S518324-44Z RFMD | Alldatasheet

Document overview

  • Manufacturer or author: pROVIDED bY alldatasheet.com(free datasheet download site)
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Technical content

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
  • Set-Top Boxes
  • Cable Telephony
  • Cable Modems
  • CATV Infrastructure

APPLICATIONS

DESCRIPTION

The S518324 is a high performance, CMOS, low power pro- grammable power amplifier designed for use in CATV up- stream 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. RF ELECTRICAL CHARACTERISTICS (TA = 25°C, V DD = 3.3 V, unless otherwise specified) SYMBOLS PARAMETERS UNITS MIN TYP MAX RF Performance AV Gain FIN = 5 MHz, Gain Code = 127 dB 26 31 AV Gain FIN = 65 MHz, Gain Code = 127 dB 25.2 28 Gain Flatness, FIN = 5 to 42 MHz dB 1.75 2 Gain Flatness, FIN = 5 to 65 MHz dB 3.0 3.5 Attenuation Range, Gain Code = 0 to 127 dB 63.5 Attenuation Step Size, Gain Code = 0 to 127 dB 0.5 Output Return Loss, 5 to 65 MHz dB 15 10 Isolation, 5 to 65 MHz, TXEN = 0 dB -90 (Transmit Disable Mode) Transmit Mode Noise, 5 to 65 MHz, BW = 160 KHz, dBmV -30 -28 Gain Code = 127 to 96 Transmit Mode Noise, 5 to 65 MHz, BW = 160 KHz, dBmV -45 -43 Gain Code = 95 to 32 Transmit Mode Noise, 5 to 65 MHz, BW = 160 KHz, dBmV -52 -50 Gain Code = 31 to 0 Transmit Disable Mode Noise, 5 to 65 MHz, dBmV -68 BW = 160 KHz, TXEN = 0 HD2 2 nd Harmonic Distortion, VOUT = 60 dBmV, 5 to 65 MHz dBc 60 HD3 3 rd Harmonic Distortion, VOUT = 60 dBmV, 5 to 65 MHz dBc 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 sales-support@rfmd.com REV.9 6/19/2008 EDS-105590 Preliminary

DC ELECTRICAL CHARACTERISTICS SYMBOLS PARAMETERS UNITS MIN TYP MAX DC Performance VDD Supply Voltage V 3.2 3.3 3.5 IDD Supply Current Gain Code = 127 mA 143 160 TXEN =1, D7 = 0,SLEEP = 1 Gain Code = 63 to 0 mA 70 I DD Supply Current, TXEN = 0, D7 = 0, SLEEP = 1 mA 30 IDD Supply Current, D7 =1 or SLEEP=0 uA 10 Logic Inputs VINH Input High Voltage V V DD -0.4 VINL Input Low Voltage V 0.4 S518324-44Z Note: 1. Operation in excess of any one of these parameters may result in permanent damage. ABSOLUTE MAXIMUM RATINGS (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 PIN ASSIGNMENTS PIN FUNCTIONS NFQ

02 EMANNIPN OITPIRCSED

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SUPPLY CURRENT vs. GAIN CODE TYPICAL PERFORMANCE CURVES S518324-44ZSupply Current (mA) Voltage Gain (dB) VOLTAGE GAIN vs. GAIN CODE support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com REV.9 6/19/2008 EDS-105590 Gain Code TRANSMIT NOISE vs. GAIN CODE Output Noise (dBmV in 160 KHz) Gain Code 3RD HARMONIC vs. GAIN CODE (POUT = 60dBmV @ GCW = 127) 3rd Harmonic (dBc) Gain Code Gain Code -40 -30 -20 -10 0 2 04 06 08 0 1 0 0 1 2 0 7MHz 43MHz -60 -55 -50 -45 -40 -35 -30 -25 0 2 04 06 08 0 1 0 0 1 2 0 7MHz 43MHz 100 110 120 130 140 150 0 20 40 60 80 100 120 Gain Code -90 -85 -80 -75 -70 -65 -60 -55 -50 -45 -40 50 60 70 80 90 100 110 120 7MHz 43MHz 2ND HARMONIC vs. GAIN CODE (POUT=60dBmV @ GCW=127) -90 -85 -80 -75 -70 -65 -60 -55 -50 -45 -40 50 60 70 80 90 100 110 120 2nd Harmonic (dBc) 7MHz 43MHz Preliminary

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 attenu- ator 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 deter- mined 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 imped- ance is maintained by switching in a shunt 60 ohm resis- tor connected from the single-ended output of the trans- former 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 dis- abling 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 de- termined 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. FUNCTIONAL DESCRIPTION support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com REV.9 6/19/2008 EDS-105590 Preliminary

Table 3. Serial-Interface Control Word

6 D6 Gain Control, Bit 6

5 D5 Gain Control, Bit 5

4 D4 Gain Control, Bit 4

3 D3 Gain Control, Bit 3

2 D2 Gain Control, Bit 2

1 D1 Gain Control, Bit 1

0 X 1 X X X X X X X X Shutdown

Table 1. Attenuator States Table 2. Attenuator Values

TYPICAL APPLICATION CIRCUIT S518324-44Z PACKAGE INFORMATION QFN 20 (Units in mm) support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com REV.9 6/19/2008 EDS-105590 Preliminary

  1. Dimensions and tolerances conform to ASME Y14.5-1994. 2. All dimensions are in millimeters. All angles are in degrees. 3. The exposed thermal pad is also an electrical ground . DATA SUBJECT TO CHANGE WITHOUT NOTICE PACKAGE INFORMATION (CON'T) LAND PATTERN FOR TERMINALS AND THERMAL/GROUND PAD

support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com REV.9 6/19/2008 EDS-105590 Evaluation Board Schematic GND GND GND GND GND 1000pF C4.01uF .01uF .01 uF C1 0 .01uF GND GND GND GND R41k 6T1 TOKO 1:1 TX_EN TX_SH C11 .01uF C12 .01 uF JP2 7PIN TX_L E DA CK TX_S H TX_E N GND GND TX_LE DA CK R875 GND GND TOK O Footpri nt GND1 TERM 12 GND 2 NC 11 TXin+3 SLEEP10 TXin-4 GND9 GND5 CLK8 DATEN6 SDATA7 Vout - 13 Vout+ 14 RAMP 15 TXEN 16 VCC 17 VCC 20 GND 18 GND 19 S518324-44Z 3.3V 3.3V 3.3V R11 GND GND1 -4.77dB GND GND 1 -4.77dB R12NL GND R13 NL C1 3 NL GND 3.3V R140 C141000pF GND C1 5 1000pF GND R1 5 R1 60 R1 7 R18 R19 R2 00 R2 1 C16 NL C17 NL C1 8NL GND GND GND R2 2 NL GND GND C20 .01 uFC2 1 .01uF GND GND TOKO 1:1 2.2pF GND Preliminary