14-Bit, 80 MSPS/105 MSPS A/D Converter AD6645

FEATURES

• SNR = 75 dB, f_IN 15 MHz, up to 105 MSPS
• SNR = 72 dB, f_IN 200 MHz, up to 105 MSPS
• SFDR = 89 dBc, fIN 70 MHz, up to 105 MSPS
• 100 dBFS multitone SFDR
• IF sampling to 200 MHz
• Sampling jitter: 0.1 ps
• 1.5 W power dissipation
• Differential analog inputs
• Pin compatible to AD6644
• Twos complement digital output format
• 3.3 V CMOS compatible
• Data-ready for output latching

APPLICATIONS

• Multichannel, multimode receivers
• Base station infrastructures
• AMPS, IS-136, CDMA, GSM, W-CDMA
• Single channel digital receivers
• Antenna array processing
• Communications instrumentation
• Radars, infrared imaging
• Instrumentation

GENERAL DESCRIPTION

The AD6645 is a high speed, high performance, monolithic 14-bit analog-to-digital converter (ADC). All necessary functions, including track-and-hold (T/H) and reference, are included on the chip to provide a complete conversion solution. The AD6645 provides CMOS-compatible digital outputs. It is the fourth generation in a wideband ADC family, preceded by the AD9042 (12-bit, 41 MSPS), the AD6640 (12-bit, 65 MSPS, IF sampling), and the AD6644 (14-bit, 40 MSPS/65 MSPS).

Designed for multichannel, multimode receivers, the AD6645 is part of the Analog Devices, Inc., SoftCell® transceiver chipset. The AD6645 maintains 100 dB multitone, spurious-free dynamic range (SFDR) through the second Nyquist band. This breakthrough performance eases the burden placed on multimode digital receivers (software radios) that are typically limited by the ADC. Noise performance is exceptional; typical signal-to-noise ratio (SNR) is 74.5 dB through the first Nyquist band.

The AD6645 is built on the Analog Devices extra fast complementary bipolar (XFCB) process and uses an innovative, multipass circuit architecture. Units are available in thermally enhanced 52-lead PowerQuad 4 (LQFP_PQ4) and 52-lead exposed pad (TQFP_EP) packages specified from −40°C to +85°C at 80 MSPS and −10°C to +85°C at 105 MSPS.

PRODUCT HIGHLIGHTS

1. IF Sampling. The AD6645 maintains outstanding ac performance up to input frequencies of 200 MHz, suitable for multicarrier 3G wideband cellular IF sampling receivers.

2. Pin Compatibility. The ADC has the same footprint and pin layout as the AD6644 14-bit, 40 MSPS/65 MSPS ADC.

3. SFDR Performance and Oversampling. Multitone SFDR performance of 100 dBFS can reduce the requirements of high end RF components and allows the use of receive signal processors, such as the AD6620, AD6624/AD6624A, or AD6636.

FUNCTIONAL BLOCK DIAGRAM

ABSOLUTE MAXIMUM RATINGS

Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

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