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参数资料
| 型号： | LTC3569EFE#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 2.5 A SWITCHING REGULATOR, 3000 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封装： | 4.40 MM, LEAD FREE, PLASTIC, TSSOP-16 |
| 文件页数： | 3/26页 |
| 文件大小： | 468K |
| 代理商： | LTC3569EFE#PBF |
LTC3569
11
3569fd
OPERATION
(NCOMP) signals to turn-off the N-channel switch, so
that is does not discharge the output capacitor. When a
rising clock edge occurs, the P-channel switch turns on
repeating the cycle.
Thepeakinductorcurrentiscontrolledbytheerroramplifier
(EA)andisinfluencedbytheslopecompensation.Theerror
amplifier compares the FB pin voltage to the programmed
internal reference (REF). When the load current increases,
the FB voltage decreases. When the FB voltage falls below
the reference voltage, the error amplifier output rises
to increase the peak inductor current until the average
inductor current matches the new load current. With the
inductor current equal to the load current, the duty cycle
will stabilize to a value equal to VOUT/VIN.
Low Current Operation
At light loads, the FB voltage may rise above the refer-
ence voltage. If this occurs the error amplifier signals
the control loop to go to sleep, and the P-channel turns
off immediately. The inductor current then discharges
through the N-channel switch until the inductor current
approaches zero; whereupon the SW goes Hi-Z, and the
output capacitor supplies power to the load. When the
load discharges the output capacitor the feedback voltage
falls and the error amp wakes up the buck, restarting the
main control loop as if a clock cycle has just begun. This
sleep cycle helps minimize the switching losses which are
dominated by the gate charge losses of the power devices.
Two operating modes are available to control the operation
of the LTC3569 at low currents, Burst Mode operation and
pulse-skipping mode.
Select Burst Mode operation to optimize efficiency at low
output currents. In Burst Mode operation the inductor cur-
rent reaches a fixed current before the P-channel switch
compares inductor current against the value determined
by ITH. This burst clamp causes the output voltage to rise
above the regulation voltage and forces a longer sleep
cycle. This greatly reduces switching losses and aver-
age quiescent current at light loads, at the cost of higher
ripple voltage.
Pulse-skipping mode is intended for lower output voltage
ripple at light load currents. Here, the peak P-channel cur-
rent is compared with the value determined by the error
amplifier output. Then, the P-channel is turned off and the
N-channel switch is turned on until either the next cycle
beginsortheN-channelcomparator(NCOMP)turnsoffthe
N-channel switch. If the NCOMP trips, the SW node goes
Hi-Z and the buck operates discontinuously. In pulse-skip-
ping mode the LTC3569 continues to switch at a constant
frequency down to very low currents; where it eventually
begins skipping pulses. Because the LTC3569 remains
active at lighter load currents in pulse-skipping mode, the
efficiency performance is traded off against output voltage
ripple and electromagnetic interference (EMI).
Dropout Operation
When the input supply voltage decreases towards the out-
putvoltagethedutycycleautomaticallyincreasesto100%;
which is the dropout condition. In dropout, the P-channel
switch is turned on continuously with the output voltage
being equal to the input voltage minus the voltage drop
across the internal P-channel switch and the inductor.
Low Supply Operation
The LTC3569 incorporates an undervoltage lockout circuit
which shuts down the part when the input voltage drops
below 2.5V to prevent unstable operation. The UVLO
function does not reset the reference voltage DAC. (See
Programming the Reference.)
Slave Power Stage
When the FB pin of one of the two 600mA regulators is tied
to SVIN that regulator’s control circuits are disabled and
the regulator’s switch pin is configured to follow a master
regulator; either the first 600mA regulator (regulator 2) or
the 1.2A regulator (regulator 1). In this way, two regula-
tor power stages are ganged together (e.g., switch pins
shorted together to a single inductor) to support higher
current levels. This permits three permutations of power
levels: three independent regulators at 1.2A, 600mA and
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相关代理商/技术参数 |
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| LTC3569EFE-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Triple Buck Regulator With 1.2A and Two 600mA Outputs and Individual Programmable References |
| LTC3569EUD#PBF | 功能描述:IC REG BUCK SYNC ADJ TRPL 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:250 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V 输入电压:2.05 V ~ 6 V PWM 型:电压模式 频率 - 开关:2MHz 电流 - 输出:500mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:6-UFDFN 包装:带卷 (TR) 供应商设备封装:6-SON（1.45x1） 产品目录页面:1032 (CN2011-ZH PDF) 其它名称:296-25628-2 |
| LTC3569EUD#TRPBF | 功能描述:IC REG BUCK SYNC ADJ TRPL 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 |
| LTC3569EUDC#PBF | 功能描述:IC REG BUCK SYNC ADJ TRPL 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 |
| LTC3569EUDC#TRPBF | 功能描述:IC REG BUCK SYNC ADJ TRPL 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 |
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