- 您现在的位置：买卖IC网 > PDF目录15302 > LTC3856EUH#PBF (Linear Technology)IC REG CTRLR BUCK PWM CM 32WFQFN PDF资料下载
参数资料
| 型号： | LTC3856EUH#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 14/40页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 32WFQFN |
| 标准包装： | 73 |
| 系列： | PolyPhase® |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 850kHz |
| 占空比： | 94% |
| 电源电压： | 4.5 V ~ 38 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 ~ 125°C |
| 封装/外壳： | 32-WFQFN 裸露焊盘 |
| 包装： | 管件 |
第1页第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页当前第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
LTC3856
OPERATION (Refer to Functional Diagram)
operating frequency from 250kHz to 770kHz. There is a
precision 10μA current flowing out of the FREQ pin enabling
the user to program the controller’s switching frequency
with a single resistor to SGND. A curve is provided later in
the Applications Information section showing the relation-
ship between the voltage on the FREQ pin and switching
frequency.
A phase-locked loop (PLL) is available on the LTC3856
to synchronize the internal oscillator to an external clock
source that is connected to the PLLIN pin. The PLL loop
filter network is integrated inside the LTC3856. The
phase-locked loop is capable of locking any frequency
within the range of 250kHz to 770kHz. The frequency
setting resistor should always be present to set the
controller’s initial switching frequency before locking to
the external clock.
Sensing the Output Voltage with a Differential Amplifier
The LTC3856 includes a low offset, unity-gain, high band-
width differential amplifier for applications that require true
remote sensing. Sensing the load across the load capaci-
tors directly greatly benefits regulation in high current, low
voltage applications, where board interconnection losses
can be a significant portion of the total error budget.
The LTC3856 differential amplifier has a typical output slew
rate of 2V/μs. The amplifier is configured for unity gain,
meaning that the difference between DIFFP and DIFFN is
translated to DIFFOUT, relative to SGND.
Care should be taken to route the DIFFP and DIFFN PCB
traces parallel to each other all the way to the terminals
of the output capacitor or remote sensing points on the
board. In addition, avoid routing these sensitive traces
near any high speed switching nodes in the circuit. Ideally,
the DIFFP and DIFFN traces should be shielded by a low
impedance ground plane to maintain signal integrity.
The maximum output voltage when using the differential
amplifier is INTV CC – 1.4V (typically 3.6V). The differential
amplifier should not be used above this voltage.
Power Good (PGOOD Pin)
The PGOOD pin is connected to an open drain of an internal
N-channel MOSFET. The MOSFET turns on and pulls the
PGOOD pin low when either V FB pin voltage is not within
±10% of the 0.6V reference voltage. The PGOOD pin is
also pulled low when the RUN pin is below 1.22V or when
the LTC3856 is in the soft-start or tracking phase. When
the V FB pin voltage is within the ±10% regulation window,
the MOSFET is turned off and the pin is allowed to be
pulled up by an external resistor to a source of up to 6V.
The PGOOD pin will flag power good immediately when
V FB is within the regulation window. However, there is an
internal 20μs power-bad mask when V FB goes out of the
regulation window.
Output Overvoltage Protection
An overvoltage comparator, OV, guards against transient
overshoots (>10%) as well as other more serious condi-
tions that may overvoltage the output. In such cases, the
top MOSFET is turned off and the bottom MOSFET is turned
on until the overvoltage condition is cleared.
Undervoltage Lockout
The LTC3856 has two functions that help protect the
controller in case of undervoltage conditions. A precision
UVLO comparator constantly monitors the INTV CC voltage
to ensure that an adequate gate-drive voltage is present. It
locks out the switching action when INTV CC is below 3.2V.
To prevent oscillation when there is a disturbance on the
INTV CC , the UVLO comparator has 600mV of precision
hysteresis.
Another way to detect an undervoltage condition is
to monitor the V IN supply. Because the RUN pin has
a precision turn-on reference of 1.22V, one can use a
resistor divider to V IN to turn on the IC when V IN is high
enough. An extra 4.5μA of current flows out of the RUN
pin once the RUN pin voltage passes 1.22V. The RUN
comparator itself has about 80mV of hysteresis. One
can program additional hysteresis for the RUN com-
parator by adjusting the values of the resistive divider.
For accurate V IN undervoltage detection, V IN needs to
be higher than 4.5V.
3856f
相关PDF资料 |
PDF描述 |
|---|---|
| EYM25DRSS | CONN EDGECARD 50POS DIP .156 SLD |
| VE-254-EW-F2 | CONVERTER MOD DC/DC 48V 100W |
| EGM25DRSS | CONN EDGECARD 50POS DIP .156 SLD |
| LTC3866EFE#TRPBF | IC REG CTRLR BUCK PWM CM 24TSSOP |
| EEM43DREF | CONN EDGECARD 86POS .156 EYELET |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3856IFE#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 38TFSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 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 ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC3856IFE#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 38TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 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 ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC3856IUH#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 32WFQFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 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) |
| LTC3856IUH#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 38-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 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) |
| LTC3857EGN-1#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 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:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
发布紧急采购，3分钟左右您将得到回复。