MC33286DW Freescale Semiconductor, MC33286DW Datasheet - Page 5

• Manufacturer Part Number: MC33286DW
• Manufacturer: Freescale Semiconductor

Specifications of MC33286DW

• Switch Type: High Side
• Power Switch Family: MC33286
• Input Voltage: 1.5 to 3.5V
• Power Switch On Resistance: 25mOhm
• Output Current: 6A
• Number Of Outputs: Dual
• Mounting: Surface Mount
• Supply Current: 20mA
• Package Type: SOIC W
• Operating Temperature (min): -40C
• Operating Temperature Classification: Automotive
• Pin Count: 20
• Lead Free Status / Rohs Status: Not Compliant

automotive applications. In comparison with mechanical
relays, this device offers higher reliability as well as protection
and diagnostic features. It has been designed to be directly
connected to the battery voltage.
connected to the battery will increase, so the MC33286
includes a special input trigger and architecture which allows
to have a very low standby current when the V
12V.
in a single SO20 package. This low power package can be used
because the ON resistance of the switch (35mΩ max at 25°C)
guarantees a low power dissipation (less than 300mW) when
driving two 21Watts lamps. The two chips are internally connected
by die to die wire bonding to allow the transfer of analog and
control information between the two dice.
technology. The two channels of this control chip are totally
symmetrical and independant. It drives the gate of the output
power MOSFET and manages the analog information from the
power MOSFET die to ensure power device protection.
one independent sources plus current sensing cells for open
load detection and current limitation. In addition, a thermal
sensor (diode) is located in the middle of each source to
protect the MC33286 against overtemperature. The drain of
the Power die is connected to the battery voltage by the lead
frame of the package. This lead frame has been especially
developed and has eight pins connected together to the V
These pins are used as the V
path.
Supply Voltage
Figure 4 shows the supply voltage characteristics. The V
(V
2, 5, 6, 15, 16, 19, 20) are not internally connected, so the V
and V
circuit board.
Under Voltage
when one or two sides of the MC33286 are turned on. From
0V to undervoltage level (7V typical), all blocks of the
MC33286 are not totally supplied. The undervoltage threshold
value versus temperature is shown in Figure 2.The under
voltage function allows the turn-off of the output transistor,
because the V
full on state of the output transistor due to an incomplete drive
of the gate. When the V
threshold, the supply current increases due to the charge
pump start up and MOSFET driver activation.
Reverse Battery Protection
in a reverse direction from the source region to drain region of
both of the MosFets through the body diode. The limitation is
then the temperature reached by the junction, which is linked
to the thermal impedance from the junction to the ambiant.
General Information
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This device is a dual high side power switch dedicated for
In the future, the number of electronic switches directly
The MC33286 concept uses a dual chip approach packaged
The two chips are the Control and Power dice.
The
The Power chip uses the HDTMOS3 technology. It has
The MC33286 can be directly connected to the V
Figure 4 also shows the supply voltage characteristic
When a negative battery voltage arises, the current flows
of Control die, pin 10) and V
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Control
have to be connected externally by the printed
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voltage will be not enough to guarantee the
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FUNCTIONAL DESCRIPTION
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Input Trigger
the device to have less than 0.5µA typical standby current.
When the input level is below 1.5V, the circuit is in sleep mode
(see Figure 4).
Status Output
level, so an external pull-up resistor is required to read the
status information.
temperature information. The output short-circuit, current
limitation and V
pin. But an output short-circuit to Gnd will be detected by an
overtemperature because the total power dissipation of the
device will make it reach the thermal detection.
Open Load Function
open load detection). An amplifier measures the differential volt-
age between V
25°C.
and the open load circuitry will detect it and will pull down the sta-
tus output. If the open load condition is present before the device
turn-on, the status will be pulled down after a delay due to the rise
time of the output.
Overcurrent Function (High Current Limitation)
typical when outputs are loaded (Vout > 1V) . A 21 Watts lamp
has a nominal current of about 2 amp and at turn on, the
MC33286 has to drive a peak current of about 12A, as the
lamp inrush current is about six times the nominal DC current.
A standard current limitation set up at 30A will not being
activated during the inrush current of one lamp but will protect
the circuit against overcurrent. Figure 3 shows the overcurrent
threshold versus temperature.
would be 30A x 14V = 420 Watts if only the overcurrent
limitation exists. The thermal protection will be activated and
switch the device off. Nevertheless the peak power
dissipation and energy is quite high.
implemented and is activated when the output voltage is lower
than about 1V . As shown in the Figure 5, the low current
limitation decreases with temperature. In the case of a short
circuit, the power dissipated in the device decreases with time
due to the decay of the current limitation with temperature.
Overtemperature Function
located in the middle of each output power HDTMOS
transistor. The sensor is a diode connected to V
power die. The diode forward voltage varies of -2mV/°C. So,
by measuring the diode voltage the power output MOSFET
temperature is monitored. This diode voltage information is
transferred to the control die and compared to a reference
voltage generated from the band gap reference generator.
When the temperature reaches the overtemp threshold, the
circuit is turned off. As the input voltage is still high, the circuit
is not in wake mode but the current consumption decreases
due to the turn-off of the charge pump. The overtemperature
Short Circuit Protection (Low Current Limitation)
The MC33286 has a special input trigger circuitry allowing
The output status is an open drain structure, active at low
The status indicates the open load and the over
The open load detection is active during the ON phase (Hot
An open load condition will create a voltage lower than 12mV
The device incorporates a current limitation at 30 Amps
During a hard short-circuit to Gnd, the power dissipation
Therefore,
The overtemperature function uses a thermal sensor
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a
undervoltage are not reported on the status
and V
short
out
(this value is typically 400mA) at
circuit
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been
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