Broadband Variable-Gain Amplifiers

Transcription

1 1-; Rev 1; / EVALUATION KIT AVAILABLE Broadband Variable-Gain Amplifiers General Description The broadband RF variable-gain amplifiers (VGA) are designed for digital and OpenCable set-tops and televisions. These devices feature a unique design that integrates a dual-band (UHF and VHF) input and a low-noise, variable-gain amplifier. The integrated RF VGA covers a MHz to 1GHz input frequency range and provides db of gain-control range. The MAX is intended for the most difficult signal conditions where performance is critical. The external pullup inductor improves IIP and IIP while also increasing gain for better sensitivity. The MAX does not need an external pullup inductor and is ideal for low-power applications with less demanding receiver distortion requirements such as smaller TVs using indoor antennas. The are specified for operation in the C to + C temperature range and are available in mm x mm, 1-pin thin QFN packages with exposed paddle (EP). Applications OpenCable Set-Top Boxes and Televisions Digital Set-Top Boxes Media Gateways Digital Terrestrial Receivers TV IF Strips OpenCable is a trademark of Cable Television Laboratories, Inc. Features Low-Noise VGA Eliminates PIN Attenuator db Gain-Control Range Low Noise Figure: db at Maximum Gain Setting High Linearity: +1dBm IIP (MAX) at Maximum Gain Setting Low Power Consumption: <mw (MAX) Available in a mm x mm, 1-Pin Thin QFN Package PART Ordering Information TEMP RANGE PIN-PACKAGE PKG CODE MAXUTC C to + C 1 Thin QFN-EP* T1- MAXUTC+ C to + C 1 Thin QFN-EP* T1- MAXUTC C to + C 1 Thin QFN-EP* T1- MAXUTC+ C to + C 1 Thin QFN-EP* T1- *EP = Exposed paddle. +Denotes lead-free package. Pin Configuration/ Functional Diagram VHF_IN RF_GND GND 1 11 UHF_IN 1 LNAOUT RF_GND1 MAX/ V CC UHF_SHUNT RFAGC RBIAS SEL_UHF SHDN Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1---, or visit Maxim s website at

2 ABSOLUTE MAXIMUM RATINGS V CC to GND...-.V to +.V RFAGC, UHF_IN, SEL_UHF, VHF_IN, SHDN, RBIAS, RF_GND1, RF_GND, UHF_SHUNT to GND...-.V to (V CC +.V) LNAOUT Short-Circuit Duration...s UHFIN, VHFIN Maximum RF Input Power...1dBm CAUTION! ESD SENSITIVE DEVICE Continuous Power Dissipation (T A = + C) 1-Pin Thin QFN (derate 1.mW/ C above + C)...1mW Operating Temperature Range... C to + C Junction Temperature...+1 C Storage Temperature Range...- C to +1 C Lead Temperature (soldering, s)...+ C Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. DC ELECTRICAL CHARACTERISTICS ( EV kit, V CC =.V to.v, no RF signal applied, T A = C to + C, unless otherwise noted. Typical values are at V CC = V, R BIAS = 11.kΩ (MAX) or.1kω (MAX), T A = + C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS Supply Voltage.. V MAX. Operational mode ma Supply Current MAX Standby mode (V ENABLE = V SEL_UHF =.1V) µa RFAGC Input Bias Current V RFAGC = 1V and V - + µa RFAGC Control Voltage (Note ) Input Logic-Level Low Maximum gain Minimum gain 1. x V CC V V Input Logic-Level High. x V CC V AC ELECTRICAL CHARACTERISTICS (MAX) (MAX EV kit, V CC =.V to.v, T A = C to + C, unless otherwise noted. Typical values are at V CC = V, R BIAS = 11.kΩ, T A = + C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS Operating Frequency Range MHz Input Return Loss Diplex filter included, worst case across band, any gain setting (Note ).. db Input Power Range Per Channel - + dbmv Voltage Gain Maximum gain.. 1. db Linear Gain-Control Range Measured at MHz, difference between maximum and minimum gain 1..1 db Gain Flatness From MHz to MHz, V RFAGC = V (Note ). db Noise Figure Maximum gain, diplexer loss included db Input nd-order Intercept Point Maximum gain, V RFAGC = V (Notes, ) 1. Minimum gain, V RFAGC = 1V. dbm

3 AC ELECTRICAL CHARACTERISTICS (MAX) (continued) (MAX EV kit, V CC =.V to.v, T A = C to + C, unless otherwise noted. Typical values are at V CC = V, R BIAS = 11.kΩ, T A = + C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS Input rd-order Intercept Point Maximum gain, V RFAGC = V (Note ) 1. 1 Minimum gain, V RFAGC = 1V (Note ). 1dB Compression Point Maximum gain (Note ) 1. dbm Isolation Shutdown mode, MHz to MHz, RF input to RF output Port to port Output Return Loss Unbalanced Ω load db AC ELECTRICAL CHARACTERISTICS (MAX) (MAX EV kit, V CC =.V to.v, T A = C to + C, unless otherwise noted. Typical values are at V CC = V, R BIAS =.1kΩ, T A = + C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS Operating Frequency Range MHz Input Return Loss Diplex filter included, worst case across band, any gain setting (Note ) dbm dbc.. db Input Power Range Per Channel - + dbmv Voltage Gain Maximum gain db Linear Gain-Control Range Measured at MHz, difference between maximum and minimum gain 1 db Gain Flatness From MHz to MHz, V RFAGC = V (Note ). db Noise Figure Maximum gain, diplexer loss included db Input nd-order Intercept Point Input rd-order Intercept Point Maximum gain, V RFAGC = V (Notes, ) Minimum gain, V RFAGC = 1V. Maximum gain, V RFAGC = V (Note ) 1. 1 Minimum gain, V RFAGC = 1V (Note ) 1dB Compression Point Maximum gain. (Note ). dbm Isolation Shutdown mode, MHz to MHz, RF input to RF output 1 Port to port Output Return Loss Unbalanced Ω load db dbm dbm dbc Note 1: Guaranteed by production test at T A = + C and + C and does not include diplex filter loss, unless otherwise noted. Note : Guaranteed by design and characterization from T A = C to + C. Note : Tested with input tones at MHz and MHz at -1dBm/tone. Diplexer is not included. Note : Tested with input tones at MHz and MHz at -1dBm/tone. Diplexer is not included.

4 Typical Operating Characteristics (MAX EV kit with diplex filter removed, V CC = V, V RFAGC = V, T A = + C, unless otherwise noted.) SUPPLY CURRENT (ma) SUPPLY CURRENT vs. SUPPLY VOLTAGE T A = C T A = + C T A = + C SUPPLY VOLTAGE (V) MAX toc MAX GAIN vs. FREQUENCY T A = C T A = + C T A = + C 1 MAX toc GAIN vs. GAIN-CONTROL VOLTAGE f RF = MHz f RF = MHz MAX toc NOISE FIGURE (db) 1 11 NOISE FIGURE vs. FREQUENCY T A = + C T A = + C 1 T A = C MAX toc NOISE FIGURE (db) 1 NOISE FIGURE vs. GAIN f RF = MHz f RF = MHz MAX toc IIP (dbm) IIP vs. GAIN-CONTROL VOLTAGE f 1 = MHz f = MHz MAX toc IIP (dbm) 1 f 1 = MHz f = MHz IIP vs. V RFAGC MAX toc INPUT RETURN LOSS (db) INPUT RETURN LOSS vs. FREQUENCY 1 A: T A = + C, UHF_IN ENABLED B: T A = + C, UHF_IN ENABLED C: T A = C, UHF_IN ENABLED D E B A F C MAX toc D: T A = + C, VHF_IN ENABLED E: T A = + C, VHF_IN ENABLED F: T A = C, VHF_IN ENABLED OUTPUT RETURN LOSS (db) OUTPUT RETURN LOSS vs. FREQUENCY F E D 1 A: T A = + C, UHF_IN ENABLED B: T A = + C, UHF_IN ENABLED C: T A = C, UHF_IN ENABLED A B C MAX toc D: T A = + C, VHF_IN ENABLED E: T A = + C, VHF_IN ENABLED F: T A = C, VHF_IN ENABLED

5 Typical Operating Characteristics (continued) (MAX EV kit with diplex filter removed, V CC = V, V RFAGC = V, T A = + C, unless otherwise noted.) SUPPLY CURRENT (ma) 1 1 SUPPLY CURRENT AND IIP vs. R BIAS CURRENT f 1 = MHz f = MHz P IN = -1dBm/tone R BIAS (kω) IIP MAX toc IIP (dbm) MAX f RF = MHz GAIN vs. R BIAS R BIAS (kω) MAX toc SHUTDOWN ISOLATION vs. FREQUENCY 1 MAX toc1 Typical Operating Characteristics (MAX EV kit with diplex filter removed, V CC = V, V RFAGC = V, T A = + C, unless otherwise noted.) MAX SUPPLY CURRENT (ma) SUPPLY CURRENT vs. SUPPLY VOLTAGE T A = C T A = + C T A = + C MAX toc GAIN vs. FREQUENCY T A = + C T A = + C T A = C MAX toc GAIN vs. GAIN-CONTROL VOLTAGE f RF = MHz f RF = MHz MAX toc SUPPLY VOLTAGE (V)

6 IIP (dbm) NOISE FIGURE (db) Typical Operating Characteristics (continued) (MAX EV kit with diplex filter removed, V CC = V, V RFAGC = V, T A = + C, unless otherwise noted.) MAX NOISE FIGURE vs. FREQUENCY T A = + C T A = C T A = + C 1 f 1 = MHz f = MHz IIP vs. V RFAGC MAX toc MAX toc NOISE FIGURE (db) INPUT RETURN LOSS (db) 1 f RF = MHz NOISE FIGURE vs. GAIN f RF = MHz INPUT RETURN LOSS vs. FREQUENCY 1 A: T A = + C, UHF_IN ENABLED B: T A = + C, UHF_IN ENABLED C: T A = C, UHF_IN ENABLED A, B, C F E D MAX toc MAX toc IIP (dbm) OUTPUT RETURN LOSS (db) D: T A = + C, VHF_IN ENABLED E: T A = + C, VHF_IN ENABLED F: T A = C, VHF_IN ENABLED f 1 = MHz f = MHz IIP vs. V RFAGC OUTPUT RETURN LOSS vs. FREQUENCY A, B, C 1 A: T A = + C, UHF_IN ENABLED B: T A = + C, UHF_IN ENABLED C: T A = C, UHF_IN ENABLED E D F MAX toc MAX toc D: T A = + C, VHF_IN ENABLED E: T A = + C, VHF_IN ENABLED F: T A = C, VHF_IN ENABLED SUPPLY CURRENT (ma) SUPPLY CURRENT AND IIP vs. R BIAS CURRENT f 1 = MHz f = MHz P IN = -1dBm/tone R BIAS (kω) IIP MAX toc IIP (dbm) f RF = MHz GAIN vs. R BIAS R BIAS (kω) MAX toc SHUTDOWN ISOLATION vs. FREQUENCY 1 MAX toc1

7 PIN NAME FUNCTION 1 UHF_IN UHF Input. This input is terminated into Ω when not selected. RF_GND1 First RF Ground. Connect a pf capacitor from RF_GND1 to GND. Do not connect RF_GND1 to RF_GND. UHF_SHUNT UHF Shunt. Connects to GND when SEL_UHF is low, high impedance when SEL_UHF is high. RBIAS Amplifier Bias. Connect an 11.kΩ ±1% (MAX) or.1kω ±1% (MAX) resistor from RBIAS to GND. SEL_UHF Band - S el ect Inp ut. S el ects b etw een the U H F and V H F i np uts. Log i c l ow to sel ect V H F, l og i c hi g h to sel ect U H F. SHDN Shutdown. Logic low to put the device in standby mode. Logic high for normal operation. RFAGC Automatic Gain-Control Input. Accepts a DC voltage from 1V (minimum gain) to V (maximum gain). V C C S up p l y V ol tag e. Byp ass to G N D w i th p F and p F cap aci tor s p l aced as cl ose to the d evi ce as p ossi b l e. LNAOUT GND Ground 11 RF_GND RF Output. Requires a DC-blocking capacitor. The MAX requires a nh pullup inductor from LNAOUT to V CC. Second RF Ground. Connect a pf capacitor from RF_GND to GND. Do not connect RF_GND to RF_GND1. 1 VHF_IN VHF Input. This input is terminated into approximately Ω when not selected. EP GND Exposed Paddle. Solder evenly to the board s ground plane for proper operation. Pin Description Detailed Description The variable-gain amplifiers are designed for US digital television applications, specifically to meet ATSC s recommended receiver requirements. The MAX uses an external pullup inductor for maximum linearity and gain and is ideal for performance-driven applications. The MAX does not require an external pullup inductor and requires ma less current than the MAX. This results in slightly lower linearity and gain but is an acceptable option for cost- and/or power-sensitive applications. The two parts are otherwise identical and can use the same layout and application schematic except for the pullup inductor and RBIAS resistor. Dual-Band Inputs The feature two RF inputs, one for the VHF band (MHz to MHz) and one for the UHF band (MHz to MHz). An external diplex filter attenuates the undesired band. The diplex filter is easily implemented with discrete components, see the Typical Application Circuit for typical component values. Selection between the two inputs is achieved with a single digital input, SEL_UHF. See Table 1 for a description of SEL_UHF operation. The VHF and UHF inputs are terminated into approximately Ω when not selected. Table 1. SEL_UHF Operation SEL_UHF 1 FUNCTION Receive VHF channels (MHz to MHz) or cable channels below approximately MHz. Receive UHF channels (MHz to MHz) or cable channels above approximately MHz. Broadband Variable-Gain Amplifier (VGA) The integrate a broadband lownoise variable-gain amplifier. The MAX VGA has an open-collector output and requires a pullup inductor to V CC, while the MAX has an internal pullup to V CC. Both the MAX and MAX outputs require a DC-blocking capacitor. The provide a db gain-control range for increased system linearity. A DC voltage applied at the RFAGC pin controls the devices overall gain, and can range from 1V to V with V providing the maximum gain setting.

8 TYPICAL APPLICATION CIRCUIT FREQUENCY RESPONSE 1 A: MAX, VHF_IN ENABLED B: MAX, VHF_IN ENABLED A B C D C: MAX, UHF_IN ENABLED D: MAX, UHF_IN ENABLED NF (db) TYPICAL APPLICATION CIRCUIT NOISE FIGURE (MAX) VHF_IN ENABLED UHF_IN ENABLED 1 Figure 1. Frequency Response of the Typical Application Circuit NF (db) TYPICAL APPLICATION CIRCUIT NOISE FIGURE (MAX) VHF_IN ENABLED UHF_IN ENABLED 1 Figure. Noise Figure of MAX Typical Application Circuit Applications Information Terrestrial Television Applications Television receivers having dedicated RF inputs for cable and terrestrials reception can optimize the terrestrial path to better meet the difficult requirements recommended by ATSC. For dedicated terrestrial reception, the diplex filter is optimized for reception of VHF and UHF channels (MHz to MHz, and MHz to MHz). The diplex Figure. Noise Figure of MAX Typical Application Circuit filter attenuates the undesired channels, improving second-order distortion performance. Terrestrial + Cable Television Applications Television receivers having one RF input or multiple inputs that must receive cable and terrestrial channels must cover a MHz to MHz frequency range. The diplex filter must allow reception within this range while still providing attenuation of the undesired band. The Typical Application Circuit provides acceptable gain and noise figure performance over the diplexer transition band between VHF and UHF, see Figures 1 and. Layout Considerations The EV kit serves as a guide for PC board layout. Keep RF signal lines as short as possible to minimize losses and radiation. Use controlled impedance on all highfrequency traces. For proper operation, solder the exposed paddle evenly to the ground plane. Use abundant vias beneath the exposed paddle for maximum heat dissipation. Use abundant ground vias between RF traces to minimize undesired coupling. Bypass V CC to ground with nf and nf capacitors placed as close to the pin as possible, with the nf capacitor closest to the device. Chip Information TRANSISTOR COUNT: 1 PROCESS: BiCMOS

9 RFIN C11 pf C1.pF L1 nh L nh C.pF C pf C pf L.nH RF_GND1 UHF_SHUNT * MAX MAX R1 11.kΩ.1kΩ L OPEN nh L nh UHF_IN C1.pF 1 VHF_IN RBIAS 1 11 R1* RF_GND GND MAX/ SEL_UHF SHDN C pf Typical Application Circuit LNAOUT V CC RFAGC V CC ENABLE SEL_UHF C pf L* R kω C nf C pf INPUT C pf TV TUNER V RFAGC Figure. Typical Application Circuit

10 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to L QFN THIN.EPS PACKAGE OUTLINE, 1, 1,,, L THIN QFN, xx.mm D

11 Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to PACKAGE OUTLINE, 1, 1,,, L THIN QFN, xx.mm 1-1 D Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 1 San Gabriel Drive, Sunnyvale, CA Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.