参数资料
| 型号： | SC171MLTRT |
| 厂商： | Semtech |
| 文件页数： | 12/27页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 1A 10MLPD |
| 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： | 1A |
| 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： | SC171MLDKR |
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SC171
Applications Information (continued)
Enable and Power-save Inputs
The EN/PSV input is used to enable or disable the switch-
FB
REF
V OUT
V IN
PWM
-
+
On-Shot Timing
Generator
S
R
Q
Hi-Side
and
Lo-Side
Gate
Drivers
V IN
Q1
V LX
Q2
LPF
L
ESR
C OUT
+
V OUT
FB
ing regulator. When EN/PSV is low (grounded), the switch-
ing regulator is off and in its lowest power state. When
off, the output power switches are tri-stated. When EN/
PSV is allowed to float, the pin voltage will float to 41%
of the voltage at V DD . The switching regulator turns on
with power-save disabled and all switching is in forced
R TON
Time = K x V OUT /V IN
continuous mode.
R TON
= ( OUT ) ?
Figure2—On-TimeGeneration
The SC171 uses an external resistor to set the on-time
which indirectly sets the frequency. The on-time can
be programmed to provide operating frequency from
200kHz to 1MHz using a resistor between the TON pin
and ground. The resistor value is selected by the fol-
lowing equation.
V 1
V FB 100pF ? f SW
V OUT Voltage Selection
The switcher output voltage is regulated by comparing
V OUT as seen through a resistor divider at the FB pin to
the internal 750mV reference voltage, see Figure 3.
When EN/PSV is high (above 60% of the voltage at V DD ),
the switching regulator turns on with ultrasonic power-
save enabled. The SC171 ultrasonic power-save opera-
tion maintains a minimum switching frequency of 25kHz,
for applications with stringent audio requirements.
Forced Continuous Mode Operation
The SC171 operates in Forced Continuous Mode (FCM)
by floating the EN/PSV pin (see Figure 4). In this mode
one of the power MOSFETs is always on, with no inten-
tional dead time other than to avoid cross-conduction.
This feature results in uniform frequency across the full
load range with the trade-off being poor efficiency at
light loads due to the high-frequency switching of the
MOSFETs.
V OUT
To FB pin
FB Ripple
Voltage (V FB )
FB threshold
(750mV)
R 1
R 2
Figure 3 — Output Voltage Selection
Inductor
Current
DC Load Current
Note that this control method regulates the valley of the
output ripple voltage, not the DC value. The DC output
voltage V OUT is offset by the output ripple according to
the following equation.
DH
On-time
(T ON )
DH on-time is triggered when
V FB reaches the FB Threshold.
= 0.75V ? ? ? 1 +
R 1 ? V
R 2 ? ?
V OUT
?
?
? + RIPPLE
2
DL
DL drives high when on-time is completed.
DL remains high until V FB falls to the FB threshold.
Figure 4 — Forced Continuous Mode Operation
? 2010 Semtech Corporation
12
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SC172 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:2A EcoSpeedTM Synchronous Step-Down Regulator with Optional Ultrasonic Power Save |
| SC17-2 | 制造商:Thomas & Betts 功能描述:DRIVE RING - 1 1/4" |
| SC172MLTRT | 制造商:Semtech Corporation 功能描述:Conv DC-DC Single Step Down 3V to 5.5V 10-Pin MLPD EP T/R 制造商:Semtech Corporation 功能描述:IC DC-DC CONV 1MHz 10-MLPD 制造商:Semtech Corporation 功能描述:IC, DC-DC CONV, 1MHz, 10-MLPD 制造商:Semtech Corporation 功能描述:SC172 Series 5.5 V 1 MHz 2 A Synchronous EcoSpeed Step-Down Regulator - MLPD-10 制造商:Semtech Corporation 功能描述:IC, DC-DC CONV, 1MHz, 10-MLPD; Primary Input Voltage:5.5V; No. of Outputs:1; Output Voltage:5.225V; Output Current:2A; No. of Pins:10; Operating Temperature Min:-40C; Operating Temperature Max:85C; Package / Case:10-MLPD 制造商:SEMTECH 功能描述:SC172 Series 5.5 V 1 MHz 2 A Synchronous EcoSpeed Step-Down Regulator - MLPD-10 |
| SC173 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:3A EcoSpeedTM Synchronous Step-Down Regulator with Optional Ultrasonic Power Save |
| SC173A | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:3A EcoSpeedTM Synchronous Step-Down Regulator with Automatic Power Save |
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