Motorola MVME2600 manual Interface Characteristics

B

Serial Interconnections

Interface Characteristics

In specifying parameters for serial binary data interchange between DTE and DCE devices, the EIA-530 standard assumes the use of balanced lines, except for the Remote Loopback, Local Loopback, and Test Mode lines, which are single-ended. Balanced-line data interchange is generally employed in preference to unbalanced-line data interchange where any of the following conditions prevail:

❏The interconnection cable is too long for effective unbalanced operation.

❏The interconnection cable is exposed to extraneous noise sources that may cause an unwanted voltage in excess of ± 1V measured

differentially between the signal conductor and circuit ground at the load end of the cable, with a 50Ω resistor substituted for the transmitter.

❏It is necessary to minimize interference with other signals.

❏Inversion of signals may be required (for example, plus polarity MARK to minus polarity MARK may be achieved by inverting the cable pair).

EIA-530 interface transmitter and receiver parameters applicable to the MVME2603/2604 are listed in Table B-5and Table B-6.

Table B-5. EIA-530 Interface Transmitter Characteristics

Parameter	Value		Unit
	Minimum Maximum
Differential output voltage (absolute, with 100Ω	2.0		V
load)
Open circuit differential voltage output		6.0	V
(absolute)
Output offset voltage (with 100Ω load)	2.0		V
Short circuit output current (for any voltage		± 180	mA
between −7V and +7V)
Power off output current (for any voltage between		± 100	μA
−7V and +7V)
Output transition time (with 100Ω, 15pF load)		15	ns

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