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参数资料
| 型号： | ADP124RHZ-REDYKIT |
| 厂商： | Analog Devices Inc |
| 文件页数： | 14/20页 |
| 文件大小： | 0K |
| 描述： | REDYKIT 2.8/3.3 ADP124 |
| 标准包装： | 1 |
| 系列： | Redykit™ |
ADP124/ADP125
CURRENT LIMIT AND THERMAL OVERLOAD
PROTECTION
Data Sheet
Table 6. Typical θ JA Values for Specified PCB Copper Sizes
θ JA (°C/W)
The ADP124/ADP125 are protected from damage due to excessive
power dissipation by current and thermal overload protection
circuits. The ADP124/ADP125 are designed to limit the current
when the output load reaches 750 mA (typical). When the output
load exceeds 750 mA, the output voltage is reduced to maintain
a constant current limit.
Thermal overload protection is included, which limits the junction
Copper
Size (mm 2 )
25
100
500
1000
6400
MSOP
108.6
75.5
42.5
34.7
26.1
LFCSP
177.8
138.2
79.8
67.8
53.5
temperature to a maximum of 150°C typical. Under extreme con-
ditions (that is, high ambient temperature and power dissipation),
when the junction temperature starts to rise above 150°C, the
output is turned off, reducing output current to zero. When the
junction temperature cools to less than 135°C, the output is turned
on again and the output current is restored to its nominal value.
Consider the case where a hard short from VOUT to GND occurs.
Table 7. Typical Ψ JB Values
Ψ JB (°C/W)
MSOP LFCSP
31.7 44.1
The junction temperature of the ADP124/ADP125 can be
calculated from the following equation:
At first, the ADP124/ADP125 limit the current so that only 750 mA
is conducted into the short. If self-heating causes the junction
temperature to rise above 150°C, thermal shutdown activates,
turning off the output and reducing the output current to zero.
When the junction temperature cools to less than 135°C, the
output turns on and conducts 750 mA into the short, again
T J = T A + ( P D × θ JA )
where:
T A is the ambient temperature.
P D is the power dissipation in the die, given by
P D = [( V IN ? V OUT ) × I LOAD ] + ( V IN × I GND )
(2)
(3)
causing the junction temperature to rise above 150°C. This
thermal oscillation between 135°C and 150°C results in a current
oscillation between 750 mA and 0 mA that continues as long
as the short remains at the output.
Current and thermal limit protections are intended to protect the
device from damage due to accidental overload conditions. For
reliable operation, the device power dissipation must be externally
limited so that the junction temperature does not exceed 125°C.
THERMAL CONSIDERATIONS
To guarantee reliable operation, the junction temperature of the
ADP124/ADP125 must not exceed 125°C. To ensure that the
junction temperature is less than this maximum value, the user
needs to be aware of the parameters that contribute to junction
temperature changes. These parameters include ambient tem-
perature, power dissipation in the power device, and thermal
resistances between the junction and ambient air (θ JA ). The value
of θ JA is dependent on the package assembly compounds used
and the amount of copper to which the GND pins of the package
are soldered on the PCB. Table 6 shows typical θ JA values of the
shows typical Ψ JB values of the 8-lead MSOP and 8-lead 3 mm ×
3 mm LFCSP package.
where:
I LOAD is the load current.
I GND is the ground current.
V IN and V OUT are input and output voltages, respectively.
The power dissipation due to ground current is quite small and
can be ignored. Therefore, the junction temperature equation
can be simplified as follows:
T J = T A + {[( V IN ? V OUT ) × I LOAD ] × θ JA } (4)
As shown in Equation 4, for a given ambient temperature, input-
to-output voltage differential, and continuous load current, there
exists a minimum copper size requirement for the PCB to ensure
through Figure 41 show junction temperature calculations for
different ambient temperatures, load currents, V IN to V OUT
differentials, and areas of PCB copper.
In cases where the board temperature is known, the thermal
characterization parameter, Ψ JB , can be used to estimate the jun-
ction temperature rise. The maximum junction temperature (T J ) is
calculated from the board temperature (T B ) and power dissipation
(P D ) using the formula
T J = T B + ( P D × Ψ JB ) (5)
Rev. C | Page 14 of 20
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ADP125 | 制造商:AD 制造商全称:Analog Devices 功能描述:5.5 V Input, 500 mA, Low Quiescent Current, CMOS Linear Regulators |
| ADP1250001RHZR | 制造商:Analog Devices 功能描述: |
| ADP1251 | 制造商:未知厂家 制造商全称:未知厂家 功能描述:PRECISION SEMICONDUCTOR PRESSURE SENSOR |
| ADP125ACPZ-R7 | 功能描述:IC REG LDO ADJ .5A 8LFCSP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 系列:- 标准包装:45 系列:- 稳压器拓扑结构:正，固定式 输出电压:5V 输入电压:6 V ~ 30 V 电压 - 压降（标准）:0.47V @ 250mA 稳压器数量:1 电流 - 输出:250mA 电流 - 限制（最小）:- 工作温度:-40°C ~ 125°C 安装类型:通孔 封装/外壳:TO-220-3 供应商设备封装:TO-220-3 包装:管件 产品目录页面:1289 (CN2011-ZH PDF) 其它名称:*LP2954AIT*LP2954AIT/NOPBLP2954AIT |
| ADP125ARHZ | 功能描述:IC REG LDO ADJ .5A 8MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 系列:- 标准包装:3,000 系列:- 稳压器拓扑结构:正，固定式 输出电压:3V 输入电压:最高 5.5V 电压 - 压降（标准）:0.12V @ 150mA 稳压器数量:1 电流 - 输出:150mA（最小值） 电流 - 限制（最小）:220mA 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:SOT-23-5 细型，TSOT-23-5 供应商设备封装:TSOT-23-5 包装:带卷 (TR) 其它名称:ADP160AUJZ-3.0-R7TR |
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