AK8996 Datasheet, PDF (32/74 Pages) Asahi Kasei Microsystems – Pressure Sensor Interface IC

[AK8996/W]
■ Offset Voltage Adjustment Example
EOC[10]: Offset voltage rough adjustment sign bit
If unadjusted output is more than 0.5*VDD, set EOC[10]=0.
If unadjusted output is less than 0.5*VDD, set EOC[10]=1.
EOC[9:7]: Offset voltage rough adjustment: Adjust in 300mV steps (@VDD: 5V).
When EOC[10] = 0, adjust within -150 to +150mV (0.5*VDD reference).
When EOC[10] = 1, adjust within -150 to +150mV (0.5*VDD reference).
EOC[6]: Offset voltage fine adjustment sign bit
If unadjusted output is more than 0.5*VDD, set EOC[6]=0.
If unadjusted output is less than 0.5*VDD, set EOC[6]=1.
EOC[5:0]: Offset voltage fine adjustment: Adjust in 5mV steps (@VDD: 5V). For example,
When EOC[6] = 0 and the rough adjustment result is -150mV, set 30 dec = 1E hex.
When EOC[6] = 1 and the rough adjustment result is +150mV, set 30 dec = 1E hex.
Fine-tune the offset to within ±2.5mV (@VDD: 5V).
6. Output Span Voltage Adjustment
The output span voltage for the connected pressure sensor is adjusted, including the AK8996 inherent
error.
The output span voltage is adjusted using the output span voltage adjustment register (Address: 02h
data ESC[8], address: 03h data ESC[7:0]).
Since the sensitivity temperature drift is to be compensated for afterwards, the complete adjustment
cannot be performed. Final readjustment is required, including the level shift voltage error (See
Section 12).
■ Output Span Voltage Adjustment Example
When the output is 2400mV (@VDD: 5V), set ESC[8:0] = 160 dec.
2400 [mV]*100/60 = 4000 [mV]
When the output is 5600mV (@VDD: 5V), set ESC[8:0] = -160 dec.
5600 [mV]*100/140 = 4000 [mV]
Fine-tune the above output span voltage error so that it is within ±5mV (@VDD: 5V).
MS1055-E-02
32
2011/12