Datasheet

= V
ERROR
10
3
V
REF
x ppm
ERROR
T
D
=
V
REF
x 'T
x 10
6
ppm
(V
REF_MAX
- V
REF_MIN
)
Temperature Range
Voltage
Temperature
V
REF_MAX
Change in Output Voltage
V
REF_MIN
LM4030
www.ti.com SNVS552B –MARCH 2008–REVISED APRIL 2013
TEMPERATURE COEFFICIENT
Temperature drift is defined as the maximum deviation in output voltage over the temperature range. This
deviation over temperature may be illustrated as shown in Figure 25.
Figure 25. Illustrative V
REF
vs Temperature Profile
Temperature coefficient may be expressed analytically as the following:
where
• T
D
= Temperature drift
• V
REF
= Nominal preset output voltage
• V
REF_MIN
= Minimum output voltage over operating temperature range
• V
REF_MAX
= Maximum output voltage over operating temperature range
• ΔT = Operating temperature range (3)
The LM4030 features a low temperature drift of 10ppm (max) to 30ppm (max), depending on the grade.
DYNAMIC OFFSET CANCELLATION AND LONG TERM STABILITY
Aside from initial accuracy and drift performance, other specifications such as thermal hysteresis and long-term
stability can affect the accuracy of a voltage reference, especially over the lifetime of the application. The
reference voltage can also shift due to board stress once the part is mounted onto the PCB and during
subsequent thermal cycles. Generally, these shifts in VREF arise due to offsets between matched devices within
the regulation loop. Both passive and active devices naturally experience drift over time and stress and
temperature gradients across the silicon die also generate offset. The LM4030 incorporates a dynamic offset
cancellation scheme which compensates for offsets developing within the regulation loop. This gives the LM4030
excellent long-term stability (40 ppm typical) and thermal hysteresis performance (75ppm typical), as well as
substantial immunity to PCB stress effects, despite being packaged in a tiny SOT-23.
EXPRESSION OF ELECTRICAL CHARACTERISTICS
Electrical characteristics are typically expressed in mV, ppm, or a percentage of the nominal value. Depending
on the application, one expression may be more useful than the other. To convert one quantity to the other one
may apply the following:
ppm to mV error in output voltage:
where
• V
REF
is in volts (V) and V
ERROR
is in milli-volts (mV) (4)
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