参数资料
| 型号： | SC4524BSETRT |
| 厂商： | Semtech |
| 文件页数： | 11/18页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK 2A 8SOIC |
| 产品培训模块： | Power Supplies 101 |
| 标准包装： | 1 |
| 类型： | 降压（降压） |
| 输出数： | 1 |
| 输入电压： | 3 V ~ 18 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 300kHz ~ 1.3MHz |
| 电流 - 输出： | 2A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm Width）裸露焊盘 |
| 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： | SC4524BSEDKR |
L =
O D
20 % ? I O ? F SW
I RMS _ CIN = I O ? D ? ( ? D )
SC4524B
V o
V c
=
D V = D I L ? ? ? ESR +
?
8 ? F SW ? C O ? ?
ApplicationsInformation(Cont.)
Minimum Off Time Limitation
? ?
?
The input O capacitance must also be high enough to keep
input ripple voltage within specification. This is important
G PWM
be able 4 to R reach V O its ? set ? ? value in continuous-conduction
R = 6 ?
?
? . 0 V ?
Inductor Selection V D
R D 4 I L = = R 6 ? ? O O D ? ? ?
? . 0 F SW ? L ?
V
inductance. ( V O V + O V + D ) V ? D ( ? D )
V IN 20 V % D ? ? I O V ? CESAT
L D = =
efficiency, _ cost and size. ? Re-arranging Equation (3) and
assuming = 35% inductor ripple current, the inductor is
L D V O = = D O I L ? ? ? ESR +
( V + V D ) ? ( ? D ) ?
35 V % ? ? I O ? F SW 8 ? F SW ? C O ? ?
R 4 = R 6 ?
? ?
L based on the nominal input voltage. Always verify
converter operation V at the input voltage extremes.
V O I + D
C D IN = > V + V O ? V
IN 4 ? D V IN ? F CESAT
The peak current limit of SC4524B power transistor is at
SW
SC4524B is 2.6A ? ? ? minus one F half C of ? ? the inductor ripple
( V O + ? V D ) ? ( 8 ? D ) SW ? O ?
D V O = D I L ESR +
current. I L =
L C = > O
The input capacitor O should be chosen to handle the RMS
? V
R 7 =
A C =
R C 4 IN = > R 6 ? ?
? ?
V O I O
4 ? ? D . V 0 IN V ? F SW ??
? V ? A C =
A where 20 V ? IN log ? ? the allowable input ripple voltage.
? FB ? ?
C = ?
? V G O CA + R V S D 2 π F C C O
V O ?
Multi-layer V ceramic ? capacitors, which have very low ESR
A C = ? 20 ? log ? ?
(a few m W ) and can easily handle high RMS ripple current, . 0 ?
are the ideal ? choice . for 0 input 2 π filtering. A ? single 4.7μF . 3 ? 7
? ? ? R = 5
28 ? 6
?
? 80 ? 0
22 ? 0
3
X5R ceramic ( capacitor ( is adequate for 500kHz or higher
F SW ? L
for 200kHz to 500kHz switching frequency. For high
0 20 ?
R 7 =
A voltage 28 applications, a ? small ceramic ? ? ( μF or 2.2μF) can be
log ? ? 3
= 22 . 3 k V ?
C = 0 . 20 ? ? 0 ?
C 8 =
( V O G CA R ) S ( 2 ? π D C C O V O ?
2 π ? 6 ? 0 ? 22 . ? 0 3
A C = ? 20 ? log ? ?
?
?
? = 5
Output Capacitor 6 . ? 0 ? 3 2 π ? 80 ? 0 3 ? 22 ? 0 ? 6 3 . 3 ? V o
C 8 =
2 π I RMS _ CIN ? 0 I O 3 ? ? 22 D . ? ( ? 0 D 3 )
? 600 =
= 2 pF =
V c
R expressed as ? 3 = 22 . 3 k
7 =
= 0 . 28 ? 0 PWM ?
V o G ( + s R ESR C O )
? G PWM
( D + V s O / = ω D ) I ( L ? + ? ? ESR ω + n Q + s 2 / ω n 2 ) ? ?
V c
s /
8 ? 3 F SW 0 ? . C 45 O nF
C 5 =
=
3 ? ?
where C O is the output capacitance.
V ?
G A PWM = = ? ≈ 20 ? log ? ? , 3
R R 7 =
? ω p ≈ 3 R C = ? 2 FB pF ? ?
ω Z =
,
,
C 8
Since the inductor ? R 22 ripple C C current ? D I L increases as D
2 G 600 S 0 . ? 0 R ESR C O
? CA I O S 2 π F
O V
4 ? D V IN ? F SW
decreases > (Equation (3)), the output ripple voltage is C 5 =
therefore the ? highest when V is at its maximum.
0
R A V 7 o C = ? 20 ? log PWM ( + s R ESR C O ) IN ?
. 0 ?
= g m
G ? ? 3 3 ? 6 ? ? = 5
s / ω p ? ) ( + s / ω n Q + s 2 / ω n 2 )
3 . 3 ? C =
V A c 0μF + to 47μF X5R ceramic capacitor is found adequate
28 ? 6 . ? 0 2 π ? 80 ? 0 ? 22 ? 0
C for = output filtering in most applications. Ripple current
in the π 0 Z R 20 R 7 capacitor is not a concern because the
2 F output
G inductor current of a buck ≈ converter directly = feeds C , ,
= 0 . 28 CA ? 0 S
C resulting in very low ripple current. Avoid using Z5U O
G ? R R C O R ESR C O
2 π F P R 7
C and = Y5V A C ceramic capacitors 3 for 0 output filtering because
= . 45 nF
2 20 ? 6 ? 0 3 ? 22 . ? 0
0 π types of capacitors have high temperature and high
C 8 = = 2 pF
C Freewheeling Diode
5 =
Use of Schottky ( barrier diodes as freewheeling rectifiers
= =
( 2 π F / R ω p
easing high-side current sensing in the SC4524B. These
The PWM latch in Figure 2 is reset every cycle by the
clock. The clock also turns off the power transistor to
refresh the bootstrap capacitor. This minimum off time
limits the attainable duty cycle of the regulator at a given
switching frequency. The measured minimum off time is
00ns typically. If the required duty cycle is higher than
the attainable maximum, then the output voltage will not
mode.
D =
V IN + V D ? V CESAT
The inductor ripple current for a non-synchronous step-
down converter in continuous-conduction mode is
( V V + V ) ? ( ? D)
(3)
where F SW is the switching frequency and L is the
+ F SW
An inductor ripple current between 20% to 50% of the
maximum load current gives a good compromise among
F SW ? L
given by
? (4)
? O ?
? . 0 V ?
If the input voltage varies over a wide range, then choose
I RMS _ CIN = I O ? D ? ( ? D )
D
? ?
least 2.6A. The maximum deliverable load current for the
?
F SW ? L
Input Decoupling Capacitor
I D
( V + V O ) ? ( ? D )
IN
ripple current of a buck converter. This value is given by
I RMS _ CIN = I O ? D ? ( ? D) (5)
in reducing the conductive EMI from the regulator. The
input capacitance can be estimated from
D is ?
D =
IN + V D V CESAT
? 3 3 ? 6
5 . 9
? ? FB
=
? I ? F 5 = = 0 . 45 nF 20 %
placed L in parallel with a low ESR electrolytic capacitor to
C satisfy both the 3 ESR O and SW bulk capacitance requirements.
. 0 ?
?
The output 5 . 9 ripple voltage D V O of a buck converter can be
0 20
p (7)
2 π ? 6 ? 0 ? 22 . ? 0
C
O O
A C
20
( 8
5
5 . 9
7 = ,
R PWM ≈ ? 3 = 22 . 3 k ω p , ω Z
8
5
7 =
R these
m
voltage coefficients.
2 π ? 600 ? 0 3 ? 22 . ? 0 3
2 π F Z R 7
o
V + ) + / ω Q + s 2 / ω 2 ) 8
C reduces s diode ( reverse n recovery n input current spikes,
P 7
(6) C 5 =
C 8 =
I L = D
switching frequency applications, and 0μF is adequate C 5 =
D V = D I ? ? ESR +
?
?
?
G PWM ≈
R
G CA ? R S
,
ω p ≈
R C O
,
ω Z =
R ESR C O
,
相关PDF资料 |
PDF描述 |
|---|---|
| SC4524CSETRT | IC REG BUCK ADJ 2A 8SOIC |
| SC4524DSETRT | IC REG BUCK ADJ 2A 8SOIC |
| SC4524SETRT | IC REG BUCK 2A 8SOIC |
| SC4525ASETRT | IC REG BUCK 3A 8SOIC |
| SC4525CSETRT | IC REG BUCK ADJ 3A 8SOIC |
相关代理商/技术参数 |
参数描述 |
|---|---|
| SC4524C | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:28V 2A Step-Down Switching Regulator Wide input range: 3V to 28V |
| SC4524CSETRT | 功能描述:IC REG BUCK ADJ 2A 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 |
| SC4524CSETRT-CUT TAPE | 制造商:SEMTECH 功能描述:SC4524 Series 28 V 2 A 2 MHz Step-Down Switching Regulator - SOIC-8 |
| SC4524D | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:18V 2A Step-Down Switching Regulator 2A Output Current |
| SC4524DSETRT | 功能描述:IC REG BUCK ADJ 2A 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 |
发布紧急采购，3分钟左右您将得到回复。