AD ADN2865ACP

Continuous Rate 12.3Mb/s to 2.7Gb/s
Clock and Data Recovery IC w/Loop Timed SERDES
ADN2865
Preliminary Technical Data
FEATURES
PRODUCT DESCRIPTION
Serial data input: 12.3 Mb/s to 2.7 Gb/s
Exceeds ITU-T Jitter Specifications
Integrated Limiting Amp: 6mV sensitivity
Adjustable slice level: ±100 mV
Patented dual-loop clock recovery architecture
Programmable LOS detect and Slice Level
Integrated PRBS Generator and Detector
No reference clock required
Loss of lock indicator
Rate Selectivity without the use of a reference clock
I2C™ interface to access optional features
Single-supply operation: 3.3 V
Low power: 1.0W
8 mm × 8 mm 56-lead LFCSP
The ADN2865 provides the receiver functions of quantization,
signal level detect, and clock and data recovery for continuous
data rates from 12.3 Mb/s to 2.7 Gb/s. An integrated
deserialiser supports 8 bit parallel transfer to an FPGA or digital
ASIC. The recovered clock can simultaneously serialize data
supplied in an 8 bit parallel format.
APPLICATIONS
Passive Optical Network s
SONET OC-1/3/12/48 and all associated FEC rates
Fibre Channel, 2× Fibre Channel , GbE, HDTV, etc.
WDM transponders
Test equipment
The ADN2865 automatically locks to all data rates without the
need for an external reference clock or programming. All
SONET jitter requirements are exceeded, including jitter
transfer, jitter generation, and jitter tolerance. All specifications
are quoted for −40°C to +85°C ambient temperature, unless
otherwise noted.
This device, together with a PIN diode and a TIA preamplifier,
can implement a highly integrated, low cost, low power fiber
optic receiver.
The ADN2865 have many optional features available via an I2C
interface, e.g. the user can read back the data rate that the
ADN2865 is locked on to, or the user can set the device to only
lock to one particular data rate if provisioning of data rates is
required.
FUNCTIONAL BLOCK DIAGRAM
Figure 1 ADN2865 Functional Block Diagram
Rev.PrA
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.326.8703
© 2006 Analog Devices, Inc. All rights reserved.
ADN2865
Preliminary Technical Data
TABLE OF CONTENTS
Specifications..................................................................................... 3
Functional Description.................................................................. 20
Jitter Specifications....................................................................... 4
Frequency Acquisition............................................................... 20
Output and Timing Specifications ............................................. 5
Limiting Amplifier ..................................................................... 21
Absolute Maximum Ratings............................................................ 6
Slice Adjust.................................................................................. 22
Thermal Characteristics .............................................................. 7
Loss of Signal (LOS) Detector .................................................. 22
ESD Caution.................................................................................. 7
Lock Detector Operation .......................................................... 20
Timing Characteristics..................................................................... 9
Harmonic Detector .................................................................... 21
Pin Configuration and Function Descriptions........................... 10
Squelch Mode .......................... Error! Bookmark not defined.
Typical Performance Characteristics ............................................. 8
I2C Interface ............................................................................... 22
I2C Interface Timing and Internal Register Description........... 12
Reference Clock (Optional) ...................................................... 23
Terminology .................................................................................... 16
Applications Information .............................................................. 26
Jitter Specifications ......................................................................... 17
PCB Design Guidelines ............................................................. 26
Jitter Generation ......................................................................... 17
DC-Coupled Application .......................................................... 28
Jitter Transfer............................................................................... 17
Coarse Data Rate Readback Look-Up Table............................... 30
Jitter Tolerance ............................................................................ 17
Outline Dimensions ....................................................................... 32
Theory of Operation ...................................................................... 18
Ordering Guide .......................................................................... 32
REVISION HISTORY
Revision 0: Initial Version
Revision A: Remove Minimum Supply Current Spec
Revision B: Update spec table
Rev. PrA | Page 2 of 33
Preliminary Technical Data
ADN2865
SPECIFICATIONS
TA = TMIN to TMAX, VCC = VMIN to VMAX, VEE = 0 V, CF = 0.47 μF, SLICEP = SLICEN = VEE, Input Data Pattern: PRBS 223 − 1,
unless otherwise noted.
Table 1.
Parameter
QUANTIZER—DC CHARACTERISTICS
Input Voltage Range
Peak-to-Peak Differential Input
Input Common Mode Level
Differential Input Sensitivity
Input Overdrive
Input Offset
Input RMS Noise
QUANTIZER—AC CHARACTERISTICS
Data Rate
S11
Input Resistance
Input Capacitance
QUANTIZER—SLICE ADJUSTMENT
Gain
Differential Control Voltage Input
Control Voltage Range
Slice Threshold Offset
LOSS OF SIGNAL DETECT (LOS)
Loss of Signal Detect Range (see Figure 2)
Hysteresis (Electrical)
LOS Assert Time
LOS De-Assert Time
LOSS OF LOCK DETECT (LOL)
VCO Frequency Error for LOL Assert
VCO Frequency Error for LOL De-Assert
LOL Response Time
ACQUISITION TIME
Lock to Data Mode
Conditions
Min
@ PIN or NIN, dc-coupled
PIN – NIN
DC-coupled (see Figure , Figure , and
Figure )
223 − 1 PRBS, ac-coupled,1 BER = 1 x 10–10
(see Figure )
1.8
2
2.3
2.5
TBD
TBD
TBD
TBD
TBD
TBD
BER = 1 x 10–10
12.3
Max
Unit
2.8
2.0
2.8
V
V
V
mV p-p
mV p-p
μV
μV rms
2700
Mb/s
dB
Ω
pF
TBD
TBD
0.95
V/V
V
V
mV
TBD
TBD
TBD
TBD
mV
mV
TBD
TBD
TBD
TBD
dB
dB
TBD
TBD
TBD
TBD
TBD
TBD
dB
dB
ns
ns
With respect to nominal
With respect to nominal
12.3 Mb/s
OC-12
OC-48
1000
250
4
1.0
1.0
ppm
ppm
ms
μs
μs
OC-48
OC-12
OC-3
OC-1
12.3 Mb/s
1.3
2.0
3.4
9.8
40.0
10.0
ms
ms
ms
ms
ms
ms
@ 2.5 GHz
Differential
SLICEP – SLICEN = ±0.5 V
SLICEP – SLICEN
DC level @ SLICEP or SLICEN
−15
100
0.65
TBD
0.1
VEE
1
RThresh = 0 Ω
RThresh = 100 kΩ
OC-48
RThresh = 0 Ω
RThresh = 100 kΩ
OC-1
RThresh = 0 Ω
RThresh = 10 kΩ
DC-coupled2
DC-coupled2
Optional Lock to REFCLK Mode
1
Typ
PIN and NIN should be differentially driven and ac-coupled for optimum sensitivity.
When ac-coupled, the LOS assert and de-assert time is dominated by the RC time constant of the ac coupling capacitor and the 50 Ω input termination of the
ADN2865 input stage.
Rev. PrA | Page 3 of 33
ADN2865
Parameter
DATA RATE READBACK ACCURACY
Coarse Readback
Fine Readback
Preliminary Technical Data
Conditions
Min
(See Table )
In addition to REFCLK accuracy
Data rate < 20 Mb/s
Data rate > 20 Mb/s
POWER SUPPLY VOLTAGE
POWER SUPPLY CURRENT
OPERATING TEMPERATURE RANGE
Typ
Max
10
3.0
3.3
300
–40
Unit
%
200
100
3.6
350
+85
ppm
ppm
V
mA
°C
JITTER SPECIFICATIONS
TA = TMIN to TMAX, VCC = VMIN to VMAX, VEE = 0 V, CF = 0.47 uF, SLICEP = SLICEN = VEE, Input Data Pattern: PRBS 223 − 1,
unless otherwise noted.
Table 2.
Parameter
PHASE-LOCKED LOOP CHARACTERISTICS
Jitter Transfer BW
Jitter Peaking
Jitter Generation
Conditions
Min
OC-48
OC-12
OC-3
OC-48
OC-12
OC-3
OC-48, 12 kHz to 20 MHz
OC-12, 12 kHz to 5 MHz
OC-3, 12 kHz to 1.3 MHz
Jitter Tolerance
Power Supply Rejection
OC-48, 223 − 1 PRBS
100 kHz
1 MHz
20 MHz
OC-12, 223 − 1 PRBS
25 kHz
250 kHzError! Bookmark not defined.
OC-3, 223 − 1 PRBS
6500 Hz
65 kHz
See Figure XX.
Rev. PrA | Page 4 of 33
Typ
Max
Unit
0
0
0
TBD
TBD
TBD
TBD
TBD
TBD
2000
500
130
0.1
0.1
0.1
TBD
0.33
TBD
0.2
TBD
0.2
kHz
kHz
kHz
dB
dB
dB
UI rms
UI p-p
UI rms
UI p-p
UI rms
UI p-p
0.75
0.075
0.075
UI p-p
UI p-p
UI p-p
0.75
0.075
UI p-p
UI p-p
0.75
0.075
UI p-p
UI p-p
dB
TBD
Preliminary Technical Data
ADN2865
OUTPUT AND TIMING SPECIFICATIONS
Table 3.
Parameter
CML OUPUT CHARACTERISTICS
Single-Ended Output Swing
Differential Output Swing
Output High Voltage
Output Low Voltage
CML Ouput Timing
Rise Time
Fall Time
LVDS OUPUT CHARACTERISTICS
(RXCLKP/N, RXDATP/N)
Differential Output Swing
Output High Voltage
Output Low Voltage
Output Offset Voltage
Output Impedance
LVDS Ouputs Timing
Rise Time
Fall Time
Setup Time
Hold Time
I2C INTERFACE DC CHARACTERISTICS
Input High Voltage
Input Low Voltage
Input Current
Output Low Voltage
I2C INTERFACE TIMING
SCK Clock Frequency
SCK Pulse Width High
SCK Pulse Width Low
Start Condition Hold Time
Start Condition Setup Time
Data Setup Time
Data Hold Time
SCK/SDA Rise/Fall Time
Stop Condition Setup Time
Bus Free Time between a Stop and a Start
REFCLK CHARACTERISTICS
Input Voltage Range
Minimum Differential Input Drive
Reference Frequency
Required Accuracy
LVTTL DC INPUT CHARACTERISTICS
Input High Voltage
Input Low Voltage
Input High Current
1
Conditions
Min
Typ
Max
Unit
VSE (see Figure 75)
VDIFF (see Figure 75)
VOH
VOL
300
600
350
700
VCC − 0.6
VCC − 0.35
600
1200
VCC
VCC − 0.3
mV
mV
V
V
TBD
TBD
ps
ps
320
400
1475
1200
100
1275
mV
mV
V
V
Ω
115
115
220
220
20% to 80%
80% to 20%
VDIFF (see Figure 4)
VOH
VOL
VOS
Differential
20% to 80%
80% to 20%
TS (see Figure 4), OC-48
TH (see Figure 4), OC-48
LVCMOS
VIH
VIL
VIN = 0.1 VCC or VIN = 0.9 VCC
VOL, IOL = 3.0 mA
(See Figure )
250
925
1125
2.61
-1.70
0.7 VCC
0.3 VCC
+10.0
0.4
−10.0
400
tHIGH
tLOW
tHD;STA
tSU;STA
tSU;DAT
tHD;DAT
TR/TF
tSU;STO
tBUF
Optional lock to REFCLK mode
@ REFCLKP or REFCLKN
VIL
VIH
600
1300
600
600
100
300
20 + 0.1 Cb1
600
1300
300
0
VCC
100
12.3
200
100
VIH
VIL
IIH, VIN = 2.4 V
2.0
Cb = total capacitance of one bus line in pF. If mixed with Hs-mode devices, faster fall-times are allowed (see Table 6).
Rev. PrA | Page 5 of 33
0.8
5
ps
ps
ns
ns
V
V
μA
V
kHz
ns
ns
ns
ns
ns
ns
ns
ns
ns
V
V
mV p-p
MHz
ppm
V
V
μA
ADN2865
Parameter
Input Low Current
LVTTL INPUT TIMING
Setup Time (Sync Mode)
Hold Time (Sync Mode)
Setup Time (Align Mode)
Hold Time (Align Mode)
LVTTL DC OUTPUT CHARACTERISTICS
Output High Voltage
Output Low Voltage
Preliminary Technical Data
Conditions
IIL, VIN = 0.4 V
Min
−5
TSSU (see Figure 3), 1.25Gb/s
TSH (see Figure 3), 1.25Gb/s
TASU (see Figure 4), 1.25Gb/s
TAH (see Figure 4), 1.25Gb/s
3.60
0.70
TBD
TBD
VOH, IOH = −2.0 mA
VOL, IOL = 2.0 mA
2.4
Rev. PrA | Page 6 of 33
Typ
Max
Unit
μA
ns
ns
ns
ns
0.4
V
V
Preliminary Technical Data
ADN2865
ABSOLUTE MAXIMUM RATINGS
TA = TMIN to TMAX, VCC = VMIN to VMAX, VEE = 0 V, CF = 0.47
μF, SLICEP = SLICEN = VEE, unless otherwise noted.
Table 4.
Parameter
Supply Voltage (VCC)
Minimum Input Voltage (All Inputs)
Maximum Input Voltage (All Inputs)
Maximum Junction Temperature
Storage Temperature
Lead Temperature (Soldering 10 s)
Rating
4.2 V
VEE − 0.4 V
VCC + 0.4 V
125°C
−65°C to +150°C
300°C
Stress above those listed under Absolute Maximum Ratings may
cause permanent damage to the device. This is a stress rating
only and functional operation of the device at these or any other
conditions above 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
Thermal Resistance
56-LFCSP, 4-layer board with exposed paddle soldered to VEE
θJA = 28°C/W
ESD 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 this product 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.
Rev. PrA | Page 7 of 33
ADN2865
Preliminary Technical Data
TYPICAL PERFORMANCE CHARACTERISTICS
1000
16
ADN2812 TOLERANCE
SONET REQUIREMENT MASK
SONET OBJECTIVE MASK
EQUIPMENT LIMIT
10
8
6
4
2
1
10
100
1k
10k
100
10
1
04228-0-030
JITTER AMPLITUDE (UI)
12
04228-0-003
TRIP POINT (mV p-p)
14
0.1
1
100k
RTH (Ω)
Figure 2. LOS Comparator Trip Point Programming
10
100
1k
10k
100k
1M
JITTER FREQUENCY (Hz)
10M
Figure 3. Typical Measured Jitter Tolerance OC-48
Rev. PrA | Page 8 of 33
100M
Preliminary Technical Data
ADN2865
TIMING CHARACTERISTICS
Figure 4. Rx Output Timing
RXCLKP/ N
Tssu
Tsh
TXDATAP / N[ 7:0]
04228-0-002
Figure 5. Tx Input Timing (Sync Mode)
Figure 6. Tx Input Timing Align Mode)
OUTP
VCML
VSE
OUTN
OUTP–OUTN
VDIFF
04228-0-004
VSE
0V
Figure 75. Single-Ended vs. Differential Output Specifications
Rev. PrA | Page 9 of 33
TXDAT4
TXCLK
TXDAT3
TXDAT2
TXDAT1
TXDAT0
VREG
CF1
VEE
VCC
VEE
VCC
REFN
REFP
15
16
17
18
19
20
21
22
23
24
25
26
27
28
56
55
54
53
52
51
50
49
48
47
46
45
44
43
RXDATP2
RXDATN2
RXDATP3
RXDATN3
RXDATP4
RXDATN4
VCC
RXDATP5
RXDATN5
RXDATP6
RXDATN6
VCC
RXDATP7
RXDATN7
ADN2865
Preliminary Technical Data
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Figure 86. Pin Configuration
Rev. PrA | Page 10 of 33
Preliminary Technical Data
ADN2865
Table 5. Pin Function Descriptions
Pin #
Mnemonic
Type
Description
1
SDOUT
DO
Active high, Loss of signal indicator. (LVTTL)
2
RXDATN1
DO
Differential receive data output. (LVDS)
3
RXDATP1
DO
4
RXDATN0
DO
Differential receive data output. (LVDS)
Differential receive data output. Last bit received. (LVDS)
5
RXDATP0
DO
Differential receive data output. Last bit received. (LVDS)
6
VCC3
PWR
Power for CDR & Serialiser
7
VCC7
PWR
Power for CML drivers
8
SERDATN
DO
Differential serialized data output to LDD. (CML)
9
SERDATP
DO
Differential serialized data output to LDD. (CML)
10
SERCLKN
DO
Differential clock for serialized Tx data. (CML)
11
SERCLKP
DO
12
TXDAT7
DI
Differential clock for serialized Tx data. (CML)
Transmit data input. First bit sent. (LVTTL)
13
TXDAT6
DI
Transmit data input. (LVTTL)
14
TXDAT5
DI
Transmit data input. (LVTTL)
15
TXDAT4
DI
Transmit data input. (LVTTL)
16
TXCLK
DI
Qualifying clock for transmit data input. (LVTTL)
17
TXDAT3
DI
Transmit data input. (LVTTL)
18
TXDAT2
DI
Transmit data input. (LVTTL)
19
TXDAT1
DI
20
TXDAT0
DI
Transmit data input. (LVTTL)
Transmit data input. Last bit sent. (LVTTL)
21
VREG
AO
Decoupling node for VCO power.
22
CF1
AO
PLL loop filter capacitor.
23
VEE2
PWR
Ground for VCO / PLL / Gm
24
VCC2
PWR
Power for VCO / PLL / Gm
25
VEE4
PWR
Ground for FLL
26
VCC4
PWR
Power for FLL
27
REFN
DI
Reference clock input. (LVDS/LVTTL)
28
REFP
DI
Reference clock input. (LVDS/LVTTL)
29
THRADJ
AO
LOS Threshold Setting Resistor.
30
LOL
DO
Active high, Loss-of-Lock Indicator. (LVTTL)
31
VEE1
PWR
Ground for Limamp / LOS
32
SLICEN
AI
Differential Slice Level Adjust Input.
33
SLICEP
AI
Differential Slice Level Adjust Input.
34
NIN
AI
Differential serial input to Limiting Amp. (CML)
35
PIN
AI
Differential serial input to Limiting Amp. (CML)
36
VREF
AO
Decoupling node for internal voltage reference.
37
VCC1
PWR
Power for Limamp / LOS
38
SCK
DI
I2C Serial Clock Input.
39
VCC6
PWR
Power for Deserialiser, LVDS pre-drivers
40
SDA
DI
I2C Serial Data Input.
41
RXCLKN
DO
Qualifying clock for Rx Data Outputs. (LVDS)
42
RXCLKP
DO
43
RXDATN7
DO
Qualifying clock for Rx Data Outputs. (LVDS)
Differential receive data output. Last bit received. (LVDS)
44
RXDATP7
DO
Differential receive data output. Last bit received. (LVDS)
45
VCC5
PWR
Power for LVDS drivers
46
RXDATN6
DO
Differential receive data output. (LVDS)
47
RXDATP6
DO
Differential receive data output. (LVDS)
48
RXDATN5
DO
Differential receive data output. (LVDS)
49
RXDATP5
DO
Differential receive data output. (LVDS)
50
VCC5
PWR
Power for LVDS Drivers
51
RXDATN4
DO
Differential receive data output. (LVDS)
52
RXDATP4
DO
Differential receive data output. (LVDS)
53
RXDATN3
DO
Differential receive data output. (LVDS)
54
RXDATP3
DO
Differential receive data output. (LVDS)
55
RXDATN2
DO
Differential receive data output. (LVDS)
56
RXDATP2
DO
Differential receive data output. (LVDS)
1
Type: P = power, AI = analog input, AO = analog output, DI = digital input, DO = digital output.
Rev. PrA | Page 11 of 33
ADN2865
Preliminary Technical Data
I2C INTERFACE TIMING AND INTERNAL REGISTER DESCRIPTION
R/W
CTRL.
SLAVE ADDRESS [6...0]
1
1
0
0
0
0
0
X
0 = WR
1 = RD
MSB = 1
S
SLAVE ADDR, LSB = 0 (WR) A(S) SUB ADDR A(S) DATA A(S)
DATA A(S)
P
04228-0-006
Figure 9. Slave Address Configuration
S
SLAVE ADDR, LSB = 0 (WR) A(S) SUB ADDR A(S) S SLAVE ADDR, LSB = 1 (RD) A(S) DATA A(M)
S = START BIT
A(S) = ACKNOWLEDGE BY SLAVE
DATA A(M) P
P = STOP BIT
A(M) = LACK OF ACKNOWLEDGE BY MASTER
A(M) = ACKNOWLEDGE BY MASTER
04228-0-007
Figure 10. I2C Write Data Transfer
Figure 11. I2C Read Data Transfer
SDA
SLAVE ADDRESS
A6
SUB ADDRESS
A5
STOP BIT
DATA
A7
A0
D7
D0
SCK
S
WR
ACK
ACK
SLADDR[4...0]
ACK
SUB ADDR[6...1]
DATA[6...1]
Figure 12. I2C Data Transfer Timing
tF
tSU;DAT
tHD;STA
tBUF
SDA
tR
tR
tSU;STO
tF
tLOW
tHIGH
tHD;STA
S
tSU;STA
S
tHD;DAT
Figure 13. I2C Port Timing Diagram
Rev. PrA | Page 12 of 33
P
S
04228-0-009
SCK
P
04228-0-008
START BIT
Preliminary Technical Data
ADN2865
Table 6. Internal Register Map1
Reg Name
R/W
ADDRES
S
D7
FREQ0
R
0x0
MSB
LSB
FREQ1
R
0x1
MSB
LSB
FREQ2
R
0x2
0
RATE
R
0x3
MISC
R
0x4
CTRLA
W
0x8
CTRLA_R
D
R
0x5
CTRLB
W
0x9
CTRLB_R
D
R
0x6
CTRLC
W
0x11
0
0
Set Signal
Degrade
Threshold
Enable
Signal
Degrade
LOS forces
acquisition
CTRLD
W
0x22
CDR Bypass
Power
Down
LVDS
Drivers
Power
Down CML
Drivers
Squelch
Output
Buffers
Initiate PBS
Sequence
CTRLE
W
0x27
Align
TX Mode
FDDI_MO
DE
W
0x0D
FDDI Mode
Enable
SEL_MOD
E
W
0x34
0
HI_CODE
W
0x35
HI_CODE[8]
HI_CODE[1]
LO_CODE
W
0x36
LO_CODE[8]
LO_CODE[1]
CODE_LSB
W
0x39
1
D6
D5
D4
D3
D2
D1
D0
MSB
LSB
COARSE_RD[8]
Coarse Data Readback
X
X
Los Status
Fref Range
Static LOL
LOL Status
COARSE_RD[1]
Datarate
meas
complete
X
COARSE_RD[
0] LSB
Measure
Data Rate
Lock to
Reference
0
0
0
Config LOS
Squelch
Mode
Boost Output
Data Rate/DIV FREF Ratio
Readback CTRLA
Config LOL
Reset
MISC[4]
System
Reset
0
Reset
MISC[2]
Readback CTRLB
RXCLK Alignment
0
PRBS Mode[2:0]
Reverse RX
Bus
Reverse TX
Bus
0
0
0
CLK
Holdover
Mode 2B
0
Subharmonic Ratio
0
0
Acq Mode
Cont Rate /
Single Rate
0
0
Datarate
Range
0
CLK
Holdover
Mode 2A
0
HI_CODE[0]
LO_CODE[0]
All writeable registers default to 0x00.
Table 7. Miscellaneous Register, MISC
D7
x
D6
x
LOS Status
D5
0 = No loss of signal
1 = Loss of signal
Static LOL
D4
0 = Waiting for next LOL
1 = Static LOL until reset
LOL Status
D3
0 = Locked
1 = Acquiring
Rev. PrA | Page 13 of 33
Datarate Measurement
Complete
D2
0 = Measuring datarate
1 = Measurement complete
D1
x
Coarse Rate
Readback LSB
D0
COARSE_RD[0]
ADN2865
Preliminary Technical Data
Table 8. Control Register, CTRLA1
FREF Range
D7 D6
0
0
0
1
1
0
1
1
1
12.3 MHz to 25 MHz
25 MHz to 50 MHz
50 MHz to 100 MHz
100 MHz to 200 MHz
Datarate/Div_FREF Ratio
D5 D4 D3 D2
0
0
0
0
0
0
0
1
0
0
1
0
n
1
0
0
0
Measure Datarate
D1
Set to 1 to measure datarate
1
2
4
2n
256
Lock to Reference
D0
0 = Lock to input data
1 = Lock to reference clock
Where DIV_FREF is the divided down reference referred to the 12.3 MHz to 25 MHz band (see the Reference Clock (Optional) section).
Table 9. Control Register, CTRLB
Config LOL
D7
0 = LOL pin normal operation
1 = LOL pin is static LOL
Reset MISC[4]
D6
Write a 1 followed by
0 to reset MISC[4]
System Reset
D5
Write a 1 followed by
0 to reset ADN2865
D4
Set
to 0
Reset MISC[2]
D3
Write a 1 followed by
0 to reset MISC[2]
D2
Set
to 0
D1
Set
to 0
D0
Set
to 0
Table 10. Control Register, CTRLC
D7
Set
to 0
D6
Set
to 0
Signal Degrade Threshold
D5
0=Set SD Threshold to 9mV
1=Set SD Threshold to 1.9x
LOS Threshold
Signal Degrade Mode
D4
0= Disable Signal Degrade
Mode
1= Enable Signal Degrade
Mode
D3
Set
to 0
Config LOS
D2
0 = Active high LOS
1 = Active low LOS
SERCLK
D1
0 = Power Down
SERCLK buffer
1 = Enable SERCLK
buffer
D0
Set
to 0
Table 11. Control Register, CTRLD
CDR Bypass
D7
0=CDR Enabled
1=CDR Disabled
Buffer Control
D6
0=Normal
operation
1=Power Down
LVDS drivers
D5
0=Normal
operation
1=Power Down
CML drivers
D4
0
Initiate PRBS
D3
Write a 1 followed by 0
to initiate PRBS
Generate Sequence
D2
0
0
0
D1
0
0
1
PRBS Mode
D0
0
Power Down
Generate Mode
1
Detect Mode,
0
compares errors
Table 12. Control Register, CTRLE
RXCLK Alignment to RXDATA
D7
D6
D5
0
0
0
0
+1 UI
1
0
0
0
0
1
0
-3 UI
1
1
0
+4 UI
0
0
1
+2 UI
1
0
1
+4 UI
0
1
1
-2 UI
1
1
1
Tx Mode
D4
0=Sync Mode
1=Align
D3
0=Enable align
1=Disable align
Rev. PrA | Page 14 of 33
Bus Reversal
D2
RXDATA[7:0]
0=Bit 0 is last received
1=Bit 7 is last received
D1
TXDATA[7:0]
0=Bit 0 is last sent
1=Bit 7 is last sent
D0
Set
To 0
Preliminary Technical Data
ADN2865
Table 13. FDDI_MODE
FDDI Enable
D7
0= FDDI Mode Disabled
1= FDDI Mode Enabled
Subharmonic Ratio [6..2]
D6 D5 D4
D3
D2
0
0
0
0
1
0
0
0
1
0
0
0
0
1
1
--------------------1
1
1
1
1
= 1
= 2
= 3
D1
Set to 0
D0
Set to 0
= 31
Table 14. SEL_MODE
D7
Set
to 0
D6
Set
to 0
Mode Control 2
D5
0=LTD/LTR Mode
1=LTR Mode Only
Mode Control 1
D4
0= Continuous Rate
1= Single Rate
Mode Control 0
D3
0= Full Range (12.3M2.7G)
1= Limited Range
Clock Holdover
Mode 2A
D2
Set to 1 for Clock
Holdover Mode 2A
Clock Holdover
Mode 2B
D1
Set to 1 for Clock
Holdover Mode 2B
D0
Set
to 0
Table 15. CTLF
D7
Set to 0
D6
Set to 0
D5
Set to 0
D4
Set to 0
D3
Set to 0
Rev. PrA | Page 15 of 33
CDR Mode
D2 D1 D0
0 0 0 = NDC -> OB
1 0 1 = NDC -> PRBS
ADN2865
Preliminary Technical Data
TERMINOLOGY
10mVp-p
Input Sensitivity and Input Overdrive
VREF
Sensitivity and overdrive specifications for the quantizer involve
offset voltage, gain, and noise. The relationship between the
logic output of the quantizer and the analog voltage input is
shown in Figure . For sufficiently large positive input voltage,
the output is always Logic 1 and, similarly for negative inputs,
the output is always Logic 0. However, the transitions between
output Logic Levels 1 and 0 are not at precisely defined input
voltage levels, but occur over a range of input voltages. Within
this range of input voltages, the output might be either 1 or 0, or
it might even fail to attain a valid logic state. The width of this
zone is determined by the input voltage noise of the quantizer.
The center of the zone is the quantizer input offset voltage.
Input overdrive is the magnitude of signal required to guarantee
the correct logic level with 1 × 10−10 confidence level.
OUTPUT
0
OFFSET
PIN
+
Quantizer
50
50
VREF
2.5V
3k
Figure 15. Single-Ended Sensitivity Measurement
Driving the ADN2865 differentially (see Figure ), sensitivity
seems to improve from observing the quantizer input with an
oscilloscope probe. This is an illusion caused by the use of a
single-ended probe. A 5 mV p-p signal appears to drive the
ADN2865 quantizer. However, the single-ended probe
measures only half the signal. The true quantizer input signal is
twice this value, because the other quantizer input is a complementary signal to the signal being observed.
NOISE
1
scope
probe
INPUT (V p-p)
5mV p-p
SCOPE
PROBE
OVERDRIVE
04228-0-010
SENSITIVITY
(2× OVERDRIVE)
VREF
PIN
Figure 14. Input Sensitivity and Input Overdrive
+
QUANTIZER
NIN
AC coupling is typically used to drive the inputs to the
quantizer. The inputs are internally dc biased to a commonmode potential of ~2.5 V. Driving the ADN2865 single-ended
and observing the quantizer input with an oscilloscope probe at
the point indicated in Figure shows a binary signal with an
average value equal to the common-mode potential and
instantaneous values both above and below the average value. It
is convenient to measure the peak-to-peak amplitude of this
signal and call the minimum required value the quantizer
sensitivity. Referring to Figure , because both positive and
negative offsets need to be accommodated, the sensitivity is
twice the overdrive. The ADN2865 quantizer typically has
6 mV p-p sensitivity.
–
50Ω
VREF
50Ω
VREF
5mV p-p
2.5V
3kΩ
04228-0-012
Single-Ended vs. Differential
Figure 16. Differential Sensitivity Measurement
LOS Response Time
LOS response time is the delay between removal of the input
signal and indication of loss of signal (LOS) at the LOS output,
Pin 22. When the inputs are dc-coupled, the LOS assert time of
the AD2817 is 500 ns typically and the de-assert time is 400 ns
typically,. In practice, the time constant produced by the ac
coupling at the quantizer input and the 50 Ω on-chip input
termination determines the LOS response time.
Rev. PrA | Page 16 of 33
Preliminary Technical Data
ADN2865
JITTER SPECIFICATIONS
JITTER GENERATION
The jitter generation specification limits the amount of jitter
that can be generated by the device with no jitter and wander
applied at the input. For OC-48 devices, the band-pass filter
has a 12 kHz high-pass cutoff frequency with a roll-off of
20 dB/decade, and a low-pass cutoff frequency of at least
20 MHz. The jitter generated must be less than 0.01 UI rms, and
must be less than 0.1 UI p-p.
JITTER TRANSFER
The jitter transfer function is the ratio of the jitter on the output
signal to the jitter applied on the input signal versus the
frequency. This parameter measures the limited amount of the
jitter on an input signal that can be transferred to the output
signal (see Figure ).
SLOPE = –20dB/DECADE
04228-0-013
ACCEPTABLE
RANGE
fC
JITTER FREQUENCY (kHz)
Figure 17. Jitter Transfer Curve
JITTER TOLERANCE
The jitter tolerance is defined as the peak-to-peak amplitude of
the sinusoidal jitter applied on the input signal, which causes a
1 dB power penalty. This is a stress test intended to ensure that
no additional penalty is incurred under the operating
conditions (see Figure ).
15.00
SLOPE = –20dB/DECADE
1.50
0.15
f0
f1
f2
f3
JITTER FREQUENCY (kHz)
Figure 18. SONET Jitter Tolerance Mask
Rev. PrA | Page 17 of 33
f4
04228-0-014
The following sections briefly summarize the specifications of
jitter generation, transfer, and tolerance in accordance with the
Telcordia document (GR-253-CORE, Issue 3, September 2000)
for the optical interface at the equipment level and the
ADN2865 performance with respect to those specifications.
JITTER GAIN (dB)
Jitter is the dynamic displacement of digital signal edges from
their long-term average positions, measured in unit intervals
(UI), where 1 UI = 1 bit period. Jitter on the input data can
cause dynamic phase errors on the recovered clock sampling
edge. Jitter on the recovered clock causes jitter on the
retimed data.
0.1
INPUT JITTER AMPLITUDE (UI p-p)
The ADN2865 CDR is designed to achieve the best bit-errorrate (BER) performance and exceeds the jitter transfer, generation, and tolerance specifications proposed for SONET/SDH
equipment defined in the Telcordia Technologies specification.
ADN2865
Preliminary Technical Data
THEORY OF OPERATION
Another view of the circuit is that the phase shifter implements
the zero required for frequency compensation of a second-order
phase-locked loop, and this zero is placed in the feedback path
and, thus, does not appear in the closed-loop transfer function.
Jitter peaking in a conventional second-order phase-locked loop
is caused by the presence of this zero in the closed-loop transfer
function. Because this circuit has no zero in the closed-loop
transfer, jitter peaking is minimized.
The delay- and phase-loops together simultaneously provide
wide-band jitter accommodation and narrow-band jitter
filtering. The linearized block diagram in Figure shows that the
jitter transfer function, Z(s)/X(s), is a second-order low-pass
providing excellent filtering. Note that the jitter transfer has no
zero, unlike an ordinary second-order phase-locked loop. This
means that the main PLL loop has virtually zero jitter peaking
(see Figure ). This makes this circuit ideal for signal regenerator
applications, where jitter peaking in a cascade of regenerators
can contribute to hazardous jitter accumulation.
The error transfer, e(s)/X(s), has the same high-pass form as an
ordinary phase-locked loop. This transfer function is free to be
optimized to give excellent wide-band jitter accommodation,
because the jitter transfer function, Z(s)/X(s), provides the
narrow-band jitter filtering.
INPUT
DATA
X(s)
e(s)
o/s
d/sc
1/n
Z(s)
RECOVERED
CLOCK
d = PHASE DETECTOR GAIN
o = VCO GAIN
c = LOOP INTEGRATOR
psh = PHASE SHIFTER GAIN
n = DIVIDE RATIO
JITTER TRANSFER FUNCTION
Z(s)
1
=
X(s)
n psh
cn
+1
+s
s2
o
do
04228-0-015
TRACKING ERROR TRANSFER FUNCTION
e(s)
s2
=
d psh do
X(s)
+
s2 + s
c
cn
Figure 19. ADN2865 PLL/DLL Architecture
JITTER PEAKING
IN ORDINARY PLL
ADN2812
Z(s)
X(s)
o
n psh
d psh
c
04228-0-016
The delay- and phase-loops together track the phase of the
input data signal. For example, when the clock lags input data,
the phase detector drives the VCO to higher frequency, and also
increases the delay through the phase shifter; both these actions
serve to reduce the phase error between the clock and data. The
faster clock picks up phase, while the delayed data loses phase.
Because the loop filter is an integrator, the static phase error is
driven to zero.
psh
JITTER GAIN (dB)
The ADN2865 is a delay- and phase-locked loop circuit for
clock recovery and data retiming from an NRZ encoded data
stream. The phase of the input data signal is tracked by two
separate feedback loops, which share a common control voltage.
A high speed delay-locked loop path uses a voltage controlled
phase shifter to track the high frequency components of input
jitter. A separate phase control loop, comprised of the VCO,
tracks the low frequency components of input jitter. The initial
frequency of the VCO is set by yet a third loop, which compares
the VCO frequency with the input data frequency and sets the
coarse tuning voltage. The jitter tracking phase-locked loop
controls the VCO by the fine-tuning control.
FREQUENCY (kHz)
Figure 20. ADN2865 Jitter Response vs. Conventional PLL
The delay- and phase-loops contribute to overall jitter accommodation. At low frequencies of input jitter on the data signal,
the integrator in the loop filter provides high gain to track large
jitter amplitudes with small phase error. In this case, the VCO is
frequency modulated and jitter is tracked as in an ordinary
phase-locked loop. The amount of low frequency jitter that can
be tracked is a function of the VCO tuning range. A wider
tuning range gives larger accommodation of low frequency
jitter. The internal loop control voltage remains small for small
phase errors, so the phase shifter remains close to the center of
its range and thus contributes little to the low frequency jitter
accommodation.
Rev. PrA | Page 18 of 33
Preliminary Technical Data
ADN2865
At medium jitter frequencies, the gain and tuning range of the
VCO are not large enough to track input jitter. In this case, the
VCO control voltage becomes large and saturates, and the VCO
frequency dwells at one extreme of its tuning range or the other.
The size of the VCO tuning range, therefore, has only a small
effect on the jitter accommodation. The delay-locked loop
control voltage is now larger, and so the phase shifter takes on
the burden of tracking the input jitter. The phase shifter range,
in UI, can be seen as a broad plateau on the jitter tolerance
curve. The phase shifter has a minimum range of 2 UI at all
data rates.
cannot be tolerated. In this region, the gain of the integrator
determines the jitter accommodation. Because the gain of the
loop integrator declines linearly with frequency, jitter accommodation is lower with higher jitter frequency. At the highest
frequencies, the loop gain is very small, and little tuning of the
phase shifter can be expected. In this case, jitter
accommodation is determined by the eye opening of the input
data, the static phase error, and the residual loop jitter
generation. The jitter accommodation is roughly 0.5 UI in this
region. The corner frequency between the declining slope and
the flat region is the closed loop bandwidth of the delay-locked
loop, which is roughly 3 MHz at OC-48.
The gain of the loop integrator is small for high jitter
frequencies, so that larger phase differences are needed to make
the loop control voltage big enough to tune the range of the
phase shifter. Large phase errors at high jitter frequencies
Rev. PrA | Page 19 of 33
ADN2865
Preliminary Technical Data
FUNCTIONAL DESCRIPTION
SERDES
The ADN2865 has an integrated serializer / deserializer and
clock divider which allows the continuous rate CDR to interface
directly to an FPGA or digital ASIC, such a s a Media Access
Controller (MAC), resulting in power and space savings.
TXCLK
TXDATA[7:0]
EDGE
DETECTOR
REGISTER
ALIGN
MODE
TXCLK
The recovered clock is divided by 16 and is used to transfer 8
bits of receive data to the MAC on both the rising and falling
edge. Both RXCLKP/N and RXDATAP/N[7:0] use LVDS
signaling for noise reasons and have a relative phase which is
adjustable via the I2C interface, per table 12 on page 14.
RECOVERED
CLOCK
Dn+1[7:0]
RESET
DIVIDE
REGISTER
DIV BY 8
BY 8
Dn[7:0]
COUNTER
SERIALISER
Figure 21. Align Mode Operation
Half rate (1.25Gb/s) transmit data can also be serialised by the
ADN2865 at the CML output using the recovered clock from
the receive channel. An optional CML clock output is available.
The parallel interface consists of 8 LVCMOS / LVTTL inputs
with an optional TXCLK at the divde by 8 rate. Two timing
modes are available, sync mode and align mode.
Sync Mode
This is the default mode of operation. and does not require a
TXCLK signal. Instead, TXDATA[7:0] is timed from RXCLK
and the round trip delay between these signals must meet the
setup and hold time requirement specified in table 3 to avoid
corrupting the serial bit stream. Sync mode is useful in
applications which require a stable timing relationship between
the input and output serial bit streams.
Align Mode
This mode is controlled using the I2C interface and requires the
use of TXCLK which is used to latch TXDATA internally.
When enabled, align mode centers this latched data with
respect to the internal divide by 8 sampling clock, which can
render the interface less sensitive to variation in the timing of
TXDATA[7:0] relative to RXCLK. In a typical application, the
propagation delay between RXCLK and TXDATA[7:0] will vary
with process, temperature and supply voltage through the
external MAC device. This variation can be calibrated out by
enabling and then disabling align mode. The downside to using
align mode is that the calibration process leads to additional
uncertainty in the serial bit timing relative to the input bit
stream by +/- 1 UI. In align mode, it is necessary to meet the
setup and hold time for TXDATA[7:0] relative to TXCLK.
Bit order reversal is supported for both the receive and transmit
parallel buses using the I2C interface.
FREQUENCY ACQUISITION
The ADN2865 acquires frequency from the data over a range of
data frequencies from 12.3 Mb/s to 2.7 Gb/s. The lock detector
circuit compares the frequency of the VCO and the frequency
of the incoming data. When these frequencies differ by more
than 1000 ppm, LOL is asserted. This initiates a frequency
acquisition cycle. The VCO frequency is reset to the bottom of
its range, which is 12.3 MHz. The frequency detector then
compares this VCO frequency and the incoming data frequency
and increments the VCO frequency, if necessary. Initially, the
VCO frequency is incremented in large steps to aid fast acquisition. As the VCO frequency approaches the data frequency, the
step size is reduced until the VCO frequency is within 250 ppm
of the data frequency, at which point LOL is de-asserted.
Once LOL is de-asserted, the frequency-locked loop is turned
off. The PLL/DLL pulls in the VCO frequency the rest of the
way until the VCO frequency equals the data frequency.
The frequency loop requires a single external capacitor between
CF1 and CF2, Pins 14 and 15. A 0.47 μF ± 20%, X7R ceramic
chip capacitor with < 10 nA leakage current is recommended.
Leakage current of the capacitor can be calculated by dividing
the maximum voltage across the 0.47 μF capacitor, ~3 V, by the
insulation resistance of the capacitor. The insulation resistance
of the 0.47 uF capacitor should be greater than 300 MΩ
LOCK DETECTOR OPERATION
The lock detector on the ADN2865 has three modes of
operation: normal mode, REFCLK mode, and static LOL mode.
Normal Mode
In normal mode, the ADN2865 is a continuous rate CDR that
locks onto any data rate from 12.3 Mb/s to 2.7 Gb/s without the
use of a reference clock as an acquisition aid. In this mode, the
lock detector monitors the frequency difference between the
VCO and the input data frequency, and de-asserts the loss of
lock signal, which appears on LOL Pin 30, when the VCO is
Rev. PrA | Page 20 of 33
Preliminary Technical Data
ADN2865
within 250 ppm of the data frequency. This enables the D/PLL,
which pulls the VCO frequency in the remaining amount and
also acquires phase lock. Once locked, if the input frequency
error exceeds 1000 ppm (0.1%), the loss of lock signal is reasserted and control returns to the frequency loop, which
begins a new frequency acquisition starting at the lowest point
in the VCO operating range, 12.3 MHz. The LOL pin remains
asserted until the VCO locks onto a valid input data stream to
within 250 ppm frequency error. This hysteresis is shown in
Figure 22.
LOL
–1000
–250
0
250
1000
fVCO ERROR
(ppm)
04228-0-018
1
Figure 22. Transfer Function of LOL
LOL Detector Operation Using a Reference Clock
In this mode, a reference clock is used as an acquisition aid to
lock the ADN2865 VCO. Lock to reference mode is enabled by
setting CTRLA[0] to 1. The user also needs to write to the
CTRLA[7:6] and CTRLA[5:2] bits in order to set the reference
frequency range and the divide ratio of the data rate with
respect to the reference frequency. For more details, see the
Reference Clock (Optional) section. In this mode, the lock
detector monitors the difference in frequency between the
divided down VCO and the divided down reference clock. The
loss of lock signal, which appears on the LOL Pin 30, is deasserted when the VCO is within 250 ppm of the desired
frequency. This enables the D/PLL, which pulls the VCO
frequency in the remaining amount with respect to the input
data and also acquires phase lock. Once locked, if the input
frequency error exceeds 1000 ppm (0.1%), the loss of lock signal
is re-asserted and control returns to the frequency loop, which
re-acquires with respect to the reference clock. The LOL pin
remains asserted until the VCO frequency is within 250 ppm of
the desired frequency. This hysteresis is shown in Figure 22.
Static LOL Mode
The ADN2865 implements a static LOL feature, which indicates
if a loss of lock condition has ever occurred and remains
asserted, even if the ADN2865 regains lock, until the static LOL
bit is manually reset. The I2C register bit, MISC[4], is the static
LOL bit. If there is ever an occurrence of a loss of lock
condition, this bit is internally asserted to logic high. The
MISC[4] bit remains high even after the ADN2865 has reacquired lock to a new data rate. This bit can be reset by writing
a 1 followed by 0 to I2C Register Bit CTRLB[6]. Once reset, the
MISC[4] bit remains de-asserted until another loss of lock
condition occurs.
Writing a 1 to I2C Register Bit CTRLB[7] causes the LOL pin,
Pin 16, to become a static LOL indicator. In this mode, the LOL
pin mirrors the contents of the MISC[4] bit and has the
functionality described in the previous paragraph. The
CTRLB[7] bit defaults to 0. In this mode, the LOL pin operates
in the normal operating mode, that is, it is asserted only when
the ADN2865 is in acquisition mode and de-asserts when the
ADN2865 has re-acquired lock.
HARMONIC DETECTOR
The ADN2865 provides a harmonic detector, which detects
whether or not the input data has changed to a lower harmonic
of the data rate that the VCO is currently locked onto. For
example, if the input data instantaneously changes from OC-48,
2.488 Gb/s, to an OC-12, 622.080 Mb/s bit stream, this could be
perceived as a valid OC-48 bit stream, because the OC-12 data
pattern is exactly 4× slower than the OC-48 pattern. So, if the
change in data rate is instantaneous, a 101 pattern at OC-12
would be perceived by the ADN2865 as a 111100001111 pattern
at OC-48. If the change to a lower harmonic is instantaneous, a
typical CDR could remain locked at the higher data rate.
The ADN2865 implements a harmonic detector that automatically identifies whether or not the input data has switched to a
lower harmonic of the data rate that the VCO is currently
locked onto. When a harmonic is identified, the LOL pin is
asserted and a new frequency acquisition is initiated. The
ADN2865 automatically locks onto the new data rate, and the
LOL pin is de-asserted.
However, the harmonic detector does not detect higher
harmonics of the data rate. If the input data rate switches to a
higher harmonic of the data rate the VCO is currently locked
onto, the VCO loses lock, the LOL pin is asserted, and a new
frequency acquisition is initiated. The ADN2865 automatically
locks onto the new data rate.
The time to detect lock to harmonic is
16,384 × (Td/ρ)
where:
1/Td is the new data rate. For example, if the data rate is
switched from OC-48 to OC-12, then Td = 1/622 MHz.
ρ is the data transition density. Most coding schemes seek to
ensure that ρ = 0.5, for example, PRBS, 8B/10B.
When the ADN2865 is placed in lock to reference mode, the
harmonic detector is disabled.
LIMITING AMPLIFIER
The limiting amplifier on the ADN2865 has differential inputs
(PIN/NIN), which are internally terminated with 50 Ω to an
on-chip voltage reference (VREF = 2.5 V typically). The inputs
are typically ac-coupled externally, although dc coupling is
possible as long as the input common mode voltage remains
above 2.5 V (see Figure , Figure , and Figure in the Applications
Rev. PrA | Page 21 of 33
ADN2865
Preliminary Technical Data
The quantizer slicing level can be offset by ±100 mV to mitigate
the effect of amplified spontaneous emission (ASE) noise or
duty cycle distortion by applying a differential voltage input of
up to ±0.95 V to SLICEP/N inputs. If no adjustment of the slice
level is needed, SLICEP/N should be tied to VEE. The gain of
the slice adjustment is ~0.1 V/V.
If the user is not using the BER monitoring function, sample
phase adjustment can be utilized to optimize the horizontal
sampling point of the incoming data eye. The ADN2865
automatically centers the sampling point to the best of its ability.
However, sample phase adjustment could be used to
compensate for any static phase offset of the CDR and duty
cycle distortion of the incoming eye. Sample phase adjustment
is applied to the incoming eye via the PHASE register. It is
important to note that sample phase adjustment can not be used
if the user is utilising the BER monitoring capability. This is
because the BER monitoring circuit requires control of the
sample phase adjustment circuitry. Also, using the sample phase
adjustment capability uses an additional 180mW of power.
LOSS OF SIGNAL (LOS) DETECTOR
The receiver front end LOS detector circuit detects when the
input signal level has fallen below a user-adjustable threshold.
The threshold is set with a single external resistor from Pin 9,
THRADJ, to VEE. The LOS comparator trip point-versusresistor value is illustrated in Figure 2. If the input level to the
ADN2865 drops below the programmed LOS threshold, the
output of the LOS detector, LOS Pin 1, is asserted to a Logic 1.
The LOS detector’s response time is ~500 ns by design, but is
dominated by the RC time constant in ac-coupled applications.
The LOS pin defaults to active high. However, by setting Bit
CTRLC[2] to 1, the LOS pin is configured as active low.
There is typically 6 dB of electrical hysteresis designed into the
LOS detector to prevent chatter on the LOS pin. This means
that, if the input level drops below the programmed LOS
threshold causing the LOS pin to assert, the LOS pin is not deasserted until the input level has increased to 6 dB (2×) above
the LOS threshold (see Figure ).
INPUT LEVEL
HYSTERESIS
LOS THRESHOLD
04228-0-017
SLICE AND SAMPLE PHASE ADJUST (ADN2817
ONLY)
LOS OUTPUT
INPUT VOLTAGE (VDIFF)
Information section). Input offset is factory trimmed to achieve
better than 6 mV typical sensitivity with minimal drift. The
limiting amplifier can be driven differentially or single-ended.
t
Figure 23. ADN2817 LOS Detector Hysteresis
The LOS detector and the SLICE level adjust can be used
simultaneously on the ADN2865. This means that any offset
added to the input signal by the SLICE adjust pins does not
affect the LOS detector’s measurement of the absolute input
level.
I2C INTERFACE
The ADN2865 supports a 2-wire, I2C compatible, serial bus
driving multiple peripherals. Two inputs, serial data (SDA) and
serial clock (SCK), carry information between any devices
connected to the bus. Each slave device is recognized by a
unique address. The 7-bit slave address is factory programmed
to binary ‘1100000’. The LSB of the word sets either a read or
write operation (see Figure ). Logic 1 corresponds to a read
operation, while Logic 0 corresponds to a write operation.
To control the device on the bus, the following protocol must be
followed. First, the master initiates a data transfer by establishing a start condition, defined by a high to low transition on
SDA while SCK remains high. This indicates that an
address/data stream follows. All peripherals respond to the start
condition and shift the next eight bits (the 7-bit address and the
R/W bit). The bits are transferred from MSB to LSB. The
peripheral that recognizes the transmitted address responds by
pulling the data line low during the ninth clock pulse. This is
known as an acknowledge bit. All other devices withdraw from
the bus at this point and maintain an idle condition. The idle
condition is where the device monitors the SDA and SCK lines
waiting for the start condition and correct transmitted address.
The R/W bit determines the direction of the data. Logic 0 on
the LSB of the first byte means that the master writes
information to the peripheral. Logic 1 on the LSB of the first
byte means that the master reads information from the
peripheral.
The ADN2865 acts as a standard slave device on the bus. The
data on the SDA pin is 8 bits long supporting the 7-bit addresses
plus the R/W bit. The ADN2865 has 8 subaddresses to enable
the user-accessible internal registers (see Table 6 through Table
15). It, therefore, interprets the first byte as the device address
and the second byte as the starting subaddress. Autoincrement
mode is supported, allowing data to be read from or written to
Rev. PrA | Page 22 of 33
Preliminary Technical Data
ADN2865
VCC
the starting subaddress and each subsequent address without
manually addressing the subsequent subaddress. A data transfer
is always terminated by a stop condition. The user can also
access any unique subaddress register on a one-by-one basis
without updating all registers.
CLK
OSC
A reference clock is not required to perform clock and data
recovery with the ADN2865. However, support for an optional
reference clock is provided. The reference clock can be driven
differentially or single-ended. If the reference clock is not being
used, then REFCLKP should be tied to VCC, and REFCLKN
can be left floating or tied to VEE (the inputs are internally
terminated to VCC/2). See Figure through Figure for sample
configurations.
The REFCLK input buffer accepts any differential signal with a
peak-to-peak differential amplitude of greater than 100 mV (for
example, LVPECL or LVDS) or a standard single-ended low
voltage TTL input, providing maximum system flexibility.
Phase noise and duty cycle of the reference clock are not critical
and 100 ppm accuracy is sufficient.
ADN2817/18
REFCLKP
OUT
10
Buffer
REFCLKN
x
11
Stop and start conditions can be detected at any stage of the
data transfer. If these conditions are asserted out of sequence
with normal read and write operations, then they cause an
immediate jump to the idle condition. During a given SCK high
period, the user should issue one start condition, one stop
condition, or a single stop condition followed by a single start
condition. If an invalid subaddress is issued by the user, the
ADN2865 does not issue an acknowledge and returns to the idle
condition. If the user exceeds the highest subaddress while
reading back in autoincrement mode, then the highest subaddress register contents continue to be output until the master
device issues a no-acknowledge. This indicates the end of a
read. In a no-acknowledge condition, the SDATA line is not
pulled low on the ninth pulse. See Figure and Figure for
sample read and write data transfers and Figure 12 for a more
detailed timing diagram.
REFERENCE CLOCK (OPTIONAL)
ADN2817/18
REFCLKP
100k
100k
VCC/2
Figure 25. Single-Ended REFCLK Configuration
VCC
ADN2817/18
10
REFCLKP
Buffer
NC 11
REFCLKN
100k
100k
VCC/2
Figure 26. No REFCLK Configuration
The two uses of the reference clock are mutually exclusive. The
reference clock can be used either as an acquisition aid for the
ADN2865 to lock onto data, or to measure the frequency of the
incoming data to within 0.01%. (There is the capability to
measure the data rate to approximately ±10% without the use of
a reference clock.) The modes are mutually exclusive, because,
in the first use, the user knows exactly what the data rate is and
wants to force the part to lock onto only that data rate; in the
second use, the user does not know what the data rate is and
wants to measure it.
Lock to reference mode is enabled by writing a 1 to I2C Register
Bit CTRLA[0]. Fine data rate readback mode is enabled by
writing a 1 to I2C Register Bit CTRLA[1]. Writing a 1 to both of
these bits at the same time causes an indeterminate state and is
not supported.
Using the Reference Clock to Lock onto Data
In this mode, the ADN2865 locks onto a frequency derived
from the reference clock according to the following equation:
10
Buffer
11
Data Rate/2CTRLA[5:2] = REFCLK/2CTRLA[7:6]
REFCLKN
100k
100k
VCC/2
Figure 24. Differential REFCLK Configuration
The user must know exactly what the data rate is, and provide a
reference clock that is a function of this rate. The ADN2865 can
still be used as a continuous rate device in this configuration,
provided that the user has the ability to provide a reference
clock that has a variable frequency (see Application Note
AN-632).
The reference clock can be anywhere between 12.3 MHz and
200 MHz. By default, the ADN2865 expects a reference clock of
between 12.3 MHz and 25 MHz. If it is between 25 MHz and
Rev. PrA | Page 23 of 33
ADN2865
Preliminary Technical Data
50 MHz, 50 MHz and 100 MHz, or 100 MHz and 200 MHz, the
user needs to configure the ADN2865 to use the correct
reference frequency range by setting two bits of the CTRLA
register, CTRLA[7:6].
Prior to reading back the data rate using the reference clock, the
CTRLA[7:6] bits must be set to the appropriate frequency range
with respect to the reference clock being used. A fine data rate
readback is then executed as follows:
Table 16. CTRLA Settings
Step 1: Write a 1 to CTRLA[1]. This enables the fine data rate
measurement capability of the ADN2865. This bit is level
sensitive and does not need to be reset to perform subsequent
frequency measurements.
CTRLA[7:6]
00
01
10
11
Range (MHz)
12.3 to 25
25 to 50
50 to 100
100 to 200
CTRLA[5:2]
0000
0001
n
1000
Ratio
1
2
2n
256
The user can specify a fixed integer multiple of the reference
clock to lock onto using CTRLA[5:2], where CTRLA should be
set to the data rate/DIV_FREF, where DIV_FREF represents the
divided-down reference referred to the 12.3 MHz to 25 MHz
band. For example, if the reference clock frequency was
38.88 MHz and the input data rate was 622.08 Mb/s, then
CTRLA[7:6] would be set to [01] to give a divided-down
reference clock of 19.44 MHz. CTRLA[5:2] would be set to
[0101], that is, 5, because
Step 2: Reset MISC[2] by writing a 1 followed by a 0 to
CTRLB[3]. This initiates a new data rate measurement.
Step 3: Read back MISC[2]. If it is 0, then the measurement is
not complete. If it is 1, then the measurement is complete and
the data rate can be read back on FREQ[22:0]. The time for a
data rate measurement is typically 80 ms.
Step 4: Read back the data rate from registers FREQ2[6:0],
FREQ1[7:0], and FREQ0[7:0].
Use the following equation to determine the data rate:
5
f DATARATE = (FREQ [22..0]× f REFCLK )/ 2 (14 + SEL _ RATE )
622.08 Mb/s/19.44 MHz = 2
In this mode, if the ADN2865 loses lock for any reason, it
relocks onto the reference clock and continues to output a stable
clock.
While the ADN2865 is operating in lock to reference mode, if
the user ever changes the reference frequency, the FREF range
(CTRLA[7:6]), or the FREF ratio (CTRLA[5:2]), this must be
followed by writing a 0 to 1 transition into the CTRLA[0] bit to
initiate a new lock to reference command.
where:
FREQ[22:0] is the reading from FREQ2[6:0] (MSByte),
FREQ1[7:0], and FREQ0[7:0] (LSByte).
Table 17.
D22
D21...D17
FREQ2[6:0]
D16
D15
D14...D9
D8
FREQ1[7:0]
D7
D6...D1
D0
FREQ0[7:0]
fDATARATE is the data rate (Mb/s).
Using the Reference Clock to Measure Data Frequency
The user can also provide a reference clock to measure the
recovered data frequency. In this case, the user provides a
reference clock, and the ADN2865 compares the frequency of
the incoming data to the incoming reference clock and returns a
ratio of the two frequencies to 0.01% (100 ppm). The accuracy
error of the reference clock is added to the accuracy of the
ADN2865 data rate measurement. For example, if a 100-ppm
accuracy reference clock is used, the total accuracy of the
measurement is within 200 ppm.
The reference clock can range from 12.3 MHz and 200 MHz.
The ADN2865 expects a reference clock between 12.3 MHz and
25 MHz by default. If it is between 25 MHz and 50 MHz,
50 MHz and 100 MHz, or 100 MHz and 200 MHz, the user
needs to configure the ADN2865 to use the correct reference
frequency range by setting two bits of the CTRLA register,
CTRLA[7:6]. Using the reference clock to determine the
frequency of the incoming data does not affect the manner in
which the part locks onto data. In this mode, the reference clock
is used only to determine the frequency of the data. For this
reason, the user does not need to know the data rate to use the
reference clock in this manner.
fREFCLK is the REFCLK frequency (MHz).
SEL_RATE is the setting from CTRLA[7:6].
For example, if the reference clock frequency is 32 MHz,
SEL_RATE = 1, since the CTRLA[7:6] setting would be [01],
because the reference frequency would fall into the 25 MHz to
50 MHz range. Assume for this example that the input data rate
is 2.488 Gb/s (OC-48). After following Steps 1 through 4, the
value that is read back on FREQ[22:0] = 0x26E010, which is
equal to 2.5477 × 106. Plugging this value into the equation
yields
(2.5477e6 × 32e6)/(2 (14 +1) ) = 2.488 Gb/s
If subsequent frequency measurements are required, CTRLA[1]
should remain set to 1. It does not need to be reset. The
measurement process is reset by writing a 1 followed by a 0 to
CTRLB[3]. This initiates a new data rate measurement. Follow
Steps 2 through 4 to read back the new data rate.
Note: A data rate readback is valid only if LOL is low. If LOL is
high, the data rate readback is invalid.
Rev. PrA | Page 24 of 33
Preliminary Technical Data
ADN2865
2.
Additional Features Available via the I2C Interface
Coarse Data Rate Readback
The data rate can be read back over the I2C interface to
approximately +10% without the need of an external reference
clock. A 9-bit register, COARSE_RD[8:0], can be read back
when LOL is de-asserted. The 8 MSBs of this register are the
contents of the RATE[7:0] register. The LSB of the
COARSE_RD register is Bit MISC[0].
Table provides coarse data rate readback to within ±10%.
The subharmonic must be continued to be applied
until LOL goes LOW, i.e. until acquisition is
completed. It doesn't matter how long the
subharmonic remains after LOL goes LOW.
In FDDI Mode, the output of the ADN2865 is squelched until
the device has acquired lock of the subharmonic input. This
causes all zeros to be transmitted out of the 2865 until lock has
been achieved. Once locked, the outputs are enabled and begin
transmitting data. For FDDI protocol, this would be when the
'H' symbols are being transmitted during link synchronization.
Fi
LOS Configuration
CLK HOLDOVER MODE
The LOS detector output, LOS Pin 22, can be configured to be
either active high or active low. If CTRLC[2] is set to Logic 0
(default), the LOS pin is active high when a loss of signal
condition is detected. Writing a 1 to CTRLC[2] configures the
LOS pin to be active low when a loss of signal condition is
detected.
System Reset
A frequency acquisition can be initiated by writing a 1 followed
by a 0 to the I2C Register Bit CTRLB[5]. This initiates a new
frequency acquisition while keeping the ADN2865 in the
operating mode that it was previously programmed to in
registers CTRL[A], CTRL[B], and CTRL[C].
FDDI Mode
A scheme has been implemented on the ADN2865 that enables
the device to lock to input data streams that appear as subharmonics of the desired datarate, e.g. FDDI during link
synchronization. This works for any code where a subharmonic
down to the 31st is transmitted. FDDI uses the 5th
subharmonic. The implementation requires certain
programming by the user and more importantly certain
assumptions about the incoming data.
The user is required to program the part into FDDI mode by
setting bit FDDI_MODE[7]=1. The user then needs to program
the target datarate, (for FDDI this is 125MHz). This is done by
programming an upper and lower 9-bit code into I2C registers
HI_CODE[8..0], LO_CODE[8..0], and CODE_LSB[1..0]. See
Table XX for a look-up table showing the correct register
settings for each datarate. The user must also program the
subharmonic ratio into I2C register FDDI_MODE[6..2] that the
ADN2865 needs to lock on to, e.g. FDDI_MODE[6..2] = 00101
for FDDI (5th subharmonic). The user has to de-program FDDI
mode before the next datarate is applied.
Here is what is required of the incoming data:
1.
The subharmonic must be a clock-type waveform i.e.
transition density equal to 1 at the subharmonic
frequency.
CLK Holdover Mode 2A:
This mode of operation will be available in all LTD modes: The
output clock frequency will remain within +/-5% if the input
data is removed or changed. To operate in this mode, the user
would write to the I2C to put the part into CLK Holdover Mode
2A mode by setting SEL_MODE[2]=1. The user must then
initiate an acquisition via a software reset. The device will then
lock onto the input datarate. At this point the output frequency
remains within +/- 5% of the intial acquired value regardless of
whether or not the input data is taken away or the datarate
changes. Only a sw reset can initiate a new acquistion in this
mode.
CLK Holdover Mode 2B:
This mode is selected by setting SEL_MODE[1]=1. In this
mode, the output clock stays within +/-5% of the initial
acquired frequency, even if the input data is taken away. Unlike
CLK Holdover Mode 2A, in this mode the ADN2865 will
initiate a new frequency acquisition automatically if the input
datarate changes. This mode requires the inputs to be DC
coupled because if the inputs are AC coupled and the input is
taken away, any noise present on the inputs may be large
enough to trigger a new frequency acquisition which would
cause the clock output frequency to change.
CDR BYPASS MODE
The CDR on the ADN2865 can be bypassed by setting bit
CTRLD[7]=1. In this mode the ADN2865 will feed the input
directly through the input amplifiers to the output buffer,
completely bypassing the CDR.
DISABLE OUTPUT BUFFERS
The ADN2865 provides the option of disabling the output
buffers for power savings. The LVDS output buffers can be
disabled by setting CTRLD[6]=1. For additional power savings,
e.g. in a low power standby mode, the CML output buffers can
also be disabled by setting CTRLD[5]=1.
Rev. PrA | Page 25 of 33
ADN2865
Preliminary Technical Data
APPLICATIONS INFORMATION
PCB DESIGN GUIDELINES
Proper RF PCB design techniques must be used for optimal
performance.
Power Supply Connections and Ground Planes
Use of one low impedance ground plane is recommended. The
VEE pins should be soldered directly to the ground plane to
reduce series inductance. If the ground plane is an internal
plane and connections to the ground plane are made through
vias, multiple vias can be used in parallel to reduce the series
inductance. The exposed pad should be connected to the GND
plane using plugged vias so that solder does not leak through
the vias during reflow.
By using adjacent power supply and GND planes, excellent high
frequency decoupling can be realized by using close spacing
between the planes. This capacitance is given by
Cplane = 0.88ε r A/d (pF )
where:
εr is the dielectric constant of the PCB material.
A is the area of the overlap of power and GND planes (cm2).
d is the separation between planes (mm).
For FR-4, εr = 4.4 mm and 0.25 mm spacing, C ~15 pF/
15
16
17
18
19
20
21
22
23
24
25
26
27
28
NC
TXDAT4
TXCLK
TXDAT3
TXDAT2
TXDAT1
TXDAT0
VREG
CF1
VEE
VCC
VEE
VCC
REFN
REFP
........
56
55
54
53
52
51
50
49
48
47
46
45
44
43
RXDATP2
RXDATN2
RXDATP3
RXDATN3
RXDATP4
RXDATN4
VCC
RXDATP5
RXDATN5
RXDATP6
RXDATN6
VCC
RXDATP7
RXDATN7
..
Use of a 10 μF electrolytic capacitor between VCC and VEE is
recommended at the location where the 3.3 V supply enters the
PCB. When using 0.1 μF and 1 nF ceramic chip capacitors, they
should be placed between the IC power supply VCC and VEE,
as close as possible to the ADN2865 VCC pins.
If connections to the supply and ground are made through vias,
the use of multiple vias in parallel helps to reduce series
inductance, especially on Pins 7,45 & 50, which supplies power
to the high speed LVDS & CML output buffers. Refer to the
schematic in Figure for recommended connections.
Figure 27. Typical ADN2865 Applications Circuit
Rev. PrA | Page 26 of 33
Preliminary Technical Data
ADN2865
Transmission Lines
Use of 50 Ω transmission lines is required for all LVDS and
CML input and output signals to minimize reflections: PIN,
NIN, RXDATAP/N[7:0], RXCLKP/N, SERDATP, SERDATN,
SERCLKP, SERCLKN (also REFCLKP, REFCLKN, if a high
frequency reference clock is used, such as 155 MHz). It is also
necessary for the PIN/NIN input traces to be matched in length,
and the parallel bus / CML output traces to be matched in
length to avoid skew between the differential traces. All high
speed CML outputs, SERDATP,SERDATN,SERCLKP,SERCLKN
also require 100 Ω back termination chip resistors connected
between the output pin and VCC. These resistors should be
placed as close as possible to the output pins. These 100 Ω
resistors are in parallel with on-chip 100 Ω termination resistors
to create a 50 Ω back termination (see Figure ).
The high speed inputs, PIN and NIN, are internally terminated
with 50 Ω to an internal reference voltage (see Figure ). A 0.1 μF
is recommended between VREF, Pin 36, and GND to provide
an ac ground for the inputs.
As with any high speed mixed-signal design, take care to keep
all high speed digital traces away from sensitive analog nodes.
VCC
VCC
100
100
100
Choosing AC Coupling Capacitors
AC coupling capacitors at the input (PIN, NIN) and output
(SERDATP,SERDATN) of the ADN2865 must be chosen such
that the device works properly over the full range of data rates
used in the application. When choosing the capacitors, the time
constant formed with the two 50 Ω resistors in the signal path
must be considered. When a large number of consecutive
identical digits (CIDs) are applied, the capacitor voltage can
droop due to baseline wander (see Figure ), causing patterndependent jitter (PDJ).
The user must determine how much droop is tolerable and
choose an ac coupling capacitor based on that amount of droop.
The amount of PDJ can then be approximated based on the
capacitor selection. The actual capacitor value selection may
require some trade-offs between droop and PDJ.
Example: Assuming that 2% droop can be tolerated, then the
maximum differential droop is 4%. Normalizing to Vpp:
Droop = Δ V = 0.04 V = 0.5 Vpp (1 − e–t/τ) ; therefore, τ = 12t
VTERM
100
package has a central exposed pad. The pad on the printed
circuit board should be at least as large as this exposed pad. The
user must connect the exposed pad to VEE using plugged vias
so that solder does not leak through the vias during reflow. This
ensures a solid connection from the exposed pad to VEE.
0.1μ
where:
50
τ is the RC time constant (C is the ac coupling capacitor, R =
100 Ω seen by C).
0. 1μ 50Ω
t is the total discharge time, which is equal to nΤ.
50
n is the number of CIDs.
VTERM
ADN2865
T is the bit period.
The capacitor value can then be calculated by combining the
equations for τ and t:
Figure 28. Typical ADN2865 Applications Circuit
VC C
C = 12nT/R
A D N 2 86 5
TIA
50 Ω
CIN
PIN
C IN
N IN
Once the capacitor value is selected, the PDJ can be
approximated as
50
0. 1u F
(
VREF
)
PDJ pspp = 0.5t r 1 − e ( −nT/RC ) / 0.6
50
2.5V
3k
where:
PDJpspp is the amount of pattern-dependent jitter allowed;
< 0.01 UI p-p typical.
Figure 29. ADN2865 AC-Coupled Input Configuration
Soldering Guidelines for Chip Scale Package
The lands on the 56 LFCSP are rectangular. The printed circuit
board pad for these should be 0.1 mm longer than the package
land length and 0.05 mm wider than the package land width.
The land should be centered on the pad. This ensures that the
solder joint size is maximized. The bottom of the chip scale
tr is the rise time, which is equal to 0.22/BW,
where BW ~ 0.7 (bit rate).
Note that this expression for tr is accurate only for the inputs.
The output rise time for the ADN2865 is ~100 ps regardless of
data rate.
Rev. PrA | Page 27 of 33
ADN2865
Preliminary Technical Data
VCC
V1
V2
DATAOU T P
50
CI N
T IA
AD N 2817
PIN
VREF
C OUT
CD R
L imamp
50
V1b
1
V2b
DATAOU T N
N IN
2
4
3
V1
V1b
V2
V2b
Vref
Vdiff
VT H
Vdiff = V2-V2b
VT H = AD N 2817 Quantizer T hreshold
N OT ES:
1. D uring data patterns with high transition density, differential D C voltage at V1 and V2 is zero.
2. When the output of the T I A goes to CI D, V1 and V1b are driven to different D C levels. V2 and V2b discharge to the Vref level which
effectively introduces a differential D C offset across the AC coupling capacitors.
3. When the burst of data starts again, the differential D C offset across the AC coupling capacitors is applied to the input levels causing
a D C shift in the differential input. T his shift is large enough such that one of the states, either H I or L O depending on the levels of
V1 and V1b when the T IA went to CID, is cancelled out. T he quantizer will not recognize this as a valid state.
4. T he D C offset slowly discharges until the differential input voltage exceeds the sensitivity of the AD N 2817. T he quantizer will be able
to recognize both H I and L O states at this point.
Figure 30. Example of Baseline Wander
DC-COUPLED APPLICATION
VCC
The inputs to the ADN2865 can also be dc-coupled. This might
be necessary in burst mode applications, where there are long
periods of CIDs, and baseline wander cannot be tolerated. If the
inputs to the ADN2865 are dc-coupled, care must be taken not
to violate the input range and common-mode level requirements of the ADN2865 (see Figure through Figure ). If dc
coupling is required, and the output levels of the TIA do not
adhere to the levels shown in Figure , then level shifting and/or
an attenuator must be between the TIA outputs and the
ADN2865 inputs.
ADN2865
PI N
TIA
50Ω
NIN
50
0.1uF
VREF
Figure 31. DC-Coupled Application
Rev. PrA | Page 28 of 33
50
2.5V
3k
Preliminary Technical Data
ADN2865
VPP = PIN – NIN = 2 × VSE = 2.0V MAX
PIN
INPUT (V)
VPP = PIN – NIN = 2 × VSE = 10mV AT SENSITIVITY
VSE = 5mV MIN
VCM = 2.3V MIN
(DC-COUPLED)
NIN
Figure 32. Minimum Allowed DC-Coupled Input Levels
04228-0-028
NIN
VCM = 2.3V
(DC-COUPLED)
04228-0-027
INPUT (V)
VSE = 1.0V MAX
PIN
Figure 33. Maximum Allowed DC-Coupled Input Levels
Rev. PrA | Page 29 of 33
ADN2865
Preliminary Technical Data
COARSE DATA RATE READBACK LOOK-UP TABLE
Code is the 9-bit value read back from COARSE_RD[8:0].
Table 18. Look-Up Table
Code
0
1
2
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
41
42
43
44
45
46
47
FMID
5.1934e+06
5.1930e+06
5.2930e+06
5.3989e+06
5.5124e+06
5.6325e+06
5.7612e+06
5.8995e+06
6.0473e+06
6.2097e+06
6.3819e+06
6.5675e+06
6.7688e+06
6.9874e+06
7.2262e+06
7.4863e+06
7.4139e+06
7.4135e+06
7.5606e+06
7.7173e+06
7.8852e+06
8.0633e+06
8.2548e+06
8.4586e+06
8.6784e+06
8.9180e+06
9.1736e+06
9.4481e+06
9.7464e+06
1.0068e+07
1.0417e+07
1.0791e+07
1.0387e+07
1.0386e+07
1.0586e+07
1.0798e+07
1.1025e+07
1.1265e+07
1.1522e+07
1.1799e+07
1.2095e+07
1.2419e+07
1.2764e+07
1.3135e+07
1.3538e+07
1.3975e+07
1.4452e+07
1.4973e+07
Code
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
FMID
1.4828e+07
1.4827e+07
1.5121e+07
1.5435e+07
1.5770e+07
1.6127e+07
1.6510e+07
1.6917e+07
1.7357e+07
1.7836e+07
1.8347e+07
1.8896e+07
1.9493e+07
2.0136e+07
2.0833e+07
2.1582e+07
2.0774e+07
2.0772e+07
2.1172e+07
2.1596e+07
2.2049e+07
2.2530e+07
2.3045e+07
2.3598e+07
2.4189e+07
2.4839e+07
2.5527e+07
2.6270e+07
2.7075e+07
2.7950e+07
2.8905e+07
2.9945e+07
2.9655e+07
2.9654e+07
3.0242e+07
3.0869e+07
3.1541e+07
3.2253e+07
3.3019e+07
3.3834e+07
3.4714e+07
3.5672e+07
3.6694e+07
3.7792e+07
3.8985e+07
4.0273e+07
4.1666e+07
4.3164e+07
Code
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
Rev. PrA | Page 30 of 33
FMID
4.1547e+07
4.1544e+07
4.2344e+07
4.3191e+07
4.4099e+07
4.5060e+07
4.6090e+07
4.7196e+07
4.8378e+07
4.9678e+07
5.1055e+07
5.2540e+07
5.4150e+07
5.5899e+07
5.7810e+07
5.9890e+07
5.9311e+07
5.9308e+07
6.0485e+07
6.1739e+07
6.3081e+07
6.4506e+07
6.6038e+07
6.7669e+07
6.9427e+07
7.1344e+07
7.3388e+07
7.5585e+07
7.7971e+07
8.0546e+07
8.3333e+07
8.6328e+07
8.3095e+07
8.3087e+07
8.4689e+07
8.6383e+07
8.8198e+07
9.0120e+07
9.2179e+07
9.4392e+07
9.6757e+07
9.9356e+07
1.0211e+08
1.0508e+08
1.0830e+08
1.1180e+08
1.1562e+08
1.1978e+08
Code
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
FMID
1.1862e+08
1.1862e+08
1.2097e+08
1.2348e+08
1.2616e+08
1.2901e+08
1.3208e+08
1.3534e+08
1.3885e+08
1.4269e+08
1.4678e+08
1.5117e+08
1.5594e+08
1.6109e+08
1.6667e+08
1.7266e+08
1.6619e+08
1.6617e+08
1.6938e+08
1.7277e+08
1.7640e+08
1.8024e+08
1.8436e+08
1.8878e+08
1.9351e+08
1.9871e+08
2.0422e+08
2.1016e+08
2.1660e+08
2.2360e+08
2.3124e+08
2.3956e+08
2.3724e+08
2.3723e+08
2.4194e+08
2.4695e+08
2.5233e+08
2.5802e+08
2.6415e+08
2.7067e+08
2.7771e+08
2.8538e+08
2.9355e+08
3.0234e+08
3.1188e+08
3.2218e+08
3.3333e+08
3.4531e+08
Preliminary Technical Data
Code
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
FMID
3.3238e+08
3.3235e+08
3.3876e+08
3.4553e+08
3.5279e+08
3.6048e+08
3.6872e+08
3.7757e+08
3.8703e+08
3.9742e+08
4.0844e+08
4.2032e+08
4.3320e+08
4.4719e+08
4.6248e+08
4.7912e+08
4.7449e+08
4.7447e+08
4.8388e+08
4.9391e+08
5.0465e+08
5.1605e+08
5.2831e+08
5.4135e+08
Code
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
ADN2865
FMID
5.5542e+08
5.7075e+08
5.8711e+08
6.0468e+08
6.2377e+08
6.4437e+08
6.6666e+08
6.9062e+08
6.6476e+08
6.6470e+08
6.7751e+08
6.9106e+08
7.0558e+08
7.2096e+08
7.3743e+08
7.5514e+08
7.7405e+08
7.9485e+08
8.1688e+08
8.4064e+08
8.6640e+08
8.9438e+08
9.2496e+08
9.5825e+08
Code
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
Rev. PrA | Page 31 of 33
FMID
9.4898e+08
9.4893e+08
9.6776e+08
9.8782e+08
1.0093e+09
1.0321e+09
1.0566e+09
1.0827e+09
1.1108e+09
1.1415e+09
1.1742e+09
1.2094e+09
1.2475e+09
1.2887e+09
1.3333e+09
1.3812e+09
1.3295e+09
1.3294e+09
1.3550e+09
1.3821e+09
1.4112e+09
1.4419e+09
1.4749e+09
1.5103e+09
Code
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
FMID
1.5481e+09
1.5897e+09
1.6338e+09
1.6813e+09
1.7328e+09
1.7888e+09
1.8499e+09
1.9165e+09
1.8980e+09
1.8979e+09
1.9355e+09
1.9756e+09
2.0186e+09
2.0642e+09
2.1132e+09
2.1654e+09
2.2217e+09
2.2830e+09
2.3484e+09
2.4187e+09
2.4951e+09
2.5775e+09
2.6666e+09
2.7625e+09
ADN2865
Preliminary Technical Data
OUTLINE DIMENSIONS
Figure 34. 56-Lead Frame Chip Scale Package [LFCSP]
(CP-56)
Dimensions shown in millimeters
ORDERING GUIDE
Model
ADN2865ACP
ADN2865ACP-RL
ADN2865ACP-RL7
Temperature Range
−40°C to 85°C
−40°C to 85°C
−40°C to 85°C
Package Description
56-LFCSP
56-LFCSP, tape-reel, 2500 pcs
56-LFCSP, tape-reel, 1500 pcs
Rev. PrA | Page 32 of 33
Package Option
CP-56
CP-56
CP-56
Preliminary Technical Data
ADN2865
PR06000-0-3/06(PrA)
NOTES
Rev. PrA | Page 33 of 33