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INA3
32 INA2332
®
INA332
INA2332
SBOS216B – SEPTEMBER 2001 - REVISED OCTOBER 2006
Low-Power, Single-Supply, CMOS
INSTRUMENTATION AMPLIFIERS
FEATURES
●
DESIGNED FOR LOW COST
●
HIGH GAIN ACCURACY: G = 5, 0.07%, 2ppm/
°
C
●
GAIN SET WITH EXT. RESISTORS FOR > 5V/V
●
HIGH CMRR: 73dB DC, 50dB at 45kHz
●
LOW BIAS CURRENT: 0.5pA
●
BANDWIDTH, SLEW RATE: 2.0MHz, 5V/
µ
s
●
RAIL-TO-RAIL OUTPUT SWING: (V+) – 0.02V
●
WIDE TEMPERATURE RANGE: –55
°
C to +125
°
C
●
LOW QUIESCENT CURRENT: 490
µ
A max/chan
●
SHUTDOWN: 0.01
µ
A
●
MSOP-8 SINGLE AND TSSOP-14 DUAL PACKAGES
APPLICATIONS
●
INDUSTRIAL SENSOR AMPLIFIERS:
Bridge, RTD, Thermocouple, Position
●
PHYSIOLOGICAL AMPLIFIERS: ECG, EEG, EMG
●
A/D CONVERTER SIGNAL CONDITIONING
●
DIFFERENTIAL LINE RECEIVERS WITH GAIN
●
FIELD UTILITY METERS
●
PCMCIA CARDS
●
AUDIO AMPLIFIERS
●
COMMUNICATION SYSTEMS
●
TEST EQUIPMENT
●
AUTOMOTIVE INSTRUMENTATION
DESCRIPTION
The INA332 and INA2332 are rail-to-rail output, low-power
CMOS instrumentation amplifiers that offer wide range, singlesupply, and bipolar-supply operation. Using a special manufacturing flow, the INA332 family provides the lowest cost available, while still achieving low-noise amplification of differential signals with low quiescent current of 415
µ
A (dropping to 0.01
µ
A when shut down). Returning to normal operation within microseconds, this INA can be used for battery or multichannel applications.
Configured internally in a gain of 5V/V, the INA332 offers flexibility in higher gains by choosing external resistors.
R
1
40k
Ω
G = 5 + 5(R
2
/R
1
)
10k
Ω
V
REF
40k
Ω
10k
Ω
A1
A2
V
IN
–
V
IN
+
The INA332 rejects line noise and its harmonics because common-mode error remains low even at higher frequencies.
High bandwidth and slew rate make the INA332 ideal for directly driving sampling Analog-to-Digital (A/D) converters as well as general-purpose applications.
With high precision, low cost, and small packages, the
INA332 outperforms discrete designs.
Additionally, because they are specified for a wide temperature range of –55
°
C to +125
°
C, the INA332 family can be used in demanding environments.
R
2
R
G
INA332
A3
V
OUT
INA2332
Ch A
Ch B
V+ V– Shutdown
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
Copyright © 2001-2006, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters.
www.ti.com
2
ABSOLUTE MAXIMUM RATINGS
(1)
Supply Voltage, V+ to V– .................................................................... 7.5V
Signal Input Terminals, Voltage
(2)
..................... (V–) – 0.5V to (V+) + 0.5V
Current
(2)
..................................................... 10mA
Output Short-Circuit
(3)
.............................................................. Continuous
Operating Temperature .................................................. –55
°
C to +125
°
C
Storage Temperature ...................................................... –65
°
C to +150
°
C
Junction Temperature .................................................................... +150
°
C
NOTES: (1) Stresses above these ratings may cause permanent damage.
Exposure to absolute maximum conditions for extended periods may degrade device reliability. (2) Input terminals are diode-clamped to the power-supply rails.
Input signals that can swing more than 0.5V beyond the supply rails should be current limited to 10mA or less. (3) Short-circuit to ground, one amplifier per package.
ELECTROSTATIC
DISCHARGE SENSITIVITY
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
PACKAGE/ORDERING INFORMATION
(1)
PRODUCT
Single
INA332AIDGK
"
Dual
INA2332AIPW
"
PACKAGE-LEAD
MSOP-8
"
TSSOP-14
"
PACKAGE
DESIGNATOR
DGK
"
PW
"
TEMPERATURE
RANGE
–55
°
C to +125
°
C
"
–55
°
C to +125
°
C
"
SPECIFIED
PACKAGE
MARKING
B32
"
2332A
"
ORDERING
NUMBER
INA332AIDGKT
INA332AIDGKR
INA2332AIPWT
INA2332AIPWR
TRANSPORT
MEDIA, QUANTITY
Tape and Reel, 250
Tape and Reel, 2500
Tape and Reel, 250
Tape and Reel, 2500
NOTE: (1) For the most current package and ordering information, see the Package Option Addendum at the end of this data sheet, or see the TI web site at www.ti.com.
PIN CONFIGURATION
Top View
INA2332
RG 1
V
IN
–
V
IN
+
2
3
V– 4
INA332
MSOP-8 (DGK)
8 Shutdown
7 V+
6 V
OUT
5 REF
RGA
V
IN
–A
V
IN
+A
V–
V
IN
+B
V
IN
–B
RGB
5
6
7
3
4
1
2
14
13
12
11
Shutdown A
V
OUT
A
REFA
V+
REFB 10
9
8
V
OUT
B
Shutdown B
Dual, TSSOP-14 (PW) www.ti.com
INA332, INA2332
SBOS216B
ELECTRICAL CHARACTERISTICS: V
S
= +2.7V TO +5.5V
BOLDFACE limits apply over the specified temperature range, T
A
= –55
At T
A
= +25
°
C, R
L
= 10k
Ω
, G = 25, and V
CM
= V
S
/2, unless otherwise noted.
°
C TO +125
°
C
CONDITION MIN
INA332AIDGK
INA2332AIPW
TYP MAX PARAMETER
INPUT
Input Offset Voltage, RTI
Over Temperature
Temperature Coefficient
vs Power Supply
Over Temperature
Long-Term Stability
Input Impedance
Input Common-Mode Range
V
OS dV
OS
/dT
PSRR
V
S
= +5V
V
S
= +2.7V to +5.5V
±
2
±
5
±
50
±
0.4
10
13
|| 3
±
8
±
9
±
250
±
260
Common-Mode Rejection
Over Temperature
CMRR
V
S
= 2.7V
V
S
= 5V
V
S
= 5V, V
CM
= 0.55V to 3.8V
V
S
= 5V, V
CM
= 0.55V to 3.8V
V
S
= 2.7V, V
CM
= 0.35V to 1.5V
0.35
0.55
60
60
73
73
114
1.5
3.8
Crosstalk, Dual
INPUT BIAS CURRENT
Bias Current
Offset Current
I
B
I
OS
NOISE, RTI
Voltage Noise: f = 10Hz f = 100Hz f = 1kHz f = 0.1Hz to 10Hz
Current Noise: f = 1kHz
GAIN
(1)
Gain Equation, Externally Set
Range of Gain
Gain Error
vs Temperature
Nonlinearity
Over Temperature
OUTPUT
Output Voltage Swing from Rail
(2)
Over Temperature
Capacitance Load Drive
Short-Circuit Current e i
N
N
I
SC
FREQUENCY RESPONSE
Bandwidth, –3dB
Slew Rate
Settling Time, 0.1%
0.01%
Overload Recovery
BW
SR t
S
POWER SUPPLY
Specified Voltage Range
Operating Voltage Range
Quiescent Current per Channel I
Q
Over Temperature
Shutdown Quiescent Current/Chan I
SD
TEMPERATURE RANGE
Specified/Operating Range
Storage Range
Thermal Resistance
θ
JA
V
CM
= V
S
/2
R
S
= 0
Ω
G > 5
G = 5
G = 25, V
S
= 5V, V
O
= 0.05 to 4.95
G
≥
10
G = 25
V
S
= 5V, G = 25
G = 25, C
L
= 100pF, V
O
= 2V step
50% Input Overload G = 25
V
SD
> 2.5
(4)
V
SD
< 0.8
(4)
MSOP-8, TSSOP-14 Surface Mount
5
50
50
+2.7
–55
–65
±
0.5
±
0.5
2.0
5
1.7
2.5
2
280
96
46
7
0.5
G = 5 + 5(R
2
/R
1
)
±
0.07
±
2
±
0.001
±
0.002
25
See Typical Characteristics
(3)
+48/–32
+2.5 to +5.5
415
0.01
150
±
10
±
10
1000
±
0.4
±
10
±
0.010
±
0.015
+5.5
490
600
1
+125
+150
UNITS
pA pA nV/
√
Hz nV/
√
Hz nV/
√
Hz
µ
Vp-p fA/
√
Hz
V/V
%
ppm/
°
C
% of FS
% of FS
V
V
µ
A
µ
A
µ
A
MHz
V/
µ s
µ s
µ s
µ s
°
C
°
C
°
C/W
NOTES: (1) Does not include errors from external gain setting resistors.
(2) Output voltage swings are measured between the output and power-supply rails. Output swings to rail only if G
≥
10. Output does not swing to positive rail if gain is less than 10.
(3) See typical characteristic curve, Percent Overshoot vs Load Capacitance.
(4) See typical characteristic curve,
Shutdown Voltage vs Supply Voltage.
mV
mV
µ
V/
°
C
µ
V/V
µ
V/V
µ
V/month
Ω
|| pF
V
V dB
dB
dB dB mV
mV
pF mA
INA332, INA2332
SBOS216B
www.ti.com
3
4
TYPICAL CHARACTERISTICS
At T
A
= +25
°
C, V
S
= 5V, V
CM
= V
S
/2, R
L
= 10k
Ω
, and C
L
= 100pF, unless otherwise noted.
40
30
20
10
0
80
70
60
50
–10
–20
10
Gain = 500
Gain = 100
Gain = 25
Gain = 5
100
GAIN vs FREQUENCY
1k 10k
Frequency (Hz)
100k 1M 10M
120
100
80
60
40
20
0
10
COMMON-MODE REJECTION RATIO vs FREQUENCY
100 1k
Frequency (Hz)
10k 100k
POWER-SUPPLY REJECTION RATIO vs FREQUENCY
60
50
40
30
100
90
80
70
20
10
0
1 10 100 1k
Frequency (Hz)
10k 100k
6
5
4
V
V
MAXIMUM OUTPUT VOLTAGE vs FREQUENCY
S
S
= 5.5V
= 5.0V
3
2
1
0
100
V
S
= 2.7V
1k 10k 100k
Frequency (Hz)
1M 10M
0.1Hz TO 10Hz VOLTAGE NOISE
NOISE vs FREQUENCY
10k
1k
100 1
10
1 10 100 1k
Frequency (Hz)
10k 100k
0.1
100
10
1s/div
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INA332, INA2332
SBOS216B
TYPICAL CHARACTERISTICS
(Cont.)
At T
A
= +25
°
C, V
S
= 5V, V
CM
= V
S
/2, R
L
= 10k
Ω
, and C
L
= 100pF, unless otherwise noted.
OUTPUT SWING vs LOAD RESISTANCE
25
20
15
10
5
To Negative Rail
0
0 10k
To Positive Rail
20k
R
LOAD
(
Ω
)
30k 40k 50k
3
2
1
0
0
6
5
4
COMMON-MODE INPUT RANGE vs REFERENCE VOLTAGE
Outside of Normal Operation
REF
Increasing
1 2 3
Input Common-Mode Voltage (V)
4 5
500
450
400
350
300
250
200
150
100
50
0
2.5
QUIESCENT CURRENT AND SHUTDOWN CURRENT vs POWER SUPPLY
3
I
I
Q
SD
3.5
4 4.5
Supply Voltage (V)
5 5.5
QUIESCENT CURRENT AND SHUTDOWN CURRENT vs TEMPERATURE
350
300
250
200
150
100
50
0
600
550
500
450
400
–75 –50 –25 0
I
Q
25 50
Temperature (
°
C)
I
SD
75 100 125
150
60
50
40
30
20
10
0
2.5
SHORT-CIRCUIT CURRENT vs POWER SUPPLY
3 3.5
I
I
SC+
SC–
4 4.5
Supply Voltage (V)
5 5.5
SHORT-CIRCUIT CURRENT vs TEMPERATURE
60
50
40
I
SC+
I
SC–
30
20
10
0
–75 –50 –25 0 25 50
Temperature (
°
C)
75
100 125 150
INA332, INA2332
SBOS216B
www.ti.com
5
TYPICAL CHARACTERISTICS
(Cont.)
At T
A
= +25
°
C, V
S
= 5V, V
CM
= V
S
/2, R
L
= 10k
Ω
, and C
L
= 100pF, unless otherwise noted.
SMALL-SIGNAL STEP RESPONSE (G = 5) SMALL-SIGNAL STEP RESPONSE (G = 100)
4
µ s/div
SMALL-SIGNAL STEP RESPONSE
(G = 5, C
L
= 1000pF)
4
µ s/div
SMALL-SIGNAL STEP RESPONSE
(G = 100, C
L
= 1000pF)
4
µ s/div
SMALL-SIGNAL STEP RESPONSE
(G = 100, C
L
= 4700pF)
10
µ s/div
LARGE-SIGNAL STEP RESPONSE (G = 25)
6
10
µ s/div
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10
µ s/div
INA332, INA2332
SBOS216B
TYPICAL CHARACTERISTICS
(Cont.)
At T
A
= +25
°
C, V
S
= 5V, V
CM
= V
S
/2, R
L
= 10k
Ω
, and C
L
= 100pF, unless otherwise noted.
20
10
0
1
40
30
60
50
Output 2Vp-p
Differential
Input Drive
SETTLING TIME vs GAIN
0.01%
10
Gain (V/V)
100
0.1%
1k
PERCENT OVERSHOOT vs LOAD CAPACITANCE
60
50
40
30
100
90
80
70
20
10
0
10
Output 100mVp-p
Differential Drive
100 1k
Load Capacitance (pF)
G = 5
G = 25
10k
SHUTDOWN VOLTAGE vs SUPPLY VOLTAGE
3
2.5
2
Normal Operation Mode
1.5
1
Operation in this Region is not Recommended
0.5
0
2.5
3
Shutdown Mode
Part Draws Below 1
µ
A Quiescent Current
3.5
4 4.5
Supply Voltage (V)
5 5.5
5
0
15
10
25
20
OFFSET VOLTAGE PRODUCTION DISTRIBUTION
Offset Voltage (mV)
V
OUT
V
SD
SHUTDOWN TRANSIENT BEHAVIOR
50
µ s/div
14
12
10
8
20
18
16
2
0
6
4
OFFSET VOLTAGE DRIFT
PRODUCTION DISTRIBUTION
Offset Voltage (
µ
V/
°
C)
INA332, INA2332
SBOS216B
www.ti.com
7
TYPICAL CHARACTERISTICS
(Cont.)
At T
A
= +25
°
C, V
S
= 5V, V
CM
= V
S
/2, R
L
= 10k
Ω
, and C
L
= 100pF, unless otherwise noted.
SLEW RATE vs TEMPERATURE
4
3
2
8
7
6
5
1
0
–75 –50 –25 0 25 50
Temperature (
°
C)
75 100 125 150
INPUT BIAS CURRENT vs TEMPERATURE
10000
1000
100
10
1
0.1
–75 –50 –25 0 25 50
Temperature (
°
C)
75 100 125 150
CHANNEL SEPARATION vs FREQUENCY
120
100
80
60
40
20
0
1 10 100 1k 10k
Frequency (Hz)
100k 1M 10M
5
OUTPUT VOLTAGE SWING vs OUTPUT CURRENT
4
3
125
°
C 25
°
C –55
°
C
2
1
0
0 5 10 15 20 25 30 35 40
Output Current (mA)
45 50 55 60
8
www.ti.com
INA332, INA2332
SBOS216B
APPLICATIONS INFORMATION
The INA332 is a modified version of the classic two op amp instrumentation amplifier, with an additional gain amplifier.
Figure 1 shows the basic connections for the operation of the
INA332 and INA2332. The power supply should be capacitively decoupled with 0.1
µ
F capacitors as close to the INA332 as possible for noisy or high-impedance applications.
The output is referred to the reference terminal, which must be at least 1.2V below the positive supply rail.
OPERATING VOLTAGE
The INA332 family is fully specified over a supply range of
+2.7V to +5.5V, with key parameters tested over the temperature range of –55
°
C to +125
°
C. Parameters that vary significantly with operating conditions, such as load conditions or temperature, are shown in the Typical Characteristics.
The INA332 may be operated on a single supply. Figure 2 shows a bridge amplifier circuit operated from a single +5V supply. The bridge provides a small differential voltage riding on an input common-mode voltage.
2
V
IN
–
V
IN
+
3
R
1
Short V
OUT
to RG for G = 5
R
2
RG
1
G = 5 + 5 (R
2
/ R
1
)
DESIRED GAIN
(V/V)
5
10
50
100
R
1
R
2
OPEN
100k
Ω
10k
Ω
10k
Ω
SHORT
100k
Ω
90k
Ω
190k
Ω
REF
5
40k
Ω
10k
Ω
40k
Ω
A1
8
Shutdown
0.1
µ
F
V+
7
10k
Ω
A2
(For Single
Supply)
V–
4
A3
0.1
µ
F
6
V
O
= ((V
IN
+) – (V
IN
–)) • G
Also drawn in simplified form:
V
IN
+
REF
V
IN
–
3
5
2
V+
Shutdown
7
INA332
8
6
1
4
V– RG
V
OUT
FIGURE 1. Basic Connections.
Bridge
Sensor
+5V
V
IN
+
REF (1)
V
IN
–
3
5
2
V+
7
Shutdown
INA332
8
6
1
4
V–
RG
V
OUT
NOTE: (1) REF should be adjusted for the desired output level, keeping in mind that the value of REF affects the common-mode input range. See Typical Characteristics.
FIGURE 2. Single-Supply Bridge Amplifier.
INA332, INA2332
SBOS216B
www.ti.com
9
SETTING THE GAIN
The ratio of R
2
to R
1
, or the impedance between pins 1, 5, and 6, determines the gain of the INA332. With an internally set gain of 5, the INA332 can be programmed for gains greater than 5 according to the following equation:
G = 5 + 5 (R
2
/R
1
)
The INA332 is designed to provide accurate gain, with gain error less than 0.4%. Setting gain with matching TC resistors will minimize gain drift. Errors from external resistors will add directly to the error, and may become dominant error sources.
COMMON-MODE INPUT RANGE
The upper limit of the common-mode input range is set by the common-mode input range of the second amplifier, A2, to
1.2V below positive supply. Under most conditions, the amplifier operates beyond this point with reduced performance. The lower limit of the input range is bounded by the output swing of amplifier A1, and is a function of the reference voltage according to the following equation:
V
OA1
= 5/4 V
CM
– 1/4 V
REF
(See typical characteristic curve, Common-Mode Input Range vs Reference Voltage).
REFERENCE
The reference terminal defines the zero output voltage level.
In setting the reference voltage, the common-mode input of
A3 should be considered according to the following equation:
V
OA2
= V
REF
+ 5 (V
IN
+ – V
IN
–)
For ensured operation, V
OA2
should be less than V
DD
– 1.2V.
The reference pin requires a low-impedance connection. As little as 160
Ω
in series with the reference pin will degrade the
CMRR to 50dB. The reference pin may be used to compensate for the offset voltage (see the Offset Trimming section).
The reference voltage level also influences the commonmode input range (see the Common-Mode Input Range section).
INPUT BIAS CURRENT RETURN
With a high input impedance of 10
13
Ω
, the INA332 is ideal for use with high-impedance sources. The input bias current of less than 10pA makes the INA332 nearly independent of input impedance and ideal for low-power applications.
For proper operation, a path must be provided for input bias currents for both inputs. Without input bias current paths, the inputs will float to a potential that exceeds common-mode range and the input amplifier will saturate. Figure 3 shows how bias current path can be provided in the cases of microphone applications, thermistor applications, ground returns, and dc-coupled resistive bridge applications.
Microphone,
Hydrophone, etc.
V
IN
+
3
REF
V
IN
–
5
2
V+
Shutdown
7
INA332
8
6
1
4
47k
Ω
V– RG
V
B
(1)
V
OUT
Transformer
V
B
(1)
V
IN
+
3
REF
V
IN
–
5
2
V+
Shutdown
7
INA332
8
6
1
4
V–
V
OUT
RG
Center-tap provides bias current return
V
EX
Bridge
Amplifier
Bridge
Sensor
V
IN
+
3
REF
V
IN
–
5
2
V+
Shutdown
7
INA332
8
6
1
4
V–
V
OUT
RG
Bridge resistance provides bias current return
NOTE: (1) V
B
is bias voltage within common-mode range, dependent on REF.
FIGURE 3. Providing an Input Common-Mode Path.
When differential source impedance is low, the bias current return path can be connected to one input. With higher source impedance, two equal resistors will provide a balanced input. The advantages are lower input offset voltage due to bias current flowing through the source impedance and better high-frequency gain.
10
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INA332, INA2332
SBOS216B
SHUTDOWN MODE
The shutdown pin of the INA332 is nominally connected to V+.
When the pin is pulled below 0.8V on a 5V supply, the INA332 goes into sleep mode within nanoseconds. For actual shutdown threshold, see typical characteristic curve, Shutdown
Voltage vs Supply Voltage. Drawing less than 2
µ
A of current, and returning from sleep mode in microseconds, the shutdown feature is useful for portable applications. Once in sleep mode, the amplifier has high output impedance, making the INA332 suitable for multiplexing.
RAIL-TO-RAIL OUTPUT
A class AB output stage with common-source transistors is used to achieve rail-to-rail output for gains of 10 or greater.
For resistive loads greater than 10k
Ω
, the output voltage can swing to within 25mV of the supply rail while maintaining low gain error. For heavier loads and over temperature, see the typical characteristic curve, Output Voltage Swing vs Output
Current. The INA332’s low output impedance at high frequencies makes it suitable for directly driving Capacitive-Input
A/D converters, as shown in Figure 4.
+5V
V
IN
+
REF
V
IN
–
0.1
µ
F
3
5
2
V+
7
4
Shutdown
INA332
8
6
1
V
OUT
V– RG
OPA340
0.1
µ
F
V
OUT
FIGURE 5. Output Buffering Circuit. Able to drive loads as low as 600
Ω
.
V
IN
+
REF (1)
3
5
V
IN
–
2
V+
Shutdown
7
INA332
8
6
1
4
V–
RG
V
OUT
+5V
V
IN
+
REF
V
IN
–
3
5
2
V+
7
Shutdown
INA332
8
6
V
OUT
1
4
V–
RG
ADS7818
or
ADS7822
12-Bits f
S
< 100kHz
FIGURE 4. INA332 Directly Drives Capacitive-Input, High-
Speed A/D Converter.
OUTPUT BUFFERING
The INA332 is optimized for a load impedance of 10k
Ω
or greater. For higher output current the INA332 can be buffered using the OPA340, as shown in Figure 5. The OPA340 can swing within 50mV of the supply rail, driving a 600
Ω
load.
The OPA340 is available in the tiny MSOP-8 package.
OFFSET TRIMMING
The INA332 is laser trimmed for low offset voltage. In the event that external offset adjustment is required, the offset can be adjusted by applying a correction voltage to the reference terminal. Figure 6 shows an optional circuit for trimming offset voltage. The voltage applied to the REF terminal is added to the output signal. The gain from REF to
V
OUT
is +1. An op amp buffer is used to provide low impedance at the REF terminal to preserve good commonmode rejection.
OPA336
Adjustable
Voltage
NOTE: (1) REF should be adjusted for the desired output level.
The value of REF affects the common-mode input range.
FIGURE 6. Optional Offset Trimming Voltage.
INPUT PROTECTION
Device inputs are protected by ESD diodes that will conduct if the input voltages exceed the power supplies by more than
500mV. Momentary voltages greater than 500mV beyond the power supply can be tolerated if the current through the input pins is limited to 10mA. This is easily accomplished with input resistor R
LIM
, as shown in Figure 7. Many input signals are inherently current-limited to less than 10mA; therefore, a limiting resistor is not required.
V
IN
+
V
IN
–
R
I
OVERLOAD
10mA max
REF
R
LIM
LIM
3
5
2
V+
Shutdown
7
INA332
8
6
1
4
V– RG
V
OUT
FIGURE 7. Sample Output Buffering Circuit.
INA332, INA2332
SBOS216B
www.ti.com
11
OFFSET VOLTAGE ERROR CALCULATION
The offset voltage (V
OS
) of the INA332AIDGK is specified at a maximum of 500
µ
V with a +5V power supply and the common-mode voltage at V
S
/2. Additional specifications for power-supply rejection and common-mode rejection are provided to allow the user to easily calculate worst-case expected offset under the conditions of a given application.
Power-Supply Rejection Ratio (PSRR) is specified in
µ
V/V.
For the INA332, worst case PSRR is 200
µ
V/V, which means for each volt of change in power supply, the offset may shift up to 200
µ
V. Common-Mode Rejection Ratio (CMRR) is specified in dB, which can be converted to
µ
V/V using the following equation:
CMRR (in
µ
V/V) = 10
[(CMRR in dB)/–20]
• 10
6
For the INA332, the worst case CMRR over the specified common-mode range is 60dB (at G = 25) or about 30
µ
V/V
This means that for every volt of change in common-mode, the offset will shift less than 30
µ
V.
These numbers can be used to calculate excursions from the specified offset voltage under different application conditions. For example, an application might configure the amplifier with a 3.3V supply with 1V common-mode. This configuration varies from the specified configuration, representing a
1.7V variation in power supply (5V in the offset specification versus 3.3V in the application) and a 0.65V variation in common-mode voltage from the specified V
S
/2.
Calculation of the worst-case expected offset would be as follows:
Adjusted V
OS
= Maximum specified V
OS
+
(power-supply variation) • PSRR +
(common-mode variation) • CMRR
V
OS
= 0.5mV + (1.7V • 200
µ
V) + (0.65V • 30
µ
V)
=
±
0.860mV
However, the typical value will be smaller, as seen in the
Typical Characteristics.
FEEDBACK CAPACITOR IMPROVES RESPONSE
For optimum settling time and stability with high-impedance feedback networks, it may be necessary to add a feedback capacitor across the feedback resistor, R
F
, as shown in
Figure 8. This capacitor compensates for the zero created by the feedback network impedance and the INA332’s RG-pin input capacitance (and any parasitic layout capacitance).
The effect becomes more significant with higher impedance networks. Also, R
X
and C
L
can be added to reduce highfrequency noise.
V
IN
+
REF
V
IN
–
3
5
2
V+
INA332
7
Shutdown
8
6
C
IN
4
1
RG
R
IN
V–
R
F
C
F
R
X
C
L
V
OUT
R
IN
• C
IN
= R
F
• C
F
Where C
IN is equal to the INA332’s input capacitance
(approximately 3pF) plus any parastic layout capacitance.
FIGURE 8. Feedback Capacitor Improves Dynamic Performance.
It is suggested that a variable capacitor be used for the feedback capacitor since input capacitance may vary between instrumentation amplifiers, and layout capacitance is difficult to determine. For the circuit shown in Figure 8, the value of the variable feedback capacitor should be chosen by the following equation:
R
IN
• C
IN
= R
F
• C
F
Where C
IN
is equal to the INA332’s RG-pin input capacitance
(typically 3pF) plus the layout capacitance. The capacitor can be varied until optimum performance is obtained.
12
www.ti.com
INA332, INA2332
SBOS216B
APPLICATION CIRCUITS
MEDICAL ECG APPLICATIONS
Figure 9 shows the INA332 configured to serve as a low-cost
ECG amplifier, suitable for moderate accuracy heart-rate applications such as fitness equipment. The input signals are obtained from the left and right arms of the patient. The common-mode voltage is set by two 2M
Ω
resistors. This potential through a buffer provides optional right leg drive.
Filtering can be modified to suit application needs by changing the capacitor value of the output filter.
LOW-POWER, SINGLE-SUPPLY DATA
ACQUISITION SYSTEMS
Refer to Figure 4 to see the INA332 configured to drive an
ADS7818. Functioning at frequencies of up to 500kHz, the
INA332 is ideal for low-power data acquisition.
100k
Ω
Left Arm
Right Arm
+5V
100k
Ω
2k
Ω
V
R
= +2.5V
2k
Ω
2M
Ω
V
R
OPA336
0.1
µ
F
V
IN
+
3
REF
5
V
IN
–
2
V+
Shutdown
7
INA332
8
6
1
4
V–
2M
Ω
RG
V
R
1M
Ω
10k
Ω
10k
Ω
OPA336
Right
Leg
1.6nF
1M
Ω
1M
Ω
OPA336
V
OUT PUT
FIGURE 9. Simplified ECG Circuit for Medical Applications.
INA332, INA2332
SBOS216B
www.ti.com
13
www.ti.com
PACKAGE OPTION ADDENDUM
12-Sep-2006
PACKAGING INFORMATION
Orderable Device
INA2332AIPWR
INA2332AIPWRG4
INA2332AIPWT
INA2332AIPWTG4
INA332AIDGKR
INA332AIDGKRG4
INA332AIDGKT
INA332AIDGKTG4
Status
(1)
ACTIVE
ACTIVE
ACTIVE
ACTIVE
ACTIVE
ACTIVE
ACTIVE
ACTIVE
Package
Type
TSSOP
TSSOP
TSSOP
TSSOP
MSOP
MSOP
MSOP
MSOP
Package
Drawing
PW
PW
PW
PW
DGK
DGK
DGK
DGK
Eco Plan
(2)
Pins Package
Qty
14 2500 Green (RoHS & no Sb/Br)
Lead/Ball Finish MSL Peak Temp
(3)
CU NIPDAU Level-2-260C-1 YEAR
14 CU NIPDAU Level-2-260C-1 YEAR
14
2500 Green (RoHS & no Sb/Br)
250 Green (RoHS & no Sb/Br)
CU NIPDAU Level-2-260C-1 YEAR
14 CU NIPDAU Level-2-260C-1 YEAR
8
8
8
8
250 Green (RoHS & no Sb/Br)
2500 Green (RoHS & no Sb/Br)
2500 Green (RoHS & no Sb/Br)
250 Green (RoHS & no Sb/Br)
250 Green (RoHS & no Sb/Br)
CU NIPDAU
CU NIPDAU
CU NIPDAU
CU NIPDAU
Level-2-260C-1 YEAR
Level-2-260C-1 YEAR
Level-2-260C-1 YEAR
Level-2-260C-1 YEAR
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 1
www.ti.com
TAPE AND REEL INFORMATION
PACKAGE MATERIALS INFORMATION
30-Jan-2009
*All dimensions are nominal
Device
INA2332AIPWR
INA2332AIPWT
INA332AIDGKR
INA332AIDGKT
Package
Type
Package
Drawing
TSSOP
TSSOP
MSOP
MSOP
PW
PW
DGK
DGK
Pins
14
14
8
8
SPQ
2500
250
2500
250
Reel
Diameter
(mm)
Reel
Width
W1 (mm)
330.0
12.4
180.0
330.0
180.0
12.4
12.4
12.4
A0 (mm)
7.0
7.0
5.3
5.3
B0 (mm)
5.6
5.6
3.4
3.4
K0 (mm) P1
(mm)
W
(mm)
Pin1
Quadrant
1.6
1.6
1.4
1.4
8.0
8.0
8.0
8.0
12.0
12.0
12.0
12.0
Q1
Q1
Q1
Q1
Pack Materials-Page 1
www.ti.com
PACKAGE MATERIALS INFORMATION
30-Jan-2009
*All dimensions are nominal
Device
INA2332AIPWR
INA2332AIPWT
INA332AIDGKR
INA332AIDGKT
Package Type Package Drawing Pins
TSSOP
TSSOP
MSOP
MSOP
PW
PW
DGK
DGK
14
14
8
8
SPQ
2500
250
2500
250
Length (mm) Width (mm) Height (mm)
346.0
190.5
346.0
190.5
346.0
212.7
346.0
212.7
29.0
31.8
29.0
31.8
Pack Materials-Page 2
MECHANICAL DATA
MTSS001C – JANUARY 1995 – REVISED FEBRUARY 1999
PLASTIC SMALL-OUTLINE PACKAGE PW (R-PDSO-G**)
14 PINS SHOWN
0,65
14 8
0,30
0,19
0,10
M
1
A
7
4,50
4,30
6,60
6,20
0,15 NOM
Gage Plane
0
°
– 8
°
0,25
0,75
0,50
1,20 MAX
0,15
0,05
Seating Plane
0,10
DIM
PINS **
A MAX
8
3,10
A MIN 2,90
14
5,10
4,90
16
5,10
20
6,60
4,90 6,40
24
7,90
28
9,80
7,70 9,60
4040064/F 01/97
NOTES: A. All linear dimensions are in millimeters.
B. This drawing is subject to change without notice.
C. Body dimensions do not include mold flash or protrusion not to exceed 0,15.
D. Falls within JEDEC MO-153
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
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