Document
19-2597; Rev 1; 5/04
3.2Gbps Compact SFP VCSEL Driver
General Description
The MAX3741 is a high-speed VCSEL driver for smallform-factor (SFF) and small-form-factor pluggable (SFP) fiber-optic LAN transmitters. It contains a bias generator, laser modulator, and peaking current option to improve VCSEL edge speed. The driver accommodates common cathode and differential configurations. The MAX3741 operates up to 3.2Gbps. It can switch up to 15mA of laser modulation current and source up to 15mA of bias current. The MAX3741 is designed to interface with a digital potentiometer and control circuitry. The MAX3741 accommodates various VCSEL packages, including low-cost TO-46 headers. The MAX3741 is available in a compact 3mm x 3mm 16-pin thin QFN package and operates over a temperature range of -40°C to +85°C. o 2mA to 15mA Modulation Current o 1mA to 15mA Bias Current o Optional Peaking Current to Improve VCSEL Edge Speed o Supports Common Cathode and Differential Configuration o 3mm × 3mm 16-Pin Thin QFN Package
Features
MAX3741
Applications
Multirate (1Gbps to 3.2Gbps) SFP/SFF Modules Gigabit Ethernet Optical Transmitters Fibre Channel Optical Transmitters
PART MAX3741ETE
Ordering Information
TEMP RANGE -40°C to +85°C PINPACKAGE 16 Thin QFN PKG. CODE T1633F-3
Typical Application Circuit
+3.3V
Pin Configuration
VCC BIAS 0.1µF IN+ IN0.1µF MAX3741 OUT+ 0.01µF OUT50Ω TX_DISABLE BIASSET MODSET BIASMON GND PEAKSET RPEAKSET 0.01µF L1*
16
15
14
13
TX_DISABLE IN+ INN.C.
BIAS 12 BIASMON 11 OUT+ 10 OUT9
GND
1 2 3 4 5 VCC 6 7 PEAKSET 8
MAX3741 3mm x 3mm
VCC
TOP VIEW
BIASSET
0.01µF
VCC
RBIASSET
RMODSET
RMON
THIN QFN
EXPOSED PAD IS CONNECTED TO GND.
THIS SYMBOL REPRESENTS A TRANSMISSION LINE OF CHARACTERISTIC IMPEDANCE Zo = 50Ω. * FERRITE BEAD, MURATA BLM18HD102SN1B
________________________________________________________________ Maxim Integrated Products
MODSET
GND
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
3.2Gbps Compact SFP VCSEL Driver MAX3741
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC) ............................................-0.5V to +5.0V Voltage at TX_DISABLE, IN+, IN-, MODSET, PEAKSET, BIASSET, BIAS, BIASMON .......-0.5V to (VCC + 0.5V) Voltage at OUT+, OUT- .........................(VCC - 2V) to (VCC + 2V) Current into OUT+, OUT- ....................................................60mA Continuous Power Dissipation (TA = +85°C) 16-Lead Thin QFN (derate 25mW/°C above +85°C) ..........2W Operating Temperature Range .......................... -40°C to +85°C Storage Temperature Range .............................-55°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VCC = +2.97V to +3.63V, TA = -40°C to +85°C. Typical values are at VCC = +3.3V, TA = +25°C, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS TX_DISABLE set low, peaking is not used (Note 1) IMOD = 2mAP-P IMOD = 15mAP-P MIN TYP 41 51 14 0.15 80 VIH VIL t_off TX_DISABLE Time t_on Input Leakage BIAS GENERATOR (Note 4) Bias Current Accuracy of Programmed Bias Current Bias Current During Disable BIASMON Gain LASER MODULATOR (Note 5) Data Input Voltage Swing Output Resistance Modulation Current VID ROUT IMOD Total differential signal Single-ended resistance at OUT+, OUTMin Max 15 250 63 2200 80 2 mVP-P Ω mAP-P IBIAS ∆IBIAS IBIAS_OFF TX_DISABLE high 0.095 0.115 Min Max 15 -8 +8 10 0.135 1 mA % µA mA/mA Time from rising edge of TX_DISABLE to IBIAS = IBIAS_OFF and IMOD = IMOD_OFF (Note 3) Time from falling edge of TX_DISABLE to IBIAS = 15mA and IMOD = 15mAP-P VCC = 0V and VTX_DISABLE = 3.3V 0.2 2 0.8 3 µs 111 25 40 µA 105 65 mA 20 1 kΩ V V MAX UNITS
Supply Current
ICC
Additional current when peaking is used (Note 2) ICC-SHDW Total current when TX_DISABLE is high
TX_DISABLE INPUT Input Impedance Input High Voltage Input Low Voltage
2
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3.2Gbps Compact SFP VCSEL Driver
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +2.97V to +3.63V, TA = -40°C to +85°C. Typical values are at VCC = +3.3V, TA = +25°C, unless otherwise noted.)
PARAMETER Programmable Peaking Current Peaking Current Duration Tolerance of Programmed Modulation Current Modulation Transition Time Deterministic Jitter Random Jitter Laser Modulation During Disable Differential Input Resistance Input Bias Voltage VIN tR, tF DJ RJ IMOD_OFF 5mAP-P ≤ IMOD ≤ 15mAP-P (Note 3) 5mAP-P ≤ IMOD ≤ 15mAP-P (Notes 3, 6) (Note 3) Differen.