AD6645-80/PCBZ

Manufacturer Part NumberAD6645-80/PCBZ
DescriptionBOARD EVAL ADC 80MSPS AD6645
ManufacturerAnalog Devices Inc
SeriesSoftCell®
AD6645-80/PCBZ datasheet
 


Specifications of AD6645-80/PCBZ

Design ResourcesLow Jitter Sampling Clock Generator for High Performance ADCs Using AD9958/9858 and AD9515 (CN0109)Number Of Adc's1
Number Of Bits14Sampling Rate (per Second)80M
Data InterfaceParallelInputs Per Adc1 Differential
Input Range2.2 VppPower (typ) @ Conditions1.5W @ 80MSPS
Voltage Supply SourceAnalog and DigitalOperating Temperature-40°C ~ 85°C
Utilized Ic / PartAD6645 80MSPSLead Free Status / RoHS StatusLead free / RoHS Compliant
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FEATURES
SNR = 75 dB, f
15 MHz, up to 105 MSPS
IN
SNR = 72 dB, f
200 MHz, up to 105 MSPS
IN
SFDR = 89 dBc, f
70 MHz, up to 105 MSPS
IN
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
AV
DV
CC
CC
AIN
A1
TH1
TH2
AIN
ADC1
VREF
2.4V
ENCODE
INTERNAL
TIMING
ENCODE
GND
DMID
OVR
Rev. D
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
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.
Trademarks and registered trademarks are the property of their respective owners.
14-Bit, 80 MSPS/105 MSPS
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
AD6645
A2
TH3
TH4
DAC1
ADC2
5
DIGITAL ERROR CORRECTION LOGIC
DRY
D13
D12
D11
D10
D9
D8
MSB
Figure 1.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
A/D Converter
AD6645
TH5
ADC3
DAC2
5
D7
D6
D5
D4
D3
D2
D1
www.analog.com
©2002–2008 Analog Devices, Inc. All rights reserved.
6
D0
LSB

AD6645-80/PCBZ Summary of contents

  • Page 1

    ... 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 the fourth ...

  • Page 2

    ... ESD Caution...................................................................................7   Pin Configuration and Function Descriptions ..............................8   Typical Performance Characteristics ..............................................9   Equivalent Circuits ......................................................................... 14   Terminology .................................................................................... 15   Theory of Operation ...................................................................... 17   Applying the AD6645 ................................................................ 17   Layout Information ........................................................................ 19   Jitter Considerations .................................................................. 19   Outline Dimensions ....................................................................... 24   Ordering Guide .......................................................................... 24   7/03—Rev Rev. B. Changes to Title ................................................................................ 1 Changes to Features ...

  • Page 3

    ... VREF should be AD6645 Unit Bits LSB LSB ppm/°C ppm/°C mV p-p kΩ ...

  • Page 4

    ... V 70.0 25°C V 63.5 Rev Page AD6645ASQ-105/AD6645ASV-105 Max Min Typ 0.4 10 2.5 CMOS 2.85 DV − 0.5 0.2 Twos complement 3.3 V; ENCODE, ENCODE , AD6645ASQ-105/ AD6645ASV-105 Max Min Typ Max Unit 75 72.5 74.5 dB 72.0 73.5 dB 73.0 dB 72 72.5 74.5 dB 73 ...

  • Page 5

    ... Max Unit 96.0 dBc dBc 86.0 95.0 dBc 90.0 dBc 90.0 dBc 88.0 dBc 98.0 dBFS 98.0 dBFS 98.0 dBFS 90 dBc 270 MHz AD6645ASQ-105/ AD6645ASV-105 Max Min Typ 105 30 4.286 4.75 4.286 4.75 9.5 3.1 1.0 2 ENCH DR 9.4 5.7 6.75 7.0 2 ...

  • Page 6

    ... ENCH ENCH ENCL t ENC E_FL E_DR N – – S_DR t DR Figure 2. Timing Diagram Rev Page AD6645ASQ-105/ AD6645ASV-105 Typ Max Min Typ 5 5 Note 5 Note 5 7.2 7.9 5.1 5 Note 5 Note 5 3.6 5.1 0.6 2.1 −500 −500 0.1 0 E_RL H_E and duty cycle. ...

  • Page 7

    ... Exposure to absolute maximum rating conditions for extended periods may affect device reliability. THERMAL RESISTANCE The heat sink of the AD6645ASVZ, 52-lead TQFP_EP (SV-52-1) package must be soldered to the PCB GND plane to meet thermal specifications. Table 6. Thermal Characteristics Package Type ...

  • Page 8

    ... DRY 53 (EPAD) Exposed Paddle (EPAD PIN 1 GND 2 IDENTIFIER VREF 3 GND 4 5 AD6645 6 TOP VIEW GND 7 (Not to Scale GND 10 AIN 11 AIN 12 GND Figure 3. Pin Configuration Description 3.3 V Power Supply (Digital) Output Stage Only. CC Ground. 2.4 V Reference. Bypass to ground with a 0.1 μF microwave chip capacitor. ...

  • Page 9

    ... FREQUENCY (MHz) Figure 7. Single Tone @ 69.1 MHz ENCODE = 80MSPS AIN = 150MHz @ –1dBFS SNR = 73.0dB SFDR = 70.0dBc FREQUENCY (MHz) Figure 8. Single Tone @ 150 MHz ENCODE = 80MSPS AIN = 200MHz @ –1dBFS SNR = 72.0dB SFDR = 64.0dBc FREQUENCY (MHz) Figure 9. Single Tone @ 200 MHz AD6645 ...

  • Page 10

    ... AD6645 75.5 75 –40°C 74 +85°C 74 +25°C 73.5 73.0 72.5 ENCODE = 80MSPS @ AIN = –1dBFS TEMP = –40°C, +25°C, +85°C 72 FREQUENCY (MHz) Figure 10. Signal-to-Noise Ratio (SNR) vs. Frequency –40°C, +85° ENCODE = 80MSPS @ AIN = –1dBFS TEMP = –40°C, +25°C, +85° ANALOG INPUT FREQUENCY (MHz) Figure 11 ...

  • Page 11

    ... Figure 20. Two-Tone SFDR @ 55.25 MHz and 56.25 MHz 105 Figure 21. SNR, Worst-Case Spurious vs. Encode @ 69.1 MHz Rev Page AD6645 FREQUENCY (MHz) dBFS dBc SFDR = 90dB REFERENCE LINE –67 –57 –47 –37 –27 –17 INPUT POWER LEVEL ( dBFS) WORST SPUR @ AIN = 69.1MHz SNR @ AIN = 69 ...

  • Page 12

    ... AD6645 0 ENCODE = 80.0MSPS –10 AIN = 30.5MHz @ –29.5dBFS NO DITHER –20 –30 –40 –50 –60 –70 –80 2 –90 6 –100 3 –110 5 –120 –130 FREQUENCY (MHz) Figure 22 Sample FFT Without Dither 110 ENCODE = 80.0MSPS AIN = 30.5MHz 100 NO DITHER SFDR = 90dB 30 REFERENCE LINE ANALOG INPUT LEVEL (dBFS) Figure 23 ...

  • Page 13

    ... Figure 31. W-CDMA Tone @ 190 MHz, Encode = 61.44 MSPS Rev Page ENCODE = 76.8MSPS AIN = W-CDMA @ 140MHz FREQUENCY (MHz) ENCODE = 61.44MSPS AIN = W-CDMA @ 190MHz 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 27.5 30.0 FREQUENCY (MHz) AD6645 ...

  • Page 14

    ... AD6645 EQUIVALENT CIRCUITS AIN BUF 500Ω BUF 500Ω AIN BUF V CL Figure 32. Analog Input Stage LOADS 10kΩ ENCODE 10kΩ LOADS Figure 33. Encode Inputs REF CURRENT MIRROR C1, C2 Figure 34. Compensation Pin T/H VREF T 10kΩ ENCODE 10kΩ ...

  • Page 15

    ... The ratio of the rms signal amplitude (set below full scale) to the rms value of the sum of all other spectral components, excluding the first five harmonics and dc. Rev Page − ⎛ FS SNR = × × ⎜ dBm dBc 001 10 NOISE ⎝ 10 AD6645 − ⎞ Signal ⎟ dBFS ⎠ ...

  • Page 16

    ... AD6645 Spurious-Free Dynamic Range (SFDR) The ratio of the rms signal amplitude to the rms value of the peak spurious spectral component. The peak spurious component may or may not be a harmonic. May be reported in dBc (that is, degrades as signal level is lowered) or dBFS (always related back to converter full scale). ...

  • Page 17

    ... RF transformer. The back-to-back Schottky diodes across the transformer secondary limit excessive amplitude swings from the clock into the AD6645 to approximately 0.8 V p-p differential. This helps to prevent the large voltage swings of the clock from feeding through to other portions of the AD6645 and limits the noise presented to the encode inputs ...

  • Page 18

    ... Place the series resistors as close AIN to the AD6645 as possible to limit the amount of current that can flow into the output stage. These switching currents are confined between ground and DV because they can add appreciably to the dynamic switching currents of the AD6645 ...

  • Page 19

    ... The pinout of the AD6645 facilitates ease of use in the implementation of high frequency, high resolution design practices. All of the digital outputs are segregated to two sides of the chip, with the inputs on the opposite side for isolation purposes ...

  • Page 20

    ... AD6645 Table 9. AD6645/PCB Bill of Materials Quantity Quantity 80 MSPS 105 MSPS Reference PCB 4 4 C1, C2, C31, C38 C10, C16, 1 C30 , C32 9 9 C4, C15, C22 to C26, C29, (C33 (C34) , C39 (C5, C6 C11 to C14, C17 to C21, C40 (C27, C28 CR1 (J3 (R1 (R2 (R3 to R5) ...

  • Page 21

    ... AC-coupled encode is standard: C5, C6, C33, C34, R1, R11 to R14, and U8 are not installed. If PECL encode is required, CR1 and T2 are not installed. Description IC, SOIC-8, differential receiver Clock oscillator, 80 MHz Pin sockets, closed end Circuit board support Rev Page AD6645 Manufacturer Supplier Part No. Motorola MC100LVEL16 CTS Reeves MXO45-80 ...

  • Page 22

    ... AD6645 Figure 43. Evaluation Board Schematic Rev Page 7- ...

  • Page 23

    ... Figure 44. Top Signal Level Figure 45. 5.0 V Plane Layer 3 and 3.3 V Plane Layer 4 Figure 46. Ground Plane Layer 2 and Ground Plane Layer 5 Figure 47. Bottom Signal Layer Rev Page AD6645 ...

  • Page 24

    ... AD6645ASQ-105 −10°C to +85°C 1 AD6645ASQZ-105 −10°C to +85°C 1 AD6645ASVZ-105 −10°C to +85°C 1 AD6645-80/PCBZ 1 AD6645-105/PCBZ RoHS Compliant Part. ©2002–2008 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D02647-0-10/08(D) 12.20 2.65 12 ...