MLX90609 Datasheet, PDF (12/22 Pages) List of Unclassifed Manufacturers – Angular Rate Sensor (Standard version)

MLX90609
Angular Rate Sensor (Standard version)
5.3 Usage of the ADC
The MLX90609 has the unique feature of simultaneously delivering an analog and a digital output
signal.
The MLX90609 includes an internal 11-bit successive-approximation-register ADC with a sample-
and-hold circuit and a programmable 2-channel analog multiplexer. The multiplexer connects the
OUTAR pin or the OUTTEMP pin to the sample-and-hold circuit.
After a power-up the ADC is in a sleep mode. Before usage of the sleeping ADC it's recommended
to use an initial dummy conversion. The result of this dummy conversion should be skipped but the
next conversions will be valid. After conversions the ADC can be put in the sleep mode again.
A conversion must be initiated by means of the SPI command ADCC. This command turns the
ADC on, sets a necessary channel and starts a conversion. To read a status of the conversion the
ADCR or STATR commands can be used. As soon as the conversion is completed, its result
should be read in the answer of the command ADCR (see tables 8, 9 and 10).
There are two conversion formulas below. The formulas reflect the typical ADC behavior and can
be used to evaluate the voltage on the OUTAR and OUTTEMP pins:
25
V_OUTAR (mV ) = ₁₂ ADCcode + 400
25
V_OUTTEMP (mV ) = ₁₆ ADCcode + 300
The ADCcode represents the 11-bit result of the conversion (see Table 10).
Table 6 gives a description of the bits that are mentioned in this section.
ADEN
BUSY
CHAN
EOC
OPC
X
The ADEN bit selects the power management mode of the ADC:
ADEN=0: ADC is switched to the sleep mode, no AD-conversion is allowed.
ADEN=1: AD-conversion is allowed.
This bit is set by the ADCC-command. After power-up bit ADEN is cleared.
This bit will be set after a reset and will be toggled to zero after all initialization procedures inside
the MLX90609. While BUSY=1, only refusal answers will be sent.
The CHAN bit is used to select the input source for the ADC.
CHAN=0: the angular rate channel.
CHAN=1: the temperature sensor channel.
This bit is set by the ADCC-command. After power-up bit CHAN is cleared.
End of AD-conversion bit. EOC bit indicates an ADC state.
EOC=0 : ADC in progress and can not be restarted.
EOC=1 : AD-conversion has been completed and can be restarted.
As a result, any attempt of the ADC starting will be rejected if EOC has a “0” state.
Unknown Operation Code. This bit is set when a received operation code was not recognized.
These bits are reserved or have an undefined state.
Table 6. SPI bits
390109060901
Rev 007
Page 12 of 22
Data Sheet
January/08