LNBH24 Dual LNB supply and control IC with step-up and IC interface Features Complete interface between LNBS and IC bus Built-in DC-DC converter for single 12 V supply operation and high efficiency (typ. 93% 0.5 A) Selectable output current limit through external resistor Compliant with main satellite receivers output voltage specification PowerSSO-36 (ePad) New accurate built-in 22 kHz tone generator meets widely accepted standards (patent pending) Fast oscillator start-up facilitates DiSEqC designed to provide the 13/18 V power supply and encoding the 22 kHz tone signalling for two independent Built-in 22 kHz tone detector supports bi- LNB down-converters in the antenna dishes directional DiSEqC 2.0 and/or multi-switch box. In this application field, it Very low-drop post regulator and high offers a dual tuner STBs with extremely low efficiency step-up PWM with integrated power component count, low power dissipation together N-MOS allow low power losses with simple design and IC standard interfacing. Two output pins suitable for bypassing the output R-L filter and avoiding tone distortion (R- L filter as per DiSEqC 2.0 specs, see typ. application circuits) Overload and over-temperature internal protections with IC diagnostic bits Output voltage and output current level diagnostic feedback by IC bits LNB short circuit dynamic protection +/- 4 kV ESD tolerant on output power pins Description Intended for analog and digital dual satellite receivers/sat-TV, sat-PC cards, the LNBH24 is a monolithic voltage regulator and interface IC, assembled in PowerSSO-36 ePad, specifically Table 1. Device summary Order code Package Packaging LNBH24PPR PowerSSO-36 (Exposed pad) Tape and reel April 2009 Rev 3 1/30 www.st.com 30Contents LNBH24 Contents 1 Block diagram 4 2 Introduction 5 2.1 Application information 5 2.2 DiSEqC data encoding and decoding . 5 2.3 DiSEqC 2.0 implementation 5 2.4 DiSEqC 1.X implementation 5 2.5 Data encoding through external tone generator (EXTM) 6 2.6 IC interface 6 2.7 Output voltage selection . 6 2.8 Diagnostic and protection functions 7 2.9 Output voltage diagnostic 7 2.10 22 kHz tone diagnostic 7 2.11 Minimum output current diagnostic 7 2.12 Output current limit selection . 8 2.13 Over-current and short-circuit protection and diagnostic 8 2.14 Thermal protection and diagnostic . 8 3 Pin configuration . 9 4 Maximum ratings . 11 5 Application circuit 12 6 IC bus interface . 14 6.1 Data validity . 14 6.2 Start and stop condition 14 6.3 Byte format 14 6.4 Acknowledge 14 6.5 Transmission without acknowledge . 14 7 LNBH24 software description 16 7.1 Interface protocol . 16 2/30