
M80C286
Table 19. M80C286 Systems Recommended Pull Up Resistor Values
M80C286 Pin and Name
Pullup Value
Purpose
4DS1
Pull S0, S1, and PEACK inactive during M80C286 hold periods
5DS0
20 K
X
g
10%
(Note 1)
6DPEACK
63DREADY
910
X
g
5%
Pull READY inactive within required minimum time (C
L
e
150 pF,
l
R
s
7 mA)
NOTE:
1. Pullup resistors are not required for S0 and S1 when the corresponding pins on the M82C284 are connected to S0 and
S1.
M80286 IN-CIRCUIT EMULATION
CONSIDERATIONS
One of the advantages of using the M80C286 is that
full in-circuit emulation development support is avail-
able
thru
either
the
I
2
ICE
8 MHz/10 MHz or ICE286 for 12.5 MHz designs. To
utilize these powerful tools it is necessary that the
designer be aware of a few minor parametric and
functional differences between the M80C286 and
the in-circuit emulators. The I
2
ICE datasheet (I
2
ICE
Integrated Instrumentation and In-Circuit Emulation
System, order
Y
210469) contains a detailed de-
scription
of
these
design
ICE286 Fact Sheet (
Y
280718) and User’s Guide
(
Y
452317) contain design considerations for the
80286 12.5 MHz microprocessor. It is recommended
that the appropriate document be reviewed by the
80286 system designer to determine whether or not
these differences affect the design.
80286
probe
for
considerations.
The
PACKAGE THERMAL
SPECIFICATIONS
The M80C286 Microprocessor is specified for opera-
tion when case temperature (T
C
) is within the range
of
b
55
§
C–
a
125
§
C. Case temperature, unlike ambi-
ent temperature, is easily measured in any environ-
ment to determine whether the M80C286 Microproc-
essor is within the specified operating range. The
case temperature should be measured at the center
of the top surface of the component.
The maximum ambient temperature (T
A
) allowable
without violating T
C
specifications can be calculated
from the equations shown below. T
J
is the 80C286
junction temperature. P is the power dissipated by
the M80C286.
T
J
e
T
C
a
P
*
i
JC
T
A
e
T
J
b
P
*
i
JA
T
C
e
T
A
a
P
* [
i
JA
b
i
JC
]
Values for
i
JA
and
i
JC
are given in Table 20. Table
21 shows the maximum T
A
allowable (without ex-
ceeding T
C
).
Junction temperature calculations should use an I
CC
value that is measured without external resistive
loads. The external resistive loads dissipate addi-
tional power external to the M80C286 and not on
the die. This increases the resistor temperature, not
the die temperature. The full capacitive load (C
L
e
100 pF) should be applied during the I
CC
measure-
ment.
Table 20. Thermal Resistances (
§
C/W)
Package
i
JC
i
JC
68-Lead PGA
5.5
30
68-Lead CQFP
11
32
NOTE:
The numbers in Table 20 were calculated using an
I
CC
of 150 mA, which is representative of the worst
case I
CC
at T
C
e
125
§
C with the outputs unloaded.
Table 21. Maximum (T
A
)
Package
T
A
(
§
C)
68-Lead PGA
105
68-Lead CQFP
108
40