- 您现在的位置：买卖IC网 > PDF目录79982 > LT3579EFE-1#PBF (LINEAR TECHNOLOGY CORP) SWITCHING REGULATOR, PDSO20 PDF资料下载
参数资料
| 型号： | LT3579EFE-1#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING REGULATOR, PDSO20 |
| 封装： | 4.40 MM, LEAD FREE, PLASTIC, TSSOP-20 |
| 文件页数： | 2/40页 |
| 文件大小： | 503K |
| 代理商： | LT3579EFE-1#PBF |
第1页当前第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页
LT3579/LT3579-1
10
35791f
operaTion
OPERATION – OVERVIEW
The LT3579 uses a constant-frequency, current mode
controlschemetoprovideexcellentlineandloadregulation.
Thepart’sundervoltagelockout(UVLO)function,together
with soft-start and frequency foldback, offers a controlled
means of starting up. Fault features are incorporated in
the LT3579 to aid in the detection of output shorts, over-
voltage,andovertemperatureconditions.RefertotheBlock
Diagram (Figure 1) and the State Diagram (Figure 2) for
the following description of the part’s operation.
OPERATION – START-UP
Several functions are provided to enable a very clean
start-up for the LT3579.
Precise Turn-On Voltage
The SHDN pin compares to an internal voltage reference to
give a precise turn on voltage level. Taking the SHDN pin
above1.33V(typical)enablesthepart.TakingtheSHDNpin
below0.3Vshutsdownthechip,resultinginextremelylow
quiescent current. The SHDN pin has 30mV of hysteresis
to protect against glitches and slow ramping.
Undervoltage-Lockout (UVLO)
The SHDN pin can also be used to create a configurable
UVLO.TheUVLOfunctionsetstheturnon/offoftheLT3579
at a desired input voltage (VINUVLO). Figure 3 shows how
a resistor divider (or single resistor) from VIN to the SHDN
pin can be used to set VINUVLO. RUVLO2 is optional. It may
be left out, in which case set it to infinite in the equation
below. For increased accuracy, set RUVLO2 ≤ 10k. Pick
RUVLO1 as follows:
RUVLO1 =
VINUVLO –1.33V
1.33V
RUVLO2
+ 11.6A
RUVLO2
(OPTIONAL)
1.33V
RUVLO1
35791 F03
VIN
ACTIVE/
LOCKOUT
GND
11.6A
AT 1.33V
–
+
SHDN
Figure 3. Configurable UVLO
The LT3579 also has internal UVLO circuitry that disables
the chip when VIN < 2.3V (typical).
Soft-Start of Switch Current
The soft-start circuitry provides for a gradual ramp-up of
theswitchcurrent(refertoCommandedSwitchCurrentvs.
SS in Typical Performance Characteristics). When the part
is brought out of shutdown, the external SS capacitor is
first discharged which resets the states of the logic circuits
in the chip. Then an integrated 250k resistor pulls the SS
pin to ~1.8V at a ramp rate set by the external capacitor
connected to the pin. Once SS gets to 1.8V, the CLKOUT
pin is enabled, and an internal regulator pulls the pin up
quickly to ~2.1V. Typical values for the external soft-start
capacitor range from 100nF to 1μF.
Soft-Start of External PMOS (if used)
The soft-start circuitry also gradually ramps up the GATE
pin pull-down current which allows an external PMOS
to slowly turn on (M1 in Block Diagram). The GATE pin
currentincreaseslinearlywithSSvoltage,withamaximum
current of 933A when the SS voltage gets above 500mV.
Note that if the GATE pin voltage is less than 2V for SS
voltages exceeding 500mV, then the GATE pin impedance
to ground is 2k. The soft turn on of the external PMOS
helps limit inrush current at start-up, making hot plugs
of the LT3579 feasible and safe.
相关PDF资料 |
PDF描述 |
|---|---|
| LTC3521IFE#TRPBF | SWITCHING REGULATOR, 1350 kHz SWITCHING FREQ-MAX, PDSO20 |
| LS4501-9PD6TB1 | 1-OUTPUT 100 W AC-DC PWR FACTOR CORR MODULE |
| LK2320-7EPD2TB1 | 2-OUTPUT 150 W AC-DC REG PWR SUPPLY MODULE |
| LK2540-7EPD2TB1 | 2-OUTPUT 150 W AC-DC REG PWR SUPPLY MODULE |
| LS1001-7EPD7T | 1-OUTPUT 100 W AC-DC REG PWR SUPPLY MODULE |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3579EFE-1-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:6A Boost/Inverting DC/DC Converter with Fault Protection |
| LT3579EFE-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:6A Boost/Inverting DC/DC Converter with Fault Protection |
| LT3579EFE-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:6A Boost/Inverting DC/DC Converter with Fault Protection |
| LT3579EUFD#PBF | 功能描述:IC REG MULTI CONFIG SYNC 20QFN 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:2,500 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V，1.5V，1.8V，2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘 |
| LT3579EUFD#TRPBF | 功能描述:IC REG MULTI CONFIG SYNC 20QFN 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:2,500 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V，1.5V，1.8V，2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘 |
发布紧急采购，3分钟左右您将得到回复。