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参数资料
| 型号： | LTC3811EUHF#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 19/48页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 38-QFN |
| 标准包装： | 2,500 |
| 系列： | PolyPhase® |
| PWM 型： | 电流模式 |
| 输出数： | 2 |
| 频率 - 最大： | 850kHz |
| 占空比： | 90% |
| 电源电压： | 4.5 V ~ 30 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： | 38-WFQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
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LTC3811
OPERATION
(Refer to the Functional Diagram)
The typical capture range of the LTC3811’s PLL is ap-
proximately 125kHz to 1.1MHz, with a guarantee over
all manufacturing variations to be between 175kHz and
900kHz. The amplitude of the sync pulse to the LTC3811
should be greater than 1.8V and the minimum pulse width
should be greater than 200ns.
Using the CLKOUT and PHASEMODE Pins in
Multiphase Applications
The LTC3811 features two pins (CLKOUT and PHASEMODE)
that allow multiple LTC3811 ICs to be daisy-chained to-
gether in multiphase applications. The clock output signal
on the CLKOUT pin can be used to synchronize additional
power stages in a multiphase power supply solution feeding
a single high current output or even separate outputs. The
PHASEMODE pin is used to adjust the phase relationship
between channel 1 and channel 2, as well as the phase
relationship between channel 1 and CLKOUT, as summa-
rized in Table 3. The phases are calculated relative to the
Remote Sensing Using the Differential Ampli?er
The LTC3811 has a differential ampli?er for true remote
sensing of the output voltage. The sensing connections
should be returned from the load back to the differential
ampli?er’s inputs through a common, tightly coupled pair
of PCB traces. The differential ampli?er rejects common
mode signals capacitively or inductively radiated into the
feedback PCB traces, as well as ground loop disturbances.
The differential ampli?er output signal is typically divided
down and compared with the internal precision 0.6V volt-
age reference by the error ampli?er.
The differential ampli?er utilizes four precision internal
resistors to enable instrumentation-type measurement
of the output voltage. The ampli?er has a gain of 1.000,
contains a CMOS rail-to-rail output stage, and is optimized
for low input offset and high bandwidth.
The output voltage is set by an external resistive divider
according to the following formula:
V OUT = 0.6 ? ? 1 +
zero degrees, de?ned as the rising edge of the top gate
driver output of channel 1, TG1.
The PHASEMODE input comparators are referenced to an
?
?
R2 ?
R1 ? ?
internal divider from INTV CC that has 33% and 67% INTV CC
thresholds. For 6-phase operation, connect PHASEMODE
to an external divider from INTV CC with equal value resis-
tors (e.g., 100k), so that PHASEMODE is always 50% of
INTV CC .
Table 3
where R2 and R1 are the upper and lower divider resistors,
respectively. The differential ampli?er was optimized for
divider currents in the range of 100μA to 600μA, meaning
that R1 in the equation above should be 1k to 6k.
Using the LTC3811 Operational Error Ampli?ers in
Multiphase Applications
# PHASES
2
3
4
6
12
IC #
1
1
2
1
2
1
2
3
1
2
3
4
5
6
PHASEMODE
0V
INTV CC
0V
0V
0V
50% INTV CC
50% INTV CC
50% INTV CC
50% INTV CC
50% INTV CC
0V
50% INTV CC
50% INTV CC
50% INTV CC
CLKOUT CONNECTS TO
N/A
MODE/SYNC of IC # 2
N/A
MODE/SYNC of IC # 2
N/A
MODE/SYNC of IC # 2
MODE/SYNC of IC # 2
N/A
MODE/SYNC of IC # 2
MODE/SYNC of IC # 3
MODE/SYNC of IC # 4
MODE/SYNC of IC # 5
MODE/SYNC of IC # 6
N/A
The LTC3811 error ampli?ers are true operational ampli-
?ers, meaning that they have high DC gain and low output
impedance. In previous generations of multiphase control-
lers, such as the LTC1628 family, the error ampli?ers were
transconductance ampli?ers, meaning that they could be
connected in parallel for multiphase applications.
Multiphase applications using the LTC3811 will use one
operational error ampli?er as the master and will disable
all of the slave phase error ampli?ers. Typically, the chan-
nel 1 ampli?er for phase = 0o will be used as the master
and phases 2 through n (up to 12 phases) will serve as
slaves. To disable the slave error ampli?ers but still use
their current comparators and power stages, connect the
3811f
19
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相关代理商/技术参数 |
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| LTC3812EFE5#PBF | 制造商:Linear Technology 功能描述: |
| LTC3812EFE-5#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 16TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 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 |
| LTC3812EFE-5#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 16TSSOP 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) |
| LTC3812IFE-5#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 16TSSOP 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) |
| LTC3812IFE-5#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 16TSSOP 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) |
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