Pin Description

QSFP56 Pin Description

The transceiver’s pin assignment is SFF-8679 compliant.

Pin	Symbol	Description	Pin	Symbol	Description
1	GND	Ground	20	GND	Ground
2	Tx2n	Transmitter Inverted Data Input	21	Rx2n	Receiver Inverted Data Output
3	Tx2p	Transmitter Non-Inverted Data Input	22	Rx2p	Receiver Non-Inverted Data Output
4	GND	Ground	23	GND	Ground
5	Tx4n	Transmitter Inverted Data Input	24	Rx4n	Receiver Inverted Data Output
6	Tx4p	Transmitter Non-Inverted Data Input	25	Rx4p	Receiver Non-Inverted Data Output
7	GND	Ground	26	GND	Ground
8	ModSelL	Module Select	27	ModPrsL	Module Present
9	ResetL	Module Reset	28	IntL	Interrupt
10	Vcc Rx	+3.3 V Power supply receiver	29	Vcc Tx	+3.3 V Power supply transmitter
11	SCL	2-wire serial interface clock	30	Vcc1	+3.3 V Power Supply
12	SDA	2-wire serial interface data	31	LPMode	Low Power Mode
13	GND	Ground	32	GND	Ground
14	Rx3p	Receiver Non-Inverted Data Output	33	Tx3p	Transmitter Non-Inverted Data Input
15	Rx3n	Receiver Inverted Data Output	34	Tx3n	Transmitter Inverted Data Input
16	GND	Ground	35	GND	Ground
17	Rx1p	Receiver Non-Inverted Data Output	36	Tx1p	Transmitter Non-Inverted Data Input
18	Rx1n	Receiver Inverted Data Output	37	Tx1n	Transmitter Inverted Data Input
19	GND	Ground	38	GND	Ground

This head end of the MCP7F60 is QSFP-Double Density and QSFP56 and the ‘tails’ are QSFP56. This means that the control signals shown in the pad layout and the pin assignments have the following functions:

Name	Function	Description
ModPrsL	Output, asserted low	Pull-up by host when no transceiver/cable is present. Connected to ground inside the transceiver. Hence, asserted low when a transceiver/cable is plugged in.
ModSelL	Input, asserted Low	Module Select input pin, terminated high in the module. Only when held low by the host, the module responds to 2-wire serial communication commands. The ModSelL enables multiple modules to share a single 2-wire interface bus.
ResetL	Input, asserted Low	Reset input pin, pulled high in the module. A low level on the ResetL pin for longer than the minimum length initiates a module reset. When de-asserted the transceiver starts its initialization procedure. See the CMIS specification.
LPMode	Input, asserted high	Low Power Mode input, pulled up inside the module. Hardware control signal for forcing the transceiver into low-power state. Can be overwritten by low-power mode command.
IntL	Output, asserted low	Interrupt Low is an open-collector output, terminated high in the host system. A “Low” indicates a possible module operational fault or a status critical to the host system, e.g. temperature alarm. The host identifies the source of the interrupt using the 2-wire serial interface.

Diagnostics and Other Features

The transceiver complies with the SFF-8665 specification and has the following key features:

Physical layer link optimization:

Programmable Tx input equalization
Programmable Rx output amplitude
Programmable Rx output pre-emphasis
Tx/Rx CDR control
by default enabled for 200 Gb/s operation.

Digital Diagnostic Monitoring (DDM):

Rx receive optical power monitor for each lane
Tx transmit optical power monitor for each lane
Tx bias current monitor for each lane
Supply voltage monitor
Transceiver case temperature monitor
Warning and Alarm thresholds for each DDM function (not user changeable)

Other SFF-8636 functions and interrupt indications:

Tx & Rx LOS indication
Tx & Rx LOL indication
Tx fault indication

LOS, LOL, and Tx Fault status flags can be read via the two-wire management interface and are jointly transmitted via the IntL output pin. Relevant advertisement, threshold, and readout registers are found in the CMIS 4.0 MSA.

On This Page

Pin Description

QSFP56 Pin Description

QSFP56 Module Pad Layout

Control Signals

Diagnostics and Other Features