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参数资料
| 型号： | LTC1143CS |
| 厂商： | Linear Technology |
| 文件页数： | 9/20页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 16-SOIC |
| 标准包装： | 50 |
| PWM 型： | 电流模式 |
| 输出数： | 2 |
| 频率 - 最大： | 400kHz |
| 占空比： | 100% |
| 电源电压： | 3.5 V ~ 16 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 16-SOIC（0.154"，3.90mm 宽） |
| 包装： | 管件 |
| 其它名称： | LTC1143CSW LTC1143CSW-ND |
LTC1143/LTC1143L
LTC1143L-ADJ
APPLICATIO N S I N FOR M ATIO N
? V + V ?
1 . 3 10 4 ? f ?
0.20
0.15
C T =
? IN D ?
? ?
1 ? V IN ? V OUT ?
0.10
0.05
where V D is the drop across the diode.
A graph for selecting C T versus frequency including the
effects of input voltage is given in Figure 3.
0
0
1
2
3
4
5
1000
V SENSE = V OUT = 5V
MAXIMUM OUTPUT CURRENT (A)
1143 F02
800
Figure 2. Selecting R SENSE
600
The load current below which Burst Mode operation
400
V IN = 12V
commences, I BURST , and the peak short circuit current,
I SC(PK) , both track I MAX . Once R SENSE has been chosen,
200
V IN = 7V
V IN = 10V
I BURST and I SC(PK) can be predicted from the following:
0
0
50
100
150 200
250
300
I BURST ≈ 15mV
R SENSE
I SC(PK) = 150mV
R SENSE
The LTC1143 series automatically extends t OFF during a
short circuit to allow sufficient time for the inductor
FREQUENCY (kHz)
LTC1143 F03
Figure 3. Timing Capacitor Value
As the operating frequency is increased the gate charge
losses will be higher, reducing efficiency (see Efficiency
Considerations). The complete expression for operating
frequency of the circuit in Figure 1 is given by:
? 1 ? V
t OFF ?
IN ?
current to decay between switch cycles. The resulting
I SC(AVG) to be reduced to approximately I MAX .
L and C T Selection for Operating Frequency
f ≈
1 ? V OUT ?
?
= 1 . 3 10 4 ? C
? V ?
t OFF T ? REG ?
? V
?
? ?
Each regulator section of the LTC1143 series uses a
constant off-time architecture with t OFF determined by an
external timing capacitor C T . Each time the P-channel
MOSFET switch turns on the voltage on C T is reset to
approximately 3.3V. During the off-time, C T is discharged
by a current that is proportional to V OUT . The voltage on C T
is analogous to the current in inductor L, which likewise
decays at a rate proportional to V OUT . Thus the inductor
value must track the timing capacitor value.
The value of C T is calculated from the desired continuous
mode operating frequency:
where:
?
OUT
V REG is the desired output voltage (i.e., 5V, 3.3V). V OUT
is the measured output voltage. Thus V REG /V OUT = 1 in
regulation.
Note that as V IN decreases, the frequency decreases.
When the input-to-output voltage differential drops below
1.5V for a particular section, the LTC1143 series reduces
t OFF in that section by increasing the discharge current in
C T . This prevents audible operation prior to dropout.
9
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC1143CS#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 16-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC1143CS#TR | 功能描述:IC REG CTRLR BUCK PWM CM 16-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC1143CS#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 16-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC1143L | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual High Efficiency SO-16 Step-Down Switching Regulator Controllers |
| LTC1143L-ADJ | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual High Efficiency SO-16 Step-Down Switching Regulator Controllers |
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