AD28msp01KST AD [Analog Devices], AD28msp01KST Datasheet - Page 21

• Manufacturer Part Number: AD28msp01KST
• Description: PSTN Signal Port
• Manufacturer: AD [Analog Devices]

REV. A
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 the Output Enable/Disable diagram. The time,
t
high or low voltage level to when the output voltages have
changed by 0.5 V from the measured output high or low volt-
age. The decay time, t
load, C
approximated by the following equation:
from which
is calculated. If multiple pins (such as the data bus) are dis-
abled, the measurement value is that of the last pin to stop
driving.
Serial Ports
Parameter
Timing Requirement:
t
t
Switching Characteristic:
t
t
t
t
MEASURED
SCS
SCH
RD
RH
SCDH
SCDD
L
, and the current load, i
, is the interval from when a reference signal reaches a
DIS
) is the difference of t
t
DIS
t
DECAY
DECAY
= t
MEASURED
, is dependent on the capacitive
SDOFS
SDIFS
SCLK
C
L
SDO
SDI
, on the output pin. It can be
L
i
– t
0.5 V
L
MEASURED
DECAY
SDI/SDIFS Setup before SCLK Low
SDI/SDIFS Hold after SCLK Low
SDOFS Delay from SCLK High
SDOFS Hold after SCLK High
SDO Hold after SCLK High
SDO Delay from SCLK High
t
SCS
and t
t
SCH
DECAY
t
Figure 19. Serial Ports
SCK
t
RD
, as
–21–
MSB
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 driv-
ing. The output enable time (t
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 the Output Enable/Disable diagram. If multiple pins (such as
the data bus) are enabled, the measurement value is that of the
first pin to start driving.
V
V
OH
OL
(MEASURED)
(MEASURED)
REFERENCE
t
SCDD
OUTPUT
t
RH
SIGNAL
t
SCS
2ND MSB
t
Figure 18. Output Enable/Disable
DECAY
t
SCH
t
OUTPUT STOPS
DIS
DRIVING
Min
10
15
0
0
t
MEASURED
3RD MSB
t
V
V
SCDH
OH
OL
(MEASURED)
(MEASURED)
HIGH-IMPEDANCE STATE. TEST CONDITIONS CAUSE THIS
VOLTAGE LEVEL TO BE APPROXIMATELY 1.5 V.
ENA
– 0.5V
+ 0.5V
) is the interval from when a
Max
30
30
AD28msp01
OUTPUT STARTS
2.0V
1.0V
DRIVING
t
ENA
V
V
OH
OL
(MEASURED)
(MEASURED)
Unit
ns
ns
ns
ns
ns
ns