ics8430ay62l Integrated Device Technology, ics8430ay62l Datasheet - Page 17

• Manufacturer Part Number: ics8430ay62l
• Description: Ics8430-62 500mhz, Crystal-to-3.3v, 2.5v Differential Lvpecl Frequency Synthesizer
• Manufacturer: Integrated Device Technology

ICS8430-62 Datasheet
Power Considerations
This section provides information on power dissipation and junction temperature for the ICS8430-62.
Equations and example calculations are also provided.
1.
The total power dissipation for the ICS8430-62 is the sum of the core power plus the power dissipated in the load(s).
The following is the power dissipation for V
NOTE: Please refer to Section 3 for details on calculating power dissipated in the load.
Total Power_
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 HiPerClockS devices is 125°C.
In order to calculate junction temperature, the appropriate junction-to-ambient thermal resistance θ
a multi-layer board, the appropriate value is 65.7°C/W per Table 8 below.
Therefore, Tj for an ambient temperature of 70°C with all outputs switching is:
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 (multi-layer).
Table 8. Thermal Resistance
ICS8430AY-62 REVISION A JULY 2, 2009
Meters per Second
Multi-Layer PCB, JEDEC Standard Test Boards
Power Dissipation.
•
•
Power (core)
Power (outputs)
If all outputs are loaded, the total power is 2 * 30mW = 60mW
The equation for Tj is as follows: Tj = θ
Tj = Junction Temperature
θ
Pd_total = Total Device Power Dissipation (example calculation is in section 1 above)
T
70°C + 0.510W * 65.7°C/W = 103.5°C. This is well below the limit of 125°C.
JA
A
= Ambient Temperature
= Junction-to-Ambient Thermal Resistance
MAX
(3.3V, with all outputs switching) = 450.45mW + 60mW = 510.45mW
MAX
MAX
= V
= 30mW/Loaded Output pair
CC_MAX
θ
JA
* I
for 32 Lead LQFP, Forced Convection
EE_MAX
CC
= 3.3V + 5% = 3.465V, which gives worst case results.
JA
= 3.465V * 130mA = 450.45mW
* Pd_total + T
θ
JA
65.7°C/W
A
by Velocity
0
17
500MHz CRYSTAL-TO-3.3V, 2.5V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER
55.9°C/W
1
JA
must be used. Assuming no air flow and
©2009 Integrated Device Technology, Inc.
52.4°C/W
2.5