Low Distortion IF Amplifier/ADC Driver with Digitally Controlled Gain

The LT5524 is a programmable gain amplifier (PGA) with bandwidth extending from low frequency (LF) to 540MHz. It consists of a digitally controlled variable attenuator, followed by a high linearity amplifier. 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 LT5524’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 LT5524 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.

Applications

* High Linearity ADC Driver

* IF Sampling Receivers

* VGA IF Power Amplifier

* 50Ω Driver

* Instrumentation Applications

* Output IP3 at 100MHz: 40dBm

* Maximum Output Power: 16dBm

* Bandwidth: LF to 540MHz

* Propagation Delay: 0.8ns

* Maximum Gain: 27dB

* Gain Control Range: 22.5dB

* Gain Control Step: 1.5dB

* Gain Control Settling Time: 500ns

* Noise Figure: 8.6dB at 100MHz (Max Gain)

* Output Noise Floor: –138dBm/Hz (Max Gain)

* Reverse Isolation: –92dB

* Single Supply: 4.75V to 5.25V

* Shutdown Mode

* Enable/Disable Time: 1µs

* Differential I/O Interface

* 20-Lead TSSOP Package