- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄44986 > LT3740EDHC (LINEAR TECHNOLOGY CORP) 0.14 A SWITCHING CONTROLLER, 330 kHz SWITCHING FREQ-MAX, PDSO16 PDF資料下載
參數(shù)資料
| 型號(hào)： | LT3740EDHC |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 0.14 A SWITCHING CONTROLLER, 330 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封裝： | 5 X 3 MM, PLASTIC, MO-229WJED-1, DFN-16 |
| 文件頁(yè)數(shù)： | 19/20頁(yè) |
| 文件大小： | 234K |
| 代理商： | LT3740EDHC |
第1頁(yè)第2頁(yè)第3頁(yè)第4頁(yè)第5頁(yè)第6頁(yè)第7頁(yè)第8頁(yè)第9頁(yè)第10頁(yè)第11頁(yè)第12頁(yè)第13頁(yè)第14頁(yè)第15頁(yè)第16頁(yè)第17頁(yè)第18頁(yè)當(dāng)前第19頁(yè)第20頁(yè)
LT3740
8
3740fc
Current Sensing Range
Inductor current is determined by measuring the voltage
across a sense resistance – either the on-resistance of
the bottom MOSFET or an external sensing resistor. The
maximum current sense threshold has three steps that are
selected by the RANGE pin. The current sense threshold
voltage without slope compensation is shown in Table 1.
This is the value for high duty cycle operation.
Table 1. Current Sensing Thresholds
RANGE PIN
CURRENT SENSING THRESHOLD
Ground
50mV
Open
80mV
VIN
105mV
Slope Compensation
The LT3740 has a compensation slope to stabilize the
constant-frequency valley mode operation. The slope
compensation signal increases with the bottom gate duty
cycle, which results in a current sense threshold voltage
change with duty cycle as shown in the gure in Typical
Performance Characteristics. The three current limit levels
correspond to three compensation slopes.
The compensation slope needs to overcome the difference
between the up and down slope of the inductor current
to avoid sub-harmonic oscillation. Maximum compensa-
tion slope is required for high input voltages, where the
duty cycle is small. The compensation slope can only be
selected by the RANGE pin. In the case of insufcient
compensation slope, the inductor ripple current or the
sensing resistance needs to be reduced.
Reverse Current Limit
Because the LT3740 operates in forced continuous mode
when the feedback voltage is higher than 720mV, the
inductor current can go negative on occasion, such as
light load, shutting down with a slow SHDN signal, large
load step-down transient response, or the output voltage
being pulled up by some other power supply. The LT3740
has a reverse current comparator to limit the reverse
current. During the on-time of the bottom MOSFET, when
(VSN+)–(VSN–) reaches 40mV, the comparator is triggered
and turns off the bottom MOSFET.
When operated under light load, the inductor current goes
negative every cycle. The design of the inductor current
ripple and the sensing resistor need to ensure that the
reverse current comparator is not triggered during normal
operation.
Power MOSFET Selection
The LT3740 requires two external N-channel power
MOSFETs, one for the top switch and one for the bottom
switch. Important parameters for the power MOSFETs are
the breakdown voltage V(BR)DSS,thresholdvoltageV(GS)TH,
on-resistance RDS(ON), reverse transfer capacitance CRSS
and maximum current IDS(MAX).
When the bottom MOSFET is used as the current sense
element, particular attention must be paid to the initial varia-
tion, the gate-source voltage effect and the temperature
characteristics of its on-resistance. MOSFET on-resistance
decreases as the gate-source voltage increases. The change
of BGDP voltage could affect the bottom MOSFET gate
voltage. Refer to the MOSFET datasheet for the MOSFET
on-resistance corresponding to certain gate voltage.
MOSFET on-resistance is typically specied with a
maximum value RDS(ON) at 25°C. In this case, additional
margin is required to accommodate the rise in MOSFET
on-resistance with temperature:
RDS(ON) = RSENSE/ρT
APPLICATIONS INFORMATION
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LT3741EFE#PBF | SWITCHING CONTROLLER, 1070 kHz SWITCHING FREQ-MAX, PDSO20 |
| LT3741IFE#TRPBF | SWITCHING CONTROLLER, 1070 kHz SWITCHING FREQ-MAX, PDSO20 |
| LT3741EUF#PBF | SWITCHING CONTROLLER, 1070 kHz SWITCHING FREQ-MAX, PQCC20 |
| LT3741EUF#TRPBF | SWITCHING CONTROLLER, 1070 kHz SWITCHING FREQ-MAX, PQCC20 |
| LT3741IUF#PBF | SWITCHING CONTROLLER, 1070 kHz SWITCHING FREQ-MAX, PQCC20 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT3740EDHC#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 16-DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 特色產(chǎn)品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 標(biāo)準(zhǔn)包裝:1 系列:PowerWise® PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.5 V ~ 18 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-5°C ~ 125°C 封裝/外殼:32-WFQFN 裸露焊盤 包裝:Digi-Reel® 產(chǎn)品目錄頁(yè)面:1303 (CN2011-ZH PDF) 其它名稱:LM3754SQDKR |
| LT3740EDHC#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 16-DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR) |
| LT3740EDHC-PBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Wide Operating Range, Valley Mode, No RSENSE? Synchronous Step-Down Controller |
| LT3740EDHC-TR | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Wide Operating Range, Valley Mode, No RSENSE? Synchronous Step-Down Controller |
| LT3740EDHC-TRPBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Wide Operating Range, Valley Mode, No RSENSE? Synchronous Step-Down Controller |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。