SA638

Philips Semiconductors Preliminary specification IS-54 IF receiver SA638 DESCRIPTION The SA638 is an IF receiver chip which serves the dual mode functionality required by the IS–54 standards for North American cellular telephones. It provides for both the analog FM (AMPS mode) and DQPSK (TDMA digital mode) IF receive functions in a monolithic BiCMOS Integrated Circuit housed in a compact SSOP–24 plastic package. PIN CONFIGURATION RFIN RF BYPASS XTAL OSC (EMITTER) 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 MIXER OUT IF AMP DECOUPLING IF AMP IN IF AMP DECOUPLING IF AMP OUT GND LIMITER IN LIMITER DECOUPLING LIMITER DECOUPLING LIMITER OUT QUADRATURE IN SWITCH OUT APPLICATIONS XTAL OSC (BASE) VCC RSSI FEEDBACK FEATURES RSSI OUT POWER DOWN CONTROL DATA OUT POSTAMP IN POSTAMP OUT SWITCH CONTROL UPDATE for 638 SR00907 Figure 1. Pin Configuration ORDERING INFORMATION DESCRIPTION 24-Pin Plastic TSSOP (Thin Shrink Small Outline Package) TEMPERATURE RANGE -40 to +85°C ORDER CODE SA638 DWG # SOT-355 BLOCK DIAGRAM 24 23 22 21 20 19 18 17 16 15 14 13 IF AMP MIXER GND LIMITER OSCILLATOR FAST RSSI QUAD VCC E B RSSI – + PWR DWN + – + – UPDATE for 638 DATA 1 2 3 4 5 6 7 8 9 10 11 12 SR00908 Figure 2. Block Diagram 1995 Feb 16 1 Philips Semiconductors Preliminary specification IS-54 IF receiver SA638 PIN DESCRIPTIONS Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Mnemonic RFIN(+) RFIN(–) OSCB OSCE ...