1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

30

35

40

45

50

SUPPLY VOLTAGE (V)

-50

-25

0

25

50

75

100 125

90.0

92.5

95.0

97.5

100.0

102.5

105.0

TEMPERATURE (°C)

+IN_PGA=500mV

-50

-25

0

25

50

75

100

125

30

35

40

45

50

TEMPERATURE (°C)

13

LMP91200

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SNAS571E – JANUARY 2012 – REVISED FEBRUARY 2016

Product Folder Links: LMP91200

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Typical Characteristics (continued)

Unless otherwise specified, TA= 25°C, VS= (VDD – GND) = 3.3 V, VREF = 3.3 V.

Figure 31. PGA DC PSRR

vs Temperature

Figure 32. Supply Current

vs Temperature

Figure 33. Supply Current

vs Supply Voltage

7 Detailed Description

7.1 Overview

The LMP91200 is a sensor AFE for use in low-power, analytical-sensing applications. The LMP91200 is

designed for 2-electrode sensors. This device provides all of the functionality needed to detect changes based on

a delta voltage at the sensor. Optimized for low-power applications, the LMP91200 works over a voltage range of

1.8 V to 5.5 V. With its extremely low input bias current, it is optimized for use with pH sensors. Also, in the

absence of supply voltage, the very low input bias current reduces degradation of the pH probe when connected

to the LMP91200. Two guard pins provide support for high parasitic impedance wiring.