ICS8530I-01 View Datasheet(PDF) - Integrated Circuit Systems
Part Name
Description
MFG CO.
'ICS8530I-01' PDF : 17 Pages View PDF
Integrated
Circuit
Systems, Inc.
PRELIMINARY
ICS8530I-01
LOW SKEW, 1-TO-16
DIFFERENTIAL-TO-3.3V LVPECL FANOUT BUFFER
POWER CONSIDERATIONS
This section provides information on power dissipation and junction temperature for the ICS8530I-01.
Equations and example calculations are also provided.
1. Power Dissipation.
The total power dissipation for the ICS8530I-01 is the sum of the core power plus the power dissipated in the load(s).
The following is the power dissipation for VCC = 3.3V + 5% = 3.465V, which gives worst case results.
NOTE: Please refer to Section 3 for details on calculating power dissipated in the load.
• Power (core)MAX = VCC_MAX * IEE_MAX = 3.465V * 115mA = 398.5mW
• Power (outputs) = 30mW/Loaded Output pair
MAX
If all outputs are loaded, the total power is 16 * 30mW = 480mW
Total Power_MAX (3.465V, with all outputs switching) = 398.5mW + 480mW = 878.5mW
2. Junction Temperature.
Junction temperature, Tj, is the temperature at the junction of the bond wire and bond pad and directly affects the reliability of the
device. The maximum recommended junction temperature for HiPerClockSTM devices is 125°C.
The equation for Tj is as follows: Tj = θJA * Pd_total + TA
Tj = Junction Temperature
θJA = Junction-to-Ambient Thermal Resistance
Pd_total = Total Device Power Dissipation (example calculation is in section 1 above)
TA = Ambient Temperature
In order to calculate junction temperature, the appropriate junction-to-ambient thermal resistance θJA must be used. Assuming a
moderate air flow of 200 linear feet per minute and a multi-layer board, the appropriate value is 22.6°C/W per Table 6 below.
Therefore, Tj for an ambient temperature of 85°C with all outputs switching is:
85°C + 0.879W * 22.6°C/W = 104.9°C. This is well below the limit of 125°C.
This calculation is only an example. Tj will obviously vary depending on the number of loaded outputs, supply voltage, air flow,
and the type of board (single layer or multi-layer).
TABLE 6. THERMAL RESISTANCE θJA FOR 48-PIN TQFP, E-PAD FORCED CONVECTION
θJA by Velocity (Linear Feet per Minute)
Multi-Layer PCB, JEDEC Standard Test Boards
0
27.6°C/W
200
22.6°C/W
500
20.7°C/W
8530DYI-01
www.icst.com/products/hiperclocks.html
13
REV. A FEBRUARY 25, 2005
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