MC33981BPNA Freescale, MC33981BPNA Datasheet - Page 14

• Manufacturer Part Number: MC33981BPNA
• Manufacturer: Freescale

Specifications of MC33981BPNA

• Switch Type: High Side
• Power Switch Family: MC33981B
• Power Switch On Resistance: 6mOhm
• Output Current: 40A
• Number Of Outputs: Single
• Mounting: Surface Mount
• Supply Current: 10mA
• Package Type: Power QFN
• Operating Temperature (min): -40C
• Operating Temperature Classification: Automotive
• Pin Count: 16
• Lead Free Status / RoHS Status: Compliant

directly but rather its effects on the low side MOSFET. When
V
current source is disconnected and OCLS goes to 0V. The
GLS pin and the OCLS pin are reset (and the fault is
delatched) by a logic [0] at the INLS pin for at least t
Figure 13
overload on Low Side Gate driver.
its internal current source sets the V
the external resistance, the protection level can be adjusted
depending on low side characteristics. A 33 kΩ resistor gives
a V
drain of the low side (DLS pin) and the 33981 ground (GND
pin). For this reason it is key that the low side source, the
33981 ground, and the external resistance ground
connection are connected together in order to prevent false
error detection due to ground shifts.
on DLS must be used to detect a higher voltage across the
low side.
CONFIGURATION
the internal MOSFET and the external low side MOSFET.
With the CONF pin at 0V, the two MOSFETs can be
independently controlled. A load can be placed between the
high side and the low side.
on at the same time. They are in half-bridge configuration as
shown in the simplified application diagram on
INHS and INLS are at 5.0 V at the same time, INHS has
priority and OUT will be at V
to 0 V with INLS at 5.0 V, GLS will go to high state as soon
as the V
typically. A half-bridge application could consist in sending
PWM signal to the INHS pin and 5.0 V to the INLS pin with
the CONF pin at 5.0 V.
page 1
and INLS pins are at 5.0 V. When INHS is at 5.0 V, current is
flowing in the motor. When INHS goes to 0 V, the load current
recirculates in the external low side.
BOOTSTRAP SUPPLY
capacitor through the V
the application of power to the device to charge the bootstrap
capacitor.
internal charge pump allows continuous MOSFET drive.
14
33981
FUNCTIONAL DEVICE OPERATION
PROTECTION AND DIAGNOSTIC FEATURES
DLS
When connected to an external resistor, the OCLS pin with
This protection circuitry measures the voltage between the
The maximum OCLS voltage being 4.0 V, a resistor bridge
The CONF pin manages the cross-conduction between
With the CONF pin at 5.0 V, the two MOSFETs cannot be
Figure
Bootstrap supply provides current to charge the bootstrap
DS
> V
level of 3.3 V typical.
with a DC motor and external low side. The CONF
GS
OCLS
20, illustrates the simplified application diagram on
and
A typical value for this capacitor is 100 nF. An
of the internal MOSFET is lower than 2.0 V
, the GLS pin goes to 0V and the OCLS internal
Figure 14
PWR
illustrate the behavior in case of
PWR
pin. A short time is required after
. If INHS changes from 5.0 V
OCLS
level. By changing
page
RST(DIAG)
1. If
.
When the device is in the sleep mode, this bootstrap supply
is off to minimize current consumption.
HIGH SIDE GATE DRIVER
voltage to the gate of the MOSFET. The driver circuit has a
low-impedance drive to ensure that the MOSFET remains
OFF in the presence of fast falling dV/dt transients on the
OUT pin.
supply and the C
drive the device. The voltage across this capacitor is limited
to about 13 V typical.
GND is used to control the slew rate at the OUT pin.
and
capacitors.
LOW SIDE GATE DRIVER
a standard MOSFET with an R
frequency up to 60 kHz. The V
12 V typically to protect the gate of the MOSFET. The GLS
pin is protected against short by a local over temperature
sensor.
THERMAL FEEDBACK
provides a value in inverse proportion to the temperature of
the GND flag (pin 13). The controlling microcontroller can
“read” the temperature proportional voltage with its analog-
to-digital converter (ADC). This can be used to provide real-
time monitoring of the PC board temperature to optimize the
motor speed and to protect the whole electronic system.
TEMP pin value is V
coefficient of
REVERSE BATTERY
voltage as low as -16 V. Under these conditions, the output’s
gate is enhanced to decrease device power dissipation. No
additional passive components are required. The 33981
survives these conditions until the maximum junction rating is
reached.
a direct current passes through the external freewheeling
diode and the internal high side.
line. The proposed solution is an external N-channel low side
with its gate tied to battery voltage through a resistor. A high
side in the V
The high side gate driver switches the bootstrap capacitor
This bootstrap capacitor connected between the power
An external capacitor connected between pins SR and
The low side control circuitry is PWM capable. It can drive
The 33981 has an analog feedback output (TEMP pin) that
The 33981 survives the application of reverse battery
In the case of reverse battery in a half-bridge application,
As
Figure 10
Figure 11
PWR
DT
give V
shows, it is essential to protect this power
FEED
BOOT
line could be another solution.
OUT
TFEED
.
Analog Integrated Circuit Device Data
pin provides the high pulse current to
rise and fall time versus different SR
with a negative temperature
DS(ON)
GS
is internally clamped at
Freescale Semiconductor
as low as 10.0 mΩ at a
Figure 9