• 简体中文
• English

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.

Features 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

Applications High Linearity ADC Driver IF Sampling Receivers VGA IF Power Amplifier 50 Ohm Driver Instrumentation Applications Packaging

Demo Boards