آر اف (فرکانس رادیویی) و بی‌سیم سایر آی سی‌ و ماژول‌های آر اف

Product Attributes

Introduction

The AD9874 is a general-purpose IF subsystem that digitizes a low level 10 MHz–300 MHz IF input with a signal bandwidth ranging from 6.8 kHz to 270 kHz. The signal chain of the AD9874 consists of a low noise amplifier, a mixer, a band-pass sigma-delta analog-to-digital converter, and a decimation filter with programmable decimation factor. An automatic gain control (AGC) circuit gives the AD9874 12 dB of continuous gain adjustment. Auxiliary blocks include both clock and LO synthesizers. The AD9874’s high dynamic range and inherent antialiasing provided by the band-pass sigma-delta converter allow the AD9874 to cope with blocking signals up to 95 dB stronger than the desired signal. This attribute can often reduce the cost of a radio by reducing its IF filtering requirements. Also, it enables multimode radios of varying channel bandwidths, allowing the IF filter to be specified for the largest channel bandwidth. The SPI port programs numerous parameters of the AD9874, thus allowing the device to be optimized for any given application. Programmable parameters include the following: synthesizer divide ratios; AGC attenuation and attack/decay time; the received signal strength level; decimation factor; the output data format; 16 dB attenuator; and the selected bias currents. The bias currents of the LNA and mixer can be further reduced at the expense of the degraded performance for batterypowered applications.

Features

• 2.7 V–3.6 V Supply Voltage
• Low Current Consumption: 20 mA
• 48–Lead LQFP Package (1.4 mm Thick)

Applications

• Multimode Narrowband Radio Products
• Analog/Digital UHF/VHF FDMA Receivers
• TETRA, APCO25, GSM/EDGE
• Portable and Mobile Radio Products
• Base Station Applications