ACS8520T Semtech, ACS8520T Datasheet - Page 133

• Manufacturer Part Number: ACS8520T
• Description: Synchronous Equipment Timing Source (SETS) for Stratum 3/4E/4 and SMC Systems
• Manufacturer: Semtech

JTAG
The JTAG connections on the ACS8520 allow a full
boundary scan to be made. The JTAG implementation is
fully compliant to IEEE 1149.1
exceptions, and the user should refer to the standard for
further information.
1. The output boundary scan cells do not capture data
2. In common with some other manufacturers, pin TRST
The JTAG timing diagram is shown in Figure 22.
Over-voltage Protection
The ACS8520 may require Over-Voltage Protection on
input reference clock ports according to ITU
Figure 22 JTAG Timing
Table 31 JTAG Timing (for use with Figure 22)
Revision 3.02/October 2005 © Semtech Corp.
Electrical Specifications
ADVANCED COMMUNICATIONS
Cycle Time
TMS/TDI to TCK rising edge time
TCK rising to TMS/TDI hold time
TCK falling to TDO valid
from the core, and so do not support INTEST. However
this does not affect board testing.
is internally pulled Low to disable JTAG by default. The
standard is to pull High. The polarity of TRST is as the
standard: TRST High to enable JTAG boundary scan
mode, TRST Low for normal operation.
Parameter
TCK
TMS
TDO
TDI
[5]
, with the following minor
t
SUR
Symbol
t
t
t
t
DOD
CYC
SUR
HT
t
HT
FINAL
Page 133
Minimum
50
23
3
recommendation K.41
are recommended for this purpose (see separate
Semtech data book).
ESD Protection
Suitable precautions should be taken to protect against
electrostatic damage during handling and assembly. This
device incorporates ESD protection structures that
protect the device against ESD damage at ESD input
levels up to at least ±2 kV using the Human Body Model
(HBD) MIL-STD-883D Method 3015.7, for all pins except
pins 24, 25, 26 and 27 (AMI I/Os) which are protected up
to at least ±1 kV.
Latchup Protection
This device is protected against latchup for input current
pulses of magnitude up to at least ±100 mA to JEDEC
Standard No. 78 August 1997.
-
t
CYC
t
DOD
Typical
-
-
-
-
[16]
F8110D_022JTAGTiming_01
. Semtech protection devices
Maximum
ACS8520 SETS
5
-
-
-
DATASHEET
www.semtech.com
Units
ns
ns
ns
ns