参数资料
| 型号： | SC195ULTRT |
| 厂商： | Semtech |
| 文件页数： | 14/20页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 0.5A 8MLPQ |
| 特色产品： | SC195 Buck Regulator |
| 标准包装： | 1 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.8 V ~ 3.3 V |
| 输入电压： | 2.9 V ~ 5.5 V |
| PWM 型： | 电压模式 |
| 频率 - 开关： | 3.5MHz |
| 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： | 8-MLPQ |
| 包装： | 标准包装 |
| 供应商设备封装： | 8-MLPQ-UT（1.5x1.5） |
| 产品目录页面： | 1357 (CN2011-ZH PDF) |
| 其它名称： | SC195ULDKR |
SC195
Applications Information (continued)
Load
Demand
( I OUT )
V OUT +2.5%
V OUT
V OUT -2%
OFF
BURST
disabled. Switching does not resume until V OUT has fallen
below the regulation voltage by 2%.
Current Limit
The SC195 switching stage is protected by a current limit
function. If the output load exceeds the PMOS current
limit for 32 consecutive switching cycles, the device enters
fold-back current limit mode and the output current is
limited to approximately 150mA. Under these conditions,
V LX
PSAVE
EXIT
PWM Mode at PSAVE Mode at PWM Mode at
Medium/High Light Load Medium/High
Load Load
Time
Figure 2 — Transitions Between PWM and PSAVE Modes
Protection Features
The SC195 provides the following protection features:
? Soft-Start Operation
? Over-Voltage Protection
? Current Limit
? Thermal Shutdown
? Under-Voltage Lockout
Soft-Start
The soft-start sequence is activated after a transition from
an all zeros CTL code to a non-zero CTL code enables the
device. At start-up, the PMOS current limit is stepped
through four levels: 25%, 40%, 60%, and 100%. Each step
is maintained for 60μs following an internal reference start
up of 20μs, resulting in a total nominal start-up period of
260μs. If V OUT reaches 90% of the target within the first 2
steps, the device continues in PSAVE mode at the end of
soft-start; otherwise, it goes into PWM mode. Note the
V OUT ripple in PSAVE mode can be larger than the ripple in
PWM mode.
Over-Voltage Protection
Over-voltage protection ensures the output voltage does
not rise to a level that could damage its load. When V OUT
exceeds the regulation voltage by 15%, the PWM drive is
the output voltage will be the product of I FB-LIM and the load
resistance. The load must fall below I FB-LIM for the device to
exit fold-back current limit mode. This function makes the
device capable of sustaining an indefinite short circuit on
its output under fault conditions.
Thermal Shutdown
The SC195 has a thermal shutdown feature to protect the
device if the junction temperature exceeds 160°C. During
thermal shutdown, the PMOS and NMOS switches are
both disabled, tri-stating the LX output. When the junc-
tion temperature drops by the hysteresis value (20°C), the
device goes through the soft-start process and resumes
normal operation.
Under-Voltage Lockout
Under-Voltage Lockout (UVLO) activates when the supply
voltage drops below the UVLO threshold. This prevents
the device from entering an ambiguous state in which
regulation cannot be maintained. Hysteresis of approxi-
mately 200mV is included to prevent chattering near the
threshold.
Inductor Selection
The SC195 is designed to operate with a 1μH inductor
between the LX pin and the OUT pin. Other values may
lead to instability, malfunction, or out-of-specification
performance. The specified current levels for PSAVE entry,
PSAVE exit, and current limit are dependent on the induc-
tor value.
The SC195 converter has internal loop compensation. The
compensation is designed to work with a specific single-
14
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SC196 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:1.5A Synchronous Buck Converter with Integrated Power Devices |
| SC1968 | 制造商:MITSUBISHI 制造商全称:Mitsubishi Electric Semiconductor 功能描述:NPN EPITAXIAL PLANAR TYPE |
| SC196A | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:1.5A Synchronous Buck Converter with Integrated Power Devices |
| SC196A_08 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:1.5A Synchronous Buck Converter with Integrated Power Devices |
| SC196AEVB | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:1.5A Synchronous Buck Converter with Integrated Power Devices |
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