Analog Devices AD6620 a Datasheet

67 MSPS Digital Receive

a

FEATURES
High Input Sample Rate

67 MSPS Single Channel Real

33.5 MSPS Diversity Channel Real

33.5 MSPS Single Channel Complex

NCO Frequency Translation

Worst Spur Better than –100 dBc
Tuning Resolution Better than 0.02 Hz

2nd Order Cascaded Integrator Comb FIR Filter

Linear Phase, Fixed Coefficients
Programmable Decimation Rates: 2, 3 . . . 16

5th Order Cascaded Integrator Comb FIR Filter

Linear Phase, Fixed Coefficients
Programmable Decimation Rates: 1, 2, 3 . . . 32

Programmable Decimating RAM Coefficient FIR Filter

Up to 134 Million Taps per Second
256 20-Bit Programmable Coefficients
Programmable Decimation Rates: 1, 2, 3 . . . 32

Bidirectional Synchronization Circuitry

Phase Aligns NCOs
Synchronizes Data Output Clocks

Serial or Parallel Baseband Outputs

Pin Selectable Serial or Parallel
Serial Works with SHARC

DSPs

16-Bit Parallel Port, Interleaved I and Q Outputs

Two Separate Control and Configuration Ports

Generic ␮P Port, Serial Port

3.3 V Optimized CMOS Process
JTAG Boundary Scan

GENERAL DESCRIPTION

The AD6620 is a digital receiver with four cascaded signal­processing elements: a frequency translator, two fixed­coefficient decimating filters, and a programmable coefficient
decimating filter. All inputs are 3.3 V LVCMOS compatible.
All outputs are LVCMOS and 5 V TTL compatible.

As ADCs achieve higher sampling rates and dynamic range, it
becomes increasingly attractive to accomplish the final IF stage
of a receiver in the digital domain. Digital IF Processing is less
expensive, easier to manufacture, more accurate, and more
flexible than a comparable highly selective analog stage.

The AD6620 diversity channel decimating receiver is designed
to bridge the gap between high-speed ADCs and general pur­pose DSPs. The high resolution NCO allows a single carrier to
be selected from a high speed data stream. High dynamic range
decimation filters with a wide range of decimation rates allow

®

, ADSP-21xx, Most Other

Signal Processor

AD6620

FUNCTIONAL BLOCK DIAGRAM

I

REAL,

DUAL REAL,

OR COMPLEX

INPUTS

AD6620

COMPLEX

NCO

–SINCOS

Q

FILTERS

both narrowband and wideband carriers to be extracted. The
RAM-based architecture allows easy reconfiguration for multi­mode applications.

The decimating filters remove unwanted signals and noise from
the channel of interest. When the channel of interest occupies
less bandwidth than the input signal, this rejection of out-of­band noise is called “processing gain.” By using large decimation
factors, this “processing gain” can improve the SNR of the
ADC by 36 dB or more. In addition, the programmable RAM
Coefficient filter allows antialiasing, matched filtering, and
static equalization functions to be combined in a single, cost­effective filter.

The input port accepts a 16-bit Mantissa, a 3-bit Exponent,
and an A/B Select pin. These allow direct interfacing with the
AD6600, AD6640, AD6644, AD9042 and most other high­speed ADCs. Three input modes are provided: Single Channel
Real, Single Channel Complex, and Diversity Channel Real.

When paired with an interleaved sampler such as the AD6600,
the AD6620 can process two data streams in the Diversity
Channel Real input mode. Each channel is processed with coher­ent frequency translation and output sample clocks. In addition,
external synchronization pins are provided to facilitate coherent
frequency translation and output sample clocks among several
AD6620s. These features can ease the design of systems with
diversity antennas or antenna arrays.

Units are packaged in an 80-lead PQFP (plastic quad flatpack)
and specified to operate over the industrial temperature range
(–40°C to +85°C).

II

CIC

QQ

EXTERNAL

SYNC

CIRCUITRY

FIR

FILTER

JTAG
PORT

OUTPUT
FORMAT

SERIAL OR
PARALLEL
OUTPUTS

␮P

OR SERIAL

CONTROL

SHARC is a registered trademark of Analog Devices, Inc.

REV. A

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. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] © Analog Devices, Inc., 2001

AD6620

TABLE OF CONTENTS

GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 1

ARCHITECTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

TIMING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . 11

EXPLANATION OF TEST LEVELS . . . . . . . . . . . . . . . . 11

ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

PIN FUNCTION DESCRIPTIONS . . . . . . . . . . . . . . . . . 12

PIN CONFIGURATIONS . . . . . . . . . . . . . . . . . . . . . . . . . 13

INPUT DATA PORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

OUTPUT DATA PORT . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

FREQUENCY TRANSLATOR . . . . . . . . . . . . . . . . . . . . . 19

SECOND ORDER CASCADED INTEGRATOR

COMB FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

FIFTH ORDER CASCADED INTEGRATOR

COMB FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

RAM COEFFICIENT FILTER . . . . . . . . . . . . . . . . . . . . . 25

CONTROL REGISTERS AND ON-CHIP RAM . . . . . . . 27

PROGRAMMING THE AD6620 . . . . . . . . . . . . . . . . . . . 30

ACCESS PROTOCOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

MICROPORT CONTROL . . . . . . . . . . . . . . . . . . . . . . . . 32

SERIAL PORT CONTROL . . . . . . . . . . . . . . . . . . . . . . . . 35

JTAG BOUNDARY SCAN . . . . . . . . . . . . . . . . . . . . . . . . 37

APPLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . 44

3

EXP[2:0]

IN[15:0]

FREQUENCY

TRANSLATOR

16

PHASE

OFFSET

CLK

A/B

RESET

SYNC NCO

SYNC CIC

SYNC

RCF

16

COMPLEX

NCO

INPUT

DATA

I

Q

TIMING

SYNC

3

18

EXP

SCALING

18

EXPLNV,
EXPOFF

f

SAMP

REAL, DUAL, COMPLEX

FIXED OR WITH EXPONENT

I/O

TCK TMS TDI TDO

TRST

INTERLEAVE

CIC2

SCALING

NCO FREQUENCY

PHASE OFFSET

DITHER

SYNC MASK

INPUT MODE

SYNC M/S

JTAG

MULTI-

PLEXER

M

CICS

f

SAMP2

CIC2, CIC5

DECIMATE FACTORS

SCALE FACTORS

CONTROL REGISTERS

MICROPORT AND

SERIAL ACCESS

MICROPROCESSOR INTERFACE

D[7:0] A[2:0]

Figure 1. Block Diagram

ARCHITECTURE

As shown in Figure 1, the AD6620 has four main signal pro­cessing stages: a Frequency Translator, two Cascaded Integrator
Comb FIR Filters (CIC2, CIC5), and a RAM Coefficient FIR
Filter (RCF). Multiple modes are supported for clocking data
into and out of the chip. Programming and control is accom­plished via serial and microprocessor interfaces.

Input data to the chip may be real or complex. If the input data
is real, it may be clocked in as a single channel or interleaved
with a second channel. The two-channel input mode, called
Diversity Channel Real, is typically used in diversity receiver
applications. Input data is clocked in 16-bit parallel words,
IN[15:0]. This word may be combined with exponent input bits
EXP[2:0] when the AD6620 is being driven by floating-point or
gain-ranging analog-to-digital converters such as the AD6600.

Frequency translation is accomplished with a 32-bit complex
Numerically Controlled Oscillator (NCO). Real data entering
this stage is separated into in-phase (I) and quadrature (Q)
components. This stage translates the input signal from a digital
intermediate frequency (IF) to baseband. Phase and amplitude
dither may be enabled on-chip to improve spurious performance
of the NCO. A phase offset word is available to create a known
phase relationship between multiple AD6620s.

Following frequency translation is a fixed coefficient, high speed
decimating filter that reduces the sample rate by a program­mable ratio between 2 and 16. This is a second order, cascaded
integrator comb FIR filter shown as CIC2 in Figure 1. (Note:
Decimation of 1 in CIC2 requires 2× or greater clock into
AD6620). The data rate into this stage equals the input data
rate, f
the decimation factor, M

CIC5

SCALING

RCF COEFFICIENTS

NUMBER OF TAPS

DECIMATE FACTOR

ADDRESS OFFSET

R/W

DS

(W/R)

(R/D)

. The data rate out of CIC2, f

SAMP

CIC2

INTERLEAVE

23

SCALING, S

PARALLEL

16

M

OUTPUT

SCALE

FACTOR

DTACKCS

(RDY)

CICS

MODE

MULTI-

PLEXER

f

SAMP5

PAR/SER

.

DE-

23

OUTPUT

OUT

SAMP2

I-RAM

256 ⴛ 18

C-RAM

256 ⴛ 20

Q-RAM

256 ⴛ 18

MULTIPLEXER

SERIAL

, is determined by

RCF

M

RCF

DV

OUT

I/Q

OUT

A/B

OUT

PARALLEL

OUTPUTS

AND

SERIAL I/O

16

OUT[15:0]
SCLK
SDI
SDO
SDFS
SDFE
SBM
WL[1:0]
AD
SDIV[3:0]

–2–

REV. A

AD6620

Following CIC2 is the second fixed-coefficient decimating filter.
This filter, CIC5, further reduces the sample rate by a program­mable ratio from 1 to 32. The data rate out of CIC5, f
determined by the decimation factors of M

CIC5

and M

SAMP5

CIC2

, is

.

Each CIC stage is a FIR filter whose response is defined by the
decimation rate. The purpose of these filters is to reduce the
data rate of the incoming signal so that the final filter stage, a FIR
RAM coefficient sum-of-products filter (RCF), can calculate
more taps per output. As shown in Figure 1, on-chip multiplex­ers allow both CIC filters to be bypassed if a multirate clock
is used.

The fourth stage is a sum-of-products FIR filter with program­mable 20-bit coefficients, and decimation rates programmable
from 1 to 32. The RAM Coefficient FIR Filter (RCF in Figure

1) can handle a maximum of 256 taps.

WIDEBAND INPUT SPECTRUM

SIGNAL OF INTEREST "IMAGE"

C'

D'

–fS/2 –3fS/8 –5fS/16 –fS/4 –3fS/16 –fS/8 –fS /16

B'

A'

DC

Figure 2a. Wideband Input Spectrum (e.g., 30 MHz from High-Speed ADC)

The overall filter response for the AD6620 is the composite of
all three cascaded decimating filters: CIC2, CIC5, and RCF. Each
successive filter stage is capable of narrower transition band­widths but requires a greater number of CLK cycles to calculate
the output. More decimation in the first filter stage will minimize
overall power consumption. Data comes out via a parallel port
or a serial interface.

Figure 2 illustrates the basic function of the AD6620: to select
and filter a single channel from a wide input spectrum. The
frequency translator “tunes” the desired carrier to baseband.
CIC2 and CIC5 have fixed order responses; the RCF filter
provides the sharp transitions. More detail is provided in later
sections of the data sheet.

(–f

2 TO f

samp/

A

fS/16 fS/8 3fS/16 fS/4 5fS/16 fS/23fS/8

B

2)

samp/

SIGNAL OF

INTEREST

C

D

NCO "TUNES" SIGNAL TO BASEBAND

AFTER FREQUENCY TRANSLATION

A

–fS/2 –3fS/8 –5fS/16 –fS/4 –3fS/16 –fS/8 –fS/16 DC fS/16 fS/8 3fS/16 fS/4 5fS/16 fS/23fS/8

B

C

D

C'

D'

B'

Figure 2b. Frequency Translation (e.g., Single 1 MHz Channel Tuned to Baseband)

CIC2, CIC5, AND RCF

FREQUENCY

dBc

–100

–110

–120

–130

0

–10

–20

–30

–40

–50

–60

–70

–80

–90

A'

Figure 2c. Baseband Signal is Decimated and Filtered by CIC2, CIC5, RCF

–3–REV. A

AD6620–SPECIFICATIONS

RECOMMENDED OPERATING CONDITIONS

Test AD6620AS

Parameter Level Min Typ Max Unit

VDD I 3.0 3.3 3.6 V
T

AMBIENT

ELECTRICAL CHARACTERISTICS

Parameter (Conditions) Temp Level Min Typ Max Unit

LOGIC INPUTS

Logic Compatibility Full 3.3 V CMOS
Logic “1” Voltage Full I 2.0 VDD + 0.3 V
Logic “0” Voltage Full I –0.3 0.8 V
Logic “1” Current Full I 1 10 µA
Logic “0” Current Full I 1 10 µA
Input Capacitance 25°CV 4 pF

LOGIC OUTPUTS

Logic Compatibility Full 3.3 V CMOS/TTL
Logic “1” Voltage (I
Logic “0” Voltage (IOL = 1.0 mA) Full I 0.2 0.4 V

IDD SUPPLY CURRENT

CLK = 20 MHz
CLK = 65 MHz
Reset Mode

POWER DISSIPATION

CLK = 20 MHz
CLK = 65 MHz
Reset Mode

NOTES

1

Input-Only Pins: CLK, RESET, IN[15:0], EXP[2:0], A/B, PAR/SEL.

2

Bidirectional Pins: SYNC_NCO, SYNC_CIC, SYNC_RCF.

3

Microinterface Input Pins: DS (RD), R/W (WR), CS.

4

Microinterface Bidirectional Pins: A[2:0], D[7:0].

5

JTAG Input Pins: TRST, TCK, TMS, TDI.

6

Serial Mode Input Pins: SDI, SBM, WL[1:0], AD, SDIV[3:0].

7

Serial Mode Bidirectional Pins: SCLK, SDFS.

8

Output Pins: OUT[15:0], DV

9

Microinterface Output Pins: DTACK (RDY).

10

JTAG Output Pins: TDO.

11

Serial Mode Output Pins: SDO, SDFE.

12

Conditions for IDD @ 20 MHz. M

13

Conditions for IDD @ 65 MHz. M

14

Conditions for IDD in Reset (RESET = 0).

Specifications subject to change without notice.

1, 2, 3, 4, 5, 6, 7

2, 4, 7, 8, 9, 10, 11

12

13

14

12

13

14

(NOT 5 V TOLERANT)

= 0.5 mA) Full I 2.4 VDD – 0.2 V

OH

Full V 52 mA
Full I 167 227 mA
Full I 1 mA

Full V 170 mW
Full I 550 750 mW
Full I 3.3 mW

, A/B

, I/Q

OUT

CIC2

CIC2

OUT

= 2, M
= 2, M

OUT

CIC5

CIC5

.

= 2, M
= 2, M

= 1, 4 RCF taps of alternating positive and negative full scale.

RCF

= 1, 4 RCF taps of alternating positive and negative full scale.

RCF

IV –40 +25 +85 °C

Test AD6620AS

–4–

REV. A

AD6620

TIMING CHARACTERISTICS

(C

= 40 pF All Outputs)

LOAD

Test AD6620AS

Parameter (Conditions) Temp Level Min Typ Max Unit

CLK Timing Requirements:

t

CLK

t

CLK

t

CLKL

t

CLKH

CLK Period Full I 14.93
CLK Period Full I 15.4 ns
CLK Width Low Full IV 7.0 0.5 × t
CLK Width High Full IV 7.0 0.5 × t

1

CLK

CLK

ns

ns
ns

Reset Timing Requirements:

t

RESL

RESET Width Low Full I 30.0 ns

Input Data Timing Requirements:

t

SI

t

HI

Input2 to CLK Setup Time Full IV –1.0 ns
Input2 to CLK Hold Time Full IV 6.5 ns

Parallel Output Switching Characteristics:

t

DPR

t

DPF

t

DPR

t

DPF

t

DPR

t

DPF

t

DPR

t

DPF

CLK to OUT[15:0] Rise Delay Full IV 8.0 19.5 ns
CLK to OUT[15:0] Fall Delay Full IV 7.5 19.5 ns
CLK to DV
CLK to DV
CLK to IQ
CLK to IQ
CLK to AB
CLK to AB

Rise Delay Full IV 6.5 19.0 ns

OUT

Fall Delay Full IV 5.5 11.5 ns

OUT

Rise Delay Full IV 7.0 19.5 ns

OUT

Fall Delay Full IV 6.0 13.5 ns

OUT

Rise Delay Full IV 7.0 19.5 ns

OUT

Fall Delay Full IV 5.5 13.5 ns

OUT

SYNC Timing Requirements:

t

SY

t

HY

SYNC3 to CLK Setup Time Full IV –1.0 ns
SYNC3 to CLK Hold Time Full IV 6.5 ns

SYNC Switching Characteristics:

t

DY

CLK to SYNC4 Delay Time Full V 7.0 23.5 ns

Serial Input Timing:

t

SSI

t

HSI

t

HSRF

t

SSF

t

HSF

SDI to SCLKt Setup Time Full IV 1.0 ns
SDI to SCLKt Hold Time Full IV 2.0 ns
SDFS to SCLKu Hold Time Full IV 4.0 ns
SDFS to SCLKt Setup Time
SDFS to SCLKt Hold Time

5

5

Full IV 1.0 ns
Full IV 2.0 ns

Serial Frame Output Timing:

t

DSE

t

SDFEH

t

DSO

SCLK Switching Characteristics, SBM = “1”:
t

SCLK

t

SCLKL

t

SCLKH

t

SCLKD

SCLKu to SDFE Delay Time Full IV 3.5 11.0 ns
SDFE Width High Full V t

SCLK

ns

SCLKu to SDO Delay Time Full IV 4.5 11.0 ns

SCLK Period
SCLK Width Low Full V 0.5 × t
SCLK Width High Full V 0.5 × t

4

Full I 2 × t

CLK

SCLK

SCLK

ns
ns
ns

CLK to SCLK Delay Time Full V 6.5 13.0 ns

Serial Frame Timing, SBM = “1”:
t

DSF

t

SDFSH

SCLKu to SDFS Delay Time Full IV 1.0 4.0 ns
SDFS Width High Full V t

SCLK

ns

SCLK Timing Requirements, SBM = “0”:
t

SCLK

t

SCLKL

t

SCLKH

NOTES

1

This specification valid for VDD >= 3.3 V. t

2

Specification pertains to: IN[15:0], EXP[2:0], A/B.

3

Specification pertains to: SYNC_NCO, SYNC_CIC, SYNC_RCF.

4

SCLK period will be ≥ 2 × t

5

SDFS setup and hold time must be met, even when configured as outputs, since internally the signal is sampled at the pad.

Specifications subject to change without notice.

SCLK Period Full I 15.4 ns
SCLK Width Low Full IV 0.4 × t
SCLK Width High Full IV 0.4 × t

and t

CLKL

when AD6620 is Serial Bus Master (SBM = 1) depending on the SDIV word.

CLK

still apply.

CLKH

SCLK

SCLK

0.5 × t

0.5 × t

SCLK

SCLK

ns
ns

–5–REV. A

AD6620
TIMING CHARACTERISTICS

(C

= 40 pF All Outputs)

LOAD

Test AD6620AS

Parameter (Conditions) Temp Level Min Typ Max Unit

MICROPROCESSOR PORT, MODE = 0

MODE0 Input Timing Requirements:

t

SC

t

HC

t

HA

t

ZR

t

ZD

t

SAM

Control1 to CLK Setup Time Full IV 3.0 ns
Control1 to CLK Hold Time Full IV 5.0 ns
Address2 to CLK Hold Time Full IV 3.0 ns

CS to Data Enabled Time Full IV 5.0 ns
CS to Data Disabled Time Full IV 5.0 ns
CS to Address/Data Setup Time Full IV 0.0 ns

MODE0 Read Switching Characteristics:

t

DD

t

RDY

CLK to Data Valid Time Full I 10.0 15.0 30.0 ns
RD to RDY Time Full IV 4.0 19.5 ns

MODE0 Write Timing Requirements:

t

SC

t

HC

t

HM

t

HA

t

SAM

Control1 to CLK Setup Time Full IV 3.0 ns
Control1 to CLK Hold Time Full IV 5.0 ns
Micro Data3 to CLK Hold Time Full IV 3.0 ns
Address2 to CLK Hold Time Full IV 3.0 ns
Address/Data Setup Time to CS Full IV 0.0 ns

MODE0 Write Switching Characteristics:

t

RDY

RD to RDY Time Full IV 4.0 19.5 ns

MICROPROCESSOR PORT, MODE = 1

MODE1 Input Timing Requirements:

t

SC

t

HC

t

HA

t

ZR

t

ZD

t

SAM

Control1 to CLK Setup Time Full IV 3.0 ns
Control1 to CLK Hold Time Full IV 5.0 ns
Address2 to CLK Hold Time Full IV 3.0 ns

CS to Data Enabled Time Full IV 5.0 ns
CS to Data Disabled Time Full IV 5.0 ns
Address/Data Setup Time to CS Full IV 0.0 ns

MODE1 Read Switching Characteristics:

t

DD

t

DTACK

CLK to Data Valid Time Full I 10.0 30.0 ns
CLK to DTACK Time Full V 5.5 15.5 ns

MODE1 Write Timing Requirements:

t

SC

t

HC

t

HM

t

HA

t

SAM

Control1 to CLK Setup Time Full IV 0.0 ns
Control1 to CLK Hold Time Full IV 5.0 ns
Micro Data3 to CLK Hold Time Full IV 6.5 ns
Address2 to CLK Hold Time Full IV 3.0 ns
Address/Data Setup Time to CS Full IV 0.0 ns

MODE1 Write Switching Characteristic:

t

DTACK

NOTES

1

Specification pertains to: R/W (WR), DS (RD), CS.

2

Specification pertains to: A[2:0].

3

Specification pertains to: D[7:0].

Specifications subject to change without notice.

CLK to DTACK Time Full V 5.5 15.5 ns

–6–

REV. A

TIMING DIAGRAMS

t

RESL

RESET

AD6620

CLK, INPUTS, PARALLEL OUTPUTS

RESET with PAR/SER = “1” establishes Parallel Outputs active.

t

CLK

t

CLKH

CLK

t

CLKL

Figure 3. CLK Timing Requirements

CLK

t

IN[15:0]

EXP[2:0]

A/B

t

SI

HI

DATA

Figure 4. Input Data Timing Requirements

SYNC PULSES: SLAVE OR MASTER

CLK

t

t

HY

SY

SYNC

NCO

SYNC

CIC

RCF

SYNC

NOTE:
IN THE SLAVE MODE WITH SINGLE CHANNEL OPERATION, THE WIDTH
OF THE SYNC_NCO SHOULD BE ONE SAMPLE CLOCK CYCLE. IN DUAL
CHANNEL MODE, THE PULSEWIDTH SHOULD BE TWO SAMPLE CLOCK
CYCLES. IF A PULSE LONGER THAN SPECIFIED IS USED, THE NCO WILL
BE INHIBITED AND NOT INCREMENT PROPERLY.

Figure 6. SYNC Slave Timing Requirements

t

t

CLK

CHP

CLK

t

CS

IN[15:0]

N

E[2:0]

t

CPL

t

CH

N+1

CLK

DV

OUT

I/Q

OUT

OUT[15:0]

t

DPR

VALID OUTPUT DATA

I

I

A

t

DPF

Q

Q

I

I

A

B

Figure 5. Parallel Output Switching Characteristics

t

DPF

A/B

Figure 7. SYNC Master Delay

Q

Q

B

Figure 8. Reset Timing Requirements

–7–REV. A

AD6620

SERIAL PORT: BUS MASTER

RESET with PAR/SER = “0” establishes Serial Port active.
SBM = “1” puts AD6620 in Serial Bus Master mode SCLK is
output; SDFS is output.

CLK

t

SCLKD

t

SCLK

t

SCLKH

SCLK

t

SCLKL

Figure 9. SCLK Switching Characteristics

SCLK

SERIAL PORT: CASCADE MODE

RESET with PAR/SER = “0” establishes Serial Port active.
SBM = “0” puts AD6620 in Serial Port Cascade mode, SCLK
is input; SDFS is input.

t

SCLK

t

SCLKH

SCLK

t

SCLKL

Figure 13. SCLK Timing Requirements

SCLK

t

t

SSI

HSI

SDI

DATA

t

SSI

t

HSI

DATASDI

Figure 10. Serial Input Data Timing Requirements

t

SCLK

SDFS

SDFE

DSF

t

SDFSH

t

DSE

Figure 11. Serial Frame Switching Characteristics

t

DSO

SCLK

t

SDFEH

Figure 14. Serial Input Data Timing Requirements

t

HSRF

SCLK

SDO

SDFS

I

15

t

HSF

t

SSF

I

14

Q

1

Figure 15. SDO/SDFS Timing Requirements

t

DSE

Q

1

SCLK

SDO

SDFE

t

DSO

I

15

I

14

Q

0

Q

0

t

SDFEH

SDO

I

15

I

14

I

13

Figure 12. Serial Output Data Switching Characteristics

–8–

Figure 16. SDO, SDFE Switching Characteristics

REV. A

MICROPORT MODE0, READ

Timing is synchronous to CLK; MODE = 0.

AD6620

t

DD

1

CLK

2

WR

2

RD

3

CS

t

D[7:0]

A[2:0]

1

RDY

NOTES:

1

RDY IS DRIVEN LOW ASYNCHRONOUSLY BY RD AND CS GOING LOW AND RETURNS HIGH ON THE RISING EDGE

OF CLK "N+3" FOR INTERNAL ACCESS (A[2:0] = 000), CLK "N+2" OTHERWISE.

2

THE SIGNAL, WR, MAY REMAIN HIGH AND RD MAY REMAIN LOW TO CONTINUE READ MODE.

3

CS MUST RETURN TO HIGH STATE AND BE SAMPLED BY CLK (N+4 SHOWN) TO COMPLETE READ.

ZR

t

SAM

N N+1 N+2 N+3 N+4 N

t

SC

ADDRESS VALID

t

RDY

t

HC

DATA VALID

t

RDY

t

HC

t

ZD

t

HA

Figure 17. MODE0 Read Timing Requirements and Switching Characteristics

MICROPORT MODE0, WRITE

Timing is synchronous to CLK; MODE = 0.

t

SC

1

CLK

2

WR

2

RD

3

CS

t

SAM

D[7:0]

t

SAM

A[2:0]

RDY

NOTES:

1

RDY IS DRIVEN LOW ASYNCHRONOUSLY BY WR AND CS GOING LOW AND RETURNS HIGH ON THE

RISING EDGE OF CLK "N+2".

2

THESE SIGNALS (R/W AND DS) MAY REMAIN IN LOW STATE TO CONTINUE WRITING DATA.

3

CS MUST RETURN TO HIGH STATE AND BE SAMPLED BY CLK (N+3 SHOWN) TO COMPLETE WRITE.

* THE NEXT WRITE MAY BE INITIATED ON CLK, N*.

t

HC

N N+1 N+2 N+3 N*

t

SC

t

HC

t

HM

DATA VALID

t

HA

ADDRESS VALID

t

t

RDY

RDY

Figure 18. MODE0 Write Timing Requirements and Switching Characteristics

–9–REV. A

AD6620

MICROPORT MODE1, READ

Timing is synchronous to CLK; MODE = 1.

CLK

1

N

t

N+1 N+2

DD

N+3

t

HC

N+4

N

2

R/W

2

DS

3

CS

D[7:0]

A[2:0]

DTACK

NOTES:

1

DTACK IS DRIVEN LOW ON THE RISING EDGE OF CLK "N+3" FOR INTERNAL ACCESS (A[2:0] = 000),

CLK "N=2" OTHERWISE.

2

THE SIGNAL, R/W MAY REMAIN HIGH AND DS MAY REMAIN LOW TO CONTINUE READ MODE.

3

CS MUST RETURN TO HIGH STATE AND BE SAMPLED BY CLK (N+4 SHOWN) TO COMPLETE ACCESS

AND FORCE DTACK HIGH.

t

SAM

t

SC

t

ZR

Figure 19. MODE1 Read Timing Requirements and Switching Characteristics

MICROPORT MODE1, WRITE

Timing is synchronous to CLK; MODE = 1.

ADDRESS VALID

t

DTACK

DATA VALID

t

t

SC

HC

t

ZD

t

HA

t

DTACK

CLK

R/W

DS

CS

D[7:0]

A[2:0]

DTACK

t

SC

1

2

2

3

t

SAM

t

SAM

NOTES:

1

ON RISING EDGE OF "N+3" CLK, DTACK IS DRIVEN LOW.

2

THESE SIGNALS (R/W AND DS) MAY REMAIN IN LOW STATE TO CONTINUE WRITING DATA.

3

CS MUST RETURN TO HIGH STATE AND BE SAMPLED BY CLK (N+3 SHOWN) TO COMPLETE WRITE

AND FORCE DTACK HIGH.

* THE NEXT WRITE MAY BE INITIATED ON CLK, N*.

N

N+1 N+2

DATA VALID

ADDRESS VALID

t

HC

t

HM

t

HA

t

DTACK

N+3

t

t

HC

SC

t

DTACK

N*

Figure 20. MODE1 Write Timing Requirements and Switching Characteristics

–10–

REV. A

AD6620

ABSOLUTE MAXIMUM RATINGS*

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +4.5 V

Input Voltage . . . –0.3 V to VDD + 0.3 V (Not 5 V Tolerant)

Output Voltage Swing . . . . . . . . . . . . –0.3 V to VDD + 0.3 V

Load Capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 pF

Junction Temperature Under Bias . . . . . . . . . . . . . . . . 130°C

Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C

Lead Temperature (5 sec) . . . . . . . . . . . . . . . . . . . . . . 280°C

*Stresses greater than those listed above may cause permanent damage to the

device. These are stress ratings only; functional operation of the device at these or
any other conditions greater than those indicated in the operational sections of this
specification is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.

Thermal Characteristics

EXPLANATION OF TEST LEVELS

I. 100% Production Tested.
II. 100% Production Tested at 25°C, and Sampled Tested at

Specified Temperatures.

III. Sample Tested Only.

IV. Parameter Guaranteed by Design and Analysis.

V. Parameter is Typical Value Only.
VI. 100% Production Tested at 25°C, and Sampled Tested at

Temperature Extremes.

80-Lead Plastic Quad Flatpack:

θ

= 44°C/W

JA

= 11°C/W

θ

JC

ORDERING GUIDE

Model Temperature Range Package Description Option

AD6620AS –40°C to +85°C (Ambient) 80-Lead PQFP (Plastic Quad Flatpack) S-80A
AD6620S/PCB Evaluation Board with AD6620AS and Software

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the AD6620 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high-energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.

Package

WARNING!

ESD SENSITIVE DEVICE

–11–REV. A

AD6620

PIN FUNCTION DESCRIPTIONS

Name Type Description

VDD P 3.3 V Supply
VSS G Ground
CLK I Input Clock
RESET I Active Low Reset Pin
IN[15:0] I Input Data (Mantissa)
EXP[2:0] I Input Data (Exponent)
A/B I Channel (A/B) Select
SYNC_NCO I/O Sync Signal for NCO
SYNC_CIC I/O Sync Signal for CIC Stages
SYNC_RCF I/O Sync Signal for RCF
MODE I Sets Microport Mode: Mode 1, (MODE = 1), Mode 0, (MODE = 0)
A[2:0] I Microprocessor Interface Address
D[7.0] I/O/T Microprocessor Interface Data
DS or RD I Mode 1: Data Strobe Line, Mode 0: Read Signal
R/W or WR I Read/Write Line (Write Signal)

CS I Chip Select, Enables the Chip for µP Access
DTACK or RDY O Acknowledgment of a Completed Transaction (Signals when µP Port Is Ready for an Access)

PAR/SER I Parallel/Serial Control Select (PAR = 1, SER = 0)
DV

OUT

A/B

OUT

I/Q

OUT

TRST I Test Reset Pin
TCK I Test Clock Input
TMS I Test Mode Select Input
TDI I Test Data Input
TDO I Test Data Output

Pin Types: I = Input, O = Output, P = Power Supply, G = Ground, T = Three-state.

O Data Valid Pin for the Parallel Output Data
O Signals to Which Channel the Output Belongs to (A = 1, B = 0)
O Signals Whether I or Q Data Is Present (I = 1, Q = 0)

SHARED PINS

Parallel Outputs (PAR/SER = 1 at RESET) Serial Port (PAR/SER = 0 at RESET)

Name Type Description Name Type Description

OUT15 O Parallel Output Data SCLK I/O Serial Clock Input (SBM =0)

Serial Clock Output (SBM = 1)
OUT14 O Parallel Output Data SDI I Serial Data Input
OUT13 O Parallel Output Data SDO O/T Serial Data Output
OUT12 O Parallel Output Data SDFS I/O Serial Data Frame Sync Input (SBM = 0)

Serial Data Frame Sync Output (SBM = 1)
OUT11 O Parallel Output Data SDFE O Serial Data Frame End
OUT10 O Parallel Output Data SBM I Serial Bus Master (Master = 1, Cascade = 0)
OUT9 O Parallel Output Data WL1 I Serial Port Word Length, Bit 1
OUT8 O Parallel Output Data WL0 I Serial Port Word Length, Bit 0
OUT7 O Parallel Output Data AD I Append Data
OUT[6:4] O Parallel Output Data NC NC Unused, Do Not Connect
OUT3 O Parallel Output Data SDIV3 I SCLK Divide Value, Bit 3
OUT2 O Parallel Output Data SDIV2 I SCLK Divide Value, Bit 2
OUT1 O Parallel Output Data SDIV1 I SCLK Divide Value, Bit 1
OUT0 O Parallel Output Data (LSB) SDIV0 I SCLK Divide Value, Bit 0

Pin Types: I = Input, O = Output, P = Power Supply, G = Ground, T = Three-state.

–12–

REV. A

PIN CONFIGURATIONS

Parallel Output Data

AD6620

D6

D5

D4

VSS

D3

D2

D1

VDD

D0

DS

DTACK

R/W

VSS

MODE

A2

A1

A0

CS

EXP0

EXP1

OUT14

(MSB) OUT15

D7

80 79 78 77 76 71 70 69 68 67 66 6575 74 73 72 64 63 62 61

1

PIN 1

2

IDENTIFIER

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

IN14

EXP2

VDD

VSS

OUT12

OUT13

IN13

IN12

OUT11

IN11

OUT8

OUT9

OUT10

VSS

AD6620

TOP VIEW

(Not to Scale)

IN8

IN9

IN10

VDD

OUT7

IN7

VDD

VSS

OUT6

IN6

OUT5

IN5

OUT4

IN4

IN15 (MSB)

Serial Port

VSS

VDD

OUT3

IN3

OUT2

IN2

OUT1

IN1

60

OUT0 (LSB)

59

A/B

58

I/Q

57

VDD

56

DV

55

PAR/SER

54

RESET

53

TRST

52

TCK

51

TMS

50

TDO

49

TDI

48

VDD

47

SYNC

46

SYNC

45

SYNC

44

VSS

43

CLK
A/B

42

41

IN0 (LSB)

OUT

OUT

OUT

NCO

CIC
RCF

1

D6

2

D5

3

D4

4

VSS

5

D3

6

D2

7

D1

8

VDD

9

D0

10

DS

11

DTACK

12

R/W

13

VSS

14

MODE

15

A2

16

A1

17

A0

18

CS

19

EXP0

20

EXP1

NC = NO CONNECT

SCLK

D7

80 79 78 77 76 71 70 69 68 67 66 6575 74 73 72 64 63 62 61

PIN 1
IDENTIFIER

SDI

VDD

SDO

SDFS

SDFE

VSS

SBM

WL1

WL0

AD

VDD

NC

NC

NC

VSS

SDIV3

SDIV2

AD6620

TOP VIEW

(Not to Scale)

21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

IN4

EXP2

IN15

IN14

VSS

IN13

IN12

IN11

VDD

IN10

IN9

VSS

IN5

IN6

IN7

IN8

THE HIGHEST NUMBERED BIT IS THE MSB FOR ALL PORTS

VDD

IN3

IN2

SDIV1

60

59

58

57

56

55

54

53

52

51

50

49

48

47

46

45

44

43

42

41

IN1

SDIV0

A/B

OUT

I/Q

OUT

VDD
DV

OUT

PAR/SER

RESET
TRST

TCK

TMS

TDO

TDI

VDD

SYNC

SYNC
SYNC

VSS

CLK
A/B

IN0

NCO

CIC
RCF

–13–REV. A

AD6620

–Typical Performance Characteristics

400

375

350

325

300

POWER – mW

275

250

225

CIC2 DECIMATION

RCF DECIMATION

CIC5 DECIMATION

234

LOG

(M)

TPC 1. Typical Power vs. Decimation Rates

–12

–24

–36

–48

–60

–72

–84

–96

–108

–120

–132

0

0

SPUR = –104dB
PHASE DITHER OFF

TPC 2. Typical NCO Spur Without Dither

0

–20

–40

–60

–80

REJECTION – dB

–100

–120

51

–140

0

COMPOSITE FREQUENCY RESPONSE – MHz

1

23

TPC 4. High Decimation GSM Filter

Input sample rate 65 MSPS, decimation is 240, FIR taps is 240.
Unshown spectrum is below that shown. Decimation distribu­tion is 3, 10, 8, respectively.

0

–20

–40

–60

–80

REJECTION – dB

f

SAMP

–100

–120

–12

–24

–36

–48

–60

–72

–84

–96

–108

–120

–132

0

0

SPUR = –118dB
PHASE DITHER ON

TPC 3. Typical NCO Spur with Dither

f

SAMP

–140

0

2

COMPOSITE FREQUENCY RESPONSE – MHz

486

TPC 5. High Decimation AMPS Filter

Input sample rate 58.32 MSPS, decimation is 300, FIR taps is

128. Unshown spectrum is below that shown. Decimation distri­bution among CIC2, CIC5, and RCF is 10, 30 and 1, respectively.

–14–

REV. A