Freescale Semiconductor 56F8122 - Manual (Page 101)

General Characteristics
56F8322 Technical Data, Rev. 10.0
Freescale Semiconductor 101
Preliminary
1. Theta-JA determined on 2s2p test boards is frequently lower than would be observed in an application. Determined on 2s2p ther-
mal test board.
2. Junction to ambient thermal resistance, Theta-JA (R
qJA
), was simulated to be equivalent to the JEDEC specification JESD51-2
in a horizontal configuration in natural convection. Theta-JA was also simulated on a thermal test board with two internal planes
(2s2p, where “s” is the number of signal layers and “p” is the number of planes) per JESD51-6 and JESD51-7. The correct name
for Theta-JA for forced convection or with the non-single layer boards is Theta-JMA.
3. Junction to case thermal resistance, Theta-JC (R
qJC
), was simulated to be equivalent to the measured values using the cold
plate technique with the cold plate temperature used as the "case" temperature. The basic cold plate measurement technique is
described by MIL-STD 883D, Method 1012.1. This is the correct thermal metric to use to calculate thermal performance when
the package is being used with a heat sink.
4. Thermal Characterization Parameter, Psi-JT (Y
JT
), is the "resistance" from junction to reference point thermocouple on top cen-
ter of case as defined in JESD51-2. Y
JT
is a useful value to use to estimate junction temperature in steady-state customer envi-
ronments.
5. Junction temperature is a function of on-chip power dissipation, package thermal resistance, mounting site (board) temperature,
ambient temperature, air flow, power dissipation of other components on the board, and board thermal resistance.
6. See Section 12.1 for more details on thermal design considerations.
Table 10-2 56F8322/56F8122 ElectroStatic Discharge (ESD) Protection
Characteristic Min Typ Max Unit
ESD for Human Body Model (HBM) 2000 — — V
ESD for Machine Model (MM) 200 — — V
ESD for Charge Device Model (CDM) 500 — — V
Table 10-3 Thermal Characteristics
6
Characteristic Comments Symbol
Value
Unit Notes
48-pin LQFP
Junction to ambient
Natural Convection
R θ JA
41 °C/W 2
Junction to ambient (@1m/sec) R θ
JMA
34 °C/W 2
Junction to ambient
Natural Convection Four layer board
(2s2p) R θ JMA
(2s2p)
34 °C/W 1,2
Junction to ambient (@1m/sec) Four layer board
(2s2p) R θ JMA
29 °C/W 1,2
Junction to case R θ JC
8 °C/W 3
Junction to center of case Ψ
JT
2 °C/W 4, 5
I/O pin power dissipation P
I/O
User-determined W
Power dissipation P
D
P
D
= (I
DD
x V
DD
+ P
I/O
) W
Maximum allowed P
D
P
DMAX
(TJ - TA) /
θ
JA °C