ADN2812ACPZ-RL [ADI]
Continuous Rate 12.3 Mb/s to 2.7 Gb/s Clock and Data Recovery; 连续速率12.3 Mb / s至2.7 Gb / s的时钟和数据恢复
| 型号： | ADN2812ACPZ-RL |
| 厂家： | 
ADI |
| 描述： | Continuous Rate 12.3 Mb/s to 2.7 Gb/s Clock and Data Recovery |
| 文件： | 总28页 (文件大小：409K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Continuous Rate 12.3 Mb/s to 2.7 Gb/s Clock and
Data Recovery IC with Integrated Limiting Amp
Data Sheet
ADN2812
FEATURES
GENERAL DESCRIPTION
Serial data input: 12.3 Mb/s to 2.7 Gb/s
Exceeds SONET requirements for jitter transfer/
generation/tolerance
Quantizer sensitivity: 6 mV typical
Adjustable slice level: 100 mV
Patented clock recovery architecture
Loss of signal (LOS) detect range: 3 mV to 15 mV
Independent slice level adjust and LOS detector
No reference clock required
The ADN2812 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. The ADN2812 auto-
matically locks to all data rates without the need for an external
reference clock or programming. All SONET jitter requirements
are met, 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.
Loss of lock indicator
I2C interface to access optional features
Single-supply operation: 3.3 V
The receiver front end, loss of signal (LOS) detector circuit
indicates when the input signal level has fallen below a user-
adjustable threshold. The LOS detect circuit has hysteresis to
prevent chatter at the output.
Low power: 750 mW typical
5 mm × 5 mm 32-lead LFCSP
APPLICATIONS
SONET OC-1/OC-3/OC-12/OC-48 and all associated FEC rates
Fibre Channel, 2× Fibre Channel, GbE, HDTV
WDM transponders
The ADN2812 is available in a compact 5 mm × 5 mm 32-lead
lead frame chip scale package (LFCSP).
Regenerators/repeaters
Test equipment
Broadband cross-connects and routers
FUNCTIONAL BLOCK DIAGRAM
REFCLKP/N
(OPTIONAL)
LOL
CF1
CF2 VCC
VEE
2
LOOP
FILTER
FREQUENCY
DETECT
SLICEP/N
PIN
PHASE
SHIFTER
PHASE
DETECT
LOOP
FILTER
QUANTIZER
VCO
NIN
VREF
LOS
DETECT
DATA
RE-TIMING
2
2
THRADJ
LOS
DATAOUTP/N
CLKOUTP/N
Figure 1.
Rev. E
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibilityis assumed by Analog Devices for its use, nor for any infringements of patents or other
rightsof third parties that may result fromits 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 andregisteredtrademarks 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: 781.461.3113 ©2004–2012 Analog Devices, Inc. All rights reserved.
ADN2812
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Jitter Generation ......................................................................... 13
Jitter Transfer .............................................................................. 13
Jitter Tolerance............................................................................ 13
Theory of Operation ...................................................................... 14
Functional Description.................................................................. 16
Frequency Acquisition............................................................... 16
Limiting Amplifier ..................................................................... 16
Slice Adjust.................................................................................. 16
LOS Detector .............................................................................. 16
Lock Detector Operation .......................................................... 16
Harmonic Detector .................................................................... 17
Squelch Mode ............................................................................. 17
I2C Interface ................................................................................ 18
Reference Clock (Optional) ...................................................... 18
Applications Information .............................................................. 21
PCB Design Guidelines ............................................................. 21
DC-Coupled Application .......................................................... 23
Coarse Data Rate Readback Look-Up Table ............................... 24
Outline Dimensions....................................................................... 26
Ordering Guide .......................................................................... 26
Applications....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Jitter Specifications....................................................................... 4
Output and Timing Specifications............................................. 5
Absolute Maximum Ratings............................................................ 6
Thermal Characteristics .............................................................. 6
ESD Caution.................................................................................. 6
Timing Characteristics..................................................................... 7
Pin Configuration and Function Descriptions............................. 8
Typical Performance Characteristics ............................................. 9
I2C Interface Timing and Internal Register Description........... 10
Terminology .................................................................................... 12
Input Sensitivity and Input Overdrive..................................... 12
Single-Ended vs. Differential .................................................... 12
LOS Response Time ................................................................... 12
Jitter Specifications ......................................................................... 13
REVISION HISTORY
3/12—Rev. D to Rev. E
Changes to LTR Mode Description ............................................. 19
Changes to Ordering Guide.......................................................... 26
Updated Outline Dimensions....................................................... 26
Changes to Ordering Guide .......................................................... 26
11/04—Rev. 0 to Rev. A
5/10—Rev. C to Rev. D
Change to Specification....................................................................3
Updated Outline Dimensions....................................................... 26
Changes to Using the Reference Clock to Lock onto Data
Section.............................................................................................. 19
Changes to Figure 4, Table 5 ........................................................... 8
Changes to Figure 24...................................................................... 21
2/09—Rev. B to Rev. C
3/04—Revision 0: Initial Version
Updated Outline Dimensions....................................................... 26
Changes to Ordering Guide .......................................................... 26
6/07—Rev. A to Rev. B
Changes to Table 1 ............................................................................ 3
Changes to Table 6 .......................................................................... 11
Rev. E | Page 2 of 28
Data Sheet
ADN2812
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
Conditions
Min
Typ
Max
Unit
QUANTIZER—DC CHARACTERISTICS
Input Voltage Range
Peak-to-Peak Differential Input
Input Common-Mode Level
@ PIN or NIN, dc-coupled
PIN – NIN
DC-coupled (see Figure 28, Figure 29,
and Figure 30)
1.8
2.8
2.0
2.8
V
V
2.3
2.5
V
Differential Input Sensitivity
Input Overdrive
Input Offset
223 − 1 PRBS, ac-coupled,1 BER = 1 × 10–10
(see Figure 12)
10
5
6
3
500
290
mV p-p
mV p-p
µV
Input RMS Noise
BER = 1 x 10–10
µV rms
QUANTIZER—AC CHARACTERISTICS
Data Rate
S11
Input Resistance
Input Capacitance
12.3
2700
Mb/s
dB
Ω
@ 2.5 GHz
Differential
−15
100
0.65
pF
QUANTIZER—SLICE ADJUSTMENT
Gain
SLICEP – SLICEN = 0.5 V
SLICEP – SLICEN
DC level @ SLICEP or SLICEN
0.08
−0.95
VEE
0.1
1
0.125
+0.95
0.95
V/V
V
V
Differential Control Voltage Input
Control Voltage Range
Slice Threshold Offset
LOSS OF SIGNAL DETECT (LOS)
Loss of Signal Detect Range
mV
RThresh = 0 Ω (see Figure 5)
RThresh = 100 kΩ
OC-48
11
1.5
13
3
17
4.0
mV
mV
Hysteresis (Electrical)
RThresh = 0 Ω
RThresh = 100 kΩ
OC-1
5.6
3.7
6
6
7.2
8.4
dB
dB
RThresh = 0 Ω
5.6
2.0
6
4
500
450
7.2
6.7
dB
dB
ns
ns
RThresh = 10 kΩ
DC-coupled2
DC-coupled2
LOS Assert Time
LOS Deassert Time
LOSS OF LOCK DETECT (LOL)
VCO Frequency Error for LOL Assert
VCO Frequency Error for LOL Deassert
LOL Response Time
With respect to nominal
With respect to nominal
12.3 Mb/s
1000
250
4
ppm
ppm
ms
OC-12
OC-48
1.0
1.0
µs
µs
ACQUISITION TIME
Lock to Data Mode
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
Optional Lock to REFCLK Mode
Rev. E | Page 3 of 28
ADN2812
Data Sheet
Parameter
Conditions
Min
Typ
Max
Unit
DATA RATE READBACK ACCURACY
Coarse Readback
See Table 14
10
%
Fine Readback
In addition to REFCLK accuracy
Data rate ≤ 20 Mb/s
Data rate > 20 Mb/s
200
100
3.6
ppm
ppm
V
POWER SUPPLY VOLTAGE
3.0
3.3
POWER SUPPLY CURRENT
235
259
+85
mA
°C
OPERATING TEMPERATURE RANGE
–40
1 PIN and NIN should be differentially driven and ac-coupled for optimum sensitivity.
2 When ac-coupled, the LOS assert and deassert time is dominated by the RC time constant of the ac coupling capacitor and the 50 Ω input termination of the
ADN2812 input stage.
JITTER 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 2.
Parameter
Conditions
Min
Typ
Max
Unit
PHASE-LOCKED LOOP CHARACTERISTICS
Jitter Transfer BW
OC-48
OC-12
490
71
670
108
kHz
kHz
OC-3
23
35
kHz
Jitter Peaking
OC-48
OC-12
OC-3
0
0
0
0.03
0.03
0.03
0.002
0.037
0.002
0.019
0.002
0.011
dB
dB
dB
UI rms
UI p-p
UI rms
UI p-p
UI rms
UI p-p
Jitter Generation
OC-48, 12 kHz to 20 MHz
0.001
0.02
0.001
0.01
0.001
0.01
OC-12, 12 kHz to 5 MHz
OC-3, 12 kHz to 1.3 MHz
Jitter Tolerance
OC-48, 223 − 1 PRBS
600 Hz
70
19
3.8
0.75
0.4
92
45
5
1
0.6
UI p-p
UI p-p
UI p-p
UI p-p
UI p-p
6 kHz
100 kHz
1 MHz
20 MHz
OC-12, 223 − 1 PRBS
30 Hz1
100
44
2.5
1.0
UI p-p
UI p-p
UI p-p
UI p-p
300 Hz1
25 kHz
250 kHz1
OC-3, 223 − 1 PRBS
30 Hz1
50
24
3.5
1.0
UI p-p
UI p-p
UI p-p
UI p-p
300 Hz1
6500 Hz
65 kHz
1 Jitter tolerance of the ADN2812 at these jitter frequencies is better than what the test equipment is able to measure.
Rev. E | Page 4 of 28
Data Sheet
ADN2812
OUTPUT AND TIMING SPECIFICATIONS
Table 3.
Parameter
Conditions
Min
Typ
Max
Unit
CML OUPUT CHARACTERISTICS
(CLKOUTP/CLKOUTN, DATAOUTP/DATAOUTN)
Single-Ended Output Swing
Differential Output Swing
Output High Voltage
Output Low Voltage
CML Outputs Timing
Rise Time
VSE (see Figure 3)
VDIFF (see Figure 3)
VOH
VOL
300
600
350
700
600
1200
VCC
mV
mV
V
VCC − 0.6
VCC − 0.35 VCC − 0.3
V
20% to 80%
80% to 20%
tS (see Figure 2), OC-48
tH (see Figure 2), OC-48
95
95
200
200
112
123
250
250
ps
ps
ps
ps
Fall Time
Setup Time
Hold Time
150
150
I2C® INTERFACE DC CHARACTERISTICS
Input High Voltage
LVCMOS
VIH
0.7 VCC
V
Input Low Voltage
Input Current
VIL
0.3 VCC
+10.0
0.4
V
µA
V
VIN = 0.1 VCC or VIN = 0.9 VCC −10.0
VOL, IOL = 3.0 mA
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
See Figure 11
400
kHz
ns
ns
ns
ns
ns
ns
ns
ns
ns
tHIGH
tLOW
tHD;STA
tSU;STA
tSU;DAT
tHD;DAT
tR/tF
tSU;STO
600
1300
600
600
100
300
20 + 0.1 Cb1
600
1300
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
300
tBUF
Optional lock to REFCLK mode
@ REFCLKP or REFCLKN
VIL
0
V
VIH
VCC
100
V
Minimum Differential Input Drive
Reference Frequency
Required Accuracy
mV p-p
MHz
ppm
12.3
2.0
200
100
LVTTL DC INPUT CHARACTERISTICS
Input High Voltage
VIH
V
Input Low Voltage
Input High Current
Input Low Current
VIL
0.8
5
V
µA
µA
IIH, VIN = 2.4 V
IIL, VIN = 0.4 V
−5
LVTTL DC OUTPUT CHARACTERISTICS
Output High Voltage
Output Low Voltage
VOH, IOH = −2.0 mA
VOL, IOL = +2.0 mA
2.4
V
V
0.4
1 Cb = total capacitance of one bus line in pF. If mixed with HS mode devices, faster fall-times are allowed (see Table 6).
Rev. E | Page 5 of 28
ADN2812
Data Sheet
ABSOLUTE MAXIMUM RATINGS
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
TA = TMIN to TMAX, VCC = VMIN to VMAX, VEE = 0 V, CF = 0.47 µF,
SLICEP = SLICEN = VEE, unless otherwise noted.
Table 4.
Parameter
Rating
Supply Voltage (VCC)
4.2 V
Minimum Input Voltage (All Inputs)
Maximum Input Voltage (All Inputs)
Maximum Junction Temperature
Storage Temperature
VEE − 0.4 V
VCC + 0.4 V
125°C
−65°C to +150°C
300°C
THERMAL CHARACTERISTICS
Thermal Resistance
32-LFCSP, 4-layer board with exposed paddle soldered to VEE
Lead Temperature (Soldering 10 s)
θ
JA = 28°C/W.
ESD CAUTION
Rev. E | Page 6 of 28
Data Sheet
ADN2812
TIMING CHARACTERISTICS
CLKOUTP
T
H
T
S
DATAOUTP/N
Figure 2. Output Timing
OUTP
V
V
SE
CML
OUTN
OUTP – OUTN
V
SE
V
DIFF
0V
Figure 3. Single-Ended vs. Differential Output Specifications
Rev. E | Page 7 of 28
ADN2812
Data Sheet
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
VCC 1
VCC 2
VREF 3
NIN4
24 VCC
23 VEE
22 LOS
21 SDA
20 SCK
19 SADDR5
18 VCC
17 VEE
PIN 1
INDIC ATOR
ADN2812*
PIN5
TOP VIEW
(Not to Scale)
SLICEP 6
SLICEN7
VEE 8
* THERE IS AN EXPOSED PAD ON THE BOTTOM OF
THE PACKAGE THAT MUST BE CONNECTED TO GND.
Figure 4. Pin Configuration
Table 5. Pin Function Descriptions
Pin No.
Mnemonic
Type1
AI
Description
1
VCC
Connect to VCC.
2
VCC
P
Power for Limamp, LOS.
3
4
5
6
7
8
VREF
NIN
PIN
SLICEP
SLICEN
VEE
AO
AI
AI
AI
AI
Internal VREF Voltage. Decouple to GND with a 0.1 µF capacitor.
Differential Data Input. CML.
Differential Data Input. CML.
Differential Slice Level Adjust Input.
Differential Slice Level Adjust Input.
GND for Limamp, LOS.
P
9
10
11
12
THRADJ
REFCLKP
REFCLKN
VCC
AI
LOS Threshold Setting Resistor.
Differential REFCLK Input. 12.3 MHz to 200 MHz.
Differential REFCLK Input. 12.3 MHz to 200 MHz.
VCO Power.
DI
DI
P
13
VEE
P
VCO GND.
14
15
CF2
CF1
AO
AO
DO
P
Frequency Loop Capacitor.
Frequency Loop Capacitor.
16
17
LOL
VEE
Loss of Lock Indicator. LVTTL active high.
FLL Detector GND.
18
VCC
P
FLL Detector Power.
19
20
21
22
23
24
SADDR5
SCK
SDA
LOS
VEE
DI
DI
DI
DO
P
Slave Address Bit 5.
I2C Clock Input.
I2C Data Input.
Loss of Signal Detect Output. Active high. LVTTL.
Output Buffer, I2C GND.
Output Buffer, I2C Power.
VCC
P
25
26
27
28
29
30
CLKOUTN
CLKOUTP
SQUELCH
DATAOUTN
DATAOUTP
VEE
DO
DO
DI
DO
DO
P
Differential Recovered Clock Output. CML.
Differential Recovered Clock Output. CML.
Disable Clock and Data Outputs. Active high. LVTLL.
Differential Recovered Data Output. CML.
Differential Recovered Data Output. CML.
Phase Detector, Phase Shifter GND.
Phase Detector, Phase Shifter Power.
Connect to VCC.
31
32
VCC
VCC
P
AI
Exposed Pad
Pad
P
Connect to GND. Works as a heat sink.
1 P = power, AI = analog input, AO = analog output, DI = digital input, DO = digital output.
Rev. E | Page 8 of 28
Data Sheet
ADN2812
TYPICAL PERFORMANCE CHARACTERISTICS
16
14
12
10
8
1000
100
10
ADN2812 TOLERANCE
SONET REQUIREMENT MASK
SONET OBJECTIVE MASK
EQUIPMENT LIMIT
6
1
4
2
0.1
1
10
100
R
1k
(Ω)
10k
100k
1
10
100
1k
10k
100k
1M
10M
100M
Thresh
JITTER FREQUENCY (Hz)
Figure 5. LOS Comparator Trip Point Programming
Figure 6. Typical Measured Jitter Tolerance OC-48
Rev. E | Page 9 of 28
ADN2812
Data Sheet
I2C INTERFACE TIMING AND INTERNAL REGISTER DESCRIPTION
R/W
SLAVE ADDRESS [6:0]
A5
CTRL.
1
0
0
0
0
0
X
MSB = 1 SET BY
PIN 19
0 = WR
1 = RD
Figure 7. Slave Address Configuration
S
SLAVE ADDR, LSB = 0 (WR) A(S) SUB ADDR A(S) DATA A(S)
DATA A(S)
P
Figure 8. I2C Write Data Transfer
S
SLAVE ADDR, LSB = 0 (WR) A(S) SUB ADDR A(S)
S
SLAVE ADDR, LSB = 1 (RD) A(S) DATA A(M)
DATA A(M) P
S = START BIT
P = STOP BIT
A(M) = LACK OF ACKNOWLEDGE BY MASTER
A(S) = ACKNOWLEDGE BY SLAVE
A(M) = ACKNOWLEDGE BY MASTER
Figure 9. I2C Read Data Transfer
START BIT
STOP BIT
SLAVE ADDRESS
SUB ADDRESS
DATA
SDA
SCK
A6
A5
A7
A0
D7
D0
S
P
WR
ACK
ACK
ACK
SLADDR[4...0]
SUB ADDR[6:1]
DATA[6:1]
Figure 10. I2C Data Transfer Timing
tF
tSU;DAT
tHD;STA
tBUF
tR
SDA
SCK
tSU;STO
tR
tF
tLOW
tHIGH
tHD;STA
tSU;STA
S
S
P
S
tHD;DAT
Figure 11. I2C Port Timing Diagram
Rev. E | Page 10 of 28
Data Sheet
ADN2812
Table 6. Internal Register Map1
Reg. Name
FREQ0
FREQ1
FREQ2
RATE
R/W
Address
D7
MSB
MSB
0
D6
D5
D4
D3
D2
D1
D0
LSB
R
0x00
R
0x01
LSB
R
0x02
MSB
LSB
R
0x03
COARSE_RD[8] MSB
Coarse data rate readback
COARSE_RD[1]
MISC
R
0x04
x
x
LOS
status
Static
LOL
LOL
status
Data rate
measure
complete
x
COARSE_
RD[0] LSB
CTRLA
W
0x08
FREF range
Data rate/DIV_FREF ratio
Measure
data rate
Lock to
reference
CTRLA_RD
CTRLB
R
0x05
0x09
Readback CTRLA contents
W
Config
LOL
Reset
MISC[4]
System
reset
0
Reset
0
0
0
0
MISC[2]
CTRLB_RD
CTRLC
R
0x06
0x11
Readback CTRLBcontents
Config LOS
W
0
0
0
0
0
Squelch
mode
1 All writeable registers default to 0x00.
Table 7. Miscellaneous Register, MISC
Data Rate Measurement
Complete
Coarse Rate
Readback LSB
LOS Status
D7 D6 D5
Static LOL
D4
LOL Status
D3
D2
D1
D0
x
x
0 = No loss of signal
1 = Loss of signal
0 = Waiting for next LOL
1 = Static LOL until reset
0 = Locked
1 = Acquiring
0 = Measuring data rate
1 = Measurement complete
x
COARSE_RD[0]
Table 8. Control Register, CTRLA1
FREF Range
Data Rate/DIV_FREF Ratio
D5 D4 D3 D2
Measure Data Rate
D1
Lock to Reference
D0
D7 D6
0
0
1
1
0
1
0
1
12.3 MHz to 25 MHz
25 MHz to 50 MHz
50 MHz to 100 MHz
100 MHz to 200 MHz
0
0
0
0
0
0
0
0
1
0
1
0
1
2
4
2n
Set to 1 to measure data rate
0 = Lock to input data
1 = Lock to reference clock
n
1
0
0
0
256
1 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
Reset MISC[4]
System Reset
D5
Reset MISC[2]
D3
D7
D6
D4
D2
D1
D0
0 = LOL pin normal operation Write a 1 followed by Write a 1 followed by Set
1 = LOL pin is static LOL
0 to reset MISC[4] 0 to reset ADN2812 to 0
Write a 1 followed by Set
Set
to 0
Set
to 0
0 to reset MISC[2]
to 0
Table 10. Control Register, CTRLC
Config LOS
D2
Squelch Mode
D1
D7
D6
D5
D4
D3
D0
Set to 0
Set to 0
Set to 0
Set to 0
Set to 0
Set to 0
0 = Active high LOS
1 = Active low LOS
0 = Squelch CLK and DATA
1 = Squelch CLK or DATA
Rev. E | Page 11 of 28
ADN2812
Data Sheet
TERMINOLOGY
INPUT SENSITIVITY AND INPUT OVERDRIVE
10mV p-p
VREF
SCOPE
PROBE
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 12. For sufficiently large positive input voltage,
the output is always at Logic Level 1 and, similarly for negative
inputs, the output is always at Logic Level 0. However, the
output transitions between Logic Level 1 and Logic Level 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 magni-
tude of signal required to guarantee the correct logic level with
1 × 10−10 confidence level.
ADN2812
PIN
+
QUANTIZER
–
50Ω 50Ω
3kΩ
VREF
2.5V
Figure 13. Single-Ended Sensitivity Measurement
While driving the ADN2812 differentially (see Figure 14), sen-
sitivity 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
ADN2812 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.
OUTPUT
NOISE
1
5mV p-p
SCOPE
PROBE
VREF
0
PIN
NIN
OFFSET
OVERDRIVE
INPUT (V p-p)
+
QUANTIZER
–
SENSITIVITY
⋅ OVERDRIVE)
(2
Figure 12. Input Sensitivity and Input Overdrive
50Ω 50Ω
VREF
5mV p-p
VREF
SINGLE-ENDED VS. DIFFERENTIAL
2.5V
3kΩ
AC coupling is typically used to drive the inputs to the quan-
tizer. The inputs are internally dc biased to a common-mode
potential of ~2.5 V. Driving the ADN2812 single-ended and
observing the quantizer input with an oscilloscope probe at the
point indicated in Figure 13 show 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 13, because both positive and negative offsets need to
be accommodated, the sensitivity is twice the overdrive. The
ADN2812 quantizer typically has 6 mV p-p sensitivity.
Figure 14. Differential Sensitivity Measurement
LOS RESPONSE TIME
Loss of signal (LOS) response time is the delay between
removal of the input signal and indication of LOS at the LOS
output, Pin 22. When the inputs are dc-coupled, the LOS assert
time of the AD2812 is 500 ns typically and the deassert 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. E | Page 12 of 28
Data Sheet
ADN2812
JITTER SPECIFICATIONS
The ADN2812 CDR is designed to achieve the best bit-error-
rate (BER) performance and exceeds the jitter transfer, generation,
and tolerance specifications proposed for SONET/SDH equip-
ment defined in the Telcordia Technologies GR-253-CORE
document.
0.1
SLOPE = –20dB/DECADE
ACCEPTABLE
RANGE
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.
fC
JITTER FREQUENCY (kHz)
The following sections briefly summarize the specifications
of jitter generation, jitter transfer, and jitter tolerance in
accordance with the GR-253-CORE from Telcordia for the
optical interface at the equipment level and the ADN2812
performance with respect to those specifications.
Figure 15. 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 to ensure that no addi-
tional penalty is incurred under the operating conditions (see
Figure 16).
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.
15.00
SLOPE = –20dB/DECADE
1.50
0.15
JITTER TRANSFER
The jitter transfer function is the ratio of the jitter on the output
signal to the jitter applied on the input signal vs. 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 15).
f0
f1
f2
f3
f4
JITTER FREQUENCY (kHz)
Figure 16. SONET Jitter Tolerance Mask
Rev. E | Page 13 of 28
ADN2812
Data Sheet
THEORY OF OPERATION
The ADN2812 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 that 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.
psh
e(s)
X(s)
INPUT
DATA
d/sc
o/s
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)
=
cn
do
n psh
2
s
+ s
+ 1
o
TRACKING ERROR TRANSFER FUNCTION
2
e(s)
X(s)
s
=
d psh do
2
s
+ s +
c
cn
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 a 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.
Figure 17. PLL/DLL Architecture
JITTER PEAKING
IN ORDINARY PLL
Another view of the circuit is that the phase shifter implements
the zero required for frequency compensation of a second-order,
phase-locked loop. 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.
ADN2812
Z(s)
X(s)
o
d psh
c
n psh
FREQUENCY (kHz)
Figure 18. Jitter Response vs. Conventional PLL
The delay- and phase-loops together simultaneously provide
wide-band jitter accommodation and narrow-band jitter filter-
ing. The linearized block diagram in Figure 17 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 18), making this circuit ideal for signal regenerator
applications, where jitter peaking in a cascade of regenerators
can contribute to hazardous jitter accumulation.
The delay- and phase-loops contribute to overall jitter accom-
modation. 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.
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.
Rev. E | Page 14 of 28
Data Sheet
ADN2812
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, 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.
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 cannot be
tolerated. In this region, the gain of the integrator determines
the jitter accommodation. Because the gain of the loop integra-
tor 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.
Rev. E | Page 15 of 28
ADN2812
Data Sheet
FUNCTIONAL DESCRIPTION
value is illustrated in Figure 5. If the input level to the ADN2812
drops below the programmed LOS threshold, the output of the
LOS detector, LOS (Pin 22), 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.
FREQUENCY ACQUISITION
The ADN2812 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 acquisi-
tion. 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 deasserted.
Typically, 6 dB of electrical hysteresis is 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 increases to 6 dB (2×) above the LOS
threshold (see Figure 19).
LOS OUTPUT
Once LOL is deasserted, 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.
INPUT LEVEL
The frequency loop requires a single external capacitor between
CF2 and CF1 (Pin 14 and Pin 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 µF capacitor should be greater than 300 MΩ.
HYSTERESIS
LOS THRESHOLD
t
Figure 19. LOS Detector Hysteresis
LIMITING AMPLIFIER
The LOS detector and the SLICE level adjust can be used simul-
taneously on the ADN2812. 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.
The limiting amplifier 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 28,
Figure 29, and Figure 30). 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.
LOCK DETECTOR OPERATION
The lock detector on the ADN2812 has three modes of operation:
normal mode, REFCLK mode, and static LOL mode.
Normal Mode
In normal mode, the ADN2812 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 deasserts the loss of
lock signal appearing on LOL (Pin 16) when the VCO is 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 20.
SLICE ADJUST
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 the SLICEP/SLICEN inputs. If no adjustment
of the slice level is needed, SLICEP/SLICEN should be tied to
VEE. The gain of the slice adjustment is ~0.1 V/V.
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-vs.-resistor
Rev. E | Page 16 of 28
Data Sheet
ADN2812
LOL
HARMONIC DETECTOR
1
The ADN2812 provides a harmonic detector, which detects
whether the input data has changed to a lower harmonic of the
data rate onto which the VCO is currently locked. 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 per-
ceived by the ADN2812 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.
–1000
–250
0
250
1000
f
ERROR
VCO
(ppm)
Figure 20. Transfer Function of LOL
LOL Detector Operation Using a Reference Clock
(REFCLK Mode)
In REFCLK mode, a reference clock is used as an acquisition
aid to lock the ADN2812 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 LOL (Pin 16), is deas-
serted 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 reasserted and
control returns to the frequency loop, which reacquires 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 20.
The ADN2812 implements a harmonic detector that automati-
cally identifies whether the input data has switched to a lower
harmonic of the data rate onto which the VCO is currently
locked. When a harmonic is identified, the LOL pin is asserted
and a new frequency acquisition is initiated. The ADN2812
automatically locks onto the new data rate, and the LOL pin
is deasserted.
However, the harmonic detector does not detect higher har-
monics of the data rate. If the input data rate switches to a
higher harmonic of the data rate that the VCO is currently
locked onto, the VCO loses lock, the LOL pin is asserted,
and a new frequency acquisition is initiated. The ADN2812
automatically locks onto the new data rate.
The time to detect lock to harmonic is
16,384 × (T
d/ρ)
where:
Static LOL Mode
1/Td is the new data rate. For example, if the data rate is
The ADN2812 implements a static LOL feature, which indicates
if a loss of lock condition has ever occurred and remains asserted,
even if the ADN2812 regains lock, until the static LOL bit is manu-
ally 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 ADN2812 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 deasserted
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 ADN2812
is in acquisition mode and deasserts when the ADN2812 has
reacquired lock.
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 ADN2812 is placed in lock to reference mode,
the harmonic detector is disabled.
SQUELCH MODE
Two squelch modes are available with the ADN2812.
Squelch DATAOUT and CLKOUT mode is selected
when CTRLC[1] = 0 (default mode). In this mode, when
the squelch input (Pin 27) is driven to a TTL high state,
both the clock and data outputs are set to the zero state to
suppress downstream processing. If the squelch function
is not required, Pin 27 should be tied to VEE.
Squelch DATAOUT or CLKOUT mode is selected when
CTRLC[1] is 1. In this mode, when the squelch input is
driven to a high state, the DATAOUT pins are squelched.
When the squelch input is driven to a low state, the CLKOUT
pins are squelched. This is especially useful in repeater appli-
cations, where the recovered clock may not be needed.
Rev. E | Page 17 of 28
ADN2812
Data Sheet
I2C INTERFACE
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 8 and Figure 9 for
sample write and read data transfers and Figure 10 for a more
detailed timing diagram.
The ADN2812 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 ADN2812 has two possible 7-bit slave
addresses for both read and write operations. The MSB of the
7-bit slave address is factory programmed to 1. B5 of the slave
address is set by Pin 19, SADDR5. Slave address Bits[4:0] are
defaulted to all 0s. The slave address consists of the 7 MSBs
of an 8-bit word. The LSB of the word sets either a read or
write operation (see Figure 7). Logic 1 corresponds to a read
operation, while Logic 0 corresponds to a write operation.
REFERENCE CLOCK (OPTIONAL)
A reference clock is not required to perform clock and data
recovery with the ADN2812. 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, 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 21 through Figure 23 for sample
configurations.
To control the device on the bus, the following protocol must be
followed. 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 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.
ADN2812
REFCLKP
10
BUFFER
11
REFCLKN
100kΩ 100kΩ
VCC/2
Figure 21. Differential REFCLK Configuration
The ADN2812 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 ADN2812 has 8 subaddresses to enable
the user-accessible internal registers (see Table 1 through Table 7).
Therefore, it 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 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.
VCC
ADN2812
REFCLKP
CLK
OSC
OUT
BUFFER
REFCLKN
100kΩ 100kΩ
VCC/2
Figure 22. Single-Ended REFCLK Configuration
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, they cause an imme-
diate 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 ADN2812 does not issue an acknowledge and returns to
the idle condition. If the user exceeds the highest subaddress
while reading back in autoincrement mode, the highest
VCC
ADN2812
10
REFCLKP
BUFFER
11
NC
REFCLKN
100kΩ 100kΩ
VCC/2
Figure 23. No REFCLK Configuration
Rev. E | Page 18 of 28
Data Sheet
ADN2812
The two uses of the reference clock are mutually exclusive. The
reference clock can be used either as an acquisition aid for the
ADN2812 to lock onto data or to measure the frequency of the
incoming data to within 0.01%. (There is the capability to meas-
ure 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 the exact data rate and wants to
force the part to lock onto only that data rate; in the second use,
the user does not know the data rate 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.
The user can specify a fixed integer multiple of the reference
clock to lock onto using CTRLA[5:2], where CTRLA is set to
the data rate/DIV_FREF and 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 is 38.88 MHz
and the input data rate is 622.08 Mb/s, CTRLA[7:6] is set to
[01] to give a divided-down reference clock of 19.44 MHz.
CTRLA[5:2] is set to [0101], that is, 5, because
622.08 Mb/s/19.44 MHz = 25
In this mode, if the ADN2812 loses lock for any reason, it
relocks onto the reference clock and continues to output a
stable clock.
While the ADN2812 is operating in LTR 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 1
to 0 transition into the CTRLB[5] bit to initiate a new frequency
acquisition.
Using the Reference Clock to Lock onto Data
Writing CTRLA[0] = 1 puts the ADN2812 into lock-to-REFCLK
(LTR) mode. In this mode, the ADN2812 locks onto a fre-
quency derived from the reference clock according to the
following equation:
A frequency acquisition can also be initiated in LTR mode
by writing a 0 to 1 transition into CTRLA[0]; however, it is
recommended that a frequency acquisition be initiated by
writing a 1 to 0 transition into CTRLB[5] as previously
explained.
Data Rate/2CTRLA[5:2] = REFCLK/2CTRLA[7:6]
The user must know exactly what the data rate is and provide
a reference clock that is a function of this rate. The ADN2812
can still be used as a continuous rate device in this configu-
ration, provided that the user has the ability to provide a
reference clock that has a variable frequency (see the Appli-
cation Note AN-632).
Using the Reference Clock to Measure Data Frequency
The user can also provide a reference clock to measure the
recovered data frequency, in which case the ADN2812 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 ADN2812 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 be anywhere between 12.3 MHz and
200 MHz. By default, the ADN2812 expects a reference clock
between 12.3 MHz and 25 MHz. 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 ADN2812 to use the correct
reference frequency range by setting two bits of the CTRLA
register, CTRLA[7:6].
The reference clock can range from 12.3 MHz to 200 MHz.
The ADN2812 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 ADN2812 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.
Table 11. CTRLA[7:6] Settings
CTRLA[7:6]
Range (MHz)
12.3 to 25
25 to 50
50 to 100
100 to 200
00
01
10
11
Table 12. CTRLA[5:2] Settings
CTRLA[5:2]
Ratio
0000
1
0001
n
2
2n
1000
256
Rev. E | Page 19 of 28
ADN2812
Data Sheet
Prior to reading back the data rate using the reference clock,
Control Register CTRLA Bits[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:
(OC-48). After following Step 1 through Step 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)
= 2.488Gb/s
If subsequent frequency measurements are required, CTRLA[1]
should remain set to 1. It does not need to be reset. The meas-
urement process is reset by writing a 1 followed by a 0 to
CTRLB[3]. This initiates a new data rate measurement.
Follow Step 2 through Step 4 to read back the new data rate.
1. Write a 1 to CTRLA[1]. This enables the fine data rate
measurement capability of the ADN2812. This bit is
level-sensitive and does not need to be reset to perform
subsequent frequency measurements.
2. Reset MISC[2] by writing a 1 followed by a 0 to CTRLB[3].
This initiates a new data rate measurement.
Note that a data rate readback is valid only if LOL is low. If LOL
is high, the data rate readback is invalid.
Additional Features Available via the I2C Interface
Coarse Data Rate Readback
The data rate can be read back over the I2C interface to approxi-
mately 10% without the need of an external reference clock. A
9-bit register, COARSE_RD[8:0], can be read back when LOL
is deasserted. 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 14 provides coarse data rate readback to
within 10%.
3. Read back MISC[2]. If it is 0, the measurement is not
complete. If it is 1, 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.
4. Read back the data rate from Register FREQ2[6:0],
Register FREQ1[7:0], and Register FREQ0[7:0].
Use the following equation to determine the data rate:
f
DATARATE = (FREQ[22:0] × fREFCLK)/2(14 + SEL_RATE)
where:
LOS Configuration
FREQ[22:0] is the reading from FREQ2[6:0] (MSByte),
FREQ1[7:0], and FREQ0[7:0] (LSByte).
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.
f
f
DATARATE is the data rate (Mb/s).
REFCLK is the REFCLK frequency (MHz).
SEL_RATE is the setting from CTRLA[7:6].
Table 13.
D22 D21...D17 D16 D15 D14...D9 D8 D7 D6...D1 D0
System Reset
FREQ2[6:0]
FREQ1[7:0]
FREQ0[7:0]
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 ADN2812 in the
operating mode that it was previously programmed to in
Register CTRL[A], Register CTRL[B], and Register CTRL[C].
For example, if the reference clock frequency is 32 MHz,
SEL_RATE = 1, because the CTRLA[7:6] setting is [01] and
the reference frequency falls into the 25 MHz to 50 MHz range.
Assume for this example that the input data rate is 2.488 Gb/s
Rev. E | Page 20 of 28
Data Sheet
ADN2812
APPLICATIONS INFORMATION
If connections to the supply and ground are made through vias,
the use of multiple vias in parallel helps to reduce series induc-
tance, especially on Pin 24, which supplies power to the high
speed CLKOUTP/CLKOUTN and DATAOUTP/DATAOUTN
output buffers. Refer to the schematic in Figure 24 for recom-
mended connections.
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, especially on Pin 23, which is the ground return
for the output buffers. 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
C
plane = 0.88εr 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 and 0.25 mm spacing, C ~15 pF/cm2.
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
and as close as possible to the ADN2812 VCC pins.
VCC
50Ω
100Ω × 4
TRANSMISSION LINES
DATAOUTP
DATAOUTN
CLKOUTP
CLKOUTN
VCC
+
0.1µF
1nF
10µF
32 31 30 29 28 27 26 25
24
VCC
VCC
VCC
VCC
1
2
3
4
5
6
7
8
1nF
0.1µF
VEE
23
22
21
20
19
18
17
VREF
NIN
LOS
0.1µF
1nF
µC
EXPOSED PAD
TIED OFF TO
VEE PLANE
WITH VIAS
SDA
SCK
2
VCC
I C
0.1µF
PIN
CONTROLLER
SLICEP
SLICEN
VEE
SADDR5
VCC
50Ω
50Ω
C
C
IN
VEE
TIA
VCC
9
10 11 12 13 14 15 16
IN
1nF
0.1µF
µC
R
TH
0.47µF
±
20% >300MΩ
INSULATION RESISTANCE
NC
VCC
NC = NO CONNECT
0.1µF
1nF
Figure 24. Typical Applications Circuit
Rev. E | Page 21 of 28
ADN2812
Data Sheet
that the solder joint size is maximized. The bottom of the chip
scale 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.
Transmission Lines
Use of 50 Ω transmission lines is required for all high frequency
input and output signals to minimize reflections: PIN, NIN,
CLKOUTP, CLKOUTN, DATAOUTP, DATAOUTN (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 CLKOUTP/
CLKOUTN and DATAOUTP/DATAOUTN output traces to
be matched in length to avoid skew between the differential
traces. All high speed CML outputs, CLKOUTP/CLKOUTN
and DATAOUTP/DATAOUTN, 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 25).
Choosing AC Coupling Capacitors
AC coupling capacitors at the inputs (PIN, NIN) and outputs
(DATAOUTP, DATAOUTN) of the ADN2812 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 27), causing pattern-
dependent jitter (PDJ).
The high speed inputs, PIN and NIN, are internally terminated
with 50 Ω to an internal reference voltage (see Figure 26). A 0.1 µF
is recommended between VREF (Pin 3) and GND to provide an
ac ground for the inputs.
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.
As with any high speed mixed-signal design, take care to keep
all high speed digital traces away from sensitive analog nodes.
For example, assuming that 2% droop can be tolerated, then the
maximum differential droop is 4%. Normalizing to Vpp
V
TERM
VCC
VCC
Droop = ∆ V = 0.04 V = 0.5 Vpp (1 − e–t/τ); therefore, τ = 12t
50Ω
50Ω
100Ω 100Ω
100Ω 100Ω
0.1µF
0.1µF
where:
τ is the RC time constant (C is the ac coupling capacitor,
R = 100 Ω seen by C).
50Ω
t is the total discharge time, which is equal to nΤ.
n is the number of CIDs.
50Ω
ADN2812
T is the bit period.
V
TERM
The capacitor value can then be calculated by combining the
equations for τ and t
Figure 25. Typical ADN2812 Applications Circuit
VCC
C =12nT/R
ADN2812
C
C
50Ω
50Ω
IN
IN
PIN
NIN
Once the capacitor value is selected, the PDJ can be
approximated as
TIA
1/e(
/0.6
/nT/RC
)
PDJ pspp = 0.5tr
50Ω 50Ω
3kΩ
VREF
where:
2.5V
PDJpspp is the amount of pattern-dependent jitter allowed;
< 0.01 UI p-p typical.
0.1µF
tr is the rise time, which is equal to 0.22/BW, where BW is ~ 0.7
(bit rate). This expression for tr is accurate only for the inputs.
The output rise time for the ADN2812 is ~100 ps regardless of
data rate.
Figure 26. ADN2812 AC-Coupled Input Configuration
Soldering Guidelines for Chip Scale Package
The leads on the 32-lead LFCSP are rectangular. The printed
circuit board pad for these should be 0.1 mm longer than the
package lead length and 0.05 mm wider than the package lead
width. The lead should be centered on the pad. This ensures
Rev. E | Page 22 of 28
Data Sheet
ADN2812
VCC
ADN2812
C
C
IN
V1
V2
PIN
C
C
OUT
+
DATAOUTP
DATAOUTN
50Ω
CDR
TIA
LIMAMP
VREF
IN
V1b
V2b
50Ω
NIN
–
OUT
1
2
3
4
V1
V1b
V2
VREF
V2b
VTH
V
DIFF
V
= V2–V2b
DIFF
VTH = ADN2812 QUANTIZER THRESHOLD
NOTES:
1. DURING DATA PATTERNS WITH HIGH TRANSITION DENSITY, DIFFERENTIAL DC VOLTAGE AT V1 AND V2 IS ZERO.
2. WHEN THE OUTPUT OF THE TIA GOES TO CID, V1 AND V1b ARE DRIVEN TO DIFFERENT DC LEVELS. V2AND V2b DISCHARGE TO THE
VREF LEVEL, WHICH EFFECTIVELY INTRODUCES A DIFFERENTIAL DC OFFSET ACROSS THE AC COUPLING CAPACITORS.
3. WHEN THE BURST OF DATA STARTS AGAIN, THE DIFFERENTIAL DC OFFSET ACROSS THE AC COUPLING CAPACITORS IS APPLIED TO
THE INPUT LEVELS CAUSING A DC SHIFT IN THE DIFFERENTIAL INPUT. THIS SHIFT IS LARGE ENOUGH SUCH THAT ONE OF THE STATES,
EITHER HIGH OR LOW DEPENDING ON THE LEVELS OF V1AND V1b WHEN THE TIA WENT TO CID, IS CANCELED OUT. THE QUANTIZER
DOES NOT RECOGNIZE THISAS A VALID STATE.
4. THE DC OFFSET SLOWLY DISCHARGES UNTIL THE DIFFERENTIAL INPUT VOLTAGE EXCEEDS THE SENSITIVITY OF THE ADN2812. THE
QUANTIZER CAN RECOGNIZE BOTH HIGH AND LOW STATES AT THIS POINT.
Figure 27. Example of Baseline Wander
DC-COUPLED APPLICATION
The inputs to the ADN2812 can 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 ADN2812 are dc-coupled, care must be taken not to
violate the input range and common-mode level requirements
of the ADN2812 (see Figure 28 through Figure 30). If dc coupling
is required, and the output levels of the TIA do not adhere to
the levels shown in Figure 29, level shifting and/or an attenuator
must be between the TIA outputs and the ADN2812 inputs.
VCC
PIN
NIN
V
= PIN – NIN = 2 × V = 10mV AT SENSITIVITY
SE
PP
V
= 5mV MIN
SE
V
= 2.3V MIN
CM
(DC-COUPLED)
Figure 29. Minimum Allowed DC-Coupled Input Levels
ADN2812
50Ω
50Ω
PIN
V
= PIN – NIN = 2 × V = 2.0V MAX
SE
PP
PIN
TIA
NIN
V
= 1.0V MAX
SE
50Ω 50Ω
3kΩ
VREF
V
= 2.3V
CM
(DC-COUPLED)
2.5V
0.1µF
NIN
Figure 28. DC-Coupled Application
Figure 30. Maximum Allowed DC-Coupled Input Levels
Rev. E | Page 23 of 28
ADN2812
Data Sheet
COARSE DATA RATE READBACK LOOK-UP TABLE
Code is the 9-bit value read back from COARSE_RD[8:0].
Table 14.
Code
FMID
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
Code
96
97
98
99
FMID
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
0
1
2
3
4
5
6
7
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
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
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
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
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
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
Rev. E | Page 24 of 28
Data Sheet
ADN2812
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
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
FMID
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
FMID
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
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
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
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
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
Rev. E | Page 25 of 28
ADN2812
Data Sheet
OUTLINE DIMENSIONS
5.10
5.00 SQ
4.90
0.30
0.25
0.18
PIN 1
INDICATOR
PIN 1
25
24
32
1
INDICATOR
0.50
BSC
3.25
3.10 SQ
2.95
EXPOSED
PAD
17
16
8
9
0.50
0.40
0.30
0.25 MIN
TOP VIEW
BOTTOM VIEW
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
0.80
0.75
0.70
0.05 MAX
0.02 NOM
SECTION OF THIS DATA SHEET.
COPLANARITY
0.08
0.20 REF
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MO-220-WHHD.
Figure 31. 32-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
5 mm × 5 mm Body, Very Thin Quad
(CP-32-7)
Dimensions shown in millimeters
ORDERING GUIDE
Model1
Temperature Range
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
Package Description
Package Option
ADN2812ACPZ
ADN2812ACPZ-RL
ADN2812ACPZ-RL7
EVAL-ADN2812EBZ
32-Lead LFCSP_WQ
CP-32-7
CP-32-7
CP-32-7
32-Lead LFCSP_WQ, 13”Tape-Reel, 5000 pcs
32-Lead LFCSP_WQ, 7” Tape-Reel, 1500 pcs
Evaluation Board
1 Z = RoHS Compliant Part.
Rev. E | Page 26 of 28
Data Sheet
NOTES
ADN2812
Rev. E | Page 27 of 28
ADN2812
NOTES
Data Sheet
I2C refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors).
©2004–2012 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D04228-0-3/12(E)
Rev. E | Page 28 of 28
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