参数资料
| 型号： | SC173MLTRT |
| 厂商： | Semtech |
| 文件页数： | 13/27页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 3A 10MLPD |
| 产品培训模块： | Power Supplies 101 |
| 标准包装： | 1 |
| 系列： | EcoSpeed® |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.75 V ~ 5.23 V |
| 输入电压： | 3 V ~ 5.5 V |
| 频率 - 开关： | 200kHz ~ 1MHz |
| 电流 - 输出： | 3A |
| 同步整流器： | 是 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 10-VFDFN 裸露焊盘 |
| 包装： | 标准包装 |
| 供应商设备封装： | 10-MLPD（3x3） |
| 其它名称： | SC173MLDKR |
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SC173
Smart Power Save
ApplicationsInformation(continued)
Ultrasonic Power Save Operation
The SC173 provides ultrasonic power save operation at
light loads, with the minimum operating frequency fixed
at 25kHz. This is accomplished using an internal timer
that monitors the time between consecutive high-side
gate pulses. If the time exceeds 40μs, DL drives high to
turn the low-side MOSFET on. This draws current from
V OUT through the inductor, forcing both V OUT and V FB to
fall. When V FB drops to the 750mV threshold, the next DH
on-time is triggered. After the on-time is completed the
high-side MOSFET is turned off and the low-side MOS-
FET turns on. The low-side MOSFET remains on until the
inductor current ramps down to zero, at which point the
low-side MOSFET is turned off.
Because the on-times are forced to occur at intervals
no greater than 40μs, the frequency will not fall below
~25kHz. Figure 5 shows ultrasonic power save opera-
tion.
power save enabled, this can force V OUT to slowly rise
and reach the over-voltage threshold, resulting in a hard
shutdown. Smart power save prevents this condition.
When the FB voltage exceeds 10% above nominal (ex-
ceeds 825mV), 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 750mV 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 . Figure 6 shows typical waveforms
for the Smart Power Save feature.
V OUT drifts up to due to leakage
current flowing into C OUT V OUT discharges via inductor
and low-side MOSFET
Threshold (825mV)
Normal V OUT ripple
FB
threshold
DH and DL off
High-side
Drive (DH)
Single DH on-time pulse
after DL turn-off
Low-side
Drive (DL)
V OUT drifts up to due to leakage
current flowing into C OUT
Smart Power Save
Threshold (825mV)
FB
threshold
DH and DL off
High-side
Drive (DH)
Single DH on-time pulse
after DL turn-off
Low-side
Drive (DL)
DL turns on when Smart
PSAVE threshold is reached
DL turns off when FB
threshold is reached
V OUT discharges via inductor
and low-side MOSFET
Normal V OUT ripple
Normal DL pulse after DH
on-time pulse
DL turns on when Smart Normal DL pulse after DH
PSAVE threshold is reached on-time pulse
DL turns off when FB
threshold is reached
Figure 6 — Smart Power Save
Current Limit Protection
The device features fixed current limiting, which is ac-
complished by using the R DS(ON) of the lower MOSFET for
current sensing. While the low-side MOSFET is on, the
inductor current flows through it and creates a voltage
across the R DS(ON) . During this time, the voltage across the
MOSFET is negative with respect to ground. During this
time, If this MOSFET voltage drop exceeds the internal
reference voltage, the current limit will activate. The cur-
rent limit then keeps the low-side MOSFET on and will
not allow another high side on-time, until the current in
Figure 5 — Ultrasonic 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
? 2010 Semtech Corporation
the low-side MOSFET reduces enough to drop below the
internal reference voltage once more. This method regu-
lates the inductor valley current at the level shown by I LIM
in Figure 7.
13
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SC174 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:4A EcoSpeedTM Synchronous Step-Down Regulator with Optional Ultrasonic Power Save |
| SC1743 | 制造商:ROEBUCK 功能描述:HAND STRETCH FILM |
| SC174EVB | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:4A EcoSpeedTM Synchronous Step-Down Regulator with Optional Ultrasonic Power Save |
| SC174ML.TRT | 制造商:Semtech Corporation 功能描述: |
| SC174MLTRT | 功能描述:IC REG BUCK SYNC ADJ 4A 10MLPD RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:EcoSpeed® 标准包装:250 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V 输入电压:2.05 V ~ 6 V PWM 型:电压模式 频率 - 开关:2MHz 电流 - 输出:500mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:6-UFDFN 包装:带卷 (TR) 供应商设备封装:6-SON（1.45x1） 产品目录页面:1032 (CN2011-ZH PDF) 其它名称:296-25628-2 |
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