HI-SINCERITY
MICROELECTRONICS CORP.
•
Protection Diode
Spec. No. : Preliminary Data
Issued Date : 1998.06.01
Revised Date : 2000.10.01
Page No. : 5/6
(The figure is shown as Regulator with Reverse Diode Protection in advanced applications)
In general operation, H1117J does not need any protection diodes. From the cross-section structure of H1117J,
the output pin is connected to P+ substrate, and the input pin is connected to N- well. There is a parasitic reverse
diode between them. It can handle microsecond surge currents of 5A to 10A. Even with large output capacitance,
it is very difficult to get those values of surge currents in normal operation. Only with high value output capacitors,
such as 1000uF. And with the input pin instantaneously shorted to ground. can damage occur. A crowbar circuit
at the input of the H1117J can generate those kinds of currents, and a diode from output to input is
recommended. Normal power supply cycling or even plugging and unplugging in the system will not generate
currents large enough to do any damage.
HSMC Product Specification
HSMC [ HI-SINCERITY MOCROELECTRONICS ]
