参数资料
| 型号： | LA5744-HK-E |
| 厂商： | ON Semiconductor |
| 文件页数： | 4/5页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 1A TO220-5 |
| 标准包装： | 50 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 可调至 1.23V |
| 输入电压： | 4.5 V ~ 28 V |
| PWM 型： | 电压模式 |
| 频率 - 开关： | 300kHz |
| 电流 - 输出： | 1A |
| 同步整流器： | 无 |
| 工作温度： | -30°C ~ 125°C |
| 安装类型： | 通孔 |
| 封装/外壳： | TO-220-5 成形引线 |
| 包装： | 管件 |
| 供应商设备封装： | 220-5HK |
LA5744
Protection Circuit Functional Descriptions
1. Overcurrent protection function
The overcurrent protection function detects, on a cycle-by-cycle basis, the output transistor current and turns off that
output transistor current if it exceeds 3.1A.
Limit current
Inductor current
SWOUT voltage
2. Short circuit protection function
This IC prevents the current from increasing when the outputs are shorted by setting the switching frequency to 30kHz
if the VOS pin voltage falls below 0.8V.
Note 3 : If the soft start function is not used, the IC will start up with the overcurrent protection function operating. At this
time, the switching frequency will be cut in half. This means that the switching frequency will be 15kHz at
startup.
Note 4 : Since the switching frequency becomes 30kHz when the VOS pin voltage falls under 0.8V, the current capacity is
reduced. If a load is applied with the VOS pin voltage over 0.8V, the inductance value operates at 22 μ H. If a load
is to be applied when this voltage is under 0.8V, the inductance value must be increased.
Description of Functional Settings
1. Calculation equation to set the output voltage
This IC controls the switching output so that the VOS pin voltage becomes 1.23V (typ).
The equation to set the output voltage is as follows :
VO = 1+
R2
R1
× 1.23V(typ)
The VOS pin has the inrush current of 1 μ A (typ). Therefore, the error becomes larger when R1 and R2 resistance
values are large.
2. Startup Delay Function
The output voltage rises when the internal voltage reaches 0.4V (typical). Until that point, a capacitor is charged from
an internal 10 μ A (typical) constant-current supply. The startup delay time can be calculated as shown below
Example : Assume a 1 μ F capacitor is used.
1 μ F × 0.4
10 μ A
Td =
C × V
i
= = 40 ms
No.A0717-4/5
相关PDF资料 |
PDF描述 |
|---|---|
| LA5744MP-DL-E | IC REG BUCK ADJ SMP5 |
| LA5744TP-TL-E | IC REG BUCK ADJ TP5HFA |
| LA5756-MDB-E | IC REG BUCK ADJ TO220-5 |
| LA5757TP-TL-E | IC REG BUCK ADJ TP5HFA |
| LA5759-MDB-E | IC REG BUCK ADJ TO220-5 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LA5744MP | 制造商:SANYO 制造商全称:Sanyo Semicon Device 功能描述:Monolithic Linear IC Separately-Excited Step-Down Switching Regulator (Variable Type) |
| LA5744MP-DL-E | 功能描述:直流/直流开关调节器 SWITCHING REGULATOR RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| LA5744MP-E | 功能描述:直流/直流开关调节器 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| LA5744TP | 制造商:SANYO 制造商全称:Sanyo Semicon Device 功能描述:Monolithic Linear IC Separately-Excited Step-Down Switching Regulator (Variable Type) |
| LA5744TP-FA-E | 功能描述:直流/直流开关调节器 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
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