- 您现在的位置：买卖IC网 > PDF目录192316 > SC4540ULTRT SWITCHING REGULATOR, 920 kHz SWITCHING FREQ-MAX, DSO8 PDF资料下载
参数资料
| 型号： | SC4540ULTRT |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING REGULATOR, 920 kHz SWITCHING FREQ-MAX, DSO8 |
| 封装： | 2 X 2 MM, ROHS COMPLIANT, MLPD-8 |
| 文件页数： | 3/15页 |
| 文件大小： | 281K |
| 代理商： | SC4540ULTRT |
11
Applications Information (continued)
SC4540
must withstand high voltage for an extended period of
time.
Soft-Start
The soft-start mode reduces in-rush current by utilizing
the external compensation network. As the error amplifier
slowly charges the COMP node voltage, the duty cycle of
the boost switch ramps from 0% to its final value when in
regulation. The gradual increase of the duty cycle slowly
charges the output capacitor and limits in-rush current
during start up. Soft-start is implemented only when the
power is cycled on the part.
Thermal Shutdown
A thermal shutdown mode is included for protection in
the event the junction temperature exceeds 155°C. In
thermal shutdown, the on-chip power switch is disabled.
Switching and sinking resumes when the temperature
drops by 20°C.
Current Limit
The power switch of the boost converter is protected by
an internal current limit function. The switch is opened
when the current exceeds the maximum switch current
value.
Inductor Selection
The inductor value should be within the range of 22μH to
68μH. The DCR needs to be considered when selecting
the inductor to ensure optimum efficiency. The largest
inductor package that can be accommodated in the circuit
area should be used since the DCR generally decreases
with increasing package size.
The saturation current of the inductor should be much
higher than the peak current of the internal boost switch
to ensure that the inductor never enters saturation during
normal operation of the part. The equation to calculate
the peak inductor current is:
2
I
L
IN
L(Peak)
where
osc
IN
L
f
L
D
V
I
OUT
IN
V
1
D
IN
OUT
IN
V
I
V
I
D is the duty cycle for continuous operation. Efficiency (η)
can be approximated by using the curves provided in the
Typical Characteristics section. Table 1 lists inductors that
have been proven to work with SC4540.
Table 1 — Recommended Inductors
Part Number
Value
(μH)
DCR
(Ω)
Rated
Current (A)
Toler-
ance
Dimensions
(L x W x H)
(mm)
Coilcraft
LPS6235
56
0.28
1.1
±20%
6.2 x 6.2 x 3.5
Coilcraft
LPS4018-223ML
22
0.360
0.70
±20%
3.9 x 3.9 x 1.7
Capacitor Selection
The input capacitor should be at least 2.2μF. A larger
capacitor will reduce the voltage ripple on the input. The
output capacitor values can range from 0.22μF to 1μF. The
compensation capacitor value should be 47nF. Capacitors
of X5R type material or better can be used for any of the
capacitors. See Table 2 for recommended capacitors.
Table 2 — Recommended Capacitors
Part Number
Value
(μF)
Rated
Voltage (V)
Type
Case Size
Input Capacitor
Murata
GRM219R61E225KA12
2.2
25
X5R
0805
Output Capacitor
Murata
GRM21BR71H105KA12L
1.0
50
X7R
0805
Compensation Capacitor
Taiyo Yuden
EMK105BJ473KV-F
0.047
16
X7R
0402
相关PDF资料 |
PDF描述 |
|---|---|
| SC52-11SEKWA | 7 SEG NUMERIC DISPLAY, SUPER BRIGHT ORANGE, 13.2 mm |
| SCAN182245ASSCX | |
| SCAN182245ASSC | |
| SCAN182245AMTDX | |
| SCAN182374ASSC | |
相关代理商/技术参数 |
参数描述 |
|---|---|
| SC4541SKTRT | 功能描述:IC LED DRVR BACKLIGHT SOT23-6 RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:60 系列:- 恒定电流:- 恒定电压:- 拓扑:线性（LDO），PWM，升压（升压） 输出数:8 内部驱动器:是 类型 - 主要:背光 类型 - 次要:RGB，白色 LED 频率:500kHz ~ 1.5MHz 电源电压:4.75 V ~ 26 V 输出电压:45V 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:* 工作温度:-40°C ~ 85°C |
| SC4541ULTRT | 制造商:Semtech Corporation 功能描述:SINGLE WIRE BACKLIGHT DRIVER |
| SC454MLTRT | 制造商:Semtech Corporation 功能描述:PWM Controller 32-Pin MLP T/R 制造商:Semtech Corporation 功能描述:SINGLE PHASE PWR SUPPLY CONTLR |
| SC4560 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:相机闪光灯控制IC |
| SC457 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Single-Phase Single Chip Vcore Power Supply |
发布紧急采购，3分钟左右您将得到回复。