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参数资料
| 型号： | ADP171-EVALZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 14/20页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL ADP171 1V |
| 标准包装： | 1 |
| 每 IC 通道数： | 1 - 单 |
| 输出电压： | 1V |
| 电流 - 输出： | 300mA |
| 输入电压： | 1.6 ~ 3.6V |
| 稳压器类型： | 正，可调式 |
| 工作温度： | -40°C ~ 125°C |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | ADP171 |
| 其它名称： | ADP171EVALZ ADP171EVALZ-ND |
ADP170/ADP171
CURRENT LIMIT AND THERMAL OVERLOAD
PROTECTION
Data Sheet
The junction temperature of the ADP170 / ADP171 can be
calculated from the following equation:
The ADP170 / ADP171 are protected against damage due to
excessive power dissipation by current and thermal overload
protection circuits. The ADP170 / ADP171 are designed to limit
the current when the output load reaches 450 mA (typical).
When the output load exceeds 450 mA, the output voltage is
reduced to maintain a constant current limit.
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)
Thermal overload protection is included, which limits the junction
temperature to a maximum of 150°C (typical). Under extreme
conditions (that is, high ambient temperature and power dissip-
ation), when the junction temperature starts to rise above 150°C,
the output is turned off, reducing the output current to 0. When
the junction temperature drops below 135°C, the output is turned
on again and output current is restored to its nominal value.
Consider the case where a hard short from VOUT to GND occurs.
At first, the ADP170 / ADP171 will limit the current so that only
450 mA is conducted into the short. If self-heating of the junction
is great enough to cause its temperature to rise above 150°C,
thermal shutdown will activate, turning off the output and
reducing the output current to 0. As the junction temperature
cools and drops below 135°C, the output turns on and conducts
450 mA into the short, again causing the junction temperature
to rise above 150°C. This thermal oscillation between 135°C
and 150°C causes a current oscillation between 450 mA and 0 mA,
which continues as long as the short remains at the output.
where:
I LOAD is the load current.
I GND is the ground current.
V IN and V OUT are input and output voltages, respectively.
Power dissipation due to ground current is quite small and can
be ignored. Therefore, the junction temperature equation
simplifies to the following:
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 that the junction temperature does not rise above 125°C.
for different ambient temperatures, load currents, V IN to V OUT
differentials, and areas of PCB copper.
140
T J MAX
120
Current and thermal limit protections are intended to protect
the device against accidental overload conditions.
THERMAL CONSIDERATIONS
100
80
I LOAD = 300mA
I LOAD = 150mA
To guarantee reliable operation, the junction temperature of the
60
I LOAD = 100mA
temperature stays below this maximum value, the user needs to
40
I LOAD = 25mA
I LOAD = 1mA
be aware of the parameters that contribute to junction temperature
changes. These parameters include ambient temperature, power
dissipation in the power device, and thermal resistances between
the junction and ambient air (θ JA ). The θ JA number is dependent
on the package assembly compounds used and the amount of
copper to which the GND pin of the package is soldered on the
PCB. Table 6 shows typical θ JA values of the 5-lead TSOT package
for various PCB copper sizes.
20
0
0.5
140
120
I LOAD = 10mA
1.0 1.5 2.0 2.5
V OUT – V IN (V)
Figure 33. 500 mm 2 of PCB Copper, T A = 25°C
T J MAX
3.0
Table 6. Typical θ JA Values
Copper Size (mm 2 )
50
100
300
500
θ JA (°C/W)
170
152
146
134
131
100
80
60
40
I LOAD = 300mA
I LOAD = 150mA
I LOAD = 100mA
I LOAD = 25mA
1
Device soldered to minimum size pin traces.
20
I LOAD = 1 m A
I LOAD = 10mA
0
0.5
1.0
1.5
2.0
2.5
3.0
V OUT – V IN (V)
Figure 34. 100 mm 2 of PCB Copper, T A = 25°C
Rev. C | Page 14 of 20
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ADP172 | 制造商:AD 制造商全称:Analog Devices 功能描述:300 mA, Low Quiescent Current, CMOS Linear Regulator |
| ADP172_10 | 制造商:AD 制造商全称:Analog Devices 功能描述:300 mA, Low Quiescent Current, CMOS Linear Regulator |
| ADP172_101 | 制造商:AD 制造商全称:Analog Devices 功能描述:300 mA, Low Quiescent Current CMOS Linear Regulator |
| ADP1720 | 制造商:AD 制造商全称:Analog Devices 功能描述:50mA High-Voltage Micro-power LDO in MSOP |
| ADP1720-3.3 | 制造商:AD 制造商全称:Analog Devices 功能描述:Complete Closed-Loop Precision Analog Microcontroller Thermocouple |
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