Pin Descriptions

QSFP-DD Pad Description

The head end of the MCP7F80 cable has the pad assignment shown below, which is compliant with the QSFP-DD Hardware Specification ‎[2].

Pin	Symbol	Description	Pin	Symbol	Description
1	GND	Ground	39	GND	Ground
2	Tx2n	Transmitter Inverted Data Input	40	Tx6n	Transmitter Inverted Data Input
3	Tx2p	Transmitter Non-Inverted Data Input	41	Tx6p	Transmitter Non-Inverted Data Input
4	GND	Ground	42	GND	Ground
5	Tx4n	Transmitter Inverted Data Input	43	Tx8n	Transmitter Inverted Data Input
6	Tx4p	Transmitter Non-Inverted Data Input	44	Tx8p	Transmitter Non-Inverted Data Input
7	GND	Ground	45	GND	Ground
8	ModSelL	Module Select	46	Reserved
9	ResetL	Module Reset	47	VS1	Module Vendor Specific 1
10	VccRx	+3.3V Power Supply Receiver	48	VccRx1	+3.3V Power Supply Receiver
11	SCL	2-wire Serial Interface Clock	49	VS2	Module Vendor Specific 2
12	SDA	2-wire Serial Interface Data	50	VS3	Module Vendor Specific 3
13	GND	GND	51	GND	Ground
14	Rx3p	Receiver Non-Inverted Data Output	52	Rx7p	Receiver Non-Inverted Data Output
15	Rx3n	Receiver Inverted Data Output	53	Rx7n	Receiver Inverted Data Output
16	GND	Ground	54	GND	Ground
17	Rx1p	Receiver Non-Inverted Data Output	55	Rx5p	Receiver Non-Inverted Data Output
18	Rx1n	Receiver Inverted Data Output	56	Rx5n	Receiver Inverted Data Output
19	GND	Ground	57	GND	Ground
20	GND	Ground	58	GND	Ground
21	Rx2n	Receiver Inverted Data Output	59	Rx6n	Receiver Inverted Data Output
22	Rx2p	Receiver Non-Inverted Data Output	60	Rx6p	Receiver Non-Inverted Data Output
23	GND	Ground	61	GND	Grounds
24	Rx4n	Receiver Inverted Data Output	62	Rx8n	Receiver Inverted Data Output
25	Rx4p	Receiver Non-Inverted Data Output	63	Rx8p	Receiver Non-Inverted Data Output
26	GND	Ground	64	GND	Ground
27	ModPrsL	Module Present	65	NC
28	IntL	Interrupt	66	Reserved
29	VccTx	+3.3V Power Supply Transmitter	67	VccTx1	+3.3V Power Supply Transmitter
30	Vcc1	+3.3V Power Supply	68	Vcc2	+3.3V Power Supply
31	LPMode	Low Power Mode	69	Reserved
32	GND	Ground	70	GND	Ground
33	Tx3p	Transmitter Non-Inverted Data Input	71	Tx7p	Transmitter Non-Inverted Data Input
34	Tx3n	Transmitter Inverted Data Input	72	Tx7n	Transmitter Inverted Data Input
35	GND	Ground	73	GND	Ground
36	Tx1p	Transmitter Non-Inverted Data Input	74	Tx5p	Transmitter Non-Inverted Data Input
37	Tx1n	Transmitter Inverted Data Input	75	Tx5n	Transmitter Inverted Data Input
38	GND	Ground	76	GND	Ground

QSFP-DD Module Pad Layout

SFP56 Pin Description

The 50G ‘tails’ of the MCP7F80 cable are compliant with the SFF-8431 specifications. The connectors have the pin assignment shown below.

Pin	Symbol	Description
1	VeeT	Module Transmitter Ground
2	Tx_Fault	Module Transmitter Fault. Connected to GND.
3	Tx_Disable	Not used. Connected to 3.3V
4	SDA	2-wire Serial Interface Data Line
5	SCL	2-wire Serial Interface Clock
6	Mod_ABS	Module Absent. Grounded within the module
7	RS0	Rate Select 0, optionally controls SFP+ module receiver. Pulled down to GND. Not used.
8	Rx_LOS	Not used. Connected to GND.
9	RS1	Rate Select 1, optionally controls SFP+ module transmitter. Not used.
10	VeeR	Module Receiver Ground
11	VeeR	Module Receiver Ground
12	RD-	Receiver Inverted Data Output
13	RD+	Receiver Non-Inverted Data Output
14	VeeR	Module Receiver Ground
15	VccR	Module Receiver Power Supply
16	VccT	Module Transmitter Power Supply. Connected to 3.3V.
17	VeeT	Module Transmitter Ground
18	TD+	Transmitter Non-Inverted Data Input. AC coupled
19	TD-	Transmitter Inverted Data Input. AC coupled
20	VeeT	Module Transmitter Ground

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QSFP-DD Pad Description

QSFP-DD Module Pad Layout

SFP56 Pin Description

SFP+ Module Pad Layout