参数资料
型号: LM350T
厂商: ON Semiconductor
文件页数: 7/10页
文件大小: 0K
描述: IC REG LDO ADJ 3A TO220AB
产品变化通告: Product Discontinuation 27/Jun/2007
标准包装: 50
稳压器拓扑结构: 正,可调式
输出电压: 1.2 V ~ 33 V
稳压器数量: 1
电流 - 输出: 3A
工作温度: 0°C ~ 125°C
安装类型: 通孔
封装/外壳: TO-220-3
供应商设备封装: TO-220AB
包装: 管件
其它名称: LM350TOS
LM350
APPLICATIONS INFORMATION
R 1
Basic Circuit Operation
The LM350 is a three?terminal floating regulator. In
operation, the LM350 develops and maintains a nominal
1.25 V reference (V ref ) between its output and adjustment
terminals. This reference voltage is converted to a
programming current (I PROG ) by R 1 (see Figure 19), and
this constant current flows through R 2 to ground. The
regulated output voltage is given by:
R 2
V out = V ref (1 + ) + I Adj R 2
Since the current from the terminal (I Adj ) represents an
error term in the equation, the LM350 was designed to
control I Adj to less than 100 m A and keep it constant. To do
this, all quiescent operating current is returned to the output
terminal. This imposes the requirement for a minimum
load current. If the load current is less than this minimum,
the output voltage will rise.
Since the LM350 is a floating regulator, it is only the
voltage differential across the circuit which is important to
performance, and operation at high voltages with respect to
ground is possible.
External Capacitors
A 0.1 m F disc or 1 m F tantalum input bypass capacitor
(C in ) is recommended to reduce the sensitivity to input line
impedance.
The adjustment terminal may be bypassed to ground to
improve ripple rejection. This capacitor (C Adj ) prevents
ripple from being amplified as the output voltage is
increased. A 10 m F capacitor should improve ripple
rejection about 15 dB at 120 Hz in a 10 V application.
Although the LM350 is stable with no output
capacitance, like any feedback circuit, certain values of
external capacitance can cause excessive ringing. An
output capacitance (C O ) in the form of a 1 m F tantalum or
25 m F aluminum electrolytic capacitor on the output
swamps this effect and insures stability.
Protection Diodes
When external capacitors are used with any IC regulator,
it is sometimes necessary to add protection diodes to
prevent the capacitors from discharging through low
current points into the regulator.
Figure 18 shows the LM350 with the recommended
protection diodes for output voltages in excess of 25 V or
V in
LM350
Adjust
V out
V ref
+
R 1
I PROG
high capacitance values (C O > 25 m F, C Adj > 10 m F). Diode
D 1 prevents C O from discharging thru the IC during an
input short circuit. Diode D 2 protects against capacitor
C Adj discharging through the IC during an output short
circuit. The combination of diodes D 1 and D 2 prevents C Adj
V out
from discharging through the IC during an input short
I Adj
V ref = 1.25 V Typical
R 2
circuit.
D 1
1N4002
Figure 19. Basic Circuit Configuration
V in
LM350
V out
+
D 2
Load Regulation
The LM350 is capable of providing extremely good load
regulation, but a few precautions are needed to obtain
maximum performance. For best performance, the
C in
Adjust
R 2
R 1
C Adj
C O
1N4002
programming resistor (R 1 ) should be connected as close to
the regulator as possible to minimize line drops which
effectively appear in series with the reference, thereby
degrading regulation. The ground end of R 2 can be returned
near the load ground to provide remote ground sensing and
improve load regulation.
http://onsemi.com
7
Figure 20. Voltage Regulator with
Protection Diodes
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相关代理商/技术参数
参数描述
LM350T 制造商:Texas Instruments 功能描述:V REG ADJ +1.2/33V TO-220-3 350
LM350T 制造商:Fairchild Semiconductor Corporation 功能描述:Linear Voltage Regulator IC
LM350T/LB01 制造商:Texas Instruments 功能描述:LDO Regulator Pos 1.2V to 33V 3A 3-Pin(3+Tab) TO-220 Rail
LM350T/LB07 制造商:Texas Instruments 功能描述:LDO Regulator Pos 1.2V to 33V 3A 3-Pin(3+Tab) TO-220 Rail
LM350T/NOPB 功能描述:线性稳压器 - 标准 3-AMP ADJ REG RoHS:否 制造商:STMicroelectronics 输出类型: 极性: 输出电压:1.8 V 输出电流:150 mA 负载调节: 最大输入电压:5.5 V 线路调整率: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOT-323-5L