Vishay Siliconix

Si4670DY_RC

Document Number: 69737

Revision: 02-Oct-07

www.vishay.com

1

R-C Thermal Model Parameters

DESCRIPTION

The parametric values in the R-C thermal model have

been derived using curve-fitting techniques. These

techniques are described in "A Simple Method of

Generating Thermal Models for a Power MOSFET"[1].

When implemented in P-Spice, these values have

matching characteristic curves to the Single Pulse

Transient

Thermal

Impedance

curves

for

the

MOSFET.

R-C values for the electrical circuit in the Foster/Tank

and Cauer/Filter configurations are included.

Note:

For a detailed explanation of implementing these values in

P-SPICE, refer to Application Note AN609 Thermal Simulations Of

Power MOSFETs on P-SPICE Platform.

R-C THERMAL MODEL FOR TANK CONFIGURATION

This document is intended as a SPICE modeling guideline and does not constitute a commercial product data sheet. Designers should refer to the appropriate data

sheet of the same number for guaranteed specification limits.

R-C VALUES FOR TANK CONFIGURATION

Thermal Resistance (°C/W)

Junction to

Ambient Ch1

Ambient Ch2

Case

Foot Ch1

Foot Ch2

RT1

6.9442

6.9442

N/A

11.6583

11.6583

RT2

30.0404

30.0404

N/A

3.6731

3.6731

RT3

25.8463

25.8463

N/A

8.9996

8.9996

RT4

47.1691

46.1691

N/A

19.6690

19.6690

Thermal Capacitance (Joules/°C)

Junction to

Ambient Ch1

Ambient Ch2

Case

Foot Ch1

Foot Ch2

CT1

386.3454 u

386.3454 u

N/A

2.2210 m

2.2210 m

CT2

57.6804 m

57.6804 m

N/A

170.7109 u

170.7109 u

CT3

6.9241 m

6.9241 m

N/A

180.0765 m

180.0765 m

CT4

1.1640

1.1640

N/A

11.0677 m

11.0677 m