01.08.28 ♦ Features • Up to 3 Gb/s high speed operation • Positive thermal coefficient of modulation current • Differential ECL compatible interface • -5.2 V single power supply • Up to 50 mA p-p modulation current • Up to 50 mA bias current • Maximum bias current preset control • Low-cost 18-terminal LCC package F0513005L 3 Gb/s NRZ Data Rate Laser Diode Driver ♦ Applications • Laser diode driver of an optical transmitter circuit up to 3 Gb/s ♦ Functional Description The F0513005L is a high performance GaAs integrated laser diode driver for use in an optical transmitter circuit up to 3 Gb/s NRZ data rate. The F0513005L typically specifies rise time and fall time of 140 psec (10 % - 90 %). It features single -5.2 V supply operation, 1 to 50 mA presettable bias current and up to 50 mA modulation current while dissipating 650 mW is typical. A choice of three packages are available to match various application requirements: an 18-terminal leadless chip carrier (LCC) called F0513005L, an 18-lead metalbased flat package (MFP) called F0513005M, and a 20-lead plastic-molded QFP package called F0513005S. F0513005L 3 Gb/s Laser Diode Driver ♦ Absolute Maximum Ratings Ta = 25 °C, unless specified Parameter Symbol Value Units Supply Voltage VSS - 7 to 0.5 V Power Dissipation Pdis 1 W VIN1, VIN2 -3 to 0.5 V VOUT1, VOUT2 -3 to 0.5 V Modulation Current Control Voltage VM VSS to VSS+1.3 V Maximum Bias Current Setting Voltage VB VSS to VSS+1 V VAPC1,VAPC2 -3 to 0.5 V Tstg -55 to +125 °C Ta -0 to +70 °C Input Voltage Output Voltage APC Voltage Storage Temperature Ambient Operating Temperature ♦ Recommended Operating Conditions Ta = 25 °C, VSS = - 5.2 V, unless specified Value Parameter Symbol Units Min. Typ. Max. Supply Voltage VSS -5.5 -5.2 -5.0 V Output Voltage VOUT1, VOUT2 -2.0 -1.0 0 V Ta 0 25 70 °C Ambient Operating Temperature F0513005L 3 Gb/s Laser Diode Driver ♦ Electrical Characteristics Ta = 25 °C, VSS = - 5.2 V, unless specified Value Parameter Circuit Current (1) Input Voltage Symbol Test Conditions Typ. Max. - 75 110 mA -0.9 - -0.7 V -1.9 - -1.7 V -150 - 150 µA IMMAX VIN1 =-1.7V, VIN2 =-0.9V VAPC1 =-2.5 V, VAPC2 =0V VM =-3.9V, VB =-5.2V 50 - - mA IMMIN VIN1 =-1.7V, VIN2 =-0.9V VAPC1 =-2.5 V, VAPC2 =0V VM =-2.5V, VB =-4.2V - - 1 mA IMTC IM =25 to 50mA (Ta= 25° C) Ta = 0 to 70° C 0 - 0.6 %/° C 50 - - mA VIN1 =-0.9V, VIN2 =-1.7V VAPC1 =-2.5V, VAPC2 =-0V VM =-5.2V, VB =-5.2V - - 1 mA ISS VIH VM =-5.2V, VB=-5.2V Differential Mode VIL Input Current IIN1,IIN2 Modulation Current IM Thermal Coefficient(2) Units Min. IBMAX VIN1,VIN2 =-1.9V VIN1 =-0.9V, VIN2 =-1.7V VAPC1 =0V, VAPC2 =-2.5V VM =-5.2V, VB =-4.2V Bias Current IBMIN Rise Time tr RL = 25Ω 10% - 90% - - 200 ps Fall Time tf RL = 25Ω 10% - 90% - - 200 ps (1) except modulation current (2) IMTC = 100× [ IM (Ta = 70 °C) - IM (Ta = 0 °C) ] / IM (Ta = 25 °C) / 70 NOTES: 1. Modulation circuit on: VIN1 = - 1.7 V, VIN2 = - 0.9 V 2. Modulation circuit off: VIN1 = - 0.9 V, VIN2 = - 1.7 V 3. Bias circuit on: VAPC1 = 0 V, VAPC2 = - 2.5 V 4. Bias circuit off: VAPC1 = - 2.5 V, VAPC2 = 0 V F0513005L 3 Gb/s Laser Diode Driver ♦ Block Diagram GND VIN1 VIN2 OUT1 OUT2 GND + VAPC2 - VAPC1 VSS VSS VM Input Buffer VB Switching Section Bias Setting Section ♦ Pin Assignments (Bottom View) 12 13 14 15 11 17 18 1 10 9 8 16 2 7 6 5 No.1 LEAD IDENTIFIER 4 3 Level Shifter ♦ Pin Descriptions 1 OUT1 Output 2 3 NC VAPC1 No Connection APC Signal Input 4 VB Maximum Bias Current (IBMAX )Setting Voltage 5 6 VSS GND Supply Voltage Supply Voltage 7 VM Modulation Current Control Voltage 8 9 VAPC2 NC APC Reference Voltage No Connection 10 OUT2 Output 11 12 NC VIN2 No Connection Differential Mode Input 13 GND Supply Voltage 14 15 NC NC No Connection No Connection 16 VSS Supply Voltage 17 18 VIN1 GND Differential Mode Input Supply Voltage F0513005L 3 Gb/s Laser Diode Driver ♦ Test Circuits (1) DC Characteristics OUT1 OUT2 VIN1 VAPC1 VIN2 F0513005L VAPC2 VB VM GND VSS 4400pF -5.2V (2) AC Characteristics 50Ω 25Ω Sampling Oscilloscope OUT1 Pulse Pattern Generrator OUT2 VIN1 VAPC1 VIN2 F0513005L VAPC2 VB VM 50Ω 50Ω GND VSS 4400pF -5.2V F0513005L 3 Gb/s Laser Diode Driver ♦ Typical DC Characteristics (1) Switching characteristics 100 VM=-3.9V VM=-4.2V 50 VM=-4.5V 0 -1.8 (b) Output Current Switching Output Current IOUT (mA) Modulation Current IM (mA) (a) Modulation Current Switching -1.3 100 VM=-4.2V 50 0 -1.8 -0.8 Input Voltage VIN1(V) (VB=-5.2V, VAPC1=-2.0V,VAPC2=-0V) Maximum Bias Current IBMAX (mA) Modulation Current IM (mA) -1.3 -0.8 (b) Maximum Bias Current ns VB 100 50 -4.5 VM=-4.5V Input Voltage VIN1(V) (VB=-5V, VAPC1=-1.3V,VAPC2=-1.3V) (a) Modulation Current vs VM 0 -5.5 VM=-3.9V -3.5 100 50 0 -5.5 -4.7 -4.2 Control Voltage VM (V) Control Voltage VB (V) (VB=-5.2V, VAPC1=-2.0V, VAPC2=0V) (VIN1=-1.8V, VIN2=-0.8V) (VM=-5.2V, VAPC1=0V, VAPC2=-2.0V) (VIN1=-0.8V, VIN2=-1.8V) F0513005L 3 Gb/s Laser Diode Driver (2) Bias control by APC voltage (a) IBMAX=20mA (b) IBMAX=50mA 50.0 5.0/div VAPC2(V) -3.0 -2.5 -2.0 0.0 -3.0 -1.5 -1.0 -0.5 0.3/div Bias Current IB (mA) Bias Current IB (mA) 50.0 VAPC2(V) -3.0 -2.5 0 0.3/div APC Voltage VAPC1 (V) (VM=-5.2V, VB=-5.2V) (VAPC2=-3.0V to 0V, step 0.5V) (VM=-5.2V, VB=-5.2V) (VAPC2=-3.0V to 0V, step 0.5V) (3) Dependence on modulation current on the ambient temperature 80 IM (mA) 60 40 20 20 0 -1.0 5.0/div APC Voltage VAPC1 (V) 0 -40 -1.5 -0.5 0.0 -3.0 0.0 -2.0 20 40 60 Temperature (°C) (VIN1=-1.8V, VIN2=-0.8V) (VB=-5.2V, VAPC1=-2.0V, VAPC2=0V) 80 0.0 F0513005L 3 Gb/s Laser Diode Driver ♦ Typical AC Characteristics (1) Eye diagrams for pseudo-random data response of electrical output Ta = 25 °C, VSS = - 5.2 V, VIN = 0.8 Vp-p, RL = 25 Ω 20 mV/div (a) 1 Gb/s NRZ (PRBS 223-1) 200 psec/div 20 mV/div (b) 3 Gb/s NRZ (PRBS 223-1) 50 psec/div F0513005L 3 Gb/s Laser Diode Driver ♦ Application Notes (1) Example of circuit block diagram to drive laser diode Sampling Oscilloscope O/E Converter 10Ω 25Ω OUT1 Pulse Pattern Generator OUT2 VIN1 VAPC1 VIN2 F0513005L VAPC2 VB VM 50Ω 50Ω GND VSS 4400pF -5.2V NOTE : The 10Ω and 25Ω resistors in series with OUT1 and OUT2 respectively are damping resistors. Their values are selected to minimize ringing caused by the impedance mismatch to the laser diode. These values may change depending upon the type of laser diode used. (2) Eye diagrams for 2.4 Gb/s NRZ pseudo-random data response of optical output PRBS 223-1, Ta = 25 °C, VSS = - 5.2 V, Vin = 0.8 Vp-p, RL = 25 Ω *Laser Diode: Mitsubishi FU-63SDF F0513005L 3 Gb/s Laser Diode Driver (3) Example of APC circuit .027µ LD monitor PD 200 50 50 50 -4.4V .027µ 10k * 10k .027µ 10k 240k - * -2.7V + -2.4V + - * -1.5V + 10 13.5k 12.5k VIN2 DATA .027µ 1.1k - 12k -5.2V OUT1 OUT2 VIN1 VAPC1 DATA .027µ 14k 7.5k 18.5k -5.2V -5.2V *LM324 VAPC2 F0513005L VM VB GND VSS -4.4V -1.5V .027µ .027µ 1.6k -5.2V 8.8k 4400p -5.2V 8.8k 1.6k -5.2V 7.5k 18.5k -5.2V (4) Example of evaluation board NOTE: The open circles indicate soldering positions for coaxial cables. Islands A and B are termination resistors bias points. When driven from Picologic, they should be connected to -2 V. Otherwise, they may be connected to ground. 3 Gb/s Laser Diode Driver F0513005L ♦ General Description Bias current and modulation current are very important electrical characteristics in a laser diode. A center value of the driving current of a laser diode is bias current, which is designed to be presettable ranging from 1 to 50 mA by a controlled voltage of VB terminal according to the threshold current of an employed laser diode and the application. An optical output power is proportional to an amplitude of the driving current of a laser diode called modulation current which can be controlled from 1 to 50 mA by a voltage of VM terminal. Protection against laser thermal runaway is provided by auto power control. VAPC terminal is used to control the bias current setting negative feedback, monitoring the optical output power by PIN photo diode. ♦ Positive Temperature Characteristics The most remarkable feature of the F0513005L, which can not be found in other IC's, is the positive temperature characteristics of the modulation current designed to be +0.5 %/°C. Emission efficiency in typical laser diodes exhibits negative temperature characteristics; their optical output decreases with increasing ambient temperature. In the case of multiquantum well (MQW) laser diodes, which is the focus of keen interest, the temperature coefficient of -0.5 %/°C is reported. The F0513005L can successfully compensate the temperature fluctuation of the optical output power, providing a stable extinction ratio. If a driver circuit does not have a positive temperature characteristic in the modulation current, the bias current increases above the threshold current at higher temperature, resulting in degradation of the extinction ratio. It is not impossible to achieve this kind of compensation by external circuits; it is, however, unrealistic owing to inevitably troublesome tuning. ♦ User-friendly Design The F0513005L features a user-friendly design for system designers, permitting a single +5 V power supply operation. A differential ECL compatible input for direct control from ECL or conventional GaAs logic IC's is provided. Two unique auto power controls (VAPC1, VAPC2) permit modulation of the bias current control setting as a mechanism to protect the laser diode against thermal runaway. The APC controls may be modulated at rates up to 100 MHz. 3 Gb/s Laser Diode Driver F0513005L ♦ Packaging The F0513005L is in an 18-terminal ceramic LCC package about 300 mil square with the lead pitch of 50 mil, achieving miniaturization and low cost. It is convenient for designers to miniaturize the circuit area in the PCB owing to the leadless package with small dimension. The F0513005M packaged in an 18-lead ceramic MFP about 300 mil square with the lead pitch of 40 mil is also available as another choice for this device, allowing to enhance the flexibility of assembling design. It was originally developed by SEI to improve RF performance and heat radiation. Compared with the LCC, the ground potential is stabler at microwave frequency range and the thermal resistivity is smaller due to the metalbased bottom structure made from CuW (an alloy of copper and tungsten) with a high thermal conductivity. The electrical characteristics of both IC's are almost equal but the system performance depends on the assembling design. The F0513005M is more suitable for application requiring very excellent eye pattern performance and severe thermal stability. ♦ Precautions Owing to their small dimensions, the GaAs FET's from which the F0513005L is designed are easily damaged or destroyed if subjected to large transient voltages. Such transients can be generated by power supplies when switched on if not properly decoupled. It is also possible to induce spikes from static-electricity-charged operations or ungrounded equipment. F0513005L 3 Gb/s Laser Diode Driver ♦ Package Drawings 6.35±0.2 0.41 TYP 0.60 TYP 2.30 TYP 0.97 TYP 0.80 TYP 6.35±0.2 0.22-R TYP 1.27 TYP Notes: (1) All dimensions in millimeters. (2) Package is made of ceramic. (3) Leads are Ni and Au plated copper. (4) Base metal is copper tungsten. Electron Device Department