参数资料
| 型号： | SC2446ITETRT |
| 厂商： | Semtech |
| 文件页数： | 23/38页 |
| 文件大小： | 0K |
| 描述： | IC SYNC STEP DOWN CTRLR 28-TSSOP |
| 标准包装： | 1 |
| 应用： | 控制器，DDR |
| 输入电压： | 4.7 V ~ 16 V |
| 输出数： | 2 |
| 输出电压： | 可调至 0.5V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-SOIC（0.173"，4.40mm 宽）裸露焊盘 |
| 供应商设备封装： | 28-TSSOP 裸露焊盘 |
| 包装： | 标准包装 |
| 产品目录页面： | 1358 (CN2011-ZH PDF) |
| 其它名称： | SC2446ITEDKR |
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SC2446
POWER MANAGEMENT
Application Information (Cont.)
s z 2 =
,
s p 2 =
C 2 C 3
C 2 + C 3
The transconductance error amplifier (in the SC2446)
has a gain g m of 260 μ A/V. The target of the compensation
design is to select the compensation network consisting
of C 2 , C 3 and R 2 , along with the feedback resistors R o1 ,
R o2 and the current sensing gain, such that the converter
output voltage is regulated with satisfactory dynamic
performance.
With the output voltage V o known, the feedback gain h
and the feedback resistor values are determined using
the equations given in the “Output Voltage Setting” section
1
R 2 C 2
and
1
R 2
The loop transfer function is then
.
h =
.
k =
I o
with
0 . 5
V o
For the rated output current I o , the current sensing gain
k is first estimated as
.
2 . 1
T(s)=G vc (s)C(s).
To simplify design, we assume that C 3 <<C 2 , R oesr <<R o,
selects S p1 =S z2 and specifies the loop crossover
frequency f c . It is noted that the crossover frequency
determines the converter dynamic bandwidth. With these
assumptions, the controller parameters are determined
as following.
From Figure 17, the transfer function from the voltage
error amplifier output v c to the converter output v o is
C 2 =
g m hkR o
2 π f c
,
: = G vc ( s ) = kR o
R 2 =
C 3 =
V o ( s )
V c ( s )
where, the single dominant pole is
1 +
1 +
s
s z 1
s
s p 1
.
and
R o C o
C 2
R oesr C o
R 2
,
K ,
s p 1 =
,
1
( R o + R oesr ) C o
and the zero due to the output capacitor ESR is
with a constant K.
For example, if V o =2.5V, I o =15A, f s =300kHz, C o =1.68mF,
R oesr =4.67m ? , one can calculate that
s z 1 =
1
R oesr C o
.
R o =
V o
I o
= 167 m ? ,
The dominant pole moves as output load varies.
The controller transfer function (from the converter
h =
0 .5
V o
= 0 . 2 ,
output v o to the voltage error amplifier output v c ) is
C ( s ) =
g m h
s ( C 2 + C 3 )
1 +
1 +
s
s z 2
s
s p 2
,
and
k =
I o
2 . 1
= 7 . 14 .
where
? 2004 Semtech Corp.
23
www.semtech.com
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SC2446ITSTRT | 制造商:Semtech Corporation 功能描述:Controller IC 制造商:Semtech Corporation 功能描述:SC Series 4.7 to 16 V 1 MHz Dual-Phase Synchronous Step-Down Controller TSSOP-28 |
| SC2447 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Dual-Phase, Single or Dual Output Synchronous Step-Down Controller |
| SC24-470-R | 功能描述:INDUCTOR SHIELD 47UH 150MA SMD RoHS:是 类别:电感器，线圈，扼流圈 >> 固定式 系列:SC24 标准包装:500 系列:1331 电感:1.2µH 电流:247mA 电流 - 饱和:247mA 电流 - 温升:- 类型:铁芯体 容差:±10% 屏蔽:屏蔽 DC 电阻(DCR):最大 730 毫欧 Q因子@频率:40 @ 7.9MHz 频率 - 自谐振:130MHz 材料 - 芯体:铁 封装/外壳:0.312" L x 0.115" W x 0.135" H（7.94mm x 2.92mm x 3.43mm） 安装类型:表面贴装 包装:带卷 (TR) 工作温度:-55°C ~ 105°C 频率 - 测试:7.9MHz |
| SC24-471-R | 功能描述:INDUCTOR SHIELD 470UH 50MA SMD RoHS:是 类别:电感器，线圈，扼流圈 >> 固定式 系列:SC24 标准包装:500 系列:1331 电感:1.2µH 电流:247mA 电流 - 饱和:247mA 电流 - 温升:- 类型:铁芯体 容差:±10% 屏蔽:屏蔽 DC 电阻(DCR):最大 730 毫欧 Q因子@频率:40 @ 7.9MHz 频率 - 自谐振:130MHz 材料 - 芯体:铁 封装/外壳:0.312" L x 0.115" W x 0.135" H（7.94mm x 2.92mm x 3.43mm） 安装类型:表面贴装 包装:带卷 (TR) 工作温度:-55°C ~ 105°C 频率 - 测试:7.9MHz |
| SC2447EVB | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Dual-Phase, Single or Dual Output Synchronous Step-Down Controller |
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