- 您现在的位置：买卖IC网 > PDF目录69007 > LTC3560ES6#TR (LINEAR TECHNOLOGY CORP) 2.1 A SWITCHING REGULATOR, 2700 kHz SWITCHING FREQ-MAX, PDSO6 PDF资料下载
参数资料
| 型号： | LTC3560ES6#TR |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 2.1 A SWITCHING REGULATOR, 2700 kHz SWITCHING FREQ-MAX, PDSO6 |
| 封装： | 1 MM HEIGHT, PLASTIC, MO-193, TSOT-23 |
| 文件页数： | 14/16页 |
| 文件大小： | 323K |
| 代理商： | LTC3560ES6#TR |
7
LTC3560
3560f
OPERATIO
U
When the converter is in Burst Mode operation, the peak
current of the inductor is set to approximately 150mA re-
gardless of the output load. Each burst event can last from
a few cycles at light loads to almost continuously cycling
with short sleep intervals at moderate loads. In between
these burst events, the power MOSFETs and any unneeded
circuitry are turned off, reducing the quiescent current to
16
A. In this sleep state, the load current is being supplied
solely from the output capacitor. As the output voltage
droops, the EA amplifier’s output rises above the sleep
threshold signaling the BURST comparator to trip and turn
the top MOSFET on. This process repeats at a rate that is
dependent on the load demand.
Frequency Synchronization
When the LTC3560 is clocked by an external source, Burst
Mode operation is disabled; the LTC3560 then operates in
PWM pulse-skipping mode. In this mode, when the output
load is very low, current comparator ICOMP may remain
tripped for several cycles and force the main switch to stay
off for the same number of cycles. Increasing the output
load slightly allows constant frequency PWM operation to
resume. This mode exhibits low output ripple as well as
low audio noise and reduced RF interference while provid-
ing reasonable low current efficiency.
Dropout Operation
As the input supply voltage decreases to a value approach-
ing the output voltage, the duty cycle increases toward the
maximum on time. Further reduction of the supply voltage
forces the main switch to remain on for more than one cycle
until it reaches 100% duty cycle. The output voltage will then
be determined by the input voltage minus the voltage drop
across the P-channel MOSFET and the inductor.
Another important detail to remember is that at low input
supply voltages, the RDS(ON) of the P-channel switch
increases (see Typical Performance Characteristics). There-
fore, the user should calculate the power dissipation when
the LTC3560 is used at 100% duty cycle with low input
voltage (See Thermal Considerations in the Applications
Information section).
(Refer to Functional Diagram)
Main Control Loop
The LTC3560 uses a constant frequency, current mode
step-down architecture. Both the main (P-channel MOS-
FET) and synchronous (N-channel MOSFET) switches are
internal. During normal operation, the internal top power
MOSFET is turned on each cycle when the oscillator sets
the RS latch, and turned off when the current comparator,
ICOMP, resets the RS latch. The peak inductor current at
which ICOMP resets the RS latch, is controlled by the output
of error amplifier EA. The VFB pin,describedinthePinFunc-
tions section, allows EA to receive an output feedback
voltage from an external resistive divider. When the load
current increases, it causes a slight decrease in the feed-
back voltage relative to the 0.6V reference, which in turn,
causes the EA amplifier’s output voltage to increase until
the average inductor current matches the new load cur-
rent. While the top MOSFET is off, the bottom MOSFET is
turned on until either the inductor current starts to reverse,
as indicated by the current reversal comparator IRCMP, or
the beginning of the next clock cycle.
The main control loop is shut down by grounding RUN,
resetting the internal soft-start. Re-enabling the main
control loop by pulling RUN high activates the internal
soft-start, which slowly ramps the output voltage over
approximately 0.9ms until it reaches regulation.
Burst Mode Operation
The LTC3560 is capable of Burst Mode operation in which
the internal power MOSFETs operate intermittently based
on load demand. To enable Burst Mode operation, simply
connect the SYNC/MODE pin to GND. To disable Burst
Mode operation and enable PWM pulse skipping mode,
connect the SYNC/MODE pin to VIN or drive it with a logic
high (VMODE > 1.5V). In this mode, the efficiency is lower
at light loads, but becomes comparable to Burst Mode
operation when the output load exceeds 100mA. The
advantage of pulse skipping mode is lower output ripple
and less interference to audio circuitry.
相关PDF资料 |
PDF描述 |
|---|---|
| LTC3560ES6#TRM | 2.1 A SWITCHING REGULATOR, 2700 kHz SWITCHING FREQ-MAX, PDSO6 |
| LTC3605IUF#PBF | 7.5 A SWITCHING REGULATOR, 4000 kHz SWITCHING FREQ-MAX, PQCC24 |
| LTC3605IUF#TRPBF | 7.5 A SWITCHING REGULATOR, 4000 kHz SWITCHING FREQ-MAX, PQCC24 |
| LTC3675EUFF#TRPBF | POWER SUPPLY SUPPORT CKT, PQCC44 |
| LTC3727AIG-1#TR | 3 A SWITCHING CONTROLLER, 580 kHz SWITCHING FREQ-MAX, PDSO28 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3560ES6TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:2.25MHz, 800mA Synchronous Step-Down Regulator in ThinSOT |
| LTC3560IS6#TRMPBF | 功能描述:IC REG BUCK SYNC ADJ TSOT23-6 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:升压（升压） 输出类型:可调式 输出数:1 输出电压:1.24 V ~ 30 V 输入电压:1.5 V ~ 12 V PWM 型:电流模式，混合 频率 - 开关:600kHz 电流 - 输出:500mA 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) 供应商设备封装:8-SOIC |
| LTC3560IS6#TRPBF | 功能描述:IC REG BUCK SYNC ADJ TSOT23-6 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:升压（升压） 输出类型:可调式 输出数:1 输出电压:1.24 V ~ 30 V 输入电压:1.5 V ~ 12 V PWM 型:电流模式，混合 频率 - 开关:600kHz 电流 - 输出:500mA 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) 供应商设备封装:8-SOIC |
| LTC3561 | 制造商:LINER 制造商全称:Linear Technology 功能描述:1A, 4MHz, Synchronous Step-Down DC/DC Converter |
| LTC3561A | 制造商:LINER 制造商全称:Linear Technology 功能描述:1A, 4MHz, Synchronous Step-Down DC/DC Converter |
发布紧急采购，3分钟左右您将得到回复。