WC32P020-XXM Datasheet, PDF (6/14 Pages) White Electronic Designs Corporation – 16 32-Bit General-Purpose Data and Address Registers

White Electronic Designs
WC32P020-XXM
MAXIMUM RATINGS
Symbol
VCC
VI
PDMAX
TCASE
TCASE
TSTG
TJ
Parameter
Supply voltage
Input voltage
Max Power dissipation
Operating temperature (Mil.)
Operating temperature (Ind.)
Storage temperature
Junction temperature
Min Max Unit
-0.3 +7.0
V
-0.3 +7.0
V
2.0
W
-55 +125 °C
-40
+85
°C
-55 +150 °C
+160 °C
Thermal Characteristics
(with no heat sink or airflow)
Characteristic
Symbol Value Rating
Thermal Resistance — Junction to Ambient
PGA Package
CQFP Package
θJA
°C/W
26
46
Thermal Resistance — Junction to Case
PGA Package
CQFP Package
θJC
°C/W
3
15
POWER CONSIDERATIONS
The average chip junction temperature, TJ, in °C can be
obtained from:
TJ = TA + (PD • θJA)
(1)
where:
TA = Ambient Temperature, °C
qJA = Package Thermal Resistance, Junction-to-
Ambient, °C/W
PD = PINT+PI/O
PINT = ICC x VCC, Watts-Chip Internal Power
PI/O = Power Dissipation on Input and Output
Pins-User Determined
For most applications, PI/O < PlNT and can be neglected.
The following is an approximate relationship between PD
and TJ (if PI/O is neglected ):
PD = KÞ(TJ + 273°C)
(2)
θJC is device related and cannot be influenced by the user.
However, θCA is user dependent and can be minimized
by such thermal management techniques as heat sinks,
ambient air cooling, and thermal convection. Thus,
good thermal management on the part of the user can
significantly reduce θCA so that θJA approximately equals
θJC. Substitution of θJC for θJA in equation (1) will result in
a lower semiconductor junction temperature.
Solving equations (1) and (2) for K gives:
K = PD • (TA + 273°C) + qJA • PD2
(3)
where K is a constant pertaining to the particular part. K
can be determined from equation (3) by measuring PD
(at equilibrium) for a known TA. Using this value of K, the
values of PD and TJ can be obtained by solving equations
(1) and (2) iteratively for any value of TA.
The total thermal resistance of a package (θJA) can be
separated into two components, θJC and θCA, representing
the barrier to heat flow from the semiconductor junction
to the package (case) surface (θJC) and from the case to
the outside ambient (qCA). These terms are related by the
equation:
θJA = θJC + θCA
(4)
White Electronic Designs Corp. reserves the right to change products or specifications without notice.
December 2002
Rev. 2
6
White Electronic Designs Corporation • [phone] • www.wedc.com