Ascent Communication Technology

2.5G SFP 1310nm 20km

Ascent’s 2.5 Gb/s 1310 nm Small Form-Factor Pluggable (SFP) transceiver is a flexible solution as an interface for switches, routers, servers, and other optical links. The transceiver consists of five sections: the LD driver, the limiting amplifier, the digital diagnostics monitor, the 1310 nm DFB laser, and the PIN photo-detector. The module can carry data links up to 20 km in a 9/125 µm single mode fiber, and is compatible with the SFP Multi- Sourcing Agreement (MSA). The optical output of the transceiver can be disabled using a high-level TTL logic TX disable input, and the system can also be disabled via I2C. TX Fault is provided to indicate any degradation of the laser. A loss of signal (LOS) output is provided to indicate if there are any losses in the input optical signal of the receiver or if there are any problems with the link status of partner devices. The system can also obtain the LOS (or Link) / Disable / Fault information using an I2C register access.

· Operating Data Rate up to 2.5Gbps

· 1310nm DFB Laser Transmitter

· 2.5Gb/s PIN-TIA photodiode receiver

· 20km with 9/125µm SMF

· Single 3.3V Power Supply

· Hot-Pluggable SFP Footprint Duplex LC Connector Interface

· Operating Temperature 0°C ~70°C

· Compliant with SFF-8472

· Compliant with MSA SFP Specification

· Class 1 FDA and IEC60825-1 Laser Safety Compliant

Absolute Maximum Ratings

Parameter	Symbol	Min.	Max.	Unit
Storage Temperature	T_s	-40	+85	°C
Maximum Supply Voltage	V_cc	-0.5	3.6	V
Operating Relative Humidity	RH	5	85	%

Recommended Operating Conditions

Parameter	Symbol	Min.	Typ.	Max.	Unit
Operating Case Temperature	T_c	0		70	°C
Power Supply Voltage	V_cc	3.15	3.3	3.45	V
Power Supply Current	I_cc			300	mA

Optical Characteristics

Parameter	Symbol	Min.	Typ.	Max.	Unit
9µm Core Diameter SMF	L		20		km
Data Rate			2.5		Gbps
Power Budget			13		dB
Transmitter
Center Wavelength	λ_C	1260	1310	1360	nm
Spectral Width (-20dB)	∆λ			1	nm
Side Mode Suppression Ratio	SMSR	30			dB
Average Output Power*(Note1)	Pout	-5		0	dBm
Extinction Ratio*(Note2)	ER	8.2			dB
Rise/Fall Time (20% ~ 80%)	tr/tf			150	ps
Total Jitter*(Note2)	TJ			0.07	UI
Output Optical Eye	ITU-T G.957 Compliant
Pout@TX Disable Asserted	Pout			-45	dBm
Receiver
Center Wavelength	λ_C	1260		1600	nm
Receiver Sensitivity*(Note3)	Pmin			-18	dBm
Receiver Overload	Pmax	-3			dBm
LOS De-Assert	LOSD			-19	dBm
LOS Assert	LOSA	-35			dBm
LOS Hysteresis		0.5			dB

Notes:

1. Output is coupled into a 9/125um SMF.

2. Filtered, measured with a PRBS 223-1 test pattern @2.5Gbps.

3. Minimum average optical power is measured at BER less than 1E-12, with 223-1 PRBS and ER=8.2dB

Electrical Characteristics

Parameter		Symbol	Min.	Typ.	Max.	Unit	Note
Transmitter
LVPECL Inputs (Differential)		Vin	400		1600	mVpp	AC Coupled Inputs*(Note1)
Input Impedance (Differential)		Zin	85	100	115	ohms	Rin > 100 kohms @ DC
TX_Dis	Disable		2		Vcc+0.3	V
TX_Dis	Enable		0		0.8	V
TX_FAULT	Fault		2		Vcc+0.3	V
TX_FAULT	Normal		0		0.5	V
Receiver
LVPECL Outputs (Differential)		Vout	400	800	1200	mVpp	AC Coupled Outputs*(Note1)
Output Impedance (Differential)		Zout	85	100	115	ohms
TX_Disable Assert Time		t_off			10	us
RX_LOS	LOS		2		Vcc+0.3
	Normal		0		0.8
MOD_DEF (0.2)		VoH	2.5			V	With Serial ID
		VoL	0		0.5	V	With Serial ID

Note:

1. LVPECL logic, internally AC coupled.

Digital Diagnostic Functions

Parameter	Range	Unit	Accuracy	Calibration
Temperature	0 to 70	°C	±3°C	Internal / External
Voltage	3.0 to 3.6	V	±3%	Internal / External
Bias Current	0 to 70	mA	±10%	Internal / External
TX Power	-5 to 0	dBm	±3dB	Internal / External
RX Power	-18 to -3	dBm	±3dB	Internal / External