IC-MQF Datasheet, PDF(29/37 Page) IC-Haus GmbH – PROGRAMMABLE 12-BIT Sin/Cos INTERPOLATION IC WITH RS422 DRIVER

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IC-MQF Datasheet, PDF (29/37 Pages) IC-Haus GmbH – PROGRAMMABLE 12-BIT Sin/Cos INTERPOLATION IC WITH RS422 DRIVER

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iC-MQF PROGRAMMABLE 12-BIT preliminary

Sin/Cos INTERPOLATION IC WITH RS422 DRIVER

Rev A1, Page 29/37

Output Driver Conï¬guration

The output drivers can be used as push-pull, lowside

or highside drivers; the mode of operation is deter-

mined by TRIHL(1:0).

The slew rate can be set using SSR to suit the length

of the cable. Lower slew rates are used to avoid steep

edges when transmitting via short wires, but can re-

sult in a limiting of the maximum permissible output

frequency. (For example, this frequency is 300 kHz at

a slew rate of 300 ns if the RS422 speciï¬cation is to be

adhered to. (the tolerances in Electrical Characteris-

tics, numbers 506/507, must be observed)).

The short-circuit current can be set by SIK and can be

minimized when connecting to on board logic or to an

external 24 V line driver. If the outputs are used as

RS422-compatible 5 V drivers, it is recommended that

SIK = 11 to keep the power dissipation of iC-MQF low.

TRIHL

Code

Addr 0x22, bit 1:0

Function

Push-pull operation

Highside driver mode (P channel open drain)

Lowside driver mode (N channel open drain)

Not permitted

Table 44: Output Drive Mode

SSR

Code

Note

Addr 0x22, bit 3:2

Function

Nominal value 12 ns

Nominal value 25 ns

Nominal value 80 ns

Nominal value 220 ns

See Elec. Char. 505/ 506

CFGOSZ

Code k

0x0

0x1

0x2

0x3

Addr 0x25, bit 2:0

140 %

130 %

120 %

110 %

Code k

0x4

0x5

0x6

0x7

105 %

100 %

92 %

n/a

Table 47: Calibration of MTD Oscillator

The calibration must be executed in Mode 191/193

with register MTD(3:0) = 0x0F. Apply a sine signal at

the inputs X3 to X6 and observe the length of the low

pulses at pin PB. The setting of CFGOSZ is correct if

the observed tclk()lo is close to the nominal value of

Elec. Char. no. 511.

MTD

Code

0x0

0x1

0x2

0x3

0x4

0x5

0x6

0x7

0x8

0x9

0xA

0xB

0xC

0xD

0xE

0xF

Note

Addr 0x1F, bit 7:4

Mode ABZ : tMTD

not available

Mode 191/193: tclk()lo

not available

50 ns

not available

75 ns

not available

100 ns

50 ns

125 ns

62.5 ns

150 ns

75 ns

175 ns

87.5 ns

200 ns

100 ns

300 ns

150 ns

400 ns

200 ns

600 ns

300 ns

800 ns

400 ns

1.0 Âµs

500 ns

1.2 Âµs

600 ns

1.4 Âµs

700 ns

1.6 Âµs

800 ns

All timing speciï¬cations are nominal values, see

Elec. Char. 514 for tolerances.

Table 48: Minimum Transition Distance

SIK

Code

Note

Table 45: Output Slew Rate

Addr 0x22, bit 5:4

Function

typ. 2 mA, linking logic or driver ICs

typ. 8 mA

typ. 40 mA

typ. 100 mA, recommended for RS422

See Elec. Char. 503/ 504

If CFGOSZ(2:0) is set correctly, the minimum tran-

sition distance of the output signals can be preset

by MTD(3:0). This setting limits the maximum possi-

ble output frequency to ensure a safe transmission to

counters, which permit only a low input frequency and

thus cannot debounce spikes. The conï¬guration of the

RS422 output drivers (with regard to the driver current

and slew rate) and the cable length must be taken into

account when choosing the minimum edge distance.

Table 46: Output Short-Circuit Current

Signal Filter

Minimum Transition Distance

ENF

the minimum transition distance in Mode ABZ, and 0

tclk()lo, the low pulse duration of the clock signals in 1

Mode 191/193 (see Elec.Char., no. 511 and no. 514).

Addr 0x03, bit 7

Function

Disabled

Noise limiting signal ï¬lter enabled (default)

Table 49: Noise Filter

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