參數(shù)資料
型號: MMQA27VT3
廠商: MOTOROLA INC
元件分類: TVS二極管 - 瞬態(tài)電壓抑制
英文描述: 150 W, UNIDIRECTIONAL, 4 ELEMENT, SILICON, TVS DIODE
封裝: PLASTIC, SC-59, 6 PIN
文件頁數(shù): 6/8頁
文件大?。?/td> 104K
代理商: MMQA27VT3
MOTOROLA
6
MMQA Series
The soldering temperature and time should not exceed
260
°C for more than 10 seconds.
When shifting from preheating to soldering, the
maximum temperature gradient should be 5
°C or less.
After soldering has been completed, the device should
be allowed to cool naturally for at least three minutes.
Gradual cooling should be used since the use of forced
cooling will increase the temperature gradient and will
result in latent failure due to mechanical stress.
Mechanical stress or shock should not be applied during
cooling.
TYPICAL SOLDER HEATING PROFILE
For any given circuit board, there will be a group of control
settings that will give the desired heat pattern. The operator
must set temperatures for several heating zones and a figure
for belt speed. Taken together, these control settings make
up a heating “profile” for that particular circuit board. On
machines controlled by a computer, the computer remem-
bers these profiles from one operating session to the next.
Figure 9 shows a typical heating profile for use when
soldering a surface mount device to a printed circuit board.
This profile will vary among soldering systems, but it is a
good starting point. Factors that can affect the profile include
the type of soldering system in use, density and types of
components on the board, type of solder used, and the type
of board or substrate material being used. This profile shows
temperature versus time. The line on the graph shows the
actual temperature that might be experienced on the surface
of a test board at or near a central solder joint. The two
profiles are based on a high density and a low density board.
The Vitronics SMD310 convection/infrared reflow soldering
system was used to generate this profile. The type of solder
used was 62/36/2 Tin Lead Silver with a melting point
between 177 –189
°C. When this type of furnace is used for
solder reflow work, the circuit boards and solder joints tend to
heat first. The components on the board are then heated by
conduction. The circuit board, because it has a large surface
area, absorbs the thermal energy more efficiently, then
distributes this energy to the components. Because of this
effect, the main body of a component may be up to 30
degrees cooler than the adjacent solder joints.
STEP 1
PREHEAT
ZONE 1
“RAMP”
STEP 2
VENT
“SOAK”
STEP 3
HEATING
ZONES 2 & 5
“RAMP”
STEP 4
HEATING
ZONES 3 & 6
“SOAK”
STEP 5
HEATING
ZONES 4 & 7
“SPIKE”
STEP 6
VENT
STEP 7
COOLING
200
°C
150
°C
100
°C
50
°C
TIME (3 TO 7 MINUTES TOTAL)
TMAX
SOLDER IS LIQUID FOR
40 TO 80 SECONDS
(DEPENDING ON
MASS OF ASSEMBLY)
205
° TO 219°C
PEAK AT
SOLDER JOINT
DESIRED CURVE FOR LOW
MASS ASSEMBLIES
100
°C
150
°C
160
°C
170
°C
140
°C
Figure 9. Typical Solder Heating Profile
DESIRED CURVE FOR HIGH
MASS ASSEMBLIES
相關PDF資料
PDF描述
MMQA33VT3 150 W, UNIDIRECTIONAL, 4 ELEMENT, SILICON, TVS DIODE
MMSZ3V9BW 3.9 V, 0.5 W, SILICON, UNIDIRECTIONAL VOLTAGE REGULATOR DIODE
MMSZ39VBW 39 V, 0.5 W, SILICON, UNIDIRECTIONAL VOLTAGE REGULATOR DIODE
MMSZ9V1BW 9.1 V, 0.5 W, SILICON, UNIDIRECTIONAL VOLTAGE REGULATOR DIODE
MMSZ36VBW 36 V, 0.5 W, SILICON, UNIDIRECTIONAL VOLTAGE REGULATOR DIODE
相關代理商/技術參數(shù)
參數(shù)描述
MMQA30V 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Direct ProTek Replacement:SMS24 |Alternative ProTek Replacement:PSMS36
MMQA30VT1 功能描述:TVS二極管陣列 30V 150W TVS Quad RoHS:否 制造商:Littelfuse 極性: 通道:4 Channels 擊穿電壓: 鉗位電壓:11.5 V 工作電壓:2.5 V 峰值浪涌電流:20 A 安裝風格:SMD/SMT 端接類型:SMD/SMT 系列: 最小工作溫度:- 40 C 最大工作溫度:+ 85 C
MMQA30VT1G 功能描述:TVS二極管陣列 30V 150W TVS Quad Array RoHS:否 制造商:Littelfuse 極性: 通道:4 Channels 擊穿電壓: 鉗位電壓:11.5 V 工作電壓:2.5 V 峰值浪涌電流:20 A 安裝風格:SMD/SMT 端接類型:SMD/SMT 系列: 最小工作溫度:- 40 C 最大工作溫度:+ 85 C
MMQA30VT3 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:SC-74 Quad Monolithic Common Anode
MMQA33V 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Direct ProTek Replacement:SMS24 |Alternative ProTek Replacement:PSMS36