Analog Integrated Circuit Device Data

Freescale Semiconductor

9

33288

FUNCTIONAL DEVICE OPERATION

OPERATIONAL MODES

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.

Warning Lamp Driver

The warning lamp driver is a 3.2

Ω R

high-side MOSFET to control the 1.2 W dashboard warning

lamp. This output is current limited and thermally

protected-activated only in the warning mode. It is turned on

by activation of both right and left inputs (IN1 and IN2).

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

Soldering Information

This device is packaged in a Surface Mount Power

package indended to be soldered directly on the Printed

Circuit Board.

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:

Convection 220°C +5/-0°C

VPR 215-219°C

IR / Convection 220°C +5/-0°C

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.

Thermal Management

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.

Figure 3. Printed Board Layout Example (not to scale)

Figure 1 shows an example of printed circuit board layout.

With the above layout, thermal resistance junction to

ambient of 25

°C/W can be achieved, this value being split

into:

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.

Steady State Thermal Model

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.

Figure 4. Simplified Thermal Model (Electrical

Equivalent)

Down side pcb

Top side pcb

HSOP20

external pcb (4x4 cm)

Thermal

via from

top to down

side pcb

Rthca

Chan 1 Junction

Ambient Temp Node

Chan 2

Case Temp Node

Chan 2 Junction

Temp Node

Temp Node

Chan 1

Switch

Chan 2

Switch

Power (W)

Chan 1

Power (W)

(1.0A=1W of

(1.0V=1

°C)

(Volts represent Die

Surface Temperature)

(1.0

Ω=1°C/W)

Power Dissipation)

2°C/W

2°C/W

25°C/W

AmbientTemperature

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