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参数资料
| 型号： | LTC1143CS |
| 厂商： | Linear Technology |
| 文件页数： | 11/20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
but δ = 0.005/ ° C can be used as an approximation for low
voltage MOSFETs.
RMS current must be used. The maximum RMS capacitor
current is given by:
[ (
) ]
When selecting the P-channel power MOSFET for each
section, consideration should be given to using a dual MOSFET
with the other half used for the second regulator. Assuming
both sections are operating at similar currents, the required
C IN Required I RMS ≈ I MAX
V OUT V IN ? V OUT
V IN
1 / 2
R DS(ON) will be half the value of a single MOSFET to stay within
the package dissipation limit. Remember that worst-case
MOSFET dissipation occurs at minimum V IN .
Output Diode Selection (D1, D2)
The Schottky diodes D1 and D2 shown in Figure 1 conduct
during the off-time. It is important to adequately specify
the diode peak current and average power dissipation to
not exceed the diode ratings.
The most stressful condition for the output diode is under
short circuit (V OUT = 0V). Under this condition the diode
must safely handle I SC(PK) at close to 100% duty cycle.
Under normal load conditions the average current con-
ducted by the diode is:
This formula has a maximum at V IN = 2V OUT , where I RMS
= I OUT /2. This simple worst-case condition is commonly
used for design because even significant deviations do not
offer much relief. Note that capacitor manufacturer’s
ripple current ratings are often based on only 2000 hours
of life. This makes it advisable to further derate the
capacitor, or to choose a capacitor rated at a higher
temperature than required. Several capacitors may also be
paralleled to meet size or height requirements in the
design. Always consult the manufacturer if there is any
question. An additional 0.1 μ F to 1 μ F ceramic capacitor is
also required on each V IN line (Pins 5, 13) for high
frequency decoupling.
( V IN OUT D V ) ( I LOAD )
I DIODE =
? V +
V IN
The selection of C OUT is driven by the required (ESR). The
ESR of C OUT must be less than twice the value of R SENSE
for proper operation of the LTC1143 series:
Remember to keep lead lengths short and observe proper
grounding (see Board Layout Checklist) to avoid ringing
and increased dissipation.
The forward voltage drop allowable in the diode is calcu-
lated from the maximum short-circuit current as:
C OUT Required ESR < 2R SENSE
Optimum efficiency is obtained by making the ESR equal
to R SENSE . As the ESR is increased up to 2R SENSE the
efficiency degrades by less than 1%. If the ESR is greater
than 2R SENSE , the voltage ripple on the output capacitor
will prematurely trigger Burst Mode operation, resulting in
V F ≈
P D
I SC ( PK )
disruption of continuous mode and an efficiency hit which
can be several percent.
Manufacturers such as Nichicon and United Chemicon
where P D is the allowable power dissipation and will be
determined by efficiency and/or thermal requirements
(see Efficiency Considerations).
C IN and C OUT Selection
In continuous mode, the source current of the P-channel
MOSFET is a square wave of duty cycle V OUT / V IN . To
prevent large voltage transients, a low effective series
resistance (ESR) input capacitor sized for the maximum
should be considered for high performance capacitors.
The OS-CON semiconductor dielectric capacitor available
from Sanyo has the lowest ESR size/ratio of any aluminum
electrolytic at a somewhat higher price. Once the ESR
requirement for C OUT has been met, the RMS current
rating generally far exceeds the I RIPPLE(P-P) requirement.
In surface mount applications multiple capacitors may
have to be parallel to meet the capacitance, ESR or RMS
current handling requirements of the application.
11
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|---|---|
| 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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