参数资料
| 型号： | SC4501MLTRT |
| 厂商： | Semtech |
| 文件页数： | 8/21页 |
| 文件大小： | 0K |
| 描述： | IC REG BOOST ADJ 2A 10MLPD |
| 标准包装： | 1 |
| 类型： | 升压（升压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 可调至 32V |
| 输入电压： | 1.4 V ~ 16 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 1.5MHz |
| 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： | 10-VFDFN 裸露焊盘 |
| 包装： | 标准包装 |
| 供应商设备封装： | 10-MLPD（3x3） |
| 其它名称： | SC4501MLDKR |
SC4501
POWER MANAGEMENT
R 1 = R 2 ? ? 1 ?
? 1 . 242 V
?
Operation
The SC4501 is a programmable constant-frequency peak
current-mode step-up switching regulator with an
integrated 2A power transistor. Referring to the block
diagrams in Figures 2 and 3, the power transistor is
switched on at the trailing edge of the clock. Switch
current is sensed with an integrated sense resistor. The
sensed current is summed with the slope-compensating
ramp before compared to the output of the error
amplifier EA. The PWM comparator trip point determines
the switch turn-on pulse width. The current-limit
Application Information
Setting the Output Voltage
An external resistive divider R 1 and R 2 with its center tap
tied to the FB pin (Figure 4) sets the output voltage.
V OUT
(1)
VOUT
comparator ILIM turns off the power switch when the
switch current exceeds the 2.8A current-limit threshold.
ILIM therefore provides cycle-by-cycle current limit.
Current-limit is not affected by slope compensation
because the current comparator ILIM is not in the PWM
signal path.
R1
40nA
R2
2
SC4501
FB
Current-mode switching regulators utilize a dual-loop
feedback control system. In the SC4501 the amplifier
output COMP controls the peak inductor current. This is
the inner current loop. The double reactive poles of the
output LC filter are reduced to a single real pole by the
Figure 4. The Output Voltage is set with a Resistive Divider
The input bias current of the error amplifier will introduce
an error of:
inner current loop, easing loop compensation. Fast
transient response can be obtained with a simple Type-2
compensation network. In the outer loop, the error
Δ V OUT
V OUT
=
40nA ( R 1 // R 2 ) 100
1 . 242 V
%
(2)
amplifier regulates the output voltage.
The switching frequency of the SC4501 can be programmed
up to 2MHz with an external resistor from the ROSC pin
The percentage error of a V OUT = 5V converter with R 1 =
100K Ω and R 2 = 301K Ω is
to the ground. For converters requiring extreme duty
cycles, the operating frequency can be lowered to
maintain the necessary minimum on time or the minimum
Δ V OUT
V OUT
=
40nA ( 100K // 301K ) 100
1 . 242 V
= 0 . 24 %
off time.
Operating Frequency and Efficiency
The SC4501 requires a minimum input of 1.4V to operate.
A voltage higher than 1.1V at the shutdown pin enables
the internal linear regulator REG in the SC4501. After V REG
becomes valid, the soft-start capacitor is charged with a
1.5 μ A current source. A PNP transistor clamps the output
of the error amplifier as the soft-start capacitor voltage
rises. Since the COMP voltage controls the peak inductor
current, the inductor current is ramped gradually during
soft-start, preventing high input start-up current. Under
fault conditions (V IN <1.4V or over temperature) or when
the shutdown pin is pulled below 1.1V, the soft-start
capacitor is discharged to ground. Pulling the shutdown
pin below 0.1V reduces the total supply current to 10 μ A.
Switching frequency of SC4501 is set with an external
resistor from the ROSC pin to the ground. A graph showing
the relationship between R OSC and switching frequency is
given in the “Typical Characteristics”.
High frequency operation reduces the size of passive
components but switching losses are higher. The efficiencies
of 5V to 12V converters operating at 700KHz, 1.35MHz
and 2MHz are shown in Figure 1(b). The peak efficiency
of the SC4501 appears to decrease 0.5% for every
100KHz increase in frequency.
2011
? 2005 Semtech Corp.
8
www.semtech.com
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| SC4508AMLTRT | IC REG CTRLR BST INV PWM 12-MLPQ |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SC4501MSETRT | 功能描述:IC REG BOOST ADJ 2A 8MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 产品培训模块:MIC23xxx HyperLight Load™ Regulators 标准包装:5,000 系列:HyperLight Load® 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.8V 输入电压:2.7 V ~ 5.5 V PWM 型:混合物 频率 - 开关:4MHz 电流 - 输出:2A 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:8-VFDFN 裸露焊盘，8-MLF? 包装:带卷 (TR) 供应商设备封装:8-MLF?（2x2） 产品目录页面:1094 (CN2011-ZH PDF) 其它名称:576-3303-2 |
| SC4501STDEVB | 制造商:Semtech Corporation 功能描述:EVALUATION BOARD 制造商:SEMTECH 功能描述:Eval Board for SC4501 Step-Up Switching Regulator |
| SC4502 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:1.4Amp, 2MHz Step-Up Switching Regulator with Soft-Start |
| SC4502EVB | 制造商:SEMTECH 功能描述:Evaluation Board for SC4502 Series Step-up Switching Regulator |
| SC4502H | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:1.4Amp, 2MHz Step-Up Switching Regulator with Soft-Start |
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