- 您现在的位置：买卖IC网 > PDF目录1832 > LTC3852EUDD#PBF (Linear Technology)IC REG CTRLR DOUBLER PWM 24-QFN PDF资料下载
参数资料
| 型号： | LTC3852EUDD#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 20/32页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR DOUBLER PWM 24-QFN |
| 标准包装： | 73 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 810kHz |
| 占空比： | 99% |
| 电源电压： | 2.7 V ~ 38 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 是 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 24-WFQFN 裸露焊盘 |
| 包装： | 管件 |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页当前第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页
LTC3852
APPLICATIONS INFORMATION
C OUT Selection
The selection of C OUT is primarily determined by the effec-
tive series resistance, ESR, to minimize voltage ripple. The
output ripple, D V OUT , in continuous mode is determined by:
where D I is the change in current from full load to zero load
(or minimum load) and D V is the allowed voltage devia-
tion (not including any droop due to ?nite capacitance).
The amount of capacitance needed is determined by the
Δ V OUT ? Δ I L ? ESR +
?
?
1 ?
8 fC OUT ? ?
maximum energy stored in the inductor. The capacitance
must be suf?cient to absorb the change in inductor
current when a high current to low current transition
L ( Δ I )
2 ( Δ V ) V OUT
C OUT >
R ESR ≤
wheref=operatingfrequency,C OUT =outputcapacitance
and D I L = ripple current in the inductor. The output ripple
is highest at maximum input voltage since D I L increases
with input voltage. Typically, once the ESR requirement
for C OUT has been met, the RMS current rating gener-
ally far exceeds the I RIPPLE(P-P) requirement. With D I L =
0.3I OUT(MAX) and allowing 2/3 of the ripple to be due to
ESR, the output ripple will be less than 50mV at maximum
V IN and:
C OUT Required ESR < 2.2R SENSE
1
8 fR SENSE
The ?rst condition relates to the ripple current into the ESR
of the output capacitance while the second term guarantees
that the output capacitance does not signi?cantly discharge
during the operating frequency period due to ripple current.
The choice of using smaller output capacitance increases
the ripple voltage due to the discharging term but can be
compensated for by using capacitors of very low ESR to
maintain the ripple voltage at or below 50mV. The I TH pin
OPTI-LOOP compensation components can be optimized
to provide stable, high performance transient response
regardless of the output capacitors selected.
The selection of output capacitors for applications with
large load current transients is primarily determined by the
voltage tolerance speci?cations of the load. The resistive
component of the capacitor, ESR, multiplied by the load
current change, plus any output voltage ripple must be
within the voltage tolerance of the load.
The required ESR due to a load current step is:
Δ V
Δ I
occurs. The opposite load current transition is generally
determined by the control loop OPTI-LOOP components,
so make sure not to over compensate and slow down
the response. The minimum capacitance to assure the
inductors’ energy is adequately absorbed is:
2
C OUT >
where D I is the change in load current.
Manufacturers such as Nichicon, United Chemi-Con and
Sanyo can be considered for high performance through-
hole capacitors. The OS-CON semiconductor electrolyte
capacitor available from Sanyo has the lowest (ESR)(size)
product of any aluminum electrolytic at a somewhat
higher price. An additional ceramic capacitor in parallel
with OS-CON capacitors is recommended to reduce the
inductance effects.
In surface mount applications, ESR, RMS current handling
and load step speci?cations may require multiple capacitors
in parallel. Aluminum electrolytic, dry tantalum and
special polymer capacitors are available in surface mount
packages. Special polymer surface mount capacitors offer
very low ESR but have much lower capacitive density per
unit volume than other capacitor types. These capacitors
offer a very cost-effective output capacitor solution and are
an ideal choice when combined with a controller having
high loop bandwidth. Tantalum capacitors offer the highest
capacitance density and are often used as output capacitors
for switching regulators having controlled soft-start.
Several excellent surge-tested choices are the AVX TPS,
AVX TPSV or the KEMET T510 series of surface mount
tantalums, available in case heights ranging from 1.5mm
to 4.1mm. Aluminum electrolytic capacitors can be used
in cost-driven applications, provided that consideration
3852f
20
相关PDF资料 |
PDF描述 |
|---|---|
| LTC3853EUJ#PBF | IC REG CTRLR BUCK PWM CM 40-QFN |
| LTC3854EMSE#PBF | IC REG CTRLR BUCK PWM CM 12-MSOP |
| LTC3855IUJ#PBF | IC REG CTRLR BUCK PWM CM 40-QFN |
| LTC3856IFE#TRPBF | IC REG CTRLR BUCK PWM CM 38TSSOP |
| LTC3858IUH#TRPBF | IC REG CTRLR BUCK PWM CM 32-QFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3852IUDD#PBF | 功能描述:IC REG CTRLR DOUBLER PWM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 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:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC3852IUDD#TRPBF | 功能描述:IC REG CTRLR DOUBLER PWM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 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:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC3853EUJ#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 40-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 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:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| LTC3853EUJ#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 40-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 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:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| LTC3853EUJPBF | 制造商:Linear Technology 功能描述:DC-DC Controller Triple Buck 24V QFN40 |
发布紧急采购，3分钟左右您将得到回复。