IC-PI datasheet(27/49 Pages) ICHAUS

27 / 49 page

preliminary

iC-PI PROGRAMMABLE 12-BIT

Sin/Cos INTERPOLATION IC WITH RS422 DRIVER

Rev B1, Page 27/48

SIGNAL CONDITIONING CH1, CH2

It is recommended to use operating mode Test 5 for

the calibration of the sine signals. The sine signals are

also available in operating mode Calibration 2 for rea-

sons of compatibility with iC-MQ, but the amplitudes are

smaller (just 250 mVpeak instead of 1.5 Vpeak using

mode Test 5).

Alternatively, characteristic digital test signals are avail-

able for offset, amplitude and phase conditioning in

operating mode System Test.

Gain Settings

The gain is set in four steps:

1. The signal level control is to be shut down and the

constant current source for the ACO output is set to

a suitable output current (register ACOT = 0x2, ACOR

and ACOS values close to the later operating point).

2. The coarse gain factor GR12 is to be selected so

that differential signal amplitudes of approx. 6 Vpp are

to be produced in operating mode Test 5 (signal PSIN

versus NSIN and PCOS versus NCOS).

3. Using fine gain factor GF2, the cosine signal ampli-

tude is then to be adjusted to be exactly 6 Vpp.

4. The sine signal amplitude can then be adjusted to

the cosine signal amplitude via fine gain factor GF1.

This results in a total gain of GR12 x GFi for differential

input signals.

GND

Test 5

iC-PI

1.5 Vp

6 Vpp

1.5 Vp

pk(Nx)

pk(Px)

peak-to-peak

Figure 14: Definition of 6 Vpp differential test signal.

Termination R0 must be high-impedance

(resistive) during all Test and Calibration

modes.

GR12

Addr. 0x0a, bit 2:0

Code

Factor with input voltage

divider (R12 = 0x9)

Factor w/o input voltage

divider (R12 ̸= 0x9)

0x0

3.0

12.0

0x1

6.0

24.6

0x2

7.8

31.8

0x3

10.2

40.2

0x4

13.2

52.2

0x5

15.6

63.0

0x6

19.8

79.2

0x7

24.0

96.0

Notes

The values listed apply for all operating modes

except for Calibration 2 (reduces gain to 1/6).

The effective total gain is calculated using:

G12eff = GFx x GR12, or

G12eff = 1/4 x GFx x GR12

if using the input voltage divider (R12 = 0x9).

Table 24: Coarse Gain Factor CH1, CH2

GF2

Addr. 0x0c, bit 4:0

Code

Factor

0x00

1.00

0x01

1.06

...

6.25

GF2

0x1F

6.25

Table 25: Fine Gain Factor CH2

GF1

Addr. 0x0b, bit 6:0, Addr. 0x0a, bit 7:4

Code

Factor

0x000

1.0

0x001

1.0009

...

6.25

GF1

1984

0x7FF

6.6245

Table 26: Fine Gain Factor CH1

IC-PI Datasheet(PDF) 27 Page - IC-Haus GmbH

IC-PI Datasheet(HTML) 27 Page - IC-Haus GmbH

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

Datasheet Download

Link URL