高性能数字输出压力传感器4525DO系列

?PCB Mounted Digital Output Transducer

?Combination Temperature and Pressure

?I2C or SPI Protocol

?Differential, Gage, Absolute &

Compound

?Temperature Compensated

? 3.3 or 5.0 Vdc Supply Voltage

DESCRIPTION

The 4525DO is a small, ceramic based, PCB mounted pressure transducer from Measurement Specialties. The transducer is built using Measurement Specialties’ proprietary UltraStable? process and the

latest CMOS sensor conditioning circuitry to create a low cost, high performance Digital Output Pressure (14bit)

and Temperature (11bit) transducer designed to meet the strictest requirements from OEM customers.

The 4525DO is fully calibrated and temperature compensated with a total error band (TEB) of less than

1.0% over the compensated pressure range. The sensor operates from single supply of either 3.3 or 5.0Vdc.

The rugged ceramic transducer is available in side port, top port, and manifold mount and can measure absolute, gauge, differential or compound pressure from 1 to 150 psi. The 1/8” barbed pressure ports mate

securely with 3/32” ID tubing.

FEATURES APPLICATIONS

?PSI Pressure Ranges?Factory Automation

?PCB Mountable?Altitude and Airspeed Measurements

?Digital Output?Medical Instruments

?Barbed Pressure Ports ?Leak Detection

STANDARD RANGE (PSI)

Pressure Absolute Gauge Differential Compound

1 DS, SS, TP,MM DS, SS,TP,MM SS, TP

2 DS, SS, TP,MM DS, SS,TP,MM SS, TP

5 DS, SS, TP,MM DS, SS,TP,MM SS, TP

15 SS, TP DS, SS, TP,MM DS,MM SS, TP

30 SS, TP DS, SS, TP,MM DS,MM SS, TP

50 SS, TP DS, SS, TP,MM DS,MM SS, TP

100 SS, TP DS, SS, TP,MM DS,MM SS, TP

150 SS, TP DS, SS, TP,MM DS,MM SS, TP

BLOCK DIAGRAM

ABSOLUTE MAXIMUM RATINGS

Notes

Unit

Max

Parameter Conditions Min

Supply Voltage T A = 25 °C 2.7 5.7 V

Output Current T A = 25°C 3 mA

Voltage on any Pin T A = 25°C -0.3 Vsupply + 0.3 V

Storage Temperature -40 +125 °C

Humidity T A = 25°C 95 %RH Non Condensing Overpressure T A = 25 °C, both Ports 300 psi

Burst Pressure T A = 25 °C, Port 2 3X Range

kV

+4

ESD HBM -4

Solder Temperature 250°C, 5 sec max.

ENVIRONMENTAL SPECIFICATIONS

Parameter Conditions

Mechanical Vibration Mil Spec 202F, Method 213B, Condition C, 3 Drops

Mechanical Shock Mil Spec 202F, Method 214A, Condition 1E, 1Hr Each Axis

Thermal Shock 100 Cycles over Storage Temperature, 30 minute dwell

Life 1 Million FS Cycles

PERFORMANCE SPECIFICATIONS

Supply Voltage 1

: 5.0V or 3.3 Vdc

Reference Temperature: 25°C (unless otherwise specified)

PARAMETERS MIN

TYP

MAX

UNITS

NOTES Pressure Accuracy -0.25 0.25 %Span 2

Total Error Band (TEB) -1.0 1.0 %Span 3,6

Temperature Accuracy 1.5 oC 4

Supply

Current 3 mA 6 Compensated Temperature -10 85 oC 5

Operating Temperature -25 +105 oC

Output Pressure Resolution 12 ENOB

Output Temperature Resolution 7 ENOB

Response Time 1.5 mS 6

Start Time to Data Ready 4.3 mS

Weight 3 grams

Media Non-Corrosive Dry Gases Compatible with Silicon, Pyrex,

RTV, Gold, Ceramic, Nickel, and Aluminum

Notes

1. Output is not ratiometric to supply voltage.

2. The maximum deviation from a best fit straight line (BFSL) fitted to the output measured over the pressure range at 25C. Includes all

errors due to pressure non linearity, hysteresis, and non repeatability.

3. Total pressure error band includes all accuracy errors, thermal errors over the compensated temperature range and span and offset

calibration tolerances. For ideal sensor output with respect to input pressure and temperature, reference Transfer Function charts

below.

4. The maximum deviation from a best fit straight line (BFSL) fitted to the output measured over the compensated temperature range.

5. For errors beyond the compensated temperature range, see Temperature Error Multiplier chart below.

6. This product can be configured for custom OEM requirements, contact factory for lower power consumption or higher accuracy.

Prange is equal to the maximum full scale pressure specified in the ordering information.

I2C and SPI INTERFACE Specifications

1. I2C interface Specification

The serial interface of the 4515DO/4525DO series is optimized in terms of sensor readout and power consumption when the factory setting for I2C. For detailed specifications of the I2C protocol, see The I2C Bus Specification, Version 2.1, January 2000.

1.1 Interface connection-external

Bi-directional bus lines are implemented by the devices (master and slave) using open-drain output stages and a pull-up resistor connected to the positive supply voltage. The recommended pull-up resistor value depends on the system setup (capacitance of the circuit or cable and bus clock frequency). In most cases, 1 k?is a reasonable choice. The capacitive loads on SDA and SCL line have to be the same. It is important to avoid asymmetric capacitive loads.

1.2 I2C Address

The I2C address consists of a 7-digit binary value. The factory setting for I2C slave address is 0x28, 0x36 or 0x46 depending on the interface type selected from the ordering information. The address is always followed by a write bit (0) or read bit (1).The default hexadecimal I2C header for read access to the sensor is therefore 0x51, 0x6D, 0x8D respectively, based on the ordering information.

1.3 INT/SS pin

When programmed as an I2C device, the INT/SS pin operates as an interrupt. The INT/SS pin rises when new output data is ready and falls when the next I2C communication occurs. It is most useful if the part is configured in Sleep Mode to indicate to the system that a new conversion is ready.

1.4 Transfer sequences

Transmission START Condition (S):The START condition is a unique situation on the bus created by the master, indicating to the slaves the beginning of a transmission sequence (the bus is considered busy after a START).

Transmission STOP Condition (P):The STOP condition is a unique situation on the bus created by the master, indicating to the slaves the end of a transmission sequence (the bus is considered free after a STOP).

Acknowledge (ACK) / Not Acknowledge (NACK):Each byte (8 bits) transmitted over the I2C bus is followed by an acknowledge condition from the receiver. This means that after the master pulls SCL low to complete the transmission of the 8th bit, SDA will be pulled low by the receiver during the 9th bit time. If after transmission of the 8th bit the receiver does not pull the SDA line low, this is considered to be a NACK condition.

If an ACK is missing during a slave to master transmission, the slave aborts the transmission and goes into idle mode.

Handshake procedure (Hold Master):In a master-slave system, the master dictates when the slaves will receive or transmit data. However, in some situations a slave device may need time to store received data or prepare data to be transmitted. Therefore, a handshake procedure is required to allow the slave to indicate termination of internal processing

1.5 Data transfer format

Data is transferred in byte packets in the I2C protocol, which means in 8-bit frames. Each byte is followed by an acknowledge bit. Data is transferred with the most significant bit (MSB) first.

A data transfer sequence is initiated by the master generating the Start condition (S) and sending a header byte. The I2C header consists of the 7-bit I2C device address and the data direction bit (R/_W).

The value of the R/_W bit in the header determines the data direction for the rest of the data transfer sequence. If R/_W = 0 (WRITE) the direction remains master-to-slave, while if R/_W = 1 (READ) the direction changes to slave-to-master after the header byte.

1.6 Command Set and data Transfer Sequences

The I2C master command starts with the 7bit slave address with the 8th bit =1 (READ).The sensor as the slave sends an acknowledge (ACK) indicating success. The sensor has four I2C read commands: Read_MR, Read_DF2, Read_DF3, and Read_DF4.Figure 1.6 shows the structure of the measurement packet for three of

the four I2C read commands, which are explained in sections 1.6.1 and 1.6.2

Figure 1.6 – I2C Measurement Packet Reads

1.6.1 I2C Read_MR (Measurement Request)

The Read_MR (see example 1 in Figure 1.6) communication contains only the slave address and the READ bit(1) sent by the master. After the sensor responds with the slave ACK, the master must create a stop condition. This is only used in Sleep Mode (see section 3.1.2) to wake up the device and start a complete measurement cycle (including the special measurements) followed by the DSP calculations and writing the results to the digital output register.

Note: The I2C Read_MR function can also be accomplished using the I2C Read_DF2 or Read_DF3 command and ignoring the “stale” data that will be returned.

1.6.2 I2C Read_DF (Data Fetch)

For Data Fetch commands, the number of data bytes returned by the sensor is determined by when the master sends the NACK and stop condition. For the Read_DF3 data fetch command (Data Fetch 3 Bytes; see example 3 in Figure 1.6), the sensor returns three bytes in response to the master sending the slave address and the READ bit (1): two bytes of bridge data with the two status bits as the MSBs and then 1 byte of temperature data (8-bit accuracy). After receiving the required number of data bytes, the master sends the NACK and stop condition to terminate the read operation. For the Read_DF4 command, the master delays sending the NACK and continues reading an additional final byte to acquire the full corrected 11-bit temperature measurement. In this case, the last 5 bits of the final byte of the packet are undetermined and should be masked off in the application. The Read_DF2 command is used if corrected temperature is not required. The master terminates the READ operation after the two bytes of bridge data (see example 2 in Figure 1.6).

2.SPI interface Specification

The SPI interface of sensor must be programmed for falling-edge MISO change.

2.1 SPI Read_MR (Measurement Request)

A special SPI Read_MR command is used for waking up the part in Sleep Mode. It performs a measurement cycle including the special measurements and a correction calculation. The SPI Read_MR command only requires that the SS line be dropped low for a minimum of 8μs then raised high again. The riseof SS will trigger the part to power up and perform the measurements.

Figure 2.1– SPI Read_MR

Note: The SPI Read_MR function can also be accomplished using the SPI Read_DF command and ignoring the “stale” data that will be returned.

2.2 SPI Read_DF (Data Fetch)

For simplifying explanations and illustrations, only falling edge SPI polarity will be discussed in the following sections. The SPI interface will have data change after the falling edge of SCLK. The master should sample MISO on the rise of SCLK. The entire output packet is 4 bytes (32 bits). The high bridge data byte comes first, followed by the low bridge data byte. Then 11 bits of corrected temperature (T[10:0]) are sent: first the

T[10:3]byte and then the {T[2:0],xxxxx} byte. The last 5 bits of the final byte are undetermined and should be masked off in the application. If the user only requires the corrected bridge value, the read can be terminated after the 2nd byte. If the corrected temperature is also required but only at an 8-bit resolution, the read can be terminated after the 3rd byte is read.

Figure 2.2 – SPI Output Packet with Falling Edge SPI_Polarity

TIMING DIAGRAMS

I2C Timing Diagram

SPI Timing Diagram

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The information in this sheet has been carefully reviewed and is believed to be accurate; however, no responsibility is assumed for inaccuracies. Furthermore, this information does not convey to the purchaser of such devices any license under the patent rights to the

manufacturer. Measurement Specialties, Inc. reserves the right to make changes without further notice to any product herein. Measurement Specialties, Inc. makes no warranty, representation or guarantee regarding the suitability of its product for any particular purpose, nor does Measurement Specialties, Inc. assume any liability arising out of the application or use of any product or circuit and specifically disclaims any and all liability, including without limitation consequential or incidental damages. Typical parameters can and do vary in different applications. All operating parameters must be validated for each customer application by customer’s technical experts. Measurement Specialties, Inc. does not convey any license under its patent rights nor the rights of others.

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