LT5514 - Ultralow Distortion IF Amplifier/ADC Driver with Digitally Controlled Gain

The LT5514 is a programmable gain amplifier (PGA) with bandwidth extending from low frequency (LF) to 850MHz. It consists of a digitally controlled variable attenuator, followed by a high linearity amplifier. The amplifier is configured with two identical transconductance amplifiers, hard wired in parallel with individual dedicated enable pins. When both amplifiers are enabled (Standard mode), the LT5514 offers an OIP3 of +47dBm (at 100MHz). Power dissipation can be reduced when a single amplifier is enabled (Low Power mode). Four parallel digital inputs control the gain over a 22.5dB range with 1.5dB step resolution. An on-chip power supply regulator/filter helps isolate the amplifier signal path from external noise sources.

The LT5514’s open-loop architecture offers stable operation for any practical load conditions, including peaking-free AC response when driving capacitive loads, and excellent reverse isolation.

The LT5514 may be operated broadband, where the output differential RC time constant sets the bandwidth, or it may be used as a narrowband driver with the appropriate output filter.

  • Output IP3 at 100MHz: 47dBm
  • Maximum Output Power: 21dBm
  • Bandwidth: LF to 850MHz
  • Propagation Delay: 0.8ns
  • Maximum Gain: 33dB
  • Noise Figure: 7.3dB (Max Gain)
  • Gain Control Range: 22.5dB
  • Gain Control Step: 1.5dB
  • Gain Control Settling Time: 500ns
  • Output Noise Floor: –134dBm/Hz (Max Gain)
  • Reverse Isolation: –80dB
  • Single Supply: 4.75V to 5.25V
  • Low Power Mode
  • Shutdown Mode
  • Enable/Disable Time: 1µs
  • Differential I/O Interface
  • 20-Lead TSSOP Package
Typical Application
LT5514 Typical Application
LT5514 Typical Application
  • High Linearity ADC Driver
  • IF Sampling Receivers
  • VGA IF Power Amplifier
  • 50 Ohm Driver
  • Instrumentation Applications
LT5514 Package Drawing
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
Demo Boards
Part NumberDescriptionPrice
DC550ALT5514EFE | High Linearity Variable Gain IF Amp / ADC Driver$150.00
Application Note
Reliability Data
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LT5514 Footprints and Symbols