NJM2294

NJM2294 FM IF IC FOR PAGER ■ GENERAL DESCRIPTION NJM2294 is a super low current FM IF IC for pagers. It includes almost all functions of the paging IF system. In those functions, the RSSI function can be used for automatic gain control. When the electric field strength is high, the RSSI output signal can control the attenuation of an RF amplifier to improve the received condition. ■ PACKAGE OUTLINE NJM2294V ■ FEATURES ● Low Operating Voltage (V+=1.1 to 4.0V) ● Super low Operating Current (600µA, V+=1.4V) ● RSSI (Received Signal Strength Indicator) ● FSK wave shaper ● Battery check alarm function (Alarm Voltage=1.1V typ.) ● Battery saving function ● A high output current voltage regurator with an external transistor (Vreg=1.0V typ.) ● A ceramic discriminator is available. ● Package Outline SSOP16 ● Bipolar Technology ■ RECOMMENDED OPERATIONAL CONDITION ● Operating Voltage V+ 1.1 to 4.0V ■ PIN CONFIGURATION NJM2294V Ver.2003-12-09 -1- NJM2294 ■ ABSOLUTE MAXIMUM RATINGS PARAMETER Supply Voltage Power Dissipation Operating Temperature Range Storage Temperature Range SYMBOL V+ PD Topr Tstg RATINGS 5 300 -20 to +75 -40 to +125 (Ta=25°C) UNIT V mW °C °C ■ ELECTRICAL CHARACTERISTICS PARAMETER No signal Operating Current Battery saving Operating Current IF amplifier input resistance S/N1 S/N2 -3dB limitting sensitivity Demodulated output level AM rejection ratio Duty ratio of wave shaped output RSSI output voltage RSSI output resistance Quick charge / discharge current Alarm voltage Regulator output voltage Low level output voltage of VALM terminal High level leak current of VALM terminal Low level output voltage of FSK-OUT terminal High level leak current of FSK-OUT terminal Low level output voltage of REG-CONT terminal SYMBOL ICCq ICCs RIN S/N1 S/N2 VIN (lim) VOD AMR DR VRSSI RRSSI Ich Valm Vreg ValmL IalmH VfskL IfskH VregL TEST CIRCUIT 11 12 1 1 1 1 1 2 10 13 3 8 4 5 6 7 9 (V+=14V, fi=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) TEST CONDITION VI=0, 10pin=V + MIN. - TYP. 600 0 2 62 35 22 46 50 50 0.62 62 65 1.10 1.00 0.1 0 0.1 0 - MAX. 900 5 27 65 60 0.76 110 1.15 1.05 0.4 2 0.4 2 0.6 UNIT µA µA kΩ dB dB dBµEMF mVrms dB % V kΩ µA V V V µA V µA V VI=0, 10pin=GND VI=60dBµEMF VI=25dBµEMF - VI=60dBµEMF VI=60dBµEMF, AM=30% VI=60dBµEMF VI=80dBµEMF 30 40 0.48 - 4pin=GND, 8pin=0.18V 35 1.05 RL=430Ω IL=100µA 0.95 - IL=100µA - IL=100µA - -2- Ver.2003-12-09 NJM2294 ■ TEST CIRCUIT Test Cricuit 1 S/N1, S/N2, VIN (lim), VOD , AMR Test Circuit 2 Ver.2003-12-09 -3- NJM2294 Test Cricuit 3 Test Circuit 4 Test Cricuit 5 IalmH Test Circuit 6 Test Cricuit 7 IfskH Test Circuit 8 -4- Ver.2003-12-09 NJM2294 Test Circuit 9 Test Circuit 10 VRSSI Test Circuit 11 Test Circuit 12 Test Circuit 13 Ver.2003-12-09 -5- NJM2294 ■ TERMINAL FUNCTION PIN NO. 1 SYMBOL IF-IN FUNCTION An IF amplifier input. Typical input impedance is 2kΩ. EQUIVALENT CIRCUIT 3 DEC A Decoupling terminal which is connected with a decoupling capacitor. 2 GND Ground 5 QUAD-IN An input terminal of a quadrature detection circuit. This terminal will be connect with a ceramic discriminator. 9 RSSI OUT An RSSI Output. This voltage level is in logarithmic proportion to the input signal level. 6 AF-OUT An FM output. demodulated signal -6- Ver.2003-12-09 NJM2294 ■ TERMINAL FUNCTION PIN NO. 7 SYMBOL LPF-IN FUNCTION An input terminal of a low pass filter. This terminal is biased from the AF-OUT terminal (6pin) through an external RC filter. EQUIVALENT CIRCUIT 8 LPF-OUT An output terminal of a low pass filter. 4 FSK-REF A Reference input terminal of a wave shaping comparator. This terminal is connected with an external capacitor. 12 FSK-OUT An output terminal of a wave shaping circuit. The Wave shaped signal inverted for the LPF output comes out. 10 BS A Control terminal of a battery saving circuit. H : This circuit is OFF. L : This circuit is ON. Ver.2003-12-09 -7- NJM2294 ■ TERMINAL FUNCTION PIN NO. 11 SYMBOL CHARGE FUNCTION A Control terminal of a quick charge / discharge circuit. H : This circuit is ON. L : This circuit is OFF. EQUIVALENT CIRCUIT 13 VALM An output terminal of the alarm signal. + When V drops down to 1.1V, this output becomes high. 14 REG CONT A Control terminal of an external PNP transistor used for the regulator. 15 REG-OUT A Monitering terminal of the regulator. 16 V + Supply voltage -8- Ver.2003-12-09 NJM2294 ■ FSK WAVE SHAPING FUNCTION When the demodulated FSK signal is weak or noisy, the micro computer may fail to read data. The wave shaping circuit (comparator) will change those signals to the correct logical signal to prevent the readerror. ■ QUICK CHARGE / DISCHARGE FUNCTION The DC voltage of the FSK-REF terminal is equal to that of the demodulated FSK signal. When the battery saving state turns into the ordinary state, the FSK-REF terminal voltage will be late to come up to the reference voltage by the time constant of an external capacitor and an internal resistor, and the wave shaped data may be failed. This circuit will charge/ discharge the external capacitor quickly to prevent the error. When the DC level of the FM demodulated output changes in the operation mode of this function, the FSK-REF terminal voltage follows to the FSK demodulated output DC voltage, and the FSK output duty ratio can be constant. ■ APPLICATION CIRCUIT [CAUTION] The specifications on this databook are only given for information , without any guarantee as regards either mistakes or omissions. The application circuits in this databook are described only to show representative usages of the product and not intended for the guarantee or permission of any right including the industrial rights. Ver.2003-12-09 -9-