参数资料
| 型号： | SC194BMLTRT |
| 厂商： | Semtech |
| 文件页数： | 8/17页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 1A 10MLP |
| 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： | 可调 |
| 输入电压： | 2.7 V ~ 5.5 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 1MHz |
| 电流 - 输出： | 1A |
| 同步整流器： | 无 |
| 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-MLP（3x3） |
| 产品目录页面： | 1357 (CN2011-ZH PDF) |
| 其它名称： | SC194BMLDKR |
SC194B
POWER MANAGEMENT
Applications Information (Cont.)
In PSAVE mode V OUT is driven from a lower level to an
upper level by a switching burst. Once the upper level has
been reached the switching is stopped and the quiescent
current is reduced. V OUT falls from the upper to lower levels
in this low current state as the load current discharges
the output capacitor. The burst-to-off period in PSAVE will
decrease as the load current reduces.
The PSAVE switching burst frequency is controlled so
that the inductor current ripple is similar to that in PWM
mode.
The SC194B automatically detects when to exit PSAVE
mode by monitoring V OUT . For the SC194B to exit PSAVE
mode, the load must be increased, causing V OUT to
decrease until the power save exit threshold is reached.
PSAVE levels are set high to minimize the undershoot
100% Duty Cycle Operation
The 100% duty cycle mode may be selected by connecting
the MODE pin high. This will allow the SC194B to maintain
output regulation under low input voltage/high output
voltage conditions.
In 100% duty cycle operation, as the input supply drops
toward the output voltage, the PMOS on-time increases
linearly above the maximum value in ? xed-frequency
operation until the PMOS is active continuously. Once
the PMOS is switched on continuously, the output voltage
tracks the input voltage minus the voltage drop across
the PMOS power device and inductor according to the
following relationship:
V OUT V IN I OUT (R DSP R IND )
when exiting PSAVE. The lower PSAVE comparator level
is set +0.7% above V OUT , and the upper comparator level
at +1.5% above V OUT , with the exit threshold at -2% below
V OUT .
If PSAVE operation is required then a 22 μ F output
capacitor must be used.
where,
V OUT
V IN
I OUT
R DSP
R IND
= Output voltage
= Input voltage
= Output current
= PMOS switch ON resistance
= Series resistance of the inductor
Power Save Operation
Higher Load
Inductor Selection
The SC194B is designed for use with a 4.7 μ H inductor.
The magnitude of the inductor current ripple is dependent
1.5%
BURST
OFF
Applied
on the inductor value and can be determined by the
following equation:
0.7%
V OUT
-2%
PSAVE Mode at Light Load
PWM Mode at Medium/
High Load
I L
V OUT
L f osc
1
V OUT
V IN
This equation demonstrates the relationship between
Inductor Current
input voltage, output voltage, and inductor ripple
current.
The inductor should have a low DCR to minimize the
0A
Time
conduction losses and maximize ef ? ciency. As a
minimum requirement, the DC current rating of the
inductor should be equal to the maximum load current
plus half of the inductor current ripple as shown by the
following equation:
I L(PK)
I O UT(MAX)
I L
2
? 2006 Semtech Corp.
8
www.semtech.com
相关PDF资料 |
PDF描述 |
|---|---|
| SC195ULTRT | IC REG BUCK SYNC ADJ 0.5A 8MLPQ |
| SC196AMLTRT | IC REG BUCK SYNC 1.5A 10MLP |
| SC196ULTRT | IC REG BUCK SYNC ADJ 1.5A 10MLPD |
| SC198AMLTRT | IC REG BUCK SYNC PROG .8A 20MLPQ |
| SC198MLTRT | IC REG BUCK SYNC PROG .6A 20MLPQ |
相关代理商/技术参数 |
参数描述 |
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| SC195 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:3.5MHz, 500mA Synchronous Step Down DC-DC Regulator |
| SC195_10 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:3.5MHz, 500mA Synchronous Step Down DC-DC Regulator |
| SC1959 | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Mini size of Discrete semiconductor elements |
| SC195EVB | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:3.5MHz, 500mA Synchronous Step Down DC-DC Regulator |
| SC195UL.TRT | 制造商:SEMTECH 功能描述:I.C. |
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