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參數(shù)資料
| 型號(hào)： | 2557 |
| 廠商： | Allegro MicroSystems, Inc. |
| 英文描述： | PROTECTED QUAD LOW-SIDE DRIVER WITH FAULT DETECTION & SLEEP MODE |
| 中文描述： | 保護(hù)四低側(cè)驅(qū)動(dòng)與故障檢測(cè) |
| 文件頁(yè)數(shù)： | 7/12頁(yè) |
| 文件大?。?/td> | 176K |
| 代理商： | 2557 |
2557
PROTECTED QUAD DRIVER
WITH FAULT DETECTION
& SLEEP MODE
www.allegromicro.com
7
CIRCUIT DESCRIPTION AND APPLICATION (continued)
NORMAL LOAD
TIME
Dwg. WP-013-1
NOT TO SCALE
O
CURRENT LIMIT (12 V SUPPLY)
SHORT CIRCUIT
CURRENT LIMIT (24 V SUPPLY)
IN
FAULT
(SHORTED
LOAD)
FAULT
(OPEN
LOAD)
WITH OUTPUT CAPACITOR
Dwg. WP-035
Thermal considerations
Device power dissipation can be calculated as:
P
D
= (V
O1
x I
O1
x duty cycle
1
) + … + (V
O4
x I
O4
x duty cycle
4
)
+ (V
CC
x I
CC
)
Note - I
CC
is also modulated by the duty cycle, but this is a
reasonable approximation for most purposes.
This can then be compared against the permitted package
power dissipation, using:
Permitted P
D
= (150 – T
A
)/R
θ
JA
where R
θ
JA
is given as:
28-lead PLCC (part number suffix ‘–EB’) = 36
°
C/W
16-pin PDIP (part number suffix ‘–B’) =
16-lead SOIC (part number suffix ‘–LB’) = 60
°
C/W
43
°
C/W
The thermal resistance from junction to power tab (R
θ
JT
) is
about 6
°
C/W for the three package types, therefore the power
dissipation can be improved by 20% to 30% by adding an area
of printed wiring board copper (typically 6 to 18 square
centimetres) connected to the power-tab GROUND terminals of
the device.
Under some conditions it is possible to get spurious
glitches on the FAULT output at load turn-on and turn-off
transitions:
turn-off delay (see characteristics above) of the output stage
increases and may result in a spurious fault output of a few
μ
s
(the duration being proportional to the turn-off delay). As it is
difficult to define this over all operating conditions, if a
particular application would be sensitive to this type of glitch,
then it is generally recommended to include a small (about
0.01
μ
F) smoothing/storage capacitor at the FAULT output.
Light load turn-off. Under light loading conditions the
incandescent filament results in the driver operating in current
limit for a period after turn-on. During this period a “fault”
condition will be indicated (over current). As discussed above
this period can be 10s of ms. To avoid this indication, the
capacitor on the FAULT output would need to be increased to
provide an appropriate time constant. Alternatively, in a
microcontroller-based system, the code could be written to
ignore the FAULT condition for an appropriate period after
lamp turn on.
Incandescent lamp turn-on. As described above, driving an
Correct FAULT operation cannot be guaranteed with an
unconnected output — unused outputs should not be turned on,
or
unused outputs should be pulled high to >2.5 V,
and/or
associated inputs tied low.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| 2557.000.00 | 功能描述:ID NET.24V-B POWER SUPPLY UNIT RoHS:是 類別:RF/IF 和 RFID >> RFID配件 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 附件類型:WLAN-A 無(wú)線適配器 適用于相關(guān)產(chǎn)品:629-1002-ND、629-1045-ND、629-1046-ND、LRU2000 讀取器 其它名稱:2421.000.01.00629-1048DCF-660W |
| 2557_06 | 制造商:ALLEGRO 制造商全稱:Allegro MicroSystems 功能描述:PROTECTED QUAD LOW-SIDE DRIVER WITH FAULT DETECTION and SLEEP MODE |
| 255-700 | 制造商:WAGO 功能描述:LT GREEN END PLATE |
| 25-5702-10SW | 功能描述:SUPPLIED AIR RESPIRATORY PROTECT 制造商:3m 系列:* 零件狀態(tài):在售 標(biāo)準(zhǔn)包裝:1 |
| 25-5702-20SW | 功能描述:SUPPLIED AIR RESPIRATORY PROTECT 制造商:3m 系列:* 零件狀態(tài):在售 標(biāo)準(zhǔn)包裝:1 |
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