ARA2008 Reverse Amplifier with Step Attenuator ADVANCED PRODUCT INFORMATION - Rev 0.0 FEATURES · · · · · · · Low cost integrated amplifier with step attenuator Attenuation Range: 0-58 dB, adjustable in 1dB increments via a 3 wire serial control Meets DOCSIS distortion requirements at +60dBmV output signal level Low distortion and low noise Frequency range: 5-100MHz 5 Volt operation -40 to +85 0C temperature range APPLICATIONS · · · · · MCNS/DOCSIS Compliant Cable Modems CATV Interactive Set-Top Box Telephony over Cable Systems OpenCable Set-Top Box Residential Gateway 20 Pin SSOP Package PRODUCT DESCRIPTION The ARA2008 is designed to provide the reverse path amplification and output level control functions in a CATV Set-Top Box or Cable Modem. It incorporates a digitally controlled precision step attenuator that is preceded by an ultra low noise amplifier stage, and followed by an ultra-linear output driver amplifier. This device uses a balanced circuit design that exceeds the MCNS/DOCSIS requirement for harmonic performance at a +60dBmV output level while only requiring a single polarity +5V supply. Both the input and output are matched to 75 ohms with an appropriate transformer. The precision attenuator provides up to 58 dB of attenuation in 1 dB increments via a three-wire serial interface. With external passive components, this device meets IEC 1000-4-12 and ANSI/IEEE C62.41-1991 100KHz ringwave tests, as well as IEC1000-4-5 1.2/50mS surge tests. The ARA2008 is offered in a 20-pin SSOP package. Clock Data Enable Balun Low Pass Filter ARA2008 Upstream QPSK/16QAM Modulator RAM Clock Data Transmit Enable/Disable 5-42 MHz Microcontroller with Ethernet MAC MAC Clock ROM Data 44 MHz Diplexer 54-860 MHz DoubleConversion Tuner SAW Filter QAM Receiver with FEC 10Base-T Transceiver Figure 1. Cable Modem or Set Top Box Application Diagram 10/2001 RJ45 Connector ARA2008 TXEN 32 dB 16 dB 4 dB 8 dB 2 dB 1 dB RFIN (+) RFOUT (+) RFIN (-) RFOUT (-) Buffer CLOCK DATA ENBL 8 6-bit Shift Register Control Latch Figure 2: Functional Block Diagram 1 GND GND 20 2 VDD1 VDD2 19 3 GND TXEN 18 4 GND CEXT1 17 5 RFIN (+) RFOUT (+) 16 6 RFIN (-) RFOUT (-) 15 7 GND CEXT2 14 8 ENBL N/C 13 9 DATA N/C 12 10 CLOCK GND 11 Figure 3: Pin Out - SSOP Package 2 ADVANCED PRODUCT INFORMATION - Rev 0.0 10/2001 ARA2008 Table 1: Pin Description - SSOP Package PIN N AME 1 GND 2 D ESC R IPTION PIN N AME D ESC R IPTION Ground 11 GND Ground VDD1 Supply 12 N/C No connecti on 3 GND Ground 13 N/C No connecti on 4 GND Ground 14 C EXT2 External C apaci tor 5 RFIN (+) RF (+) Input 15 RFOUT (-) RF (-) Output 6 RFIN (-) RF (-) Input 16 RFOUT (+) RF (+) Output 7 GND Ground 17 C EXT1 External C apaci tor 8 ENBL Enable 18 TXEN Transmi t Enable 9 D ATA D ata 19 V DD2 Supply 10 C LOC K C lock 20 GND Ground ADVANCED PRODUCT INFORMATION - Rev 0.0 10/2001 3 ARA2008 ELECTRICAL CHARACTERISTICS Table 2: Absolute Minimum and Maximum Ratings PAR AMETER MIN MAX U N IT Supply: VDD (pi ns 2, 15, 16, 19) 0 9 VD C RF P ower at Inputs (pi ns 5, 6) - +60 dBmV D i gi tal Interface (pi ns 8, 9, 10) -0.5 VDD+0.5 V Storage Temperature -55 +200 0 C Solderi ng Temperature - 260 0 C Solderi ng Ti me - 5 S ec Stresses in excess of the absolute ratings may cause permanent damage. Functional operation is not implied under these conditions. Exposure to absolute ratings for extended periods of time may adversely affect reliability. Table 3: Operating Ranges PAR AMETER MIN TYP MAX U N IT Supply: VDD (pi ns 2, 15, 16, 19) 4.5 5 7 VD C 0 - VDD V -40 25 85 D i gi tal Interface (pi ns 8, 9, 10) C ase Temperature 0 C The device may be operated safely over these conditions; however, parametric performance is guaranteed only over the conditions defined in the electrical specifications. Table 4: DC Electrical Specifications TA=25°C; VDD = +5.0 VDC PAR AMETER MIN TYP MAX U N IT C OMMEN TS Total Supply C urrent (pi ns 2, 15, 16, 19) - 135 15 - mA Tx enabled (TXEN hi gh) Tx di sabled (TXEN low) Total Power C onsumpti on - 675 75 - mW Tx enabled (TXEN hi gh) Tx di sabled (TXEN low) Table 5: Digital Interface Specifications TA=25°C; VDD = +5.0 VDC 4 PAR AMETER MIN TYP MAX U N IT Logi c Hi gh Input Voltage: VIN,HIGH 2.0 - VDD V Logi c Low Input Voltage: VIN,LOW 0 - 0.8 V ADVANCED PRODUCT INFORMATION - Rev 0.0 10/2001 ARA2008 Table 6: AC Electrical Specifications TA=25°C; VDD = +5.0 VDC PAR AMETER MIN TYP MAX U N IT Gai n (10 MHz) - 29 - dB 0 dB attenuati on setti ng Gai n Flatness - 1.5 - dB 5 to 65 MHz Gai n Vari ati on over Temperature - -0.006 - dB/°C Attenuati on Step Si ze - 1 - dB Maxi mum Attenuati on 58 - - dB 2nd Harmoni c D i storti on Level (10 MHz) - - -53 dB c +60 dBmV i nto 75 Ohms 3rd Harmoni c D i storti on Level (10 MHz) - - -53 dB c +60 dBmV i nto 75 Ohms 78 - - dBmV 1 dB Gai n C ompressi on Poi nt - 68.5 - dBmV Noi se Fi gure - 3.0 - dB Includes i nput balun loss Output Noi se Power Acti ve / No Si gnal / Mi n. Atten. Set. Acti ve / No Si gnal / Max. Atten. Set. - - -38.5 -53.8 dBmV Any 160 kHz bandwi dth from 5 to 42 MHz Isolati on (45 MHz) i n Tx di sable mode - 60 - dB D i fferenti al Input Impedance (Tx enabled) - 300 - Ohms Input Impedance (Tx enabled) - 75 - Ohms Input Return Loss (75 Ohms) - -15 - dB D i fferenti al Output Impedance - 300 - Ohms Output Impedance - 75 - Ohms Output Return Loss (75 Ohms) - -15 - dB Output Voltage Transi ent Tx enable / Tx di sable - 4 100 7 mVp-p 3rd Order Output Intercept ADVANCED PRODUCT INFORMATION - Rev 0.0 10/2001 C OMMEN TS Monotoni c wi th transformer wi th transformer 0 dB attenuator setti ng 24 dB attenuator setti ng 5 ARA2008 LOGIC PROGRAMMING Programming Instructions The programming word is set through a 6 bit shift register via the data, clock and enable lines. The data is entered in order with the most significant bit (MSB) first and the least significant bit (LSB) last. The enable line must be low for the duration of the data entry, then set high to latch the shift register. The rising edge of the clock pulse shifts each data value into the register. Table 7: Programming Word D ATA B IT D5 D4 D3 D2 D1 D0 Value P5 P4 P3 P2 P1 P0 Table 8: Data Description DATA D5: MSB V AL U E FU N C TION (0 = on, 1 = by pass) P5 32 dB Attenuator Bi t P4 16 dB Attenuator Bi t P3 8 dB Attenuator Bi t P2 4 dB Attenuator Bi t P1 2 dB Attenuator Bi t P0 1 dB Attenuator Bi t D4 D3 D2 CLOCK ENBL Figure 4: Serial Data Input Timing 6 ADVANCED PRODUCT INFORMATION - Rev 0.0 10/2001 D1 D0: LSB ARA2008 APPLICATION INFORMATION Output Transformer Matching the output of the ARA2008 to a 75 Ohm load is accomplished using a 2:1 turns ratio transformer. In addition to providing an impedance transformation, this transformer provides the bias to the output amplifier stage via the center tap. The transformer also cancels even mode distortion products and common mode signals, such as the voltage transients that occur while enabling and disabling the amplifiers. As a result, care must be taken when selecting the transformer to be used at the output. It must be capable of handling the RF and DC power requirements without saturating the core, and it must have adequate isolation and good phase and amplitude balance. It also must operate over the desired frequency and temperature range for the intended application. ESD Sensitivity Electrostatic discharges can cause permanent damage to this device. Electrostatic charges accumulate on test equipment and the human body, and can discharge without detection. Although the ARA2008 has some built-in ESD protection, proper precautions and handling are strongly recommended. Refer to the ANADIGICS application note on ESD precautions. ADVANCED PRODUCT INFORMATION - Rev 0.0 10/2001 7 ARA2008 ANADIGICS, Inc. 141 Mount Bethel Road Warren, New Jersey 07059, U.S.A. Tel: +1 (908) 668-5000 Fax: +1 (908) 668-5132 URL: http://www.anadigics.com E-mail: [email protected] IMPORTANT NOTICE ANADIGICS, Inc. reserves the right to make changes to its products or to discontinue any product at any time without notice. The product specifications contained in Advanced Product Information sheets and Preliminary Data Sheets are subject to change prior to a products formal introduction. Information in Data Sheets have been carefully checked and are assumed to be reliable; however, ANADIGICS assumes no responsibilities for inaccuracies. ANADIGICS strongly urges customers to verify that the information they are using is current before placing orders. WARNING ANADIGICS products are not intended for use in life support appliances, devices or systems. Use of an ANADIGICS product in any such application without written consent is prohibited. 8 ADVANCED PRODUCT INFORMATION - Rev 0.0 10/2001