MAX3795 19-3387 Rev 0 8/04 1Gbps to 4.25Gbps Multirate VCSEL Driver with Diagnostic Monitors General Description Features The MAX3795 is a high-speed VCSEL driver for small- Supports All SFF-8472 Digital Diagnostics form-factor (SFF) and small-form-factor pluggable (SFP) 3.3V 10% Single Supply fiber optic transmitters. It contains a bias generator, a laser modulator, and comprehensive safety features. 2mA to 15mA Modulation Current The automatic power control (APC) adjusts the laser 1mA to 15mA Bias Current bias current to maintain average optical power over changes in temperature and laser properties. The dri- 52ps Transition Time ver accommodates common-cathode and differential 8.4ps Deterministic Jitter configurations. Optional Peaking Current to Improve VCSEL Edge The MAX3795 operates up to 4.25Gbps. It can switch up to 15mA of laser modulation current and source up Speed to 15mA of bias current. Adjustable temperature com- Supports Common-Cathode and Differential pensation is provided to keep the optical extinction Configuration ratio within specifications over the operating tempera- ture range. The MAX3795 interfaces with the Dallas Safety Circuits Compliant with SFF and SFP DS1856/DS1859 to meet SFF-8472 timing and diagnos- MSAs tic requirements. The MAX3795 accommodates various Pin Compatible to MAX3740A VCSEL packages, including low-cost TO-46 headers. The MAX3795 safety circuit detects faults that could cause hazardous light levels and disables the VCSEL Ordering Information output. The safety circuits are compliant with SFF and SFP multisource agreements (MSAs). PART TEMP RANGE PIN-PACKAGE The MAX3795 is available in a compact 4mm 4mm, MAX3795ETG -40C to +85C 24 Thin Q FN ( 4m m x 4mm ) 24-pin thin QFN package and operates over the -40C MAX3795ETG+ -40C to +85C 24 Thin Q FN ( 4mm x 4mm ) to +85C temperature range. The MAX3795 is pin-for- pin compatible with the MAX3740A and is available in +Denotes lead-free package. lead-free packages. Pin Configuration Applications Multirate (1Gbps to 4.25Gbps) SFP/SFF Modules TOP VIEW Gigabit Ethernet Optical Transmitters Fibre-Channel Optical Transmitters GND 1 18 BIAS TX DISABLE 2 17 BIASSET IN+ 3 16 V CC MAX3795 IN- 4 15 OUT+ FAULT 5 14 OUT- SQUELCH 6 13 GND THIN QFN (4mm x 4mm) EXPOSED PAD IS CONNECTED TO GND Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. V 7 24 PWRMON CC TC1 8 23 REF TC2 9 22 MD GND 10 21 COMP MODSET 11 20 V CC PEAKSET 12 19 BIASMON1Gbps to 4.25Gbps Multirate VCSEL Driver with Diagnostic Monitors ABSOLUTE MAXIMUM RATINGS Supply Voltage (V ) ............................................-0.5V to +4.0V Continuous Power Dissipation (T = +85C) CC A Voltage at TX DISABLE, IN+, IN-, FAULT, 24-Pin Thin QFN SQUELCH, TC1, TC2, MODSET, PEAKSET, BIASSET, (derate 20.8mW/C above +85C).................................1354mW BIAS, BIASMON, COMP, MD, REF, Storage Temperature Range .............................-55C to +150C PWRMON ...............................................-0.5V to (V + 0.5V) Lead Temperature (soldering, 10s) .................................+300C CC Voltage at OUT+, OUT-.........................(V - 2V) to (V + 1V) CC CC Current into FAULT ............................................ -1mA to +25mA Current into OUT+, OUT-....................................................60mA 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 (V = +2.97V to +3.63V, T = -40C to +85C. Typical values are at V = +3.3V, TC1 and TC2 are shorted, PEAKSET open, T = CC A CC A +25C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS SQUELCH set low, I = 2mA 35 MOD P-P TX DISABLE set low, peaking is not used I = 15mA 71 81 MOD P-P (Note 1) I CC Supply Current mA Additional current when peaking is used, 15 R = 1.18k PEAK Additional current when SQUELCH is high 5 10 I Total current when TX DISABLE is high 7 CC-SHDN FAULT OUTPUT Output High Voltage V R = 10k to 2.97V 2.4 V OH LOAD Output Low Voltage V R = 4.7k to 3.63V 0.4 V OL LOAD TX DISABLE INPUT Input Impedance R 4.7 8 10.0 k PULL Input High Voltage V 2.0 V IH Input Low Voltage V 0.8 V IL The time for I to reach I when CC CC-SHDN Power-Down Time 50 s TX DISABLE transitions high SQUELCH Squelch Threshold 25 85 mV P-P Squelch Hysteresis 6 mV P-P Time to Squelch Data (Note 3) 0.02 5.00 s Time to Resume from Squelch (Note 3) 0.02 5.00 s BIAS GENERATOR Maximum Bias Pin Voltage V Referenced to V -0.65 V BIAS-MAX CC Minimum 1 Bias Current I mA BIAS Maximum 15 5mA I 15mA -8 +8 Accuracy of Programmed Bias BIAS BIAS % Current 1mA I 5mA -12 +12 BIAS 2 MAX3795