l4913adies STMicroelectronics, l4913adies Datasheet - Page 11

• Manufacturer Part Number: l4913adies
• Description: Rad-hard Positive Fixed Voltage Regulators
• Manufacturer: STMicroelectronics

7.3
parasitic voltage, resistor RW1can be introduced to provide the necessary compensating
voltage signal to the ADJUST pin.
FPGA power supply lines
Because these devices are very sensitive to V
supply voltage (usually 1.5 V), special attention must be given by supply lines designers to
mitigate possible heavy ion L4913 disturbances. The worst case heavy ion effect can be
summarized as: the L4913 internal control loop being cut (made open) or short-circuited for
a sub-microsecond duration. During such an event, the L4913 die power element can either
provide excessive current or current supply stoppage to the output (V
about one microsecond, after which time the L4913 smoothly recovers to nominal operation.
To mitigate these "transients", it is recommended to implement the L4913 PCB layout as
follows:
●
●
●
With this implementation, the ELDO simulated worst transient case shows no more than 90
mV deviation from the nominal line voltage value.
Minimizing series/parallel parasitic inductances of the PC path
Using a low ESR 47 µF Tantalum V
capacitor in parallel with the former (to reduce dynamic ESR)
Inserting a 100-200 nH ferrite core on the V
OUT
filtering capacitor with a 470 nF ceramic
DD
OUT
transients beyond a few % of their nominal
-to-tantalum capacitor wire
OUT
) for a duration of
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