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參數(shù)資料
| 型號(hào)： | SC615AMLTRT |
| 廠商： | Semtech Corporation |
| 英文描述： | Charge Pump Flash LED Driver |
| 中文描述： | 電荷泵閃光LED驅(qū)動(dòng)器 |
| 文件頁(yè)數(shù)： | 6/12頁(yè) |
| 文件大?。?/td> | 216K |
| 代理商： | SC615AMLTRT |
6
2005 Semtech Corp.
www.semtech.com
POWER MANAGEMENT
Applications Information (Cont.)
SC615A
Over-Temperature Protection
The over-temperature circuit helps prevent the device
from overheating and experiencing a catastrophic fail-
ure. When the junction temperature exceeds 150°C the
device is disabled. It remains disabled until the junction
temperature drops below this threshold. As with the UVLO
and OVP circuits, hysteresis is included to prevent tog-
gling between modes.
Over-Current Protection
When the SC615A is in 2X charge pump mode, the input
current will be approximately double the required output.
When the steady-state load requires the maximum cur-
rent available in 2X mode, the OCP circuit prevents the
device from overheating due to excessive power dissipa-
tion.
Short-Circuit Current Protection
Short-circuit current protection is provided to limit the
current that can be sourced when the output is shorted
to ground. When a short circuit forces V
to drop below
2V, the SCCP detects the condition and limits the output
current.
Resistor Selection
The ISET resistor selection is critical in generating the
correct current. The value can be chosen to set the Spot-
light mode current or the Flash mode current, but it must
be noted that the two current settings are dependent on
the same resistor. It is recommended that the resistor
be selected to match the desired LED current for Flash
mode. This allows the designer to set the SC615A’s maxi-
mum current and select the package size necessary for
the power dissipation required in Flash mode. The typi-
cal application shown on page 1 uses a 0.5
resistor to
set a flash mode current of 500mA and spotlight mode
current of 200mA. A high precision resistor should be
used to ensure the specified accuracy for LED current.
To avoid malfunction of the charge pump, it is recom-
mended that the resistance seen at the ISET pin remain
constant while the device is active (Flash or Spotlight
mode). Changing the resistance value or the load cur-
rent while the device is active could cause instability that
would result in non-compliant behavior.
The load current return path is from the ISET sense point
through the resistor and back to the ground pins. Resis-
tance in this path adds to the total resistance and has
the effect of reducing the LED current by about 4% per
10mV of DC drop across the return copper trace in flash
mode. For this reason, it is crucial to have a low resis-
tance return path. Place and ground the resistor as close
as possible to the ground pin of the SC615A. The trace
from the ISET pin has virtually no current. The ISET trace
should make contact at the pad of the power sense re-
sistor to minimize the effect of voltage drop between
the LED cathode and the resistor.
Capacitor Selection
The SC615A is designed to use low-ESR ceramic capaci-
tors for the input and output bypass capacitors as well
as the charge pump bucket capacitors. Ideal perfor-
mance is achieved when C1 is exactly equal to C2. It is
recommended that X5R or X7R ceramic capacitors be
used for best performance.
Thermal Resistance
The SC615A package is thermally efficient when the cir-
cuit board layout connects the thermal pad though mul-
tiple vias to the ground plane. The thermal resistance is
rated at 49°C/W and this rating is dependent on the
connection between the thermal pad and the ground
plane. A layout that is done correctly should keep the
junction temperature below the OT limit while operating
the SC615A within the specified electrical conditions for
I
and V
. A poor layout may allow the junction tem-
perature to reach the OT limit while in Flash or Spotlight
mode. So, it is critical to maintain adequate ground plane
around the device to maximize heat transfer and avoid
over-temperature shutdown.
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相關(guān)代理商/技術(shù)參數(shù) |
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| SC615EVB | 制造商:SEMTECH 制造商全稱:Semtech Corporation 功能描述:Charge Pump Flash LED Driver |
| SC615IMLTRT | 制造商:Semtech Corporation 功能描述:LED DRVR 1Segment 3.3V/5V 10-Pin MLPD T/R |
| SC616CP | 功能描述:音頻指示器及警報(bào)器 MEDIUM CHIME 6-16V RoHS:否 制造商:PUI Audio 產(chǎn)品:Indicators 聲壓級(jí):85 dB 音調(diào):Continuous 頻率:2300 Hz +/- 300 Hz 電壓額定值:5 VDC 電流額定值:30 mA 端接類型: 直徑:12 mm 安裝:Through Hole |
| SC616CP-BTR | 功能描述:DC Buzzer Chime 2.9kHz Piezo 6 ~ 16V 68dB @ 6V, 61cm 制造商:mallory sonalert products inc. 系列:SC 包裝:散裝 零件狀態(tài):有效 驅(qū)動(dòng)器電路:指示燈，內(nèi)部驅(qū)動(dòng) 輸入類型:DC 電壓 - 額定:- 電壓范圍:6 ~ 16V 頻率:2.9kHz 技術(shù):壓電 工作模式:和諧 持續(xù)時(shí)間:- 聲壓級(jí):68dB @ 6V，61cm 電流 - 電源:6 ~ 23mA 端口位置:頂部 工作溫度:-30°C ~ 65°C 認(rèn)可:cUL，UL 等級(jí):- 安裝類型:面板安裝 端接:快速連接接片 - 0.250"（6.35mm） 大小/尺寸:42.9mm 直徑 高度 - 安裝（最大值）:* 標(biāo)準(zhǔn)包裝:1 |
| SC616CPN | 功能描述:音頻指示器及警報(bào)器 CHIME, 6-16VDC 2900HZ, CUL APPRVD RoHS:否 制造商:PUI Audio 產(chǎn)品:Indicators 聲壓級(jí):85 dB 音調(diào):Continuous 頻率:2300 Hz +/- 300 Hz 電壓額定值:5 VDC 電流額定值:30 mA 端接類型: 直徑:12 mm 安裝:Through Hole |
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