Preliminary S518324-44Z UPSTREAM CATV AMPLIFIER FUNCTIONAL DIAGRAM FEATURES • SINGLE 3.3 V SUPPLY OPERATION • LOW POWER CONSUMPTION: 143 mA typical • 63 dB DYNAMIC RANGE: -2.5 to 61 dBmV output • EXCELLENT LINEARITY 2nd/3rd Harmonics >60 dBc typical • PROGRAMMABLE GAIN IN 0.5 dB STEPS • ULTRA LOW ON/OFF TRANSIENTS • DOCSIS 2.0 Plus and RoHS compliant DESCRIPTION The S518324 is a high performance, CMOS, low power programmable power amplifier designed for use in CATV upstream applications. The amplifier operates over a frequency range from 5 to 65 MHz and has a maximum output of 61 dBmV. A 3-wire serial interface controls the gain over a 63.5 dB range in 0.5 dB steps. The S518324 is available in a thermally enhanced QFN20 4x4 .The product is DOCSIS and RoHS compliant. APPLICATIONS • • • • Set-Top Boxes Cable Telephony Cable Modems CATV Infrastructure RF ELECTRICAL CHARACTERISTICS(TA = 25°C, VDD = 3.3 V, unless otherwise specified) SYMBOLS PARAMETERS UNITS MIN TYP dB dB dB dB dB dB dB dB 26 25.2 31 28 1.75 3.0 63.5 0.5 15 -90 MAX RF Performance AV AV HD2 HD3 Gain FIN = 5 MHz, Gain Code = 127 Gain FIN = 65 MHz, Gain Code = 127 Gain Flatness, FIN = 5 to 42 MHz Gain Flatness, FIN = 5 to 65 MHz Attenuation Range, Gain Code = 0 to 127 Attenuation Step Size, Gain Code = 0 to 127 Output Return Loss, 5 to 65 MHz Isolation, 5 to 65 MHz, TXEN = 0 (Transmit Disable Mode) Transmit Mode Noise, 5 to 65 MHz, BW = 160 KHz, Gain Code = 127 to 96 Transmit Mode Noise, 5 to 65 MHz, BW = 160 KHz, Gain Code = 95 to 32 Transmit Mode Noise, 5 to 65 MHz, BW = 160 KHz, Gain Code = 31 to 0 Transmit Disable Mode Noise, 5 to 65 MHz, BW = 160 KHz, TXEN = 0 2nd Harmonic Distortion, VOUT = 60 dBmV, 5 to 65 MHz 3rd Harmonic Distortion, VOUT = 60 dBmV, 5 to 65 MHz 2 3.5 10 dBmV -30 -28 dBmV -45 -43 dBmV -52 -50 dBmV -68 dBc dBc 60 58 Performance tests and ratings for RFMDs’ products were performed internally by RFMD and measured using specific computer systems and/or components and reflect the approximate performance of the products as measured by those tests. Any difference in circuit implementation, test software, or test equipment may affect actual performance. The information provided herein is believed to be reliable at press time and RFMDs assumes no responsibility for the use of this information. All such use shall be entirely at the user’s own risk. Prices and specifications for RFMDs’ products are subject to change without notice. Buyers should consult RFMDs’ standard terms and conditions of sale for RFMD’s limited warranty with regard to its products. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. RFMDs does not authorize or warrant any product for use in life-support devices and/or systems. 7628 Thorndike Road, Greensboro, NC 27409-9421 For sales or technical support, contact RFMD at (+1) 336-678-5570 or [email protected] 1 REV.9 6/19/2008 EDS-105590 Preliminary S518324-44Z DC ELECTRICAL CHARACTERISTICS SYMBOLS PARAMETERS UNITS MIN TYP MAX V mA mA mA uA 3.2 3.3 143 70 30 3.5 160 V V VDD -0.4 DC Performance VDD IDD Supply Voltage Supply Current Gain Code = 127 TXEN =1, D7 = 0,SLEEP = 1 Gain Code = 63 to 0 IDD Supply Current, TXEN = 0, D7 = 0, SLEEP = 1 IDD Supply Current, D7 =1 or SLEEP=0 Logic Inputs VINH Input High Voltage VINL Input Low Voltage ABSOLUTE MAXIMUM RATINGS 10 0.4 PIN ASSIGNMENTS (TC = 25°C unless otherwise noted) SYMBOLS PARAMETERS UNITS RATINGS VDD Supply Voltage V -0.3 to +3.6 TOP Operating Temperature °C -40 to +85 TSTG Storage Temperature °C -65 to 150 Tjmax Junction Temperature °C 150 ojc Thermal Resistance °C/W 34 Note: 1. Operation in excess of any one of these parameters may result in permanent damage. PIN FUNCTIONS QFN 20 PIN NAME D ESC RIPTION 1 GND Ground 2 GND Ground 3 VIN+ Posi ti ve i nput. 4 VIN- Negati ve i nput. 5 GND 6 LE 7 D ATA Seri al Interface D ata. TTL compati ble i nput. See Seri al Interface secti on 8 C LK Seri al Interface C lock. TTL compati ble i nput. See Seri al Interface secti on Ground 9 GND 10 S LE E P 11 NC 12 TERM Ground Seri al Interface Enable. TTL compati ble i nput. See Seri al Interface secti on. Hardware Shutdown. For fast shutdown, TXEN must be low when SLEEP i s set low. No C onnect A resi stor of 60ohms and a bypass cap must be connected i n seri es to the output of the transformer to ensure proper output i mpedance when output-amp i s di sable. 13 VOUT- Negati ve output of the output-amp stage. Along wi th VOUT+, the two ports form a di fferenti al i mpedance of 75 ohms. 14 VOUT+ Posi ti ve output of the output-amp stage. Along wi th VOUT-, the two ports form a di fferenti al i mpedance of 75 ohms. 15 RAMP An external capaci tor to ground i s connected to control the ramp-up and ramp-down duri ng transmi t enable and di sable. 16 TXEN 17 VC C 3.3V Transmi t enable. D ri ve TXEN hi gh to turn on the output stage. 18 GND Ground 19 GND Ground 20 VC C 3.3V 7628 Thorndike Road, Greensboro, NC 27409-9421 For sales or technical support, contact RFMD at (+1) 336-678-5570 or [email protected] 2 REV.9 6/19/2008 EDS-105590 Preliminary TYPICAL PERFORMANCE CURVES S518324-44Z TRANSMIT NOISE vs. GAIN CODE Output Noise (dBmV in 160 KHz) VOLTAGE GAIN vs. GAIN CODE 40 Voltage Gain (dB) 30 20 10 0 -10 -20 7MHz -30 43MHz -40 -25 -30 -35 -40 -45 -50 7MHz -55 43MHz -60 0 20 40 60 80 100 120 0 20 40 80 100 120 Gain Code Gain Code 2ND HARMONIC vs. GAIN CODE (POUT=60dBmV @ GCW=127) 3RD HARMONIC vs. GAIN CODE (POUT = 60dBmV @ GCW = 127) -40 -40 -45 -45 -50 -50 -60 -65 -70 -75 -80 ) -55 -55 ( 3rd Harmonic (dBc) 2nd Harmonic (dBc) 60 -60 -65 -70 -75 -80 7MHz -85 43MHz -90 7MHz -85 43MHz -90 50 60 70 80 90 100 110 120 50 Gain Code 60 70 80 90 100 110 120 Gain Code SUPPLY CURRENT vs. GAIN CODE 150 Supply Current (mA) 140 130 120 110 100 90 80 70 60 50 0 20 40 60 80 100 120 Gain Code 7628 Thorndike Road, Greensboro, NC 27409-9421 For sales or technical support, contact RFMD at (+1) 336-678-5570 or [email protected] 3 REV.9 6/19/2008 EDS-105590 Preliminary S518324-44Z FUNCTIONAL DESCRIPTION Upstream CATV Amplifier The upstream CATV amplifier consists of an input attenuator (ATTN1), pre-amp, intermediate attenuator (ATTN2), power amp, serial data interface, bias control, ramp generator, and a switch. The amplifier and the attenuator blocks are capable of providing a gain range of 63.5 dB with 0.5 dB steps across the specified frequencies of operation. The gain and current of the whole chain is determined by a 7 bit word programmed using the serial data interface. Input Interface The differential input impedance of the upstream CATV amplifier is 150 ohms. The input anti-aliasing filter should be designed to the same impedance for proper operation. The output impedance of the DAC should also be set accordingly. In order to achieve the specified performance, the inputs should be driven differentially. Output Interface The differential output impedance of the upstream CATV amplifier is 75 ohms provided that the suggested value of the shunt feedback resistor of the power amp stage is used. The differential output is converted to a single-ended output with a 1:1 turn ratio transformer. Switch During transmit disable mode, the 75 ohm output impedance is maintained by switching in a shunt 60 ohm resistor connected from the single-ended output of the transformer to Pin 12. The switch is toggled by the TXen pin, SLEEP pin, and D7 bit. When TXEN and SLEEP are high and D7 = 0 (transmit mode), the switch is open. It is closed when TXEN or SLEEP is low or D7 = 1. Power Amp (PA) The power amplifier stage is a Class A differential amplifier with shunt feedback and series feedback. It is capable of providing an output level of 61 dBmV. The 3.3 V bias of the PA stage comes from the center-tap of the 1:1 turn ratio transformer. The transformer will suppress the even-order distortion and the transients caused by enabling and disabling the PA. Ramp Generator This block is a simple RC charging circuit consisting of an internal 1K ohm resistor and an external capacitor Cext. This circuit controls the ramp up and down time of the PA stage during bursts. Bias Control The bias control sets the current of the PA stage at various gain states. In the lower gain states, the current of the PA is reduced and overall power consumption decreases. Serial Interface The serial interface becomes active when LE (latch enable) is low. The overall gain, current, and chip shutdown are determined by the programming of the bits D0 - D7. See Table 1, Table 2, Table 3, and Serial-Interface Timing Diagram for programming details. For fast shutdown, TXEN must be low when D7 is set low. 7628 Thorndike Road, Greensboro, NC 27409-9421 For sales or technical support, contact RFMD at (+1) 336-678-5570 or [email protected] 4 REV.9 6/19/2008 EDS-105590 Preliminary S518324-44Z FUNCTIONAL DESCRIPTION (CON'T) Table 1. Attenuator States TXen SLEEP D7 D6 D5 D4 D3 D2 D1 D0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 X 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 X X 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 X X X 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 X X X 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 0 X X X 1 1 1 0 0 1 1 1 0 1 1 0 0 1 1 1 0 0 X X X 1 1 1 0 0 1 1 0 0 1 1 1 0 1 1 0 0 0 X X X 1 1 0 1 0 1 1 0 0 1 1 0 0 1 1 1 0 0 X X X 1 0 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 0 X X X 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 Gain Code (Decimal) X X X 127 125 121 101 97 95 93 81 65 63 61 41 33 31 29 21 1 0 State Shutdown Transmit Disable Shutdown Av = 30.0 dB Av = 29.0 dB Av = 27.0 dB Av = 17.0 dB Av = 15.0 dB Av = 14.0 dB Av = 13.0 dB Av = 7.0 dB Av = -1.0 dB Av = -2.0 dB Av = -3.0 dB Av = -13.0 dB Av = -17.0 dB Av = -18.0 dB Av = -19.0 dB Av = -23.0 dB Av = -33.0 dB Av = -33.5 dB Table 3. Serial-Interface Control Word Table 2. Attenuator Values BIT ATTENUATION (dB) BIT MNEMONIC D0 0.5 MSB 7 D7 Shutdown (TXEN = 0) DESCRIPTION D1 1.0 6 D6 Gain Control, Bit 6 D2 2.0 5 D5 Gain Control, Bit 5 D3 4.0 4 D4 Gain Control, Bit 4 D4 8.0 3 D3 Gain Control, Bit 3 D5 16.0 2 D2 Gain Control, Bit 2 D6 32.0 1 D1 Gain Control, Bit 1 LSB 0 D0 Gain Control, Bit 0 Serial-Interface Timing Diagram A G B C D E F LE CLK DATA D7 D6 D5 A. t SENS B. t SDAS C. t SDAH D. t SCKL D4 D3 D2 D1 D0 E. t SCKH F. t SENH G. t DATAH /t DATAL 7628 Thorndike Road, Greensboro, NC 27409-9421 For sales or technical support, contact RFMD at (+1) 336-678-5570 or [email protected] 5 REV.9 6/19/2008 EDS-105590 Preliminary TYPICAL APPLICATION CIRCUIT S518324-44Z PACKAGE INFORMATION QFN 20 (Units in mm) 7628 Thorndike Road, Greensboro, NC 27409-9421 For sales or technical support, contact RFMD at (+1) 336-678-5570 or [email protected] 6 REV.9 6/19/2008 EDS-105590 Preliminary S518324-44Z TX_EN Evaluation Board Schematic C21 .01uF GND 3.3V 3.3V R4 1k C20 .01uF C14 1000pF R14 0 GND GND GND 3 3 GND TOKO Footprint GND C5 .01uF TX_LE DA CK TX_SH TX_EN 17 16 TXEN VCC 18 GND 19 TERM GND NC R3 75 GND C13 NL C11 C9 C16 R17 NL 1k R18 0 3 C17 NL 5 R19 1k 6 .01uF R22 NL J1 GND 1 2 GND 3 -4.77dB R11 43 GND R2 0 R20 0 R21 1k 4 C15 1000pF GND 4 TOKO 1:1 R6 .01uF 43 R7 43 GND R15 0 1 2 3 12 11 GND C18 NL GND 7 7PIN DA 3.3V .01uF GND TX_LE GND TXin- R16 0 JP2 GND GND TX_SH 1 TOKO 1:1 GND 13 Vout- 6 6 6 3.3V 4 5 GND TXin+ SLEEP 2 T1 C10 GND R13 NL GND -4.77dB 4 R8 75 9 R12 NL 1 14 Vout+ 10 GND GND 1000pF 2 CK 1 GND CLK 2 T1 2 C4 GND .01uF SDATA 24 C2 2.2pF 8 GND C12 .01uF C1 15 RAMP U1 S518324-44Z DATEN R9 3 GND 7 J3 1 GND GND GND VCC 20 GND GND PACKAGE INFORMATION (CON'T) 1. 2. 3. Dimensions and tolerances conform to ASME Y14.5-1994. All dimensions are in millimeters. All angles are in degrees. The exposed thermal pad is also an electrical ground . LAND PATTERN FOR TERMINALS AND THERMAL/GROUND PAD DATA SUBJECT TO CHANGE WITHOUT NOTICE 7628 Thorndike Road, Greensboro, NC 27409-9421 For sales or technical support, contact RFMD at (+1) 336-678-5570 or [email protected] 7 REV.9 6/19/2008 EDS-105590