PXN20 Datasheet, PDF (27/60 Pages) Freescale Semiconductor, Inc – PXN20 Microcontroller

Electrical characteristics
8 _{VDDEx are separate power segments and may be powered independently with no differential voltage constraints between the}
power segments.
9 _{AC signal over and undershoot of the input voltages of up to ±2.0 V is permitted for a cumulative duration of 60 hours over the}
complete lifetime of the device (injection current does not need to be limited for this duration).
10 _{Internal structures will hold the input voltage above –1.0 V if the injection current limit of 2 mA is met.}
11 _{Internal structures hold the input voltage below this maximum voltage on all pads powered by VDDE supplies, if the maximum}
injection current specification is met (25 mA for all pins) and V_DDE is within Operating Voltage specifications.
12 _{Total injection current for all pins (including both digital and analog) must not exceed 25 mA.}
13 _{Total injection current for all analog input pins must not exceed 15 mA.}
14 _{Solder profile per CDF-AEC-Q100.}
15 _{Moisture sensitivity per JEDEC test method A112.}
4.2 Thermal characteristics
Table 6. Thermal characteristics
Spec
Characteristic
Symbol Unit
Value
208 MAPBGA 256 MAPBGA
1 Junction to Ambient^{1, 2}
Natural Convection
(Single layer board)
R_JA
°C/W
39
39
2 Junction to Ambient^{1, 3}
Natural Convection
(Four layer board 2s2p)
R_JA
°C/W
24
24
3 Junction to Ambient^{1, 3}
(@200 ft./min., Single layer board)
R_JMA °C/W
31
31
4 Junction to Ambient^{1, 3}
R_JMA °C/W
20
20
(@200 ft./min., Four layer board 2s2p)
5 Junction to Board⁴
6 Junction to Case⁵
7 Junction to Package Top⁶
Natural Convection
R_JB
°C/W
13
13
R_JC
°C/W
6
6
_JT
°C/W
2
2
1 _{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.
2 _{Per SEMI G38-87 and JEDEC JESD51-2 with the single layer board horizontal.}
3 _{Per JEDEC JESD51-6 with the board horizontal.}
4 _{Thermal resistance between the die and the printed circuit board per JEDEC JESD51-8. Board temperature is measured on}
the top surface of the board near the package.
5 _{Indicates the average thermal resistance between the die and the case top surface as measured by the cold plate method (MIL}
SPEC-883 Method 1012.1) with the cold plate temperature used for the case temperature.
6 _{Thermal characterization parameter indicating the temperature difference between package top and the junction temperature}
per JEDEC JESD51-2.
4.2.1 General notes for specifications at maximum junction temperature
An estimation of the chip junction temperature, T_J, can be obtained from the equation:
T_J = T_A + (R_JA  P_D)
Eqn. 1
PXN20 Microcontroller Data Sheet, Rev. 1
Freescale Semiconductor
27