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参数资料
| 型号： | LEN-1/28-D12 |
| 元件分类： | 电源模块 |
| 英文描述： | 1-OUTPUT 0.25 W DC-DC REG PWR SUPPLY MODULE |
| 封装： | EIGTH BRICK PACKAGE-10 |
| 文件页数： | 5/9页 |
| 文件大小： | 1008K |
| 代理商： | LEN-1/28-D12 |
LEN D12 Models
N O N - I S O L A T E D , 2 8 A E I G H T H B R I C K , D C / D C C O N V E R T E R S
Figure 5.Trim Connections Using Fixed Resistors
Output Overvoltage Protection
The LEN D12 Series output voltage is monitored. If the output voltage rises
to a level, which could be damaging to the load, the internal sensing circuitry
will power down the PWM controller causing the output voltage to decrease.
Following a time-out period the PWM will restart, causing the output voltage
to ramp to its appropriate value. If the fault condition persists, and the output
voltage again climbs to excessive levels, the overvoltage circuitry will initiate
another shutdown cycle. This on/off cycling is referred to as "hiccup" mode.
Output Overcurrent Detection
Overloading the power converter's output for an extended time will invariably
cause internal component temperatures to exceed their maximum ratings
and eventually lead to component failure. High-current-carrying components
such as inductors, FET's and diodes are at the highest risk. LEN D12 Series
DC/DC converters incorporate an output overcurrent detection and shutdown
function that serves to protect both the power converter and its load.
If the output current exceeds it maximum rating by typically 40% (35 Amps) or
if the output voltage drops to less than 98% of it original value, the LEN D12's
internal overcurrent-detection circuitry immediately turns off the converter,
which then goes into a "hiccup" mode. While hiccupping, the converter will
continuously attempt to restart itself, go into overcurrent, and then shut down.
Under these conditions, both the average output current and the average
input current will be kept extremely low. Once the output short is removed, the
converter will automatically restart itself.
Output Voltage Trimming
Allowable trim ranges for models
≥1.8VOUT are ±10%, and for models 1.5VOUT
and lower +10%/–3% (no trim for 0.8V models). Trimming is accomplished
with either a trimpot or a single xed resistor. The trimpot should be con-
nected between +Output and Common with its wiper connected to the Trim
pin as shown in Figure 4 below.
A trimpot can be used to determine the value of a single xed resistor
Figure 4.Trim Connections Using a Trimpot
Note:
Install either a xed
trim-up resistor
or a xed trim-down
resistor depending upon
desired output voltage.
Trim Equations
Note: Resistor values are in k
. Accuracy of adjustment is subject to
tolerances of resistors and factory-adjusted, initial output accuracy.
VO = desired output voltage. VO
NOM = nominal output voltage.
5
+INPUT
COMMON
ON/OFF
CONTROL
2.5V
+
–
5.6k
20k
Figure 3. Driving The Power-Up With An External Pull-up Resistor
External Input Open: On/Off pin High = DC/DC converter Off
External Input Low:
On/Off pin Low = DC/DC converter On
which can then be connected, as shown in Figure 5, between the Trim pin
and +Output to trim down the output voltage, or between the Trim pin and
Common to trim up the output voltage. Fixed resistors should have absolute
TCR’s less than 100ppm/
°C to ensure stability.
The equations below can be used as starting points for selecting specic trim-
resistor values. Recall, untrimmed devices are guaranteed to be
±1% accurate.
Adjustment beyond the specied adjustment range is not recommended.
Power-up sequencing
If a controlled start-up of one or more LEN D12 Series DC/DC converters
is required, or if several output voltages need to be powered-up in a given
sequence, the On/Off control pin can be pulled high to +VIN with an external
5.6k
restistor. While input voltage and/or other converters are ramping up,
the control pin is pulled high and the converter remains disabled. To enable
the output voltage, the control pin needs to be pulled low in the conguration
shown in Figure 3.
Note: LEN-0.8/28-D12 is not trimmable.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LEN-2.5/28-D12 | 功能描述:DC/DC转换器 70W 12V to 2.5V 28A RoHS:否 制造商:Murata 产品: 输出功率: 输入电压范围:3.6 V to 5.5 V 输入电压（标称）: 输出端数量:1 输出电压（通道 1）:3.3 V 输出电流（通道 1）:600 mA 输出电压（通道 2）: 输出电流（通道 2）: 安装风格:SMD/SMT 封装 / 箱体尺寸: |
| LEN-2.5/28-D12B-C | 功能描述:DC/DC转换器 70W 12V to 2.5V 28A RoHS:否 制造商:Murata 产品: 输出功率: 输入电压范围:3.6 V to 5.5 V 输入电压（标称）: 输出端数量:1 输出电压（通道 1）:3.3 V 输出电流（通道 1）:600 mA 输出电压（通道 2）: 输出电流（通道 2）: 安装风格:SMD/SMT 封装 / 箱体尺寸: |
| LEN-2.5/28-D12-C | 功能描述:DC/DC转换器 70W 12V to 2.5V 28A RoHS:否 制造商:Murata 产品: 输出功率: 输入电压范围:3.6 V to 5.5 V 输入电压（标称）: 输出端数量:1 输出电压（通道 1）:3.3 V 输出电流（通道 1）:600 mA 输出电压（通道 2）: 输出电流（通道 2）: 安装风格:SMD/SMT 封装 / 箱体尺寸: |
| LEN-2.5/28-D12H-C | 功能描述:DC/DC转换器 70W 12V to 2.5V 28A HEAT SINK RoHS:否 制造商:Murata 产品: 输出功率: 输入电压范围:3.6 V to 5.5 V 输入电压（标称）: 输出端数量:1 输出电压（通道 1）:3.3 V 输出电流（通道 1）:600 mA 输出电压（通道 2）: 输出电流（通道 2）: 安装风格:SMD/SMT 封装 / 箱体尺寸: |
| LEN-2.5/28-D12M | 制造商:Murata Power Solutions 功能描述:Module DC-DC 1-OUT 2.5V 28A 10-Pin 1/8-Brick |
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