Tandy 2000 Service Manual page 588

iru
8251
A
ABSOLUTE MAXIMUM RATINGS-
Ambient Temperature Under
Bias
..0'C
to
70'C
Storage
Temperature
65'C
to
*
150'C
Voltage
On
Any
Pin
With
Respect
To
Ground
0
5V
to
+
7Y
Power
Dissipation
.
'l
Watt
"NOTICE: Stresses above fhose Iisted under
"Absolute
Maximum Rafings"
may cause
permanent damage to
the
device.Thisis
a
stress
rating
only and
f
unctional operation
of
the device at these or any
other conditions above those
indicated in
the operational secfions of
thls
specif
ication
is not implied.
Exposure ta
absolute maximum rating
con-
ditions
for
extended
periods
may
affect device
reliability.
D.C. CHARACTERISTICS
On
:
0"C
to
70"C,
V66
:
5.0V
r10%,
GND
-
0V).
CAPACITANCE
(TR
-
zs"c,Vcc
- cND r
ov)
Pa
ra
meter
;----]
=
- -l
r
--l
:--l
I
-:-]
Max.
Unit Test
Conditions
fc
,-
l
MHz
10
ctru
Inp
ut
Capac itan ce
ct/o
I
O Capacitance
20
A.C. CHARACTERISTICS (rn
:
0"C
to
70"C,
V66 = 5.0v r10%,
GND
-
0V)
Bus Parameters
(Note
1)
READ
CYCLE
Symbol
Pa ra
meter
Min.
Address Stable Before
READ (CS,
C D)
Address Hold Time
for
nfnO
(CS,
C,,D)
READ Pulse Width
Data Delay
f
rom
READ
READ
to
Data
Floating
pF
Unmeasured pins returned
to
GND
Note
Note
Unit
Param
Input
Low Voltage
Input
High Voltage
Output
Low Voltage
Output
High Voltage
Output Float
Leakage
I
nput
Leakage
Power
Supply
Curren
eter
Min. Max. Unit Test Conditions
05
OB V
20
Vcc
V
0.45
V
lOl
- 2.2
mA
24
V IOL
-
400 pA
i-
10
pA
VOU1
-
VCC
TO 0.45V
r.1 0
pA
Vlru
-'
VCC TO 0.45V
t
100
mA
All Outputs
-=
High
Symbol
Conditions
tB4
tRF
tRo
WRITE
CYCLE
Symbol Parameter Min. Max. Unit Test Condtions
tRw
Address Stable
Before
VVRITE 0
NS
twR Address Hold Time for
WRITE
0 NS
tww
WRITE Pulse Width 250
NS
tow
Data Set-Up
Time
tor
WRttf
150
NS
two
Data
Ho
ld
Time
f
or
WR
ITE 20
NS
tRv Recovery
Time
Between WRITES
6
tcv
Note
4
6-133
AFN.O1573D