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參數(shù)資料
| 型號(hào)： | CS5203-1GT3 |
| 廠商： | ZF Electronics Corporation |
| 英文描述： | 3A Adjustable Linear Regulator |
| 中文描述： | 第3A可調(diào)線性穩(wěn)壓器 |
| 文件頁(yè)數(shù)： | 5/8頁(yè) |
| 文件大?。?/td> | 165K |
| 代理商： | CS5203-1GT3 |
5
C
Applications Information
The CS5203-1 linear regulator provides adjustable volt-
ages at currents up to 3A. The regulator is protected
against overcurrent conditions and includes thermal
shutdown.
The CS5203-1 has a composite PNP-NPN output transistor
and requires an output capacitor for stability. A detailed
procedure for selecting this capacitor is included in the
Stability Considerations section.
The CS5203-1 has an output voltage range of 1.25V to 5.5V.
An external resistor divider sets the output voltage as
shown in Figure 1. The regulator maintains a fixed 1.25V
(typical) reference between the output pin and the adjust
pin.
A resistor divider network R1 and R2 causes a fixed cur-
rent to flow to ground. This current creates a voltage
across R2 that adds to the 1.25V across R1 and sets the
overall output voltage. The adjust pin current (typically
50μA) also flows through R2 and adds a small error that
should be taken into account if precise adjustment of V
OUT
is necessary.
The output voltage is set according to the formula:
V
OUT
= V
REF
′
(
)
+ I
Adj
′
R2
The term I
Adj
′
R2 represents the error added by the adjust
pin current.
R1 is chosen so that the minimum load current is at least
2mA. R1 and R2 should be the same type, e.g. metal film
for best tracking over temperature. While not required, a
bypass capacitor between the adjust pin and ground will
improve ripple rejection and transient response. A 0.1μF
tantalum capacitor is recommended for òfirst cutó design.
Type and value may then be varied to optimize perfor-
mance vs. price.
Figure 1. Resistor divider scheme.
The 5203-1 linear regulator has an absolute maximum
specification of 7V for the voltage difference between V
IN
and V
OUT
. However, the IC may be used to regulate volt-
ages in excess of 7V. The main considerations in such a
design are power-up and short circuit capability.
In most applications, ramp-up of the power supply to V
IN
is fairly slow, typically on the order of several tens of mil-
liseconds, while the regulator responds in less than one
microsecond. In this case, the linear regulator begins
charging the load as soon as the V
IN
to V
OUT
differential is
large enough that the pass transistor conducts current. The
load at this point is essentially at ground, and the supply
voltage is on the order of several hundred millivolts, with
the result that the pass transistor is in dropout. As the sup-
ply to V
IN
increases, the pass transistor will remain in
dropout, and current is passed to the load until V
OUT
reaches the point at which the IC is in regulation. Further
increase in the supply voltage brings the pass transistor
out of dropout. The result is that the output voltage fol-
lows the power supply ramp-up, staying in dropout until
the regulation point is reached. In this manner, any output
voltage may be regulated. There is no theoretical limit to
the regulated voltage as long as the V
IN
to V
OUT
differen-
tial of 7V is not exceeded.
However, the possibility of destroying the IC in a short
circuit condition is very real for this type of design. Short
circuit conditions will result in the immediate operation of
the pass transistor outside of its safe operating area. Over-
voltage stresses will then cause destruction of the pass
transistor before overcurrent or thermal shutdown circuit-
ry can become active. Additional circuitry may be required
to clamp the V
IN
to V
OUT
differential to less than 7V if fail-
safe operation is required. One possible clamp circuit is
illustrated in figure 2; however, the design of clamp cir-
cuitry must be done on an application by application basis.
Care must be taken to ensure the clamp actually protects
the design. Components used in the clamp design must be
able to withstand the short circuit condition indefinitely
while protecting the IC.
Figure 2. Short Circuit Protection Circuit for High Voltage Application.
The output or compensation capacitor helps determine
three main characteristics of a linear regulator: start-up
delay, load transient response and loop stability.
The capacitor value and type is based on cost, availability,
size and temperature constraints. A tantalum or aluminum
Stability Considerations
V
IN
V
OUT
V
Adj
EXTERNAL SUPPLY
V
OUT
V
OUT
V
IN
CS5203-1
V
IN
Adj
R
1
R
2
C
1
C
Adj
V
OUT
C
2
V
REF
I
Adj
R1 + R2
R1
Adjustable Operation
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| CS5203-3GDP3 | 3A, 3.3V Fixed Linear Regulator |
| CS5203-3GDPR3 | 3A, 3.3V Fixed Linear Regulator |
| CS5203-3 | 3A, 3.3V Fixed Linear Regulator |
| CS5205-5 | 5A Adjustable, and 3.3V and 5V Fixed Linear Regulators |
| CS5205-1 | 5A Adjustable, and 3.3V and 5V Fixed Linear Regulators |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| CS-5203-1T3 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Positive Adjustable Voltage Regulator |
| CS5203-3 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:3.0 A, 3.3 V Fixed Linear Regulator |
| CS5203-3/D | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:3A， 3.3V Fixed Linear Regulator |
| CS-5203-3DP3 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Positive Fixed Voltage Regulator |
| CS5203-3GDP3 | 制造商:CHERRY 制造商全稱:CHERRY 功能描述:3A, 3.3V Fixed Linear Regulator |
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