- 您现在的位置：买卖IC网 > PDF目录15239 > LTC3827IG-1#PBF (Linear Technology)IC REG CTRLR BUCK PWM CM 28-SSOP PDF资料下载
参数资料
| 型号： | LTC3827IG-1#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 11/32页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 28-SSOP |
| 标准包装： | 47 |
| 系列： | PolyPhase® |
| PWM 型： | 电流模式 |
| 输出数： | 2 |
| 频率 - 最大： | 580kHz |
| 占空比： | 99.4% |
| 电源电压： | 4 V ~ 36 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： | 28-SSOP（0.209"，5.30mm 宽） |
| 包装： | 管件 |
| 产品目录页面： | 1336 (CN2011-ZH PDF) |
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页当前第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
LTC3827-1
OPERATION (Refer to Functional Diagram)
When the I TH voltage drops below 0.4V, the internal sleep
signal goes high (enabling “sleep” mode) and both external
MOSFETs are turned off. The I TH pin is then disconnected
from the output of the EA and “parked” at 0.425V.
In sleep mode, much of the internal circuitry is turned off,
reducing the quiescent current that the LTC3827-1 draws.
If one channel is shut down and the other channel is in
sleep mode, the LTC3827-1 draws only 80μA of quiescent
current. If both channels are in sleep mode, the LTC3827-1
draws only 115μA of quiescent current. In sleep mode,
the load current is supplied by the output capacitor. As
the output voltage decreases, the EA’s output begins to
rise. When the output voltage drops enough, the I TH pin
is reconnected to the output of the EA, the sleep signal
goes low, and the controller resumes normal operation
by turning on the top external MOSFET on the next cycle
of the internal oscillator.
When a controller is enabled for Burst Mode operation,
the inductor current is not allowed to reverse. The reverse
current comparator (IR) turns off the bottom external
MOSFET just before the inductor current reaches zero,
preventing it from reversing and going negative. Thus, the
controller operates in discontinuous operation.
In forced continuous operation, the inductor current is
allowed to reverse at light loads or under large transient
conditions. The peak inductor current is determined by
the voltage on the I TH pin, just as in normal operation.
In this mode, the ef?ciency at light loads is lower than
in Burst Mode operation. However, continuous has the
advantages of lower output ripple and less interference
to audio circuitry. In forced continuous mode, the output
ripple is independent of load current.
When the PLLIN/MODE pin is connected for pulse-skipping
mode or clocked by an external clock source to use the
phase-locked loop (see Frequency Selection and Phase-
Locked Loop section), the LTC3827-1 operates in PWM
pulse-skipping mode at light loads. In this mode, constant
frequency operation is maintained down to approximately
1% of designed maximum output current. At very light
loads, the current comparator I CMP may remain tripped for
several cycles and force the external top MOSFET to stay
off for the same number of cycles (i.e., skipping pulses).
The inductor current is not allowed to reverse (discon-
tinuous operation). This mode, like forced continuous
operation, exhibits low output ripple as well as low audio
noise and reduced RF interference as compared to Burst
Mode operation. It provides higher low current ef?ciency
than forced continuous mode, but not nearly as high as
Burst Mode operation.
Frequency Selection and Phase-Locked Loop (PLLLPF
and PLLIN/MODE Pins)
The selection of switching frequency is a tradeoff between
ef?ciency and component size. Low frequency opera-
tion increases ef?ciency by reducing MOSFET switching
losses, but requires larger inductance and/or capacitance
to maintain low output ripple voltage.
The switching frequency of the LTC3827-1’s controllers
can be selected using the PLLLPF pin.
If the PLLIN/MODE pin is not being driven by an external
clock source, the PLLLPF pin can be ?oated, tied to INTV CC ,
or tied to SGND to select 400kHz, 530kHz, or 250kHz,
respectively.
A phase-locked loop (PLL) is available on the LTC3827-1
to synchronize the internal oscillator to an external clock
source that is connected to the PLLIN/MODE pin. In this
case, a series R-C should be connected between the
PLLLPF pin and SGND to serve as the PLL’s loop ?lter.
The LTC3827-1 phase detector adjusts the voltage on the
PLLLPF pin to align the turn-on of controller 1’s external
top MOSFET to the rising edge of the synchronizing signal.
Thus, the turn-on of controller 2’s external top MOSFET is
180 degrees out of phase to the rising edge of the external
clock source.
The typical capture range of the LTC3827-1’s phase-locked
loop is from approximately 115kHz to 800kHz, with a
guarantee over all manufacturing variations to be between
140kHz and 650kHz. In other words, the LTC3827-1’s PLL
is guaranteed to lock to an external clock source whose
frequency is between 140kHz and 650kHz.
The typical input clock thresholds on the PLLIN/MODE
pin are 1.6V (rising) and 1.2V (falling).
38271fe
11
相关PDF资料 |
PDF描述 |
|---|---|
| H2BBT-10108-W4-ND | JUMPER-H1500TR/A2015W/H1500TR 8" |
| ELL-6GM470M | COIL PWR CHOKE 47UH 420MA SMD |
| SRP1040-6R8M | INDUCTOR 6.8UH 6.5A SMD |
| SRP1040-5R6M | INDUCTOR 5.6UH 7A SMD |
| LTC1148CS-3.3 | IC REG CTRLR BUCK PWM CM 14-SOIC |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3827IUH#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 32-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: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 |
| LTC3827IUH#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 32-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: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 |
| LTC3828EG#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® 标准包装:2,000 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:1MHz 占空比:50% 电源电压:9 V ~ 10 V 降压:无 升压:是 回扫:是 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:8-TSSOP（0.173"，4.40mm 宽） 包装:带卷 (TR) |
| LTC3828EG#TRPBF | 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® 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 |
| LTC3828EUH | 制造商:Linear Technology 功能描述:DC DC Cntrlr Dual-OUT Sync Step Down 4.5V to 28V Input 32-Pin QFN EP |
发布紧急采购，3分钟左右您将得到回复。