參數(shù)資料
型號: MC7905A
廠商: ON SEMICONDUCTOR
元件分類: 基準電壓源/電流源
英文描述: 1.0 A Negative Voltage Regulators(1.0 A三端負固定電壓穩(wěn)壓器)
中文描述: 1.0負電壓穩(wěn)壓器(1.0甲三端負固定電壓穩(wěn)壓器)
文件頁數(shù): 9/16頁
文件大小: 157K
代理商: MC7905A
MC7900 Series
http://onsemi.com
9
APPLICATIONS INFORMATION
Design Considerations
The MC7900 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 SafeArea 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
highfrequency 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 capacitor chosen
should have an equivalent series resistance of less than
0.7
. The bypass capacitor should be mounted with the
shortest possible leads directly across the regulators 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. Bypassing the
output is also recommended.
Figure 8. Current Regulator
The MC7905, 5.0 V regulator can be used as a constant current source when
connected as above. The output current is the sum of resistor R current and
quiescent bias current as follows.
The quiescent current for this regulator is typically 4.3 mA. The 5.0V regulator was
chosen to minimize dissipation and to allow the output voltage to operate to within
6.0 V below the input voltage.
I
O
=
5.0 V
+ I
B
20 V
Input
MC7905
10
R
I
O
= 200 mA
V
O
10 V
1.0 F
Gnd
Gnd
+1.0 F
+
R
Figure 9. Current Boost Regulator
(5.0 V @ 4.0 A, with 5.0 A Current Limiting)
When a boost transistor is used, short circuit currents are equal to the sum of the
series pass and regulator limits, which are measured at 3.2 A and 1.8 A respectively
in this case. Series pass limiting is approximately equal to 0.6 V/R
SC
. Operation
beyond this point to the peak current capability of the MC7905C is possible if the
regulator is mounted on a heatsink; otherwise thermal shutdown will occur when
the additional load current is picked up by the regulator.
*Mounted on heatsink.
10 V
Input
0.56
0.56
0.56
MJE200*
or Equiv
5.6
2N3055*
or Equiv
MC7905*
1.0 F
5.0 V
Output
Gnd
Gnd
+
+
1.0 F
10 F+
Figure 10. Operational Amplifier Supply
(
±
15 @ 1.0 A)
The MC7815 and MC7915 positive and negative regulators may be connected as
shown to obtain a dual power supply for operational amplifiers. A clamp diode
should be used at the output of the MC7815 to prevent potential latchup problems
whenever the output of the positive regulator (MC7815) is drawn below ground with
an output current greater than 200 mA.
+20 V
Input
+15 V
Output
0.33 F
1N4001
or Equiv
Gnd
Gnd
1.0 F
+
20 V
Input
15 V
Output
MC7815
MC7915
+
+
+
1.0 F
1.0 F
1.0 F
相關(guān)PDF資料
PDF描述
MC7908 1.0 A Negative Voltage Regulators(1.0 A三端負固定電壓穩(wěn)壓器)
MC7912 1.0 A Negative Voltage Regulators(1.0 A三端負固定電壓穩(wěn)壓器)
MC7915 1.0 A Negative Voltage Regulators(1.0 A三端負固定電壓穩(wěn)壓器)
MC7924 1.0 A Negative Voltage Regulators(1.0 A三端負固定電壓穩(wěn)壓器)
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參數(shù)描述
MC7905ACD2T 功能描述:線性穩(wěn)壓器 - 標(biāo)準 5V 1A Negative 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
MC7905ACD2TG 功能描述:線性穩(wěn)壓器 - 標(biāo)準 5V 1A Negative 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
MC7905ACD2TR4 功能描述:線性穩(wěn)壓器 - 標(biāo)準 5V 1A Negative 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
MC7905ACD2TR4G 功能描述:線性穩(wěn)壓器 - 標(biāo)準 5V 1A Negative 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
MC7905ACT 功能描述:線性穩(wěn)壓器 - 標(biāo)準 3-Term 1A Neg Volt Regulator 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