IC-MQ Datasheet, PDF (16/39 Pages) IC-Haus GmbH – PROGRAMMABLE 9-BIT Sin/Cos INTERPOLATION IC WITH RS422 DRIVER

iC-MQ PROGRAMMABLE 9-BIT
Sin/Cos INTERPOLATION IC WITH RS422 DRIVER
BIAS CURRENT SOURCE AND TEMPERATURE SENSOR CALIBRATION
Rev D4, Page 16/39
Bias Current
The calibration of the bias current source in operation
mode Calibration 1 (see Table 13) is prerequisite for
adherence to the given electrical characteristics and
also instrumental in the determination of the chip tim-
ing (e.g. clock frequency at SCL). For setup purposes
the IBN bias current is measured using a 10 kΩ resis-
tor by pin VDDS connected to pin NC. The setpoint is
200 µA which is equivalent to a voltage drop of 2 V.
Example: VTs(T₁) is ca. 650 mV, measured from
VDDS versus PA, with T₁ = 25 °C;
The necessary reference voltage VTth(T₁) is then cal-
culated. The required warning temperature T₂, tem-
perature coefficients TCs and TCth (see Electrical
Characteristics, Section E) and measurement value
VTs(T₁) are entered into this calculation:
CFGIBN
Code k
0x0
0x1
0x2
0x3
0x4
0x5
0x6
0x7
Adr 0x01, bit 7:4
IBN
∼
31
39−k
79 %
81 %
84 %
86 %
88 %
91 %
94 %
97 %
Code k
0x8
0x9
0xA
0xB
0xC
0xD
0xE
0xF
IBN
∼
31
39−k
100 %
103 %
107 %
111 %
115 %
119 %
124 %
129 %
Table 11: Calibration of Bias Current
Temperature Sensor
The temperature monitoring is calibrated in operating
mode Calibration 3.
To set the required warning temperature T₂ the tem-
perature sensor voltage VTs at which the warning
message is generated is first determined. To this
end a voltage ramp from VDDS towards GNDS is ap-
plied to pin PA until pin ERR displays the warning
message. The following settings are required here:
EMASKA = 0x20, EMTD = 0x00 and EPH = 0x00.
The signal at ERR first switches from tristate to low
(on reaching the warning threshold VTs) and then from
low to tristate (on overshooting the internal hysteresis
which is not relevant to calibration). To avoid confusion
a clear change of state (from low to high) must be gen-
erated with the help of an external pull-up resistor at
pin ERR.
VTth(T₁)
=
VTs(T₁) + TCs · (T₂ − T₁)
1 + TCth · (T₂ − T₁)
Example: For T₂ = T₁ + 100 K VTth(T₁) must be pro-
grammed to 443 mV.
Reference voltage VTth(T₁) is provided for a high
impedance measurement (10 MΩ) at output pin NA
(measurement versus VDDS) and must be set by pro-
gramming CFGTA(3:0) to the calculated value.
Example: Altering VTth(T₁) from 310 mV (measured
with CFGTA(3:0)= 0x0) to 443 mV is equivalent to
143 %, the closest value for CFGTA is 0x9;
CFGTA
Code k
0x0
0x1
0x2
0x3
0x4
0x5
0x6
0x7
Notes
Adr 0x01, bit 3:0
VTth
∼
65+3k
65
100 %
Code k
0x8
VTth
∼
65+3k
65
140 %
105 %
0x9
145 %
110 %
0xA
150 %
115 %
0xB
155 %
120 %
0xC
160 %
125 %
0xD
165 %
130 %
0xE
170 %
135 %
0xF
175 %
With CFGTA = 0xF Toff is 80 °C typ.,
with CFGTA = 0x0 Toff is 155 °C typ.
Table 12: Calibration of Temperature Monitoring