Digilent 410-308P - Manual (Page 12)

JTAG-SMT2-NC Reference Manual
Copyright Digilent, Inc. All rights reserved.
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Page 12 of 14
General USB Signal Routing Guidelines

Maintain a differential impedance of 90 ohms between the DP and DM signals.

Keep DP and DM trace lengths within 50 mils of each other.

Minimize DP and DM signal trace length. Keeping the trace length below 3 inches is recommended.

When possible, route DP and DM on the plane closest to the ground plane.

When possible, avoid routing the DP and DM signals through vias. If vias cannot be avoided, then keep
them small and place the DP and DM traces on the same layer.

When possible, avoid routing other traces near DP and DM.

When possible, minimize or avoid the use of bends in the DP and DM traces. If 90 degree bends are
necessary, then use two 45 degree turns or an arc instead of a single 90 degree turn.

Do NOT route DP or DM near oscillators, crystals, switching regulators, clock generators, or inductors.
Absolute Maximum Ratings
Symbol Parameter Condition Min Max Unit
Vdd Operating supply voltage -0.3 4.0 V
Vref I/O reference/supply voltage -0.3 6 V
VIO Signal Voltage -0.3 6 V
I
IK
,I
OK
TMS, TCK, TDI, TDO, GPIO0, GPIO1,
GPIO2
DC Input/Output Diode Current
VIO < -0.3V -50
mA
VIO > 6V +20
I
OUT
DC Output Current ±50 mA
T
STG
Storage Temperature -20 +120 ºC
ESD
Human Body Model JESD22-A114 4000 V
Charge Device Model JESD22-C101 2000 V
DC Operating Characteristics
Symbol Parameter Min Typ Max Unit
Vdd Operating supply voltage 2.97 3.3 3.63 Volts
Vref I/O reference/supply voltage 1.65 2.5/3.3 5.5 Volts
TDO, GPIO0,
GPIO1, GPIO2
Input High Voltage (V
IH
) 1.62 5.5 Volts
Input Low Voltage (V
IL
) 0 0.65 Volts
TMS, TCK, TDI,
GPIO0, GPIO1,
GPIO2 Output High (V
OH
) 0.85 x Vref 0.95 x Vref Vref Volts
Output Low (V
OL
) 0 0.05 x Vref 0.15 x Vref Volts
T
A
Operating Temperature 0 70 ºC