851010AYLF IDT, 851010AYLF Datasheet - Page 10

• Manufacturer Part Number: 851010AYLF
• Description: Clock Drivers & Distribution
• Manufacturer: IDT

Specifications of 851010AYLF

• Product Category: Clock Drivers & Distribution
• Rohs: yes
• Part # Aliases: ICS851010AYLF

ICS851010 Data Sheet
Power Considerations
This section provides information on power dissipation and junction temperature for the ICS851010.
Equations and example calculations are also provided.
1.
The total power dissipation for the ICS851010 is the sum of the core power plus the power dissipated in the load(s). The following is the power
dissipation for V
Total Power_
2. Junction Temperature.
Junction temperature, Tj, is the temperature at the junction of the bond wire and bond pad directly affects the reliability of the device. The
maximum recommended junction temperature is 125°C. Limiting the internal transistor junction temperature, Tj, to 125°C ensures that the bond
wire and bond pad temperature remains below 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 4 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 4. Thermal Resistance
ICS851010AY REVISION A AUGUST 2, 2010
Meters per Second
Multi-Layer PCB, JEDEC Standard Test Boards
Power Dissipation.
•
•
•
70°C + 0.809W * 65.7°C/W = 123.2°C. This is below the limit of 125°C.
Power (core)
Power (outputs)
If all outputs are loaded, the total power is 10 * 44.5mW = 445mW
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
JA
A
= Ambient Temperature
= Junction-to-Ambient Thermal Resistance
MAX
DD
(3.465V, with all outputs switching) = 363.825mW + 445mW = 808.825mW
= 3.3V + 5% = 3.465V, which gives worst case results.
MAX
MAX
= V
= 44.5mW/Loaded Output Pair
DD_MAX
θ
JA
* I
for 32 Lead LQFP, Forced Convection
DD_MAX
JA
= 3.465V * 105mA = 363.825mW
* Pd_total + T
θ
A
JA
65.7°C/W
by Velocity
10
0
55.9°C/W
JA
1
must be used. Assuming no air flow and
1-to-10, DIFFERENTIAL HCSL FANOUT BUFFER
©2010 Integrated Device Technology, Inc.
52.4°C/W
2.5