DLC 3V Digital I2C interface Compact High Resolution 16 bit Pressure Sensors Chip Series for Medical

DLC 3V Digital I2C interface Compact High Resolution 16 bit Pressure Sensors Chip Series for Medical Breathing Ventilators
DLC - Compact High Resolution Pressure Sensors Series
Introduction
The DLC Series Compact High Resolution Sensor is based on All Sensors’ CoBeam2 TM Technology. This reduces package stress susceptibility, resulting in improved overall long term stability. This technology breakthrough advances the state of the art for piezoresistive pressure sensors beyond what has been achieved for low pressure sensing using silicon based strain technology. Design engineers will find exceptional space savings with optimal performance for various compact applications.
The low supply voltage allows for integration of the sensors into a wide range of process control and measurement systems, as well as direct connection to I2C serial communications channels. The DLC series offers 16 bit digital resolution. The digital interface options ease integration of the sensors into a wide range of process control and measurement systems, allowing direct connection to serial communications channels. For battery-powered systems, the sensors can enter very low-power modes between readings to minimize load on the power supply.
These calibrated and compensated sensors provide accurate, stable output over a wide temperature range. This series is intended for use with non-corrosive, non-ionic working fluids such as air and dry gases.
Features
• Pressure Ranges from 1 inH2O to 150 psi
• High Resolution 16 bit Output
• Digital I2C Interface
• 1.8V to 3.6V Supply Voltage Range
• Compact Package Sizes As Small As 7mm x 7mm
Applications
• Medical Breathing
• Industrial Controls
• HVAC
• Environmental Controls
• Portable Equipment
I2C Interface
I2C Command Sequence
The part enters Idle state after power-up, and waits for a command from the bus master. Any of the five Measurement commands may be sent, as shown in Table 1. Following receipt of one of these commands, the EOC pin is set to Low level, and the sensor Busy bit is set in the Status Byte. After completion of measurement and calculation in the Active state, compensated data is written to the output registers, the EOC pin is set high, and the processing core goes back to Idle state. The host processor can then perform the Data Read operation, which for I2C is simply a 7-byte Device Read. If the EOC pin is not monitored, the host can poll the Status Byte by repeating the Status Read command, which for I2C is a one-byte Device Read. When the Busy bit in the Status byte is zero, this indicate that valid data is ready, and a full Data Read of all 7 bytes may be performed.
I2C Bus Communications Overview
The I2C interface uses a set of signal sequences for communication. The following is a description of the supported sequences and their associated mnemonics. Refer to Figure 3 for the associated usage of the following signal sequences.
Bus not Busy (I): During idle periods both data line (SDA) and clock line (SCL) remain HIGH.
START condition (ST): A HIGH to LOW transition of SDA line while the clock (SCL) is HIGH is interpreted as START condition. START conditions are always set by the master. Each initial request for a pressure value has to begin with a START condition.
Slave address (An): The I²C-bus requires a unique address for each device. The DLC sensor has a preconfigured slave address (see specification table on Page 3). After setting a START condition the master sends the address byte containing the 7 bit sensor address followed by a data direction bit (R/W). A “0” indicates a transmission from master to slave (WRITE), a “1” indicates a device-to master request (READ).
Acknowledge (A or N): Data is transferred in units of 8 bits (1 byte) at a time, MSB first. Each data-receiving device, whether master or slave, is required to pull the data line LOW to acknowledge receipt of the data. The Master must generate an extra clock pulse for this purpose. If the receiver does not pull the data line down, a NACK condition exists, and the slave transmitter becomes inactive. The master determines whether to send the last command again or to set the STOP condition, ending the transfer.
DATA valid (Dn): State of data line represents valid data when, after a START condition, data line is stable for duration of HIGH period of clock signal. Data on line must be changed during LOW period of clock signal. There is one clock pulse per data bit. STOP condition (P): LOW to HIGH transition of the SDA line while clock (SCL) is HIGH indicates a STOP condition. STOP conditions are always generated by the master.