AK8999A Datasheet, PDF (32/68 Pages) Asahi Kasei Microsystems – Pressure Sensor Control IC

CONFIDENTIAL
[AK8999A/AW/AD]
1.5) S/H Circuit Output Error Adjustment
The S/H circuit output voltage is adjusted to become 0.5*VDD at VOUT pin by using the Output
reference voltage adjustment EEPROM (address: 03h, 08h, data: ELV[8], ELV[7:0]).
Twr_REG CSCLK High Time
1
4
9
16
1
CSCLK
VOUT
Analog
Output
Hi-z
Level shift monitor
I2
1.6) Input gain (G1/G2) setup
Set up G1/G2 gain so that Gain Amp.1/2 output voltages become the ranges (In the case of
VDD = 5V, G1  1600mV, G2  1850mV). The voltage and temperature coefficient which are
used for calculation is as follows.
The offset voltage and the span voltage at 25C take the MAX values of the pressure sensor to be used.
And the offset voltage temperature drift coefficient and the sensitivity temperature drift coefficient take
the MIN values (minus polarity) of the pressure sensor to be used.
Voff25: Offset voltage of the pressure sensor@25C
Vsp25: Span voltage of the pressure sensor @25C
Ktoff: Offset voltage temperature drift coefficient of the pressure sensor (MIN value)
Ktsp: Sensitivity temperature drift coefficient of the pressure sensor (MIN value)
■ In the case of VDD = 5V and temperature = -40 to 105C
Gain Amp.1 output
= G1*(Voff25+Vsp25+ktoff*(-40[C]-25[C])+Vsp25*ktsp*(-40[C]-25[C]))  1600mV
Gain Amp.2 output
= G1*G2*(Vsp25+Vsp25*ktsp*(-40[C]-25[C]))  1850mV
■ In the case of VDD = 3.3V/3.0V and temperature = -40 to 105C
Gain Amp.1 output
= G1*(Voff25+Vsp25+ktoff*(-40[C]-25[C])+Vsp25*ktsp*(-40[C]-25[C]))  750mV/750mV
Gain Amp.2 output
= G1*G2*(Vsp25+Vsp25*ktsp*(-40[C]-25[C]))  990mV/850mV
MS1600-E-00
- 32 -
2014/05