INA330
INA3
30
SBOS260 – NOVEMBER 2002
THERMISTOR SIGNAL AMPLIFIER
FOR TEMPERATURE CONTROL
FEATURES
DESCRIPTION
● OPTIMIZED FOR PRECISION 10kΩ
THERMISTOR APPLICATIONS
● LOW OFFSET OVER TEMPERATURE:
0.009°C Temperature Error, –40°C to +85°C
The INA330 is a precision amplifier designed for thermoelectric cooler (TEC) control in optical networking applications. It
is optimized for use in 10kΩ thermistor-based temperature
controllers. The INA330 provides thermistor excitation and
generates an output voltage proportional to the difference in
resistances applied to the inputs. It uses only one precision
resistor plus the thermistor, thus providing an alternative to
the traditional bridge circuit. This new topology eliminates the
need for two precision resistors while maintaining excellent
accuracy for temperature control applications.
●
EXCELLENT LONG-TERM STABILITY
●
VERY LOW 1/f NOISE: (0.01Hz to 10Hz)
(Peak-to-Peak Equivalent to 0.0001°C)
● WIDE OUTPUT SWING: Within 10mV of Rails
An excitation voltage is applied to the thermistor (RTHERM)
and precision resistor (RSET), creating currents I1 and I2. The
current conveyor circuit produces an output current, IO, equal
to I1 – I2, which flows through the external gain-setting
resistor. A buffered voltage output proportional to IO is also
provided.
● SUPPLY RANGE: Single +2.7V to +5.5V
● microPACKAGE: MSOP-10
● REQUIRES ONLY ONE PRECISION RESISTOR
APPLICATIONS
The INA330 offers excellent long-term stability, and very low
1/f noise throughout the life of the product. The low offset
results in a 0.009°C temperature error from –40°C to +85°C.
It comes in MSOP-10 packaging and operates with supply
voltages from +2.7V to +5.5V. It is specified over the industrial temperature range, –40°C to +85°C, with operation from
–40°C to +125°C.
● THERMISTOR-BASED TEMPERATURE
CONTROLLERS FOR OPTICAL NETWORKING
● HIGH ACCURACY FOR TEC APPLICATIONS
● LASER TEMPERATURE CONTROL
V+
Enable High = On
Low = Off
PID CONTROLLER
9
VEXCITE
1V
V2
2
V1
3
5
6
VO
8
VREF
2.5V
10
7
I O = I1 – I2
I1
1
4
I2
Thermistor
RTHERM = 10kΩ
RSET
10kΩ
CFILTER
500pF
RG
200kΩ
D/A
Converter
VADJUST = +2.5V
INA330 In A Temperature Control Loop
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.
Copyright © 2002, 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.
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ABSOLUTE MAXIMUM RATINGS(1)
ELECTROSTATIC
DISCHARGE SENSITIVITY
Supply Voltage .................................................................................. +5.5V
Signal Input Terminals:
(Pins 1, 2, 3, 6, and 10) Voltage(2) ......................... –0.5V to (V+) + 0.5V
Current(2) ............................................... ±10mA
Output Short-Circuit(3) .............................................................. Continuous
Operating Temperature Range ....................................... –40°C to +125°C
Storage Temperature Range .......................................... –65°C to +150°C
Junction Temperature .................................................................... +150°C
Lead Temperature (soldering, 10s) ............................................... +300°C
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.
NOTES: (1) Stresses above these ratings may cause permanent damage.
Exposure to absolute maximum conditions for extended periods may degrade
device reliability. These are stress ratings only, and functional operation of the
device at these or any other conditions beyond those specified is not implied.
(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.
PACKAGE/ORDERING INFORMATION
PRODUCT
INA330
PACKAGE-LEAD
PACKAGE
DESIGNATOR(1)
SPECIFIED
TEMPERATURE
RANGE
PACKAGE
MARKING
ORDERING
NUMBER
TRANSPORT
MEDIA, QUANTITY
MSOP-10
DGS
–40°C to +85°C
TLB
"
"
"
"
INA330AIDGST
INA330AIDGSR
Tape and Reel, 250
Tape and Reel, 2500
"
NOTE: (1) For the most current specifications and package information, refer to our web site at www.ti.com.
PIN CONFIGURATION
Top View
2
MSOP
I2 (RSET)
1
10 I1 (RTHERM)
V2
2
9
V+
V1
3
8
VO
GND
4
7
IO (RG)
(Connect to V+)
5
6
Enable
INA330
INA330
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SBOS260
ELECTRICAL CHARACTERISTICS: VS = +5V
BOLDFACE limits apply over the specified temperature range, TA = –40°C to +85°C
At TA = +25°C, V1 = V2 = +1V, VADJUST = +2.5V, RSET = 10kΩ, RTHERM = 10kΩ, RG = 200kΩ, CFILTER = 500pF, external 1kHz filtering, unless otherwise noted.
INA330
PARAMETER
VOLTAGE EXCITATION BUFFERS
Voltage Range
Offset Voltage
vs Temperature
vs Power Supply
Offset Voltage Match(1)
vs Temperature
Input Bias Current
Output Current
VOS
∆VOS
PSR
CONDITION
MIN
RSET = 10kΩ, RTHERM = 10kΩ
RSET = 100kΩ, RTHERM = 100kΩ
VS = +5V, V1 – V2 = 0
0.1
MAX
UNITS
1.25
V
V
µV
µV/°C
µV/V
µV
µV/°C
nA
µA
0.1 to 4.9
±60
±0.2
3
±30
0.2
±0.2
VS = +2.7V to +5.5V, V1 – V2 = 0
IB
+125
CURRENT CONVEYOR(2)
Gain Equation
Current Output Range
Voltage Compliance Range
Gain
Gain Error
Current Offset Error
Change Over Temperature
vs V1, V2
vs Power Supply
Noise Current
f = 0.01Hz to 10Hz
±12.5
0.075
IO = I1 – I2
4.925
1
±0.1
±100
VO = +0.075V to +4.925V
I1 = I2
+25°C to +85°C, or +25°C to –40°C
V1 = V2 = +0.1V to +1.25V
IERROR
OUTPUT BUFFER
Voltage Output Swing-to-Rail
Offset Voltage
vs Temperature
Input Bias Current
Short-Circuit Current
TYP
±0.2
±200
±40
±200
±100
25
12
500
RL = 100kΩ
RL = 10kΩ
75
dVOS /dT
ISC
5
10
30
0.1
Included in IERROR
±25
µA
V
A/A
%
nA
nA
nA/V
nA/V
pA/√Hz
pAp-p
mV
mV
µV
µV/°C
mA
NOTES: (1) Total errors in voltage seen between pin 1 and pin 10. (2) See Figure 2.
9
VEXCITE
1V
Enable High = On
Low = Off
V+
TEST CONFIGURATION
V2
2
V1
3
5
6
8
10
7
VO
IO = I1 – I2
I1
1
I2
4
Thermistor
RTHERM = 10kΩ
RSET
10kΩ
CFILTER
500pF
RG
200kΩ
VADJUST = +2.5V
INA330
SBOS260
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3
ELECTRICAL CHARACTERISTICS: VS = +5V (Cont.)
BOLDFACE limits apply over the specified temperature range, TA = –40°C to +85°C.
At TA = +25°C, V1 = V2 = +1V, VADJUST = +2.5V, RSET = 10kΩ, RTHERM = 10kΩ, RG = 200kΩ, CFILTER = 500pF, external 1kHz filtering, unless otherwise noted.
INA330
PARAMETER
FREQUENCY RESPONSE
Bandwidth, –3dB(3)
Slew Rate
POWER SUPPLY
Specified Voltage Range
Quiescent Current
Over Temperature
CONDITION
MIN
BW
SR
TYP
1
Not Slew Rate Limited
+2.7
IQ
MAX
IO = 0, V1 – V2 = 0V, VS = +5V
SHUTDOWN
Disable (Logic LOW Threshold)
Enable (Logic HIGH Threshold)
Enable Time
Disable Time
Shutdown Current and Enable Pin Current
TEMPERATURE RANGE
Specified Range
Operating Range
Storage Range
Thermal Resistance
2.6
kHz
+5.5
3.6
3.9
V
mA
mA
0.25
V
V
µs
µs
µA
1.6
75
100
2
VS = +5V, Disabled
–40
–40
–65
MSOP-10 Surface-Mount
5
+85
+125
+150
150
UNITS
°C
°C
°C
°C/W
NOTES: (3) Dynamic response is limited by filtering.
4
INA330
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SBOS260
TYPICAL CHARACTERISTICS
At TA = +25°C, V1 = V2 = +1V, VADJUST = +2.5V, RSET = 10kΩ, RTHERM = 10kΩ (5%), RG = 200kΩ, CFILTER = 500pF, and external 1kHz filtering, unless otherwise noted.
CURRENT CONVEYOR OFFSET ERROR
CHANGE OVER TEMPERATURE
PRODUCTION DISTRIBUTION
CURRENT CONVEYOR OFFSET ERROR
PRODUCTION DISTRIBUTION
Change in offset error from
+25°C to +85°C, or from
+25°C to –40°C.
–40
–36
–32
–28
–24
–20
–16
–12
–8
–4
0
4
8
12
16
20
24
28
32
36
40
A 40nA current offset error
variation with ambient
temperature results in a
0.009°C variation in setpoint temperature over
–40°C to +85°C ambient.
209
–190
–171
–152
–133
–114
–95
–76
–57
–38
–19
0
19
38
57
76
95
114
133
152
171
190
209
Population
Population
This error is generally
calibrated out.
Current Conveyor Offset Error (nA)
Current Conveyor Offset Error
Change Over Temperature (nA)
+5V
Test Configuration
for this page.
0.01Hz TO 10Hz VOLTAGE NOISE
VEXCITE
V2 2
1V
V1 3
0.001°C
200µV/div
0.0002°C/div
9
10
5
6
8
VO
INA330
7
I1
1
4
I2
5s/div
10kΩ
10kΩ
CFILTER
500pF
RG
200kΩ
2.5V
INA330
SBOS260
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5
APPLICATIONS INFORMATION
OVERVIEW
2
1V
8
3
Precision temperature controllers are generally adjusted to
their set-point temperature to achieve the desired system
performance and to compensate for tolerance of the thermistor and reference circuitry. After this adjustment, the
crucial issue is the stability of this set-point temperature.
When used in a temperature control loop (Figure 1), the
INA330 provides excellent control-point stability over time
and ambient temperature changes. Low 1/f noise assures
excellent short-term stability. Internal auto-zero circuitry assures excellent stability throughout product life.
Current Conveyor: measures
the current difference between
pins 10 and 1.
10
7
IO = I1 – I2 + IERROR + ∆IERROR /∆T
I1
I2
1
RTHERM
10kΩ at 25°C
9.55kΩ at 26°C
∆I = 4500nA
RSET
SOURCES OF ERRORS
The largest source of error in a control system will occur due
to RSET, see “Selecting Components” section.
FIGURE 2. Current Conveyor Portion of the INA330.
The INA330 errors are extremely low. The primary errors in
the INA330 occur in the current conveyer circuitry, as shown
in Figure 2. Equal currents in RSET and RTHERM produce a
small output current error of 200nA (maximum), and some
variation with temperature of 40nA (maximum). The offset is
calibrated out. Only the variation affects set-point stability.
ambient). This is the variation in set-point temperature due to
variation in ambient temperature of the INA330.
Insignificant Errors
Input offset voltage of the voltage excitation buffers are autozeroed to approximately 60µV and match to 30µV. Drift with
temperature is very low. They contribute negligible error.
The variation can be referred to the input as a set-point temp
variation: 10kΩ thermistor with a 4.5% temperature coefficient, (α = –0.045) changes resistance by 450Ω/°C. This
results in 4500nA change in I1 for a 1°C temperature change
at the thermistor. Therefore, the 40nA maximum current
offset error variation with ambient temperature results in a
0.009°C variation in set-point temperature over –40°C to
+85°C ambient (40nA/4500nA/°C = 0.009°C set-point/°C
Place 0.1µF capacitor close
to and across the power- 0.1µF
supply pins.
V+
V2
2
V1
3
Output buffer errors are auto-zeroed. When referred to the
input, their errors are negligible.
Gain error does not produce any significant temperature setpoint error when used in a temperature set-point control loop.
Enable High = On
Low = Off
PID CONTROLLER
9
VEXCITE
1V
Voltage excitation buffers have an input bias current of
0.2nA. With a source impedance of less than 10kΩ, errors
produced by the input bias current will be negligible.
5
6
VO
8
+0.9V/°C
for increasing
temperature.
Power
Amp
VREF
2.5V
TEC
10
7
IO = I 1 – I 2
I1
1
4
I2
Thermistor
RTHERM = 10kΩ
RSET
10kΩ
(Selection of RSET
significantly affects
control system—see
“Selecting Components”
section.)
CFILTER
500pF
RG
200kΩ
D/A
Converter
VADJUST = +2.5V
FIGURE 1. The INA330 In Simplified Temperature Control Loop.
6
INA330
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SBOS260
SELECTING COMPONENTS
RSET is the primary “reference” for the temperature control
loop. Its absolute resistance controls the set-point temperature. Again, its initial accuracy can be calibrated, but its
stability is crucial. Therefore, a high-quality, low-temperature
coefficient type must be used.
A 25ppm/°C precision resistor changes 0.15% from –40°C to
+85°C. This will produce a 0.03°C change in set-point temperature. This error is approximately three-times larger than
that produced by the INA330.
loop can be accomplished by simply reversing the connections to the TEC, or by creating the desired polarity in the
intervening control circuitry. If differing values of V1 and V2
are used, resistor values should be chosen to maintain
balanced currents, I1 and I2. Likewise, if a lower value of RSET
is used, the excitation voltage must be lowered to keep I1 and
I2 at or below 125µA.
CFILTER is calculated by:
CFILTER =
The transfer function for the configuration shown in Figure 3 is:
VO = VADJ + R G (I1 – I2 )
NOISE PERFORMANCE
or
Temperature control loops require low noise over a small
bandwidth, typically 10Hz, or less. The INA330’s internal
auto-correction circuitry eliminates virtually all 1/f noise (noise
that increases at low frequency). The peak-to-peak voltage
noise due to IERROR, RTHERM, RSET, and the buffers at 0.01Hz
to 10Hz results in a 0.0001°C contribution.
V1
V2
VO = VADJ + R G
–
R THERM R SET
With V1 = V2 = VEXCITE,
1
1
VO = VADJ + VEXCITE R G
–
R THERM R SET
V+
9
VEXCITE
1V
V2
2
V1
3
Enable
5
1
2πR G (1.6kHz)
OUTPUT
The INA330 output (pin 8) is capable of swinging to within
10mV of the power-supply rails. It is able to achieve rail-torail output performance while sinking or sourcing 12.5µA.
High = On
Low = Off
VADJUST can be used to create an offset voltage around which
the output can be centered.
6
8
VO
ENABLE FUNCTION
10
7
I O = I 1 – I2
I1
1
4
I2
Thermistor
RTHERM = 10kΩ
RSET
10kΩ
CFILTER
500pF
The INA330 is enabled by applying a logic HIGH voltage
level to the Enable pin. Conversely, a logic LOW voltage
level will disable the amplifier, reducing its supply current
from 2.6mA to typically 2µA. This pin should be connected to
a valid HIGH or LOW voltage or driven, not left open circuit.
Applications not requiring disable can connect pin 6 directly
to V+. The Enable pin can be modeled as a CMOS input
gate, as shown in Figure 4.
RG
200kΩ
VADJUST = +2.5V
V+
FIGURE 3. Basic Configuration for the INA330.
2µA
Nominal values should use RSET = RTHERM = 10kΩ at the
designed control temperature. Values less than 2kΩ can
cause the voltage excitation buffers to become unstable. The
buffer connected to pin 10 is characterized and tested to
supply the changing current in the thermistor. The thermistor
should not be connected to pin 1. An inversion of the control
Enable
6
FIGURE 4. Enable Pin Model.
INA330
SBOS260
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7
INSIDE THE INA330
The INA330 is designed and tested for amplifying 10kΩ
thermistor signals used in the control of thermoelectric
coolers for optical networking applications. The simplified
schematic in Figure 5 shows the basic function of the
INA330. An excitation voltage is applied as V1 and V2.
Typically, these voltages are equal. They generate currents I1 and I2 in the thermistor and RSET resistor.
Auto-corrected current mirror circuitry around A1 and A2
produce an output current, IO, equal to the difference
current I1 – I2. The gain is set by the value of RG. The
output voltage, VO, is the voltage resulting from IO flowing
through RG.
The INA330 uses internal charge pumps to create voltages beyond the power-supply rails. As a result, the
voltage on RG can actually swing 20mV below the negative power-supply rail, and 100mV beyond the positive
supply rail. An internal oscillator has a frequency of
90kHz and accuracy of ±20%.
V+
Enable
9
5
6
Current Mirror
INA330
I2
2
V2
I2
A1
1
Current Mirror
I2
Current Mirror
I2
10
I1
RSET
I1 – I2
IO = I1 – I2
RTHERM
3
A2
A3
IO
8
VO
IO
Current Mirror
V1
4
7
RG
CFILTER
VADJUST
FIGURE 5. INA330 Simplified Schematic.
INA330 PIN 5
Pin 5 of the INA330 should be connected to V+ to ensure
proper operation.
COMPLETE TEMPERATURE CONTROLLER
See Figure 6 for a complete temperature control loop with a
TEC (thermoelectric cooler) for cooling and heating. PID
(proportional, integral, differential) control circuitry is shown
for loop compensation and stability.
The loop controls temperature to an adjustable set-point of
22.5°C to 27.5°C. The nominal 10kΩ at 25°C thermistor
ranges from approximately 11.4kΩ to 8.7kΩ over this range.
A 1V excitation voltage is applied to V1 and V2, producing a
nominal 100µA current in the 10kΩ RSET resistor. The ther-
8
mistor current is approximately 100µA at 25°C, but will vary
above or below this value over the ±2.5°C set-point temperature range. The difference of these two currents flows in the
gain-set resistor, RG. This produces a voltage output of
approximately 0.9V/°C.
The set-point temperature is adjusted with VADJ. Thus, the
voltage at VO is the sum of (IO)(RG) + VADJ. VADJ can be
manually adjusted or set with a Digital-to-Analog (D/A) converter. Optionally, set-point temperature can be adjusted by
choosing a different fixed value resistor more closely approximating the value of RTHERM at the desired temperature.
The noninverting input of the integrator in the PID compensation is connected to VBIAS. Thus, the feedback loop will
drive the heating or cooling of the TEC to force VO to equal
VBIAS. VADJ = 2.5V will produce a set-point temperature of
INA330
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SBOS260
25°C. VADJ = 2.5V + 0.9V will change the set-point by 1°C.
A 0V to 5V D/A converter will provide approximately ±2.5°C
adjustment range. A 12-bit D/A converter will allow for
approximately 0.001°C resolution on the set-point temperature.
source for V1 and V2 should be derived from the same
reference.
The PID loop compensation can be optimized for loop
stability and best response to thermal transients by adjusting
C1, C2, C3, R2, R3, and R4. This is highly dependant on the
thermal characteristics of the temperature-controlled block
and thermistor/TEC mounting. Figure 7 shows a circuit that
can be used as an intermediate circuit to easily adjust
components and determine system requirements.
For best temperature stability, the set-point temperature
voltage should be derived ratiometrically from VBIAS. A D/A
converter used to derive the set-point voltage should share
the same reference voltage source as VBIAS. Likewise, the 1V
TEC DRIVER AMPLIFIER OPTIONS
Enable
+5V
+5V(2)
VREF(1)
+5V
PID
C1
9
5
OPA569
DRV591
DRV593
DRV594
R2
R4
C2
2
V1
3
R1
➜
V2
3.3V
3.3V
6
4kΩ
✻
VO
C3
R3
10kΩ
8
INA330
10
10kΩ
VREF(1)
+5V
IO = I1 – I2
10kΩ
+5V
7
I1
10kΩ
10kΩ
OPA348
VBIAS(1)
Thermistor
RSET = 10kΩ
RSET
10kΩ
–
✻
+
TEC
✻
OPA569
✻
2.5V
10kΩ
Cooling
4
I2
OPA569
➜
1
➜
1kΩ
➜
1V(1)
2A Linear Amplifier
3A PWM Power Driver
3A PWM Power Driver
3A PWM Power Driver
10kΩ
CFILTER
500pF
VREF(1) = +5V
RG
200kΩ
Temperature
Adjust
➜
➜
D/A
Converter
NOTES: (1) Ratiometrically derived voltages.
(2) The INA330 can also use a 3.3V, supply;
however, components must be chosen appropriate
to the smaller output voltage range.
✻
indicates direction of voltage change for
rising temperature at the thermistor.
VADJUST = 0V to 5V
= 2.5V at 25°C Set-Point
FIGURE 6. PID Temperature Control Loop.
This versatile PID compensation circuit allows
independent adjustment of the Proportional,
Integral, and Derivative control signals to
facilitate optimization of loop dynamics. The
results can then be duplicated using the circuit
shown in Figure 6.
R7
10MΩ
R6
5kΩ
1/4
OPA4340
Enable
+5V
R2
200Ω
+1V
V2
2
V1
3
5
R9
100kΩ
R1
2kΩ
6
R4
10kΩ
8
1/4
OPA4340
1/4
OPA340
10
R5
5kΩ
C3
1µF
R12
100kΩ
4
RSET
10kΩ
1/2
OPA2340
Power
Amplifier
OPA569
DRV591
DRV593
DRV594
To
TEC
VBIAS
R13
1MΩ
7
1
Thermistor
RTHERM = 10kΩ
R11
10kΩ
Proportional
I1
I2
R15
10kΩ
VBIAS
C1
22nF
INA330
C4
0.1µF
R10
100kΩ
R3
10kΩ
VBIAS
7
R8
10kΩ
Integrator
TC: 1s to 10s
VBIAS
+5V
C2
1µF
CFILTER
500pF
RG
200kΩ
VADJ
Ref
VBIAS
1/4
OPA4340
R14
10kΩ
Differentiator
TC: 100ms to 1s
D/A
Converter
FIGURE 7. Diagnostic and Optimization PID Temperature Control Loop.
INA330
SBOS260
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9
100pF(1)
+5V
10MΩ(1)
9
REF3012
VEXCITE
1.25V
5
2µF(1)
6
+5V
2
8
3
VO
10MΩ(1)
0.1µF
Output
to Power Amp
OPA340
VREF
2.5V
INA330
Proportional-Integrator
compensation is simpler to
adjust and often provides
adequate thermal transient
response.
10
NOTE: (1) Time constants
were selected for THORLABS
model TCLM9 Laser Diode
Mount.
7
1
4
RTHERM
10kΩ
RSET
10kΩ
RG
200kΩ
CFILTER
500pF
VADJ
FIGURE 8. Simple PI Temperature Control Amplifier.
FILTERING
Subsequent stages will frequently provide adequate filtering
for the INA330. However, filtering can be adjusted through
selection of RGCFILTER, and by adding a filter at VO for the
desired trade-off of noise and bandwidth. Adjustment of
these components will result in more or less ripple due to
auto-correction circuitry noise and will also affect broadband
noise.
2
It is generally desirable to keep any resistor added at VO (see
RO in Figure 9) relatively low to avoid DC gain error created
by the subsequent stage loading. This may result in relatively
high values for the filter capacitor at VO to produce the
desired filter response. The impedance of this filter can be
scaled higher to produce smaller capacitor values if the load
impedance is very high. Electrolytic capacitors are not recommended for the filters due to dielectric absorption effects.
10
8
3
RO
100Ω
CO
1µF
7
1
CFILTER
500pF
RG
200kΩ
VADJ
FIGURE 9. Required 1.6kHz (or lower) Filtering.
10
INA330
www.ti.com
SBOS260
DIGITALLY COMPENSATED LOOP
The PID compensation can be replaced with a microcontroller
or DSP, as shown in Figure 10. An Analog-to-Digital (A/D)
converter would be used to digitize the output of the INA330.
The analog PID provides sufficient filtering inherently, and,
therefore requires no additional filtering. The digital control
loop shown in Figure 10 does not provide this inherent
filtering, requiring additional output filtering (RO and CO) as
shown to avoid sampling the internal chopping noise of the
INA330 and the A/D converter input and affecting accuracy.
High-frequency noise is created by internal auto-correction
circuitry and is highly dependent on the filter characteristics
+1V
V1
2
V2
3
5
Loop Compensation
is performed in DSP.
8
RSET
10kΩ
The traditional bridge circuit (Figure 11) uses three matched
resistors and a thermistor to detect temperature changes.
The INA326 and INA327 instrumentation amplifiers are well
suited to a bridge implementation for thermistor measurement.
6
RO
100Ω
A/D
Converter
DSP
D/A
Converter
CO
1µF
INA330
RTHERM
TRADITIONAL BRIDGE CIRCUIT
Enable
+5V
+5V
9
chosen. “Spurs” occur at approximately 90kHz and its harmonics which is reduced by additional filtering at or below
1kHz. This may be the dominant source of noise visible when
viewing the output on an oscilloscope. Low cutoff frequency
filters will provide lowest noise.
TEC
7
CFILTER
500pF
RG
200kΩ
VADJ
0V to 5V
Ref
D/A
Converter
Temp
Adjust
FIGURE 10. Digitally Compensated Loop.
VEXCITE
10kΩ(1)
✻
PID CONTROLLER
10kΩ(1)
10kΩ(2) 5kΩ
+5V
INA326
VREF
2.5V
✻ 10kΩ at set-point
temperature.
1nF
100kΩ
VADJ
D/A
Converter
NOTES: (1) Requires ratio matching tracking.
(2) Requires absolute accuracy and stability.
FIGURE 11. Traditional Bridge Circuit.
INA330
SBOS260
www.ti.com
11
PACKAGE DRAWING
DGS (S-PDSO-G10)
PLASTIC SMALL-OUTLINE PACKAGE
0,27
0,17
0,50
10
0,08 M
6
0,15 NOM
3,05
2,95
4,98
4,78
Gage Plane
0,25
1
0°– 6°
5
3,05
2,95
0,69
0,41
Seating Plane
1,07 MAX
0,15
0,05
0,10
4073272/B 08/01
NOTES: A.
B.
C.
A.
12
All linear dimensions are in millimeters.
This drawing is subject to change without notice.
Body dimensions do not include mold flash or protrusion.
Falls within JEDEC MO-187
INA330
www.ti.com
SBOS260
PACKAGE OPTION ADDENDUM
www.ti.com
25-Apr-2022
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
INA330AIDGST
ACTIVE
VSSOP
DGS
10
250
RoHS & Green
Call TI | NIPDAUAG
Level-2-260C-1 YEAR
-40 to 85
TLB
(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)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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