- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄377775 > LTC3548EMSE (LINEAR TECHNOLOGY CORP) Dual Synchronous,400mA/800mA, 2.25MHz Step-Down DC/DC Regulator PDF資料下載
參數(shù)資料
| 型號： | LTC3548EMSE |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Dual Synchronous,400mA/800mA, 2.25MHz Step-Down DC/DC Regulator |
| 中文描述： | 1.6 A SWITCHING REGULATOR, 2700 kHz SWITCHING FREQ-MAX, PDSO10 |
| 封裝： | PLASTIC, MSOP-10 |
| 文件頁數(shù)： | 7/16頁 |
| 文件大?。?/td> | 239K |
| 代理商： | LTC3548EMSE |
LTC3548
7
3548f
decrease causes the error amplifier to increase the I
TH
voltage until the average inductor current matches the new
load current.
The main control loop is shut down by pulling the RUN pin
to ground.
Low Current Operation
By selecting MODE/SYNC (pin 6), two modes are available
to control the operation of the LTC3548 at low currents.
Both modes automatically switch from continuous opera-
tion to the selected mode when the load current is low.
To optimize efficiency, the Burst Mode operation can be
selected. When the load is relatively light, the LTC3548
automatically switches into Burst Mode operation, in
which the PMOS switch operates intermittently based on
load demand with a fixed peak inductor current. By run-
ning cycles periodically, the switching losses which are
dominated by the gate charge losses of the power MOSFETs
are minimized. The main control loop is interrupted when
the output voltage reaches the desired regulated value. A
voltage comparator trips when I
TH
is below 0.35V, shut-
ting off the switch and reducing the power. The output
capacitor and the inductor supply the power to the load
until I
TH
exceeds 0.65V, turning on the switch and the main
control loop which starts another cycle.
For lower ripple noise at low currents, the pulse skipping
mode can be used. In this mode, the LTC3548 continues
to switch at a constant frequency down to very low
currents, where it will begin skipping pulses. The effi-
ciency in pulse skip mode can be improved slightly by
connecting the SW node to the MODE/SYNC input which
reduces the clock frequency by approximately 30%.
Dropout Operation
When the input supply voltage decreases toward the
output voltage, the duty cycle increases to 100% which is
the dropout condition. In dropout, the PMOS switch is
turned on continuously with the output voltage being
equal to the input voltage minus the voltage drops across
the internal p-channel MOSFET and the inductor.
An important design consideration is that the R
DS(ON)
of
the P-channel switch increases with decreasing input
supply voltage (See Typical Performance Characteristics).
Therefore, the user should calculate the power dissipation
when the LTC3548 is used at 100% duty cycle with low
input voltage (See Thermal Considerations in the Applica-
tions Information Section).
Low Supply Operation
To prevent unstable operation, the LTC3548 incorporates
an Under-Voltage Lockout circuit which shuts down the
part when the input voltage drops below about 1.65V.
OPERATIOU
APPLICATIOU
A general LTC3548 application circuit is shown in
Figure 2. External component selection is driven by the
load requirement, and begins with the selection of the
inductor L. Once the inductor is chosen, C
IN
and C
OUT
can
be selected.
Inductor Selection
Although the inductor does not influence the operating
frequency, the inductor value has a direct effect on ripple
current. The inductor ripple current
I
L
decreases with
higher inductance and increases with higher V
IN
or V
OUT
:
W
U
U
=
I
V
f
O
L
V
V
L
OUT
OUT
IN
–
1
Accepting larger values of
I
L
allows the use of low
inductances, but results in higher output voltage ripple,
greater core losses, and lower output current capability.
A reasonable starting point for setting ripple current is
I
L
= 0.3 I
OUT(MAX)
, where I
OUT(MAX)
is 800mA for
channel 1 and 400mA for channel 2. The largest ripple
current
I
L
occurs at the maximum input voltage. To
guarantee that the ripple current stays below a specified
maximum, the inductor value should be chosen according
to the following equation:
L
V
f
I
V
V
OUT
O
L
OUT
IN MAX
(
=
–
)
1
The inductor value will also have an effect on Burst Mode
operation. The transition from low current operation
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC3701EGN | 2-Phase, Low Input Voltage, Dual Step-Down DC/DC Controller |
| LTC3701 | 16-Bit Universal Bus Driver With 3-State Outputs 48-SSOP -40 to 85 |
| LTC3708 | No RSENSE Low EMI, Synchronous DC/DC Controller with Output Tracking |
| LTC3736 | CTV 5C 5#20 SKT PLUG |
| LTC3736EGN | Dual 2-Phase, No RSENSE Synchronous Controller with Output Tracking |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC3548EMSE#PBF | 功能描述:IC REG BUCK SYNC ADJ DL 10MSOP 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 |
| LTC3548EMSE#TRPBF | 功能描述:IC REG BUCK SYNC ADJ DL 10MSOP 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 |
| LTC3548EMSE-PBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Dual Synchronous, 400mA/800mA, 2.25MHz Step-Down DC/DC Regulator |
| LTC3548EMSE-TRPBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Dual Synchronous, 400mA/800mA, 2.25MHz Step-Down DC/DC Regulator |
| LTC3548IDD | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Dual Synchronous, 400mA/800mA, 2.25MHz |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。