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| 型号： | LTM8025MPV#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 13/22页 |
| 文件大小： | 0K |
| 描述： | IC CONVERTER BUCK 3A ADJ 70LGA |
| 产品培训模块： | LTM8025 - 36VIN, 3A Step Down Regulator Wide Temperature DC/DC Converter µModules High Voltage µModule DC/DC Regulators Power Module vs. Discrete DC to DC |
| 软件下载： | LTM8025 Spice Model |
| 产品目录绘图： | LTM Series_15x15x4.3 |
| 设计资源： | DC1379A Design Files LTM8025MPV#PBF Footprint.bxl |
| 特色产品： | LTM8025 Series μModule Products |
| 标准包装： | 170 |
| 系列： | µModule® |
| 类型： | 非隔离（POL） |
| 输出数： | 1 |
| 电压 - 输入（最小）： | 3.6V |
| 电压 - 输入（最大）： | 36V |
| Voltage - Output 1： | 0.8 ~ 24 V |
| 电流 - 输出（最大）： | 3A |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 70-LGA |
| 尺寸/尺寸： | 0.59" L x 0.35" W x 0.17" H（15.0mm x 9.0mm x 4.3mm） |
| 包装： | 托盘 |
| 工作温度： | -55°C ~ 125°C |
| 产品目录页面： | 2711 (CN2011-ZH PDF) |
| 配用： | DC1379A-ND - BOARD EVAL LTM8025 |
LTM8025
APPLICATIONS INFORMATION
GND
whether the RUN/SS is used. As shown in the Typical
Performance Characteristics section, the minimum input
voltage to run a 3.3V output at light load is only about 3.6V,
but, if the RUN/SS is pulled up to V IN , it takes 5.5V IN to
start. If the LTM8025 is enabled with the RUN/SS pin, the
minimum voltage to start at light loads is lower, about 4.3V.
Similar curves detailing this behavior of the LTM8025 for
other outputs are also included in the Typical Performance
Characteristics section.
Soft-Start
The RUN/SS pin can be used to soft-start the LTM8025,
reducing the maximum input current during start-up.
The RUN/SS pin is driven through an external RC filter to
create a voltage ramp at this pin, as shown in Figure 1.
By choosing an appropriate RC time constant, the peak
start-up current can be reduced to the current that is re-
quired to regulate the output, with no overshoot. Choose
the value of the resistor so that it can supply at least 20μA
when the RUN/SS pin reaches 2.5V.
Frequency Foldback
RUN
15k
RUN/SS
0.22μF
8025 F01
Figure 1. To Soft-Start the LTM8025, Add a Resistor and
Capacitor to the RUN/SS Pin
The LTM8025 is equipped with frequency foldback which
acts to reduce the thermal and energy stress on the internal
power elements during a short circuit or output overload
condition. If the LTM8025 detects that the output has fallen
out of regulation, the switching frequency is reduced as a
function of how far the output is below the target voltage.
This in turn limits the amount of energy that can be delivered
to the load under fault. During the start-up time, frequency
foldback is also active to limit the energy delivered to the
potentially large output capacitance of the load.
Synchronization
The internal oscillator of the LTM8025 can be synchronized
by applying an external 250kHz to 2MHz clock to the SYNC
pin. Do not leave this pin floating. When synchronizing
the LTM8025, select an R T resistor value that corresponds
to an operating frequency 20% lower than the intended
synchronization frequency (see the Frequency Selection
section).
In addition to synchronization, the SYNC pin controls Burst
Mode behavior. If the SYNC pin is driven by an external
clock, or pulled up above 0.7V, the LTM8025 will not en-
ter Burst Mode operation, but will instead skip pulses to
maintain regulation instead.
Shorted Input Protection
Care needs to be taken in systems where the output will be
held high when the input to the LTM8025 is absent. This
may occur in battery charging applications or in battery
backup systems where a battery or some other supply is
diode ORed with the LTM8025’s output. If the V IN pin is
allowed to float and the SHDN pin is held high (either by a
logic signal or because it is tied to V IN ), then the LTM8025’s
internal circuitry will pull its quiescent current through
its internal power switch. This is fine if your system can
tolerate a few milliamps in this state. If you ground the
RUN/SS pin, the input current will drop to essentially zero.
However, if the V IN pin is grounded while the output is
held high, then parasitic diodes inside the LTM8025 can
pull large currents from the output through the V IN pin.
Figure 2 shows a circuit that will run only when the input
voltage is present and that protects against a shorted or
reversed input.
PCB Layout
Most of the headaches associated with PCB layout have
been alleviated or even eliminated by the high level of
integration of the LTM8025. The LTM8025 is neverthe-
less a switching power supply, and care must be taken to
minimize EMI and ensure proper operation. Even with the
high level of integration, you may fail to achieve specified
operation with a haphazard or poor layout. See Figure 3
for a suggested layout. Ensure that the grounding and
heatsinking are acceptable.
8025fc
For more information www.linear.com/LTM8025
13
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTM8025MPY#PBF | 制造商:Linear Technology 功能描述:DC/DC CONVERTER 0.8-24V 72W 制造商:Linear Technology 功能描述:BUCK UMODULE 36VIN 3A BGA- 制造商:Linear Technology 功能描述:BUCK, UMODULE, 36VIN, 3A, BGA-70 制造商:Linear Technology 功能描述:DC-DC REGULATOR, BUCK, ADJ, BGA-70, Primary Input Voltage:36V, No. of Outputs:1, Output Current:3A, No. of Pins:70, Operating Temperature Min:-55C, Operating Temperature Max:125C, MSL:MSL 3 - 168 hours, Package / Case:70-BGA , RoHS Compliant: Yes |
| LTM8026 | 制造商:LINER 制造商全称:Linear Technology 功能描述:36VIN, 5A, 2-Quadrant CVCC Step-Down |
| LTM8026_1208 | 制造商:LINER 制造商全称:Linear Technology 功能描述:36VIN, 5A CVCC Step-Down ??Module Regulator |
| LTM8026EV#PBF | 功能描述:IC UMODULE REGULATOR 36VIN 5A RoHS:是 类别:电源 - 板载 >> DC DC Converters 系列:µModule® 设计资源:VI-200, VI-J00 Design Guide, Appl Manual 标准包装:1 系列:* 类型:隔离 输出数:1 电压 - 输入（最小）:66V 电压 - 输入（最大）:160V Voltage - Output 1:12V Voltage - Output 2:- Voltage - Output 3:- 电流 - 输出（最大）:* 电源（瓦） - 制造商系列:50W 电压 - 隔离:* 特点:* 安装类型:通孔 封装/外壳:9-FinMod 尺寸/尺寸:4.60" L x 1.86" W x 0.79" H（116.8mm x 47.2mm x 20.1mm） 包装:散装 工作温度:-25°C ~ 85°C 效率:* 电源（瓦特）- 最大:* |
| LTM8026EV#PBF | 制造商:Linear Technology 功能描述:DC-DC CONV 1MHZ LGA-81 |
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