Integrated Pressure Transducer

High Performance Sensing in a Small Package

Honeywell’s Integrated Pressure Transducer (IPT) is a small, low cost, high accuracy pressure transducer that integrates easily into a customer’s application, providing pressure data in an industry standard SPI digital format. The core of the IPT is a proven Honeywell silicon piezo-resistive pressure sensor with both pressure and temperature sensitive bridge elements. The IPT is both small and lightweight and can be easily applied to a wide variety of applications that require high performance in a small package.

Applying coefficients stored in the on-board EEPROM to normalized IPT pressure and temperature digital output yields accurate pressure readings over the -40 to 85°C temperature range.

The IPT piezo-resistive pressure-sensing die contains two bridge circuits, one for pressure and one for temperature. The IPT provides an Analog–to-Digital Converter (ADC) for each of these data channels, 24-bit for pressure and 16-bit for temperature.

IPT Pressure Configurations
The absolute IPT is a single port device available in 20 and 50 psia pressure ranges. Internally, one side of the silicon diaphragm sees a hermetically sealed vacuum reference. All absolute pressures are measured with respect to vacuum. For example, at sea level an absolute IPT will provide corrected pressure readings of approximately 14.7 psia. The absolute IPT has a maximum total error band of ±0.04% full-scale output over a temperature range of -40 to 85°C.

The gauge IPT is a two-port device available in 1, 2, 5, 10 and 20 psig ranges. Instead of supplying a vacuum reference to one side of the silicon diaphragm, it is plumbed to an external reference, typically ambient pressure. Movement of the PPT gauge diaphragm is only characterized in one direction. For a gauge IPT to operate properly, the pressure at port P1 must always be greater than the pressure at port P2. The gauge IPT has a maximum total error band of ±0.10% full-scale output over a temperature range of -40 to 85°C.

The differential PPT is also a two-port device available in 1, 2, 5, 10 and 20 psid ranges. Except for different electrical biasing of the sensor signal conditioning circuitry, it is identical to the gauge IPT. However, the movement of the differential diaphragm is characterized in both directions. Port P1 may be either positive or negative with respect to port P2. For example, a 5-psi differential IPT will provide readings from -5 to +5 psid. The differential IPT has a maximum total error band of ±0.10% full-scale output over a temperature range of -40 to 85°C.

Demonstration Kit
Honeywell offers a demonstration kit for evaluation of the integrated pressure transducer (IPT).

The Honeywell IPT Demo Board firmware implements a set of commands to send the pressure and temperature output from the IPT over an RS232 communication line. In addition, EEPROM read/write commands are supported to change select contents of the IPT EEPROM. SPI signals are brought to the edge of the demo board allowing the user to examine communication between the demo board microcontroller and the IPT.

The demonstration kit includes an evaluation board, RS-232 communication cable, AC Adapter, Microsoft Windows Software and User’s Manual.

Honeywell’s IPT is an excellent choice for applications in Aerospace, Meteorology and Instrumentation. The IPT is a size-sensitive high-accuracy solution for a wide variety of applications such as:

• Unmanned Air Vehicles (UAVs)
• UAV Navigation Systems
• Cabin Air Pressure Systems
• Meteorological Stations
• Data Buoys
• Medical Equipment
• Remote Calibrators
• Test Equipment