A8285SLBTR-T Allegro

A8285 and A8287 LNB Supply and Control Voltage Regulator Description Features and Benefits Intended for analog and digital satellite receivers, the LNB LNB selection and standby function (low noise block) converter regulator is a monolithic linear and Provides up to 500 mA load current 2 switching voltage regulator, specifically designed to provide Two-wire serial I C interface power and interface signals to an LNB downconverter, via Built-in tone oscillator, factory-trimmed to 22 kHz coaxial cable. facilitates DiSEqC 2.0 encoding Auxiliary modulation input The device uses a 2-wire bidirectional serial interface, 22 kHz tone detector facilitates DiSEqC decoding 2 compatible with the I C (Inter-C bus) standard, that operates (A8287 only) up to 400 kHz. Tracking switch-mode power converter for lowest dissipation The A8285 is supplied in a 16-lead plastic power SOIC with LNB overcurrent protection and diagnostics internally fused leads for thermal dissipation. The A8287 is Internal overtemperature protection supplied in a 24-lead plastic power SOIC with internally fused LNB voltages (16 possible levels) compatible with all leads. Both devices are also available in lead (Pb) free versions, common standards with 100% matte tine leadframe plating. Packages 16-pin SOIC 24-pin SOIC (A8285) (A8287) Functional Block Diagram L1 D1 V C10 C1 C5 C2 C4 IN 100 nF 33 F 33 H 100 nF 100 nF 100 F VIN LX VCP BOOST VREG Internal BOOST C3 Regulator 220 nF Feedback Charge Pump OSC In VPUMP Boost Converter Overcurrent OSC DISABLE R1 15 EXTM 100 mV L2 33 H LNB 22 kHz R3 R4 R5 Clock 1.5 F Tone Divider C7 V Generator DD Tracking D2 220 nF Regulator C6 SDA TCAP Output SCL 6.8 nF Voltage C8 GM Select ADD 220 R2 TOUT 10 nF C9 TDI Fault Monitor Overcurrent IRQ Overcurrent 22 kHz Tone V R6 DD TSD Detector TDO Undervoltage A8285-DS, Rev. FA8285 and LNB Supply and Control Voltage Regulator A8287 Selection Guide Part Number Pb-free Package Description A8285SLB 16-pin SOIC Tone detect not provided A8285SLB-T Yes 16-pin SOIC Tone detect not provided A8287SLB 24-pin SOIC All features A8287SLB-T Yes 24-pin SOIC All features Absolute Maximum Ratings Characteristic Symbol Notes Rating Unit Load Supply Voltage V 16 V IN Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Output Current I Under any set of conditions, do not exceed the Internally Limited OUT specified current rating or a junction tempera- ture of +150C LNB, BOOST 0.3 to 28 V Output Voltage TOUT 0.3 to 22 V EXTM 0.3 to 5 V Logic Input Other 0.3 to 7 V Logic Output 0.3 to 7 V See power dis sipation information in the Application Package Power DIssipation Information section Operating Temperature Ambient T 20 to 85 C A Junction T 20 to 150 C J Storage T 55 to 150 C S Allegro MicroSystems, LLC 2 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000 www.allegromicro.com