AK8999AD Datasheet, PDF (34/68 Pages) Asahi Kasei Microsystems – Pressure Sensor Control IC

CONFIDENTIAL
[AK8999A/AW/AD]
1.10) Offset Temperature Drift Adjustment
The offset temperature drift for the pressure sensor is adjusted, including the AK8999A internal error,
by using the offset voltage temperature drift adjustment EEPROM (address: 03h, 04h, 05h, data:
EOTP/N[8], EOTP/N[7:0]).
■Offset Temperature Drift Adjustment Example (@VDD:5V)
Adjusting the low and high temperature coefficient is explained separately.
When this function is not used, set the same data as EOTP[8:0] and EOTN[8:0].
 Adjusting the high temperature coefficient
EOTP[8]: Offset voltage adjustment sign bit
If unadjusted output is greater than the output reference voltage at Ta = 105 ºC, set
EOTP[8] = 1h.
If unadjusted output is smaller than the output reference voltage at Ta = 105 ºC, set
EOTP[8] = 0h.
EOTP[7:0]: Offset voltage adjustment bit: Adjust in 0.144mV/ºC steps (@VDD: 5V).
If the offset voltage is +300mV (with respect to the output reference voltage e.g.100mV) at Ta =
105C, set EOTP[1] = 1h, EOTP[6:0] = 26dec.
(100[mV]+300[mV])-(105[C]-25[C])*(0.144[mV/C]*26[dec]) = 100.5[mV]
 Adjusting the low temperature coefficient
EOTN[8]: Offset voltage adjustment sign bit
If unadjusted output is greater than the output reference voltage at Ta = -40 ºC, set
EOTN[8] = 0h.
If unadjusted output is smaller than the output reference voltage at Ta = -40 ºC, set
EOTN[8] = 1h.
EOTN[7:0]: Offset voltage adjustment: Adjust in -0.144mV/ºC steps (@VDD: 5V).
If the offset voltage is +300mV (with respect to the output reference voltage e.g.100mV) at
Ta=-40C, set EOTN[7] = 0h, EOTN[6:0] = 32dec.
(100[mV]+300[mV])-(-40[C]-25[C])*(-0.144[mV/C]*32[dec]) = 100.5[mV]
MS1600-E-00
- 34 -
2014/05