FM IF RECEIVER FOR FLEX PAGER S1T8515A INTRODUCTION 24−SSOP−BD209 The S1T8515A is a designed for FM detection on the FLEX pager set. It consists of an Oscillator, Mixer, Limiting IF Amp. Quadrature Detector, Regulator, RSSI (Received Signal Strength Indicator), Bit Rate Filter, and a 2-level / 4-level FSK comparator. It has a 24-SSOP (0.65mm)Surface Mount Package. FEATURES • Internal A/D converter for 4 level FSK (2-bit ADC) • High transmission rate: 6400bps (Max.) • Operating voltage range: VCC1 = 1.1 ~ 4.0V • Typical supply current: 1.5mA at 1.4V • Low battery detection circuit (alarm function): 1.05V • Mixer operating frequency: 10 ~ 50MHz • Package type: 24-SSOP (0.65mm) ORDERING INFORMATION Device Package Operating Temperature S1T8515A01-U0B0 24−SSOP−BD209 −20°C ~ +70°C 1 S1T8515A FM IF RECEIVER FOR FLEX PAGER BLOCK DIAGRAM MI GND 24 23 2nd MIX REGO REGC 22 21 1.0V Regulator 1 FSKO1 FSKO2 20 Alarm 19 18 2 OSCO BSC QC1 17 16 FSK Comparator Limiting IF Amplifier X-tal Osc. OSCI AO 15 14 RSSI 13 Quick Charge Quad Detector Bit-rate Filter 3 4 5 6 7 8 9 10 11 12 MO Vcc LI LD FSKR1 QD C1 C2 C3 FIL VAR PIN CONFIGURATION OSCI 1 24 MI OSCO 2 23 GND MO 3 22 REGO Vcc 4 21 REGC LI 5 20 AO LD 6 FSKR1 7 18 FSKO2 QD 8 17 BSC C1 9 16 QC1 C2 10 15 QC2 C3 11 14 FSKR2 FIL VAR 12 2 QC2 FSKR2 S1T8515A 19 FSKO1 13 RSSI FM IF RECEIVER FOR FLEX PAGER S1T8515A PIN DESCRIPTION Pin No Symbol Description 1 OSCI Oscillator input (Base). The oscillator is an internally biased colpitts type. 2 OSCO Oscillator output (Emitter). 3 MO Mixer output (Output impedance ≈ 1.5kΩ) Connect a 455kHz filter between this pin and the LI. 4 VCC Power supply voltage. 5 LI IF limiter amplifier input (Input impedance ≈ 1.5kΩ). 6 LD Bypass capacitor connect pin for the IF limiter amp. 7 FSKR1 Differential Amp Reference input on the FSK comparator. 8 QD Quadrature detection, phase shiftier input. 9 10 11 C1 C2 C3 Capacitors for bit-rate filter. 12 FIL VAR Bit-rate filter selection. High: Internal cut-off frequency will be set to Low. Low: Internal cut- off frequency will be set to High. 13 RSSI RSSI output. The power of received RF signal can be detected by monitoring the limiter amplifier. 14 FSKR2 Differential Amp Reference input on the FSK comparator for 4-Level FSK Detection. 15, 16 QC2, QC1 Quick charge control 2 & 1. High: Quick charge-discharge on. Low: Quick charge-discharge off. 17 BSC Battery saving control. High: Battery saving off-normal mode operation. Low: Battery saving on-battery save mode operation. 18 FSKO2 The output signal from the Bit-rate filter is compared with FSK Reference signal, and the final output signal will be output to the LSB after 4-Level FSK detection. 19 FSKO1 The final output signal will be output to the MSB after 4-Level FSK detection. 20 AO Alarm output. This pin becomes high, when VCC drops below 1.05V. 21 REGC S1T8515A has an internal PNP transistor. But, it also can support an external PNP transistor to control the power. 22 REGO Regulated voltage output. 23 GND Ground. 24 MI Mixer input (Input impedance ≈ 1.5kΩ). 3 S1T8515A FM IF RECEIVER FOR FLEX PAGER ABSOLUTE MAXIMUM RATINGS Characteristic Symbol Value Unit 4 V 760 mW Supply Voltage VCC (MAX) Power Dissipation PD Operating Temperature TOPR −20 — +70 °C Storage Temperature TSTG −55 — +125 °C ELECTRICAL CHARACTERISTICS (VCC = 1.4V ±5%, fIN (2MIX) = 21.4MHz, fDEV = ±4.8kHz, fMOD = 800Hz, Ta = 25°C, FIL_VAR = “H”, unless otherwise specified) Characteristic Symbol Test Conditions Min. Typ. Max. Unit ICCN No Input Signal − 1.5 1.75 mA ICCS Battery Saving − 0 10 µA Alarm detection voltage VAD − 1.0 1.05 1.1 V Alarm low level output voltage VO (AL) − − 0.4 V − − 2 µA − − 0.4 V Operating current I = 100µA − Alarm high level leakage current ILKG (AL) FSK low level output voltage VL (FSK) FSK high level leakage current ILKG (FSK) − − − 2 µA Regulator output voltage VOREG − 0.95 1.0 1.05 V Quick charge current IC − 50 70 − µA Input for −3dB sensitivity VLIM Mixer Input − 2.5 7.5 µVrms Recovered audio output voltage VO (RAO) VIN (2MIX) = 500µVrms 36 54 78 mVrms Mixer conversion gain ∆GV (M) Ceramic Filter loss = −1dB 8 12 16 dB Signal to noise ratio S/N VIN (MIX1N) = 500µVrms 38 55 − dB Total Harmonic Distortion THD VIN (MIX1N) = 500µVrms − 2.0 3.5 % Mixer 3rd order intercept point 3RD − − −10 − dBm Mixer input resistance RI (MIX) − 3.5 5 6.5 kΩ Limiting amp input resistance RI (LA) − 0.9 1.5 2.1 kΩ AM rejection ratio AMR VIN (2MIX) = 500µVrms (AM = 300%) 25 40 − dB Data shaping output duty DR VIN (2MIX) = 500µVrms 40 50 60 % RSSI output voltage VRSSI VIN (2MIX) = 1mVrms 0.49 0.7 0.91 V RSSI output resistance RRSSI 90 100 110 kΩ 4 I = 100µA − FM IF RECEIVER FOR FLEX PAGER S1T8515A TEST CIRCUIT RF Input Alarm out FSKO1 Reg. out 2.2µ + 51 100K 100K FSKO2 Vcc 24 GND REGO REGC 22 2nd MIX 21 1.0V Regulator 1 FSKO1 20 FSKO2 19 18 2 OSCO 3 MO 4 Vcc 5 LI 20.945MHz BSC 17 QC1 16 6 7 LD FSKR1 0.1µ CFMW455E QC2 FSKR2 15 14 RSSI 13 Bit-rate Filter 8 QD 9 C1 + 10µ 0.1µ Quick Charge Quad Detector 56p 39p RSSI 10µ L FSK Comparator Alarm Limiting IF Amplifier X-tal Osc. OSCI AO FSKR2 + L H 23 QC2 100K 1000p MI QC1 10 C2 1000p CDBM 455 11 C3 1200p 12 FIL VAR 1500p H L 3.3K + 10u 5 S1T8515A FM IF RECEIVER FOR FLEX PAGER NOTES 6