It's crucial for cellular basestation designers to get the most dynamic performance out of their components. A new option, the LT1750 14-bit analog-to-digital converter (ADC) from Linear Technology, samples at 80 Msamples/s while accepting input signals up to 500 MHz.
This ADC delivers a spurious-free dynamic range (SFDR) of −84 dB at 140 MHz. Even with a 350-MHz input, SFDR measures −74 dB. Its signal-to-noise ratio (SNR) is rated at −71.7 dB at a 140-MHz input as well. Selectable input ranges are available from 1.3 to 2.25 V p-p. The output ranges from 0.5 to 5 V.
An on-chip programmable-gain amplifier (PGA) permits the use of multiple input ranges that lower noise levels and make it easier to meet IP3 communications requirements. An overflow pin enables automatic indication of an input that exceeds the rated range. A separate digital-output supply pin makes it possible to connect to low-voltage DSPs, FIFOs, or logic as low as 0.5 V.
The LT1750 dissipates 1.45 W and operates from a single 5-V supply. It comes in a 48-pin TSSOP package and is rated for operation over the commercial and industrial temperature ranges. Pricing for the converter begins at $32.30 each in quantities of 1000 units.Linear Technology Corp. www.linear.com (408) 432-1900