ZMD31010
RBic
Lite
TM
Low-Cost Sensor Signal Conditioner
Datasheet
If the SOT applies to correcting 2
nd
Order behavior of Tcg then the formula for bridge correction is as follows:
BR
= Gain_B[1 +
ΔT(SOT*ΔT
+ Tcg)]*[BR_Raw + Offset_B
_
+
ΔT*Tco)]
The bandgap reference gives a very linear PTAT signal, so temperature correction can always simply be
accomplished with a linear gain and offset term.
Corrected Temp Reading:
T
Where
T_Raw
Offset_T
Gain_T
=
=
=
Raw Temp reading converted from PTAT signal
TempSensor offset coefficient
TempSensor gain coefficient
=
Gain_T*[T_Raw
+
Offset_T]
1.3.1 EEPROM
The EEPROM contains the calibration coefficients for gain and offset, etc., and the configuration bits, such as
output mode, update rate, etc. When programming the EEPROM, an internal charge pump voltage is used so
a high voltage supply is not needed.
The charge pump is internally regulated to 12.5 V voltage and the programming time amounts to 6ms.
1.3.2 One-Wire Interface - ZACwire
TM
The IC communicates via a one-wire serial interface. There are different commands available for the
following:
•
•
•
Reading the conversion result of the ADC (Get_BR_Raw, Get_T_Raw)
Calibration Commands
Entering various test modes
o
DAC test modes
o
Oscillator, 1V, and Pre-Amp
o
EEPROM test modes
o
Oscillator override & Scan test modes
Reading from the EEPROM (dump of entire contents)
Writing to the EEPROM (trim setting, configuration, and coefficients)
Output Stage
•
•
1.4
1.4.1 Digital to Analog Converter (Output DAC)
An 11-bit DAC based on sub-ranging resistor strings is used for the digital-to-analog output conversion in the
analog ratiometric and absolute analog voltage modes. Selection during calibration configures the system to
operate in either of these modes. The design allows for excellent testability as well as low power
consumption.
RBic
Lite
™ Datasheet, Rev. 1.2, February 28, 2006
Page 7 of 38
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD [ Zentrum Mikroelektronik Dresden AG ]
