Milpitas CA, — Linear Technology has introduced the LT5554, a broadband digitally programmable gain IF amplifier, featuring a 48 dBm OIP3 (output 3rd order intercept) at 200 MHz. Additionally, the amplifier has very low noise, enabling high dynamic range performance in wireless communication receivers and signal processing systems.
Its gain is digitally controlled from 2 dB to 18 dB by a 7-bit parallel word, claiming the finest 0.125 dB steps gain control granularity of any IF amplifier available on the market. The amplifier settles in less than 5 ns from a gain change, producing low glitch noise and supporting very fast and accurate AGC (Automatic Gain Control) performance. Its output stage has robust capability to drive into 50-Ω loads with low distortion and noise. Consequently, it enables high spurious-free dynamic range performance in ADC systems.
Unique to the LT5554 is its OIP3 performance, which remains consistently high over a wide varying signal level range. In contrast, the closest competing solution is limited to only a narrow ±1 dB signal level range. With today's new generation of wireless technology such as LTE (Long-Term Evolution) and WiMAX, which use modulated signals with 12 dB crest-factor, the need to maintain linearity performance over wide operating levels is paramount for producing consistent basestation performance.
Additionally the LT5554 has excellent gain accuracy of ±0.1 dB from -40 to 85 degrees Celsius, which is a five time improvement over the closest competing offering, which has accuracy of ±0.5 dB over similar temperature range.
The LT5554 is a full differential input and output amplifier. Its differential outputs can drive directly into 50 Ω loads. The amplifier may be overdriven and can recover very quickly in less than 5 ns. Additionally, the amplifier has excellent reverse isolation. These characteristics make it an ideal amplifier to drive high speed, high resolution A/D converters, where the input sampling noise can couple back to the RF and IF circuits.
The LT5554 is powered from a single 5 V supply. It draws a nominal supply current of 200 mA. The chip can be shutdown via an ENABLE pin. When in shutdown the device draws a typical supply current of 4 mA, and a maximum of 5.1 mA. The device comes in a 32-lead, 5-mm x 5-mm plastic QFN surface mount package.
A data sheet is available.
