NJM2590V

NJM2590/97 455kHz INPUT FM IF DEMODULATOR GENERAL DESCRIPTION The NJM2590 and NJM2597 are low current FM IF demodulator ICs with 455kHz IF input, which operate from 1.6V supply. The NJM2590/97 contain the minimum functions required to FM IF demodulator, that is, IF amplifier, quadrature detector, LPF amplifier, FSK comparator, RSSI, and RSSI comparator. It offers unmatched design flexibility. NJM2590V/97V PACKAGE OUTLINE FEATURES Low Operating Voltage 1.6V to 5.5V Low Operating Current 550uA at V+ =1.8V IF Input Frequency 455kHz (standard) RSSI Comparator The Range of Linear Area on RSSI Output versus IF Input Characteristics NJN2590 IF Input level=25 to 60 dBuVEMF (reference value) NJM2597 IF Input level=35 to 85 dBuVEMF (reference value) Bipolar Technology Package Outline SSOP14 BLOCK DIAGRAM V + CARRIER SENSE RSSI SENSE LEVEL OUT 13 12 11 FSK CHARGE OUT 10 9 LPF OUT 8 14 RSSI COMP R SSI IF AMP FSK COMP CHARGE QUAD DET LPF 1 IF IN 2 GND 3 DEC 4 FSK REF 5 QUAD IN 6 AF OUT 7 LPF IN Ver.2004-08-25 -1- NJM2590/97 ABSOLUTE MAXIMUM RATINGS PARAMETER Supply Voltage Power Dissipation Operating Temperature Storage Temperature SYMBOL V+ PD Topr Tstg RATINGS 8.0 300 - 40 to +85 - 40 to +125 (Ta=25°C) UNIT V mW °C °C RECOMMENDED OPERATIONAL CONDITION PARAMETER Supply Voltage SYMBOL V+ TEST CONDITIONS MIN. 1.6 TYP. 1.8 MAX. 5.5 (Ta=25°C) UNIT V ELECTRICAL CHARACTERISTICS (Ta=25°C, V+=1.8V, fin=455kHz, fmod=600Hz, fdev=±4kHz) PARAMETER Current Consumption IF Amplifier Input Resistance Signal to Noise Ratio 1 Signal to Noise Ratio 2 - 3dB Limiting Sensitivity Demodulated Output Level AM Rejection Raito Duty Ratio of Wave Shaped Output Quick Charge/Discharge Current NJM2590 RSSI Output Voltage NJM2597 High Level Leak Current of IfskH FSK OUT Terminal Low Level Voltage of VfskL FSK OUT Terminal High Level Leak Current of IcryH CARRIER SENSE Terminal Low Level Voltage of Vcr yL CARRIER SENSE Terminal Bias Current of I level SENSE LEVEL Terminal The value shown in parenthesis are reference values. Vrssi Vi=80dBu EMF V FSK OUT=V+ I FSK OUT =100uA V CARRIAR SENSE =V+ I CARRIER SENSE=100uA V CARRIER SENSE =0.8V 0.8 (-0.1) (-0.1) 0.0 (-1.0) 1.1 (0) 0.1 (0) 0.1 (0) 1.4 (0.1) 0.4 (0.1) 0.4 (1.0) uA V uA V uA SYMBOL Iccq Rin S/N1 S/N2 Vin(lim) V od AMR DR I ch Vi=60dBu EMF Vi=60dBu EMF AM=30% Vi=60dBu EMF V FSK OUT=GND V LPF OUT = 0.18V Vi=40dBu EMF Vi=60dBu EMF Vi=25dBu EMF TEST CONDITIONS No Signal MIN. 440 (1.6) 35 40 35 0.7 TYP. 550 2 60 30 22 40 50 50 65 0.9 MAX. 660 (2.4) 27 65 60 110 1.1 V UNIT uA kΩ dB dB dBu EMF mVrms dB % uA -2- Ver.2004-08-25 NJM2590/97 TEST CIRCUIT This test circuit allows the measurement of all parameters described in “ELECTRICAL CHARACTERISTICS”. This test circuit includes some electrical switches that should be in the suitable positions for the measurement of each parameter. For the best measurement of each parameter, the drawings of ”Test Circuit 1 to 10” are additionally prepared to show the switching positions and other changes of connection. Note that “Test Circuit 1 to 10” are not the complete circuit to measure. CARRIER SENSE V+ 10u 100k RSSI FSK OUT OUT A 100k SENSE LEVEL 1000p 10 9 8 0.01u 14 13 12 11 RSSI COMP FSK COMP RSSI IF AMP CHARGE QUAD DET LPF 1 2 3 4 5 6 7 0.1u 0.1u 51 A CD 10u 10u V+ 3.0k 68k 68k 3300p 68k 560p 0.18V Note : 1. “CD” means a ceramic discriminator of 455kHz ; CDBCB455KCAY66-R0(MURATA,JAPAN) Ver.2004-08-25 -3- NJM2590/97 Test Circuit 1 S/N1, S/N2, Vin(lim), Vod, AMR Test Circuit 2 DR 0.1u 1 51 8 S/N1, S/N2, Vin(lim), Vod, AMR 0.1u 1 51 10 100k DR V+ Test Circuit 3 Iccq Test Circuit 4 Vrssi 0.1u 2 14 A V+ Iccq 1 51 0.1u 4 11 Vrssi 1000p Test Circuit 5 Ich Test Circuit 6 VfskL 100uA 4 Ich 14 10u 9 V+ 10 V VfskL V+ A 7 8 0.18V -4- Ver.2004-08-25 NJM2590/97 Test Circuit 7 IfskH Test Circuit 8 IcryH 10 100k V 13 100k V V+ IfskH = V/100k V+ IcryH = V/100k Test Circuit 9 VcryL Test Circuit 10 Ilevel 100uA 13 V VcryL SENSE LEVEL 0.8V V+ 12 A Ilevel Ver.2004-08-25 -5- NJM2590/97 EVALUATION BOARD For obtaining actual performance data, an evaluation board is available. Note that this board is not prepared for the reference design of parts layout, pattern layout and so on. Circuit Diagram V+ 10u 100k 1000p 14 13 12 11 10 9 8 CARRIER SENSE RSSI FSK SENSE LEVEL OUT OUT LPF OUT 100k SW 0.01u RSSI COMP GND FSK COMP RSSI IF AMP CHARGE QUAD LPF 1 2 3 4 5 6 7 0.1u 0.1 CD 10u 10u V+ 3.0k 68k 68k 3300p 68k 560p IF IN FSK REF CD: Ceramic discriminator, CDBCB455KCAY66-R0 (Murata manufacturing Co., Ltd.) Circuit Board V+ CARRIER SENSE GND IF IN SENSE LEVEL RSSI OUT FSK OUT FSK REF LPF OUT GND -6- Ver.2004-08-25 NJM2590/97 TERMINAL FUNCTION (Ta=25°C, V+=1.8V) Pin No. SYMBOL EQUIVARENT CIRCUIT VOLTAGE FUNCTION IF Amplifier Input. Typical input impedance is 2kΩ. Built in ESD protective circuit. IF Decoupling. Connected with an external decoupling capacitor. Built-in ESD protective circuit Ground. 2 GND -- V+ 1 IF IN 1 3 1.75V 3 DEC 1.75V V+ 4 FSK REF 4 0.9V FSK Reference Input. This is a reference input of wave shaping comparator. Connected with an external capacitor. A quick charge/discharge circuit offers the voltage of pin 4 comes the same voltage of pin 8 quickly. Built-in ESD protective circuit. Quadrature Detector Input. Connected with a ceramic discriminator. Built-in ESD protective circuit. V+ 5 5 QUAD IN 0.5V V+ FM demodulated signal output. Built-in ESD protective circuit. 0.2V 6 AF OUT 6 Ver.2004-08-25 -7- NJM2590/97 Pin No. SYMBOL EQUIVARENT CIRCUIT VOLTAGE FUNCTION Low Pass Filter Input. This terminal is biased from the pin 6 through an external RC filter. Built-in ESD protective circuit. V+ 7 LPF IN 7 8 0.18V 8 LPF OUT 0.18V Low Pass Filter Output. Built-in ESD protective circuit. V+ 9 CHARGE 9 - Quick Charge/Discharge Control. The power supply output voltage to pin 9 sets up the quick charge / discharge circuit. Instead of the power supply, another power source can also be used within the limit of the rated supply voltage. Built-in ESD protective circuit between pin 9 and ground. FSK Output. FSK comparator is a wave shaping circuit. A LPF output signal is inverted and wave-shaped. Instead of the power supply, another power source can also be used within the limit of the rated supply voltage. Built-in ESD protective circuit between pin 10 and ground. V+ 10 FSK OUT 10 - V+ 11 RSSI OUT 11 50mV Received Signal Strength Indicator Output. Pin 11 outputs DC level proportional to the log of input signal level to pin 1. Built-in ESD protective circuit. -8- Ver.2004-08-25 NJM2590/97 Pin No. SYMBOL EQUIVARENT CIRCUIT VOLTAGE FUNCTION Sense Level Input. Built-in ESD protective circuit. V+ 12 SENSE LEVEL 12 - V+ 13 CARRIER SENSE 13 - Carrier Sense Output. The result of RSSI comparator is output by comparing RSSI output level with an external input level to pin 12. Built-in ESD protective circuit between pin 13 and ground. Power Supply. 14 14 V+ - Ver.2004-08-25 -9- NJM2590/97 DESCRIPTION 1. FSK comparator (FSK COMP) FSK comparator is a wave shaping circuit. When the demodulated FSK signal is weak or noisy, the computer may fail to read this signal. To prevent the read-error, the wave shaping circuit will change this weak or noisy signal to the correct signal. Pin 10 usually pulls up to power supply output voltage through an external high-valued resistor. This external resistor can be connected to another power source within the limit of absolute maximum ratings. 300kΩ 300kΩ + V+ 100kΩ 8 4 10uF 10 2. Quick charge/ discharge circuit The DC voltage of pin 4 is ordinarily equal to that of the demodulated FSK signal. When the initial state of power-up turns into a steady state, the voltage of pin 4 will be late to come up to the reference voltage by reason of time constant of an external capacitor and an internal resistor. At that time the wave shaped data may be failed to read correctly. The quick charge/discharge circuit serves a useful function to shorten the rise time when power is turned on. When power supply is hooked up to pin9 upon turning the power on, this circuit will charge/discharge the external capacitor quickly to prevent read-error. Instead of the power supply, another power source can also be used within the limit of the rated supply voltage. During the high-speed charge/discharge circuit runs, DC level of FM demodulated signal may varies with frequency shift or others. Even in such a case, the voltage of pin 4 follows the voltage of FM demodulated signal so that the duty ratio of wave shaped output can keep constant. 2.7kΩ 80kΩ 300kΩ 80kΩ + - 300Ω 2kΩ V+ 9 4 - 10 - Ver.2004-08-25 NJM2590/97 3. Carrier sense The result of comparator is output to pin13 by comparing the output voltage of pin11 with external reference voltage of pin 12. Because pin13 is an open-collector terminal, an external resistor can be connected to another power supply within the limit of absolute maximum ratings. - + 11 1000pF 12 SENSE LEVEL 13 V+ 100kΩ 4. RSSI circuit (RSSI) A DC voltage corresponding to the input level of pin1 is output to pin11. The internal resistance of pin11 is around 48 kΩ. The RSSI characteristics can be changed by adding an external resistor,. In such a case, note that the temperature characteristics of pin 11 may alter due to a disparity between the temperature coefficient of the external resistor and the internal resistor of pin 11. V+ 500Ω 300Ω 48kΩ 11 1000pF Rext 5. Low pass filter (LPF) This is a 3rd-order multiple feedback filter. The cut-off frequency Fc is obtained by ; Fc = 1 [ Hz ] 2π RaRbRcCaCb Cc 3 where Ra=Rb=Rc or Ca=Cb=Cc Each of pin7(LPF IN) and pin8(LPF OUT) has a built-in ESD protective resistor 300Ω. 300Ω + - 300Ω 6 Ra 68kΩ Rb 68kΩ Ca 3300pF Rc 68kΩ Cc 0.01uF 7 8 Cb 560pF Ver.2004-08-25 - 11 - NJM2590/97 APPLICATION CIRCUIT CARRIER SENSE V+ 10u 100k 1000p 14 13 12 11 10 9 8 RSSI FSK OUT OUT 100k 0.01u RSSI COMP FSK COMP RSSI IF AMP CHARGE QUAD LPF 1 2 3 4 5 6 7 CD 0.1 0.1u 10u 10u IF IN V+ 3.0k 68k 68k 3300p 68k 560p The NJM2590 itself works with the operational temperature from - 40 to +85°C. However this matter is not meant to insure the reliability of this application circuit under the temperature from - 40 to +85°C. CERAMIC DISCRIMINATOR (especially designed for NJM2590/97) To optimize some important performance, the following ceramic discriminator is available. For more information on this CD and 450kHz CD, please contact the CD supplier. CDBCB455KCAY66-R0 (Murata Manufacturing Co., Ltd., JAPAN) - 12 - Ver.2004-08-25 NJM2590/97 TYPICAL CHARACTERISTICS S+N,AM R versus Supply Voltage 70 60 S+R, AMR (dB) Operating Current versus Supply Voltage (No signal,Ta=25°C) 800 (Vi=60dBuEMF, fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) S+N AMR Operating Current Iccq (mA) 700 600 500 400 300 200 100 0 0 1 2 3 Supply Voltage V+ (V) 4 5 6 50 40 30 20 10 0 0 1 2 3 Supply Voltage V+ (V) 4 5 6 Demodulated Output versus Supply Voltage Demodulated Output Vod (mVrms) RSSI Output Voltage versus Supply Volgate 1.8 (Vi=40dBuEMF, fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) 80 70 60 50 40 30 20 10 0 0 (Vi=60dBuEMF, fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) RSSI Output Voltage Vrssi (V) 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 1 2 3 Supply Voltage V+ (V) 4 5 6 1 2 3 Supply Voltage V+ (V) 4 5 6 -3dB Limiting Sensitivity versus Supply Voltage (fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) 30 25 20 15 10 5 0 0 1 2 3 Supply Voltage V+ (V) 4 5 6 Duty Ratio of Wave Shaped Output versus Supply Voltage (Vi=60dBuEMF, fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) 60 58 56 -3dB Limiting Sensitivity Vin(lim) (dBuEMF) Duty Ratio DR (%) 54 52 50 48 46 44 42 40 0 1 2 3 Supply Voltage V+ (V) 4 5 6 Quick Charge OFF Quick Charge ON Ver.2004-08-25 - 13 - NJM2590/97 S+N, AMR versus IF Input Level 10 0 -10 S+N, AMR (dB) S-Curve Characteristics S+N (Vi=60dBuEMF, fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) 350 (Vi=60dBuEMF, fmod=600Hz, fdev=±4kHz,Ta=25°C) 60dBuVEMF AF Output Voltage (mV) 300 250 200 150 100 50 0 25dBuVEMF -20 -30 -40 -50 -60 -70 -80 -20 0 20 40 60 80 100 120 IF Input Level Vin(dBuEMF) N AMR : AM=30% 435 440 445 450 455 460 465 470 IF Input Frequency fin (kHz) RSSI Output Level versus IF Input Level (fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) RSSI Output Voltage Vrssi (V) Quick Charge/Discharge Current versus FSK Reference InputVoltage 80 (No input signal,Ta=25°C) 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 -20 0 20 40 60 80 100 120 IF Input Level Vi (dBuEMF) NJM2597 NJM2590 Quick Charge/Discharge Current(uA) 60 40 20 0 -20 -40 -60 -80 0 100 200 300 400 500 FSK Reference Input Voltage (mV) IF Detuning Characteristics 5 0 Detuning (dB) Carrier Sense Output Characteristics (fin=455kHz, fmod=600Hz, fdev=±4kHz,Sense Level=0.8V,Ta=25°C) 2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 0.5 1 RSSI Output Voltage Vrssi (V) 1.5 2 (Vi=60dBuEMF, fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) Carrier Sense Output Voltage Vcry (V) 60dBuVEMF -5 -10 -15 -20 -25 -30 -15 -10 -5 0 5 10 15 Relative Frequency to fin (kHz) 25dBuVEMF - 14 - Ver.2004-08-25 NJM2590/97 Operating Current versus Ambient Temperature 1000 Operating Current Iccq(mA) -3dB Limiting Sensitivity versus Ambient Temperature 40 -3dB Limiting Sensitivity Vin(lim) (dBuEMF) (No input signal,V+=1.8V) 35 30 25 20 15 10 5 0 -40 (fin=455kHz, fmod=600Hz, fdev=±4kHz,V+=1.8V) 900 800 700 600 500 400 300 200 100 0 -40 -20 0 20 40 60 80 100 Ambient Temperature Ta(°C) -20 0 20 40 60 80 100 Ambient Temperature Ta(°C) S+N versus Ambient Temperature 80 70 S+N S/N1,S/N2(dB) Demodulated Output Level versus Ambient Temperature 100 (Vi=60dBuEMF,fin=455kHz, fmod=600Hz, fdev=±4kHz,V+=1.8V) (fin=455kHz, fmod=600Hz, fdev=±4kHz,V+=1.8V) 60 50 40 30 20 10 0 -40 -20 0 20 S/N1: Vi=60dBuEMF Demodulated Output Level Vod (mVrms) 100 90 80 70 60 50 40 30 20 10 0 -40 -20 0 20 40 60 80 100 Ambient Temperature Ta (°C) S/N2: Vi=25dBuEMF 40 60 80 Ambient Temperature Ta (°C) Duty Ratio of Wave Shaped Output versus Ambient Temperature (Vi=60dBuEMF,fin=455kHz, fmod=600Hz, fdev=±4kHz,V+=1.8V) Duty Ratio of Wave Shaped output DR (%) AM Rejection Ratio versus Ambient Temperature (AM