CS-5201 Datasheet, PDF (5/6 Pages) First Components International – 1Amp Low Dropout Positive Voltage Regulator

CS-5201 1Amp Low Dropout Positive Voltage Regulator
Output Voltage
The CS5201(adjustable version) develops a 1.25V
reference voltage between the Sense pin and the Adjust
pin (Figure 4). Placing a resistor between these two
terminals causes a constant current to flow though R1
and down thouth R2 to set the output voltage. In general
R1 is chosen so that this current is the specified minimum
load current of 5 mA. The current out of the Adjust pin is
small, typically 50 A and it adds to the current from R1.
For best regulation the top of the resistor divider should
be connected directly to the Sense pin.00000000000000
VCONTROL
+
VPOWER
CONTROL
POWER OUTPUT
+
CS5201 ^SENSE
+
ADJ.
V_REF R1
IADJ
R2
V_OUT=V_{REF(1+R2/R1)+}I_ADJR2
VOUT
Figure 4. Setting Output Voltage
Protection Diodes
In normal operation CS5201 family does not need any
protection diodes between the adjustment pin and the
output and from the output to the input to prevent die
overstress. Internal resistors are limiting the internal
current paths on the ADJ1pin. Therefore even with bypass
capacitors on the adjust pin no protection diode is
needed to ensure device safety under short-circuit
conditions. The Adjust pin can be driver on a transient
basis 7V with respect to the output without any device
degradation.00000000000000000000000000000000000
A protection diode between the Output pin and V_POWER
pin is not usually needed. Microsecond surge currents of
50A to 100A can be handled by the internal diode
between the Output pin and V_POWER pin of the device.0000
In normal operations it is difficult to get those values of
surge currents even with the use of large output
capacitances. Only with high value output capacitors,
such as 1000 F to 5000 F and the V_POWER pin is
instantaneously shorted to ground, damage can occour.
A diode from output to input is recommended (Figure 5).
VCONTROL
+
D1 D2
VPOWER
CONTROL
POWER OUTPUT
+
CS5201 ^SENSE
+
ADJ.
V_REF R1
VOUT
R2
Figure 5. Optional Clamp Diodes Protect Against Input
0000000Crowbar Circuits
If CS5201 is connected as a single supply device with the
control and power input pins shorted together the internal
diode between the output and the power input pin will
protect the control input pin.00000000000000000000000
Thermal Considerations
The CS5201 series have internal power and thermal
limiting circuitry designed to protect the device under
overload conditions. However maximum junction
temperature ratings should not be exceeded under
continuous normal load conditions. Careful consideration
must be given to all sources of thermal resistance from
junction to ambient, including junction-to-case, case-to-
heat sink interface and heat sink resistance itself.000000
Junction temperature of the Control section can run up to
125 . Junction temperature of the Power section can
run up to 150 .00000000000000000000000000000000
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