8T49N281 Datasheet, PDF (53/63 Pages) Integrated Device Technology – Operating modes: locked to input signal

8T49N281 DATA SHEET
Thermal Considerations
Once the total power consumption has been determined, it is necessary to calculate the maximum operating junction temperature for the device
under the environmental conditions it will operate in. Thermal conduction paths, air flow rate and ambient air temperature are factors that can
affect this. The thermal conduction path refers to whether heat is to be conducted away via a heatsink, via airflow or via conduction into the
PCB through the device pads (including the ePAD). Thermal conduction data is provided for typical scenarios in Table 14 below. Please contact
IDT for assistance in calculating results under other scenarios.
Table 14. Thermal Resistance _JA for 56-Lead VFQFN, Forced Convection
_JA by Velocity
Meters per Second
0
Multi-Layer PCB, JEDEC Standard Test Boards
16.0°C/W
1
12.14°C/W
2
11.02°C/W
Current Consumption Data and Equations
Table 15A. 3.3V LVPECL Output Calculation Table
LVPECL
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7
FQ_Factor (mA/MHz)
0.00624
0.01445
0.00609
Base_Current (mA)
40.3
63.6
42.2
Table 15D. 2.5V LVDS Output Calculation Table
LVDS
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7
FQ_Factor (mA/MHz)
0.00412
0.01217
Base_Current (mA)
41.9
65.3
0.00425
43.6
Table 15B. 2.5V LVPECL Output Calculation Table
LVPECL
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7
FQ_Factor (mA/MHz)
0.00409
0.01179
0.00369
Base_Current (mA)
33.0
56.4
35.4
Table 15E. 3.3V LVCMOS Output Calculation Table
LVCMOS
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7
Base_Current (mA)
37.5
61.1
40.1
Table 15C. 3.3V LVDS Output Calculation Table
LVDS
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7
FQ_Factor (mA/MHz)
0.00664
0.01479
Base_Current (mA)
49.6
73.0
0.00646
51.5
Table 15F. 2.5V LVCMOS Output Calculation Table
LVCMOS
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7
Base_Current (mA)
31.0
54.6
33.2
REVISION 4 07/08/15
53
FEMTOCLOCK^® NG OCTAL UNIVERSAL FREQUENCY TRANSLATOR