LNBK20D2 LNB SUPPLY AND CONTROL VOLTAGE REGULATOR (PARALLEL INTERFACE) COMPLETE INTERFACE FOR TWO LNBs REMOTE SUPPLY AND CONTROL GUARANTEED 400mA OUTPUT CURRENT LNB SELECTION AND STAND-BY FUNCTION BUILT-IN TONE OSCILLATOR FACTORY TRIMMED AT 22KHz FAST OSCILLATOR START-UP FACILITATES DiSEqC ENCODING SO-20 TWO SUPPLY INPUTS FOR LOWEST DISSIPATION BYPASS FUNCTION FOR SLAVE OPERATION LNB SHORT CIRCUIT PROTECTION AND (MI) and the LNBA pin, thus leaving all LNB DIAGNOSTIC powering and control functions to the Master Receiver. This electronic switch is closed when AUXILIARY MODULATION INPUT EXTENDS the device is powered and EN pin is LOW. FLEXIBILITY The regulator outputs can be logic controlled to be CABLE LENGTH COMPENSATION 13 or 18 V (typ.) by mean of the VSEL pin for INTERNAL OVER TEMPERATURE remote controlling of LNBs. Additionally, it is PROTECTION possible to increment by 1V (typ.) the selected BACKWARD CURRENT PROTECTION voltage value to compensate the excess voltage COST-EFFECTIVE VERSION OF LNBP drop along the coaxial cable (LLC pin HIGH). SERIES In order to reduce the power dissipation of the device when the lowest output voltage is selected, DESCRIPTION the regulator has two Supply Input pins V and CC1 Intended for analog and digital satellite receivers, V . They must be powered respectively at 16V CC2 the LNBK20D2 is a monolithic linear voltage (min) and 23V (min), and an internal switch regulator, assembled in SO-20, specifically automatically will select the suitable supply pin designed to provide the powering voltages and the according to the selected output voltage. If interfacing signals to the LNB downconverter adequate heatsink is provided and higher power situated in the antenna via the coaxial cable. It has losses are acceptable, both supply pins can be the same functionality of the LNBP1X and powered by the same 23V source without LNBP20 series, at a reduced output current affecting any other circuit performance. capability. Since most satellite receivers have two The ENT (Tone Enable) pin activates the internal antenna ports, the output voltage of the regulator oscillator so that the DC output is modulated by a is available at one of two logic-selectable output 0.3 V, 22KHz (typ.) square wave. This internal pins (LNBA, LNBB). When the IC is powered and oscillator is factory trimmed within a tolerance of put in Stand-by (EN pin LOW), both regulator 2KHz, thus no further adjustments neither outputs are disabled to allow the antenna external components are required. downconverters to be supplied/controlled by A burst coding of the 22KHz tone can be others satellite receivers sharing the same coaxial accomplished thanks to the fast response of the lines. In this occurrence the device will limit at 3 ENT input and the prompt oscillator start-up. This mA (max) the backward current that could flow helps designers who want to implement the from LNBA and LNBB output pins to GND. DiSEqC protocols (*). For slave operation in single dish, dual receiver In order to improve design flexibility and to allow systems, the bypass function is implemented by implementation of newcoming LNB remote control an electronic switch between the Master Input pin standards, an analogic modulation input pin is July 2003 1/14 Obsolete Product(s) - Obsolete Product(s)LNBK20D2 available (EXTM). An appropriate DC blocking IMPEDANCE. If the overload is still present, the capacitor must be used to couple the modulating protection circuit will cycle again through t and off signal source to the EXTM pin. When external ton until the overload is removed. Typical t +t on off modulation is not used, the relevant pin can be left value is 1200ms when a 4.7F external capacitor open. is used. Two pins are dedicated to the overcurrent This dynamic operation can greatly reduce the protection/monitoring: CEXT and OLF. The power dissipation in short circuit condition, still overcurrent protection circuit works dynamically: ensuring excellent power-on start up even with as soon as an overload is detected in either LNB highly capacitive loads on LNB outputs. output, the output is shut-down for a time Toff The device is packaged in Multiwatt15 for determined by the capacitor connected between thru-holes mounting and in PowerSO-20 for CEXT and GND. Simultaneously the OLF pin, that surface mounting. When a limited functionality in a is an open collector diagnostic output flag, from smaller package matches design needs, a range HIGH IMPEDANCE state goes LOW. of cost-effective PowerSO-10 solutions is also After the time has elapsed, the output is resumed offered. All versions have built-in thermal for a time t =1/15t (typ.) and OLF goes in HIGH protection against overheating damage. on off (*): External components are needed to comply to level 2.x and above (bidirectiona) DiSEqC bus hardware requirements. DiSEqC is a trademark or EUTELSAT. PIN CONFIGURATION (top view) 2/14 Obsolete Product(s) - Obsolete Product(s)