INA203A BURR-BROWN [Burr-Brown Corporation], INA203A Datasheet - Page 13

• Manufacturer Part Number: INA203A
• Description: Unidirectional Measurement Current-Shunt Monitor with Dual Comparators
• Manufacturer: BURR-BROWN [Burr-Brown Corporation]

TRANSIENT PROTECTION
The –16V to +80V common-mode range of the
INA203,
withstanding automotive fault conditions ranging from
12V battery reversal up to +80V transients, since no
additional protective components are needed up to
those levels. In the event that the INA203, INA204,
and INA205 are exposed to transients on the inputs
in excess of their ratings, then external transient
absorption with semiconductor transient absorbers
(zeners or Transzorbs) are necessary. Use of metal
oxide varistors (MOVs) or video disk recorders
(VDRs) is not recommended except when they are
used in addition to a semiconductor transient
absorber. Select the transient absorber such that it
will never allow the INA203, INA204, and INA205 to
be exposed to transients greater than +80V (that is,
allow for transient absorber tolerance, as well as
additional voltage because of transient absorber
dynamic impedance). Despite the use of internal
zener-type ESD protection, the INA203, INA204, and
INA205 do not lend themselves to using external
resistors in series with the inputs because the
internal gain resistors can vary up to 30% but are
closely matched. (If gain accuracy is not important,
then resistors can be added in series with the
INA203, INA204, and INA205 inputs with two equal
resistors on each input.)
OUTPUT VOLTAGE RANGE
The output of the INA203, INA204, and INA205 is
accurate within the output voltage swing range set by
the power-supply pin, V+. This performance is best
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INA204,
CMP1 IN /0.6V REF
CMP2 IN /0.6V REF
and
-
-
CMP1 IN+
CMP2 IN+
GND
OUT
INA205
V
Figure 33. Input Filter (Gain Error: 1.5% to –2.2%)
S
1
2
3
4
5
6
7
SO-14, TSSOP-14
is
INA203 INA205
1.2V REF
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ideal
-
V
SUPPLY
for
R
FILTER
14
13
12
11
10
9
8
< 100W
V
V
1.2V REF OUT
CMP1 OUT
CMP2 OUT
CMP2 DELAY
CMP1 RESET
illustrated when using the INA205 (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
An obvious and straightforward location for filtering is
at the output of the INA203, INA204, and INA205
series; however, this location negates the advantage
of the low output impedance of the internal buffer.
The only other option for filtering is at the input pins
of the INA203, INA204, and INA205, which is
complicated by the internal 5k
impedance;
Figure
minimizes both the initial shift in gain and effects of
tolerance. The effect on initial gain is given by
Equation
Total effect on gain error can be calculated by
replacing the 5k
or 5k
R
of 100
initial gain error will be 1.96%. Worst-case tolerance
conditions will always occur at the lower excursion of
the internal 5k
excursion of R
Gain Error % = 100 -
IN+
IN-
FILT
R
SHUNT
can also be inserted into the equation. If a pair
C
3mW
33. Using the lowest possible resistor values
FILTER
+ 30% (or 6.5k ). The tolerance extremes of
<< R
3:
1% resistors are used on the inputs, the
FILTER
R
this
FILTER
FILT
f
– 3% in this case.
<100W
-3dB
resistor (3.5k ), and the higher
term with 5k
configuration
=
100 ´
2 (2R
p
Load
FILTER
f
-3dB
5k + R
1
)C
W
FILTER
5kW
– 30%, (or 3.5k )
SBOS393 – MARCH 2007
is
FILT
+ 30% input
illustrated
INA203
INA204
INA205
(3)
13
in