参数资料
| 型号： | SC185HULTRT |
| 厂商： | Semtech |
| 文件页数： | 13/18页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC 1.5V 4A 16MLPQ |
| 标准包装： | 1 |
| 类型： | 降压（降压） |
| 输出类型： | 固定 |
| 输出数： | 1 |
| 输出电压： | 1.5V |
| 输入电压： | 2.9 V ~ 5.5 V |
| PWM 型： | 电压模式 |
| 频率 - 开关： | 1.5MHz |
| 电流 - 输出： | 4A |
| 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： | 16-UFQFN 裸露焊盘 |
| 包装： | 标准包装 |
| 供应商设备封装： | 16-MLPQ-UT（3x3） |
| 其它名称： | SC185HULDKR |
SC185
Applications Information
Detailed Description
The SC185 is a synchronous step-down Pulse Width
Modulated (PWM), DC-DC converter utilizing a 1.5MHz
fixed-frequency voltage mode architecture. The device is
designed to operate in fixed-frequency PWM mode and
has the option to enter power save mode (PSAVE) at light
loads to maximize efficiency. The switching frequency is
chosen to minimize the size of the external inductor and
capacitors while maintaining high efficiency.
Operation
During normal operation, the PMOS MOSFET is activated
on each rising edge of the internal oscillator. The period
is set by the onboard oscillator when in PWM mode. The
frequency being much lower than the PWM mode
frequency.
If the output load current increases enough to cause
V OUT to decrease below the PSAVE exit threshold (V OUT -
4%), the device automatically exits PSAVE and operates
in continuous PWM mode. Note that the PSAVE high
and low threshold levels are both set at or above V OUT to
minimize undershoot when the SC185 exits PSAVE. Figure
1 illustrates the transitions from PWM mode to PSAVE
mode and back to PWM mode.
device has an internal synchronous NMOS rectifier and
does not require a Schottky diode on the LX pin. The
device operates as a buck converter in PWM mode with
a fixed frequency of 1.5MHz at medium to high loads. At
light loads, depending on the MODE pin configuration, the
part will either enter PSAVE mode to maximize efficiency
or stay in forced PWM mode.
Load
Demand
( I OUT )
V
V OUT +2.5%
V OUT
OFF
Power Save Mode Operation
Connect the MODE pin to ground to enable the PSAVE
mode. When the load current decreases below the PSAVE
4%
V OUT -2%
BURST
threshold, PWM switching stops and the device automati-
cally enters PSAVE mode. This threshold varies depending
on the input voltage and output voltage setting, optimiz-
V LX
PSAVE
EXIT
ing efficiency for all possible load currents - whether in
PWM or PSAVE mode. While in PSAVE mode, output voltage
regulation is controlled by a series of bursts in switching.
During a burst, the inductor current is limited to a peak
PWM Mode at
Medium/High
Load
PSAVE Mode at
Light Load
Time
PWM Mode at
Medium/High
Load
?
?
?
?
value which controls the on-time of the PMOS switch. After
reaching this peak, the PMOS switch is disabled and the
inductor current is forced to near 0mA. Switching bursts
continue until the output voltage climbs to V OUT +2% or
until the PSAVE current limit is reached. Switching is then
stopped to eliminate switching losses, enhancing overall
efficiency. Switching resumes when the output voltage
reaches the lower threshold of V OUT and continues until the
upper threshold again is reached. Note that the output
voltage is regulated hysterically while in PSAVE mode
between V OUT and V OUT + 2%. The period and duty cycle
while in PSAVE mode are solely determined by V IN and V OUT
until PWM mode resumes. This can result in the switching
Figure 1 — Transitions between PWM and PSAVE
Modes
Protection Features
The SC185 provides the following protection features:
Current Limit
Over-Voltage Protection
Soft-Start Operation
Thermal Shutdown
? 2010 Semtech Corp.
13
www.semtech.com
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相关代理商/技术参数 |
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| SC185JEVB | 制造商:SEMTECH 功能描述:Evaluation Board For 4 A Synchronous Step-Down Regulator |
| SC185JULTRT | 功能描述:IC REG BUCK SYNC 1.8V 4A 16MLPQ RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 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 |
| SC185LEVB | 制造商:SEMTECH 功能描述:Evaluation Board For 4 A Synchronous Step-Down Regulator |
| SC185LULTRT | 功能描述:IC REG BUCK SYNC 2.5V 4A 16MLPQ RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 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 |
| SC185QEVB | 制造商:SEMTECH 功能描述:Evaluation Board For 4 A Synchronous Step-Down Regulator |
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