MAX8520/MAX8521 19-2586 Rev 2 2/11 Smallest TEC Power Drivers for Optical Modules General Description Features The MAX8520/MAX8521 are designed to drive thermo- 2 Circuit Footprint 0.31in electric coolers (TECs) in space-constrained optical Low Profile Design modules. Both devices deliver 1.5A output current and control the TEC current to eliminate harmful current On-Chip Power MOSFETs surges. On-chip FETs minimize external components High-Efficiency Switch-Mode Design and high switching frequency reduces the size of exter- nal components. Ripple Cancellation for Low Noise The MAX8520/MAX8521 operate from a single supply and Direct Current Control Prevents TEC Current bias the TEC between the outputs of two synchronous Surges buck regulators. This operation allows for temperature 5% Accurate Adjustable Heating/Cooling Current control without dead zones or other nonlinearities at Limits low current. This arrangement ensures that the control system does not hunt when the set-point is very close 2% Accurate TEC Voltage Limit to the natural operating point, requiring a small amount No Dead Zone or Hunting at Low Output Current of heating or cooling. An analog control signal precisely sets the TEC current. ITEC Monitors TEC Current Both devices feature accurate, individually-adjustable 1% Accurate Voltage Reference heating current limit and cooling current limit along with maximum TEC voltage limit to improve the reliability of Switching Frequency up to 1MHz optical modules. An analog output signal monitors the Synchronization (MAX8521) TEC current. A unique ripple cancellation scheme helps reduce noise. Ordering Information The MAX8520 is available in a 5mm x 5mm TQFN pack- PART TEMP RANGE PIN-PACKAGE age and its switching frequency is adjustable up to 1MHz through an external resistor. The MAX8521 is MAX8520ETP+ -40C to +85C 20 TQFN- E P * 5mm x 5mm also available in a 5mm x 5mm TQFN as well as MAX8521EBX -40C to +85C 6 x 6 UC S P 3mm x 3mm space-saving 3mm x 3mm UCSP and 36-bump WLP MAX8521ETP+ -40C to +85C 20 TQFN- E P * 5mm x 5mm (3mm x 3mm) packages, with a pin-selectable switch- MAX8521EWX+ -40C to +85C 36 WLP** 3 mm x 3mm ing frequency of 500kHz or 1MHz. +Denotes a lead(Pb)-free/RoHS-compliant package. Applications *EP = Exposed pad. SFF/SFP Modules **Four center bumps depopulated. Fiber Optic Laser Modules Fiber Optic Network Equipment Typical Operating Circuit ATE INPUT Biotech Lab Equipment V DD LX1 3V TO 5.5V PVDD PGND1 FREQ ON CS SHDN OFF TEC CURRENT ITEC MAX8521 MONITOR OUTPUT CURRENT- OS1 CTLI CONTROL I = 1.5A TEC TEC SIGNAL OS2 COMP LX2 REF GND PGND2 Pin Configurations appear at end of data sheet ANALOG /DIGITAL TEMPERATURE CONTROL UCSP is a trademark of Maxim Integrated Products, Inc. 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 AVAILABLESmallest TEC Power Drivers for Optical Modules ABSOLUTE MAXIMUM RATINGS V to GND..............................................................-0.3V to +6V 6 x 6 UCSP (derate 22mW/C above +70C) ...............1.75W DD SHDN, MAXV, MAXIP, MAXIN, 20-Pin 5mm x 5mm x 0.9mm TQFN (derate 20.8mW/C CTLI to GND.........................................................-0.3V to +6V above +70C) (Note 2)...................................................1.67W COMP, FREQ, OS1, OS2, CS, REF, 36-Bump WLP (derate 22mW/C above +70C)............1.75W ITEC to GND...........................................-0.3V to (V + 0.3V) Operating Temperature Range ...........................-40C to +85C DD PVDD1, PVDD2 to GND .............................-0.3V to (V + 0.3V) Maximum Junction Temperature .....................................+150C DD PVDD1, PVDD2 to V ..........................................-0.3V to +0.3V Storage Temperature Range .............................-65C to +150C DD PGND1, PGND2 to GND .......................................-0.3V to +0.3V Lead Temperature (soldering, 10s) .................................+300C COMP, REF, ITEC short to GND....................................Indefinite Soldering Temperature (reflow) LX Current (Note 1) ........................................2.25A LX Current Lead(Pb)-Free (TQFN, WLP)........................................+260C Continuous Power Dissipation (T = +70C) Containing Lead (UCSP)............................................. +240C A 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. Note 1: LX has internal clamp diodes to PGND and PVDD. Applications that forward bias these diodes should take care not to exceed the ICs package power dissipation limits. Note 2: Solders underside metal slug to PCB ground plane. PACKAGE THERMAL CHARACTERISTICS (Note 3) 20 TQFN 36 WLP Junction-to-Ambient Thermal Resistance ( )...............30C/W Junction-to-Ambient Thermal Resistance ( )..................38C/W JA JA )......................2C/W )......................4C/W Junction-to-Case Thermal Resistance ( Junction-to-Case Thermal Resistance ( JC JC 6x6 UCSP Junction-to-Ambient Thermal Resistance ( )................65.5C/W JA Junction-to-Case Thermal Resistance ( ).......................0C/W JC Note 3: 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 (V = V = V = V = 5V, 1MHz mode (Note 4). PGND1 = PGND2 = GND, CTLI = MAXV = MAXIP = MAXIN = REF, SHDN DD PVDD1 PVDD2 T = 0C to +85C, unless otherwise noted. Typical values at T = +25C.) A A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Input Supply Range V 3.0 5.5 V DD Maximum TEC Current 1.5 A Reference Voltage V V = 3V to 5.5V, I = 150A 1.485 1.500 1.515 V REF DD REF Reference Load Regulation V V = 3V to 5V, I = 10A to 1mA 1.2 5.0 mV REF DD REF V = V 140 150 160 MAXI REF V = 5V DD V = V /3 40 50 60 MAXIP/MAXIN Threshold MAXI REF mV Accuracy V = V 143 150 155 MAXI REF V = 3V DD V = V /3 45 50 55 MAXI REF V = 5V, I = 0.2A 0.09 0.14 DD nFET On-Resistance R DS(ON-N) V = 3V, I = 0.2A 0.11 0.16 DD V = 5V, I = 0.2A 0.14 0.23 DD pFET On-Resistance R DS(ON-P) V = 3V, I = 0.2A 0.17 0.30 DD V = V = 5V, T = +25C 0.03 4.00 LX DD A nFET Leakage I A LEAK(N) V = V = 5V T = +85C 0.3 LX DD A V = 0V, T = +25C 0.03 4.00 LX A pFET Leakage I A LEAK(P) V = 0V, T = +85C 0.3 LX A 2 MAX8520/MAX8521