OMR183- OMR186 Series

Stability

The OMR183-186 Series requires the use of

an output capacitor as part of the device

frequency compensation.

For all operating

conditions, the addition of 150µF aluminum

electrolytic or a 22µF solid tantalum on the

output

will

ensure

stability.

Normally,

capacitors much smaller than this can be used.

Many different types of capacitors with widely

varying characteristics are available.

These

capacitors

differ

in

capacitor

tolerance

(sometimes ranging up to ±100%), equivalent

series

resistance,

and

capacitance

temperature coefficient.

The 150µF or 22µF values given will ensure

stability.

When the adjustment terminal is bypassed to

improve the ripple rejection, the requirement

for an output capacitor increases. The values

of 22µF tantalum or 150µF aluminum cover all

cases of bypassing the adjustment terminal.

Without bypassing the adjustment terminal,

smaller capacitors can be used with equally

good results and the table below shows

approximately what size capacitors are needed

to ensure stability.

Recommended Capacitor Values

Normally, capacitor values on the order of

100µF are used in the output of many

regulators to ensure good transient response

with heavy load current changes.

Output

capacitance can be increased without limit and

larger values of output capacitor further

improve stability and transient response of the

OM183SC regulators.

Output Voltage — Adjustable Regulators

The OMR183-OM186 devices develop a

1.25V reference voltage between the output

and the adjust terminal (see below).

By

placing a resistor, R1, between these two

terminals, a constant current is caused to flow

through R1 and down through R2 to set the

overall output voltage. Normally this current is

the specified minimum load current of 10mA.

Because IADJ is very small and constant when

compared with the current through R1, it

represents a small error and can usually be

ignored.

Basic Adjustable Regulator

APPLICATION NOTES

Input

Output

Adjustment

10µF

10µF Tantalum, 50µF Aluminum

None

10µF

22µF Tantalum, 150µF Aluminum

20µF

RADIATION TEST PROGRAM

The following chart is a summary of the test data collected on Radiation Tolerant OMR183-186

series at various doses. The chart depicts the Total Radiation Dose that each device was

exposed to on a step stress irradiation basis prior to failure. Failure is defined as any electrical

test that does not meet the limits of the device per the published data sheet specifications after

radiation testing.

Omnirel P/N

5K

10K

20K 30K

50K

60K

70K

80K

100K

150K

200K RAD

OMR183

Test Points

XX

X

OMR184

Test Points

XX

X

OMR185

Test Points

XXX

X

X

X

X

OMR186

Test Points

XXX

X

X

X