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參數(shù)資料
| 型號： | ATF-521P8-BLK |
| 元件分類： | 小信號晶體管 |
| 英文描述： | L BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET, MO-229 |
| 封裝： | 2 x 2 MM, 0.75 MM HEIGHT,LEAD FREE, PLASTIC,LPCC-8 |
| 文件頁數(shù)： | 13/23頁 |
| 文件大?。?/td> | 319K |
| 代理商： | ATF-521P8-BLK |
20
Using the 3GPP standards document Release 1999
version 20026, the following channel configuration
was used to test ACLR. This table contains the power
levels of the main channels used for Test Model 1.
Note that the DPCH can be made up of 16, 32, or 64
separate channels each at different power levels and
timing offsets. For a listing of power levels, channeliza
tion codes and timing offset see the entire 3GPP TS
25.141 V3.10.0 (200206) standards document at: http://
www.3gpp.org/specs/specs.htm
Table 3. ACLR Channel Power Configuration.
3GPP TS 25.141 V3.10.0 (2002-06) Type
Pwr (dB)
PCCPCH+SCH
10
Primary CPICH
10
PICH
18
SCCPCH containing PCH (SF=256)
18
DPCH64ch (SF=128)
1.1
Thermal Design
When working with medium to high power FET
devices, thermal dissipation should be a large part
of the design. This is done to ensure that for a given
ambient temperature the transistor’s channel does not
exceed the maximum rating, T
CH, on the data sheet.
For example, ATF521P8 has a maximum channel tem
perature of 150°C and a channel to board thermal
resistance of 45°C/W, thus the entire thermal design
hinges from these key data points. The question that
must be answered is whether this device can operate
in a typical environment with ambient temperature
fluctuations from 25°C to 85°C. From Figure 19, a very
useful equation is derived to calculate the temperature
of the channel for a given ambient temperature. These
calculations are all incorporated into Avago Technolo
gies AppCAD.
where,
θ
b–a is the board to ambient thermal resistance;
θ
ch–b is the channel to board thermal resistance.
The board to ambient thermal resistance thus becomes
very important for this is the designer’s major source
of heat control. To demonstrate the influence of θ
ba,
thermal resistance is measured for two very different
scenarios using the ATF521P8 demoboard. The first
case is done with just the demoboard by itself. The
second case is the ATF demoboard mounted on a
chassis or metal casing, and the results are given below:
Table 4. Thermal resistance measurements.
ATF Demoboard
θ
b-a
PCB 1/8" Chassis
10.4°C/W
PCB no HeatSink
32.9°C/W
Therefore calculating the temperature of the channel
for these two scenarios gives a good indication of what
type of heat sinking is needed.
Case 1: Chassis Mounted @ 85°C
Tch = P x (θ
chb + θba) + Ta
=.9W x (45+10.4)°C/W +85°C
Tch = 135°C
Case 2: No Heatsink @ 85°C
Tch = P x (θ
chb + θba) + Ta
=.9W x (45+32.9)°C/W + 85°C
Tch = 155°C
In other words, if the board is mounted to a chassis, the
channel temperature is guaranteed to be 135°C safely
below the 150°C maximum. But on the other hand, if
no heat sinking is used and the θ
ba is above 27°C/W
(32.9°C/W in this case), then the power must be derated
enough to lower the temperature below 150°C. This can
be better understood with Figure 20 below. Note power
is derated at 13 mW/°C for the board with no heat sink
and no derating is required for the chassis mounted
board until an ambient temperature of 100°C.
θch-b
Tch
(channel)
Tb (board
or belly
of the part)
Ta (ambient)
Ts (sink)
Pdiss
=
Vds
x
Ids
θb-s
θs-a
Figure 19. Equivalent Circuit for Thermal Resistance.
Hence very similar to Ohms Law, the temperature of the
channel is calculated with equation 8 below.
T
CH = Pdiss (θch–b + θb–s + θs–a ) + Tamb
(8)
If no heat sink is used or heat sinking is incorporated
into the PCB board then equation 8 may be reduced to:
T
CH = Pdiss (θch–b + θb–a ) + Tamb (9)
Pdiss
(W)
0.9W
0
81 100
150
Tamb (
°C)
No Heatsink
(13 mW/
°C)
Mounted on Chassis
(18 mW/
°C)
Figure 20. Derating for ATF- 521P8.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ATF-53189-TR1 | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET |
| ATF-53189-BLK | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET |
| ATF-531P8-BLK | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET, MO-229 |
| ATF-531P8-TR1G | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET, MO-229 |
| ATF-531P8-TR1G | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET, MO-229 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ATF-521P8-BLK | 制造商:Avago Technologies 功能描述:RF Bipolar Transistor |
| ATF-521P8-BLKG | 制造商:Avago Technologies 功能描述: |
| ATF-521P8-TR1 | 功能描述:射頻GaAs晶體管 Transistor GaAs High Linearity RoHS:否 制造商:TriQuint Semiconductor 技術(shù)類型:pHEMT 頻率:500 MHz to 3 GHz 增益:10 dB 噪聲系數(shù): 正向跨導(dǎo) gFS（最大值/最小值）:4 S 漏源電壓 VDS: 閘/源擊穿電壓:- 8 V 漏極連續(xù)電流:3 A 最大工作溫度:+ 150 C 功率耗散:10 W 安裝風(fēng)格: 封裝 / 箱體: |
| ATF-521P8-TR2 | 功能描述:射頻GaAs晶體管 Transistor GaAs High Linearity RoHS:否 制造商:TriQuint Semiconductor 技術(shù)類型:pHEMT 頻率:500 MHz to 3 GHz 增益:10 dB 噪聲系數(shù): 正向跨導(dǎo) gFS（最大值/最小值）:4 S 漏源電壓 VDS: 閘/源擊穿電壓:- 8 V 漏極連續(xù)電流:3 A 最大工作溫度:+ 150 C 功率耗散:10 W 安裝風(fēng)格: 封裝 / 箱體: |
| ATF524S16M | 制造商:n/a 功能描述:Inverter Semiconductor |
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