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| 型号： | FAN2500S33X |
| 厂商： | Fairchild Semiconductor |
| 文件页数： | 10/12页 |
| 文件大小： | 0K |
| 描述： | IC REG LDO 3.3V .1A SOT-23-5 |
| 产品变化通告： | Mold Compound Change 12/Dec/2007 |
| 标准包装： | 1 |
| 稳压器拓扑结构： | 正，固定式 |
| 输出电压： | 3.3V |
| 输入电压： | 最高 6.5V |
| 电压 - 压降（标准）： | 0.1V @ 100mA |
| 稳压器数量： | 1 |
| 电流 - 输出： | 100mA |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | SC-74A，SOT-753 |
| 供应商设备封装： | SOT-23-5 |
| 包装： | 标准包装 |
| 产品目录页面： | 1221 (CN2011-ZH PDF) |
| 其它名称： | FAN2500S33XDKR |
Thermal Protection
FAN2500 can supply high peak output currents of up to 1
A for brief periods. However, this output load causes the
device temperature to exceed maximum ratings due to
power dissipation. During output overload conditions,
when the die temperature exceeds the shutdown limit
temperature of 150°C, onboard thermal protection dis-
ables the output until the temperature drops below this
limit, at which point the output is re-enabled. During a
thermal shutdown situation, the user may assert the
power-down function at the Enable pin, reducing power
consumption to the minimum level I GND · V IN .
Thermal Characteristics
FAN2500 can supply 100 mA at the specified output volt-
age with an operating die (junction) temperature of up to
125°C. Once the power dissipation and thermal resis-
tance is known, the maximum junction temperature of
the device can be calculated. While the power dissipa-
tion is calculated from known electrical parameters, the
thermal resistance is a result of the thermal characteris-
tics of the compact SOT23-5 surface-mount package
and the surrounding PC board copper to which it is
mounted.
The power dissipation is equal to the product of the input
to output voltage differential and the output current, plus
the ground current multiplied by the input voltage, or:
P D = ( V IN – V OUT ) I OUT + V IN I GND
The ground pin current, I GND, can be found in the charts
provided in the Electrical Characteristics section.
The relationship describing the thermal behavior of the
package is:
P D ( max ) = ? ------------------------------- ?
? ?
where T J(max) is the maximum allowable junction temper-
ature of the die, which is 125°C, and T A is the ambient
operating temperature. θ JA is dependent on the sur-
rounding PC board layout and can be empirically
obtained. While the θ JC (junction-to-case) of the SOT23-
5 package is specified at 130°C /W, the θ JA of the mini-
mum PWB footprint is at least 235°C/W. This can be
improved by providing a heat sink of surrounding copper
ground on the PCB.
Depending on the size of the copper area, the resulting
θ JA can range from approximately 180°C/W for one
square inch to nearly 130°C/W for four square inches.
The addition of backside copper with through-holes, stiff-
eners, and other enhancements can reduce this value.
The heat contributed by the dissipation of other devices
nearby must be included in design considerations.
? 2010 Fairchild Semiconductor Corporation
FAN2500 Rev. 1.1.0
10
Once the limiting parameters in these two relationships
have been determined, the design can be modified to
ensure that the device remains within specified operating
conditions at all times.
If overload conditions are not considered, it is possible
for the device to enter a thermal cycling loop, in which
the circuit enters a shutdown condition, cools, re-
enables, and then again overheats and shuts down
repeatedly due to an unmanaged fault condition.
Operational of Adjustable Version
The adjustable version of the FAN2500 includes an input
pin, ADJ, which allows the user to select an output volt-
age ranging from 1.8 V to near V IN , using an external
resistor divider. The voltage V ADJ presented to the ADJ
pin is fed to the onboard error amplifier, which adjusts
the output voltage until V ADJ is equal to the onboard
bandgap reference voltage of 1.32 V (typ). The equation
is:
The total value of the resistor chain should not exceed
250 k ? total to keep the error amplifier biased during no-
load conditions. Programming output voltages very near
V IN need to allow for the magnitude and variation of the
dropout voltage V DO over load, supply, and temperature
variations. Note that the low-leakage MOSFET input to
the CMOS error amplifier induces no bias current error to
the calculation.
General PCB Layout Considerations
To achieve the full performance of the device, careful cir-
cuit layout and grounding technique must be observed.
Establishing a small local ground, to which the GND pin,
the output, and bypass capacitors are connected; is rec-
ommended. The input capacitor should be grounded to
the main ground plane. The quiet local ground is routed
back to the main ground plane using feed-through vias.
In general, the high-frequency compensation compo-
nents (input, bypass, and output capacitors) should be
located as close to the device as possible. The proxim-
ity of the output capacitor is especially important to
achieve optimal noise compensation from the onboard
error amplifier, especially during high load conditions. A
large copper area in the local ground provides the heat
sinking discussed above when high power dissipation
significantly increases the temperature of the device.
Component-side copper provides significantly better
thermal performance for this surface-mount device, com-
pared to that obtained when using only copper planes on
the underside.
www.fairchildsemi.com
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相关代理商/技术参数 |
参数描述 |
|---|---|
| FAN2500S33X_Q | 功能描述:低压差稳压器 - LDO 100 mA CMOS Dropout RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20 |
| FAN2500SX | 功能描述:低压差稳压器 - LDO 100 mA CMOS Dropout RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20 |
| FAN2500SX_Q | 功能描述:低压差稳压器 - LDO 100 mA CMOS Dropout RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20 |
| FAN2501 | 制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:100 mA CMOS LDO Regulators |
| FAN2501S25 | 制造商:未知厂家 制造商全称:未知厂家 功能描述:VOLT REGULATOR|FIXED|+2.5V|CMOS|TSOP|6PIN|PLASTIC |
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