参数资料
| 型号： | LT3431IFE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 21/28页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 3A 16TSSOP |
| 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： | 1.2 V ~ 48 V |
| 输入电压： | 5.5 V ~ 60 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 500kHz |
| 电流 - 输出： | 3A |
| 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： | 16-TSSOP（0.173"，4.40mm）裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 16-TSSOP-EP |
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LT3431
APPLICATIO S I FOR ATIO
A detailed theoretical basis for estimating internal power
dissipation is given in the Thermal Calculations section.
This will allow a first pass check of whether an application’s
maximum input voltage requirement is suitable for the
LT3431. Be aware that these calculations are for DC input
voltages and that input voltage transients as high as 60V
are possible if the resulting increase in internal power
dissipation is of insufficient time duration to raise die
temperature significantly. For the FE package, this means
high voltage transients on the order of hundreds of milli-
seconds are possible. If LT3431 thermal calculations
show power dissipation is not suitable for the given
tion, the theoretical analysis considers only first order
non-ideal component behavior. For these reasons, it is
important that a final stability check is made with produc-
tion layout and components.
The LT3431 uses current mode control. This alleviates
many of the phase shift problems associated with the
inductor. The basic regulator loop is shown in Figure 10.
The LT3431 can be considered as two g m blocks, the error
amplifier and the power stage.
LT3431
application, the LT3430 is a recommended alternative
CURRENT MODE
POWER STAGE
SW
OUTPUT
since it is identical to the LT3431 but runs cooler at
200kHz.
g m = 2mho
ERROR
AMPLIFIER
FB
C FB
R1
CERAMIC
Switch minimum on time is the other factor that may limit
the maximum operational input voltage for the LT3431 if
R O
200k
g m =
2000 μ mho
1.22V
R LOAD
+
ESR
ESL
pulse-skipping behavior is not allowed. For the LT3431,
pulse-skipping may occur for V IN /(V OUT + V F ) ratios > 4.
(V F = Schottky diode D1 forward voltage drop, Figure 5.)
If the LT3430 is used, the ratio increases to 10. Pulse-
GND
V C
R C
C C
C F
R2
C1
TANTALUM
C1
skipping is the regulator’s way of missing switch pulses to
maintain output voltage regulation. Although an increase
in output ripple voltage can occur during pulse-skipping,
a ceramic output capacitor can be used to keep ripple
voltage to a minimum (see output ripple voltage compari-
son for tantalum vs ceramic output capacitors, Figure 3).
FREQUENCY COMPENSATION
Before starting on the theoretical analysis of frequency
response, the following should be remembered—the worse
the board layout, the more difficult the circuit will be to
stabilize. This is true of almost all high frequency analog
circuits, read the Layout Considerations section first.
Common layout errors that appear as stability problems
are distant placement of input decoupling capacitor and/
or catch diode, and connecting the V C compensation to a
ground track carrying significant switch current. In addi-
3431 F10
Figure 10. Model for Loop Response
Figure 11 shows the overall loop response. At the V C pin,
the frequency compensation components used are:
R C = 3.3k, C C = 0.022 μ F and C F = 220pF. The output
capacitor used is a 100 μ F, 10V tantalum capacitor with
typical ESR of 100m ? .
The ESR of the tantalum output capacitor provides a
useful zero in the loop frequency response for maintain-
ing stability.
This ESR, however, contributes significantly to the ripple
voltage at the output (see Output Ripple Voltage in the
Applications Information section). It is possible to reduce
capacitor size and output ripple voltage by replacing the
sn3431 3431fs
21
相关PDF资料 |
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| LT3433IFE#TRPBF | IC REG BUCK BST ADJ 0.5A 16TSSOP |
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相关代理商/技术参数 |
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| LT3433 | 制造商:LINER 制造商全称:Linear Technology 功能描述:High Voltage Step-Up/Step-Down DC/DC Converter |
| LT3433_1 | 制造商:LINER 制造商全称:Linear Technology 功能描述:High Voltage Step-Up/Step-Down DC/DC Converter |
| LT3433EFE | 功能描述:IC REG BUCK BST ADJ 0.5A 16TSSOP RoHS:否 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 |
| LT3433EFE#PBF | 功能描述:IC REG BUCK BST ADJ 0.5A 16TSSOP 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:250 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V 输入电压:2.05 V ~ 6 V PWM 型:电压模式 频率 - 开关:2MHz 电流 - 输出:500mA 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:6-UFDFN 包装:带卷 (TR) 供应商设备封装:6-SON（1.45x1） 产品目录页面:1032 (CN2011-ZH PDF) 其它名称:296-25628-2 |
| LT3433EFE#TR | 功能描述:IC REG BUCK BST ADJ 0.5A 16TSSOP RoHS:否 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 |
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