mc33198dr2 Freescale Semiconductor, Inc, mc33198dr2 Datasheet - Page 11

• Manufacturer Part Number: mc33198dr2
• Description: Automotive High-side Tmos Driver
• Manufacturer: Freescale Semiconductor, Inc

automotive applications. It is used in conjunction with an
external power MOSFET for high side drive applications. The
device can drive and protect a large variety of MOSFETs.
The device has a CMOS compatible input control, charge
pump to drive the MOSFET gate, and fault detection circuitry
based on programmable V
loads. It also includes a programmable timer function to
eliminate undesired switch off due to in rush currents, and a
status pin which reports the output status of both on and off
MOSFET states. The device uses few external components,
and offers an economical solution to large current high side
switches. It also has PWM capability up to 1kHz.
POWER SUPPLY
designed with a 60V technology, making it able to sustain up
to 60V transient pulses. In the off state, with pin 7 low, the
supply current can be up to 5.0mA, and in operation, pin 7
high, the current up to 25mA. The device has an
undervoltage detection and shutdown near 7.0V. Below this
value the MOSFET is turned off. There is also a 25V
overvoltage detection which switches off the output pin 4 to
protect both the MOSFET and the load when V
than 25V.
CHARGE PUMP
an internal capacitor and is connected at Gate pin 4. To
prevent oscillation, a serial resistor can be added. The charge
pump is able to charge a 25nF capacitor in less than 1ms.
This allows the MC33198 to have a rapid response time and
to drive the external TMOS gate very quickly, allowing fast
switching on of the load. The device has an internal 15V
zener diode between pin 4 and 1, to clamp the Gate-to-
Source voltage and protect the MOSFET gate oxide from
destruction. See
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BAND GAP AND REFERENCE CURRENTS
which generates all the internal thresholds. This band gap is
also used to generate internal reference currents necessary
for proper operation of the device. These currents are :
100mA and 10mA).
voltage and internal resistor. Their accuracy and variability is
approximately +-25% over the full temperature and voltage
range. In addition, a passive pull down current of 5.0mA
Analog Integrated Circuit Device Data
Freescale Semiconductor
for details.
The MC33198 is a high side TMOS driver, dedicated to
The MC33198 can be supplied from the battery line. It is
The device incorporates a self running charge pump with
The MC33198 has an internal band gap reference voltage
Pin 2 : Drain current (typically 80mA).
Pin 4 : High and low gate discharge currents (typically
Pin 8 : Timer charge current (10mA typical).
All these currents are derived from the same reference
Dynamic Electrical Characteristics on page
DS
monitoring to detect shorted
FUNCTIONAL DESCRIPTION
CC
is higher
INTRODUCTION
maintains the gate of the MOSFET below 0.9V when the
device has no supply, ensuring that the MOSFET remains off.
This passive pulldown current is operating even if device
VCC (pin 5) is not powered up.
INPUT CIRCUITRY
can be directly connected to a microcontroller. The input
current is determined by an internal pull down resistor,
typically 36kW. A hysteresis of 0.8 V minimum is present at
this input.
OUTPUT STATUS
collector structure. This pin is used to report the MOSFET
overload condition or the LOAD status when the MOSFET is
off. The device Pin 1 (Source) is compared to a
programmable threshold at Pin 2, in both the on and off state
of the MOSFET. This allows the detection of the MOSFET
over V
and the load short to VBAT monitoring, when the MOSFET is
in the off state. This status pin is normally connected to a pull-
up resistor and a micro input, and can drive up to 1.0mA.
TIMER
external capacitor to create a delay between the overload
detection and the shutdown of the MOSFET. In case of over
load, the internal current source pin 8 will charge the
capacitor. When the voltage at pin 8 reaches the 5.5V
threshold, the internal C3 comparator will be triggered and
switch off the output to protect the MOSFET. The fault and
the MOSFET turn off condition are latched and are reset by
switching the input off and on. The delay between the
overload detection and actual MOSFET turn off is used to
allow a temporary overload which will prevent the system
from switching off during possible inrush currents or
transients.
MOSFET PROTECTION AND OUTPUT VOLTAGE
MONITORING
source voltage and compare it to a predetermined threshold.
This threshold is programmable, using the internal reference
current of 80mA and an external resistor connected at pin 2
(DRN). The device can monitor the output load voltage, as
well as protect the MOSFET in case of overload.
MOSFET itself depending on the load to be driven and the
thermal capability of the MOSFET. In practice, the maximum
acceptable V
based upon the MOSFET maximum power dissipation.
The Input pin (pin 7) of the device is CMOS compatible and
The device has a status output (pin 6) which has an open
The Timer pin (pin 8) is used in conjunction with an
The MC33198 has the ability to sense the output MOSFET
The overload detection threshold must be adapted to the
DS
or over load conditions when the MOSFET is on
DS
of the MOSFET should be determined and
FUNCTIONAL DESCRIPTION
INTRODUCTION
33198
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