参数资料
| 型号： | SC4524ASETRT |
| 厂商： | Semtech |
| 文件页数： | 14/19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 ~ 28 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 ~ 105°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： | SC4524ASEDKR |
2 π ? 6 ? 0 ? 22 . ? 0 3
C 5 =
3
= 0 . 45 nF
SC4524A
C 8 =
2 π ? 600 ? 0 3 ? 22 . ? 0 3
= 2 pF
V o G PWM ( + s R ESR C O )
(3) Place the compensator zero, F Z , 2 between 0% and
V c ( + s / ω p ) ( + s / ω n Q + s / ω n )
F Z . R
(5) Then, the parameters of the compensation network R
G CA ? R S
G PWM ≈ , ω p ≈ , ω Z =
conduction loss P C , the switching loss P SW , and bootstrap
circuit P loss P BST, P can + P be SW estimated P as follows:
TOTAL =
+ P BST + Q
ApplicationsInformation(Cont.)
=
20% of the crossover frequency, F C .
(4) Use the compensator pole, F P , to cancel the ESR zero,
R C O
can be calculated by
Thermal Considerations
For the power transistor inside the SC4524A, the
,
ESR C O C
0 20
P SW =
? t S ? V IN ? I O ? F SW
P BST = D ? V BST ?
R 7 =
C 5 =
C 8 =
A C
g m
2 π F Z R 7
2 π F P R 7
P C = D ? V CESAT ? I O
2
I O
40
P Q = V IN ? 2 mA
( 0)
(20% of F = C ), ? ? ? 20 ? log P ? ? =600kHz. 2 π From Equation (9), the
? FB ? ?
and F G R V FB ? ? ?
place voltage compensator zero and pole at F Z = 6kHz
F C C O
V O ?
required compensator F C gain V at ? ? F C is
A C = ? 20 ? log ? ? ? CA ? S
Input Voltage
where g m =0.28mA/V is the EA gain of the SC4524A.
Example : Determine the voltage compensator for an
800kHz, 2V to 3.3V/2A converter with 22uF ceramic
output capacitor.
Choose a loop gain crossover frequency of 80kHz, and
A C
? G CA R S 2 π C O O
P ( ? D ) ? D ? I O D
where V BST = is the BST V supply voltage and t S is the equivalent
switching time of the NPN transistor (see Table 3).
P ~ . 3 ? I 2O ? R DC IND =
Table ( 3. . Typical ) switching time
Load Current
1A 2A
12V 12.5ns 15.3ns
24V 22ns 25ns
28V 25.3ns 28ns
A C = ? A C ? = log ? ? ? 20 ? log ? ? 3 ?
? = P C ? ? = + 5 . 9 dB + P BST + ? P addition, the quiescent current loss is
? P
P
In Q ? = 5 . 9 dB
? . 0 . 0 ?
? 28 ? 6 . ? 0 28 2 ? π 6 ? . ? ? 0 3 ? ? 3 22 2 TOTAL 6 80 3 . ? 3 0 3 ? SW ? 0 ? 6
? 0 ? ?
π
?
3 . 3 ?
22
Then the compensator parameters are P = D ? V
CESAT ? I O
0
0 20
R 7 = = 22 5 3 k
The total power loss of the SC4524A is therefore
R 7 =
= 22 . 3 k
0 . 28 ? 0 ? 3 3 = 0 . 45 nF
P SW =
? t S ? V IN ? I O ? F SW
2
C 5 = 3
C 5 =
= 0 . 45 nF
P TOTAL = P C + P SW + P BST + P Q ( 2)
I O
C 8 =
2 ? 0 π 3 ? 6 . ? 0 0 3 3 ? = 22 . pF ? 0 3 P
2
BST = D ? V BST ?
The temperature rise ? of the SC4524A P is Q the V product of the
P C = D ? V CESAT I O
40 = IN ? 2 mA
C 8 = G
= 2 pF
total power dissipation (Equation ( 2)) and q JA (36 o C/W),
2 π ? 600 ? 0 2 ? 22 . ? 0 3
V o PWM ( + s R ESR C O ) 3
which is the thermal impedance from junction to ambient
P D = ( ? D ) ? V D ? I O
=
( + s / ω p ) ( + s / ω n Q + s / ω n )
V c
for the SOIC-8 2 EDP package. F SW
P SW = ? t S ? V IN ? I O ?
G PWM ≈ ( + , s R ESR C O ω ) Z =
G PWM ≈ V o
ω p
,
,
G CA = ? R S parameters for various 2 P IND ESR 2 = C O ( applications ? R DC It is not recommended to operate the SC4524A above
I
Compensator typical . ~ . 3 ) ? I O
R C O
R
V c ( + s / ω p ) ( + s / ω n Q + s / ω n ) P BST = D ? V BST ? O
are listed in Table 4. A MathCAD program is also available 25 C junction temperature. In the applications with high
0
upon request for detailed calculation of the compensator input voltage and high output current, the switching
R 7 =
parameters.
frequency = may ? D need D to I O be reduced to meet the thermal
R
) ? V ?
P D
(
C requirement.
G PWM ≈ , ω p ≈ , ω Z = ,
2 π F Z R 7
C 5 = G ? R R C R
20
80 0 ?
5 . 9 P Q = V IN ? 2 mA ( )
20 C
0 . 28 ? 0 ? 3
2 π ? 6 ? 0 ? 22 . ? 0
2 π ? 600 ? 22 ?
2
Select R 7 =22. k, C 5 =0.47nF, and C 8 = 0pF for the design.
R
2
o
A C
20
g m
CA S O ESR O
2 π F P R 7 0 20
R 7 =
C 8 =
A C
g m
P IND = ( . ~ . 3 ) ? I 2O ? R DC
C 5 =
2 π F R
4
相关PDF资料 |
PDF描述 |
|---|---|
| SC4524BSETRT | IC REG BUCK 2A 8SOIC |
| 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 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| SC4524B | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:气门2A型降压型开关稳压器 |
| SC4524B_08 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:18V 2A Step-Down Switching Regulator |
| SC4524BEVB | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:18V 2A Step-Down Switching Regulator |
| SC4524BSETRT | 功能描述:IC REG BUCK 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: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 |
| 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 |
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