- 您现在的位置：买卖IC网 > PDF目录44993 > LTC3812IFE-5 (LINEAR TECHNOLOGY CORP) 1 A SWITCHING CONTROLLER, PDSO16 PDF资料下载
参数资料
| 型号： | LTC3812IFE-5 |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 1 A SWITCHING CONTROLLER, PDSO16 |
| 封装： | 4.40 MM, PLASTIC, TSSOP-16 |
| 文件页数： | 9/32页 |
| 文件大小： | 425K |
| 代理商： | LTC3812IFE-5 |
第1页第2页第3页第4页第5页第6页第7页第8页当前第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
LTC3812-5
17
38125fb
MINIMUM OFF-TIME AND DROPOUT OPERATION
The minimum off-time tOFF(MIN) is the smallest amount of
time that the LTC3812-5 is capable of turning on the bot-
tom MOSFET, tripping the current comparator and turning
the MOSFET back off. This time is generally about 250ns.
The minimum off-time limit imposes a maximum duty
cycle of tON/(tON + tOFF(MIN)). If the maximum duty cycle
is reached, due to a dropping input voltage for example,
then the output will drop out of regulation. The minimum
input voltage to avoid dropout is:
VIN(MIN) = VOUT
tON + tOFF(MIN)
tON
A plot of maximum duty cycle vs frequency is shown in
Figure 8.
INDUCTOR SELECTION
Given the desired input and output voltages, the induc-
tor value and operating frequency determine the ripple
current:
IL =
VOUT
f L
1
VOUT
VIN
Lower ripple current reduces core losses in the inductor,
ESR losses in the output capacitors and output voltage
ripple. Highest efciency operation is obtained at low
frequency with small ripple current. However, achieving
this requires a large inductor. There is a tradeoff between
component size, efciency and operating frequency.
A reasonable starting point is to choose a ripple current
that is about 40% of IOUT(MAX). The largest ripple current
occurs at the highest VIN. To guarantee that ripple current
does not exceed a specied maximum, the inductance
should be chosen according to:
L
=
VOUT
f IL(MAX)
1
VOUT
VIN(MAX)
Once the value for L is known, the type of inductor must
be selected. High efciency converters generally cannot
afford the core loss found in low cost powdered iron cores,
forcing the use of more expensive ferrite, molypermalloy
or Kool Mμ cores. A variety of inductors designed for
high current, low voltage applications are available from
manufacturers such as Sumida, Panasonic, Coiltronics,
Coilcraft and Toko.
SCHOTTKY DIODE D1 SELECTION
The Schottky diode D1 shown in the front page schematic
conducts during the dead time between the conduction of
the power MOSFET switches. It is intended to prevent the
body diode of the bottom MOSFET from turning on and
storing charge during the dead time, which can cause a
modest (about 1%) efciency loss. The diode can be rated
for about one half to one fth of the full load current since
APPLICATIONS INFORMATION
Figure 8. Maximum Switching Frequency vs Duty Cycle
2.0
1.5
1.0
0.5
0
0.25
0.50
0.75
38125 F08
1.0
DROPOUT
REGION
DUTY CYCLE (VOUT/VIN)
SWITCHING
FREQUENCY
(MHz)
相关PDF资料 |
PDF描述 |
|---|---|
| LTC3831IGN | SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO16 |
| LTC3833IUDC#PBF | SWITCHING CONTROLLER, 2000 kHz SWITCHING FREQ-MAX, PQCC20 |
| LTC3833EFE#TRPBF | SWITCHING CONTROLLER, 2000 kHz SWITCHING FREQ-MAX, PDSO20 |
| LTC3833EUDC#TRPBF | SWITCHING CONTROLLER, 2000 kHz SWITCHING FREQ-MAX, PQCC20 |
| LTC3833EUDC#PBF | SWITCHING CONTROLLER, 2000 kHz SWITCHING FREQ-MAX, PQCC20 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3812IFE-5#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 16TSSOP 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) |
| LTC3812IFE-5#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 16TSSOP 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) |
| LTC3813EG#PBF | 功能描述:IC REG CTRLR BST PWM CM 28-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 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 |
| LTC3813EG#TRPBF | 功能描述:IC REG CTRLR BST PWM CM 28-SSOP 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) |
| LTC3813IG#PBF | 功能描述:IC REG CTRLR BST PWM CM 28-SSOP 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: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。