IC-PI datasheet(38/49 Pages) ICHAUS

38 / 49 page

preliminary

iC-PI PROGRAMMABLE 12-BIT

Sin/Cos INTERPOLATION IC WITH RS422 DRIVER

Rev B1, Page 38/48

Output Driver Configuration

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

or highside drivers, or can be switched off (tristate); the

mode of operation is determined 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 specification is to be

adhered to. The tolerances in Electrical Characteristics,

numbers 505 and 506, 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-PI low.

TRIHL

Addr. 0x22, bit 1:0

Code

Function

Push-pull operation

Highside driver mode (P channel open drain)

Lowside driver mode (N channel open drain)

Tristate

Table 57: Output Drive Mode

SSR

Addr. 0x22, bit 3:2

Code

Function

Nominal value 12 ns

Nominal value 25 ns

Nominal value 80 ns

Nominal value 220 ns

Note

For tolerances see Elec. Char. Nos. 505 and 506.

Table 58: Output Slew Rate

SIK

Addr. 0x22, bit 5:4

Code

Function

typ. 2 mA, linking logic or driver ICs

typ. 8 mA

typ. 40 mA

typ. 100 mA, recommended for RS422

Note

For tolerances see Elec. Char. Nos. 503 and 504.

Table 59: Output Short-Circuit Current

Minimum Edge Distance

MTD

Addr. 0x1F, bit 7:4

Code

tMTD

during ABZ Mode, and

UVW Mode

tclk()lo

during 191/193 Mode

0x0

25 ns

not available

0x1

50 ns

25 ns

0x2

75 ns

25 ns

0x3

100 ns

50 ns

0x4

125 ns

50 ns

0x5

150 ns

75 ns

0x6

200 ns

100 ns

0x7

300 ns

150 ns

0x8

400 ns

200 ns

0x9

550 ns

275 ns

0xA

800 ns

400 ns

0xB

1.0 µs

500 ns

0xC

1.3 µs

650 ns

0xD

1.6 µs

800 ns

0xE

3.2 µs

1.6 µs

0xF

6.4 µs

3.2 µs

Note

All timing specifications are nominal values.

Table 60: Minimum Edge Distance

The minimum edge distance of the output signals can

be preset by MTD(3:0). This setting limits the maximum

possible output frequency to ensure a safe transmission

to counters, which permits only a low input frequency

and thus cannot resolve glitches. The configuration

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.

IC-PI Datasheet(PDF) 38 Page - IC-Haus GmbH

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