8T49N286 Datasheet, PDF (72/78 Pages) Integrated Circuit Systems – Bypass clock paths for system tests

8T49N286 DATA SHEET
Example 3. Low Power Customer Configuration (2.5V Core Voltage)
Output
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7
PLL0
PLL1
Output Type
LVDS
LVDS
LVDS
LVCMOS
LVCMOS
LVCMOS
LVCMOS
LVDS
Frequency (MHz)
156.25
156.25
161.133
33.333
25
25
25
156.25
Enabled
Enabled
V_CCO
2.5
2.5
2.5
1.8
1.8
1.8
1.8
2.5
• Core Supply Current, I_CC = 95mA (max)
• Analog Supply Current, I_CCA = 270mA (max)
Q0 Current = 0.00366x156.25 + 40.8 = 41.37mA
Q1 Current = 0.00366x156.25 + 40.8 = 41.37mA
Q2 Current = 0.01148x161.133 + 64.5 = 66.35mA
Q3 Current = 51.4mA
Q4 Current = 30.3mA
Q5 Current = 30.3mA
Q6 Current = 30.3mA
Q7 Current = 0.00367x156.25 + 43.7 = 44.27mA
• Total Output Current = 193.36mA (V_CCO = 2.5V), 142.3mA (V_CCO = 1.8V)
Total Device Power = 2.625V *(95mA + 270mA + 193.36mA) + 1.89V * 142.3mA = 1734.6mW
• Power dissipated through output loading:
LVPECL = n/a
LVDS = already accounted for in device power
HCSL = n/a
LVCMOS_33.3MHz = 17pF * 33.3MHz * 1.89V² * 1 output pair = 2.02mW
LVCMOS_25MHz = 12.5pF * 25MHz * 1.89V² * 3 output pairs = 3.35mW
Total Power = 1734.6mW + 2.02mW + 3.35mW = 1740mW or 1.74W
With an ambient temperature of 85°C, the junction temperature is:
T_J = 85°C + 16.1°C/W *1.74W = 113°C
This junction temperature is below the maximum allowable.
FEMTOCLOCK^® NG OCTAL UNIVERSAL FREQUENCY TRANSLATOR
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REVISION 5 07/08/15