INA200A BURR-BROWN [Burr-Brown Corporation], INA200A Datasheet - Page 12

• Manufacturer Part Number: INA200A
• Description: High-Side Measurement Current-Shunt Monitor with Comparator and Reference
• Manufacturer: BURR-BROWN [Burr-Brown Corporation]

INA200
INA201
INA202
SBOS374 − NOVEMBER 2006
MOVs or 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 INA200, INA201, and INA202 to be exposed to
transients greater than +80V (that is, allow for transient
absorber tolerance, as well as additional voltage due to
transient absorber dynamic impedance). Despite the use
of internal zener-type ESD protection, the INA200,
INA201, and INA202 do not lend themselves to using
external resistors in 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
An obvious and straightforward location for filtering is at
the output of the INA200, INA201, and INA202 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 INA200,
12
CMP
GND
OUT
V+
IN
1
2
3
4
Figure 5. Input Filter (Gain Error — 1.5% to −2.2%)
Reference
SO−14, TSSOP−14
INA200− INA202
0.6V
Comparator
G
V
SUPPLY
R
FILTER
8
7
6
5
< 100Ω
V
V
CMP
RESET
IN+
IN−
R
INA201, and INA202, which is complicated by the internal
5kΩ + 30% input impedance; this is shown in Figure 5.
Using the lowest possible resistor values minimizes both
the initial shift in gain and effects of tolerance. The effect
on initial gain is given by Equation 3:
Total effect on gain error can be calculated by replacing the
5kΩ term with 5kΩ − 30%, (or 3.5kΩ) or 5kΩ + 30% (or
6.5kΩ). The tolerance extremes of R
inserted into the equation. If a pair of 100. 1% resistors are
used on the inputs, the initial gain error will be 1.96%.
Worst-case tolerance conditions will always occur at the
lower excursion of the internal 5kΩ resistor (3.5kΩ), and
the higher excursion of R
Note that the specified accuracy of the INA200, INA201,
and INA202 must then be combined in addition to these
tolerances. While this discussion treated accuracy
worst-case conditions by combining the extremes of the
resistor values, it is appropriate to use geometric mean or
root sum square calculations to total the effects of
accuracy variations.
COMPARATOR
The INA200, INA201, and INA202 devices incorporate an
open-drain comparator. This comparator typically has
2mV of offset and a 1.3µs (typical) response time. The
output of the comparator latches and is reset through the
RESET pin, see Figure 6.
SHUNT
OUT
Gain Error % + 100 * 100
C
3m Ω
FILTER
<< R
FILTER
R
FILTER
<100Ω
f
−3dB
=
2π(2R
Load
FILT
FILTER
f
−3dB
− 3% in this case.
1
)C
FILTER
5kW ) R
5kW
FILT
can also be
www.ti.com
FILT
(3)