H1085U Datasheet, PDF (4/5 Pages) Hi-Sincerity Mocroelectronics – 3A LOW DROPOUT POSITIVE VOLTAGE REGULATOR

HI-SINCERITY
MICROELECTRONICS CORP.
Spec. No. : Preliminary Data
Issued Date : 1998.06.01
Revised Date : 1999.08.01
Page No. : 4/5
• Protection Diode
(The figure is shown as Regulator with Reverse Diode Protection in advanced applications)
In general operation, H1085U does not need any protection diodes. From the cross-section structure of
H1085U, 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 50A to 100A. 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 H1085U 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.
• Advanced Applications
Vin=7V
H 1085U
10uF 10uF
GND
1K
2K
GND
Vo=1.5~3.45
10uF
GND
Adjustable Output Voltage
H 1085U
Vin
*20m ohm
GND
10uF
GND
H 1085U
GND
*20m ohm
Vo
10uF
GND
Paralleling Regulators
*20m ohm is ballast resistance..
The inter - connection of #18 wire could act as ballast resistance.
H1085U
V in
VO
1K
10uF
10uF
Zener Diode
or Voltage Reference
GND
GND
*Vo = Vref ( 1+R2/R1 ) + Iadj x R2
**Optional for improved ripple rejection.
Regulator with Reference
10uF
GND
H 1085U
Vin
Vo
10uF
GND
GND
100uF
GND
*Please refer to "protection diode section" for detailed description.
Regulator with Reverse Diode Protection
HSMC Product Specification