ZHCSIP5 August 2018 PGA305
PRODUCTION DATA.
The PGA305 device can be used in a variety of applications. The most common ones are for pressure and temperature measurement. Depending on the application, the device itself can be configured in different modes. These sections give information regarding these configurations.
The PGA305 device is a high-accuracy, low-drift, low-noise, low-power, and easily programmable signal-conditioner device for resistive-bridge pressure and temperature-sensing applications. The PGA305 device implements a third-order temperature coefficient (TC) and nonlinearity (NL) algorithm to linearize the analog output. The PGA305 device accommodates various sensing element types, such as piezoresistive, ceramic film, and steel membrane. It supports the sensing element spans from 1 mV/V to 135 mV/V. The typical applications supported are pressure sensor transmitters, transducers, liquid-level meters, flow meters, strain gauges, weight scales, thermocouples, thermistors, two-wire resistance thermometers (RTD), and resistive field transmitters. The device can also be used in accelerometer and humidity sensor signal-conditioning applications.
The PGA305 device provides bridge excitation voltages of 2.5 V, 2 V, and 1.25 V, all ratiometric to the ADC reference level. The PGA305 device has the unique one-wire interface (OWI) that supports communication and configuration through the power-supply line during the calibration process. This feature minimizes the number of wires necessary for an application.
The PGA305 device contains two separated analog front-end (AFE) chains for resistive-bridge inputs and temperature-sensing inputs. Each AFE chain has its own gain amplifier and a 16-bit ADC at a 7.8-kHz output rate. The resistive-bridge input AFE chain consists of a programmable gain with 32 steps from 5 V/V to 400 V/V. For the temperature-sensing AFE input chain, the PGA305 device provides a current source that can supply up to 500 µA for optional external temperature sensing. This current source can also be used as constant-current bridge excitation. The programmable gain in the temperature-sensing chain has four steps from 1.33 V/V to 20 V/V. In addition, the PGA305 device integrates an internal temperature sensor that can be configured as the input of the temperature-sensing AFE chain.
A 128-byte EEPROM is integrated in the PGA305 device to store the calibration coefficients and the PGA305 configuration settings as needed. The PGA305 device has an integrated I2C interface used for data capture and also for device configuration. In addition, 14-bit DAC followed by a buffer gain stage of 2 V/V to 10 V/V. The device supports industrial-standard ratiometric-voltage output, absolute-voltage output, and 4-mA to 20-mA current loop.
The diagnostic function monitors the operating condition of the PGA305 device. The device can operate with a 3.3-V to 30-V power supply directly without using an external LDO. The PGA305 device has a wide ambient-temperature operating range from –40°C to 150°C. The package form is 6-mm × 6-mm, 36-pin VQFN. In this small package size, the PGA305 device has integrated all the functions necessary for resistive-bridge sensing applications to minimize the PCB area and simplify the overall application design.