參數(shù)資料
型號: MC78M00
廠商: ON SEMICONDUCTOR
英文描述: 500 mA Positive Voltage Regulators(500 mA正向穩(wěn)壓器)
中文描述: 500毫安正電壓穩(wěn)壓器(500 mA的正向穩(wěn)壓器)
文件頁數(shù): 9/16頁
文件大?。?/td> 178K
代理商: MC78M00
MC78M00, MC78M00A Series
http://onsemi.com
9
APPLICATIONS INFORMATION
Design Considerations
The MC78M00/MC78M00A Series of fixed voltage
regulators are designed with Thermal Overload Protection
that shuts down the circuit when subjected to an excessive
power overload condition, Internal Short Circuit Protection
that limits the maximum current the circuit will pass, and
Output Transistor Safe-Area Compensation that reduces the
output short circuit current as the voltage across the pass
transistor is increased.
In many low current applications, compensation
capacitors are not required. However, it is recommended
that the regulator input be bypassed with a capacitor if the
regulator is connected to the power supply filter with long
wire lengths, or if the output load capacitance is large. An
input bypass capacitor should be selected to provide good
high frequency characteristics to insure stable operation
under all load conditions. A 0.33 F or larger tantalum,
mylar, or other capacitor having low internal impedance at
high frequencies should be chosen. The bypass capacitor
should be mounted with the shortest possible leads directly
across the regulator's input terminals. Normally good
construction techniques should be used to minimize ground
loops and lead resistance drops since the regulator has no
external sense lead.
The addition of an operational amplifier allows adjustment to higher
or intermediate values while retaining regulation characteristics.
The minimum voltage obtainable with this arrangement is 2.0 V
greater than the regulator voltage.
Input
MC78M05C
Output
0.33 F
10 k
MC1741
7
6
4
1.0 k
0.1 F
3
2
The MC78M00 series can be current boosted with a PNP
transistor. The MJ2955 provides current to 5.0 A. Resistor R in
conjunction with the V
BE
of the PNP determines when the pass
transistor begins conducting; this circuit is not short circuit
proof. Input-output differential voltage minimum is increased
by V
BE
of the pass transistor.
XX = 2 digits of type number indicating voltage.
MC78MXXC
Input
Output
R
1.0 F
MJ2955 or Equiv.
1.0 F
The circuit of Figure 12 can be modified to provide supply protection
against short circuits by adding a short circuit sense resistor, R
sc
,
and an additional PNP transistor. The current sensing PNP must be
able to handle the short circuit current of the three-terminal
regulator .Therefore, a 4.0 A plastic power transistor is specified.
XX = 2 digits of type number indicating voltage.
1.0 F
MC78MXXC
MJ2955
or Equiv.
Input
Output
R
SC
R
2N6049
or Equiv.
V
O
, 7.0 V to 20 V
V
in
-V
out
2.0 V
+
Figure 10. Current Regulator
The MC78M00 regulators can also be used as a current source
when connected as above. In order to minimize dissipation the
MC78M05C is chosen in this application. Resistor R determines
the current as follows:
For example, a 500 mA current source would require R to be a
10
, 10 W resistor and the output voltage compliance would be
the input voltage less 7.0 V.
I
O
=
5.0 V
R
+ I
IB
I
IB
= 1.5 mA over line and load changes.
Input
0.33 F
R
I
O
MC78M05C
Constant
Current to
Grounded
Load
Figure 11. Adjustable Output Regulator
Figure 12. Current Boost Regulator
Figure 13. Current Boost with
Short Circuit Protection
相關(guān)PDF資料
PDF描述
MC78M06 500 mA Positive Voltage Regulators
MC78M08 500mA, 8V, Positive Voltage Regulator(三端中電流正固定電壓穩(wěn)壓器)
MC78M09 500mA, 9V, Positive Voltage Regulator(三端中電流正固定電壓穩(wěn)壓器)
MC78M12 500 mA Positive Voltage Regulators
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC78M05ABDT 功能描述:線性穩(wěn)壓器 - 標(biāo)準(zhǔn) 5V 500mA Positive RoHS:否 制造商:STMicroelectronics 輸出類型: 極性: 輸出電壓:1.8 V 輸出電流:150 mA 負(fù)載調(diào)節(jié): 最大輸入電壓:5.5 V 線路調(diào)整率: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOT-323-5L
MC78M05ABDTG 功能描述:線性穩(wěn)壓器 - 標(biāo)準(zhǔn) 5V 500mA Positive RoHS:否 制造商:STMicroelectronics 輸出類型: 極性: 輸出電壓:1.8 V 輸出電流:150 mA 負(fù)載調(diào)節(jié): 最大輸入電壓:5.5 V 線路調(diào)整率: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOT-323-5L
MC78M05ABDTG 制造商:ON Semiconductor 功能描述:IC, LDO VOLT REG, 5V, 0.5A, D-PAK-3
MC78M05ABDTRK 功能描述:線性穩(wěn)壓器 - 標(biāo)準(zhǔn) 5V 500mA Positive RoHS:否 制造商:STMicroelectronics 輸出類型: 極性: 輸出電壓:1.8 V 輸出電流:150 mA 負(fù)載調(diào)節(jié): 最大輸入電壓:5.5 V 線路調(diào)整率: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOT-323-5L
MC78M05ABDTRKG 功能描述:線性穩(wěn)壓器 - 標(biāo)準(zhǔn) 5V 500mA Positive RoHS:否 制造商:STMicroelectronics 輸出類型: 極性: 輸出電壓:1.8 V 輸出電流:150 mA 負(fù)載調(diào)節(jié): 最大輸入電壓:5.5 V 線路調(diào)整率: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOT-323-5L