Datasheet

Rev. A | Page 50 of 80 | July 2011
ADSP-BF504/ADSP-BF504F/ADSP-BF506F
PROCESSOR—TEST CONDITIONS
All timing parameters appearing in this data sheet were mea-
sured under the conditions described in this section. Figure 41
shows the measurement point for AC measurements (except
output enable/disable). The measurement point V
MEAS
is V
DDEXT
/2
for V
DDEXT
(nominal) = 1.8 V/2.5 V/3.3 V.
Output Enable Time Measurement
Output pins are considered to be enabled when they have made
a transition from a high impedance state to the point when they
start driving.
The output enable time t
ENA
is the interval from the point when a
reference signal reaches a high or low voltage level to the point
when the output starts driving as shown on the right side of
Figure 42.
The time t
ENA _ MEASURED
is the interval, from when the reference sig-
nal switches, to when the output voltage reaches V
TRIP
(high) or
V
TRIP
(low). For V
DDEXT
(nominal) = 1.8 V, V
TRIP
(high) is 1.05 V,
and V
TRIP
(low) is 0.75 V. For V
DDEXT
(nominal) = 2.5 V, V
TRIP
(high) is 1.5 V and V
TRIP
(low) is 1.0 V. For V
DDEXT
(nominal) =
3.3 V, V
TRIP
(high) is 1.9 V, and V
TRIP
(low) is 1.4 V. Time t
TRIP
is
the interval from when the output starts driving to when the
output reaches the V
TRIP
(high) or V
TRIP
(low) trip voltage.
Time t
ENA
is calculated as shown in the equation:
If multiple pins are enabled, the measurement value is that of
the first pin to start driving.
Figure 38. Driver Type D Current (3.3 V V
DDEXT
)
Figure 39. Driver Type D Current (2.5 V V
DDEXT
)
Figure 40. Driver Type D Current (1.8 V V
DDEXT
)
0
SOURCE CURRENT (mA)
SOURCE VOLTAGE (V)
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
–40
–10
V
OL
V
DDEXT
= 3.6V @ – 55 ° C
V
DDEXT
= 3.3V @ 25 ° C
–20
–30
V
DDEXT
= 3.0V @ 125 ° C
–50
–60
0
SOURCE CURRENT (mA)
SOURCE VOLTAGE (V)
0 0.5 1.0 1.5 2.0 2.5
–35
–25
–10
V
OL
V
DDEXT
= 2.75V @ – 55 ° C
V
DDEXT
= 2.5V @ 25 ° C
–15
V
DDEXT
= 2.25V @ 125 ° C
–20
–5
–30
SOURCE CURRENT (mA)
SOURCE VOLTAGE (V)
0 0.5 1.0 1.5 2
0
–16
–12
V
OL
V
DDEXT
= 1.9V @ – 55 ° C
V
DDEXT
= 1.8V @ 25 ° C
–14
V
DDEXT
= 1.7V @ 125 ° C
–2
–4
–8
–6
–10
Figure 41. Voltage Reference Levels for AC
Measurements (Except Output Enable/Disable)
Figure 42. Output Enable/Disable
INPUT
OR
OUTPUT
V
MEAS
V
MEAS
REFERENCE
SIGNAL
t
DIS
OUTPUT STARTS DRIVING
V
OH
(MEASURED) ⴚ ⌬V
V
OL
(MEASURED) + ⌬V
t
DIS_MEASURED
V
OH
(MEASURED)
V
OL
(MEASURED)
V
TRIP
(HIGH)
V
OH
(MEASURED
)
V
OL
(MEASURED)
HIGH IMPEDANCE STATE
OUTPUT STOPS DRIVING
t
ENA
t
DECAY
t
ENA_MEASURED
t
TRIP
V
TRIP
(LOW)
t
ENA
t
ENA_MEASURED
t
TRIP
–=