AD6600 ADC IC Chip

AD6600(Dual Channel, Gain-Ranging ADC with RSSI)

Introduction

The AD6600 mixed-signal receiver chip directly samples signals at analog input frequencies up to 250 MHz. The device includes two input channels, each with 1 GHz input amplifiers and 30dB of automatic gain-ranging circuitry. Both channels are sampled with a 450 MHz track-and-hold followed by an 11-bit,20 MSPS analog-to-digital converter. Digital RSSI outputs, an AB channel indicator, a 2x Clock output, references, and control circuitry are all on-chip. Digital output signals are two’s complement, CMOS-compatible and interface directly to 3.3 V or 5 V digital processing chips.

The primary use for the dual analog input structure is sampling both antennas in a two-antenna diversity receiver.However, users may also use Channels A and B to sample two independent IF signals. Diversity, or dual channel mode, limits each channel to 10 MSPS. In single-channel mode, users can apply the full clock rate of 20 MSPS to a single carrier.

The AD6600 may be used as a stand-alone sampling chip, or it may be combined with the AD6620 Digital Receive Signal Processor. The AD6620 provides 10dB—25dB of additional processing gain before passing data to a fixed- or floating point DSP.

Driving the AD6600 is simplified by using the AD6630 differential IF amplifier. The AD6630 is easily matched to inexpensive SAW filters from 70MHz to 250MHz.

Designed specifically for cellular/PCS receivers, the AD6600 supports GSM, IS-136, CDMA and Wireless I ANs, as well as proprietary air interfaces used in WLI /fixed-access systems.

Units are available in plastic, surface-mount packages (44-lead LQFP) and specified over the industrial temperature range(-40°C to +85°C).

Feature

• Dual IF Inputs, 70 MHz- -250 MHz
• Diversity or Two Independent IF Signals
• Separate Attenuation Paths
• Oversample RF Channels
• 20 MSPS on a Single Carrier
• 10 MSPS/Channel in Diversity Mode
• Total Signal Range 90+ dB
• 30dB from Automatic Gain-Ranging (AGC)
• 60dB from A/D Converter
• Range >100dB After Processing Gain
• Digital Outputs
• 11-Bit ADC Word
• 3-Bit RSSI Word
• 2x Clock, A/B Indicator
• Single 5 V Power Supply
• Output DVCC 3.3 V or 5 V
• 775 mW Power Dissipation

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