SNLS484 Data sheet

6.9 RGMII Timing

PARAMETER		TEST CONDITIONS⁽⁵⁾	MIN	NOM	MAX	UNIT
T_skewT	Data to Clock output Skew (at Transmitter)	See ⁽¹⁾	–500	0	500	ps
T_skewR	Data to Clock input Skew (at Receiver)	See ⁽¹⁾	1	1.8	2.6	ns
T_setupT	Data to Clock output Setup (at Transmitter – internal delay)	See ⁽⁴⁾	1.2	2		ns
T_holdT	Clock to Data output Hold (at Transmitter – internal delay)	See ⁽⁴⁾	1.2	2		ns
T_setupR	Data to Clock input Setup (at Reciever – internal delay)	See ⁽⁴⁾	1	2		ns
T_holdR	Clock to Data input Hold (at Receiver – internal delay)	See ⁽⁴⁾	1	2		ns
T_cyc	Clock Cycle Duration	See ⁽²⁾	7.2	8	8.8	ns
Duty_G	Duty Cycle for Gigabit	See ⁽³⁾⁽⁷⁾	45	50	55%
Duty_T	Duty Cycle for 10/100T	See ⁽³⁾⁽⁷⁾	40	50	60%
T_R	Rise Time (20% to 80%)				0.75	ns
T_F	Fall Time (20% to 80%)				0.75	ns
T_TXLAT	RGMII to MDI Latency	See ⁽⁶⁾		88		ns
T_RXLAT	MDI to RGMII Latency	See ⁽⁶⁾		288		ns

(1) When operating without RGMII internal delay, the PCB design requires clocks to be routed such that an additional trace delay of greater than 1.5ns is added to the associated clock signal.

(2) For 10Mbps and 100Mbps, Tcyc will scale to 400ns ± 40ns and 40ns ± 4ns.

(3) Duty cycle may be stretched or shrunk during speed changes or while transitioning to a received packet’s clock domain as long as minimum duty cycle is not violated and stretching occurs for no more that three Tcyc of the lowest speed transitioned between.

(4) Device may operate with or without internal delay.

(5) Specified by production test, characterization, or design.

(6) Operating in 1000Base-T .

(7) Duty cycle values are defined in percentages of the nominal clock speed. For example, the minimum Gigabit RGMII clock pulse duration is 45 % of 8ns.

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Orderable Information

6.9 RGMII Timing