参数资料
| 型号： | SC121ULTRT |
| 厂商： | Semtech |
| 文件页数： | 19/23页 |
| 文件大小： | 0K |
| 描述： | IC REG BOOST SYNC 3.3V/ADJ 6MLPD |
| 标准包装： | 1 |
| 类型： | 升压（升压） |
| 输出类型： | 两者兼有 |
| 输出数： | 1 |
| 输出电压： | 3.3V，1.8 V ~ 5 V |
| 输入电压： | 0.7 V ~ 4.5 V |
| 频率 - 开关： | 1.2MHz |
| 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-MLPD-UT |
| 包装： | 标准包装 |
| 供应商设备封装： | 6-MLPD-UT（1.5x2.0） |
| 其它名称： | SC121ULTRTDKR |
SC121
Applications Information (continued)
Note that this is a negative quantity, since V OUT > V IN and
0 < D < 1. For a constant load in steady-state, the inductor
current must satisfy Δ I L-on + Δ I L-off = 0. Substituting the two
expressions and solving for D, obtain D = 1 – V IN /V OUT .
Using this expression, and the positive valued expression
Δ I L = Δ I L-on for current ripple amplitude, obtain expanded
Manufacturer/
Part #
Murata
LQM31PN4R7M00
Coilcraft
XFL2006-472
Value
(μH)
4.7
4.7
DCR
(Ω)
0.3
0.7
Rated
Current
(mA)
700
500
Tolerance
(%)
20
20
Dimensions
LxWxH
(mm)
3.2 x 1.6 x 0.95
2 x 2 x 0.6
expression for I L-max and I L-min .
Capacitor Selection
I L
max,min
V OUT I OUT
V IN
T V IN
2 L V OUT
V OUT V IN
Input and output capacitors must be chosen carefully to
ensure that they are of the correct value and rating. The
From this result, obtain an alternative expression for Δ I L .
output capacitor requires a minimum capacitance value
of 10μF at the programmed output voltage to ensure sta-
I L
I L
max
I L
min
T
L
V IN
V OUT
V OUT
V IN
bility over the full operating range. This must be consid-
ered when choosing small package size capacitors as the
DC bias must be included in their derating to ensure this
The inductor selection should consider the n-channel FET
current limit for the expected range of input voltage and
output load current. The largest I L-avg will occur at the
expected smallest V IN and largest I OUT . Determine the
largest expected Δ I L . Then for the largest expected I L-avg ,
ensure that the n-channel FET current limit is not exceed.
That is, for the minimum n-channel FET current limit,
worst case inductor tolerance, highest expected output
current, and lowest expected V IN , ensure that
I L-max = I L-avg + Δ I L /2 < I LIM(N) .
Many of these equations include the parameter η , effi -
ciency. Effi ciency varies with V IN , I OUT , and temperature.
Estimate η using the plots provided in this datasheet, or
from experimental data, at the operating condition of
interest.
required value. For example, a 10μF 0805 capacitor may
provide suffi cient capacitance at low output voltages but
may be too low at higher output voltages. Therefore, a
higher capacitance value may be required to provide the
minimum of 10μF at these higher output voltages.
Low ESR capacitors such as X5R or X7R type ceramic
capacitors are recommended for input bypassing and
output filtering. Low-ESR tantalum capacitors are not
recommended due to possible reduction in capacitance
seen at the switching frequency of the SC121. Ceramic
capacitors of type Y5V are not recommended as their tem-
perature coeffi cients make them unsuitable for this appli-
cation. The following table lists recommended capacitors.
For smaller values and smaller packages, it may be neces-
sary to use multiples devices in parallel.
Any chosen inductor should have low DCR compared to
the R DS-ON of the FET switches to maintain efficiency,
though for DCR << R DS-ON , further reduction in DCR will
provide diminishing benefit. The inductor I SAT value should
exceed the expected I L-max . The inductor self-resonant fre-
quency should exceed 5×f osc . Any inductor with these
properties should provide satisfactory performance.
L = 4.7μH should perform well for most applications.
The following table lists the manufacturers of recom-
Manufacturer/
Part Number
Murata
GRM21BR60J226ME39B
Murata
GRM31CR71A226KE15L
Murata
GRM185R60G475ME15
TDK
C2012X5R1A226M
Taiyo Yuden
JMK212BJ226MG-T
Value
(μF)
22
22
4.7
22
22
Rated Volt-
age (VDC)
6.3
10
4
10
20
Type
X5R
X7R
X5R
X5R
X5R
Case
Size
0805
1206
0603
0805
0805
Case
Height
(mm)
1.25
1.6
0.5
0.85
1.25
mended inductor options. The specification values shown
are simplified approximations or averages of many device
parameters under various test conditions. See manufac-
turers’ documentation for full performance data.
19
相关PDF资料 |
PDF描述 |
|---|---|
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SC122 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Low Voltage Synchronous Boost Converter |
| SC1225-1001F | 制造商:Lista International Corp 功能描述:SC Cabinet Combination |
| SC122EVB | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Low Voltage Synchronous Boost Converter |
| SC122ULTRT | 功能描述:IC REG BST SYNC 3.3V 95MA 6MLPD 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 |
| SC-1230 | 制造商:Nidec Copal 功能描述:SWIT ROTARY 16 SLOT SHAFT PC PINS 0.1A 5VDC - Bulk |
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