CXA1741Q IF Amplifier for Analog Cellular Communications For the availability of this product, please contact the sales office. Description The CXA1741Q is an analog cellular(TACS/ NTACS) FM IF IC which incorporates an IF filter. Features • Incorporates a ceramic filter function, which is normally mounted externally. • Quadrature detection discriminator function. • This IC has almost all IF functions and is ideal for reduction in set size because of few external parts required. • The built-in filter permits mode changeover between TACS and NTACS. • Wide operating voltage range (2.7 V to 3.6 V) and low current consumption (Icc=10 mA (typ.) when Vcc= 3 V). • Wide range and excellent temperature characteristics for the RSSI (receiving signal strength indicator). 40 pin QFP (Plastic) Absolute Maximum Ratings (Ta = 25°C) • Supply voltage VCC 5 V • Operating temperature Topr –35 to +85 °C • Storage temperature Tstg –65 to +150 °C • Allowable power dissipation PD 500 mW Operating Conditions Supply voltage VCC 2.7 to 3.6 V Applications Ideally suited for cellular phones, particularly handheld sets. Structure Bipolar silicon monolithic IC Sony reserves the right to change products and specifications without prior notice. This information does not convey any license by any implication or otherwise under any patents or other right. Application circuits shown, if any, are typical examples illustrating the operation of the devices. Sony cannot assume responsibility for any problems arising out of the use of these circuits. —1— E94245-TE CXA1741Q Block Diagram and Pin Configuration T3 MIXADJ1 MIXADJ2 MIXPS MIXIN GND VCC IFPS IFIN GND (Top View) 30 29 28 27 26 25 24 23 22 21 20 XTALIN T4 31 RF AMP PSN 19 XTALOUT T5 32 PSN MIXER VCC1 33 GND1 34 18 AGCPS 1/2 17 VREF OSC BPF0 T6 35 16 RSSIPS AGC FADJ1 36 15 T2 BPF1 FADJ2 37 14 RSDETPS RSSI SGND 38 13 T1 BIAS LIM DET 5 6 7 8 9 10 LIMPS 4 IF2 3 GADJ(RSSI) 2 RSSI 1 AUDIO 11 VCC2 BPFO BPFPS2 40 NC 12 GND2 SW(TACS/NTACS) BPFPS1 39 Note) Pins 21 and 25 are connected via the IC internal wiring. Pins 12, 21 and Pins 25, 34 are connected via IC internal resistors. When designing a PCB, ensure that all GND pins of IC are connected to the GND on PCB with its connection wiring distance minimized. —2— CXA1741Q Pin No. Symbol 1 SW TACS NTACS ( Pin voltage DC AC ) 0V OPEN HIGH (3 V) I/O resistance Equivalent circuit 31 Description Changeover switch for built-in filter. TACS for Low; NTACS for High. 20µA 50k 1 50k VREF 34 2 3 4 5 NC BPFO GND Not internally connected. BPF output monitor. Not used normally. Connected to the LIM and RSSI inputs in the IC. 1.8 V 33 147 3 4 5 34 B.P.F N.F.B Network LIM RSSI 6 AUDIO 2.1 V 11 1k 6 12 —3— Outputs an AUDIO signal which is FM-detected. CXA1741Q Pin No. Symbol 7 RSSI Pin voltage DC AC I/O resistance Equivalent circuit Description 1.2 V RSSI output. Outputs a DC voltage in accordance with the signal input to the RF amplifier. 11 147 7 12 8 GADJ 0.2 V Adjusts the RSSI amplifier gain (varies the resistance so as to obtain a linear RSSI output). 147 147 8 9 IF2 7 0.9 V Limiter operation monitor. Not used normally. 11 147 9 12 10 LIMPS 1.8 V 11 10 12 —4— Connects a limiter integrating capacitor. CXA1741Q Pin voltage DC AC Pin No. Symbol 11 VCC2 3.0 V 12 13 GND2 T1 0V 14 I/O resistance Equivalent circuit Description Power supply. Supplies current to the LIM, DET, and RSSI circuits. Ground. IC operation check. RSDETPS 1.4 V 11 Connects an RSSI detector integrating capacitor. 147 14 12 15 T2 16 RSSIPS IC operation check. 1.8 V Connects an RSSI integrating capacitor. 11 16 12 17 VREF 1.3 V 33 17 34 reference voltage used in the internal circuit —5— Monitor for the reference voltage used in the internal circuit. When connected to an external capacitor, this pin also functions to lower the reference voltage dynamic impedance. CXA1741Q Pin No. Symbol 18 AGCPS Pin voltage DC AC I/O resistance Equivalent circuit 0.2 V Description 33 Connects an AGC integrating capacitor. 18 VREF 34 15 19 XTALOUT 2.9 V 24 147 20 10k 15p 10k 19 20 XTALIN 2.9 V 25 21 22 GND IFIN 21 0V 1.3 V 24 23 IFPS 1.3 V 22 23 1.5k 1.5k VREF 21 24 VCC 3.0 V 25 GND 0V Connect a crystal oscillator to form a Colpitts-type oscillator circuit. When an external oscillator is used, its input must be connected to Pin 20. 25 Ground. RF amplifier input. The relationship between IFIN (Pin 22) and IFPS (Pin 23) is designed so that the IC internal stray capacitance is small. Therefore, if Pins 22 and 23 are used for balance input, the common-mode rejection deteriorates. Power supply. Supplies current to the RF AMP, MIXER, OSC, and 1/2 DIVIDER circuits. Ground. —6— CXA1741Q Pin No. Symbol 26 MIXIN Pin voltage DC AC I/O resistance Equivalent circuit Description 1.3 V RF AMP output monitor. Connected to the MIXER input in the IC. 27 27 MIXPS 1.3 V 26 MIXER 28 MIX ADJ2 0.1 V 29 MIX ADJ1 0.1 V RF AMP Balance adjustment for mixers 1 and 2. 4k 4k 4k 4k 28 29 660 660 30 31 32 33 T3 T4 T5 VCC1 IC operational check. 34 35 GND1 T6 0V 36 FADJ1 2.2 V 3.0 V Power supply. Supplies current to the PSN, BPF, and BIAS circuits. Ground. IC operational check. 147 36 37 FADJ2 37 1.5 V 147 —7— When the resistance value of an external resistor connected between Pins 36 and 37 is varied, the center frequency of the BPF in the IC changes accordingly. CXA1741Q Pin No. Symbol 38 SGND Pin voltage DC AC I/O resistance Equivalent circuit 1.8 V Description 33 38 34 Monitor for the pseudground voltage used in the internal circuits. When connected to an external capacitor, this pin also functions to lower the reference voltage dynamic impedance. B.P.F signal reference voltage 39 BPFPS1 1.1 V 33 39 40 BPFPS2 1.2 V 40 34 reference voltage used for B.P.F —8— Monitor for the reference voltage used by the BPF. When connected to an external capacitor, these pins also function to lower the reference voltage dynamic impedance. CXA1741Q Electrical Characteristics Item Symbol Current consumption - 1 ICC-11 Current consumption - 2 ICC-24 Current consumption - 3 ICC-33 Pin current Pin 1 - Low Pin current Pin 1 - High Pin current Pin 19 0dBm = 50Ω, 1mW VCC = 3V, Ta = 25°C FOSC = 89.9 MHz Conditions fin = 45 MHz, -30 dBm Pin 11 fin = 45 MHz, -30 dBm Pin 24 fin = 45 MHz, -30 dBm Pin 33 Min. Typ. Max. Unit 0.8 1.1 1.5 mA 2 2.9 3.8 mA 3.8 5.3 7 mA IIL 0V -14 -10 -7 µA IIH 3V 15 23 30 µA I19 Crystal osc. 89.9 MHz 0.4 0.6 mA Pin voltage - Pin 17 V17 1.2 1.25 1.3 V Pin voltage - Pin 38 V38 1.6 1.8 2 V Pin voltage - Pin 39 V39 1 1.17 1.4 V Pin voltage - Pin 40 V40 1 1.2 1.4 V OSC output swing Pin 19 VOSC 70 93 130 mV rms Crystal osc. 89.9 MHz Wide BPF; TACS mode (Pin 1=Low) BPF output voltage - 1 VTG1 fin = 45 MHz, -50 dBm 100 162 220 BPF output voltage - 2 VTG2 fin = 45 MHz, -20 dBm 220 291 360 IF1 output voltage VTIF fin = 45 MHz, -20 dBm 80 89 100 Mixer image rejection level VIMAG fin = 44.9 MHz, -30 dBm 30 100 BPF 6 dB bandwidth BW6dB 26 30 BPF 40 dB bandwidth BW40dB BPF extraband attenuation ATT40K FM detection level FMDET AM rejection ratio AMR Vin = -50 dBm, Swept with fin = 45 MHz regarded as the center Vin = -50 dBm, Swept with fin = 45 MHz regarded as the center fo ±40 kHz fin = 45 MHz, -30 dBm, fmod=1 kHz, Dev. = 5.6 kHz, Dev. = 5.6 kHz, used LPF 20 kHz fin = 45 MHz, -30 dBm, fmod = 1 kHz, Mod = 80% used LPF 20 kHz —9— 150 mV rms mV rms mV rms mV rms kHz 47 kHz 56 dB 194 250 mV rms -27 -20 dB CXA1741Q Item Audio output distortion Symbol Conditions THD fin = 45 MHz, -30 dBm, fmod = 1 kHz, Dev. = 8 kHz, used LPF 20 kHz Min. Typ. Max. Unit 3.7 6 % 1 1.15 1.3 V RSSI output voltage - 11 RSSI11 No input RSSI output voltage - 12 RSSI12 fin = 45 MHz, -60 dBm 1.65 1.93 2.2 V RSSI output voltage - 13 RSSI13 fin = 45 MHz, -20 dBm 2.4 2.67 2.8 V 4.5 20 mV rms 13.5 16 kHz Narrow BPF; NTACS mode (Pin 1=High) Mixer 3rd inter-modulation IM3 f1 = 45.02 MHz, -30 dBm, f2 = 45.04 MHz, -30 dBm Vin = -50 dBm, Swept with fin = 45 MHz regarded as the center Vin = -50 dBm, Swept with fin = 45 MHz regarded as the center BPF 6 dB bandwidth BW6dB BPF 40 dB bandwidth BW40dB BPF extraband attenuation ATT20K fo ±20 kHz FM detection level FMNDET AM detection level AMRN Audio output distortion THDN RSSI output voltage - 21 23 kHz 62 dB 99 mV rms 16 dB 2.8 % RSSI21 No input 1.09 V RSSI output voltage - 22 RSSI22 f = 45 MHz, -60 dBm 1.91 V RSSI output voltage - 23 RSSI23 f = 45 MHz, -20 dBm 2.65 V fin = 45 Mhz, -30 dBm, fmod = 1 kHz, Dev. = 3 kHz, Used LPF 20 kHz fin = 45 Mhz, -30 dBm, fmod = 1 kHz, Mod = 80%, Used LPF 20 kHz fin = 45 Mhz, -30 dBm, fmod = 1 kHz, Dev. = 3 kHz, Used LPF 20 kHz Others Equivalent input resistance Pin 22 Equivalent input capacitance Pin 22 BPF•fo temperature characteristics TACS mode BPF•fo temperature characteristics NTACS mode RIN f = 55 MHz 1.4 kΩ CIN f = 55 MHz 4.7 pF Ta = -30 to + 70°C 1.5 kHz Ta = -30 to + 70°C 1.5 kHz —10— CXA1741Q Measurement Circuit 6 10 104 S6 101 1.5µ 103 47 S5 104 100 500 28 27 26 25 24 23 22 21 20 31 102 29 89.9MHz 10p 30 6p RF AMP PSN 19 32 0.47µ PSN 102 MIXER 33 18 104 104 34 1/ 2 BPF0 17 OSC 223 16 35 AGC 56K 15 36 S4 BPF1 37 14 RSSI VR10K 104 1k 104 38 13 BIAS S3 LIM 5 DET 39 12 40 11 104 4 5 6 7 8 9 102 47k 220k 1 2 —11— 3 10 4 103 3 S2 2 1k 1 104 104 S1 Vcc 3V 7 CXA1741Q Application Circuit Oscillator circuit 45MHz IN Vcc 7p 1.5µ 100p 0.1µ 0.1µ 30 29 28 27 26 25 24 23 22 109.9MHz RF AMP PSN Vcc 19 32 PSN MIXER 33 Vcc 0.33µ 20 31 0.1µ 10p 21 34 18 1/2 17 OSC 0.047µ 0.1µ BPF0 16 35 AGC 0.1µ 20k 15 36 BPF1 51k 37 2.2µ 14 RSSI 38 0.1µ 13 BIAS LIM DET 39 12 40 11 2.2µ Vcc 2.2µ 1 2 3 4 5 6 7 8 9 10 0.1µ 94k 220k 82p TACS 50K 0.1µ 47k NTACS 50K AUDIO OUT RSSI OUT Vcc Note: Use a 0.1µF capacitor for Pin 14 decoupling. The IC malfunctions at a capacitance of 0.047µF or lower. The oscillator circuit must be changed according to the crystal characteristics. When designing PCB pattern, make PCB pattern so that Pins 3, 4, and 5 are connected correlatively. This makes IC other than TACS/NTACS standard possible to use without changing PCB pattern. Application circuits shown are typical examples illustrating the operation of the devices. Sony cannot assume responsibility for any problems arising out of the use of these circuits or for any infringement of third party patent and other right due to same. —12— CXA1741Q Description of Operation A 45 MHz IF signal is input to Pin 22. This input signal is amplified at the RF AMP and then mixed with the local oscillation signals from the oscillator at the mixer to change the signal frequency to 50 kHz. When a crystal resonator or like external circuit is connected to Pins 19 and 20, the oscillator can be self-executed by composing a Colpitts-type oscillation circuit. It can be also used with an external local oscillation signal applied to Pin 20. The internal BPF eliminates any interference from the converted 50 kHz signal, which is then fed to the limiter and RSSI circuit. The limiter eliminates an amplitude component from the signal. The resulting signal is then detected at the quadrature FM detector circuit, and Pin 6 outputs an audio signal. The RSSI circuit detects the RF AMP input signal voltage and generates from Pin 7 the DC voltage where the detected voltage value is logarithmically compressed. SW (Pin 1) can switch the NTACS and TACS modes. 45MHz IN IFIN 30 29 28 27 26 25 24 23 22 21 20 31 RF AMP PSN 19 XTALOUT 32 PSN MIXER 33 34 18 1/2 17 OSC BPF0 16 35 AGC 15 36 BPF1 37 14 RSSI 38 13 BIAS LIM DET 39 12 40 11 1 TACS 2 NTACS Vcc 3 4 5 6 AUDIO OUT 7 8 RSSI OUT AUDIO RSSI output output Signal Flow —13— XTALIN 9 10 Crystal Oscillator Circuit CXA1741Q 1) Power supply Power supply pins (Pins 11, 24, and 33) must be decoupled with the shortest distance. 2) Oscillator The figures below show how to use the CXA1741Q oscillator. Vcc Vcc Vcc C2 20 19 20 Crystal 600mVp-p or more 19 C1 L Vcc (a) Inputting a local oscillation signal from an external circuit. The circuit current varies with the externally fed signal amplitude. The reason is that the AGC circuit, which works to maintain the oscillation amplitude constant when a Colpitts-type oscillator circuit is formed, also operates when an external local oscillation signal is input. (b) Configuring a Colpitts-type oscillator circuit. The C1, C2, and L must be changed according to the crystal characteristics. The oscillation Tr in the IC is internally subjected to AGC so that the oscillation level at Pin 19 is not likely to be affected by temperature or supply voltage fluctuations. 3) Mixers Since the BPF in the IC has an fo value as low as 50 kHz, the IC employs an image rejection type of mixer having an enhanced interference elimination capability. Therefore, the two internal mixers must be accurately adjusted so that their gains are equal. Normally, an adequate degree of image rejection is provided without using Pins 28 and 29. However, when they are used for adjustment purposes, an increased degree of image rejection will result. 500Ω 29 28 —14— CXA1741Q 4) BPF The passband frequency of the built-in filter should be adjusted. For adjustment method, adjust skirt characteristics of band-pass filter to be symmetric with respect to the center frequency. Or observe the AUDIO output at Pin 7 and adjust the variable resistor between Pins 36 and 37 so as to minimize the AUDIO output distortion. 36 37 5) RSSI (receiving signal strength indicator) RSSI detects the input signal level. The IC generates a DC voltage output, which is nearly proportional to the logarithmic value of RF input level. The output level can be varied by adjusting GADJ (Pin 8) resistance value. Adjust the resistance value so that saturation does not occur when the input level is high. V Vcc (approx. 0.5V) Adjust for this curve. RSSI 7 RSSI 0 Input level dBm —15— 8 CXA1741Q Notes on Operation 1. This IC must be handled with care because it is extremely susceptible to electrostatic surges. Particularly, IFIN (Pin 22) is easily affected by electrostatic surges. 2. When the 0.1µF capacitor connected to Pin 14 has a capacitance of 0.047µF or less, the IC malfunctions. Be sure that the employed capacitor has an excellent temperature characteristics. 3. When the capacitance value of the 0.1µF capacitor connected to Pin 38 is decreased, the IC characteristics begin to slightly deteriorate. Further, a capacitance value increase would not improve the IC characteristics accordingly. 4. When the capacitance value of the 0.1µF capacitor connected to Pin 40 is decreased, the IC characteristics slightly deteriorate. 5. Vcc1 (Pin 33) supplies the power to the reference bias voltage generator circuit which is necessary for IC operations. If the same VCC power supply is not provided for Vcc voltages to be applied to Pins 11, 19, 24, and 33, ensure that the Pin 33 Vcc rises first. 6. Be sure that nothing is connected to Pins 13, 15, 30, 31, 32, and 35. 7. Resistance between Pins 36 and 37 The signal of 45 MHz, –50 dBm is input from Pin 22 (IFIN) and the level of Pin 3 (BPFOUT) is read. After that when this frequency is varied to +8 kHz and –8 kHz respectively, resistance value between Pins 36 and 37 is varied to be the same attenuation level. 8. Inductance between Pins 26 and 27 Adjustment must be made so that a 45 MHz parallel resonance circuit is formed by the inductor between Pins 26 and 27 and the IC stray capacitor. This adjustment assures that an increased mixer conversion gain is provided at a low input signal level. Once the optimum value is obtained upon PCB conductive pattern determination, readjustment is unnecessary after sample changes. 9. Pin 19 resonance circuit This circuit must be adjusted for the crystal oscillation frequency. Once the optimum value is obtained upon PCB conductive pattern determination, readjustment is unnecessary after sample changes. —16— CXA1741Q Example of Representative Characteristics The following characteristic curves are measured after IC adjustment. If the IC is not properly adjusted, the resulting characteristics are not close to the representative characteristics presented below. When making measurements, observe precautions 7, 8, and 9 under "Notes on Operation". Sensitivity of adjust R vs fo 60 BPF•fo [kHz] 55 50 45 52 54 56 58 60 62 64 66 68 70 72 Total resistance value [k Ω ] Pass Band Shift by the BPF•fo adjustment 20 NTACS•BW 20dB [kHz] 19 18 17 16 15 14 45 50 BPF•fo [kHz] —17— 55 60 CXA1741Q [dB] TACS 40 Response NTACS 30 20 Ta=25°C Vcc=3.3V 10 0 CXA1741•SINAD TACS f=45MHz, FM Modulation Dev. 5.7kHz Audio 1kHz CCITT weighting NTACS f=45MHz, FM Modulation Dev. 3kHz Audio 1kH CCITT weighting –120 –100 –80 –60 –40 –20 [dBm] Input level [dB] S 0 CXA1741•TACS CCITT weighting f=45MHz FM Modulation Dev. 5.7kHz Audio 1kHz –10 Response –20 Ta=25°C VCC=3.3V –30 –40 D –50 N –60 –120 –100 –80 –60 –40 –20 [dBm] Input level [dB] S 0 CXA1741•NTACS CCITT weighting f=45MHz FM Modulation Dev. 3kHz Audio 1kHz –10 Response –20 Ta=25°C VCC=3.3V –30 D –40 –50 N –60 –120 –100 –80 –60 –40 Input level —18— –20 [dBm] CXA1741Q Selectivity characteristics D/U [dB] NTACS 70 60 50 VCC=2.7V Ta=25°C 20dB SINAD=–96dBm TACS 40 30 20 10 –50 –40 –30 –20 –10 +10 +20 +30 +40 +50 45MHz±∆f [kHz] Image rejection characteristics D/U [dB] 80 NTACS 70 VCC=2.7V Ta=25°C 60 50 40 TACS 30 20 10 –40 –30 –20 –10 0 +10 +20 +30 +40 44.9MHz±∆f [kHz] Detuning characteristics Distortion [%] TACS Deviation 5.7kHz Audio 1kHz CCITT weighting NTACS Deviation 3kHz Audio 1kHz CCITT weighting 14 12 NTACS 10 VCC=2.7V Ta=25°C 8 6 TACS 4 2 –10 –8 –6 –4 –2 0 +2 45MHz±∆f [kHz] —19— +4 +6 +8 +10 CXA1741Q RSSI characteristics-1 RSSI characteristics-2 [V] [V] 3.0 3.0 TACS VCC=2.7V 70°C 25°C –30°C 2.5 RSSI output voltage 2.5 RSSI output voltage NTACS VCC=2.7V 70°C 25°C –30°C 2.0 1.5 1.0 0.5 2.0 1.5 1.0 0.5 Signal input from Pin 22 (IF IN) Voltage measurement at Pin 7 0 –100 –50 0 0 dBm IF input voltage –100 –50 0 dBm IF input voltage Modulation characteristics Distortion [dB] –20 –30 IFIN to Audio OUT f=4.5Mhz, –40dBm Audio=1kHz CCITT weighting VCC=3.3V Ta=25°C I/O characteristics BPF output [dBV] 0 IFIN to BPF OUT F0=45MHz F1=45.02MHz F2=45.04MHz –20 Ta=25°C VCC=3.3V NTACS TACS IM3 –40 –40 –60 –50 2 4 6 Deviation [kHz] 8 10 –80 –100 –90 –80 –70 –60 –50 IF input [dB] Audio frequency response Response [dB] +2 0 –2 –4 0dB normalized at 1kHz TACS deviation 5.7kHz NTACS deviation 3kHz IFIN 45MHz, –40dBm Ta=25°C, VCC=3.3V NTACS TACS –6 –8 –10 –12 –14 10 100 1k Frequency [Hz] —20— 10k 100k –40 –30 –20 –10 0 CXA1741Q Unit : mm 40PIN QFP (PLASTIC) + 0.35 1.5 – 0.15 + 0.1 0.127 – 0.05 9.0 ± 0.4 + 0.4 7.0 – 0.1 0.1 21 30 20 31 A 11 40 1 + 0.15 0.3 – 0.1 0.65 10 ± 0.12 M (8.0) + 0.15 0.1 – 0.1 0.5 ± 0.2 Package Outline DETAIL A PACKAGE STRUCTURE PACKAGE MATERIAL EPOXY RESIN SONY CODE QFP-40P-L01 LEAD TREATMENT SOLDER / PALLADIUM PLATING EIAJ CODE ∗QFP040-P-0707 LEAD MATERIAL COPPER / 42 ALLOY PACKAGE WEIGHT 0.2g JEDEC CODE —21—