- 您现在的位置：买卖IC网 > PDF目录1823 > LT1941EFE#TRPBF (Linear Technology)IC REG MULTI CONFIG TRPL 28TSSOP PDF资料下载
参数资料
| 型号： | LT1941EFE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 11/24页 |
| 文件大小： | 0K |
| 描述： | IC REG MULTI CONFIG TRPL 28TSSOP |
| 标准包装： | 2,000 |
| 类型： | 降压（降压），升压（升压），反相，Sepic |
| 输出类型： | 可调式 |
| 输出数： | 3 |
| 输出电压： | 1.25 V ~ 40 V |
| 输入电压： | 3.5 V ~ 25 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 1.1MHz |
| 电流 - 输出： | 3A |
| 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： | 28-SOIC（0.173"，4.40mm 宽）裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 28-TSSOP 裸露焊盘 |
LT1941
APPLICATIONS INFORMATION
your load is lower than the maximum load current, then
you can relax the value of the inductor and operate with
higher ripple current. This allows you to use a physically
smaller inductor or one with a lower DCR resulting in
higher ef?ciency. Be aware that if the inductance differs
from the simple rule above, then the maximum load current
will depend on input voltage. In addition, low inductance
may result in discontinuous mode operation, which further
reduces maximum load current. For details of maximum
output current and discontinuous mode operation, see
Linear Technology’s Application Note AN44. Finally, for
duty cycles greater than 50% (V OUT /V IN > 0.5), a minimum
inductance is required to avoid subharmonic oscillations.
See AN19.
The current in the inductor is a triangle wave with an average
value equal to the load current. The peak switch current
is equal to the output current plus half the peak-to-peak
inductor ripple current. The LT1941 limits its switch cur-
rent in order to protect itself and the system from overload
faults. Therefore, the maximum output current that the
LT1941 will deliver depends on the switch current limit,
the inductor value and the input and output voltages.
When the switch is off, the potential across the inductor
is the output voltage plus the catch diode drop. This gives
the peak-to-peak ripple current in the inductor:
ΔI L = (1 – DC)(V OUT + V F )/(L ? f)
where f is the switching frequency of the LT1941 and L
is the value of the inductor. The peak inductor and switch
current is:
I SWPK = I LPK = I OUT + ΔI L /2
To maintain output regulation, this peak current must be
less than the LT1941’s switch current limit I LIM . For SW1,
I LIM is at least 3A at low duty cycles and decreases linearly
to 2.4A at DC = 0.8. For SW2, I LIM is at least 2A for at low
duty cycles and decreases linearly to 1.6A at DC = 0.8.
The maximum output current is a function of the chosen
inductor value:
I OUT(MAX) = I LIM – ΔI L /2
= 3 ? (1 – 0.25 ? DC) – ΔI L /2 for SW1
= 2 ? (1 – 0.25 ? DC) – ΔI L /2 for SW2
Choosing an inductor value so that the ripple current is
small will allow a maximum output current near the switch
current limit.
One approach to choosing the inductor is to start with the
simple rule given above, look at the available inductors
and choose one to meet cost or space goals. Then use
these equations to check that the LT1941 will be able to
deliver the required output current. Note again that these
equations assume that the inductor current is continu-
ous. Discontinuous operation occurs when I OUT is less
than ΔI L /2.
Output Capacitor Selection
For 5V and 3.3V outputs, a 10μF, 6.3V ceramic capacitor
(X5R or X7R) at the output results in very low output volt-
age ripple and good transient response. For lower voltages,
10μF is adequate for ripple requirements but increasing
C OUT will improve transient performance. Other types and
values will also work; the following discusses tradeoffs in
output ripple and transient performance.
The output capacitor ?lters the inductor current to generate
an output with low voltage ripple. It also stores energy in
order to satisfy transient loads and stabilize the LT1941’s
control loop. Because the LT1941 operates at a high
frequency, minimal output capacitance is necessary. In
addition, the control loop operates well with or without
the presence of output capacitor series resistance (ESR).
Ceramic capacitors, which achieve very low output ripple
and small circuit size, are therefore an option.
1941fb
11
相关PDF资料 |
PDF描述 |
|---|---|
| LT1942EUF#TRPBF | IC REG SW QUAD TFT LCD 24-QFN |
| LT1943EFE#TRPBF | IC REG SW QUAD TFT LCD 28-TSSOP |
| LT1944-1EMS#TR | IC REG BST ADJ 0.1A/175MA 10MSOP |
| LT1945IMS#TRPBF | IC REG MULTI CONFIG ADJ 10MSOP |
| LT1946EMS8E#TRPBF | IC REG BOOST 1.5A 8MSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1942 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Quad DCDC Converter for Triple Outputs TFT Supply Plus LED Driver |
| LT1942EUF | 制造商:Linear Technology 功能描述:Conv DC-DC Quad Inv/Step Up 2.6V to 16V 24-Pin QFN EP |
| LT1942EUF#PBF | 功能描述:IC REG SW QUAD TFT LCD 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 标准包装:43 系列:- 应用:控制器，Intel VR11 输入电压:5 V ~ 12 V 输出数:1 输出电压:0.5 V ~ 1.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-VFQFN 裸露焊盘 供应商设备封装:48-QFN（7x7） 包装:管件 |
| LT1942EUF#TRPBF | 功能描述:IC REG SW QUAD TFT LCD 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 标准包装:43 系列:- 应用:控制器，Intel VR11 输入电压:5 V ~ 12 V 输出数:1 输出电压:0.5 V ~ 1.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-VFQFN 裸露焊盘 供应商设备封装:48-QFN（7x7） 包装:管件 |
| LT1942EUFPBF | 制造商:Linear Technology 功能描述:Conv DC-DC Quad Inv/Step-Up 16V QFN24EP |
发布紧急采购，3分钟左右您将得到回复。