11

FN7490.1

March 9, 2006

Description of Operation and Applications

Information

Product Description

The EL8170 and EL8173 are micropower instrumentation

amplifiers (in-amps) which deliver rail-to-rail input

amplification and rail-to-rail output swing on a single 2.9V to

5V supply. The EL8170 and EL8173 also deliver excellent

DC and AC specifications while consuming only 60µA typical

supply current. Because the EL8170 and EL8173 provide an

independent pair of feedback terminals to set the gain and to

adjust output level, these in-amps achieve high common-

mode rejection ratio regardless of the tolerance of the gain

setting resistors. The EL8173 is internally compensated for a

minimum closed loop gain of 10 or greater, well suited for

moderate to high gains. For higher gains, the EL8170 is

internally compensated for a minimum gain of 100. An

ENABLE pin is used to reduce power consumption, typically

2.9µA, while the instrumentation amplifier is disabled.

Input Protection

All input and feedback terminals of the EL8170 and EL8173

have internal ESD protection diodes to both positive and

negative supply rails, limiting the input voltage to within one

diode drop beyond the supply rails. The EL8170 has

additional back-to-back diodes across the input terminals

and also across the feedback terminals. If overdriving the

inputs is necessary, the external input current must never

exceed 5mA. On the other hand, the EL8173 has no clamps

to limit the differential voltage on the input terminals allowing

FIGURE 38. EL8170 AND EL8173 SUPPLY CURRENT vs SUPPLY VOLTAGE

FIGURE 39. PACKAGE POWER DISSIPATION vs AMBIENT

TEMPERATURE

FIGURE 40. PACKAGE POWER DISSIPATION vs AMBIENT

TEMPERATURE

23.5

2.5

4.5

70

60

50

40

20

0

SUPPLY VOLTAGE (V)

5.5

30

10

4

35

909mW

θ

110

°C

/W

SO

8

1.4

1.2

1

0.8

0.6

0.2

0

JEDEC JESD51-7 HIGH EFFECTIVE THERMAL

CONDUCTIVITY TEST BOARD

0.4

0

25

50

75

100

150

AMBIENT TEMPERATURE (°C)

125

85

625mW

θ

60°

C/W

SO

8

1

0.9

0.8

0.6

0.4

0.1

0

0

25

50

75

100

150

AMBIENT TEMPERATURE (°C)

125

85

JEDEC JESD51-3 LOW EFFECTIVE THERMAL

CONDUCTIVITY TEST BOARD

0.2

0.7

0.3

0.5

EL8170, EL8173