MSK5950RH M. S Kennedy, MSK5950RH Datasheet - Page 5

• Manufacturer Part Number: MSK5950RH
• Description: Rad Hard Ultra Low Voltage Adjustable Positive Linear Regulator
• Manufacturer: M. S Kennedy

TYPICAL APPLICATIONS CIRCUIT
OUTPUT VOLTAGE SELECTION
The MSK 5950RH output voltage can be adjusted from 0 to 2V.
Three different resistor network schemes are used depending on
the required output voltage level.
For output voltages below the minimum feedback voltage toler-
ance of 1.225V, R3 as shown in Figure 1 can be omitted. Out-
put voltage can be calculated as follows:
Given:
V
V
V
For convenience Table 1 below provides standard 0.1% toler-
ance resistor values required to achieve several output voltages
based on nominal feedback voltage, R3 is ommitted.
For output voltages close to the feedback voltage tolerance of
1.225V-1.305V, a three resistor network may be used to im-
prove adjustment capabilities and trim out initial feedback volt-
age tolerances. Reference Figure 1.
VOUT= (R2R3V
REF
OUT
FB
APPLICATION NOTES CONT.
=1.265V
=2.5V
=V
FB
-((V
REF
FB
-V
+R1R3(V
FB
)/R2)R1
FIGURE 1
FB
-V
REF
)+R1R2V
FB)
/(R2R3)
5
For output voltages above the feedback voltage the unit should
be configured as shown in Figure 2.
As noted in the above typical applications circuit, the formula for
output voltage selection is:
V
A good starting point for this output voltage selection is set to
R2=1K. By rearranging the formula it is simple to calculate the
final R1 value.
R1=R2((V
Table 3 below lists some of the most probable resistor combina-
tions based on industry standard usage, R3 is ommitted.
V
loading and shunt current are carefully considered. If
used the pin should be pulled to ground.
OUT
REF
can be used as a precision 2.5V reference as long as circuit
=1.265(1+(R1/R2))
OUT
/1.265)-1)
V
OUT
=1.265(1+R1/R2)
FIGURE 2
PRELIMINARY
Rev. A 6/08
VREF
is not