MLX75030 Datasheet, PDF (32/72 Pages) Melexis Microelectronic Systems – Universal ActiveLight Sensor Interface

MLX75030 Universal ActiveLight Sensor Interface
Datasheet
Measurement Type
Temperature measurement
Ambient light measurements on all channels C and D
Active light measurements on channels A & B, with 32 pulses, pulse frequency of 48.1kHz,
Tdem=6us, Tdc_pulse=400us
DC + Active light measurements on channels A & B, with 32 pulses, pulse frequency of
48.1kHz, Tdem=6us, Tdc_pulse=400us
Temperature measurement + Ambient light measurements on all channels C & D + DC +
Active light measurements on channels A & B, with 32 pulses, pulse frequency of 48.1kHz,
Tdem=6us, Tdc_pulse=400us
Min. t_dr
(µs)
269
388
1513
1811
2079
Table 14 : Example measurement execution times t_dr
Max. t_dr
(µs)
298
430
1673
2002
2299
Note that the DR pin can be used as an interrupt for the master device as it indicates when a read-out cycle can be
started.
Note that measurement execution of ActiveLight measurement only is not allowed. ActiveLight measurements must
always be done with Ambient Light measurements.
CS
SCLK
MOSI
MISO
DR
Internal State
Tri state
SM/SD Comma nd
tcs_d r
S tatus Flags / Ctrl 1
tdr
Tri state
Idle State
Measurement CycleSM/SD
Figure 11 : Timing Diagram of a Measurement Cycle
Idle State
The SM command contains 3 option bits R₂R₁R₀. These bits set the polarity of the anti-aliasing filters, the switched capacitors
low pass filters and the ADC input buffer in active light channels A & B:
• R2: this bit inverts the op-amp in the anti-aliasing filter. The output will change from (Signal + Offset_opamp_aa) to
(Signal - offset_opamp_aa). In this way, by processing 2 measurements with inverted R2 bits, the offset of the AA
filter can be cancelled.
• R1: Inversion of the offset of active light_sclp_filter. The output will change from (Signal + Offset_opamp_sclp) to
(Signal - offset_opamp_sclp). In this way, by processing 2 measurements with inverted R1 bits, the offset of the
SCLP filter can be cancelled.
• R0: Inversion of the offset of the ADC_buffer. The output will change from (Signal + Offset_opamp_buf) to (Signal -
offset_opamp_buf). In this way, by processing 2 measurements with inverted R0 bits, the offset of the SCLP filter
can be cancelled.
• T: this bit replaces the light pulses by internal current pulses during the active light measurements.
REVISION 005 – DECEMBER 2013
3901075030
PAGE 32 OF 72