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參數(shù)資料
| 型號(hào)： | LTC3538EDCB |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 0.8 A SWITCHING REGULATOR, 1200 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | 2 X 3 MM, PLASTIC, DFN-8 |
| 文件頁數(shù)： | 15/16頁 |
| 文件大?。?/td> | 206K |
| 代理商： | LTC3538EDCB |
LTC3538
8
3538fb
OPERATION
The LTC3538 provides high efciency, low noise power
for a wide variety of handheld electronic devices. The LTC
proprietary topology allows input voltages above, below
and equal to the output voltage through proper phasing
of the four on-chip MOSFET switches. The error amplier
output voltage on VCdeterminestheoutputdutycycleofthe
switches. Since VC is a ltered signal, it provides rejection
of frequencies from well below the switching frequency.
The low RDS(ON), low gate charge synchronous switches
provide high frequency pulse width modulation control at
high efciency. High efciency is achieved at light loads
when Burst Mode operation is selected.
LOW NOISE FIXED FREQUENCY OPERATION
Operating Frequency
The operating frequency is internally xed to 1MHz to
maximize overall converter efciency while minimizing
external component size.
Error Amplier
The error amplier controls the duty cycle of the internal
switches. The loop compensation components are con-
gured around the amplier to provide converter loop
stability. Pulling down the output of the error amplier
(VC) below 0.25V will disable the LTC3538. In shutdown
the LTC3538 will draw only 1.5μA typical from the input
supply. During normal operation the VC pin should be
allowed to oat.
Soft-Start
The converter has an internal voltage mode soft-start
circuit with a nominal duration of 1.5ms. The converter
remains in regulation during soft-start and will therefore
respond to output load transients that occur during this
time. In addition, the output voltage risetime has minimal
dependency on the size of the output capacitor or load.
During soft-start, the converter is forced into PWM
operation regardless of the state of the BURST pin.
Internal Current Limit
There are two current limit circuits in the LTC3538. The rst
is a high speed peak current limit amplier that will shut
off switch A once the input current exceeds ~
3.5A typical.
The delay to output of this amplier is typically 50ns.
The second current limit sources current out of the FB pin
to drop the output voltage once the input average current
exceeds 2A typical. This method provides a closed loop
means of clamping the input current. During conditions
when VOUT is near ground, such as during a short circuit
or during start-up, this threshold is cut to 1A typical,
providing a foldback feature to limit power dissipation. For
this current limit feature to be most effective, the Thevenin
resistance (typically the parallel combination of R1 and
R2) from FB to ground should be greater than 100k.
Reverse Current Limit
During xed frequency operation, the LTC3538 operates in
forced continuous conduction mode. The reverse current
limit comparator monitors the inductor current from the
output through switch D. Should this negative inductor
current exceed 500mA typical, the LTC3538 shuts off
switch D.
Four-Switch Control
SW1
SW2
VIN
VOUT
NMOS B
NMOS C
PMOS A
L1
PMOS D
3538 FO1
8
5
6
7
Figure 1. Simplied Diagram of Output Switches
Figure 1 shows a simplied diagram of how the four internal
switches are connected to the inductor, VIN, VOUT and GND.
Figure 2 shows the regions of operation for the LTC3538
as a function of the internal control voltage.
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| LTC3538EDCB#PBF | 制造商:Linear Technology 功能描述:DC-DC CONV BUCK/BOOST 8000mA DFN-8 制造商:Linear Technology 功能描述:DC-DC CONV, BUCK/BOOST, 8000mA, DFN-8 制造商:Linear Technology 功能描述:DC-DC CONV, BUCK/BOOST, 8000mA, DFN-8, Primary Input Voltage:5.5V, No. of Outputs:1, Output Current:800mA, No. of Pins:8, Operating Temperature Min:-40C, Operating Temperature Max:85C, MSL:MSL 1 - Unlimited, Package / Case:8-DFN , RoHS Compliant: Yes 制造商:Linear Technology 功能描述:DP-SWREG/Monolithic, Cut Tape 800mA, 1MHz Wide Input Voltage Synch Buck-Boost DC |
| LTC3538EDCB#TRMPBF | 功能描述:IC REG BUCK BOOST SYNC ADJ 8DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:250 系列:- 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V 輸入電壓:2.05 V ~ 6 V PWM 型:電壓模式 頻率 - 開關(guān):2MHz 電流 - 輸出:500mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:6-UFDFN 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:6-SON（1.45x1） 產(chǎn)品目錄頁面:1032 (CN2011-ZH PDF) 其它名稱:296-25628-2 |
| LTC3538EDCB#TRPBF | 功能描述:IC REG BUCK BOOST SYNC ADJ 8DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V，1.5V，1.8V，2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬）裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤 |
| LTC3538EDCB-PBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:800mA Synchronous Buck-Boost DC/DC Converter |
| LTC3538EDCB-TR | 制造商:LINER 制造商全稱:Linear Technology 功能描述:800mA Synchronous Buck-Boost DC/DC Converter |
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