831721AGILF IDT, 831721AGILF Datasheet - Page 13

• Manufacturer Part Number: 831721AGILF
• Description: Clock Drivers & Distribution
• Manufacturer: IDT

Specifications of 831721AGILF

• Product Category: Clock Drivers & Distribution
• Rohs: yes
• Part # Aliases: ICS831721AGILF

ICS831721I Data Sheet
Power Considerations
This section provides information on power dissipation and junction temperature for the ICS831752I.
Equations and example calculations are also provided.
1.
The total power dissipation for the ICS831752I is the sum of the core power plus the analog 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
a multi-layer board, the appropriate value is 100.3°C/W per Table 6 below.
Therefore, Tj for an ambient temperature of 85°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 6. Thermal Resistance
ICS831721AGI REVISION A AUGUST 19, 2011
Meters per Second
Multi-Layer PCB, JEDEC Standard Test Boards
Power Dissipation.
•
•
85°C + 0.140W * 100.3°C/W = 99°C. This is below the limit of 125°C.
Power (core)
Power (outputs)
The equation for Tj is as follows: Tj =
Tj = Junction Temperature
Pd_total = Total Device Power Dissipation (example calculation is in section 1 above)
T
A
JA
= Ambient Temperature
= Junction-to-Ambient Thermal Resistance
MAX
(3.63V, with all outputs switching) = 93.6mW + 46.8mW = 140.4mW
MAX
MAX
= V
= 46.8mW/Loaded Output Pair
DD_MAX
JA
* I
for 16 Lead TSSOP, Forced Convection
DD_MAX
DD
= 3.3V + 0.3V = 3.6V, which gives worst case results.
JA
= 3.6V * 26mA = 93.6mW
* Pd_total + T
A
JA
100.3°C/W
by Velocity
13
0
96.0°C/W
JA
1
must be used. Assuming no air flow and
DIFFERENTIAL CLOCK/DATA MULTIPLEXER
©2011 Integrated Device Technology, Inc.
93.9°C/W
2.5