- 您现在的位置：买卖IC网 > PDF目录14142 > LTC1701ES5#TR (Linear Technology)IC REG BUCK ADJ 0.5A TSOT23-5 PDF资料下载
参数资料
| 型号： | LTC1701ES5#TR |
| 厂商： | Linear Technology |
| 文件页数： | 7/12页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 0.5A TSOT23-5 |
| 标准包装： | 2,500 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1.25 V ~ 5 V |
| 输入电压： | 2.5 V ~ 5.5 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 1MHz |
| 电流 - 输出： | 500mA |
| 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： | SOT-23-5 细型，TSOT-23-5 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | TSOT-23-5 |
LTC1701/LTC1701B
APPLICATIO S I FOR ATIO
Input Capacitor (C IN ) Selection
In continuous mode, the input current of the converter is
a square wave with a duty cycle of approximately V OUT /
V IN . To prevent large voltage transients, a low equivalent
series resistance (ESR) input capacitor sized for the maxi-
mum RMS current must be used. The maximum RMS
capacitor current is given by:
When the capacitance of C OUT is made too small, the
output ripple at low frequencies will be large enough to trip
the I TH comparator. This causes Burst Mode operation to
be activated when the LTC1701 would normally be in
continuous mode operation. The effect can be improved at
higher frequencies with lower inductor values.
In surface mount applications, multiple capacitors may
I RMS ≈ I MAX
V OUT ( V IN ? V OUT
V IN
)
have to be paralleled to meet the capacitance, ESR or RMS
current handling requirement of the application. Alumi-
num electrolyte and dry tantulum capacitors are both
available in surface mount configurations. In the case of
where the maximum average output current I MAX equals
the peak current (1 Amp) minus half the peak-to-peak
ripple current, I MAX = 1 – ? I L /2.
This formula has a maximum at V IN = 2V OUT , where I RMS
= I OUT /2. This simple worst-case is commonly used to
design because even significant deviations do not offer
much relief. Note that capacitor manufacturer’s ripple
current ratings are often based on only 2000 hours life-
time. This makes it advisable to further derate the capaci-
tor, or choose a capacitor rated at a higher temperature
than required. Several capacitors may also be paralleled to
meet the size or height requirements of the design. An
additional 0.1 μ F to 1 μ F ceramic capacitor is also recom-
mended on V IN for high frequency decoupling.
Output Capacitor (C OUT ) Selection
The selection of C OUT is driven by the required ESR.
Typically, once the ESR requirement is satisfied, the
capacitance is adequate for filtering. The output ripple
( ? V OUT ) is determined by:
tantalum, it is critical that the capacitors are surge tested
for use in switching power supplies. An excellent choice is
the AVX TPS, AVX TPSV and KEMET T510 series of
surface mount tantalums, avalable in case heights ranging
from 2mm to 4mm. Other capacitor types include Nichicon
PL series, Sanyo POSCAP and Panasonic SP.
Ceramic Capacitors
Higher value, lower cost ceramic capacitors are now
becoming available in smaller case sizes. These are tempt-
ing for switching regulator use because of their very low
ESR. Unfortunately, the ESR is so low that it can cause
loop stability problems. Solid tantalum capacitor ESR
generates a loop “zero” at 5kHz to 50kHz that is instrumen-
tal in giving acceptable loop phase margin. Ceramic ca-
pacitors remain capacitive to beyond 300kHz and usually
resonate with their ESL before ESR becomes effective.
Also, ceramic caps are prone to temperature effects which
requires the designer to check loop stability over the
operating temperature range.
For these reasons, most of the input and output capaci-
? V OUT L ? ESR +
≈ ? I
8 fC OUT ?
?
?
1 ?
?
tance should be composed of tantalum capacitors for
stability combined with about 0.1 μ F to 1 μ F of ceramic
capacitors for high frequency decoupling. Great care must
where f = operating frequency, C OUT = output capacitance
and ? I L = ripple current in the inductor. With ? I L = 0.4
I OUT(MAX) the output ripple will be less than 100mV with:
ESR COUT < 100m ?
Once the ESR requirements for C OUT have been met, the
RMS current rating generally far exceeds the I RIPPLE(P-P)
requirement.
be taken when using only ceramic input and output capaci-
tors. The OPTI-LOOP compensation allows transient re-
sponse to be optimized for all types of output capacitors,
including low ESR ceramics.
Setting the Output Voltage
The LTC1701 develops a 1.25V reference voltage between
the feedback pin, V FB , and the signal ground as shown in
7
相关PDF资料 |
PDF描述 |
|---|---|
| MAX6867UK18D5L+T | IC MPU SUPERVISOR SOT23-5 |
| LNC2H332MSEH | CAP ALUM 3300UF 500V 20% SCREW |
| VE-BNX-EX-F2 | CONVERTER MOD DC/DC 5.2V 75W |
| LNY2G682MSEG | CAP ALUM 6800UF 400V 20% SCREW |
| VE-BNX-EW-F2 | CONVERTER MOD DC/DC 5.2V 100W |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC1702ACGN | 功能描述:IC REG CTRLR BUCK PWM VM 24-SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC1702ACGN#PBF | 功能描述:IC REG CTRLR BUCK PWM VM 24-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC1702ACGN#TR | 功能描述:IC REG CTRLR BUCK PWM VM 24-SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC1702ACGN#TRPBF | 功能描述:IC REG CTRLR BUCK PWM VM 24-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC1702AIGN | 功能描述:IC REG CTRLR BUCK PWM VM 24-SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
发布紧急采购，3分钟左右您将得到回复。