AK8996 Datasheet, PDF (44/74 Pages) Asahi Kasei Microsystems – Pressure Sensor Interface IC

[AK8996/W]
5) Note on the Use of Output Reference Voltage Switching Circuit (Level Shift)
S/H1 & Level Shift circuit is configured as shown here:
ELVR[9:6]=0h , ELVF[5:0]=0 0h : SW O FF
ELV R[9 : 6]
Rough adj.
DAC
E LVF[ 5: 0 ]
Le vel Shift
Fine adj.
DAC
LP F
S/H 1
R =3 2kΩ
VO
S/H 2
From this diagram, the switching operation inside the S/H1 differs between the code setup for
ELVR[9:6]=0h, ELVF[5:0]=00h (register LVR, LVF Address 1Bh, 1Ch) and otherwise. If the data is set
up as shown, both switches are turned off, while in other situations they are turned on.
In some circumstances, an adjustment step for the fine adjustment DAC on the VO pin or VOUT pin
cannot maintain the monotonicity between the ELVF[5:0]=00h and the other codes. Use adequate
care, especially when the output reference voltage is set around 0.5VDD.
6) Data Reproducibility at Measuring the Temperature Drift
AK8996 temperature drift data reproducibility experiments have been conducted. The
experimental result shown here indicates that the AK8996 temperature drift data reproducibility
is within ±0.3 mV. Note that the experimental result shown here is for reference:
Experiment conditions
Supply voltage:
5V
Input voltage:
40 mV (=VP-VN)
Output reference voltage:
0.5*VDD
Gain:
25 times
VO pin external capacitance:
10nF
Environmental temperature sweep: 25°C → -40°C → 25°C → 125°C → 25°C
Measurement pin:
VO pin, VOUT pin
Experiment result: The graph shows that the resulting variations are within ±0.3mV.
VOUT pin
MS1055-E-02
VO pin
44
2011/12