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 (LNB’s) 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. 25 4 FEATURES APPLICATIONS • Dual Channel DiSEqC™ interface • DiSEqC™ controlled LNB’s • Reliable and accurate detectors • Satellite distribution systems • High channel isolation • Mono Block LNB’s • 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 ZLNB254 Document number: Ds32002 Rev. 1 1 of 8 www.diodes.com October 2009 © Diodes Incorporated ZLNB254 DESCRIPTION The ZLNB254 is a dual DiSEqC™ tone detector IC for multiple output LNBs, satellite distribution systems, set-top boxes and DiSEqC™ peripherals. Although intended for use with 22kHz DiSEqC™ signals, the ZLNB254 can be used over the frequency range of 10kHz to 60kHz so it can detect standard 22kHz satellite band control signals as well as regional variations such as those in Japan. The minimum of external components are required to enable this two-channel tone filter and fast envelope detector. The ZLNB254 is particularly suited to low signal level, high distortion DiSEqC™ signal detecting applications. The ZLNB254 includes circuitry necessary to detect the presence of a 22kHz tones modulated on the supply inputs to a LNB or switchbox. The TD outputs are set low on detection of a valid tone or DiSEqC™ signal when applied to the FIN inputs. internally above 60kHz. The remaining detector circuits utilises no other external components. The tone detector can be used to sense either continuous tones or coded tone bursts such as used in DiSEqC™ and similar control systems. To ensure system reliability the tone detector rejects unwanted signals including transients from other parts of the LNB system without the use of any external components. The TD outputs are designed to be compatible with LSTTL and CMOS loads so can drive a microcontroller or other logic directly. To give further protection the resistor which is used to set the filter gain also provides ESD protection. The ZNBL254 provides a small simple solution and is 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 TD2 1 6 TD1 GND 2 5 VCC FIN1 3 4 FIN2 ZLNB254 Document number: Ds32002 Rev. 1 2 of 8 www.diodes.com October 2009 © Diodes Incorporated ZLNB254 Absolute Maximum Ratings Supply Voltage Supply Current Power Dissipation Operating Temperature Range Storage Temperature Range -0.6V to +15V 50mA 350mW -40°C to +85°C -40°C to +125°C Electrical Characteristics Measured at Tamb = 25°C, Vcc = 5V unless otherwise specified. Parameter Conditions Min Supply Voltage Operating Range Supply Current Tone Detectors AC Thresh (1) Switching Delay Limits Typ 3.0 Units 8 V 0.7 2 mA 100 140 100 200 150 mVp/p us Vcc-0.5 0 Vcc-0.2 0.29 Vcc 0.5 V V All outputs unloaded, any combination of valid inputs. Test Circuit 1 TD outputs, Test Circuit 2 Max TD Outputs Voltage High Voltage Low ITD = -2mA, Test Circuit 1, Tone disabled ITD = 5mA, Test Circuit 1, Tone enabled Notes: 1. The tone detector threshold is Vcc dependent. See Application section for details. ZLNB254 Document number: Ds32002 Rev. 1 3 of 8 www.diodes.com October 2009 © Diodes Incorporated ZLNB254 Test Circuit 1 V1 5V ZLNB254 TD2 GND FIN1 1 6 2 5 3 4 TD1 VCC FIN2 100pF R1 C1 62k V2 (See Note 1) Note 1: V2 Characteristics Ty pe:AC source Frequency :- 22kHz Wav ef orm:- Squarewav e, 7.5us tr/tf Test Circuit 2 V1 5V ZLNB254 TD2 GND FIN1 1 6 2 5 3 4 TD1 VCC FIN2 100pF R1 C1 62k V2 (See Note 1) Note 1: V2 Characteristics Ty pe:AC source Frequency :- 22kHz Voltage:300mVp/p Enabled Zero Disabled Tone Input (V2) TD Output Switching Delay s ZLNB254 Document number: Ds32002 Rev. 1 4 of 8 www.diodes.com October 2009 © Diodes Incorporated ZLNB254 Typical Characteristics Icc vs. Vcc vs. Temperature Icc vs. Vcc vs. Input state ZLNB254 Document number: Ds32002 Rev. 1 5 of 8 www.diodes.com October 2009 © Diodes Incorporated ZLNB254 APPLICATIONS INFORMATION Vcc ZLNB254 TD2 GND FIN1 1 6 2 5 3 4 TD1 VCC FIN2 Micro-Controller Vcc R1 C1 100pF 62k C2 R3 100pf 62k LNB Downf eed 2 LNB Downf eed 1 P1 P2 Q1 BC846A P3 P4 Q2 BC846A Gnd R4 100 R2 100 ZLNB254 Application Circuit @ Zetex plc 2009 The above circuit shows the additional components that will be used in a typical ZLNB254 application operating at a Vcc of 5V and detecting 22kHz tones/tone bursts. The transistors Q1 and Q2 are not required for the ZLNB254 operation, they demonstrate how a DiSEqC 2.X (2 way communication) could be achieved. The two detectors of the ZLNB254 are well matched to each other but thresholds of the tone detectors are dependent on Vcc. The table below shows the recommended external input resistor (R1/R3 in above diagram) values needed to meet the guaranteed threshold levels for a range of supply voltages. Recommended Input Resistor Value vs Vcc Table Vcc 3.3V 5V 6V R1 and R3 82K 62K 51K C1 and C2 100pF 100pF 100pF Functional Table FIN 0 kHz 22 kHz TD Out High Low ZLNB254 Document number: Ds32002 Rev. 1 6 of 8 www.diodes.com October 2009 © Diodes Incorporated ZLNB254 PACKAGE OUTLINE – TDFN2020-6 ORDERING INFORMATION DEVICE PACKAGE PART MARK REEL SIZE TAPE WIDTH QUANTITY PER REEL ZLNB254DEETA TDFN2020-6 254 7” 8mm 3000 Units ACKNOWLEDGEMENTS DiSEqC™ is a trademark of Eutlesat ZLNB254 Document number: Ds32002 Rev. 1 7 of 8 www.diodes.com October 2009 © Diodes Incorporated ZLNB254 IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 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