ADSP-BF525_15 Datasheet, PDF (75/88 Pages) Analog Devices – Blackfin Embedded Processor

ADSP-BF522/ADSP-BF523/ADSP-BF524/ADSP-BF525/ADSP-BF526/ADSP-BF527
60
50
40
30
20
10
0
–10
–20
–30
–40
–50
–60
0
0.5
1.0
V_DDEXT = 3.6V @ – 40°C
V_DDEXT = 3.3V @ 25°C
V = 3.0V @ 105°C
DDEXT
V_OL
1.5
2.0
2.5
3.0
3.5
SOURCE VOLTAGE (V)
Figure 55. Driver Type E Current (3.3V V_DDEXT/V_DDMEM)
40
V_DDEXT = 2.75V @ – 40°C
30
V_DDEXT = 2.5V @ 25°C
V_DDEXT = 2.25V @ 105°C
20
10
0
–10
V_OL
–20
–30
–40
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
SOURCE VOLTAGE (V)
Figure 56. Driver Type E Current (2.5V V_DDEXT/V_DDMEM)
20
V_DDEXT = 1.9V @ – 40°C
15
V = 1.8V @ 25°C
DDEXT
V = 1.7V @ 105°C
DDEXT
10
5
0
–5
V_OL
–10
–15
–20
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
SOURCE VOLTAGE (V)
Figure 57. Driver Type E Current (1.8V V_DDEXT/V_DDMEM)
TEST CONDITIONS
All Timing Requirements appearing in this data sheet were
measured under the conditions described in this section.
Figure 58 shows the measurement point for AC measurements
(except output enable/disable). The measurement point V_MEAS is
V_DDEXT/2 or V_DDMEM/2 for V_DDEXT/V_DDMEM (nominal) = 1.8 V/
2.5 V/3.3 V.
INPUT
OR
OUTPUT
V_MEAS
V_MEAS
Figure 58. Voltage Reference Levels for AC Measurements
(Except Output Enable/Disable)
Output Enable Time Measurement
Output balls 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 59.
t_DIS
V_OH
(MEASURED)
V_OL
(MEASURED)
REFERENCE
SIGNAL
t_{DIS_MEASURED}
t_ENA
V_OH (MEASURED) ؊ ⌬V
V_OL (MEASURED) + ⌬V
t_DECAY
t_{ENA_MEASURED}
V_OH(MEASURED)
V_TRIP(HIGH)
V_TRIP(LOW)
V_OL(MEASURED)
t_TRIP
OUTPUT STOPS DRIVING
OUTPUT STARTS DRIVING
HIGH IMPEDANCE STATE
Figure 59. Output Enable/Disable
The time t_{ENA_MEASURED} is the interval from when the reference
signal switches to when the output voltage reaches V_TRIP(high)
or V_TRIP(low). For V_DDEXT/V_DDMEM (nominal) = 1.8 V, V_TRIP
(high) is 1.05 V, and V_TRIP (low) is 0.75 V. For V_DDEXT/V_DDMEM
(nominal) = 2.5 V, V_TRIP (high) is 1.5 V and V_TRIP (low) is 1.0 V.
For V_DDEXT/V_DDMEM (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 out-
put 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:
t_ENA = t_{ENA_MEASURED} – t_TRIP
If multiple balls (such as the data bus) are enabled, the measure-
ment value is that of the first ball to start driving.
Rev. D | Page 75 of 88 | July 2013