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, f
IN
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
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.
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
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.
Pin Compatibility. The ADC has the same footprint and
pin layout as the AD6644 14-bit, 40 MSPS/65 MSPS ADC.
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.
2.
3.
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
AV
CC
DV
CC
FUNCTIONAL BLOCK DIAGRAM
AD6645
AIN
AIN
A1
TH1
TH2
A2
TH3
TH4
TH5
ADC3
VREF
ADC1
2.4V
5
DAC1
ADC2
5
DAC2
6
ENCODE
ENCODE
INTERNAL
TIMING
DIGITAL ERROR CORRECTION LOGIC
GND
DMID
OVR
DRY
D13
MSB
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
LSB
Figure 1.
Rev. D
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
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Fax: 781.461.3113 ©2002–2008 Analog Devices, Inc. All rights reserved.
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