Overview
The LMP91200MTX/NOPB, produced by Texas Instruments, is a configurable Analog Front-End (AFE) designed for low-power, analytical-sensing applications. This device is optimized for use with 2-electrode sensors, particularly pH sensors. It operates over a supply voltage range of 1.8 V to 5.5 V and is known for its extremely low input bias current, which minimizes errors in pH measurements. The LMP91200 is available in a 16-pin TSSOP package and operates within a temperature range of –40°C to 125°C. Its low power consumption and high accuracy make it suitable for various chemical sensing applications.
Key Specifications
| Parameter | Min | Typical | Max | Unit |
|---|---|---|---|---|
| Supply Voltage (VDD - GND) | 1.8 | - | 5.5 | V |
| Operating Temperature Range | -40 | - | 125 | °C |
| pH Buffer Input Bias Current (25°C) | -125 | - | 125 | fA |
| pH Buffer Input Offset Voltage | -200 | - | 200 | µV |
| Supply Current | - | 50 | - | µA |
| Package Type | - | - | - | 16-Pin TSSOP |
| Gain Bandwidth Product (pH Buffer) | - | 220 | - | KHz |
| DC Common-Mode Rejection Ratio (pH Buffer) | - | 80 | - | dB |
| DC Power Supply Rejection Ratio (pH Buffer) | - | 80 | - | dB |
Key Features
- Active Guarding: Two guard pins (GUARD1, GUARD2) to minimize input current leakage and support high parasitic impedance wiring.
- Low Input Bias Current: Extremely low input bias current in the range of tens of fA at room temperature, reducing errors in pH measurements.
- Low Power Consumption: Total current consumption of 50 µA while measuring pH.
- Wide Supply Voltage Range: Operates from 1.8 V to 5.5 V.
- High Accuracy: High DC common-mode rejection ratio (CMRR) and power supply rejection ratio (PSRR) of 80 dB.
- Temperature Stability: Operates over a temperature range of –40°C to 125°C.
Applications
- pH Sensor Platforms: Designed for use with 2-electrode pH sensors, ideal for chemical sensing applications.
- Analytical Sensing: Suitable for various analytical-sensing applications requiring high accuracy and low power consumption.
Q & A
- What is the primary application of the LMP91200?
The LMP91200 is primarily used in pH sensor platforms and other analytical-sensing applications.
- What is the supply voltage range of the LMP91200?
The LMP91200 operates over a supply voltage range of 1.8 V to 5.5 V.
- What is the input bias current of the pH buffer at room temperature?
The input bias current of the pH buffer is in the range of ±125 fA at room temperature.
- What is the typical supply current of the LMP91200?
The typical supply current of the LMP91200 is 50 µA.
- What is the operating temperature range of the LMP91200?
The LMP91200 operates over a temperature range of –40°C to 125°C.
- What package type is the LMP91200 available in?
The LMP91200 is available in a 16-pin TSSOP package.
- What is the gain bandwidth product of the pH buffer?
The gain bandwidth product of the pH buffer is 220 KHz.
- What are the DC common-mode rejection ratio and power supply rejection ratio of the pH buffer?
Both the DC common-mode rejection ratio and power supply rejection ratio of the pH buffer are 80 dB.
- How does the active guarding feature benefit the LMP91200?
The active guarding feature, provided by the GUARD1 and GUARD2 pins, minimizes input current leakage and supports high parasitic impedance wiring.
- What is the significance of low input bias current in pH measurements?
The low input bias current reduces the voltage error produced by the input bias current and electrode resistance, ensuring more accurate pH measurements.
