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参数资料
| 型号： | DC1669A |
| 厂商： | Linear Technology |
| 文件页数： | 12/32页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL LTM4627 |
| 软件下载： | LTM4627 Spice Model |
| 设计资源： | LTM4627 Gerber Files DC1669A Design Files |
| 标准包装： | 1 |
| 系列： | LTM®, uModule® |
| 主要目的： | DC/DC，步升 |
| 输出及类型： | 1，非隔离 |
| 输出电压： | 1V，1.2V，1.5V，1.8V，2.5V，3.3V |
| 电流 - 输出： | 15A |
| 输入电压： | 4.5 ~ 20 V |
| 稳压器拓扑结构： | 降压 |
| 频率 - 开关： | 500kHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | LTM4627 |
| 相关产品： | LTM4627IV#PBF-ND - IC UMODULE DC/DC 15A 133LGA LTM4627EV#PBF-ND - IC UMODULE DC/DC 15A 133LGA |
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LTM4627
APPLICATIONS INFORMATION
Output Capacitors
The LTM4627 is designed for low output voltage ripple
noise. The bulk output capacitors defined as C OUT are
chosen with low enough effective series resistance (ESR)
to meet the output voltage ripple and transient require-
ments. C OUT can be a low ESR tantalum capacitor, low
ESR Polymer capacitor or ceramic capacitors. The typical
output capacitance range is from 200μF to 800μF. Additional
output filtering may be required by the system designer
if further reduction of output ripple or dynamic transient
spikes is required. Table 4 shows a matrix of different output
voltages and output capacitors to minimize the voltage
droop and overshoot during a 7.5A/μs transient. The table
optimizes total equivalent ESR and total bulk capacitance
to optimize the transient performance. Stability criteria
are considered in the Table 4 matrix, and LTpowerCAD is
available for stability analysis. Multiphase operation will
reduce effective output ripple as a function of the number of
phases. Application Note 77 discusses this noise reduction
versus output ripple current cancellation, but the output
capacitance should be considered carefully as a function
of stability and transient response. LTpowerCAD can be
used to calculate the output ripple reduction as the number
of implemented phases increases by N times.
Burst Mode Operation
The LTM4627 is capable of Burst Mode operation in which
the power MOSFETs operate intermittently based on load
demand, thus saving quiescent current. For applications
where maximizing the efficiency at very light loads is a
high priority, Burst Mode operation should be applied. To
enable Burst Mode operation, simply float the MODE_PLLIN
pin. During Burst Mode operation, the peak current of the
inductor is set to approximately 30% of the maximum peak
current value in normal operation even though the voltage
at the COMP pin indicates a lower value. The voltage at the
COMP pin drops when the inductor’s average current is
greater than the load requirement. As the COMP voltage
drops below 0.5V, the burst comparator trips, causing
the internal sleep line to go high and turn off both power
MOSFETs.
In sleep mode, the internal circuitry is partially turned
off, reducing the quiescent current. The load current is
now being supplied from the output capacitors. When the
output voltage drops, causing COMP to rise, the internal
sleep line goes low, and the LTM4627 resumes normal
operation. The next oscillator cycle will turn on the top
power MOSFET and the switching cycle repeats.
Pulse-Skipping Mode Operation
In applications where low output ripple and high effi-
ciency at intermediate currents are desired, pulse-skipping
mode should be used. Pulse-skipping operation allows
the LTM4627 to skip cycles at low output loads, thus
increasing efficiency by reducing switching loss. Tying
the MODE_PLLIN pin to INTV CC enables pulse-skipping
operation. With pulse-skipping mode at light load, the
internal current comparator may remain tripped for several
cycles, thus skipping operation cycles. This mode has
lower ripple than Burst Mode operation and maintains a
higher frequency operation than Burst Mode operation.
Forced Continuous Operation
In applications where fixed frequency operation is more
critical than low current efficiency, and where the lowest
output ripple is desired, forced continuous operation
should be used. Forced continuous operation can be
enabled by tying the MODE_PLLIN pin to ground. In this
mode, inductor current is allowed to reverse during low
output loads, the COMP voltage is in control of the current
comparator threshold throughout, and the top MOSFET
always turns on with each oscillator pulse. During start-up,
forced continuous mode is disabled and inductor current
is prevented from reversing until the LTM4627’s output
voltage is in regulation.
4627fc
12
For more information www.linear.com/LTM4627
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相关代理商/技术参数 |
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| DC1669B | 制造商:Linear Technology 功能描述:LTM4627EV Demo Board 20V, 15A DC/DC 制造商:Linear Technology 功能描述:LTM4627EV Demo Board 20V, 15A DC/DC Module Regulator |
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| DC16-73LF | 功能描述:信号调节 .3-2.7GHz Coupling 15.6dB and 14.8dB RoHS:否 制造商:EPCOS 产品:Duplexers 频率:782 MHz, 751 MHz 频率范围: 电压额定值: 带宽: 阻抗:50 Ohms 端接类型:SMD/SMT 封装 / 箱体:2.5 mm x 2 mm 工作温度范围:- 30 C to + 85 C 封装:Reel |
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| DC1676A | 制造商:Linear Technology 功能描述:BOARD DEMO LTC4359 制造商:Linear Technology 功能描述:DEMO BOARD, LTC4359, IDEAL DIODE CONTROLLER; Silicon Manufacturer:Linear Technology; Silicon Core Number:LTC4359; Kit Application Type:Power Management; Application Sub Type:Ideal Diode; Kit Contents:Demo Board LTC4359 |
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