ICS85311AMLF IDT, Integrated Device Technology Inc, ICS85311AMLF Datasheet - Page 11

• Manufacturer Part Number: ICS85311AMLF
• Description: IC FANOUT BUFF LVPECL/ECL 8-SOIC
• Manufacturer: IDT, Integrated Device Technology Inc
• Series: HiPerClockS™r
• Type: Fanout Buffer (Distribution)r

Specifications of ICS85311AMLF

• Number Of Circuits: 1
• Ratio - Input:output: 1:2
• Differential - Input:output: Yes/Yes
• Input: HCSL, LVDS, LVHSTL, LVPECL, SSTL
• Output: ECL, LVPECL
• Frequency - Max: 1GHz
• Voltage - Supply: 2.375 V ~ 3.465 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC
• Frequency-max: 1GHz
• Number Of Outputs: 4
• Operating Supply Voltage (max): -3.465/3.465V
• Operating Temp Range: 0C to 70C
• Propagation Delay Time: 1.4ns
• Operating Supply Voltage (min): -2.375/2.375V
• Mounting: Surface Mount
• Pin Count: 8
• Operating Supply Voltage (typ): -2.5/-3.3/2.5/3.3V
• Package Type: SOIC N
• Duty Cycle: 52%
• Operating Temperature Classification: Commercial
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 800-1166; 800-1166-5; 800-1166; 85311AMLF

Power Considerations
This section provides information on power dissipation and junction temperature for the ICS85311.
Equations and example calculations are also provided.
1.
The total power dissipation for the ICS85311 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
air flow of 200 linear feet per minute and a multi-layer board, the appropriate value is 103.3°C/W per Table 5 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).
Table 5. Thermal Resistance
NOTE: Most modern PCB designs use multi-layered boards. The data in the second row pertains to most designs.
IDT™ / ICS™ LVPECL/ECL FANOUT BUFFER
Linear Feet per Minute
Single-Layer PCB, JEDEC Standard Test Boards
Multi-Layer PCB, JEDEC Standard Test Boards
ICS85311
LOW SKEW, 1-TO-2, DIFFERENTIAL-TO-LVPECL/ECLFANOUT BUFFER
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 + 0.147W * 103.3°C/W = 85.2°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) = 86.6mW + 60mW = 146.6mW
MAX
MAX
= V
= 30mW/Loaded Output pair
CC_MAX
θ
JA
* I
for 24 Lead TSSOP, Forced Convection
EE_MAX
CC
= 3.3V + 5% = 3.465V, which gives worst case results.
JA
= 3.465V * 25mA = 86.6mW
* Pd_total + T
θ
153.3°C/W
112.7°C/W
JA
vs. Air Flow
A
0
11
128.5°C/W
103.3°C/W
200
JA
ICS85311AM REV. D OCTOBER 22, 2008
must be used. Assuming a moderate
115.5°C/W
97.1°C/W
500