NJM2590/97 455kHz INPUT FM IF DEMODULATOR GENERAL DESCRIPTION PACKAGE OUTLINE 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 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 + 14 CARRIER SENSE RSSI SENSE LEVEL OUT 13 12 11 RSSI COMP FSK CHARGE OUT 10 8 FSK COMP CHARGE RSSI IF AMP Ver.2004-08-25 9 LPF OUT LPF QUAD DET 1 2 3 4 5 6 IF IN GND DEC FSK REF QUAD IN AF OUT 7 LPF IN -1- NJM2590/97 ABSOLUTE MAXIMUM RATINGS PARAMETER (Ta=25°C) SYMBOL RATINGS UNIT Supply Voltage V+ 8.0 V Power Dissipation PD 300 mW Operating Temperature Topr - 40 to +85 °C Storage Temperature Tstg - 40 to +125 °C RECOMMENDED OPERATIONAL CONDITION PARAMETER SYMBOL TEST CONDITIONS V+ Supply Voltage (Ta=25°C) MIN. TYP. MAX. UNIT 1.6 1.8 5.5 V ELECTRICAL CHARACTERISTICS (Ta=25°C, V+=1.8V, fin=455kHz, fmod=600Hz, fdev=±4kHz) PARAMETER SYMBOL TEST CONDITIONS TYP. MAX. UNIT 440 550 660 uA (1.6) 2 (2.4) kΩ Current Consumption Iccq IF Amplifier Input Resistance Rin Signal to Noise Ratio 1 S/N1 Vi=60dBu EMF - 60 - dB Signal to Noise Ratio 2 S/N2 Vi=25dBu EMF - 30 - dB - 22 27 dBu EMF - 3dB Limiting Sensitivity No Signal MIN. Vin(lim) Demodulated Output Level V od Vi=60dBu EMF 35 40 65 mVrms AM Rejection Raito AMR Vi=60dBu EMF AM=30% - 50 - dB Duty Ratio of Wave Shaped Output DR Vi=60dBu EMF 40 50 60 % Quick Charge/Discharge Current I ch V FSK OUT=GND V LPF OUT = 0.18V 35 65 110 uA Vi=40dBu EMF 0.7 0.9 1.1 Vi=80dBu EMF 0.8 1.1 1.4 (-0.1) (0) (0.1) uA - 0.1 0.4 V (-0.1) (0) (0.1) uA I CARRIER SENSE=100uA 0.0 0.1 0.4 V V CARRIER SENSE =0.8V (-1.0) (0) (1.0) uA NJM2590 RSSI Output Voltage Vrssi 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. -2- V V FSK OUT=V+ I FSK OUT =100uA V CARRIAR SENSE =V+ 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. RSSI FSK OUT OUT CARRIER SENSE V+ 10u 100k 100k A SENSE LEVEL 14 13 11 12 0.01u 1000p 10 9 FSK COMP RSSI COMP CHARGE RSSI IF AMP 2 1 QUAD DET 3 5 4 0.1u CD 68k A 3.0k 10u 10u LPF 7 6 0.1u 51 8 68k 3300p 68k 560p 0.18V V+ 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 0.1u 1 Test Circuit 2 DR 0.1u 8 51 1 10 51 S/N1, S/N2, Vin(lim), Vod, AMR DR 100k V+ Test Circuit 3 Iccq Test Circuit 4 Vrssi 0.1u 2 1 14 A Iccq Vrssi 11 1000p 51 0.1u V+ 4 Test Circuit 5 Ich Test Circuit 6 VfskL 100uA 4 Ich 14 V+ 10u A V VfskL 9 7 V+ 10 8 0.18V -4- Ver.2004-08-25 NJM2590/97 Test Circuit 7 IfskH Test Circuit 8 IcryH 10 13 100k V 100k V V+ V+ IfskH = V/100k IcryH = V/100k Test Circuit 9 VcryL Test Circuit 10 Ilevel 100uA 13 V+ 12 A V Ilevel VcryL SENSE LEVEL 0.8V 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. CARRIER SENSE RSSI FSK SENSE LEVEL OUT OUT Circuit Diagram LPF OUT V+ 100k 10u 100k SW 0.01u 1000p 14 13 11 12 10 9 8 FSK COMP RSSI COMP GND CHARGE RSSI QUAD IF AMP 2 1 4 3 0.1 6 5 0.1u CD 7 68k 10u 3.0k 10u LPF 68k 3300p 68k 560p V+ 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 REF FSK OUT LPF OUT GND -6- Ver.2004-08-25 NJM2590/97 TERMINAL FUNCTION (Ta=25°C, V+=1.8V) Pin No. SYMBOL EQUIVARENT CIRCUIT VOLTAGE V+ 1 IF IN 1.75V 1 3 3 DEC 1.75V 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+ 4 FSK REF 4 0.9V Quadrature Detector Input. Connected with a ceramic discriminator. Built-in ESD protective circuit. V+ 5 5 QUAD IN 0.5V FM demodulated signal output. Built-in ESD protective circuit. V+ 6 Ver.2004-08-25 AF OUT 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. 6 0.2V -7- NJM2590/97 Pin No. SYMBOL EQUIVARENT CIRCUIT VOLTAGE V+ 7 LPF IN 0.18V 7 FUNCTION Low Pass Filter Input. This terminal is biased from the pin 6 through an external RC filter. Built-in ESD protective circuit. 8 8 LPF OUT 0.18V V+ 9 CHARGE - 9 V+ 10 FSK OUT 10 - V+ 11 -8- RSSI OUT 11 50mV Low Pass Filter Output. Built-in ESD protective circuit. 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. 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. Ver.2004-08-25 NJM2590/97 Pin No. SYMBOL EQUIVARENT CIRCUIT VOLTAGE Sense Level Input. Built-in ESD protective circuit. V+ 12 SENSE LEVEL 12 - V+ 13 CARRIER SENSE 13 FUNCTION - 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 Ver.2004-08-25 V+ - -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 + 8 V+ 10 4 100kΩ 10uF 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 - 10 - 4 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. - + 12 11 SENSE LEVEL 1000pF 4. 13 V+ 100kΩ 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 11 1000pF 48kΩ 5. Rext 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 where Ra=Rb=Rc or Ca=Cb=Cc 3 Each of pin7(LPF IN) and pin8(LPF OUT) has a built-in ESD protective resistor 300Ω. 300Ω + 300Ω 6 7 Ra 68kΩ Ver.2004-08-25 Rb 68kΩ Rc 68kΩ Ca 3300pF Cc 0.01uF 8 Cb 560pF - 11 - NJM2590/97 APPLICATION CIRCUIT RSSI FSK OUT OUT CARRIER SENSE V+ 100k 10u 100k 1000p 14 13 11 12 0.01u 10 9 FSK COMP RSSI COMP CHARGE RSSI QUAD IF AMP 2 1 4 3 6 5 CD 0.1 0.1u LPF 7 68k 10u 3.0k 10u IF IN 8 68k 3300p 68k 560p V+ 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 Operating Current versus Supply Voltage S+N,AM R versus Supply Voltage (No signal,Ta=25°C) (Vi=60dBuEMF, fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) 70 800 Operating Current Iccq (mA) S+N S+R, AMR (dB) 60 AMR 50 40 30 20 10 700 600 500 400 300 200 100 0 0 0 1 2 3 4 5 0 6 1 2 60 50 40 30 20 10 0 1 2 3 6 4 5 6 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 1 2 Supply Voltage V+ (V) 3 4 5 6 Supply Voltage V+ (V) Duty Ratio of Wave Shaped Output versus Supply Voltage -3dB Limiting Sensitivity versus Supply Voltage (fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) (Vi=60dBuEMF, fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) 30 60 58 25 56 Duty Ratio DR (%) -3dB Limiting Sensitivity Vin(lim) (dBuEMF) 5 (Vi=40dBuEMF, fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) 1.8 70 0 4 RSSI Output Voltage versus Supply Volgate RSSI Output Voltage Vrssi (V) Demodulated Output Vod (mVrms) Demodulated Output versus Supply Voltage (Vi=60dBuEMF, fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) 80 3 Supply Voltage V+ (V) Supply Voltage V+ (V) 20 15 10 54 52 Quick Charge ON 50 48 Quick Charge OFF 46 44 5 42 0 0 1 2 3 Supply Voltage V+ (V) Ver.2004-08-25 4 5 6 40 0 1 2 3 4 5 6 Supply Voltage V+ (V) - 13 - NJM2590/97 S+N, AMR versus IF Input Level S-Curve Characteristics (Vi=60dBuEMF, fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) 10 350 AF Output Voltage (mV) S+N 0 S+N, AMR (dB) -10 -20 -30 -40 AMR : AM=30% -50 -60 N -70 (Vi=60dBuEMF, fmod=600Hz, fdev=±4kHz,Ta=25°C) 60dBuVEMF 300 250 25dBuVEMF 200 150 100 50 -80 0 -20 0 20 40 60 80 100 120 435 440 445 IF Input Level Vin(dBuEMF) 1.4 NJM2590 0.8 NJM2597 0.6 0.4 0.2 0 -20 0 20 40 60 470 80 100 40 20 0 -20 -40 -60 -80 0 120 100 200 300 400 500 FSK Reference Input Voltage (mV) Carrier Sense Output Characteristics IF Detuning Characteristics (Vi=60dBuEMF, fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) (fin=455kHz, fmod=600Hz, fdev=±4kHz,Sense Level=0.8V,Ta=25°C) Carrier Sense Output Voltage Vcry (V) 2 0 Detuning (dB) 465 60 IF Input Level Vi (dBuEMF) 5 460 (No input signal,Ta=25°C) 80 Quick Charge/Discharge Current(uA) RSSI Output Voltage Vrssi (V) (fin=455kHz, fmod=600Hz, fdev=±4kHz,Ta=25°C) 1.6 1 455 Quick Charge/Discharge Current versus FSK Reference InputVoltage RSSI Output Level versus IF Input Level 1.2 450 IF Input Frequency fin (kHz) 60dBuVEMF -5 -10 -15 -20 25dBuVEMF -25 -30 -15 -10 -5 0 5 Relative Frequency to fin (kHz) - 14 - 10 15 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 0.5 1 1.5 2 RSSI Output Voltage Vrssi (V) Ver.2004-08-25 NJM2590/97 -3dB Limiting Sensitivity versus Ambient Temperature Operating Current versus Ambient Temperature (No input signal,V+=1.8V) 1000 900 Operating Current Iccq(mA) (fin=455kHz, fmod=600Hz, fdev=±4kHz,V+=1.8V) 40 -3dB Limiting Sensitivity Vin(lim) (dBuEMF) 800 700 600 500 400 300 200 35 30 25 20 15 10 5 100 0 0 -40 -20 0 20 40 60 80 -40 100 -20 0 Ambient Temperature Ta(°C) (fin=455kHz, fmod=600Hz, fdev=±4kHz,V+=1.8V) Demodulated Output Level Vod (mVrms) S+N S/N1,S/N2(dB) S/N1: Vi=60dBuEMF 50 40 30 S/N2: Vi=25dBuEMF 20 10 0 -40 -20 0 20 40 60 80 100 80 90 80 70 60 50 40 30 20 10 0 100 -40 -20 0 Ambient Temperature Ta (°C) 20 40 60 80 100 Ambient Temperature Ta (°C) Duty Ratio of Wave Shaped Output versus Ambient Temperature AM Rejection Ratio versus Ambient Temperature (Vi=60dBuEMF,fin=455kHz, fmod=600Hz, fdev=±4kHz,V+=1.8V) (AM<30%, fin=455kHz, fmod=600Hz, fdev=±4kHz,V+=1.8V) 80 60 58 AM Rejection Ratio AMR (dB) Duty Ratio of Wave Shaped output DR (%) 60 (Vi=60dBuEMF,fin=455kHz, fmod=600Hz, fdev=±4kHz,V+=1.8V) 100 70 60 40 Demodulated Output Level versus Ambient Temperature S+N versus Ambient Temperature 80 20 Ambient Temperature Ta(°C) 56 54 52 50 48 46 44 42 40 -40 -20 0 20 40 60 Ambient Temperature Ta (°C) Ver.2004-08-25 80 100 70 60 50 40 30 20 10 0 -60 -40 -20 0 20 40 60 80 100 Ambient Temperature Ta (°C) - 15 - NJM2590/97 RSSI Output Resistance versus Ambient Temperature Quick Charge/DischargeCurrent versus Ambient Temperature (VFSKOUT =GND, VLOFOUT=0.18V,V+=1.8V) RSSI Output Resistance (kΩ) Quick Charge/Discharge Current Ich (uA) (Vi=40dBuEMF,fin=455kHz, fmod=600Hz, fdev=±4kHz,V+=1.8V) 60 100 90 80 70 60 50 40 30 20 10 0 50 40 30 20 10 0 -40 -20 0 20 40 60 80 100 Ambient Temperature Ta (°C) -40 -20 0 20 40 60 80 100 Ambient Temperature Ta (°C) RSSI Output Voltage versus Ambient Temperature (Vi=40dBuEMF,fin=455kHz, fmod=600Hz, fdev=±4kHz,V+=1.8V) RSSI Output Voltage Vrssi (V) 1.8 1.6 1.4 1.2 1 0.8 1.6V 0.6 1.8V 0.4 3.0V 0.2 5.0V 0 -40 -20 0 20 40 60 80 100 Ambient Temperature Ta (°C) [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. - 16 - Ver.2004-08-25