SL1925

SL1925 Satellite Zero IF QPSK Tuner IC Preliminary Information DS4955 Issue - 2.0 March 1999 Features q q Ordering Information SL1925/KG/NP2S (Tubes) SL1925/KG/NP2T (Tape and Reel) q q q q q q q Single chip system for direct quadrature down conversion from L-band High signal handling capability for minimum external component count application, requires external RF AGC of 30dB Compatible with DSS and DVB system requirements Excellent gain and phase match up to 30MHz baseband High output referred linearity for low distortion and multi channel application Fully balanced low radiation design Integral RF AGC amplifier Two selectable varactor tuned local oscillators with buffered output for driving external synthesiser loop ESD protection (Normal ESD handling procedures should be observed) Description The SL1925 is a wideband quadrature converter operating from 950 to 2150 MHz, intended primarily for application in satellite tuners. The device contains all elements necessary, with the exception of local oscillator sustaining network, to fabricate a high performance I(n-phase) & Q(uadrature) phase splitter and downconverter optimised for systems containing RF AGC gain control. The device allows for systems containing higher power analog interferers. For most applications RF tunable filtering is not essential. The SL1925 is optimised for use with a low phase noise synthesiser, a range of which are available from Mitel Semiconductor. This will form a complete front end tuner function for digital satellite receiver systems utilising DSP derotation recovery. The device includes a very high signal handling front end with AGC, this provides for gain control, reference local oscillator with output buffer, phase splitter with I and Q mixers and baseband buffer amplifiers with external interstage filtering. Applications q q Satellite receiver systems Data communications systems SL1925 Preliminary Information OPFI Vcc PSout PSoutb Vee Tanks Tanksb Vee Tankv Tankvb Vee NC Vcc OPFQ 14 1 28 Vee IPFI Vee Iout LOsel Vcc RF RFB Vee AGC Qout Vee IPFQ Vee 15 NP28 Figure 1 Pin connections 25 AGC 19 AGC SENDER Iout 27 IPFI 1 OPFI RF RFB 22 21 0 DEG 14 OPFQ 90 DEG 16 IPFQ Tankv Tankvb 9 10 vcov 18 Qout Tanks Tanksb 6 7 vcos DIVIDE BY 2 FREQUENCY AGILE PHASE SPLITTER 3 4 PSout PSoutb Vcc Vee LOsel 24 2, 13, 23 5, 8, 11, 15, 17, 20, 26, 28 Figure 2 Block diagram 2 Preliminary Information Quick Reference Data Characteristic Operating range Input noise figure, DSB, maximum gain, 1500MHz Maximum conversion gain (assuming 6dB filter loss) Minimum conversion gain (assuming 6dB filter loss) IP32T input referred Converter input referred IM3, two tones at 97dBµV IP22T input referred P1dB input referred Baseband amplifier Output limit voltage Gain match up to 22 MHz Phase match up to 22 MHz Gain flatness up to 22 MHz Local oscillator phase noise across entire 950MHz to 2150MHz band: SSB @ 10 kHz offset Table 1 SL1925 950-2150 19 >55