MC33486 Motorola, MC33486 Datasheet - Page 7

• Manufacturer Part Number: MC33486
• Description: Dual High Side Switch
• Manufacturer: Motorola

Overtemperature Protection
The DHSB incorporates over-temperature protection. Over-
temperature detection occurs when an internal high side is in
the on state. When an over-temperature condition occurs,
both outputs are affected. Both outputs are turned off to
protect the DHSB from damage (Low sides ON). The
overtemperature protection circuitry incorporates hysteresis.
Overtemperature fault condition is reported on the status
output.
High side overcurrent protection
35A typical. When this limit is reached due to an overload
condition or a short to ground, the faulty output is tri-stated. To
clear the fault the input (Inx) line needs to return low then on
the next high transition the output will be enabled.
Low side block
Channel power MOSFET’s. The low side control circuitry is
PWM capable and protects the Low side MOSFETS in case of
overcurrent (short to Vbat). This information is reported on the
status output.
to protect the gates of the Low Sides.
driven by the high side. The low side Gate driver’s will only
turn on when the Drain voltage (same connection as OUT1 or
2) of the internal high sides is less than 2V, which prevent any
cross-conduction in the bridge.
Low Side Overcurrent Protection
protection does not measure the current , but measures the
effect of current on the low side through a condition : Vgs >
4.3V and Vds >2V. When this set of conditions occur for at
least 8us (blanking time), both outputs OUT1 and OUT2 are
tri-stated. The full bridge is tri-stated to prevent the motor for
running in case of short to Vbat.
ground pin, it is essential that the low side source are
connected to this same ground, in order to prevent false
overcurrent detection due to ground shifts.
Package
mount
performances, and high current capabilities. It offers 10 pins
on each package sides, and one additional connection which
is the package heat sink (called pin 21). The heat sink acts as
the device power Vbat connection.
package indended to be soldered directly on the Printed
Circuit Board.
JESD22-A113-B and J-STD-020A with the reflow conditions
applicable for packages with thickness above 2.5mm :
Soldering Information
This device incorporates a current shutdown threshold of
This information is reported on the status output.
The low side block has control circuitry for two external N-
The low side Gate controls are clamped at14V maximum
During normal operation, the outputs OUT1 and OUT2 are
Unlike the high side overcurrent circuitry, this overcurrent
As Vgs and Vds are measured in respect to the DHSB’s
The high side block is assembled into a power surface
This device is packaged in a Surface Mount Power
This device was qualified according to JEDEC standards
Convection 220°C +5/-0°C
VPR 215-219°C
IR / Convection 220°C +5/-0°C
package.
This
package
Dual High Side Switch for H-Bridge Automotive Applications
Freescale Semiconductor, Inc.
offers
For More Information On This Product,
high
Go to: www.freescale.com
DEVICE DESCRIPTION
thermal
MC33486
should not exceed 220°C (+5°C/-0°C). The time at maximum
temperature should range from 10 to 40s max.
maximum. The junction to ambient thermal resistance is
dependant on the mounting technology, and if an additional
heat sink is used. One of the most commonly used mounting
technique consists of using the printed circuit board and the
copper lines as heat sink.
has a total of 10cm
on the top side and 7.5 cm
ambient of 25°C/W can be achieved. This value being splitted
into :
thicker copper metal, higher number of thermal via from top to
bottom side pcb and the use of additional thermal via from the
circuit board to the module case.
Thermal model
mounted on a printed circuit board can be splitted into two
main parts: junction to case and case to ambient resistances.
The maximum peak temperature during the soldering process
Figure 3. .Printed Board Layout Example (not to scale)
Power Dissipation)
Figure 4.
(1.0A=1W of
Thermal Management
The junction to case thermal resistance is 2°C/W
Figure 2 is an example of printed circuit board layout. It
With the above layout, thermal resistance junction to
. junction to case : Rthjc = 2°C/W
. case to ambient : Rthca = 23 °C/W.
Lower value can be reached with the help of larger and
The junction to ambient thermal resistance of the circuit
A simplified steady state model is shown in figure 3 below.
top to down
Power (W)
Bottom side pcb
HSOP20
Thermal
side pcb
via from
8 cm
Simplified Thermal Model (Electrical Equivalent)
2
2
additional copper on two sides (2.5 cm
Rthjc
2
on the down side).
external pcb (4x4 cm)
Switch
Ambient Temp Node
(1.0V=1°C Ambient Temperature)
Case Temp Node
(1.0Ω=1°C/W)
Surface Temperature)
Junction Temp Node
(Volts represent Die
Rthca
Top side pcb
2 cm
2
2
7