ICS85310AYI-21LN IDT, Integrated Device Technology Inc, ICS85310AYI-21LN Datasheet - Page 10

• Manufacturer Part Number: ICS85310AYI-21LN
• Description: IC FANOUT BUFFER 1-5 DUAL 32LQFP
• Manufacturer: IDT, Integrated Device Technology Inc
• Series: HiPerClockS™r
• Type: Fanout Buffer (Distribution)r

Specifications of ICS85310AYI-21LN

• Number Of Circuits: 2
• Ratio - Input:output: 1:5
• Differential - Input:output: Yes/Yes
• Input: HCSL, LVDS, LVHSTL, LVPECL, SSTL
• Output: ECL, LVPECL
• Frequency - Max: 700MHz
• Voltage - Supply: 2.375 V ~ 3.8 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 32-LQFP
• Frequency-max: 700MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 85310AYI-21LN

This section provides information on power dissipation and junction temperature for the ICS85310I-21.
Equations and example calculations are also provided.
1. Power Dissipation.
The total power dissipation for the ICS85310I-21 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 the devices is 125°C.
In order to calculate junction temperature, the appropriate junction-to-ambient thermal resistance θ
moderate air flow of 200 linear feet per minute and a multi-layer board, the appropriate value is 42.1°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
85310AYI-21
ABLE
•
•
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 + 0.756W * 42.1°C/W = 116.8°C. This is below the limit of 125°C
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.
JA
A
= Ambient Temperature
6. T
= Junction-to-Ambient Thermal Resistance
Power (core)
Power (outputs)
If all outputs are loaded, the total power is 10 * 30mW = 300mW
Total Power
HERMAL
R
MAX
ESISTANCE
_MAX
MAX
= V
(3.8V, with all outputs switching) = 456mW + 300mW = 756mW
= 30mW/Loaded Output pair
CC_MAX
θ θ θ θ θ
* I
JA
EE_MAX
FOR
D
θ θ θ θ θ
JA
IFFERENTIAL
P
CC
32-
= 3.8V * 120mA = 456mW
JA
by Velocity (Linear Feet per Minute)
= 3.8V, which gives worst case results.
* Pd_total + T
OWER
PIN
LQFP, F
C
www.idt.com
-
A
TO
ONSIDERATIONS
ORCED
-2.5V/3.3V ECL/LVPECL F
10
C
ONVECTION
67.8°C/W
47.9°C/W
0
L
55.9°C/W
42.1°C/W
OW
200
JA
ICS85310I-21
S
must be used . Assuming a
KEW
, D
ANOUT
REV. E AUGUST 13, 2010
UAL
50.1°C/W
39.4°C/W
500
, 1-
B
UFFER
TO
-5