8525BGLFT IDT, 8525BGLFT Datasheet - Page 8

• Manufacturer Part Number: 8525BGLFT
• Description: Clock Drivers & Distribution
• Manufacturer: IDT

Specifications of 8525BGLFT

• Rohs: yes
• Part # Aliases: ICS8525BGLFT

This section provides information on power dissipation and junction temperature for the ICS8525.
Equations and example calculations are also provided.
1. Power Dissipation.
The total power dissipation for the ICS8525 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.
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
In order to calculate junction temperature, the appropriate junction-to-ambient thermal resistance
moderate air low of 200 linear feet per minute and a multi-layer board, the appropriate value is 66.6°C/W per Table 6 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 (single layer or multi-layer).
T
8525BG
ABLE
Single-Layer PCB, JEDEC Standard Test Boards
Multi-Layer PCB, JEDEC Standard Test Boards
NOTE: Most modern PCB designs use multi-layered boards. The data in the second row pertains to most designs.
6. T
Power (core)
Power (outputs)
If all outputs are loaded, the total power is 4 x 32.8mW = 131.2mW
Total Power
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
70°C + 0.305W * 66.6°C/W = 90.3°C. This is well below the limit of 125°C.
JA
A
= Ambient Temperature
HERMAL
= junction-to-ambient thermal resistance
R
MAX
ESISTANCE
_MAX
MAX
= V
(3.465V, with all outputs switching) = 173.25mW + 131.2mW = 304.45mW
= 32.8mW/Loaded Output pair
DD_MAX
JA
* I
FOR
DD_MAX
20-
JA
P
DD
= 3.465V * 50mA = 173.25mW
www.icst.com/products/hiperclocks.html
by Velocity (Linear Feet per Minute)
= 3.3V + 5% = 3.465V, which gives worst case results.
PIN
OWER
JA
TSSOP, F
* Pd_total + T
C
ONSIDERATIONS
ORCED
8
A
114.5°C/W
C
73.2°C/W
ONVECTION
0
LVCMOS-
TM
devices is 125°C.
98.0°C/W
66.6°C/W
TO
200
-LVHSTL F
JA
L
must be used. Assuming a
OW
88.0°C/W
63.5°C/W
500
ANOUT
S
ICS8525
KEW
REV. C AUGUST 1, 2007
, 1-
B
UFFER
TO
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