
Rev. PrA
|
Page 36 of 44
|
September 2004
ADSP-21363
Preliminary Technical Data
OUTPUT DRIVE CURRENTS
Figure 28
shows typical I-V characteristics for the output driv-
ers of the ADSP-21363. The curves represent the current drive
capability of the output drivers as a function of output voltage.
TEST CONDITIONS
The ac signal specifications (timing parameters) appear
Table 12 on Page 19
through
Table 32 on Page 35
. These include
output disable time, output enable time, and capacitive loading.
The timing specifications for the SHARC apply for the voltage
reference levels in
Figure 29
.
Timing is measured on signals when they cross the 1.5 V level as
described in
Figure 30 on Page 36
. All delays (in nanoseconds)
are measured between the point that the first signal reaches
1.5 V and the point that the second signal reaches 1.5 V.
CAPACITIVE LOADING
Output delays and holds are based on standard capacitive loads:
30 pF on all pins (see
Figure 29
).
Figure 33
shows graphically
how output delays and holds vary with load capacitance. The
graphs of
Figure 31
,
Figure 32
, and
Figure 33
may not be linear
outside the ranges shown for Typical Output Delay vs. Load
Capacitance and Typical Output Rise Time (20%-80%, V=Min)
vs. Load Capacitance.
Figure 28. ADSP-21363 Typical Drive
Figure 29. Equivalent Device Loading for AC Measurements
(Includes All Fixtures)
Figure 30. Voltage Reference Levels for AC Measurements
SWEEP(VDDEXT) VOLTAGE (V)
-20
0
3.5
0.5
1
1.5
2
2.5
3
0
-40
-30
20
40
-10
S
VOL
3.11V, 125° C
3.3V, 25° C
3.47V, -45° C
VOH
30
10
3.11V, 125° C
3.3V, 25° C
3.47V, -45° C
1.5V
30pF
TO
OUTPUT
PIN
50
INPUT
OR
OUTPUT
1.5V
1.5V
Figure 31. Typical Output Rise/Fall Time (20%-80%,
V
DDEXT
= Max)
Figure 32. Typical Output Rise/Fall Time (20%-80%,
V
DDEXT
= Min)
LOAD CAPACITANCE (pF)
8
0
0
100
250
12
4
2
10
6
R
200
150
50
FALL
y = 0.0467x + 1.6323
y = 0.045x + 1.524
RISE
LOAD CAPACITANCE (pF)
12
0
50
100
150
200
250
10
8
6
4
R
2
0
RISE
FALL
y = 0.049x + 1.5105
y = 0.0482x + 1.4604