参数资料
| 型号： | SC4524SETRT |
| 厂商： | Semtech |
| 文件页数： | 9/21页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK 2A 8SOIC |
| 标准包装： | 1 |
| 类型： | 降压（降压） |
| 输出数： | 1 |
| 输入电压： | 2.8 V ~ 30 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 1.4MHz |
| 电流 - 输出： | 2A |
| 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： | 8-SOIC（0.154"，3.90mm 宽） |
| 包装： | 标准包装 |
| 供应商设备封装： | 8-SOIC-EP |
| 产品目录页面： | 1358 (CN2011-ZH PDF) |
| 其它名称： | SC4524SEDKR |
SC4524
POWER MANAGEMENT
Applications Information
Setting the Output Voltage
The regulator output voltage is set with an external
resistive divider (Figure 4) with its center tap tied to the
FB pin.
The switching frequency is limited by the minimum
controllable on time at low duty cycles. For V IN > 20V,
setting switching frequency below 500kHz makes
converter output short circuit operation more robust.
These will be described in more details later.
Minimum On Time Consideration
The operating duty cycle of a non-synchronous step-down
switching regulator in continuous-conduction mode (CCM)
is given by
Figure 4. V OUT is set with a Resistive Divider
' =
9 + 9
9 + 9 - 9
(2)
5 = 5 9
-
(1)
where V CESAT is the switch saturation voltage and V D is
voltage drop across the rectifying diode.
The percentage error due the input bias current of the
error amplifier is
Duty cycle decreases with increasing
9
9
ratio. In peak
D 9 - Q$ ? ? 5 ?? 5
9
9
=
= - .
9
= .
Example: Determine the output voltage error of a
9 = 9 converter with 5 = N W .
From (1),
5 = N W ? - = N W
D 9 - Q$ ? ? N ?? N
9 9
current-mode control, the PWM modulating ramp is the
sensed current ramp of the power switch. This current
ramp is absent unless the switch is turned on. The
intersection of this ramp with the output of the voltage
feedback error amplifier determines the switch pulse
width. The propagation delay time required to
immediately turn off the switch after it is turned on is
the minimum controllable switch on time (T ON(MIN) ). Closed-
9
loop measurement of the SC4524 with low ratios
This error is at least an order of magnitude lower than
the ratio tolerance resulting from the use of 1% resistors
in the divider string.
Setting the Switching Frequency
The switching frequency of the SC4524 is set with an
external resistor from the ROSC pin to ground. A graph
of switching frequency against R OSC is shown in ?Typical
Performance Characteristics?. The switching frequency
is programmable up to 1.5MHz.
Figure 5. Variation of Minimum On Time with
Ambient Temperature.
? 2006 Semtech Corp.
9
www.semtech.com
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SC4525A | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:28V 3A Step-Down Switching Regulator |
| SC4525AEVB | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:28V 3A Step-Down Switching Regulator |
| SC4525ASETRT | 功能描述:IC REG BUCK 3A 8SOIC 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:20 系列:SIMPLE SWITCHER® 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:12V 输入电压:4 V ~ 60 V PWM 型:电压模式 频率 - 开关:52kHz 电流 - 输出:1A 同步整流器:无 工作温度:-40°C ~ 125°C 安装类型:通孔 封装/外壳:16-DIP（0.300"，7.62mm） 包装:管件 供应商设备封装:16-DIP 其它名称:*LM2575HVN-12LM2575HVN-12 |
| SC4525C | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:28V 3A Step-Down Switching Regulator Thermal Shutdown |
| SC4525CSETRT | 功能描述:IC REG BUCK ADJ 3A 8SOIC 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 |
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