DS1842A 19-4994 Rev 1 9/11 76V, APD, Dual Output Current Monitor General Description Features The DS1842A integrates the discrete high-voltage 76V Maximum Boost Voltage components necessary for avalanche photodiode Current Monitor with a Wide 1A to 2mA Range, (APD) bias and monitor applications. A precision volt- Fast 50ns Time Constant, and 10:1 and 5:1 Ratio age-divider network is used in conjunction with an external DC-DC controller and FET to create a boost 2mA Current Clamp with External Shutdown DC-DC converter. A current clamp limits current Precision Voltage Feedback through the APD and also features an external shut- Multiple External Filtering Options down. The precision voltage-divider network is provid- ed for precise control of the APD bias voltage. The 3mm x 3mm, 14-Pin TDFN Package with Exposed Pad device also includes a dual current mirror to monitor the APD current. Ordering Information PART TEMP RANGE PIN-PACKAGE Applications DS1842AN+ -40C to +85C 14 TDFN-EP* APD Biasing DS1842AN+T&R -40C to +85C 14 TDFN-EP* GPON ONU and OLT +Denotes a lead(Pb)-free/RoHS-compliant package. T&R = Tape and reel. *EP = Exposed pad. Typical Application Circuit 3.3V FBIN C BULK DS1842A MIRIN R 1 PWM CURRENT MIRROR FBOUT ADC MIR1 R 2 CLAMP CURRENT GPIO LIMIT MIR2 EXTERNAL MONITOR EP GND MIROUT ROSA DS4830 APD TIA ADC Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLE76V, APD, Dual Output Current Monitor ABSOLUTE MAXIMUM RATINGS Voltage Range on CLAMP Continuous Power Dissipation (TA = +70C) Relative to GND...................................................-0.3V to +12V TDFN (derate 24.4mW/C above +70C).................1951.2mW Voltage Range on MIRIN, MIROUT, FBIN Operating Junction Temperature Range...........-40C to +150C MIR1, and MIR2 Relative to GND........................-0.3V to +80V Storage Temperature Range .............................-55C to +135C Voltage Range on FBOUT Relative to GND ..........-0.3V to +6.0V Lead Temperature (soldering, 10s) .................................+300C Soldering Temperature (reflow) .......................................+260C 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. PACKAGE THERMAL CHARACTERISTICS (Note 1) TDFN Junction-to-Ambient Thermal Resistance ( ) ............41C/W JA Junction-to-Case Thermal Resistance ( ) ...................8C/W JC Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. ELECTRICAL CHARACTERISTICS (T = -40C to +85C, unless otherwise noted.) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS CLAMP Voltage V 0 11 V CLAMP CLAMP Threshold V 1.25 1.8 2.35 V CLT CLAMP = low 1.8 2.75 3.85 mA Maximum MIROUT Current I MIROUT CLAMP = high 10 A MIR1 to MIROUT Ratio K 15V < V < 76V, I > 1A 0.096 0.100 0.104 A/A MIR1 MIRIN MIROUT MIR2 to MIROUT Ratio K 15V < V < 76V, I > 1A 0.192 0.200 0.208 A/A MIR2 MIRIN MIROUT MIR1, MIR2 Rise Time t (Note 2) 30 ns RC (20%/80%) Shutdown Temperature T (Note 3) +150 C SHDN Hysteresis Temperature T (Note 3) 5 C HYS Leakage on CLAMP I -1 +1 A IL Resistor-Divider Ratio (R /R) K T = +25C, V = 76V 59.5 60.25 1 2 R A FBIN Resistor-Divider Tempco 50 ppm/C Resistor-Divider End-to-End R T = +25C, V = 76V 308 385 481 k RES A FBIN Resistance Note 2: Rising MIROUT transition from 10A to 1mA V = 40V, 2.5k load. MIRIN Note 3: Not production tested. Guaranteed by design. 2 DS1842A