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ADSP-21365/6
Preliminary Technical Data
Rev. PrA
|
Page 43 of 54
|
September 2004
OUTPUT DRIVE CURRENTS
Figure 36
shows typical I-V characteristics for the output driv-
ers of the ADSP-21365/6. 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 20
through
Table 38 on page 42
. 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 37
.
Timing is measured on signals when they cross the 1.5 V level as
described in
Figure 38
. All delays (in nanoseconds) are mea-
sured 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 37
).
Figure 41
shows graphically
how output delays and holds vary with load capacitance. The
graphs of
Figure 39
,
Figure 40
, and
Figure 41
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 36. ADSP-21365/6 Typical Drive
Figure 37. Equivalent Device Loading for AC Measurements
(Includes All Fixtures)
Figure 38. 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 39. Typical Output Rise/Fall Time (20%-80%,
V
DDEXT
= Max)
Figure 40. 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