MC33362

6

MOTOROLA ANALOG IC DEVICE DATA

0

100

L, LENGTH OF COPPER (mm)

PD(max) for TA = 50°C

R

θJA

90

70

60

80

50

10

20

30

40

50

2.8

2.4

1.6

1.2

2.0

0.8

0.4

0

40

30

0

0

Graphs represent symmetrical layout

3.0 mm

Printed circuit board heatsink example

L

L

100

80

60

40

20

10

20

30

40

50

L, LENGTH OF COPPER (mm)

5.0

4.0

3.0

2.0

1.0

0

PD(max) for TA = 70°C

2.0 oz

Copper

R

θJA

Graphs represent symmetrical layout

3.0 mm

L

L

2.0 oz

Copper

Printed circuit board heatsink example

Figure 15. DW Suffix (SOP–16L) Thermal Resistance and

Maximum Power Dissipation versus P.C.B. Copper Length

Figure 16. P Suffix (DIP–16) Thermal Resistance and

Maximum Power Dissipation versus P.C.B. Copper Length

PIN FUNCTION DESCRIPTION

Pin

Function

Description

1

Startup Input

This pin connects directly to the rectified ac line voltage source. Internally Pin 1 is tied to the drain

of a high voltage startup MOSFET. During startup, the MOSFET supplies internal bias, and charges

2

–

This pin has been omitted for increased spacing between the rectified AC line voltage on Pin 1 and

3

VCC

This is the positive supply voltage input. During startup, power is supplied to this input from Pin 1.

When VCC reaches the UVLO upper threshold, the startup MOSFET turns off and power is supplied

from an auxiliary transformer winding.

4, 5, 12, 13

Ground

These pins are the control circuit grounds. They are part of the IC lead frame and provide a thermal

path from the die to the printed circuit board.

6

Resistor RT connects from this pin to ground. The value selected will program the Current Limit

Comparator threshold and affect the Oscillator frequency.

7

Capacitor CT connects from this pin to ground. The value selected, in conjunction with resistor RT,

programs the Oscillator frequency.

8

Regulator Output

This 6.5 V output is available for biasing external circuitry. It requires an external bypass capacitor

of at least 1.0

µF for stability.

9

Compensation

This pin is the Error Amplifier output and is made available for loop compensation. It can be used as

an input to directly control the PWM Comparator.

10

Voltage Feedback

Input

This is the inverting input of the Error Amplifier. It has a 2.6 V threshold and normally connects

through a resistor divider to the converter output, or to a voltage that represents the converter

output.

11

Overvoltage

Protection Input

This input provides runaway output voltage protection due to an external component or connection

failure in the control loop feedback signal path. It has a 2.6 V threshold and normally connects

through a resistor divider to the converter output, or to a voltage that represents the converter

output.

14, 15

–

These pins have been omitted for increased spacing between the high voltages present on the

Power Switch Drain, and the ground potential on Pins 12 and 13.

16

Power Switch

Drain

This pin is designed to directly drive the converter transformer and is capable of switching a

maximum of 500 V and 2.0 A.