LT5554 - Broadband Ultra Low Distortion 7-Bit Digitally Controlled VGA

Features

  • 1GHz Bandwidth at all Gains
  • 48dBm OIP3 at 200MHz, 2VP-P into 50Ω, ROUT = 100Ω
  • –88dBc IMD3 at 200MHz, 2VP-P into 50Ω, ROUT = 100Ω
  • 1.4nV/√Hz Input-Referred-Noise (RTI)
  • 20dBm Output P1dB at 70MHz, ROUT = 130Ω
  • 2dB to 18dB Gain Range (ROUT = 50Ω)
  • 0.125dB Gain Step Size
  • 30ps Group Delay Variation
  • 5ns Fast Gain Settling Time
  • 5ns Fast Overdrive Recovery
  • –80dB Reverse Isolation

Typical Application

LT5554 Typical Application
LT5554 Typical Application

Description

The LT5554 is a 7-bit digitally controlled programmable gain (PG) amplifier with 16dB gain control range. It consists of a 50Ω input variable attenuator, followed by a high linearity variable transconductance amplifier. The coarse 4dB input attenuator step is implemented via 2-bits of digital control (PG5, PG6). The fine transconductance amplifier 0.125dB step within 3.875dB gain control range is set via 5-bits digital control (PG0 to PG4). The LT5554 gain control inputs (PGx) and the STROBE input can be directly coupled to TTL or ECL drivers. The seven parallel gain control inputs time skew can be eliminated by using the STROBE input positive transition.

The internal output resistor RO = 400Ω limits the maximum overall gain to 36dB for open outputs. The internal circuitry of open output collectors enables the LT5554 to be unconditionally stable over any loading conditions (including external SAW filters) and provides –80dB reverse isolation at 300MHz.

The LT5554 is internally protected during overdrive and has an on-chip power supply regulator.

With 0.125dB step resolution and 5ns settling time, the LT5554 is suitable in applications where continuous gain control is required.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing
RoHS
LT5554IUH#PBF 5x5 QFN-32 UH I 05-08-1693 Yes
LT5554IUH#TRPBF 5x5 QFN-32 UH I 05-08-1693 Yes


LT5554 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LT5554IUH#PBF 5x5 QFN-32 I $6.29 $4.40 Yes
LT5554IUH#TRPBF 5x5 QFN-32 I $4.45 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC1150A LT5554 | Broadband Ultra-Low Distortion Digitally Programmable VGA $125.00
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Click here to view our complete list of demo boards

Applications

  • Differential ADC Driver
  • IF Sampling Receivers
  • VGA IF Power Amplifier
  • 50Ω Driver
  • Instrumentation

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Design Tools

Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:

  • LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
  • LTpowerCAD - A complete power supply selection, synthesis and design tool
  • LTpowerPlay - A development environment supporting Linear Technology's Digital Power System Management (PSM) products
  • PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
  • Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
  • LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
  • And More!

Technical Support