GENERAL DESCRIPTION

The AD6643 is an 11-bit, 200 MSPS/250 MSPS, dual-channel intermediate frequency (IF) receiver specifically designed to support multi-antenna systems in telecommunication applications where high dynamic range performance, low power, and small size are desired.

The device consists of two high performance analog-to-digital converters (ADCs) and noise shaping requantizer (NSR) digital blocks. Each ADC consists of a multistage, differential pipelined architecture with integrated output error correction logic, and each ADC features a wide bandwidth switched capacitor sampling network within the first stage of the differential pipeline. An integrated voltage reference eases design considerations. A duty cycle stabilizer (DCS) compensates for variations in the ADC clock duty cycle, allowing the converters to maintain excellent performance.

FEATURES

11-bit, 250 MSPS output data rate per channel

Performance with NSR enabled

SNR: 74.5 dBFS in a 55 MHz band to 90 MHz at 250 MSPS

SNR: 72.0 dBFS in a 82 MHz band to 90 MHz at 250 MSPS

Performance with NSR disabled

SNR: 66.2 dBFS up to 90 MHz at 250 MSPS

SFDR: 85 dBc up to 185 MHz at 250 MSPS

Total power consumption: 706 mW at 200 MSPS

1.8 V supply voltages

LVDS (ANSI-644 levels) outputs

Integer 1-to-8 input clock divider (625 MHz maximum input)

Internal ADC voltage reference

Flexible analog input range

1.4 V p-p to 2.0 V p-p (1.75 V p-p nominal)

Differential analog inputs with 400 MHz bandwidth

95 dB channel isolation/crosstalk

Serial port control

Energy saving power-down modes

APPLICATIONS

Communications

Diversity radio and smart antenna (MIMO) systems

Multimode digital receivers (3G)

WCDMA, LTE, CDMA2000

WiMAX, TD-SCDMA

I/Q demodulation systems

General-purpose software radios