ZLNB254DEETA Diodes Incorporated

225544 A Product Line of Diodes Incorporated ZLNB254 Dual DiSEqC Interface IC SUMMARY The ZLNB254 is a dual channel DiSEqC interface for Satellite Low Noise Blocks (LNBs) and distribution systems. Providing two accurate DiSEqC detectors the ZLNB254 converts the DiSEqC signals into logic level representations enabling reliable and easy detection for a microprocessor. Packaged in a small footprint DFN and only requiring two external components per channel the complete solution is cost effective and requires minimal PCB space. FEATURES APPLICATIONS Dual Channel DiSEqC interface DiSEqC controlled LNBs Reliable and accurate detectors Satellite distribution systems High channel isolation Mono Block LNBs Compatible with Eutelsat and US specifications DiSEqC Actuators Simple and easy to design in. Set-Top Boxes Outputs compatible with LSTTL and CMOS loads Satellite Test Equipment Operates over a wide supply voltage AC satellite control signal detection Temperature compensated 1 of 8 October 2009 ZLNB254 Diodes Incorporated www.diodes.com Document number: Ds32002 Rev. 1 ZLNB254 DESCRIPTION The ZLNB254 is a dual DiSEqC tone detector IC for internally above 60kHz. The remaining detector multiple output LNBs, satellite distribution systems, circuits utilises no other external components. set-top boxes and DiSEqC peripherals. Although intended for use with 22kHz DiSEqC signals, the The tone detector can be used to sense either ZLNB254 can be used over the frequency range of continuous tones or coded tone bursts such as used 10kHz to 60kHz so it can detect standard 22kHz in DiSEqC and similar control systems. To ensure satellite band control signals as well as regional system reliability the tone detector rejects unwanted variations such as those in Japan. signals including transients from other parts of the LNB system without the use of any external The minimum of external components are required to components. enable this two-channel tone filter and fast envelope detector. The ZLNB254 is particularly suited to low The TD outputs are designed to be compatible with signal level, high distortion DiSEqC signal detecting LSTTL and CMOS loads so can drive a applications. microcontroller or other logic directly. The ZLNB254 includes circuitry necessary to detect To give further protection the resistor which is used to the presence of a 22kHz tones modulated on the set the filter gain also provides ESD protection. supply inputs to a LNB or switchbox. The TD outputs are set low on detection of a valid tone or DiSEqC The ZNBL254 provides a small simple solution and is signal when applied to the FIN inputs. packaged in the TDFN2020-6 surface mount package. To enable system flexibility user control is given over the gain and the lower frequency limit of the filter by using a single external resistor and capacitor per channel. The higher frequency limit of the filters is set TDFN2020-6 Top view Pinout Diagram 1 6 TD2 TD1 2 5 GND VCC 3 4 FIN1 FIN2 2 of 8 October 2009 ZLNB254 Diodes Incorporated www.diodes.com Document number: Ds32002 Rev. 1