FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
This paragraph is boilerplate - you may add to it but, can not change wording. You may change numeric values
An external resistor must be connected to the CUR R
terminal and then tied to a microcontroller A/D input for
analog voltage measurement. The CUR R terminal is
internally clamped to protect the MCU A/D input.
Top side pcb
Down side pcb
2
2
2 cm
8 cm
Warning Lamp Driver
The warning lamp driver is a 3.2 Ω RDSON maximum
high-side MOSFET to control the 1.2 W dashboard warning
lamp. This output is current limited and thermally
HSOP20
protected-activated only in the warning mode. It is turned on
by activation of both right and left inputs (IN1 and IN2).
Thermal
via from
top to down
side pcb
Package
The device is assembled into a power surface mount
package. This package offers high thermal performances
and high current capabilities. It offers 10 terminals on each
package sides and an additional terminal which is the
package heat sink , called terminal 21. The heak sink acts as
the MC33288 power VBAT connection.
external pcb (4x4 cm)
Figure 3. Printed Board Layout Example (not to scale)
Figure 1 shows an example of printed circuit board layout.
It has a total of 10 cm2 additional copper on two sides (2.5
cm2 on the top side and 7.5 cm2 on the down side).
With the above layout, thermal resistance junction to
ambient of 25°C/W can be achieved, this value being split
into:
Soldering Information
This device is packaged in a Surface Mount Power
package indended to be soldered directly on the Printed
Circuit Board.
• junction to case : RθJC1 = RθJC2 = 2°C/W
• case to ambient : RθCA = 23°C/W
This device was qualified according to JEDEC standards
JESD22-A113-B and J-STD-020A with the reflow conditions
applicable for packages with thickness above 2.5 mm:
Lower value can be reached with the help of larger and
thicker copper metal, higher number of thermal via from top
to down side pcb and the use of additional thermal via from
the circuit board to the module case.
Convection 220°C +5/-0°C
VPR 215-219°C
IR / Convection 220°C +5/-0°C
Steady State Thermal Model
The maximum peak temperature during the soldering
process should not exceed 220°C (+5°C/-0°C). The time at
maximum temperature should range from 10 to 40s
maximum.
The junction to ambient thermal resistance of the circuit
mounted on a printed circuit board can be split into two main
parts: junction to case and case to ambient resistances.
A simplified steady state model is shown in Figure 2.
Thermal Management
Chan 1 Junction
Temp Node
The junction to case thermal resistance is 2°C/W
maximum. The junction to ambient thermal resistance is
dependent on the mounting technology and the addition of
heat sink. One of the most commonly used mounting
techniques consists of using the printed circuit board and the
copper lines as heat sink.
(Volts represent Die
Temp Node
Chan 2 Junction
Surface Temperature)
Chan 1
Chan 2
Switch
Switch
R
R
θJC1
θJC2
2°C/W
2°C/W
Chan 2
Power (W)
Chan 1
Power (W)
Case Temp Node
(1.0A=1W of
Power Dissipation)
Rthca
(1.0Ω=1°C/W)
25°C/W
Ambient Temp Node
AmbientTemperature
(1.0V=1°C)
Figure 4. Simplified Thermal Model (Electrical
Equivalent)
33288
Analog Integrated Circuit Device Data
Freescale Semiconductor
9
FREESCALE [ Freescale ]
