ARA1400 Reverse Amplifier with Step Attenuator Data Sheet - Rev 2.1 FEATURES • Low cost integrated monolothic GaAs amplifier with step attenuator • Attenuation Range: 0-56 dB, adjustable in 4 dB increments via a 4 wire parallel control • Meets DOCSIS distortion requirements at +60 dBmV output signal level • Low distortion and low noise • Frequency range: 5-100 MHz • 5 Volt operation • 0 to +85 °C temperature range APPLICATIONS • MCNS/DOCSIS Compliant Cable Modems • CATV Interactive Set-Top Box • Telephony over Cable Systems • OpenCable Set-Top Box • Residential Gateway S12 Package 28 Pin SSOP with Heat Slug PRODUCT DESCRIPTION The ARA1400 is a GaAs IC 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. The device is capable of meeting the MCNS/DOCSIS requirements for 4 harmonic performance at a +60dBmV output level while requiring only a single polarity +5V supply. Both the input and the output are single-ended and matched to 75 Ohms, and a precision attenuator provides up to 56 dB of attenuation in 4 dB increments. The device is offered in a 28-pin SSOP package featuring a heat slug on the bottom of the package. Attenuation Control LPF ARA1400 Balun 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 03/2004 RJ45 Connector ARA1400 RFOUT1 ATT IN ATT OUT RFIN2 56 dB 4 dB step digital attenuator section RFIN ISET1 32 dB 16 dB 8 dB ISET2 4 dB Figure 2: Functional Block Diagram 1 GND 2 N/C 3 ATT IN 4 RFOUT1 5 VREF1 6 ATT ACG1 ATTACG2 23 7 ATT ACG1 ATTACG2 22 8 ATT ACG1 ATTACG2 21 9 ATT ACG1 ATTACG2 20 10 RFIN RFOUT 19 11 ISET1 VREF2 18 12 VATT VA2 17 13 32 dB 4 dB 16 14 16 dB 8 dB 15 ATTOUT 28 ISET2 27 RFIN2 26 Tx 25 ATTACG3 24 Figure 3: Pinout 2 RFOUT AMP AMP Data Sheet - Rev 2.1 03/2004 Tx ARA1400 Table 1: Pin Description PIN NAME DESCRIPTION PIN NAME DESCRIPTION 1 GND Ground 15 8 dB 82 dB Attenution Control Bit 2 N/C No Connection (1) 16 4 dB 4 dB Attenution Control Bit 3 ATTIN Attenuator Input (2) 17 V A2 4 RFOUT1 Amplifier A1 Output and Supply 18 VREF2 Reference Voltage for Amplifier A2 5 VREF1 Reference Voltage for Amplifier A1 19 RFOUT RF Output from Switch (2) 6 ATTACG1 Attenuator AC Ground 1 (3) 20 ATTACG2 Attenuator AC Ground 2 (3) 7 ATTACG1 Attenuator AC Ground 1 (3) 21 ATTACG2 Attenuator AC Ground 2 (3) 8 ATTACG1 Attenuator AC Ground 1 (3) 22 ATTACG2 Attenuator AC Ground 2 (3) 9 ATTACG1 Attenuator AC Ground 1 (3) 23 ATTACG2 Attenuator AC Ground 2 (3) 10 RFIN Amplifier A1 Input (4) 24 ATTACG3 Attenuator AC Ground 3 (3) 11 ISET1 Amplifier A1 Current Adjust 25 Tx 12 VATT Attenuator Supply 26 RFIN2 Amplifier A2 Input (4) 13 32 dB 32 dB Attenution Control Bit 27 ISET2 Amplifier A2 Current Adjust 14 16 dB 16 dB Attenution Control Bit 28 ATTOUT Amplifier A2 Supply Output Switch Control Attenuator Output (2) Notes: (1) All N/C pins should be grounded. (2) Pins should be AC-coupled. No external DC bias should be applied. (3) Pins should be AC-grounded. No external DC bias should be applied. (4) Pins should be AC-coupled from the RF path, and should be pulled to ground through a resistor. Data Sheet - Rev 2.1 03/2004 3 ARA1400 ELECTRICAL CHARACTERISTICS Table 2: Absolute Minimum and Maximum Ratings PARAMETER MIN MAX UNIT 0 9 VD C Amplifier Reference Voltages (pins 5, 18) -2.5 VSUP 2 VD C RF Power at Amplifier Inputs (pins 10, 26) - +60 dBmV Attenuator Controls (pins 13, 14, 15, 16) 0 6 V Output Switch Control (pin 25) 0 6 V -55 +200 °C Soldering Temperature - 260 °C Soldering Time - 5 S ec Analog Supply: VSUP (pins 4, 12, 17) Storage Temperature 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. Notes: 1. Pins 3, 19, and 28 should be AC-coupled. No external DC bias should be applied. 2. Pins 11 and 27 should be grounded or pulled to ground through a resistor. No external DC bias should be applied. 3. Pins 6, 7, 8, 9, 20, 21, 22, 23 and 24 should be AC-grounded. No external DC bias should be applied. 4. Pins 10 and 26 should be AC-coupled from the RF path, and should be pulled to ground through a resistor. Table 3: Operating Ranges PARAMETER MIN TYP MAX UNIT Amplifier Supply: VDD (pins 4, 17) 4.5 5 7 VD C Attenuator Supply: VATTN (pin 12) VDD-0.5 5 7 VD C Attenuator Controls (pins 13, 14, 15, 16) 0 - 5.5 V Amplifier Reference Voltages (pins 5, 18) - 1.75 - VD C Output Switch Control (pin 25) 0 - 5.5 V Case Temperature 0 25 85 °C The device may be operated safely over these conditions; however, parametric performance is guaranteed only over the conditions defined in the electrical specifications. 4 Data Sheet - Rev 2.1 03/2004 ARA1400 Table 4: DC Electrical Specifications (TA = 25 °C; VDD,VATTN = +5.0 VDC) PARAMETER MIN TYP MAX UNIT Amplifier A1 Current (pin 4) - 74 95 mA Amplifier A2 Current (pin 17) - 108 130 mA Attenuator Current (pin 12) - 12 20 mA Total Power Consumption - 0.97 1.23 W COMMENTS Table 5: AC Electrical Specifications (TA = 25 °C; VDD, VATTN = +5.0 VDC; Tx = 0 V (switch closed), Tx = +5 V (switch open)) PARAMETER MIN TYP MAX UNIT COMMENTS Gain (10 MHz) 30 32 33 dB 0 dB attenuation setting Gain Flatness - 0.75 - dB 5 to 100 MHz Gain Variation over Temperature - -0.006 - dB/°C 3.6 7.7 15.3 31.0 3.9 8.0 15.7 31.5 4.2 8.3 16.1 32.0 Switch Isolation at 45 MHz - 35 Harmonics (fo = 10MHz) 2fo 3fo - 3rd Order Output Intercept Attenuation Steps 4 dB 8 dB 16 dB 32 dB dB Monotonic 30 dB Difference in output signal level between active and standby -57 -64 -52 -56 dB c fo power = +60 dBmV into 75 Ohms 78 - - dBmV 1 dB Gain Compression Point - 70 - dBmV Noise Figure - 1.7 2.5 dB Output Noise Power Active / No Signal / Min. Atten. Set. Active / No Signal / Max. Atten. Set. - - -37.6 -54.6 dBmV Input Impedance - 75 - Ohms Any 160 kHz bandwidth from 5 to 42 MHz Note: As measured in ANADIGICS test fixture. Data Sheet - Rev 2.1 03/2004 5 ARA1400 continued: AC Electrical Specifications (TA = 25 °C; VDD, VATTN = +5.0 VDC; Tx = 0 V (switch closed), Tx = +5 V (switch open)) PARAMETER MIN TYP MAX UNIT COMMENTS Input Return Loss (75 Ohm characteristic impedance) - -20 -15 dB Output Impedance - -20 -12 -15 -10 Ohms Switch closed Switch open Output Return Loss (75 Ohm characteristic impedance) - -17 -15 -12 -10 dB Switch closed Switch open Output Voltage Transient switch closed / switch open - 4 7 mVp-p Note: As measured in ANADIGICS test fixture. Table 6: Logic Interface Specifications (TA = 25 °C; VDD, VATTN = +5.0 VDC) PARAMETER MIN TYP MAX UNIT Attenuator Control Logic VIN,LOW VIN,HIGH 0 2.7 - 0.5 5.5 V - 5K - Ohms 0 2.8 - 1 5.5 V - 10 K - Ohms Attenuator Control Impedance Output Switch Control Logic VIN,LOW VIN,HIGH Output Switch Control Impedance COMMENTS Bypasses atten. stage Enables atten. stage Switch closed Swicth open Table 7: Attenuator Logic ATTENUATION (dB) 0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 4 dB Logic Input (pin 16) L H L H L H L H L H L H L H L H 8 dB Logic Input (pin 15) L L H H L L H H L L H H L L H H 16 dB Logic Input (pin 14) L L L L H H H H L L L L H H H H 32 dB Logic Input (pin 13) L L L L L L L L H H H H H H H H Notes: “L” = logic low, “H” = logic high 6 Data Sheet - Rev 2.1 03/2004 Data Sheet - Rev 2.1 03/2004 RF Input (75 Ohms) 3.9 Ohms 0.1uF 1uF +5 V 1uF 620 Ohms 1.8K Ohms 1uF 3.3K Ohms 32 dB 1pF 5K Ohms 0.1uF 1uF 0.1uF 20 Ohms 0.1uF 0.1uF 10uH 16 dB 14 13 12 11 10 9 8 7 6 5 4 3 2 1 16 dB 32 dB VATT ISET1 RFIN ATTACG1 ATTACG1 ATTACG1 ATTACG1 VREF1 RFOUT1 ATTIN N/C GND ARA1400 28 25 26 27 8 dB 4 dB VA2 VREF2 RFOUT ATTACG2 ATTACG2 ATTACG2 ATTACG2 15 16 17 18 19 20 21 22 23 ATTACG3 24 Tx RFIN2 ISET2 ATTOUT 5K Ohms +5 V 10uH 20 Ohms 1uF 0.1uF 0.1uF 0.1uF 0.1uF 1uF 0.1uF 3.3K Ohms 1uF 1.8K Ohms 620 Ohms 1uF 0.1uF 10K Ohms 5K Ohms RF Output (75 Ohms) Output Switch Control (0 / +5 V) Note: Output Switch Closed: Output Switch Control = 0 V Output Switch Open: Output Switch Control = +5 V 8 dB 1uF 4 dB +5 V ARA1400 Figure 4: Test Circuit 7 ARA1400 APPLICATION INFORMATION Amplifier Enable / Disable The ARA1400 includes two amplification stages that each can be shut down through external control pins VREF1 and VREF2 (pins 5 and 18, respectively). By applying a typical bias of 1.75 Volts to these pins, the amplifiers are enabled. In order to fully disable an amplifier, its control pin requires a negative bias of -1.5 to -2.0 Volts. Thermal Layout Considerations The device package for the ARA1400 features a heat slug on the bottom of the package body. Use of the heat slug is an integral part of the device design. Soldering it to the ground plane of the PC board will ensure the lowest possible thermal resistance for the device, and will result in the longest MTF (mean time to failure.) Output Switch Control A switch located at the output of Amplifier A2 in the ARA1400 provides isolation without having to disable the amplifiers. The switch is controled by the Tx logic input (pin 25). A PC board layout that optimizes the benefits of the heat slug is shown in Figure 5. The via holes located under the body of the device must be plated through to a ground plane layer of metal, in order to provide sufficient thermal conductivity. The recommended solder mask outline is shown in Figure 6. Amplifier Bias Current The ISET pins (11 and 27) set the bias current for the amplification stages. Grounding these pins results in the maximum possible current. By placing a resistor from the pin to ground, the current can be reduced. The recommended bias conditions use the configuration shown in the test circuit schematic in Figure 4. 0.025 BSC ESD Sensitivity Electrostatic discharges can cause permanent damage to these devices. Electrostatic charges accumulate on test equipment and the human body, and can discharge without detection. Proper precautions and handling are strongly recommended. Refer to the ANADIGICS application note on ESD precautions. 0.089 0.014 TYP BODY OUTLINE (NOMINAL) 0.025 MIN. 0.163 0.099 0.070 0.197 0.060 TYP. 0.400 Figure 5: PC Board Layout 8 Data Sheet - Rev 2.1 03/2004 0.150 (12X)0.020 TO 0.060 DIA.P PLATED THRU HOLES. DIMENSIONS IN INCHES ARA1400 0.016 TYP. 0.091 0.0535 0.025 TYP. 0.163 0.242 0.085 0.098 0.025 BSC 0.145 DIMENSIONS IN INCHES Figure 6: Solder Mask Outline Data Sheet - Rev 2.1 03/2004 9 ARA1400 PACKAGE OUTLINE Figure 7: S12 Package Outline - 28 Pin SSOP with Heat Slug 10 Data Sheet - Rev 2.1 03/2004 ARA1400 COMPONENT PACKAGING Volume quantities of the ARA1400 are supplied on tape and reel. Each reel holds 3,500 pieces. Smaller quantities are available in plastic tubes of 50 pieces. Figure 8: Reel Dimensions Figure 9: Tape Dimensions Data Sheet - Rev 2.1 03/2004 11 ARA1400 ORDERING INFORMATION ORDER NUMBER TEMPERATURE RANGE PACKAGE DESCRIPTION ARA1400S12CTR 0 to 85 °C 28 Pin SSOP with Heat Slug 3,500 piece tape and reel ARA1400S12C 0 to 85 °C 28 Pin SSOP with Heat Slug Plastic tubes (50 pieces per tube) COMPONENT PACKAGING 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 product’s 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. 12 Data Sheet - Rev 2.1 03/2004