ICS853S12AKILF IDT, Integrated Device Technology Inc, ICS853S12AKILF Datasheet - Page 12

• Manufacturer Part Number: ICS853S12AKILF
• Description: IC FANOUT BUFFER LVPECL 32-VFQFN
• Manufacturer: IDT, Integrated Device Technology Inc
• Series: HiPerClockS™r
• Type: Fanout Buffer (Distribution)r

Specifications of ICS853S12AKILF

• Number Of Circuits: 1
• Ratio - Input:output: 1:12
• Differential - Input:output: Yes/Yes
• Input: CML, LVPECL, SSTL
• Output: LVPECL
• Frequency - Max: 1.5GHz
• Voltage - Supply: 2.375 V ~ 3.465 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 32-VFQFN
• Frequency-max: 1.5GHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 800-1177; 853S12AKILF

This section provides information on power dissipation and junction temperature for the ICS853S12I.
Equations and example calculations are also provided.
1. Power Dissipation.
The total power dissipation for the ICS853S12I 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 θ
air flow and a multi-layer board, the appropriate value is 42.7°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 (single layer or multi-layer).
T
IDT
ABLE
ICS853S12I
LOW SKEW, 1-TO-12, DIFFERENTIAL-TO-3.3V, 2.5V LVPECL FANOUT BUFFER
™
•
•
/ ICS
6. T
Power (core)
Power (outputs)
If all outputs are loaded, the total power is 12 * 32mW = 384mW
Total Power
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
85°C + 0.859W * 42.7°C/W = 121.7°C. This is below the limit of 125°C.
™
JA
A
LVPECL FANOUT BUFFER
= Ambient Temperature
HERMAL
= Junction-to-Ambient Thermal Resistance
Multi-Layer PCB, JEDEC Standard Test Boards
R
MAX
ESISTANCE
_MAX
= V
MAX
(3.465V, with all outputs switching) = 474.7mW + 384mW = 858.7mW
= 32mW/Loaded Output pair
CC_MAX
θ θ θ θ θ
* I
JA
EE_MAX
FOR
= 3.465V * 137mA = 474.7mW
32 L
CC
θ θ θ θ θ
= 3.3V + 5% = 3.465V, which gives worst case results.
EAD
P
JA
OWER
JA
vs. Air Flow (Meter per Second)
VFQFN, F
* Pd_total + T
C
ORCED
ONSIDERATIONS
A
12
C
ONVECTION
42.7°C/W
TM
0
devices is 125°C.
37.3°C/W
1
ICS853S12AKI REV. A MAY 21, 2008
JA
must be used. Assuming no
33.5°C/W
2.5