adsp-2186n Analog Devices, Inc., adsp-2186n Datasheet - Page 25

• Manufacturer Part Number: adsp-2186n
• Description: Dsp Microcomputer
• Manufacturer: Analog Devices, Inc.

ENVIRONMENTAL CONDITIONS
Table 14. Thermal Resistance
1
TEST CONDITIONS
Figure 19. Equivalent Loading for AC Measurements (Including All Fixtures)
Rating Description
Thermal Resistance (Case-
to-Ambient)
Thermal Resistance
(Junction-to-Ambient)
Thermal Resistance
(Junction-to-Case)
Where the Ambient Temperature Rating (T
Figure 18. Voltage Reference Levels for AC Measurements (Except Output
T
T
PD = Power Dissipation in W
AMB
CASE
= T
= Case Temperature in °C
CASE
OUTPUT
OUTPUT
INPUT
– (PD × θ
PIN
TO
CA
50pF
1
)
Enable/Disable)
Symbol
θ
θ
θ
CA
JA
JC
I
I
OL
OH
AMB
) is:
LQFP
(°C/W)
48
50
2
0.8V
1.5V
1.5V
2.0V
1.5V
Rev. A | Page 25 of 48 | August 2006
BGA
(°C/W)
63.3
70.7
7.4
Output Disable Time
Output pins are considered to be disabled when they have
stopped driving and started a transition from the measured out-
put high or low voltage to a high impedance state. The output
disable time (t
shown in
ence signal reaches a high or low voltage level to when the
output voltages have changed by 0.5 V from the measured out-
put high or low voltage.
The decay time, t
and the current load, i
mated by the following equation:
from which
is calculated. If multiple pins (such as the data bus) are disabled,
the measurement value is that of the last pin to stop driving.
Output Enable Time
Output pins are considered to be enabled when they have made
a transition from a high-impedance state to when they start
driving. The output enable time (t
a reference signal reaches a high or low voltage level to when the
output has reached a specified high or low trip point, as shown
in
the measurement value is that of the first pin to start driving.
REFERENCE
Figure
OUTPUT
(MEASURED)
(MEASURED)
SIGNAL
20. If multiple pins (such as the data bus) are enabled,
Figure
V
V
OH
OL
DIS
OUTPUT STOPS
) is the difference of t
20. The time is the interval from when a refer-
t
t
DECAY
t
Figure 20. Output Enable/Disable
DIS
DIS
MEASURED
DRIVING
t
HIGH-IMPEDANCE STATE. TEST CONDITIONS CAUSE
THIS VOLTAGE LEVEL TO BE APPROXIMATELY 1.5V.
DECAY
, is dependent on the capacitive load, C
L
=
, on the output pin. It can be approxi-
V
V
t
OH
MEASURED
OL
t
DECAY
(MEASURED) – 0.5V
(MEASURED) + 0.5V
=
C
----------------------- -
L
ENA
×
i
L
–
0.5V
) is the interval from when
MEASURED
t
DECAY
ADSP-218xN
OUTPUT STARTS
1.0V
2.0V
and t
DRIVING
t
ENA
DECAY
V
(MEASURED)
V
(MEASURED)
OH
OL
, as
L
,