REF102

R

2

R

1

Pt100

Cu

Cu

V+

K

6

10.0V

4

2

INA129

V

O

Ref

R

R3

G

100Ω = Pt100 at 0°C

ISA

TYPE

MATERIAL

SEEBECK

COEFFICIENT

( V/°C)

m

R , R

1

2

E

J

K

T

+Chromel

-Constantan

+Iron

-Constantan

+Chromel

-Alumel

+Copper

-Constantan

58.5

50.2

39.4

38

66.5k

76.8k

97.6k

102k

W

W

W

W

INA129

R

G

I

B

R

V

1

IN

+

A

1

I

O

Load

Ref

I

O

V

IN

R

1

· G

A

I

1

OPA177

±1.5 nA

OPA131

±50 pA

OPA602

±1 pA

OPA128

±75 fA

-

=

INA129

R

G

V

O

OPA13 0

Ref

R

1

1MW

=

1

2pR C

1

1

= 1.59 Hz

V

IN

+

f-3dB

C1

0.1mF

-

300W

+5V

R

G

INA129

V

O

Ref

2.5V

∆V

2.5V + ∆V

-

INA129-EP

www.ti.com

SBOS508A – DECEMBER 2009 – REVISED DECEMBER 2015

9 Power Supply Recommendations

The minimum power supply voltage for INA129-EP is ±2.25 V and the maximum power supply voltage is ±18 V.

This minimum and maximum range covers a wide range of power supplies; but for optimum performance, ±15 V

is recommended. TI recommends adding a bypass capacitor at the input to compensate for the layout and power

supply source impedance.

9.1 Low Voltage Operation

The INA129-EP can be operated on power supplies as low as ±2.25 V. Performance remains excellent with

power supplies ranging from ±2.25 V to ±18 V. Most parameters vary only slightly throughout this supply voltage

range.

Operation at very low supply voltage requires careful attention to assure that the input voltages remain within

their linear range. Voltage swing requirements of internal nodes limit the input common-mode range with low

power supply voltage. Figure 5 and Figure 6 show the range of linear operation for ±15 V, ±5 V, and ±2.5 V

supplies.

Figure 23. Bridge Amplifier

Figure 24. AC-Coupled Instrumentation Amplifier

Figure 25. Thermocouple Amplifier With RTD Cold-

Figure 26. Differential Voltage to Current Converter

Junction Compensation

Copyright © 2009–2015, Texas Instruments Incorporated

Submit Documentation Feedback

17

Product Folder Links: INA129-EP