INA270_07 BURR-BROWN [Burr-Brown Corporation], INA270_07 Datasheet - Page 9

• Manufacturer Part Number: INA270_07
• Description: Voltage Output, Unidirectional Measurement Current-Shunt Monitor
• Manufacturer: BURR-BROWN [Burr-Brown Corporation]

TRANSIENT PROTECTION
The –16V to +80V common-mode range of the
INA270 and INA271 is ideal for 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 INA270 and INA271 are
exposed to transients on the inputs in excess of their
ratings,
semiconductor
Transzorbs) will be necessary.
Use of 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 INA270 and INA271
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).
Figure 16. The INA270–INA271 can be easily connected for first- or second-order filtering. Remember to
Supply
use the appropriate buffer gain (INA270 = 1.4, INA271 = 2) when designing Sallen-Key configurations.
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IN+
INA270
external
5kW
R
A2
A1
S
transient
IN-
5kW
a) Single-Pole Filter
transient
Single-Pole Filter
R
L
PRE OUT
absorbers
Capacitor
Load
absorption
96kW
BUF IN
GND
(zeners
+2.7V to +18V
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V+
with
or
Output
Supply
Despite
protection, the INA270 and INA271 are not suited to
using external resistors in series with the inputs since
the internal gain resistors can vary up to 30%, but
are tightly matched (if gain accuracy is not important,
then resistors can be added in series with the
INA270 and INA271 inputs with two equal resistors
on each input).
OUTPUT VOLTAGE RANGE
The output of the INA270 and INA271 is accurate
within the output voltage swing range set by the
power-supply pin, V+.
The INA270 and INA271 readily enable the inclusion
of filtering between the preamp output and buffer
input. Single-pole filtering can be accomplished with
a single capacitor because of the 96k
impedance at PRE OUT on pin 3, as shown in
Figure
The INA270 and INA271 readily lend themselves to
second-order Sallen-Key configurations, as shown in
Figure
consider that the PRE OUT 96k
exhibits an initial variation of 30% with the addition
of a –2200ppm/ C temperature coefficient.
IN+
INA270
5kW
16a.
16b. When designing these configurations
R
A2
A1
S
the
b) Second-Order, Sallen-Key Filter
IN-
SBOS381A – FEBRUARY 2007 – REVISED APRIL 2007
use
5kW
Load
R
L
PRE OUT
of
Second-Order, Sallen-Key Filter Connection
C
FILT
internal
96kW
R
BUF IN
S
GND
output impedance
+2.7V to +18V
zener-type
C
FILT
V+
INA270
INA271
output
Output
ESD
9