adsp-2165ks-80 Analog Devices, Inc., adsp-2165ks-80 Datasheet - Page 16

• Manufacturer Part Number: adsp-2165ks-80
• Description: Dsp Microcomputers With Rom
• Manufacturer: Analog Devices, Inc.

ADSP-216x
SPECIFICATIONS
ADSP-2161/ADSP-2163/ADSP-2165
TEST CONDITIONS
Figure 12 shows voltage reference levels for ac measurements.
Figure 12. Voltage Reference Levels for AC Measurements
(Except Output Enable/Disable)
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 Figure 13. The time t
when a reference signal reaches a high or low voltage level to
when the output voltages have changed by 0.5 V from the mea-
sured output high or low voltage.
The decay time, t
C
proximated 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.
L
, and the current load, i
OUTPUT
INPUT
DIS
) is the difference of t
DECAY
t
DIS
t
, is dependent on the capacitative load,
DECAY
= t
L
MEASURED
, on the output pin. It can be ap-
MEASURED
C
L
i
0 5 .
L
– t
MEASURED
DECAY
V
is the interval from
3.0V
1.5V
0.0V
2.0V
1.5V
0.8V
and t
DECAY
, as
–16–
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 Figure 13. If multiple pins (such as the data bus) are enabled,
the measurement value is that of the first pin to start driving.
REFERENCE
OUTPUT
(MEASURED)
(MEASURED)
SIGNAL
Measurements (Except Output Enable/Disable)
Figure 14. Equivalent Device Loading for AC
V
V
OUTPUT
OL
OH
Figure 13. Output Enable/Disable
OUTPUT STOPS
PIN
t
TO
t
MEASURED
DIS
DRIVING
50pF
HIGH-IMPEDANCE STATE. TEST CONDITIONS CAUSE
V
V
THIS VOLTAGE LEVEL TO BE APPROXIMATELY 1.5V.
OH
OL
t
DECAY
(MEASURED) +0.5V
(MEASURED) – 0.5V
ENA
I
I
OH
OL
) is the interval from when
OUTPUT STARTS
1.0V
2.0V
DRIVING
t
ENA
+1.5V
V
(MEASURED)
V
(MEASURED)
OH
OL
REV. 0