REF01/REF02/REF03

Rev. K | Page 13 of 20

TERMINOLOGY

Dropout voltage, sometimes referred to as supply voltage

headroom or supply-output voltage differential, is defined as

the minimum voltage differential between the input and output

necessary for the device to operate.

()

constant

min

=

−

=

L

OUT

IN

DO

I

V

V

V

Since the dropout voltage depends upon the current passing

through the device, it is always specified for a given load

current.

The temperature coefficient relates the change in output voltage

to the change in ambient temperature of the device, as normal-

ized by the output voltage at 25°C. This parameter is expressed

in ppm/°C and can be determined by the following equation:

()

( )

ppm/

10

C

25

6

o

o

×

−

×

−

=

1

2

OUT

1

OUT

2

OUT

OUT

T

T

V

T

V

T

V

TCV

where:

Thermally induced output voltage hysteresis represents the

change in output voltage after the device is exposed to a

specified temperature cycle. This may be expressed as either a

shift in voltage or a difference in ppm from the nominal output.

()

[]

V

C

25

_

_

TC

OUT

OUT

HYS

OUT

V

V

V

−

=

o

()

()

[]

ppm

10

C

25

C

25

6

_

_

×

−

=

o

o

OUT

TC

OUT

OUT

HYS

OUT

V

V

V

V

where:

Thermal hysteresis occurs mainly as a result of forces exhibited

upon the internal die by its packaging. The effect is more

pronounced in parts with smaller packages.

Long-term stability refers to the shift in output voltage at 25°C

after 1000 hours of operation in a 25°C environment. This may

also be expressed as either a shift in voltage or a difference in

ppm from the nominal output.

()

V

0

_

t

V

t

V

ΔV

OUT

1

OUT

LTD

OUT

−

=

()

()

()

[]

ppm

t

V

t

V

t

V

ΔV

OUT

OUT

1

OUT

LTD

OUT

6

0

0

_

10

×

−

=

where:

Line Regulation

Line regulation refers to the change in output voltage in

response to a given change in input voltage. It is expressed in

either percent per volt, ppm per volt, or microvolt per volt

change in input voltage. This parameter accounts for the effects

of self-heating.

Load Regulation

Load regulation refers to the change in output voltage in

response to a given change in load current, and is expressed

in either microvolts per milliamp, ppm per milliamp, or ohms

of DC output resistance. This parameter accounts for the effects

of self-heating.