IC-MQF Datasheet, PDF (17/37 Pages) IC-Haus GmbH – PROGRAMMABLE 12-BIT Sin/Cos INTERPOLATION IC WITH RS422 DRIVER

iC-MQF PROGRAMMABLE 12-BIT ^preliminary
Sin/Cos INTERPOLATION IC WITH RS422 DRIVER
BIAS CURRENT SOURCE AND TEMPERATURE SENSOR CALIBRATION
Rev A1, Page 17/37
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). The IBN bias current
is measured by connecting pin VDDS and pin NB with
a 10 kΩ resistor. The setpoint is 200 µA which is equiv-
alent to a voltage drop of 2 V.
Notice: The measurement delivers a false reading
when outputs are tristate (due to a configuration er-
ror after cycling power, for instance).
CFGIBN
Code k
0x0
0x1
0x2
0x3
0x4
0x5
0x6
0x7
Adr 0x00, bit 3:0
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: Bias Current
Temperature Sensor
The temperature monitoring is calibrated in operating
mode Calibration 3.
The voltage VTs, at which the warning message is
generated, is determined first. A voltage ramp from
VDDS towards GNDS is applied to pin PA until pin ERR
displays the warning message. The following settings
are required for this measurement: EMASKA = 0x20,
EMTD = 0x00 and EPH = 0x00.
The signal at pin ERR switches from tristate to low (on
reaching the warning threshold VTs) and then from
low to tristate (on overshooting the threshold of the
overtemperature self protection which is not relevant
to calibration). To avoid confusion a clear change of
state (from low to high) should be generated with the
help of an external pull-up resistor at pin ERR.
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:
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 against VDDS) and must be set to the
calculated value by programming CFGTA(3:0).
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
0x10-0x1F
Notes
Adr 0x01, bit 4:0
VTth
∼
65+3k
65
100 %
Code k
0x8
VTth
∼
65+3k
65
137 %
105 %
0x9
142 %
109 %
0xA
146 %
114 %
0xB
151 %
118 %
0xC
155 %
123 %
0xD
160 %
128 %
0xE
165 %
132 %
0xF
169 %
reserved
With CFGTA = 0xF Toff is 80 °C typ.,
with CFGTA = 0x0 Toff is 155 °C typ.
Table 12: Temperature Monitoring