Datasheet

2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
2
4 6 8
10 12 14 16 18 20 22
V (V)
OUT
V (mV)
SENSE
24
INA202V TestedLimit
OUT
(1)
V
CM2
V
CM1
V
CM3
V
CM4
V ,V ,andV
CM2 CM3 CM4
illustratethevariance
fromparttopartoftheV thatcancause
CM
maximumV withV <20mV.
OUT SENSE
V testedlimitat
OUT
V =0mV,0 V£ CM1
SENSE
V£ .
S
NOTE:(1)INA200V TestedLimit=0.4V.INA201V TestedLimit=1V.
OUT OUT
Ideal
GainError%=100 -
5kW
5k +RW
FILT
100 ´
INA200
INA201
INA202
SBOS374C –NOVEMBER 2006–REVISED OCTOBER 2010 www.ti.com
series with the inputs since the internal gain resistors
can vary up to ±30%. (If gain accuracy is not
important, then resistors can be added in series with
the INA200, INA201, and INA202 inputs with two
equal resistors on each input.)
OUTPUT VOLTAGE RANGE
The output of the INA200, INA201, and INA202 is
accurate within the output voltage swing range set by
the power supply pin, V+. This performance is best
illustrated when using the INA202 (a gain of 100
version), where a 100mV full-scale input from the
shunt resistor requires an output voltage swing of
+10V, and a power-supply voltage sufficient to
achieve +10V on the output.
INPUT FILTERING
Figure 28. Example for Low V
SENSE
Case 2
(INA202, Gain = 100)
An obvious and straightforward location for filtering is
at the output of the INA200, INA201, and INA202
series; however, this location negates the advantage
SELECTING R
S
of the low output impedance of the internal buffer.
The only other option for filtering is at the input pins
The value chosen for the shunt resistor, R
S
, depends
of the INA200, INA201, and INA202, which is
on the application and is a compromise between
complicated by the internal 5kΩ + 30% input
small-signal accuracy and maximum permissible
impedance; this is illustrated in Figure 29. Using the
voltage loss in the measurement line. High values of
lowest possible resistor values minimizes both the
R
S
provide better accuracy at lower currents by
initial shift in gain and effects of tolerance. The effect
minimizing the effects of offset, while low values of
on initial gain is given by Equation 3:
R
S
minimize voltage loss in the supply line. For most
applications, best performance is attained with an R
S
value that provides a full-scale shunt voltage range of
50mV to 100mV. Maximum input voltage for accurate
(3)
measurements is 500mV.
Total effect on gain error can be calculated by
replacing the 5kΩ term with 5kΩ – 30%, (or 3.5kΩ) or
TRANSIENT PROTECTION
5kΩ + 30% (or 6.5kΩ). The tolerance extremes of
The –16V to +80V common-mode range of the
R
FILT
can also be inserted into the equation. If a pair
INA200, INA201, and INA202 is ideal for withstanding
of 100Ω 1% resistors are used on the inputs, the
automotive fault conditions ranging from 12V battery
initial gain error will be 1.96%. Worst-case tolerance
reversal up to +80V transients, since no additional
conditions will always occur at the lower excursion of
protective components are needed up to those levels.
the internal 5kΩ resistor (3.5kΩ), and the higher
In the event that the INA200, INA201, and INA202
excursion of R
FILT
– 3% in this case.
are exposed to transients on the inputs in excess of
Note that the specified accuracy of the INA200,
their ratings, then external transient absorption with
INA201, and INA202 must then be combined in
semiconductor transient absorbers (such as zeners)
addition to these tolerances. While this discussion
will be necessary. Use of MOVs or VDRs is not
treated accuracy worst-case conditions by combining
recommended except when they are used in addition
the extremes of the resistor values, it is appropriate to
to a semiconductor transient absorber. Select the
use geometric mean or root sum square calculations
transient absorber such that it will never allow the
to total the effects of accuracy variations.
INA200, INA201, and INA202 to be exposed to
transients greater than +80V (that is, allow for
COMPARATOR
transient absorber tolerance, as well as additional
voltage due to transient absorber dynamic
The INA200, INA201, and INA202 devices
impedance). Despite the use of internal zener-type
incorporate an open-drain comparator. This
ESD protection, the INA200, INA201, and INA202 do
comparator typically has 2mV of offset and a 1.3ms
not lend themselves to using external resistors in
(typical) response time. The output of the comparator
latches and is reset through the RESET pin; see
Figure 30.
12 Submit Documentation Feedback Copyright © 2006–2010, Texas Instruments Incorporated
Product Folder Link(s): INA200 INA201 INA202