l4995r STMicroelectronics, l4995r Datasheet - Page 16

• Manufacturer Part Number: l4995r
• Description: 5v, 500ma Low Drop Voltage Regulator
• Manufacturer: STMicroelectronics

Application information
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Note:
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Application information
Figure 26. L4995 application schematic
The input capacitor Cs > 200nF is necessary for the smoothing of line disturbances. The
output capacitor C01 > 100nF is necessary for the stability of the regulation loop. In order to
dampen output voltage oscillations during high load current surges, it is recommended an
additional electrolytic capacitor C02 > 10µF to be placed at the output pin.
Voltage regulator
Voltage regulator uses a p-channel transistor as a regulating element. With this structure,
very low dropout voltage at current up to 500mA is obtained. The output voltage is regulated
up to transient input supply voltage of 40V. No functional interruption due to over-voltage
pulses is generated. A short circuit protection to GND is provided.
The voltage regulator is active when En is high.
Figure 27. Behavior of output current versus regulated voltage Vo
Vi
Vi
Ctw
Ctw
Ctr
Ctr
Vcr
Vcr
Wi
Wi
Vcw
Vcw
En
En
Vs
Vs
watchdog
watchdog
Reference
Reference
Start up
Start up
Vo_ref
Voltage
Voltage
Vo
100mV
100mV
Low Voltage
Low Voltage
Ishort Ilim
1.25V
1.25V
+ _
+ _
Reset
Reset
Iout
Vo
Vo
Vo
Vo
Res
Res
gnd
gnd
s
s
Co1
Co1
Co2
Co2
L4995