ICS85304AG-01LFT IDT, Integrated Device Technology Inc, ICS85304AG-01LFT Datasheet - Page 10

• Manufacturer Part Number: ICS85304AG-01LFT
• Description: IC FANOUT BUFFER 1-5 20-TSSOP
• Manufacturer: IDT, Integrated Device Technology Inc
• Type: Fanout Buffer (Distribution), Multiplexerr
• Series: HiPerClockS™r

Specifications of ICS85304AG-01LFT

• Number Of Circuits: 1
• Ratio - Input:output: 2:5
• Differential - Input:output: Yes/Yes
• Input: HCSL, LVDS, LVHSTL, LVPECL, SSTL
• Output: LVPECL
• Frequency - Max: 650MHz
• Voltage - Supply: 3.135 V ~ 3.465 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 20-TSSOP
• Frequency-max: 650MHz
• Number Of Clock Inputs: 2
• Mode Of Operation: Differential
• Output Frequency: 650MHz
• Output Logic Level: LVPECL
• Operating Supply Voltage (min): 3.135V
• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (max): 3.465V
• Package Type: TSSOP
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 20
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 85304AG-01LFT

Power Considerations
This section provides information on power dissipation and junction temperature for the ICS85304-01.
Equations and example calculations are also provided.
1.
The total power dissipation for the ICS85304-01 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
and a multi-layer board, the appropriate value is 73.2°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).
Table 6. Thermal Resistance
IDT™ / ICS™ 3.3V LVPECL FANOUT BUFFER
Linear Feet per Minute
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.
ICS85304-01
LOW SKEW, 1-TO-5 DIFFERENTIAL-TO- 3.3V LVPECL FANOUT BUFFER
Power Dissipation.
•
•
Power (core)
Power (outputs)
If all outputs are loaded, the total power is 5 * 30.2mW = 151mW
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 + 0.342W * 73.2°C/W = 95°C. This is well below the limit of 125°C.
JA
A
= Ambient Temperature
= Junction-to-Ambient Thermal Resistance
MAX
(3.465V, with all outputs switching) = 190.57mW + 151mW = 341.57mW
MAX
MAX
= V
= 30.2mW/Loaded Output pair
CC_MAX
θ
JA
* I
for 20 Lead TSSOP, Forced Convection
EE_MAX
CC
= 3.3V + 5% = 3.465V, which gives worst case results.
JA
= 3.465V * 55mA = 190.57mW
* Pd_total + T
θ
JA
114.5°C/W
73.2°C/W
A
by Velocity
0
10
98.0°C/W
66.6°C/W
200
JA
must be used. Assuming no air flow
ICS85304AG-01 REV. E JULY 8, 2008
88.0°C/W
63.5°C/W
500