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.

INA330

SBOS260 – NOVEMBER 2002

www.ti.com

DESCRIPTION

The INA330 is a precision amplifier designed for thermoelec-

tric cooler (TEC) control in optical networking applications. It

is optimized for use in 10k

Ω 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.

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.

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 indus-

trial temperature range, –40

°C to +85°C, with operation from

–40

°C to +125°C.

FEATURES

q OPTIMIZED FOR PRECISION 10k

Ω

THERMISTOR APPLICATIONS

q

LOW OFFSET OVER TEMPERATURE:

0.009

°C Temperature Error, –40°C to +85°C

q

EXCELLENT LONG-TERM STABILITY

q

VERY LOW 1/f NOISE: (0.01Hz to 10Hz)

(Peak-to-Peak Equivalent to 0.0001

°C)

q WIDE OUTPUT SWING: Within 10mV of Rails

q SUPPLY RANGE: Single +2.7V to +5.5V

q microPACKAGE: MSOP-10

q REQUIRES ONLY ONE PRECISION RESISTOR

Copyright © 2002, Texas Instruments Incorporated

THERMISTOR SIGNAL AMPLIFIER

FOR TEMPERATURE CONTROL

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.

APPLICATIONS

q THERMISTOR-BASED TEMPERATURE

CONTROLLERS FOR OPTICAL NETWORKING

q HIGH ACCURACY FOR TEC APPLICATIONS

q LASER TEMPERATURE CONTROL

D/A

Converter

2

3

10

1

95

4

V+

V

2

V

EXCITE

1V

V

1

6

Enable

High = On

Low = Off

8

7

I

1

I

2

R

SET

10k

Ω

R

G

200k

Ω

Thermistor

R

THERM = 10kΩ

C

FILTER

500pF

I

O = I1 – I2

V

O

V

REF

2.5V

PID CONTROLLER

INA330 In A Temperature Control Loop

V

ADJUST = +2.5V

INA33

0