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参数资料
| 型号： | 750105 |
| 厂商： | Wurth Electronics Inc |
| 文件页数： | 14/24页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL FOR LT3574 |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 1，隔离 |
| 功率 - 输出： | 2.5W |
| 输出电压： | 5V |
| 电流 - 输出： | 500mA（最小值） |
| 输入电压： | 10 ~ 30 V |
| 稳压器拓扑结构： | 回扫 |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | LT3574 |
| 其它名称： | 732-3309 |
LT3574
APPLICATIONS INFORMATION
V IN ( UVLO , RISING ) =
+ 2 . 5 μA ? R 1
V IN ( UVLO , FALLING ) =
SettingtheCurrentLimitResistor
The maximum current limit can be set by placing a resistor
between the R ILIM pin and ground. This provides some
flexibility in picking standard off-the-shelf transformers that
may be rated for less current than the LT3574’s internal
power switch current limit. If the maximum current limit
is needed, use a 10k resistor. For lower current limits, the
following equation sets the approximate current limit:
R ILIM = 65 ? 10 3 ( 0 . 9 A ? I LIM ) + 10 k
The Switch Current Limit vs R ILIM plot in the Typical Per-
formance Characteristics section depicts a more accurate
current limit.
Undervoltage Lockout (UVLO)
The SHDN /UVLO pin is connected to a resistive voltage
divider connected to V IN as shown in Figure 8. The voltage
threshold on the SHDN /UVLO pin for V IN rising is 1.22V.
To introduce hysteresis, the LT3574 draws 2.5μA from the
SHDN /UVLO pin when the pin is below 1.22V. The hysteresis
is therefore user-adjustable and depends on the value of
R1. The UVLO threshold for V IN rising is:
1 . 22 V ? (R1 + R2)
R 2
The UVLO threshold for V IN falling is:
1 . 22 V ? (R1 + R2)
R 2
V IN
SHDN /UVLO
R1
To implement external run/stop control, connect a small
NMOS to the UVLO pin, as shown in Figure 8. Turning the
NMOS on grounds the UVLO pin and prevents the LT3574
from operating, and the part will draw less than a 1μA of
quiescent current.
Minimum Load Requirement
The LT3574 obtains output voltage information through
the transformer while the secondary winding is conducting
current. During this time, the output voltage (multiplied
times the turns ratio) is presented to the primary side of
the transformer. The LT3574 uses this reflected signal to
regulate the output voltage. This means that the LT3574
must turn on every so often to sample the output voltage,
which delivers a small amount of energy to the output.
This sampling places a minimum load requirement on the
output of 1% to 2% of the maximum load.
BIAS Pin Considerations
For applications with an input voltage less than 15V, the
BIAS pin is typically connected directly to the V IN pin. For
input voltages greater than 15V, it is preferred to leave the
BIAS pin separate from the V IN pin. In this condition, the
BIAS pin is regulated with an internal LDO to a voltage of
3V. By keeping the BIAS pin separate from the input voltage
at high input voltages, the physical size of the capacitors
can be minimized (the BIAS pin can then use a 6.3V or
10V rated capacitor).
LT3574
GND
R2
3574 F08
RUN/STOP
CONTROL
(OPTIONAL)
Figure 8. Undervoltage Lockout (UVLO)
3574f
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相关代理商/技术参数 |
参数描述 |
|---|---|
| 75010531 | 制造商:PHILIPS 功能描述:STARTER FLUORESCENT TUBE 70-125W 制造商:Philco/Philips 功能描述:STARTER, FLUORESCENT TUBE, 70-125W 制造商:NXP Semiconductors 功能描述:STARTER, FLUORESCENT TUBE, 70-125W; Accessory Type:Starter; For Use With:Fluorescent; SVHC:No SVHC (18-Jun-2012); Power Rating:125W; Supply Voltage:240V ;RoHS Compliant: Yes |
| 750-105-R220/270 | 制造商:CTS Corporation 功能描述: |
| 750-105-R220/330 | 制造商: 功能描述: 制造商:undefined 功能描述: 制造商:CTS Corporation 功能描述:S10-R220/330 |
| 750106 | 功能描述:BOARD EVAL FOR LT3575 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 标准包装:1 系列:- 主要目的:DC/DC，步降 输出及类型:1，非隔离 功率 - 输出:- 输出电压:3.3V 电流 - 输出:3A 输入电压:4.5 V ~ 28 V 稳压器拓扑结构:降压 频率 - 开关:250kHz 板类型:完全填充 已供物品:板 已用 IC / 零件:L7981 其它名称:497-12113STEVAL-ISA094V1-ND |
| 750-106 | 制造商:GLENAIR 制造商全称:Glenair, Inc. 功能描述:Pre-Terminated Assemblies |
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