- 您現在的位置：買賣IC網 > Datasheet目錄46 > SC427MLTRT (Semtech)IC REG DL BUCK/LINEAR 32MLPQ Datasheet資料下載
參數資料
| 型號： | SC427MLTRT |
| 廠商： | Semtech |
| 文件頁數： | 19/33頁 |
| 文件大?。?/td> | 894K |
| 描述： | IC REG DL BUCK/LINEAR 32MLPQ |
| 標準包裝： | 1 |
| 系列： | EcoSpeed®, SmartDrive™ |
| 拓撲： | 降壓（降壓）（1），線性（LDO）（1） |
| 功能： | 任何功能 |
| 輸出數： | 2 |
| 頻率 - 開關： | 1MHz |
| 電壓/電流 - 輸出 1： | 可調，10A |
| 電壓/電流 - 輸出 2： | 5V，200mA |
| 帶 LED 驅動器： | 無 |
| 帶監控器： | 無 |
| 帶序列發生器： | 無 |
| 電源電壓： | 3 V ~ 28 V |
| 工作溫度： | -40°C ~ 85°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 32-VFQFN 裸露焊盤 |
| 供應商設備封裝： | 32-MLPQ（5x5） |
| 包裝： | 標準包裝 |
| 其它名稱： | SC427MLDKR |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁當前第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁
SC417/SC427
19
FB Ripple
Voltage (V
FB
)
FB threshold
(500mV)
Inductor
Current
DH
DL
(0A)
40祍 time-out
minimum f
SW
~ 25kHz
After the 40祍ec time-out, DL drives high if V
FB
has not reached the FB threshold.
DH On-time is triggered when
V
FB
reaches the FB Threshold
On-time
(T
ON
)
Figure 5 Ultrasonic Power-save Operation
Power-save Mode Operation (SC427)
The SC427 provides power-save operation at light loads
with no minimum operating frequency. With power-save
enabled, the internal zero crossing comparator monitors
the inductor current via the voltage across the low-side
MOSFET during the off-time. If the inductor current falls to
zero for 8 consecutive switching cycles, the controller
enters power-save operation. It will turn off the low-side
MOSFET on each subsequent cycle provided that the
current crosses zero. At this time both MOSFETs remain
off until V
FB
drops to the 500mV threshold. Because the
MOSFETs are off, the load is supplied by the output capaci-
tor. If the inductor current does not reach zero on any
switching cycle, the controller immediately exits power-
save and returns to forced continuous mode. Figure 6
shows power-save operation at light loads.
FB Ripple
Voltage
(V
FB
)
FB threshold
DL
DH
Inductor
Current
Zero (0A)
DH On-time is triggered when
V
FB
reaches the FB Threshold.
(500mV)
On-time (T
ON
)
DL drives high when on-time is completed.
DL remains high until inductor current reaches zero.
Dead time varies
according to load
Figure 6 Power-save Operation
Smart Power-save Protection
Active loads may leak current from a higher voltage into
the switcher output. Under light load conditions with
power-save enabled, this can force V
OUT
to slowly rise and
reach the over-voltage threshold, resulting in a hard shut-
down. Smart power-save prevents this condition. When
the FB voltage exceeds 10% above nominal (exceeds
550mV), the device immediately disables power-save, and
DL drives high to turn on the low-side MOSFET. This draws
current from V
OUT
through the inductor and causes V
OUT
to
fall. When V
FB
drops back to the 500mV trip point, a normal
T
ON
switching cycle begins. This method prevents a hard
OVP shutdown and also cycles energy from V
OUT
back to
V
IN
. It also minimizes operating power by avoiding forced
conduction mode operation. Figure 7 shows typical wave-
forms for the Smart Power-save feature.
SmartDrive
TM
For each DH pulse the DH driver initially turns on the high-
side MOSFET at a lower speed, allowing a softer, smooth
turn-off of the low-side diode. Once the diode is off and
the LX voltage has risen 0.5V above PGND, the SmartDrive
circuit automatically drives the high-side MOSFET on at a
rapid rate. This technique reduces switching while main-
taining high efficiency and also avoids the need for snub-
bers or series resistors in the gate drive.
Applications Information (continued)
相關PDF資料 |
PDF描述 |
|---|---|
| SE95D,112 | IC SENSOR TEMP 2.8-5.5V SOT96-1 |
| SE97BTP,547 | IC TEMP SENSOR DIMM 8HWSON |
| SE98ATP,547 | IC TEMP SENSOR DDR 8-HWSON |
| SG6901ASZ | IC PFC CTLR AVERAGE CURR 20SOIC |
| SG6932SZ | IC PFC CONTROLLER CCM 16SOP |
相關代理商/技術參數 |
參數描述 |
|---|---|
| SC428 | 制造商:Mallory 功能描述:Sonalert |
| SC4-28 | 功能描述:SCREW 4-40 HEX .5"L FOR CONN MNT RoHS:是 類別:盒，外殼，支架 >> 卡架 - 配件 系列:VectorPak™ 標準包裝:1 系列:VectorPak™ 附件類型:EFP 模塊 適用于相關產品:PCB |
| SC428312CFGE | 制造商:Freescale Semiconductor 功能描述: |
| SC42920FNR2 | 制造商:Motorola Inc 功能描述: |
| SC430769CFNER | 制造商:Freescale Semiconductor 功能描述:SMOKE DETECTOR |
發布緊急采購，3分鐘左右您將得到回復。