Linear Technology DC503A User manual

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DC503A DEMO BOARD QUICK START GUIDE
Description:
The DC503A demo circuit board is intended to demonstrate the capabilities of the LT5512
downconverting mixer IC for cable infrastructure applications.
The LT5512 (Figure 1) is a broadband high signal level mixer IC optimized for high linearity
downconverter applications including cable and wireless infrastructure. The IC includes a
differential LO buffer driving a double-balanced mixer. An integrated RF amplifier improves LO-
RF isolation and eliminates the need for precision external bias resistors.
The LT5512 is a high-linearity alternative to passive diode mixers. Unlike passive mixers, which
have conversion loss and require high LO drive level, the LT5512 delivers conversion gain and
requires significantly lower LO drive levels.
The DC503A demo board downconverts 1230MHz RF input to 270-870MHz IF output. The LO is
injected from the high-side between 1500MHz and 2100MHz.
Figure 1. LT5512 IC Block Diagram

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LT5512 Downconverting Mixer Single-Tone Measurements for 1230 MHz CATV Band.
1. Connect all test equipment as shown in Figure 2.
2. Set the Power Supply output voltage to 5V, and set the current limit to 100mA.
3. Connect TP1 (EN) to the 5V power supply. Mixer is in ENABLE mode.
4. Set the Signal Generator #1 to provide an 1800MHz, -10dBm, CW signal to the demo board
LOin port.
5. Set the Signal Generator #2 to provide a 1230MHz, -10dBm, CW signal to the demo board
RFin port.
6. Set the Spectrum Analyzer’s center frequency to 570MHz. Perform mixer conversion gain,
and 1dB compression measurements.
7. Set the Spectrum Analyzer’s center frequency to 1800MHz. Perform mixer LO to IF
leakage measurement.
SPECTRUM
ANALYZER
SIGNAL
GENERATOR 1
SIGNAL
GENERATOR 2
POWER SUPPLY
Figure 2. Test Set-Up for Mixer Single-Tone Measurements.

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LT5512 Downconverting Mixer Two-Tone Measurements for 1230MHz CATV Band.
1. Connect all test equipment as shown in Figure 3.
Note: 1). A high quality combiner that provides 50-ohm termination on all ports and has
good port-to-port isolation should be used.
2). The two 3dB attenuators on the inputs of the combiner are used to further
improve source isolation.
2. Set the Power Supply output voltage to 5V, and set the current limit to 100mA.
3. Connect TP1 (EN) to the 5V power supply. Mixer is in ENABLE mode.
4. Set the Signal Generator #1 to provide a 1800MHz, -10dBm, CW signal to the demo board
LOin port.
5. Set the Signal Generator #2 and #3 to provide two -10dBm CW signals to the demo board
RFin port—one at 1229.9MHz, and the other at 1230.1MHz.
6. Set the Spectrum Analyzer’s center frequency to 570MHz. Perform input 3rd order
distortion measurement. (IIP3 = P1 + (P1 – P3) / 2 – Gc, where P1 is the lowest power level
of the two desired output tones at either 569.9MHz or 570.1MHz, P3 is the largest 3rd order
product at either 569.7MHz or 570.3MHz, and Gc is conversion gain. P1 and P3 are in units
of dBm, and Gc is in dB.)
SPECTRUM
ANALYZER
SIGNAL
GENERATOR 1
SIGNAL
GENERATOR 2
POWER SUPPLY
Figure 3. Test Set-Up for Mixer Two-Tone Measurements.
SIGNAL
GENERATOR 3
∑
3dB PAD
3dB PAD

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APPROVED VENDOR LIST
VENDOR PHONE NUMBER PART TYPE WEBSITE ADDRESS
AAC (was TAD) [phone] CHIP RESISTORS
AAC (was TAD) [phone]
AAVID [phone] HEAT SINKS
ALLEN BRADLEY [phone] CARBON RESISTORS
AMP [phone] PC MOUNT BNC
APEM [phone] SMD TOGGLE/PB SWITCH
API DELEVAN [phone] INDUCTORS
AVX [phone] CHIP CAPS
AVX [phone] CHIP RESISTORS
AVX [phone] TANTALUM CAPS
AVX [phone] HIGH VOLTAGE CAPS
BERG [phone] CONNECTORS
BH ELECTRONICS [phone] INDUCTORS
BI TECHNOLOGIES [phone] TRANSFORMERS
BI TECHNOLOGIES [phone] RES./RES. NETWORKS
BOURNS [phone] POTENTIOMETERS, SIPS
CADDOCK ELECTRONICS [phone] HIPO. RES., SIPS, DIPS
CENTRAL SEMI [phone] SMALL SIGNAL DISCRETES
CHICAGO MINIAT. LAMP [phone] LEDS
COILCRAFT [phone] INDUCTORS
COMM CON [phone] HEADERS, SHUNTS
CONNEX [phone] BNC CONNECTORS
COOPER ELECT. TECH. [phone] INDUCTORS
CORNELL DUBILIER [phone] CAPACITORS
CTS [phone] RESISTOR ARRAYS
CUI-STACK [phone] POWER CONNECTORS
DALE (see Vishay) [phone] INDUCTORS
DALE (see Vishay) [phone] SENSE RESISTORS
DATA DISPLAY PRODUCT [phone] LEDS
DIODES INC. [phone] DIODES
ELECTRONIC CONCEPTS [phone] 400V FILM CAPACITORS
EPSON [phone] CRYSTALS
FAIRCHILD [phone] LOGIC
FAIRCHILD [phone] MOSFETS
FAIRCHILD [phone] CRG (CUST. RESPONSE)
FCI [phone] HOT PLUG CONNECTORS
FUKUSHIMA [phone] MPC RESISTORS
FUJI [phone] SCHOTTKY DIODES
GENERAL
SEMICONDUCTOR [phone] DIODES
GOWANDA [phone] INDUCTORS
GRAYHILL [phone] DIP SWITCHES
HARRIS [phone] LOGIC
HEWLETT PACKARD [phone] IR LED
HITACHI [phone] RF POWER AMPS

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IDT [phone] LOGIC IC
IR [phone] MOSFETS
IRC [phone] SENSE RESISTORS
ITW PAKTRON [phone] CAPACITORS
JOHNSON COMPONENTS [phone] RF CONNECTORS
JOHNSON COMPONENTS [phone] RF CONNECTORS
KEMET [phone] TANTALUM CAPS
KEMET [phone] CRG (CUST. RESPONSE)
KETEMA [phone] SURGE SUPPRESSORS
KEYSTONE [phone] JACKS, TURRETS
LITEON [phone] LEDS, DIODES
LTC [phone] HIGH PERF. I.C.S
MAGNETICS [phone] TOROID CORES ETC.
MARCON [phone] HIGH C/V CAPACITORS
METHODE [phone] ZIF SOCKETS
MF ELECTRONICS [phone] CRYSTAL OSCILLATORS
MICROCHIP [phone] MICROCONTROLLER IC
MICRO PLASTICS [phone] NYLON STANDOFFS
MICRO-SEMI [phone] DIODES
MIDCOM [phone] INDUCTORS
MIDCOM [phone] INDUCTORS
MILL-MAX [phone] TURRETS
MINICIRCUITS [phone] RF TRANSFORMERS
MOTOROLA [phone] LOGIC, REGS
MURATA ELECTRONICS [phone] CAPS., INDUCTORS,
MURATA ELECTRONICS [phone] CRG (CUST. RESPONSE)
MURATA ELECTRONICS [phone] RF DEVICES
NEC/TOKIN [phone] INDUCTORS/HI C/V CAPS
NICHIA [phone] WHITE LEDS
NICHICON [phone] ELECTROLYTIC CAPACITOR
ON SEMICONDUCTOR [phone] DISCRETE DIODES ETC.
ON SHORE [phone] TERMINATORS
PANASONIC [phone] INDUCTORS, POLY CAPS
PANASONIC [phone] LEDS
PANASONIC [phone] SWITCHES
PERICOM [phone] LOGIC IC
PHILIPS [phone] INDUCTORS
PHILIPS [phone] PLANAR INDUCTORS
PHILIPS [phone] DISCRETES, I.C.s
PULSE [phone] INDUCTORS
QT OPTOELECTRONICS [phone] RF SWITCH
RAYCHEM [phone] FUSES
RG ALLEN [phone] METAL OXIDE RESISTORS
RF MICRO DEVICES [phone] RF2138 / RF2140
SAMTEC [phone] WIRE JUMPERS
SANYO [phone] OSCON CAPS
SCHOTT [phone] INDUCTORS, XFORMERS
SCHURTER [phone] FUSES AND HOLDERS

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SIGNATRON [phone] DB9 CONNECTORS
SIEMENS [phone] OPTO
SILICONIX [phone] MOSFETS
SILICONIX [phone] MOSFETS
SPRAGUE [phone] CAPACITORS
SULLINS [phone] HEADERS, SHUNTS
SUMIDA [phone] INDUCTORS
SUMIDA [phone] INDUCTORS
TAIYO YUDEN [phone] CHIP CAPS / RES.
TAIYO YUDEN [phone] CRG (CUST. RESPONSE)
TEKTRONIX [phone] SCOPE PROBE SOCKETS
TEMIC [phone] IR PHOTO DIODE
THERMALLOY [phone] HEAT SINKS
THIN FILM TECHNOLOGY [phone] THIN FILM CHIP RESISTORS
TOCOS [phone] SMD POTENTIOMETERS
TOKIN (NEC) [phone] CAPS., INDUCTORS,
TOKO [phone] RF PRODUCTS
TOSHIBA [phone] SINGLE GATE LOGIC
TOSHIBA [phone] LOGIC
UNITED CHEMICON [phone] ELECTROLYTIC CAPACITOR
VISHAY [phone] ZENER/SM. SIGNAL DIODES
VISHAY [phone] INDUCTORS, SENSE Rs
VITRAMON [phone] CERAMIC CHIP CAPACITOR
WIMA [phone] PAPER/FILM CAPACITORS
ZETEX [phone] SMALL SIGNAL DISCRETES
ZIERICK [phone] STAKED PINS

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Mouser Electronics
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DC503A