
ISL28006
22
FN6548.6
November 22, 2013
Overall Accuracy (VOA %)
VOA is defined as the total output accuracy Referred-to-Output
(RTO). The output accuracy contains all offset and gain errors, at
a single output voltage. Equation
4 is used to calculate the %
total output accuracy.
where
VOUT Actual = VSENSE x GAIN
Example: Gain = 100, For 100mV VSENSE input we measure
10.1V. The overall accuracy (VOA) is 1% as shown in Equation 5. Power Dissipation
It is possible to exceed the +150°C maximum junction
temperatures under certain load and power supply conditions. It
is therefore important to calculate the maximum junction
temperature (TJMAX) for all applications to determine if power
supply voltages, load conditions, or package type need to be
modified to remain in the safe operating area. These parameters
are related using Equation
6:
where:
PDMAXTOTAL is the sum of the maximum power dissipation of
each amplifier in the package (PDMAX)
PDMAX for each amplifier can be calculated using Equation 7: where:
TMAX = Maximum ambient temperature
θJA = Thermal resistance of the package
PDMAX = Maximum power dissipation of 1 amplifier
VCC = Total supply voltage
IqMAX = Maximum quiescent supply current of 1 amplifier
VOUTMAX = Maximum output voltage swing of the application
RL = Load resistance
FIGURE 80. TYPICAL APPLICATION CIRCUIT
gmHI
gmLO
1.35V
+
-
VCC
ADJ
OPTION
ONLY
I = 2.86A
GND
RS
RS-
RP
(1m
TO
0.1)
0.1VDC
TO
28VDC
+
-
CD
LOAD
CM
2.7VDC
TO
28VDC
RS+
FB
OUT
FIXED GAIN
OPTION
ONLY
VOA
100
VOUTactual VOUT
ected
exp
–
VOUT
ected
exp
------------------------------------------------------------------------------
×
=
(EQ. 4)
(EQ. 5)
VOA
100
10.1 10
–
10
-------------------------
×
1%
==
TJMAX
TMAX θJAxPDMAXTOTAL
+
=
(EQ. 6)
PDMAX
VS IqMAX VS
(
- VOUTMAX)
VOUTMAX
RL
------------------------
×
+
×
=
(EQ. 7)