Datasheet

JTAG-SMT2-NC™ Programming Module for Xilinx® FPGAs
Copyright Digilent, Inc. All rights reserved.
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Page 12 of 13
8 AC Operating Characteristics
The JTAG-SMT2-NC’s JTAG signals operate according to the timing diagram in Fig. 12. The SMT2-NC supports
JTAG/TCK frequencies from 30 MHz to 8 KHz at integer divisions of 30 MHz from 1 to 3750. Common frequencies
include 30 MHz, 15 MHz, 10 Mhz, 7.5 MHz, and 6 MHz (see Table 2). The JTAG/TCK operating frequency can be set
within the Xilinx tools.
Note: Please refer to Xilinx’s iMPACT documentation for more information.
TDI
TCK
TDO
T
CKH
T
CKL
T
CK
T
CD_TDI
T
HD
T
SETUP
TMS
T
CD_TMS
9 Mounting to Host PCBs
The JTAG-SMT2-NC module has a moisture sensitivity level (MSL) of 6. Prior to reflow, the JTAG-SMT2-NC module
must be dried by baking it at 125° C for 17 hours. Once this process has been completed, the module has a MSL of
3 and is suitable for reflow for up to 168 hours without additional drying.
The factory finishes the JTAG-SMT2-NC signal pads with the ENIG process using 2u” gold over 150u” electroless
nickel. This makes the SMT2-NC compatible with most mounting and reflow processes (see Fig. 13). The binding
force of the solder is sufficient to hold the SMT2-NC firmly in place so mounting should require no additional
adhesives.
Symbol
Parameter
Min
Max
T
CK
T
CK
period
30ns
125µs
T
CKH
, T
CKL
T
CLK
pulse width
15ns
62.5µs
T
CD_TMS
T
CLK
to TMS
-0.5ns
12.35ns
T
CD_TDI
T
CLK
to TDI
-0.5ns
8.15ns
T
SETUP
TDO Setup time
15.8ns
T
HD
TDO Hold time
0ns
Figure 12. Timing diagram.
Table 2. JTAG frequency support.
Note: these parameters are specified for Vref = 3.3V.