- 您现在的位置：买卖IC网 > PDF目录15304 > LT3844EFE#TRPBF (Linear Technology)IC REG CTRLR BST INV PWM 16TSSOP PDF资料下载
参数资料
| 型号： | LT3844EFE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 15/24页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BST INV PWM 16TSSOP |
| 标准包装： | 2,500 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 330kHz |
| 占空比： | 95% |
| 电源电压： | 4 V ~ 60 V |
| 降压： | 是 |
| 升压： | 是 |
| 回扫： | 无 |
| 反相： | 是 |
| 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： | 16-TSSOP（0.173"，4.40mm）裸露焊盘 |
| 包装： | 带卷 (TR) |
LT3844
APPLICATIONS INFORMATION
V SUPPLY(ON) is the input voltage at which the undervoltage
lockout is disabled and the supply turns on.
the C SS pin voltage enters its active region is approximated
by the following formula:
Example: Select R B = 49.9kΩ, V SUPPLY(ON) = 14.5V (based
on a 15V minimum input voltage)
t FAULT =
C SS ? 0 . 65 V
50 μ A
R A = 49 . 9 k ? ?
– 1 ?
? 14 .5 V
? 1 . 35 V
?
?
Oscillator SYNC
I SHDN = IN
C SS =
= 486.1k (499k resistor is selected)
If low supply current in standby mode is required, select
a higher value of R B .
The supply turn off voltage is 9% below turn on. In the
example the V SUPPLY(OFF) would be 13.2V.
If additional hysteresis is desired for the enable function,
an external positive feedback resistor can be used from
the LT3844 regulator output.
The shutdown function can be disabled by connecting the
SHDN pin to the V IN through a large value pull-up resistor.
This pin contains a low impedance clamp at 6V, so the SHDN
pin will sink current from the pull-up resistor(R PU ):
V – 6 V
R PU
Because this arrangement will clamp the SHDN pin to the
6V, it will violate the 5V absolute maximum voltage rating of
the pin. This is permitted, however, as long as the absolute
maximum input current rating of 1mA is not exceeded.
Input SHDN pin currents of <100μA are recommended:
a 1M or greater pull-up resistor is typically used for this
con?guration.
Soft-Start
The desired soft-start time (t SS ) is programmed via the
C SS capacitor as follows:
2 μ A ? t SS
1 . 231 V
The amount of time in which the power supply can withstand
a V IN , V CC or V SHDN UVLO fault condition (t FAULT ) before
The oscillator can be synchronized to an external clock.
Set the R SET resistor at least 10% below the desired sync
frequency.
It is recommended that the SYNC pin be driven with a
square wave that has amplitude greater than 2V, pulse
width greater than 1ms and rise time less than 500ns. The
rising edge of the sync wave form triggers the discharge
of the internal oscillator capacitor.
Ef?ciency Considerations
The ef?ciency of a switching regulator is equal to the output
power divided by the input power times 100%. Express
percent ef?ciency as:
% Ef?ciency = 100% - (L1 + L2 + L3 + ...)
where L1, L2, etc. are individual loss terms as a percent-
age of input power.
Although all dissipative elements in the circuit produce
losses, four main contributors usually account for most
of the losses in LT3844 circuits:
1. LT3844 V IN and V CC current loss
2. I 2 R conduction losses
3. MOSFET transition loss
4. Schottky diode conduction loss
1. The V IN and V CC currents are the sum of the quiescent
currents of the LT3844 and the MOSFET drive currents.
The quiescent currents are in the LT3844 Electrical Char-
acteristics table. The MOSFET drive current is a result
of charging the gate capacitance of the power MOSFET
each cycle with a packet of charge, Q G . Q G is found in
the MOSFET data sheet. The average charging current is
calculated as Q G ? f SW . The power loss term due to these
currents can be reduced by backdriving V CC with a lower
voltage than V IN such as V OUT .
3844fb
15
相关PDF资料 |
PDF描述 |
|---|---|
| IMC1210EBR12J | INDUCTOR WW 120NH 5% 1210 |
| VE-J2X-EY-F3 | CONVERTER MOD DC/DC 5.2V 50W |
| LTC3833IFE#PBF | IC REG CTRLR BUCK PWM CM 20TSSOP |
| GBM43DCCS | CONN EDGECARD 86POS R/A .156 SLD |
| LT3825EFE#TRPBF | IC REG CTRLR FLYBK ISO 16-TSSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3844IFE | 制造商:Linear Technology 功能描述:DC DC Cntrlr Single-OUT Step Down 4V to 60V Input 16-Pin TSSOP EP |
| LT3844IFE#PBF | 功能描述:IC REG CTRLR BST INV PWM 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) |
| LT3844IFE#TRPBF | 功能描述:IC REG CTRLR BST INV PWM 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: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 |
| LT3844IFEPBF | 制造商:Linear Technology 功能描述:DC-DC Controller Step-Down 4-60V TSSOP16 |
| LT3844IFE-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:High Voltage, Current Mode Switching Regulator Controller with Programmable Operating Frequency |
发布紧急采购，3分钟左右您将得到回复。