- 您现在的位置：买卖IC网 > PDF目录14807 > LT3509IDE#PBF (Linear Technology)IC REG BUCK ADJ 0.7A DL 14DFN PDF资料下载
参数资料
| 型号： | LT3509IDE#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 10/24页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 0.7A DL 14DFN |
| 标准包装： | 91 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 2 |
| 输出电压： | 0.8 V ~ 35.3 V |
| 输入电压： | 3.6 V ~ 36 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 260kHz ~ 2.15MHz |
| 电流 - 输出： | 700mA |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 14-WFDFN 裸露焊盘 |
| 包装： | 管件 |
| 供应商设备封装： | 14-DFN-EP（4x3） |
LT3509
APPLICATIONS INFORMATION
External Synchronization
The external synchronization provides a trigger to the
internal oscillator. As such, it can only raise the frequency
above the free-run value. To allow for device and
component tolerances, the free run frequency should be
set to at least 12% lower than the lowest supplied external
synchronization reference. The oscillator and hence the
switching frequency can then pushed up from 12% above
the free-run frequency, set by the selected R T . For example,
if the minimum external clock is 300kHz, the R T should
be chosen for 264kHz.
The SYNC input has a threshold of 1.0V nominal so it is
compatible with most logic levels. The duty cycle is not
critical provided the high or low pulse width is at least
80ns.
Design Procedure
Before starting detailed design a number of key design
parameters should be established as these may affect
design decisions and component choices along the way.
One of the main things to determine apart from the desired
output voltages is the input voltage range. Both the normal
operating range and the extreme conditions of surges
and/or dips or brown-outs need to be known. Then the
operating frequency should be considered and if there
are particular requirements to avoid interference. If there
are very speci?c frequencies that need to be avoided then
external synchronization may be needed. This could also be
desirable if multiple switchers are used as low frequency
beating between similar devices can be undesirable. For
ef?cient operation this converter requires a boost supply so
that the base of the output transistor can be pumped above
the input voltage during the switch on time. Depending
on the input and output voltages the boost supply can be
provided by the input voltage, one of the regulated outputs
or an independent supply such as an LDO.
Input Voltage Range
Firstly, the LT3509 imposes some hard limits due to the
undervoltage lock-out and the overvoltage protection. A
given application will also have a reduced, normal operating
range over which maximum ef?ciency and lowest ripple
are obtained. This usually requires that the device is
operating at a ?xed frequency without skipping pulses.
There may also be zones above and below the normal
range where regulation is maintained but ef?ciency and
ripple may be compromised. At the low end, insuf?cient
input voltage will cause loss of regulation and increased
ripple—this is the dropout range. At the high end if the
duty cycle becomes too low this will cause pulse skipping
and excessive ripple. This is the pulse-skip region. Both
situations also lead to higher noise at frequencies other than
the chosen switching frequency. Occasional excursions
into pulse-skip mode, during surges for example, may be
tolerable. Pulse skipping will also occur at light loads even
within the normal operating range but ripple is usually not
degraded because at light load the output capacitor can
hold the voltage steady between pulses.
For input voltages greater than 30V, there are restrictions
on the inductor value. See the Inductor Selection section
for details.
To ensure the regulator is operating in continuous mode
it is necessary to calculate the duty cycle for the required
output voltage over the full input voltage range. This must
then be compared with minimum and maximum practical
duty cycles.
3509fc
10
相关PDF资料 |
PDF描述 |
|---|---|
| MAX6420UK43+T | IC MPU/RESET CIRC 4.30V SOT23-5 |
| RCM31DCAD-S189 | CONN EDGECARD 62POS R/A .156 SLD |
| LTC1879EGN#PBF | IC REG BUCK SYNC ADJ 1.2A 16SSOP |
| MAX6420UK45+T | IC MPU/RESET CIRC 4.50V SOT23-5 |
| LTC3417AIDHC-2#PBF | IC REG BUCK SYNC ADJ DL 16DFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3509IDE-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual 36V, 700mA Step-Down Regulator |
| LT3509IMSE#PBF | 功能描述:IC REG BUCK ADJ 0.7A DL 16MSOP 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:2,500 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V，1.5V，1.8V，2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘 |
| LT3509IMSE#PBF | 制造商:Linear Technology 功能描述:DC-DC CONVERTER BUCK 2.2MHZ 制造商:Linear Technology 功能描述:DC-DC CONVERTER, BUCK, 2.2MHZ, MSOP-16 |
| LT3509IMSE#TRPBF | 功能描述:IC REG BUCK ADJ 0.7A DL 16MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 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:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
| LT3509IMSE-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual 36V, 700mA Step-Down Regulator |
发布紧急采购，3分钟左右您将得到回复。