Ascent Communication Technology

1.25G SFP BX 3155 3 km

Ascent’s SFP BIDI 1.25G 3 km transceiver is a compact and flexible optical interface solution designed for switches, routers, servers, and other network platforms. Supporting data rates up to 1.25 Gb/s, the module complies with the SFP Multi-Source Agreement (MSA) and provides reliable performance for bi-directional single-fiber applications. The module integrates a standard TTL-level TX Disable control as well as digital I²C-based management, enabling flexible laser shutdown and real-time monitoring of device status. A dedicated TX Fault indication helps identify potential laser degradation, ensuring stable long-term operation in critical links. For enhanced system reliability, a Loss of Signal (LOS) output is provided to detect insufficient receiver optical power or partner-device link issues. All key alarms and status parameters—including LOS, link state, disable status, and fault notifications—can be accessed through the module’s integrated digital diagnostics interface.

· Up to 1.25Gb/s Data Links

· A type:1310nm FP Tx/1550nm Rx

· B type:1550nm FP Tx/1310nm Rx

· Hot-Pluggable SFP footprint

· Single LC for Bi-directional Transmission

· Built-in digital diagnostic functions

· Up to 3km on 9/125μm SMF

· Single +3.3V Power Supply

· Operating Temperature:

Standard: 0°C to +70°C

Industrial: -40°C to +85°C

· Very low EMI and excellent ESD protection

· RoHS compliant and Lead Free

Absolute Maximum Ratings

Parameter Operating Case Temperature	Symbol T_C	Min. 0	Typ.	Max. +70	Unit °C	Note Commercial
		-40		+85	°C	Industrial
Power Supply Voltage	Vcct, R	-0.5		4	V
Relative Humidity	RH	0		85	%

Optical Characteristics(TOP = T_c, V_CC = 3.135 to 3.465 Volts)

Parameter	Symbol	Min.	Typ.	Max.	Unit	Note
Transmitter
Center Wavelength	λ_c	1290	1310	1330	nm	SFP-LP-3155-03 1
						SFP-LP-3155-03A 1
	λ_c	1530	1550	1570	nm	SFP-LP-5531-03 1
						SFP-LP-5531-03A 1
Spectral Width	σ			3	nm
Optical Output Power	P_out	-14		-7	dBm	2
Optical Rise/Fall Time	tr / tf			260	ps	3
Extinction Ratio	ER	9			dB
Deterministic Jitter Contribution	TXΔDJ			56.5	ps	4
Total Jitter Contribution	TXΔTJ			0.284	ps	3
Eye Mask for Optical Output	Compliant with Eye Mask Defined in IEEE 802.3 standard
Relative Intensity Noise	RIN			-120	dB/Hz
Receiver
Optical Input Wavelength	λ_c	1530	1550	1570	nm	SFP-LP-3155-03
						SFP-LP-3155-03A
	λ_c	1290	1310	1330	nm	SFP-LP-5531-03
						SFP-LP-5531-03A
Receiver Overload	P_ol	-3			dBm	5.6
RX Sensitivity	Sen			-19	dBm	5.6
RX_LOS Assert	LOSA	-35			dBm
RX_LOS Deassert	LOSD			-20	dBm
RX_LOS Hysteresis	LOSH	0.5			dB
General Characteristics
Data Rate
Data Rate	BR		1.25		Gbps
Bit Error Rate	BER			10^-12
Max. Supported Link Length on 9/125μm SMF@1.25G	LMAX		3		km	7
Total System Budget	LB	12			dB	8

Notes:

1. The optical power is launched into SMF.

2. 20 to 80%.

3. Contributed total jitter is calculated from DJ and RJ measurements using TJ = RJ + DJ. Contributed RJ is calculated for 1x10^-12 BER by multiplying the RMS jitter (measured on a single rise or fall edge) from the oscilloscope by 14. Per FC-PI, the actual contributed RJ is allowed to increase above its limit if the actual contributed DJ decreases below its limits, as long as the component output DJ and TJ remain within their specified FC-PI maximum limits with the worst case specified component jitter input.

4. Measured with PRBS 2^7-1 at 10^-12 BER.

Electrical Characteristics (TOP = T_c, V_cc = 3.135 to 3.465 Volts)

Parameter	Symbol	Min.	Typ.	Max.	Unit	Notes
Supply Voltage	V_cc	3.14	3.30	3.47	V
Supply Current	I_cc			300	mA
Inrush Current	I_surge			Icc+30	mA
Maximum Power	P_max			1.0	mW
Transmitter
Input Differential Impedance	R_in	90	100	110
Single Ended Data Input Swing	V_in,PP	250		1200	mVp-p
Transmit Disable Voltage	VD	Vcc - 1.3		Vcc	V	2
Transmit Enable Voltage	VEN	Vee		Vee+ 0.8	V
Transmit Disable Assert Time	T_dessert			10	us
Receiver
Single Ended Data Output Swing	V_out,_pp	300		800	mv	3
Data Output Rise Time	tr			1300	ps	4
Data Output Fall Time	tf			1300	ps	4
LOS Fault	V_losfault	V_cc – 0.5		V_{CC_host}	V	5
LOS Fault	V_{los norm}	V_ee		V_ee+0.5	V	5
Power Supply Rejection	PSR	100			mVpp	6
Deterministic Jitter Contribution	RXΔDJ			51.7	ps	7
Total Jitter Contribution	RXΔTJ	100			ps

Notes:

1. AC coupled.

2. Or open circuit.

3. Into 100 ohm differential termination.

4. LOS is LVTTL. Logic 0 indicates normal operation; logic 1 indicates no signal detected.

5. All transceiver specifications are compliant with a power supply sinusoidal modulation of 20Hz to 1.5MHz up to specified value applied through the power supply filtering network shown on page23 of the Small Form-factor Pluggable (SFP) Transceiver Multi-Source Agreement (MSA), September 14, 2000.
6. Measured with DJ-free data input signal. In actual application, output DJ will be the sum of input DJ and . DJ.