed back to the V_Batt-system in the
case of a short between OUTx and V_Batt. A minimum ca-
pacity of 33 nF is required at the pins OUTx .
ENABLE1, ENABLE2
D Low or open circuit applied to ENABLEx switches
the related OUTx and RETURNx off (high imped-
ance). A sink current at Pin OUTx discharges the
capacitive load.
D High applied to ENABLEx switches the related
OUTx and RETURNx on to supply the external unit.
OCM1, OCM2
The output current of OUTx is monitored with a transmis-
sion factor of 0.1 to the OCMx. With a resistor from OCM
W ^{to GND, the current is converted to a voltage. The electri-}
cal characteristics are specified by R_OCM = 750 . The
CLL-current threshold, the OUT-current limitation and
W W ^{the OUT-current detection can be changed by varying}
R_OCM in a range from 500 to 1 k .
The current monitoring enables to detect overcurrent
conditions at OUTx (short circuit to GND or RETURNx)
and to detect low current conditions at OUTx (short cir-
cuit to V_Batt or open load).
The internal pull-down current at the OUTx creates no
OCMx-current. During enable, the minimum voltage at
OCMx is the saturation voltage of an internal NPN-tran-
sistor with typically 0.1 V. The maximum voltage at
OCM is limited by an internal clamping diode to 5.3 V.
CLL1, CLL2
ENABLEx is a microcontroller-compatible input which The current at Pin OUTx is logical evaluated and ready
switches the related output on or off.
to use for a microcontroller input. With this stage, the
TELEFUNKEN Semiconductors
3 (12)
Rev. A1, 21-May-97
Preliminary Information