ICS8440258AK-46LF IDT, Integrated Device Technology Inc, ICS8440258AK-46LF Datasheet - Page 12

• Manufacturer Part Number: ICS8440258AK-46LF
• Description: IC SYNTHESIZER 8OUTPUT 32-VFQFPN
• Manufacturer: IDT, Integrated Device Technology Inc
• Series: HiPerClockS™, FemtoClock®r
• Type: Frequency Synthesizerr

Specifications of ICS8440258AK-46LF

• Pll: Yes with Bypass
• Input: LVCMOS, LVTTL, Crystal
• Output: LVCMOS, LVDS, LVTTL
• Number Of Circuits: 1
• Ratio - Input:output: 2:8
• Differential - Input:output: No/Yes
• Frequency - Max: 125MHz
• Divider/multiplier: Yes/No
• Voltage - Supply: 2.375 V ~ 2.625 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 32-VFQFN
• Frequency-max: 125MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 8440258AK-46LF

T
IDT
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
Assuming no air flow and a multi-layer board, the appropriate value is 37°C/W per Table 6.
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).
ABLE
ICS8440258-46
FEMTOCLOCK™ CRYSTAL/LVCMOS-TO-LVDS/ LVCMOS FREQUENCY SYNTHESIZER
™
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 + 0.519W * 37°C/W = 89.2°C. This is below the limit of 125°C.
/ ICS
JA
A
6. T
= Ambient Temperature
= Junction-to-Ambient Thermal Resistance
™
Multi-Layer PCB, JEDEC Standard Test Boards
LVDS/LVCMOS FREQUENCY SYNTHESIZER
HERMAL
R
ESISTANCE
θ θ θ θ θ
JA
FOR
32-L
θ θ θ θ θ
JA
JA
EAD
* Pd_total + T
vs. Air Flow (Meters per Second)
VFQFN, F
A
ORCED
12
37.0°C/W
C
ONVECTION
0
32.4°C/W
1
ICS8440258AK-46 REV B JANUARY 15, 2008
TM
devices is 125°C.
JA
29.0°C/W
must be used.
2.5
PRELIMINARY