at84ad001b ATMEL Corporation, at84ad001b Datasheet - Page 56

• Manufacturer Part Number: at84ad001b
• Description: Dual 8-bit 1 Gsps Adc
• Manufacturer: ATMEL Corporation

Thermal Characteristics
Simplified Thermal
Model for LQFP 144
20 x 20 x 1.4 mm
Figure 62. Simplified Thermal Model for LQFP Package
Note:
Thermal Resistance from
Junction to Bottom of Leads
Thermal Resistance from
Junction to Top of Case
Thermal Resistance from
Junction to Bottom of Case
Thermal Resistance from
Junction to Bottom of Air Gap
56
Assumptions:
Die 5.0 x 5.0 = 25 mm
40 µm thick Epoxy/Ag glue
The above are typical values with an assumption of uniform power dissipation over 2.5 x 2.5 mm
AT84AD001B
355 µm silicon die
25 mm
λ = 0.95W/cm/˚C
Resin bottom
λ = 0.007W/cm/˚C
40 µm Epoxy/Ag glue
λ = 0.02 W/cm/˚C
Copper paddle
λ = 2.5W/cm/˚C
Aluminium paddle
λ = 0.75W/cm/˚C
2
2
The following model has been extracted from the ANSYS FEM simulations.
Assumptions: no air, no convection and no board.
Assumptions: no air, no convection and no board.
The thermal resistance from the junction to the bottom of the leads is 15.2° C/W typical.
Assumptions: no air, no convection and no board.
The thermal resistance from the junction to the top of the case is 8.3° C/W typical.
Assumptions: no air, no convection and no board.
The thermal resistance from the junction to the bottom of the case is 6.4° C/W typical.
The thermal resistance from the junction to the bottom of the air gap (bottom of pack-
age) is 17.9° C/W typical.
Package bottom
connected to:
(user dependent)
Silicon Junction
Package
bottom
0.1˚C/watt
0.1˚C/watt
0.6˚C/watt
1.4˚C/watt
4.3˚C/watt
Aluminium paddle
100 µm thermal grease gap diamater 12 mm
6.1˚C/watt
100 µm air gap
11.4˚C/watt
1.5˚C/watt
λ = 0.007W/cm/˚C
λ = 0.007W/cm/˚C
8.3˚C/watt
1.5˚C/watt
Resin
Resin
λ = 0.00027W/cm/˚C
λ = 0.01W/cm/˚C
Copper alloy leadframe
5.5˚C/watt
Package top
λ = 25W/cm/˚C
2
of the top surface of the die.
Top of user board
Leads tip
2153C–BDC–04/04