Sensor Compensation Overview

Compensation requires an examination of the sensor per-

formance over the operating pressure and temperature

range. Use a minimum of two test pressures (e.g., zero

and full span) and two temperatures. More test pressures

and temperatures result in greater accuracy. A typical

compensation procedure can be summarized as follows:

Set Reference Temperature (e.g., 25°C):

• Initialize each transducer by loading its respective

register with default coefficients (e.g., based on mean

values of offset, FSO, and bridge resistance) to pre-

vent overload of the MAX1455.

• Set the initial bridge voltage (with the FSODAC) to

half of the supply voltage. Measure the bridge volt-

age using the BDR or OUT pins, or calculate based

on measurements.

• Calibrate the output offset and FSO of the transducer

using the ODAC and FSODAC, respectively.

• Store calibration data in the test computer or

MAX1455 EEPROM user memory.

Table 14. ATIM Definition

Table 15. IRCA Decode

ATIM[3:0]

DURATION OF ANALOG SIGNAL SPECIFIED IN BYTE TIMES (8-BIT TIME)

0000

0001

0010

0011

0100

0101

0110

0111

1000

1001

1010

1011

1100

1101

1110

1111

In this mode, OUT is continuous; however, DIO accepts commands after 32,769 byte times. Do not parallel

connect DIO to OUT.

ICRA[3:0]

NAME

DESCRIPTION

0000

CONFIG

Configuration register

0001

ODAC

Offset DAC register

0010

OTCDAC

Offset temperature coefficient DAC register

0011

FSODAC

Full-scale output DAC register

0100

FSOTCDAC Full-scale output temperature coefficient DAC register

0101

Reserved. Do not write to this location (EEPROM test).

0110 to

1111

Reserved. Do not write to this location.

MAX1455

Low-Cost Precision Sensor Signal Conditioner

www.maximintegrated.com

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