ADC08D500CIYB/NOPB [TI]

8 位、双路 500MSPS 或单路 1.0GSPS 模数转换器 (ADC) | NNB | 128 | -40 to 85;
ADC08D500CIYB/NOPB
型号: ADC08D500CIYB/NOPB
厂家: TEXAS INSTRUMENTS    TEXAS INSTRUMENTS
描述:

8 位、双路 500MSPS 或单路 1.0GSPS 模数转换器 (ADC) | NNB | 128 | -40 to 85

转换器 模数转换器
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ADC08D500  
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SNAS274F MAY 2005REVISED APRIL 2013  
ADC08D500 High Performance, Low Power, Dual 8-Bit, 500 MSPS A/D Converter  
Check for Samples: ADC08D500  
1
FEATURES  
DESCRIPTION  
The ADC08D500 is  
a dual, low power, high  
2
Internal Sample-and-Hold  
performance CMOS analog-to-digital converter that  
digitizes signals to 8 bits resolution at sampling rates  
up to 500 MSPS. Consuming a typical 1.4 Watts at  
500 MSPS from a single 1.9 Volt supply, this device  
is ensured to have no missing codes over the full  
operating temperature range. The unique folding and  
interpolating architecture, the fully differential  
comparator design, the innovative design of the  
internal sample-and-hold amplifier and the self-  
calibration scheme enable a very flat response of all  
dynamic parameters beyond Nyquist, producing a  
high 7.5 ENOB with a 250 MHz input signal and a  
500 MHz sample rate while providing a 10-18 B.E.R.  
Output formatting is offset binary and the LVDS  
digital outputs are compatible with IEEE 1596.3-1996,  
with the exception of an adjustable common mode  
voltage between 0.8V and 1.2V.  
Single +1.9V ±0.1V Operation  
Choice of SDR or DDR Output Clocking  
Interleave Mode for 2x Sampling Rate  
Multiple ADC Synchronization Capability  
Ensured No Missing Codes  
Serial Interface for Extended Control  
Fine Adjustment of Input Full-Scale Range and  
Offset  
Duty Cycle Corrected Sample Clock  
APPLICATIONS  
Direct RF Down Conversion  
Digital Oscilloscopes  
Satellite Set-Top Boxes  
Communications Systems  
Test Instrumentation  
Each converter has a 1:2 demultiplexer that feeds  
two LVDS buses and reduces the output data rate on  
each bus to half the sampling rate. The two  
converters can be interleaved and used as a single 1  
GSPS ADC.  
KEY SPECIFICATIONS  
The converter typically consumes less than 3.5 mW  
in the Power Down Mode and is available in a 128-  
lead, thermally enhanced exposed pad HLQFP and  
operates over the Industrial (-40°C TA +85°C)  
temperature range.  
Resolution 8 Bits  
Max Conversion Rate 500 MSPS (min)  
Bit Error Rate 10-18 (typ)  
ENOB @ 250 MHz Input 7.5 Bits (typ)  
DNL ±0.15 LSB (typ)  
Power Consumption  
Operating 1.4 W (typ)  
Power Down Mode 3.5 mW (typ)  
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of  
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.  
2
All trademarks are the property of their respective owners.  
PRODUCTION DATA information is current as of publication date.  
Products conform to specifications per the terms of the Texas  
Instruments standard warranty. Production processing does not  
necessarily include testing of all parameters.  
Copyright © 2005–2013, Texas Instruments Incorporated  
ADC08D500  
SNAS274F MAY 2005REVISED APRIL 2013  
www.ti.com  
Block Diagram  
I CHANNEL  
V
I+  
+
-
IN  
S/H  
DIOUT  
1:2 DEMUX  
& LATCH  
8-BIT  
ADC  
V
I-  
IN  
Data Bus Output  
16 LVDS Pairs  
DIOUTD  
INPUT  
MUX  
Q CHANNEL  
+
-
V
Q+  
Q-  
IN  
S/H  
DQOUT  
V
8-BIT  
ADC  
IN  
1:2 DEMUX  
& LATCH  
Data Bus Output  
16 LVDS Pairs  
DQOUTD  
V
V
REF  
BG  
CLK+  
CLK-  
Output  
Clock  
Generator  
DCLK+  
DCLK-  
CLK/2  
2
Control  
Inputs  
OR  
Control  
Logic  
CalRun  
Serial  
Interface  
3
2
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ADC08D500  
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SNAS274F MAY 2005REVISED APRIL 2013  
Pin Configuration  
DI2+  
96  
GND  
1
2
3
4
5
6
7
8
V
A
95  
94  
93  
92  
91  
90  
89  
88  
87  
86  
85  
84  
83  
82  
81  
80  
79  
78  
77  
76  
75  
74  
73  
72  
71  
70  
69  
68  
67  
66  
65  
DI2-  
DI3+  
DI3-  
DI4+  
DI4-  
DI5+  
DI5-  
OUTV/SCLK  
OutEdge/DDR/SDATA  
V
A
GND  
V
CMO  
V
A
V
DR  
GND  
9
V
I-  
DR GND  
DI6+  
DI6-  
DI7+  
DI7-  
DCLK+  
DCLK-  
OR-  
IN  
I+  
10  
11  
12  
V
IN  
GND  
V
A
13  
14  
15  
16  
17  
18  
19  
20  
FSR/ECE  
DCLK_RST  
V
A
ADC08D500  
V
A
OR+  
CLK+  
CLK-  
V
DQ7-  
DQ7+  
DQ6-  
DQ6+  
DR GND  
A
GND 21  
Q+  
V
22  
23  
24  
25  
26  
27  
28  
29  
30  
31  
32  
IN  
V
Q-  
IN  
*
V
DR  
GND  
V
A
DQ5-  
DQ5+  
DQ4-  
DQ4+  
DQ3-  
DQ3+  
DQ2-  
DQ2+  
PD  
GND  
V
A
PDQ  
CAL  
V
BG  
R
EXT  
* Exposed pad on back of package must be soldered to ground plane to ensure rated performance.  
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Pin Descriptions and Equivalent Circuits  
Pin Functions  
www.ti.com  
Pin No.  
Symbol  
Equivalent Circuit  
Description  
V
A
Output Voltage Amplitude and Serial Interface Clock. Tie this pin  
high for normal differential DCLK and data amplitude. Ground this  
pin for a reduced differential output amplitude and reduced power  
consumption. See The LVDS Outputs. When the extended control  
mode is enabled, this pin functions as the SCLK input which clocks  
in the serial data. See NORMAL/EXTENDED CONTROL for details  
on the extended control mode. See THE SERIAL INTERFACE for  
description of the serial interface.  
50k  
3
OutV / SCLK  
GND  
V
A
DCLK Edge Select, Double Data Rate Enable and Serial Data  
Input. This input sets the output edge of DCLK+ at which the output  
data transitions. (See OutEdge Setting). When this pin is floating or  
connected to 1/2 the supply voltage, DDR clocking is enabled.  
When the extended control mode is enabled, this pin functions as  
the SDATA input. See NORMAL/EXTENDED CONTROL for details  
on the extended control mode. See THE SERIAL INTERFACE for  
description of the serial interface.  
50k  
200k  
DDR  
OutEdge / DDR /  
SDATA  
50k  
8 pF  
4
GND  
SDATA  
V
A
DCLK Reset. A positive pulse on this pin is used to reset and  
synchronize the DCLK outs of multiple converters. See MULTIPLE  
ADC SYNCHRONIZATION for detailed description.  
V
15  
26  
DCLK_RST  
PD  
A
Power Down Pins. A logic high on the PD pin puts the entire device  
into the Power Down Mode.  
Calibration Cycle Initiate. A minimum 80 input clock cycles logic low  
followed by a minimum of 80 input clock cycles high on this pin  
initiates the self calibration sequence. See Self Calibration for an  
overview of self-calibration and On-Command Calibration for a  
description of on-command calibration.  
30  
CAL  
GND  
V
A
50 kW  
A logic high on the PDQ pin puts only the "Q" ADC into the Power  
Down mode.  
29  
PDQ  
GND  
V
A
Full Scale Range Select and Extended Control Enable. In non-  
extended control mode, a logic low on this pin sets the full-scale  
differential input range to 650 mVP-P. A logic high on this pin sets  
the full-scale differential input range to 870 mVP-P. See The Analog  
Inputs. To enable the extended control mode, whereby the serial  
interface and control registers are employed, allow this pin to float  
or connect it to a voltage equal to VA/2. See NORMAL/EXTENDED  
CONTROL for information on the extended control mode.  
50k  
50k  
200k  
8 pF  
14  
FSR/ECE  
GND  
4
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Pin Functions  
Pin No.  
Symbol  
Equivalent Circuit  
Description  
V
A
Calibration Delay, Dual Edge Sampling and Serial Interface Chip  
Select. With a logic high or low on pin 14, this pin functions as  
Calibration Delay and sets the number of clock cycles after power  
up before calibration begins (See Self-Calibration). With pin 14  
floating, this pin acts as the enable pin for the serial interface input  
and the CalDly value becomes 0b (short delay with no provision for  
a long power-up calibration delay). When this pin is floating or  
connected to a voltage equal to VA/2, DES (Dual Edge Sampling)  
mode is selected where the "I" input is sampled at twice the clock  
rate and the "Q" input is ignored. See Dual-Edge Sampling.  
50k  
50k  
CalDly / DES /  
SCS  
127  
GND  
V
A
LVDS Clock input pins for the ADC. The differential clock signal  
must be a.c. coupled to these pins. The input signal is sampled on  
the falling edge of CLK+. See Acquiring the Input for a description  
of acquiring the input and THE CLOCK INPUTS for an overview of  
the clock inputs.  
18  
19  
CLK+  
CLK-  
50k  
AGND  
100  
V
BIAS  
V
A
50k  
AGND  
V
A
50k  
11  
10  
.
22  
23  
VINI+  
VINI−  
.
VINQ+  
VINQ−  
AGND  
100  
V
CMO  
Analog signal inputs to the ADC. The differential full-scale input  
range is 650 mVP-P when the FSR pin is low, or 870 mVP-P when  
the FSR pin is high.  
Control from V  
CMO  
V
A
50k  
AGND  
V
A
V
CM  
Common Mode Voltage. This pin is the common mode output in  
d.c. coupling mode and also serves as the a.c. coupling mode  
select pin. When d.c. coupling is used, the voltage output at this pin  
200k  
8 pF  
7
VCMO  
is required to be the common mode input voltage at VIN+ and VIN−  
Enable AC  
Coupling  
when d.c. coupling is used. This pin should be grounded when a.c.  
coupling is used at the analog inputs. This pin is capable of  
sourcing or sinking 100 μA. See THE ANALOG INPUT.  
GND  
31  
VBG  
Bandgap output voltage capable of 100 μA source/sink.  
V
D
Calibration Running indication. This pin is at a logic high when  
calibration is running.  
126  
CalRun  
DGND  
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Pin Functions  
Pin No.  
Symbol  
Equivalent Circuit  
Description  
V
A
V
External bias resistor connection. Nominal value is 3.3k-Ohms  
(±0.1%) to ground. See Self-Calibration.  
32  
REXT  
GND  
Temperature Diode Positive (Anode) and Negative (Cathode).  
These pins may be used for die temperature measurements,  
however no specified accuracy is implied or ensured. Noise  
coupling from adjacent output data signals has been shown to  
affect temperature measurements using this feature. See Thermal  
Management.  
Tdiode_P  
Tdiode_N  
34  
35  
Tdiode_P  
Tdiode_N  
83 / 78  
84 / 77  
85 / 76  
86 / 75  
89 / 72  
90 / 71  
91 / 70  
92 / 69  
93 / 68  
94 / 67  
95 / 66  
96 / 65  
100 / 61  
101 / 60  
102 / 59  
103 / 58  
DI7/ DQ7−  
DI7+ / DQ7+  
DI6/ DQ6−  
DI6+ / DQ6+  
DI5/ DQ5−  
DI5+ / DQ5+  
DI4/ DQ4−  
DI4+ / DQ4+  
DI3/ DQ3−  
DI3+ / DQ3+  
DI2/ DQ2−  
DI2+ / DQ2+  
DI1/ DQ1−  
DI1+ / DQ1+  
DI0/ DQ0−  
DI0+ / DQ0+  
I and Q channel LVDS Data Outputs that are not delayed in the  
output demultiplexer. Compared with the DId and DQd outputs,  
these outputs represent the later time samples. These outputs  
should always be terminated with a 100differential resistor.  
VDR  
104 / 57  
105 / 56  
106 / 55  
107 / 54  
111 / 50  
112 / 49  
113 / 48  
114 / 47  
115 / 46  
116 / 45  
117 / 44  
118 / 43  
122 / 39  
123 / 38  
124 / 37  
125 / 36  
DId7/ DQd7−  
DId7+ / DQd7+  
DId6/ DQd6−  
DId6+ / DQd6+  
DId5/ DQd5−  
DId5+ / DQd5+  
DId4/ DQd4−  
DId4+ / DQd4+  
DId3/ DQd3−  
DId3+ / DQd3+  
DId2/ DQd2−  
DId2+ / DQd2+  
DId1/ DQd1−  
DId1+ / DQd1+  
DId0/ DQd0−  
DId0+ / DQd0+  
-
+
-
I and Q channel LVDS Data Outputs that are delayed by one CLK  
cycle in the output demultiplexer. Compared with the DI/DQ  
outputs, these outputs represent the earlier time sample. These  
outputs should always be terminated with a 100differential  
resistor.  
+
DR GND  
Out Of Range output. A differential high at these pins indicates that  
the differential input is out of range (outside the range ±325 mV or  
±435 mV as defined by the FSR pin).  
79  
80  
OR+  
OR-  
Differential Clock outputs used to latch the output data. Delayed  
and non-delayed data outputs are supplied synchronous to this  
signal. This signal is at 1/2 the input clock rate in SDR mode and at  
1/4 the input clock rate in the DDR mode. The DCLK outputs are  
not active during a calibration cycle, therefore this is not  
recommended as a system clock.  
82  
81  
DCLK+  
DCLK-  
2, 5, 8, 13,  
16, 17, 20,  
25, 28, 33,  
128  
VA  
Analog power supply pins. Bypass these pins to ground.  
6
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Pin Functions  
Pin No.  
Symbol  
Equivalent Circuit  
Description  
40, 51 ,62,  
73, 88, 99,  
110, 121  
VDR  
Output Driver power supply pins. Bypass these pins to DR GND.  
1, 6, 9, 12,  
21, 24, 27,  
41  
GND  
Ground return for VA.  
42, 53, 64,  
74, 87, 97,  
108, 119  
DR GND  
NC  
Ground return for VDR.  
52, 63, 98,  
109, 120  
No Connection. Make no connection to these pins.  
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam  
during storage or handling to prevent electrostatic damage to the MOS gates.  
(1) (2)  
Absolute Maximum Ratings  
Supply Voltage (VA, VDR  
)
2.2V  
0V to 100 mV  
Supply Difference  
VDR - VA  
Voltage on Any Input Pin  
(Except VIN+, VIN- )  
0.15V to (VA +0.15V)  
-0.15V to 2.5V  
Voltage on VIN+, VIN  
-
(Maintaining Common Mode)  
Ground Difference  
|GND - DR GND|  
0V to 100 mV  
±25 mA  
±50 mA  
2.0 W  
(3)  
Input Current at Any Pin  
(3)  
Package Input Current  
Power Dissipation at TA = 85°C  
(4)  
ESD Susceptibility  
Human Body Model  
Machine Model  
2500V  
250V  
Soldering Temperature, Infrared,  
10 seconds  
235°C  
Storage Temperature  
65°C to +150°C  
(1) All voltages are measured with respect to GND = DR GND = 0V, unless otherwise specified.  
(2) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. There is no ensure of operation at the  
Absolute Maximum Ratings. Operating Ratings indicate conditions for which the device is functional, but do not ensure specific  
performance limits. For ensured specifications and test conditions, see the Electrical Characteristics. The ensured specifications apply  
only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test  
conditions.  
(3) When the input voltage at any pin exceeds the power supply limits (that is, less than GND or greater than VA), the current at that pin  
should be limited to 25 mA. The 50 mA maximum package input current rating limits the number of pins that can safely exceed the  
power supplies with an input current of 25 mA to two. This limit is not placed upon the power, ground and digital output pins.  
(4) Human body model is 100 pF capacitor discharged through a 1.5 kresistor. Machine model is 220 pF discharged through ZERO  
Ohms.  
(1) (2)  
Operating Ratings  
Ambient Temperature Range  
40°C TA +85°C  
+1.8V to +2.0V  
+1.8V to VA  
Supply Voltage (VA)  
Driver Supply Voltage (VDR  
)
Analog Input Common Mode Voltage  
VCMO ±50mV  
(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. There is no ensure of operation at the  
Absolute Maximum Ratings. Operating Ratings indicate conditions for which the device is functional, but do not ensure specific  
performance limits. For ensured specifications and test conditions, see the Electrical Characteristics. The ensured specifications apply  
only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test  
conditions.  
(2) All voltages are measured with respect to GND = DR GND = 0V, unless otherwise specified.  
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Operating Ratings (1) (2) (continued)  
VIN+, VIN- Voltage Range (Maintaining Common Mode)  
0V to 2.15V  
(100% duty cycle)  
0V to 2.5V  
(10% duty cycle)  
Ground Difference  
(|GND - DR GND|)  
0V  
CLK Pins Voltage Range  
Differential CLK Amplitude  
0V to VA  
0.4VP-P to 2.0VP-P  
Package Thermal Resistance(1)  
Package  
θJA  
θJC (Top of Package)  
θJ-PAD (Thermal Pad)  
2.8°C / W  
128-Lead Exposed Pad  
HLQFP  
25°C / W  
10°C / W  
(1) Soldering process must comply with TI’s Reflow Temperature Profile specifications. Refer to www.ti.com/packaging.  
Converter Electrical Characteristics  
The following specifications apply after calibration for VA = VDR = +1.9VDC, OutV = 1.9V, VIN FSR (a.c. coupled) = differential  
870mVP-P, CL = 10 pF, Differential, a.c. coupled Sinewave Input Clock, fCLK = 500 MHz at 0.5VP-P with 50% duty cycle, VBG  
=
Floating, Non-Extended Control Mode, SDR Mode, REXT = 3300±0.1%, Analog Signal Source Impedance = 100Ω  
(1) (2)  
Differential. Boldface limits apply for TA = TMIN to TMAX. All other limits TA = 25°C, unless otherwise noted.  
Typical  
Limits  
Units  
(Limits)  
Symbol  
Parameter  
Conditions  
(3)  
(3)  
STATIC CONVERTER CHARACTERISTICS  
DC Coupled, 1MHz Sine Wave Over  
ranged  
INL  
Integral Non-Linearity  
±0.3  
±0.9  
LSB (max)  
DC Coupled, 1MHz Sine Wave Over  
ranged  
DNL  
Differential Non-Linearity  
Resolution with No Missing Codes  
Offset Error  
±0.15  
±0.6  
8
LSB (max)  
Bits  
1.5  
0.5  
LSB (min)  
LSB (max)  
VOFF  
-0.45  
VOFF_ADJ Input Offset Adjustment Range  
Extended Control Mode  
Extended Control Mode  
±45  
0.6  
1.31  
±20  
mV  
(4)  
PFSE  
Positive Full-Scale Error  
Negative Full-Scale Error  
±25  
±25  
±15  
mV (max)  
mV (max)  
%FS  
(4)  
NFSE  
FS_ADJ  
Full-Scale Adjustment Range  
NORMAL MODE (non DES) DYNAMIC CONVERTER CHARACTERISTICS  
FPBW Full Power Bandwidth Normal (non DES) Mode  
1.7  
GHz  
(1) The analog inputs are protected as shown below. Input voltage magnitudes beyond the Absolute Maximum Ratings may damage this  
device.  
V
A
TO INTERNAL  
CIRCUITRY  
I / O  
GND  
(2) To ensure accuracy, it is required that VA and VDR be well bypassed. Each supply pin must be decoupled with separate bypass  
capacitors. Additionally, achieving rated performance requires that the backside exposed pad be well grounded.  
(3) Typical figures are at TA = 25°C, and represent most likely parametric norms. Test limits are specified to TI's AOQL (Average Outgoing  
Quality Level).  
(4) Calculation of Full-Scale Error for this device assumes that the actual reference voltage is exactly its nominal value. Full-Scale Error for  
this device, therefore, is a combination of Full-Scale Error and Reference Voltage Error. See Figure 2. For relationship between Gain  
Error and Full-Scale Error, see Specification Definitions for Gain Error.  
8
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Converter Electrical Characteristics (continued)  
The following specifications apply after calibration for VA = VDR = +1.9VDC, OutV = 1.9V, VIN FSR (a.c. coupled) = differential  
870mVP-P, CL = 10 pF, Differential, a.c. coupled Sinewave Input Clock, fCLK = 500 MHz at 0.5VP-P with 50% duty cycle, VBG  
Floating, Non-Extended Control Mode, SDR Mode, REXT = 3300±0.1%, Analog Signal Source Impedance = 100Ω  
Differential. Boldface limits apply for TA = TMIN to TMAX. All other limits TA = 25°C, unless otherwise noted. (1) (2)  
=
Typical  
Limits  
Units  
(Limits)  
Symbol  
Parameter  
Conditions  
(3)  
(3)  
B.E.R.  
Bit Error Rate  
Gain Flatness  
10-18  
±0.5  
7.5  
7.5  
7.5  
47  
Error/Sample  
dBFS  
Bits  
d.c. to 500 MHz  
fIN = 50 MHz, VIN = FSR 0.5 dB  
fIN = 100 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
fIN = 50 MHz, VIN = FSR 0.5 dB  
fIN = 100 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
fIN = 50 MHz, VIN = FSR 0.5 dB  
fIN = 100 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
fIN = 50 MHz, VIN = FSR 0.5 dB  
fIN = 100 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
fIN = 50 MHz, VIN = FSR 0.5 dB  
fIN = 100 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
fIN = 50 MHz, VIN = FSR 0.5 dB  
fIN = 100 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
fIN = 50 MHz, VIN = FSR 0.5 dB  
fIN = 100 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
ENOB  
SINAD  
SNR  
Effective Number of Bits  
7.1  
7.1  
Bits (min)  
Bits (min)  
dB  
Signal-to-Noise Plus Distortion Ratio  
Signal-to-Noise Ratio  
47  
44.5  
44.5  
dB (min)  
dB (min)  
dB  
47  
48  
48  
45.3  
45.3  
dB (min)  
dB (min)  
dB  
47.5  
-55  
-55  
-55  
60  
60  
60  
65  
65  
65  
55  
THD  
Total Harmonic Distortion  
47.5  
47.5  
dB (max)  
dB (max)  
dB  
2nd Harm Second Harmonic Distortion  
3rd Harm Third Harmonic Distortion  
dB  
dB  
dB  
dB  
dB  
dB  
SFDR  
IMD  
Spurious-Free dynamic Range  
Intermodulation Distortion  
55  
47.5  
47.5  
dB (min)  
dB (min)  
55  
fIN1 = 121 MHz, VIN = FSR 7 dB  
fIN2 = 126 MHz, VIN = FSR 7 dB  
-50  
dB  
(VIN+) (VIN) > + Full Scale  
(VIN+) (VIN) < Full Scale  
255  
0
Out of Range Output Code  
(In addition to OR Output high)  
INTERLEAVE MODE (DES Pin 127=Float) - DYNAMIC CONVERTER CHARACTERISTICS  
FPBW  
(DES)  
Full Power Bandwidth  
Dual Edge Sampling Mode  
900  
MHz  
fIN = 100 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
fIN = 100 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
fIN = 100 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
fIN = 100 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
fIN = 100 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
fIN = 100 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
fIN = 248 MHz, VIN = FSR 0.5 dB  
7.4  
7.4  
7.0  
7.0  
Bits (min)  
Bits (min)  
dB (min)  
dB (min)  
dB (min)  
dB (min)  
dB (min)  
dB (min)  
dB  
ENOB  
Effective Number of Bits  
46.3  
46.3  
46.7  
46.7  
-58  
-58  
-60  
-60  
-64  
-64  
57  
43.9  
43.9  
44.1  
44.1  
-49  
SINAD  
SNR  
Signal to Noise Plus Distortion Ratio  
Signal to Noise Ratio  
THD  
Total Harmonic Distortion  
-49  
2nd Harm Second Harmonic Distortion  
3rd Harm Third Harmonic Distortion  
dB  
dB  
dB  
47  
47  
dB(min)  
dB dB (min(min)  
SFDR  
Spurious Free Dynamic Range  
57  
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Converter Electrical Characteristics (continued)  
The following specifications apply after calibration for VA = VDR = +1.9VDC, OutV = 1.9V, VIN FSR (a.c. coupled) = differential  
870mVP-P, CL = 10 pF, Differential, a.c. coupled Sinewave Input Clock, fCLK = 500 MHz at 0.5VP-P with 50% duty cycle, VBG  
Floating, Non-Extended Control Mode, SDR Mode, REXT = 3300±0.1%, Analog Signal Source Impedance = 100Ω  
Differential. Boldface limits apply for TA = TMIN to TMAX. All other limits TA = 25°C, unless otherwise noted. (1) (2)  
=
Typical  
Limits  
Units  
(Limits)  
Symbol  
ANALOG INPUT AND REFERENCE CHARACTERISTICS  
FSR pin 14 Low  
Parameter  
Conditions  
(3)  
(3)  
570  
730  
mVP-P (min)  
mVP-P (max)  
mVP-P (min)  
mVP-P (max)  
650  
Full Scale Analog Differential Input  
Range  
VIN  
790  
FSR pin 14 High  
870  
950  
V
CMO 50  
mV (min)  
mV (max)  
VCMI  
Analog Input Common Mode Voltage  
Analog Input Capacitance, Normal  
VCMO  
VCMO + 50  
Differential  
0.02  
1.6  
pF  
pF  
(5) (6)  
operation  
Each input pin to ground  
Differential  
CIN  
0.08  
2.2  
pF  
Analog Input Capacitance, DES Mode  
(5) (6)  
Each input pin to ground  
pF  
94  
(min)  
(max)  
RIN  
Differential Input Resistance  
100  
106  
ANALOG OUTPUT CHARACTERISTICS  
0.95  
1.45  
V (min)  
V (max)  
VCMO  
Common Mode Output Voltage  
1.26  
VA = 1.8V  
VA = 2.0V  
0.60  
0.66  
V
V
VCMO input threshold to set DC  
Coupling mode  
VCMO_LVL  
TC VCMO  
Common Mode Output Voltage  
Temperature Coefficient  
TA = 40°C to +85°C  
118  
ppm/°C  
pF  
CLOAD  
VCMO  
Maximum VCMO load Capacitance  
Bandgap Reference Output Voltage  
80  
1.20  
1.33  
V (min)  
V (max)  
VBG  
IBG = ±100 µA  
1.26  
28  
Bandgap Reference Voltage  
Temperature Coefficient  
TC VBG  
CLOAD VBG  
TA = 40°C to +85°C, IBG = ±100 µA  
ppm/°C  
pF  
Maximum Bandgap Reference Load  
Capacitance  
80  
TEMPERATURE DIODE CHARACTERISTICS  
192 µA vs. 12 µA,  
TJ = 25°C  
71.23  
85.54  
mV  
mV  
ΔVBE  
Temperature Diode Voltage  
192 µA vs. 12 µA,  
TJ = 85°C  
CHANNEL-TO-CHANNEL CHARACTERISTICS  
Offset Error Match  
1
1
LSB  
LSB  
Positive Full-Scale Error Match  
Negative Full-Scale Error Match  
Phase Matching (I, Q)  
Zero offset selected in Control Register  
Zero offset selected in Control Register  
FIN = 1.0 GHz  
1
LSB  
< 1  
Degree  
Crosstalk from I (Aggressor) to Q  
(Victim) Channel  
Aggressor = 867 MHz F.S.  
Victim = 100 MHz F.S.  
X-TALK  
71  
dB  
dB  
Crosstalk from Q (Aggressor) to I  
(Victim) Channel  
Aggressor = 867 MHz F.S.  
Victim = 100 MHz F.S.  
X-TALK  
-71  
(5) The analog and clock input capacitances are die capacitances only. Additional package capacitances of 0.65 pF differential and 0.95 pF  
each pin to ground are isolated from the die capacitances by lead and bond wire inductances.  
(6) This parameter is specified by design and is not tested in production.  
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Converter Electrical Characteristics (continued)  
The following specifications apply after calibration for VA = VDR = +1.9VDC, OutV = 1.9V, VIN FSR (a.c. coupled) = differential  
870mVP-P, CL = 10 pF, Differential, a.c. coupled Sinewave Input Clock, fCLK = 500 MHz at 0.5VP-P with 50% duty cycle, VBG  
Floating, Non-Extended Control Mode, SDR Mode, REXT = 3300±0.1%, Analog Signal Source Impedance = 100Ω  
Differential. Boldface limits apply for TA = TMIN to TMAX. All other limits TA = 25°C, unless otherwise noted. (1) (2)  
=
Typical  
Limits  
Units  
(Limits)  
Symbol  
Parameter  
Conditions  
(3)  
(3)  
CLOCK INPUT CHARACTERISTICS  
0.4  
2.0  
VP-P (min)  
VP-P (max)  
Sine Wave Clock  
0.6  
0.6  
VID  
Differential Clock Input Level  
Input Current  
0.4  
2.0  
VP-P (min)  
VP-P (max)  
Square Wave Clock  
II  
VIN = 0 or VIN = VA  
Differential  
±1  
0.02  
1.5  
µA  
pF  
pF  
(7) (8)  
CIN  
Input Capacitance  
Each input to ground  
DIGITAL CONTROL PIN CHARACTERISTICS  
(9)  
VIH  
VIL  
CIN  
Logic High Input Voltage  
Logic Low Input Voltage  
See  
0.85 x VA  
0.15 x VA  
V (min)  
V (max)  
pF  
(9)  
See  
(8) (10)  
Input Capacitance  
Each input to ground  
1.2  
DIGITAL OUTPUT CHARACTERISTICS  
400  
920  
280  
720  
mVP-P (min)  
mVP-P (max)  
mVP-P (min)  
mVP-P (max)  
Measured differentially, OutV = VA,  
VBG = Floating,  
710  
(11)  
VOD  
LVDS Differential Output Voltage  
Measured differentially, OutV = GND,  
510  
±1  
(11)  
VBG = Floating,  
Change in LVDS Output Swing  
Between Logic Levels  
Δ VO DIFF  
mV  
VOS  
VOS  
Output Offset Voltage, see Figure 1  
Output Offset Voltage, see Figure 1  
VBG = Floating  
800  
mV  
mV  
(11)  
VBG = VA  
1200  
Output Offset Voltage Change  
Between Logic Levels  
Δ VOS  
±1  
mV  
IOS  
Output Short Circuit Current  
Differential Output Impedance  
Cal_Run High level output  
Cal_Run Low level output  
Output+ & Output- connected to 0.8V  
4  
mA  
Ohms  
V
ZO  
100  
1.65  
0.15  
(9)  
VOH  
VOL  
IOH = -400uA  
1.5  
0.3  
(9)  
IOH = 400uA  
V
POWER SUPPLY CHARACTERISTICS  
PD = PDQ = Low  
PD = Low, PDQ = High  
PD = PDQ = High  
561  
340  
1.8  
665  
408  
mA (max)  
mA  
IA  
Analog Supply Current  
Output Driver Supply Current  
Power Consumption  
mA  
PD = PDQ = Low  
PD = Low, PDQ = High  
PD = PDQ = High  
200  
112  
0.012  
275  
157  
mA (max)  
mA (max)  
mA  
IDR  
PD = PDQ = Low  
PD = Low, PDQ = High  
PD = PDQ = High  
1.4  
0.8  
3.5  
1.78  
1.0  
W (max)  
W
mW  
PD  
Change in Full Scale Error with change  
in VA from 1.8V to 2.0V  
PSRR1  
PSRR2  
D.C. Power Supply Rejection Ratio  
A.C. Power Supply Rejection Ratio  
30  
51  
dB  
dB  
248 MHz, 50mVP-P riding on VA  
(7) The analog and clock input capacitances are die capacitances only. Additional package capacitances of 0.65 pF differential and 0.95 pF  
each pin to ground are isolated from the die capacitances by lead and bond wire inductances.  
(8) This parameter is specified by design and is not tested in production.  
(9) This parameter is specified by design and/or characterization and is not tested in production.  
(10) The digital control pin capacitances are die capacitances only. Additional package capacitance of 1.6 pF each pin to ground are isolated  
from the die capacitances by lead and bond wire inductances.  
(11) Tying VBG to the supply rail will increase the output offset voltage (VOS) by 400mv (typical), as shown in the VOS specification above.  
Tying VBG to the supply rail will also affect the differential LVDS output voltage (VOD), causing it to increase by 40mV (typical).  
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Converter Electrical Characteristics (continued)  
The following specifications apply after calibration for VA = VDR = +1.9VDC, OutV = 1.9V, VIN FSR (a.c. coupled) = differential  
870mVP-P, CL = 10 pF, Differential, a.c. coupled Sinewave Input Clock, fCLK = 500 MHz at 0.5VP-P with 50% duty cycle, VBG  
Floating, Non-Extended Control Mode, SDR Mode, REXT = 3300±0.1%, Analog Signal Source Impedance = 100Ω  
Differential. Boldface limits apply for TA = TMIN to TMAX. All other limits TA = 25°C, unless otherwise noted. (1) (2)  
=
Typical  
Limits  
Units  
(Limits)  
Symbol  
Parameter  
Conditions  
(3)  
(3)  
AC ELECTRICAL CHARACTERISTICS  
fCLK1  
fCLK2  
fCLK2  
Maximum Input Clock Frequency  
Minimum Input Clock Frequency  
Minimum Input Clock Frequency  
Normal Mode (non DES) or DES Mode  
Normal Mode (non DES)  
DES Mode  
500  
MHz (min)  
MHz  
200  
450  
MHz  
200 MHz Input clock frequency 500  
MHz (Normal Mode)(12)  
20  
80  
% (min)  
% (max)  
Input Clock Duty Cycle  
Input Clock Duty Cycle  
50  
50  
450 MHz Input clock frequency 500  
MHz (DES Mode)(12)  
20  
80  
% (min)  
% (max)  
(12)  
tCL  
Input Clock Low Time  
Input Clock High Time  
See  
500  
500  
400  
400  
ps (min)  
ps (min)  
(12)  
tCH  
See  
45  
55  
% (min)  
% (max)  
(12)  
DCLK Duty Cycle  
See  
50  
(12)  
tRS  
tRH  
Reset Setup Time  
Reset Hold Time  
See  
150  
250  
ps  
ps  
(12)  
See  
Synchronizing Edge to DCLK Output  
Delay  
fCLKIN = 500 MHz  
fCLKIN = 200 MHz  
3.53  
3.85  
tSD  
ns  
Clock Cycles  
(min)  
(13)  
tRPW  
tLHT  
tHLT  
Reset Pulse Width  
See  
4
Differential Low to High Transition  
Time  
10% to 90%, CL = 2.5 pF  
10% to 90%, CL = 2.5 pF  
250  
250  
ps  
ps  
Differential High to Low Transition  
Time  
50% of DCLK transition to 50% of Data  
transition, SDR Mode  
and DDR Mode, 0° DCLK  
tOSK  
DCLK to Data Output Skew  
±50  
ps (max)  
(12)  
(12)  
tSU  
tH  
tAD  
tAJ  
Data to DCLK Set-Up Time  
DCLK to Data Hold Time  
Sampling (Aperture) Delay  
Aperture Jitter  
DDR Mode, 90° DCLK  
2
ns  
ns  
(12)  
DDR Mode, 90° DCLK  
2
Input CLK+ Fall to Acquisition of Data  
1.3  
0.4  
ns  
ps rms  
Input Clock to Data Output Delay (in  
addition to Pipeline Delay)  
50% of Input Clock transition to 50% of  
Data transition  
tOD  
3.1  
ns  
DI Outputs  
13  
14  
DId Outputs  
Normal Mode  
DQ Outputs  
13  
Pipeline Delay (Latency)(13) (14)  
Clock Cycles  
DES Mode  
13.5  
14  
Normal Mode  
DQd Outputs  
DES Mode  
14.5  
Differential VIN step from ±1.2V to 0V  
to get accurate conversion  
Input Clock  
Cycle  
Over Range Recovery Time  
1
PD low to Rated Accuracy Conversion  
(Wake-Up Time)  
tWU  
500  
ns  
(12)  
fSCLK  
tSSU  
Serial Clock Frequency  
See  
100  
2.5  
MHz  
(12)  
Data to Serial Clock Setup Time  
See  
ns (min)  
(12) This parameter is specified by design and/or characterization and is not tested in production.  
(13) This parameter is specified by design and is not tested in production.  
(14) Each of the two converters of the ADC08D500 has two LVDS output buses, which each clock data out at one half the sample rate. The  
data at each bus is clocked out at one half the sample rate. The second bus (D0 through D7) has a pipeline latency that is one clock  
cycle less than the latency of the first bus (Dd0 through Dd7)  
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Converter Electrical Characteristics (continued)  
The following specifications apply after calibration for VA = VDR = +1.9VDC, OutV = 1.9V, VIN FSR (a.c. coupled) = differential  
870mVP-P, CL = 10 pF, Differential, a.c. coupled Sinewave Input Clock, fCLK = 500 MHz at 0.5VP-P with 50% duty cycle, VBG  
Floating, Non-Extended Control Mode, SDR Mode, REXT = 3300±0.1%, Analog Signal Source Impedance = 100Ω  
Differential. Boldface limits apply for TA = TMIN to TMAX. All other limits TA = 25°C, unless otherwise noted. (1) (2)  
=
Typical  
Limits  
Units  
(Limits)  
Symbol  
tSH  
Parameter  
Conditions  
(3)  
(3)  
(12)  
Data to Serial Clock Hold Time  
Serial Clock Low Time  
See  
1
ns (min)  
ns (min)  
ns (min)  
4
4
Serial Clock High Time  
Calibration Cycle Time  
tCAL  
1.4 x 105  
Clock Cycles  
Clock Cycles  
(min)  
(13)  
(13)  
tCAL_L  
CAL Pin Low Time  
CAL Pin High Time  
See Figure 9  
See Figure 9  
80  
80  
Clock Cycles  
(min)  
tCAL_H  
tCalDly  
tCalDly  
Calibration delay determined by pin  
127  
Clock Cycles  
(min)  
(15)  
(15)  
See Self-Calibration, Figure 9,  
See Self-Calibration, Figure 9,  
225  
231  
Calibration delay determined by pin  
127  
Clock Cycles  
(max)  
(15) Tying VBG to the supply rail will increase the output offset voltage (VOS) by 400mv (typical), as shown in the VOS specification above.  
Tying VBG to the supply rail will also affect the differential LVDS output voltage (VOD), causing it to increase by 40mV (typical).  
Specification Definitions  
APERTURE (SAMPLING) DELAY is that time required after the fall of the clock input for the sampling switch to  
open. The Sample/Hold circuit effectively stops capturing the input signal and goes into the “hold” mode the  
aperture delay time (tAD) after the clock goes low.  
APERTURE JITTER (tAJ) is the variation in aperture delay from sample to sample. Aperture jitter shows up as  
input noise.  
Bit Error Rate (B.E.R.) is the probability of error and is defined as the probable number of errors per unit of time  
divided by the number of bits seen in that amount of time. A B.E.R. of 10-18 corresponds to a statistical error in  
one bit about every four (4) years.  
CLOCK DUTY CYCLE is the ratio of the time that the clock wave form is at a logic high to the total time of one  
clock period.  
DIFFERENTIAL NON-LINEARITY (DNL) is the measure of the maximum deviation from the ideal step size of 1  
LSB. Measured at 500 MSPS with a ramp input.  
EFFECTIVE NUMBER OF BITS (ENOB, or EFFECTIVE BITS) is another method of specifying Signal-to-Noise  
and Distortion Ratio, or SINAD. ENOB is defined as (SINAD 1.76) / 6.02 and says that the converter is  
equivalent to a perfect ADC of this (ENOB) number of bits.  
FULL POWER BANDWIDTH (FPBW) is a measure of the frequency at which the reconstructed output  
fundamental drops 3 dB below its low frequency value for a full scale input.  
GAIN ERROR is the deviation from the ideal slope of the transfer function. It can be calculated from Offset and  
Full-Scale Errors:  
Pos. Gain Error = Offset Error Pos. Full-Scale Error  
Neg. Gain Error = (Offset Error Neg. Full-Scale Error)  
Gain Error = Neg. Full-Scale Error Pos. Full-Scale Error  
= Pos. Gain Error + Neg. Gain Error  
INTEGRAL NON-LINEARITY (INL) is a measure of the deviation of each individual code from a straight line  
through the input to output transfer function. The deviation of any given code from this straight line is measured  
from the center of that code value. The best fit method is used.  
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INTERMODULATION DISTORTION (IMD) is the creation of additional spectral components as a result of two  
sinusoidal frequencies being applied to the ADC input at the same time. It is defined as the ratio of the power in  
the second and third order intermodulation products to the power in one of the original frequencies. IMD is  
usually expressed in dBFS.  
LSB (LEAST SIGNIFICANT BIT) is the bit that has the smallest value or weight of all bits. This value is  
VFS / 2n  
where VFS is the differential full-scale amplitude of 650 mV or 870 mV as set by the FSR input and "n" is the  
ADC resolution in bits, which is 8 for the ADC08D500.  
LVDS DIFFERENTIAL OUTPUT VOLTAGE (VOD) is the absolute value of the difference between the VD+ & VD-  
outputs; each measured with respect to Ground.  
VD+  
VD-  
VOD  
VD+  
VOS  
VD-  
GND  
VOD = | VD+ - VD- |  
Figure 1.  
LVDS OUTPUT OFFSET VOLTAGE (VOS) is the midpoint between the D+ and D- pins output voltage; i.e.,  
[(VD+) +( VD-)]/2.  
MISSING CODES are those output codes that are skipped and will never appear at the ADC outputs. These  
codes cannot be reached with any input value.  
MSB (MOST SIGNIFICANT BIT) is the bit that has the largest value or weight. Its value is one half of full scale.  
NEGATIVE FULL-SCALE ERROR (NFSE) is a measure of how far the last code transition is from the ideal 1/2  
LSB above a differential 870 mV with the FSR pin high, or 1/2 LSB above a differential 650 mV with the FSR  
pin low. For the ADC08D500 the reference voltage is assumed to be ideal, so this error is a combination of full-  
scale error and reference voltage error.  
OFFSET ERROR (VOFF) is a measure of how far the mid-scale point is from the ideal zero voltage differential  
input.  
Offset Error = Actual Input causing average of 8k samples to result in an average code of 127.5.  
OUTPUT DELAY (tOD) is the time delay after the falling edge of DCLK before the data update is present at the  
output pins.  
OVER-RANGE RECOVERY TIME is the time required after the differential input voltages goes from ±1.2V to 0V  
for the converter to recover and make a conversion with its rated accuracy.  
PIPELINE DELAY (LATENCY) is the number of clock cycles between initiation of conversion and when that data  
is presented to the output driver stage. New data is available at every clock cycle, but the data lags the  
conversion by the Pipeline Delay plus the tOD  
.
POSITIVE FULL-SCALE ERROR (PFSE) is a measure of how far the last code transition is from the ideal 1-1/2  
LSB below a differential +870 mV with the FSR pin high, or 1-1/2 LSB below a differential +650 mV with the FSR  
pin low. For the ADC08D500 the reference voltage is assumed to be ideal, so this error is a combination of full-  
scale error and reference voltage error.  
POWER SUPPLY REJECTION RATIO (PSRR) can be one of two specifications. PSRR1 (DC PSRR) is the ratio  
of the change in full-scale error that results from a power supply voltage change from 1.8V to 2.0V. PSRR2 (AC  
PSRR) is a measure of how well an a.c. signal riding upon the power supply is rejected from the output and is  
measured with a 248 MHz, 50 mVP-P signal riding upon the power supply. It is the ratio of the output amplitude of  
that signal at the output to its amplitude on the power supply pin. PSRR is expressed in dB.  
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SIGNAL TO NOISE RATIO (SNR) is the ratio, expressed in dB, of the rms value of the input signal at the output  
to the rms value of the sum of all other spectral components below one-half the sampling frequency, not  
including harmonics or d.c.  
SIGNAL TO NOISE PLUS DISTORTION (S/(N+D) or SINAD) is the ratio, expressed in dB, of the rms value of  
the input signal at the output to the rms value of all of the other spectral components below half the clock  
frequency, including harmonics but excluding d.c.  
SPURIOUS-FREE DYNAMIC RANGE (SFDR) is the difference, expressed in dB, between the rms values of the  
input signal at the output and the peak spurious signal, where a spurious signal is any signal present in the  
output spectrum that is not present at the input, excluding d.c.  
TOTAL HARMONIC DISTORTION (THD) is the ratio expressed in dB, of the rms total of the first nine harmonic  
levels at the output to the level of the fundamental at the output. THD is calculated as  
2
2
f10  
A
+ . . . + A  
f2  
THD = 20 x log  
2
A
f1  
where Af1 is the RMS power of the fundamental (output) frequency and Af2 through Af10 are the RMS power of  
the first 9 harmonic frequencies in the output spectrum.  
– Second Harmonic Distortion (2nd Harm) is the difference, expressed in dB, between the RMS power in the  
input frequency seen at the output and the power in its 2nd harmonic level at the output.  
– Third Harmonic Distortion (3rd Harm) is the difference expressed in dB between the RMS power in the input  
frequency seen at the output and the power in its 3rd harmonic level at the output.  
Transfer Characteristic  
IDEAL POSITIVE  
FULL-SCALE  
TRANSITION  
Output  
Code  
ACTUAL  
POSITIVE  
FULL-SCALE  
TRANSITION  
1111 1110 (254)  
1111 1111 (255)  
1111 1101 (253)  
POSITIVE  
FULL-SCALE  
ERROR  
MID-SCALE  
TRANSITION  
1000 0000 (128)  
0111 1111 (127)  
OFFSET  
ERROR  
IDEAL NEGATIVE  
FULL-SCALE TRANSITION  
ACTUAL NEGATIVE  
FULL-SCALE TRANSITION  
NEGATIVE  
FULL-SCALE  
ERROR  
0000 0010 (2)  
0000 0001 (1)  
0000 0000 (0)  
(VIN+) < (VIN-)  
(VIN+) > (VIN-)  
0.0V  
-325 mV /  
-435 mV  
+325 mV /  
+435 mV  
Differential Analog Input Voltage (VIN+) - (VIN-)  
Figure 2. Input / Output Transfer Characteristic  
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Timing Diagrams  
Sample N  
D
Sample N-1  
Dd  
V
IN  
Sample N+1  
t
AD  
CLK, CLK  
t
OD  
Sample N-18 and  
Sample N-17  
DId, DI  
DQd, DQ  
Sample N-16 and Sample N-15  
Sample N-14 and Sample N-13  
t
OSK  
DCLK+, DCLK-  
(OutEdge = 0)  
DCLK+, DCLK-  
(OutEdge = 1)  
Figure 3. ADC08D500 Timing — SDR Clocking  
Sample N  
D
Sample N-1  
Dd  
V
IN  
Sample N+1  
t
AD  
CLK, CLK  
t
OD  
DId, DI  
DQd, DQ  
Sample N-18 and  
Sample N-17  
Sample N-16 and Sample N-15  
Sample N-14 and Sample N-13  
t
OSK  
DCLK+, DCLK-  
(0°Phase)  
t
t
H
SU  
DCLK+, DCLK-  
(90°Phase)  
Figure 4. ADC08D500 Timing — DDR Clocking  
Single Register Access  
SCS  
1
12 13  
16 17  
32  
SCLK  
SDATA  
Register Address  
Fixed Header Pattern  
Register Write Data  
t
MSB  
LSB  
SH  
t
SSU  
Figure 5. Serial Interface Timing  
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Synchronizing Edge  
CLK  
t
RH  
t
RS  
t
AD  
DCLK_RST  
DCLK+  
t
RPW  
Figure 6. Clock Reset Timing in DDR Mode  
Synchronizing Edge  
CLK  
t
RH  
t
RS  
t
SD  
DCLK_RST  
t
RPW  
DCLK+  
OUTEDGE  
Figure 7. Clock Reset Timing in SDR Mode with OUTEDGE Low  
Synchronizing Edge  
CLK  
t
RH  
t
RS  
t
SD  
DCLK_RST  
t
RPW  
DCLK+  
OUTEDGE  
Figure 8. Clock Reset Timing in SDR Mode with OUTEDGE High  
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t
CAL  
t
CAL  
CalRun  
t
t
CalDly  
CAL_H  
Calibration Delay  
determined by  
CalDly Pin (127)  
CAL  
t
CAL_L  
POWER  
SUPPLY  
Figure 9. Self Calibration and On-Command Calibration Timing  
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Typical Performance Characteristics  
VA=VDR=1.9V, FCLK=500MHz, TA=25°C unless otherwise stated.  
INL  
vs.  
CODE  
INL  
vs.  
TEMPERATURE  
Figure 10.  
Figure 11.  
DNL  
vs.  
CODE  
DNL  
vs.  
TEMPERATURE  
Figure 12.  
Figure 13.  
ENOB  
vs.  
TEMPERATURE  
ENOB  
vs.  
SUPPLY VOLTAGE  
Figure 14.  
Figure 15.  
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Typical Performance Characteristics (continued)  
VA=VDR=1.9V, FCLK=500MHz, TA=25°C unless otherwise stated.  
ENOB  
SNR  
vs.  
TEMPERATURE  
vs.  
INPUT FREQUENCY  
Figure 16.  
Figure 17.  
SNR  
vs.  
SNR  
vs.  
SUPPLY VOLTAGE  
INPUT FREQUENCY  
Figure 18.  
Figure 19.  
THD  
vs.  
TEMPERATURE  
THD  
vs.  
SUPPLY VOLTAGE  
Figure 20.  
Figure 21.  
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Typical Performance Characteristics (continued)  
VA=VDR=1.9V, FCLK=500MHz, TA=25°C unless otherwise stated.  
THD  
SFDR  
vs.  
TEMPERATURE  
vs.  
INPUT FREQUENCY  
Figure 22.  
Figure 23.  
SFDR  
vs.  
SUPPLY VOLTAGE  
SFDR  
vs.  
INPUT FREQUENCY  
Figure 24.  
Figure 25.  
Spectral Response at FIN = 98 MHz  
Spectral Response at FIN = 248 MHz  
Figure 26.  
Figure 27.  
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Typical Performance Characteristics (continued)  
VA=VDR=1.9V, FCLK=500MHz, TA=25°C unless otherwise stated.  
CROSSTALK  
vs.  
SOURCE FREQUENCY  
FULL POWER BANDWIDTH  
Figure 28.  
Figure 29.  
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FUNCTIONAL DESCRIPTION  
The ADC08D500 is a versatile A/D Converter with an innovative architecture permitting very high speed  
operation. The controls available ease the application of the device to circuit solutions. Optimum performance  
requires adherence to the provisions discussed here and in the Applications Information Section.  
While it is generally poor practice to allow an active pin to float, pins 4, 14 and 127 of the ADC08D500 are  
designed to be left floating without jeopardy. In all discussions throughout this data sheet, whenever a function is  
called by allowing a pin to float, connecting that pin to a potential of one half the VA supply voltage will have the  
same effect as allowing it to float.  
OVERVIEW  
The ADC08D500 uses a calibrated folding and interpolating architecture that achieves over 7.5 effective bits. The  
use of folding amplifiers greatly reduces the number of comparators and power consumption. Interpolation  
reduces the number of front-end amplifiers required, minimizing the load on the input signal and further reducing  
power requirements. In addition to other things, on-chip calibration reduces the INL bow often seen with folding  
architectures. The result is an extremely fast, high performance, low power converter.  
The analog input signal that is within the converter's input voltage range is digitized to eight bits at speeds of 200  
MSPS to 500 MSPS, typical. Differential input voltages below negative full-scale will cause the output word to  
consist of all zeroes. Differential input voltages above positive full-scale will cause the output word to consist of  
all ones. Either of these conditions at either the "I" or "Q" input will cause the OR (Out of Range) output to be  
activated. This single OR output indicates when the output code from one or both of the channels is below  
negative full scale or above positive full scale.  
Each of the two converters has a 1:2 demultiplexer that feeds two LVDS output buses. The data on these buses  
provide an output word rate on each bus at half the ADC sampling rate and must be interleaved by the user to  
provide output words at the full conversion rate.  
The output levels may be selected to be normal or reduced. Using reduced levels saves power but could result in  
erroneous data capture of some or all of the bits, especially at higher sample rates and in marginally designed  
systems.  
Self-Calibration  
A self-calibration is performed upon power-up and can also be invoked by the user upon command. Calibration  
trims the 100analog input differential termination resistor and minimizes full-scale error, offset error, DNL and  
INL, resulting in maximizing SNR, THD, SINAD (SNDR) and ENOB. Internal bias currents are also set with the  
calibration process. All of this is true whether the calibration is performed upon power up or is performed upon  
command. Running the self calibration is an important part of this chip's functionality and is required in order to  
obtain adequate performance. In addition to the requirement to be run at power-up, self calibration must be re-  
run whenever the sense of the FSR pin is changed. For best performance, we recommend that self calibration be  
run 20 seconds or more after application of power and whenever the operating temperature changes  
significantly, according to the particular system design requirements. See On-Command Calibration for more  
information. Calibration can not be initiated or run while the device is in the power-down mode. See Power Down  
for information on the interaction between Power Down and Calibration.  
During the calibration process, the input termination resistor is trimmed to a value that is equal to REXT / 33. This  
external resistor is located between pin 32 and ground. REXT must be 3300 ±0.1%. With this value, the input  
termination resistor is trimmed to be 100 . Because REXT is also used to set the proper current for the Track  
and Hold amplifier, for the preamplifiers and for the comparators, other values of REXT should not be used. In  
normal operation, calibration is performed just after application of power and whenever a valid calibration  
command is given, which is holding the CAL pin low for at least 80 clock cycles, then hold it high for at least  
another 80 clock cycles. The time taken by the calibration procedure is specified in the A.C. Characteristics  
Table. Holding the CAL pin high upon power up will prevent the calibration process from running until the CAL  
pin experiences the above-mentioned 80 clock cycles low followed by 80 clock cycles high.  
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CalDly (pin 127) is used to select one of two delay times after the application of power to the start of calibration.  
This calibration delay is 225 clock cycles (about 67.2 ms at 500 MSPS) with CalDly low, or 231 clock cycles (about  
4.3 seconds at 500 MSPS) with CalDly high. These delay values allow the power supply to come up and stabilize  
before calibration takes place. If the PD pin is high upon power-up, the calibration delay counter will be disabled  
until the PD pin is brought low. Therefore, holding the PD pin high during power up will further delay the start of  
the power-up calibration cycle. The best setting of the CalDly pin depends upon the power-on settling time of the  
power supply.  
The CalRun output is high whenever the calibration procedure is running. This is true whether the calibration is  
done at power-up or on-command.  
Acquiring the Input  
Data is acquired at the falling edge of CLK+ (pin 18) and the digital equivalent of that data is available at the  
digital outputs 13 clock cycles later for the DI and DQ output buses and 14 clock cycles later for the DId and DQd  
output buses. There is an additional internal delay called tOD before the data is available at the outputs. See the  
Timing Diagram. The ADC08D500 will convert as long as the clock signal is present. The fully differential  
comparator design and the innovative design of the sample-and-hold amplifier, together with self calibration,  
enables a very flat SINAD/ENOB response beyond 500 MHz. The ADC08D500 output data signaling is LVDS  
and the output format is offset binary.  
Control Modes  
Much of the user control can be accomplished with several control pins that are provided. Examples include  
initiation of the calibration cycle, power down mode and full scale range setting. However, the ADC08D500 also  
provides an Extended Control mode whereby a serial interface is used to access register-based control of  
several advanced features. The Extended Control mode is not intended to be enabled and disabled dynamically.  
Rather, the user is expected to employ either the normal control mode or the Extended Control mode at all times.  
When the device is in the Extended Control mode, pin-based control of several features is replaced with register-  
based control and those pin-based controls are disabled. These pins are OutV (pin 3), OutEdge/DDR (pin 4),  
FSR (pin 14) and CalDly/DES (pin 127). See NORMAL/EXTENDED CONTROL for details on the Extended  
Control mode.  
The Analog Inputs  
The ADC08D500 must be driven with a differential input signal. Operation with a single-ended signal is not  
recommended. It is important that the inputs either be a.c. coupled to the inputs with the VCMO pin grounded or  
d.c. coupled with the VCMO pin not grounded and an input common mode voltage equal to the VCMO output.  
Two full-scale range settings are provided with pin 14 (FSR). A high on pin 14 causes an input full-scale range  
setting of 870 mVP-P, while grounding pin 14 causes an input full-scale range setting of 650 mVP-P. The full-scale  
range setting operates equally on both ADCs.  
In the Extended Control mode, the full-scale input range can be set to values between 560 mVP-P and 840 mVP-P  
through a serial interface. See THE ANALOG INPUT.  
Clocking  
The ADC08D500 must be driven with an a.c. coupled, differential clock signal. THE CLOCK INPUTS describes  
the use of the clock input pins. A differential LVDS output clock is available for use in latching the ADC output  
data into whatever receives that data.  
The ADC08D500 offers options for input and output clocking. These options include a choice of Dual Edge  
Sampling (DES) or interleaved mode where the ADC08D500 performs as a single device converting at twice the  
input clock rate and a choice of which DCLK edge the output data transitions on and choice of Single Data Rate  
(SDR) or Double Data Rate (DDR) outputs.  
The ADC08D500 also has the option to use a duty cycle corrected clock receiver as part of the input clock  
circuit. This feature is enabled by default and provides improved ADC clocking, especially in the Dual-Edge  
Sampling mode (DES). This circuitry allows the ADC to be clocked with a signal source having a duty cycle ratio  
of 80 / 20 % (worst case) for both the normal and the Dual Edge Sampling modes.  
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Dual-Edge Sampling  
The DES mode allows one of the ADC08D500's inputs (I or Q Channel) to be sampled by both ADCs. One ADC  
samples the input on the positive edge of the input clock and the other ADC samples the same input on the other  
edge of the input clock. A single input is thus sampled twice per clock cycle, resulting in an overall sample rate of  
twice the input clock frequency, or 1 GSPS with a 500 MHz clock.  
In this mode the outputs are interleaved such that the data is effectively demultiplexed 1:4. Since the sample rate  
is doubled, each of the 4 output buses have a 250 MSPS output rate with a 500 MHz input clock. All data is  
available in parallel. The four bytes of parallel data that is output with each clock is in the following sampling  
order, from the earliest to the latest: DQd, DId, DQ, DI. Table 1 indicates what the outputs represent for the  
various sampling possibilities.  
In the non-extended mode of operation only the "I" input can be sampled in the DES mode. In the extended  
mode of operation the user can select which input is sampled.  
The ADC08D500 also includes an automatic clock phase background calibration feature which can be used in  
DES mode to automatically and continuously adjust the clock phase of the I and Q channel. This feature  
removes the need to adjust the clock phase setting manually and provides optimal Dual-Edge Sampling ENOB  
performance.  
NOTE  
The background calibration feature in DES mode does not replace the requirement for On-  
Command Calibration which should be run before entering DES mode, or if a large swing  
in ambient temperature is experienced by the device.  
Table 1. Input Channel Samples Produced at Data Outputs  
Data Outputs  
Dual-Edge Sampling Mode  
(Always sourced with  
respect to fall of DCLK)  
Normal Sampling Mode  
(1)  
I-Channel Selected  
Q-Channel Selected  
"I" Input Sampled with Fall of  
CLK 13 cycles earlier.  
"I" Input Sampled with Fall of  
CLK 13 cycles earlier.  
"Q" Input Sampled with Fall of  
CLK 13 cycles earlier.  
DI  
"I" Input Sampled with Fall of  
CLK 14 cycles earlier.  
"I" Input Sampled with Fall of  
CLK 14 cycles earlier.  
"Q" Input Sampled with Fall of  
CLK 14 cycles earlier.  
DId  
DQ  
"Q" Input Sampled with Fall of  
CLK 13 cycles earlier.  
"I" Input Sampled with Rise of  
CLK 13.5 cycles earlier.  
"Q" Input Sampled with Rise of  
CLK 13.5 cycles earlier.  
"Q" Input Sampled with Fall of  
CLK 14 cycles after being  
sampled.  
"I" Input Sampled with Rise of  
CLK 14.5 cycles earlier.  
"Q" Input Sampled with Rise of  
CLK 14.5 cycles earlier.  
DQd  
(1) In DES + normal mode, only the I Channel is sampled. In DES + extended control mode, I or Q channel can be sampled.  
OutEdge Setting  
To help ease data capture in the SDR mode, the output data may be caused to transition on either the positive or  
the negative edge of the output data clock (DCLK). This is chosen with the OutEdge input (pin 4). A high on the  
OutEdge input causes the output data to transition on the rising edge of DCLK, while grounding this input causes  
the output to transition on the falling edge of DCLK. See Output Edge Synchronization.  
Double Data Rate  
A choice of single data rate (SDR) or double data rate (DDR) output is offered. With single data rate the clock  
frequency is the same as the data rate of the two output buses. With double data rate the clock frequency is half  
the data rate and data is sent to the outputs on both DCLK edges. DDR clocking is enabled in non-Extended  
Control mode by allowing pin 4 to float.  
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The LVDS Outputs  
The data outputs, the Out Of Range (OR) and DCLK, are LVDS. Output current sources provide 3 mA of output  
current to a differential 100 Ohm load when the OutV input (pin 14) is high or 2.2 mA when the OutV input is low.  
For short LVDS lines and low noise systems, satisfactory performance may be realized with the OutV input low,  
which results in lower power consumption. If the LVDS lines are long and/or the system in which the  
ADC08D500 is used is noisy, it may be necessary to tie the OutV pin high. The LVDS data output have a typical  
common mode voltage of 800mV when the VBG pin is unconnected and floating. This common mode voltage can  
be increased to 1.2V by tying the VBG pin to VA if a higher common mode is required.  
NOTE  
Tying the VBG pin to VA will also increase the differential LVDS output voltage by up to  
40mV.  
Power Down  
The ADC08D500 is in the active state when the Power Down pin (PD) is low. When the PD pin is high, the  
device is in the power down mode, where the output pins hold the last conversion before the PD pin went high  
and the device power consumption is reduced to a minimal level. A high on the PDQ pin will power down the "Q"  
channel and leave the "I" channel active. There is no provision to power down the "I" channel independently of  
the "Q" channel. Upon return to normal operation, the pipeline will contain meaningless information.  
If the PD input is brought high while a calibration is running, the device will not go into power down until the  
calibration sequence is complete. However, if power is applied and PD is already high, the device will not begin  
the calibration sequence until the PD input goes low. If a manual calibration is requested while the device is  
powered down, the calibration will not begin at all. That is, the manual calibration input is completely ignored in  
the power down state. Calibration will function with the "Q" channel powered down, but that channel will not be  
calibrated if PDQ is high. If the "Q" channel is subsequently to be used, it is necessary to perform a calibration  
after PDQ is brought low.  
NORMAL/EXTENDED CONTROL  
The ADC08D500 may be operated in one of two modes. In the simpler "normal" control mode, the user affects  
available configuration and control of the device through several control pins. The "extended control mode"  
provides additional configuration and control options through a serial interface and a set of 8 registers. The two  
control modes are selected with pin 14 (FSR/ECE: Extended Control Enable). The choice of control modes is  
required to be a fixed selection and is not intended to be switched dynamically while the device is operational.  
Table 2 shows how several of the device features are affected by the control mode chosen.  
Table 2. Features and Modes  
Feature  
SDR or DDR Clocking  
Normal Control Mode  
Extended Control Mode  
Selected with DE bit in the Configuration  
Register (1h).  
Selected with pin 4  
Selected with DCP bit in the Configuration  
Register (1h). See REGISTER DESCRIPTION  
DDR Clock Phase  
Not Selectable (0° Phase Only)  
Selected with pin 4  
SDR Data transitions with rising or falling  
DCLK edge  
Selected with the OE bit in the Configuration  
Register (1h).  
Selected with the OV bit in the Configuration  
Register (1h).  
LVDS output level  
Selected with pin 3  
Power-On Calibration Delay  
Delay Selected with pin 127  
Short delay only.  
Up to 512 step adjustments over a nominal  
range of 560 mV to 840 mV. Separate range  
selected for I- and Q-Channels. Selected using  
registers 3h and Bh.  
Options (650 mVP-P or 870 mVP-P) selected  
with pin 14. Selected range applies to both  
channels.  
Full-Scale Range  
Separate ±45 mV adjustments in 512 steps for  
each channel using registers 2h and Ah.  
Input Offset Adjust  
Not possible  
Dual Edge Sampling Selection  
Enabled with pin 127  
Only I-Channel Input can be used  
Enabled through DES Enable Register (1h).  
Dual Edge Sampling Input Channel  
Selection  
Either I- or Q-Channel input may be sampled  
by both ADCs  
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Table 2. Features and Modes (continued)  
Automatic Clock Phase control can be selected  
by setting bit 14 in the DES Enable register  
(Dh). The clock phase can also be adjusted  
manually through the Coarse & Fine registers  
Eh and Fh.  
DES Sampling Clock Adjustment  
The Clock Phase is adjusted automatically  
The default state of the Extended Control Mode is set upon power-on reset (internally performed by the device)  
and is shown in Table 3.  
Table 3. Extended Control Mode Operation  
(Pin 14 Floating)  
Feature  
Extended Control Mode Default State  
DDR Clocking  
SDR or DDR Clocking  
DDR Clock Phase  
Data changes with DCLK edge (0° phase)  
Normal amplitude  
LVDS Output Amplitude  
(710 mVP-P  
)
Calibration Delay  
Full-Scale Range  
Short Delay  
700 mV nominal for both channels  
No adjustment for either channel  
Not enabled  
Input Offset Adjust  
Dual Edge Sampling (DES)  
THE SERIAL INTERFACE  
NOTE  
During the initial write using the serial interface, all 8 user registers must be written with  
desired or default values. In addition, the first write to the DES Enable register (Dh) must  
load the default value (0x3FFFh). Once all registers have been written once, other desired  
settings, including enabling DES can be loaded.  
The 3-pin serial interface is enabled only when the device is in the Extended Control  
mode. The pins of this interface are Serial Clock (SCLK), Serial Data (SDATA) and Serial  
Interface Chip Select (SCS) Eight write only registers are accessible through this serial  
interface.  
SCS: This signal should be asserted low while accessing a register through the serial interface. Setup and hold  
times with respect to the SCLK must be observed.  
SCLK: Serial data input is accepted with the rising edge of this signal. There is no minimum frequency  
requirement for SCLK.  
SDATA: Each register access requires a specific 32-bit pattern at this input. This pattern consists of a header,  
register address and register value. The data is shifted in MSB first. Setup and hold times with respect to the  
SCLK must be observed. See the Timing Diagram.  
Each Register access consists of 32 bits, as shown in Figure 5 of the Timing Diagrams. The fixed header pattern  
is 0000 0000 0001 (eleven zeros followed by a 1). The loading sequence is such that a 0b is loaded first. These  
12 bits form the header. The next 4 bits are the address of the register that is to be written to and the last 16 bits  
are the data written to the addressed register. The addresses of the various registers are indicated in Table 4.  
Refer to the REGISTER DESCRIPTION for information on the data to be written to the registers.  
Subsequent register accesses may be performed immediately, starting with the 33rd SCLK. This means that the  
SCS input does not have to be de-asserted and asserted again between register addresses. It is possible,  
although not recommended, to keep the SCS input permanently enabled (at a logic low) when using extended  
control.  
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NOTE  
The Serial Interface should not be used when calibrating the ADC. Doing so will impair the  
performance of the device until it is re-calibrated correctly. Programming the serial  
registers will also reduce dynamic performance of the ADC for the duration of the register  
access time.  
Table 4. Register Addresses  
4-Bit Address  
Loading Sequence:  
A3 loaded after Fixed Header Pattern, A0 loaded last  
A3  
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
A2  
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
A1  
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
A0  
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Hex  
0h  
1h  
2h  
3h  
4h  
5h  
6h  
7h  
8h  
9h  
Ah  
Bh  
Ch  
Dh  
Eh  
Fh  
Register Addressed  
Reserved  
Configuration  
"I" Ch Offset  
"I" Ch Full-Scale Voltage Adjust  
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
Reserved  
"Q" Ch Offset  
"Q" Ch Full-Scale Voltage Adjust  
Reserved  
DES Enable  
DES Coarse Adjust  
DES Fine Adjust  
REGISTER DESCRIPTION  
Eight write-only registers provide several control and configuration options in the Extended Control Mode. These  
registers have no effect when the device is in the Normal Control Mode. Each register description below also  
shows the Power-On Reset (POR) state of each control bit.  
Table 5. Configuration Register  
Addr: 1h (0001b)  
W only (0xB2FF)  
D15  
1
D14  
0
D13  
1
D12  
D11  
D10  
nDE  
D9  
D8  
DCS  
DCP  
OV  
OE  
D7  
1
D6  
1
D5  
1
D4  
1
D3  
1
D2  
1
D1  
1
D0  
1
IMPORTANT: The Configuration Register should not be written if the DES Enable bit = 1. The DES Enable bit should first be changed to 0,  
then the Configuration Register can be written. Failure to follow this procedure can cause the internal DES clock generation circuitry to stop.  
Bit 15  
Bit 14  
Bit 13  
Bit 12  
Must be set to 1b  
Must be set to 0b  
Must be set to 1b  
DCS: Duty Cycle Stabilizer. When this bit is set to 1b, a duty cycle stabilization circuit is applied to the clock  
input. When this bit is set to 0b the stabilization circuit is disabled.  
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Bit 11  
DCP: DDR Clock Phase. This bit only has an effect in the DDR mode. When this bit is set to 0b, the DCLK  
edges are time-aligned with the data bus edges ("0° Phase"). When this bit is set to 1b, the DCLK edges are  
placed in the middle of the data bit-cells ("90° Phase"), using the one-half speed DCLK shown in Figure 4 as  
the phase reference.  
POR State: 0b  
Bit 10  
nDE: DDR Enable. When this bit is set to 0b, data bus clocking follows the DDR (Dual Data Rate) mode  
whereby a data word is output with each rising and falling edge of DCLK. When this bit is set to a 1b, data bus  
clocking follows the SDR (single data rate) mode whereby each data word is output with either the rising or  
falling edge of DCLK, as determined by the OutEdge bit.  
POR State: 0b  
Bit 9  
Bit 8  
OV: Output Voltage. This bit determines the LVDS outputs' voltage amplitude and has the same function as the  
OutV pin that is used in the normal control mode. When this bit is set to 1b, the standard output amplitude of  
710 mVP-P is used. When this bit is set to 0b, the reduced output amplitude of 510 mVP-P is used.  
POR State: 1b  
OE: Output Edge. This bit selects the DCLK edge with which the data words transition in the SDR mode and  
has the same effect as the OutEdge pin in the normal control mode. When this bit is 1b, the data outputs  
change with the rising edge of DCLK+. When this bit is 0b, the data output change with the falling edge of  
DCLK+.  
POR State: 0b  
Bits 7:0  
Must be set to 1b.  
Table 6. I-Channel Offset  
Addr: 2h (0010b)  
W only (0x007F)  
D15  
D14  
D13  
D12  
D11  
D10  
D9  
D8  
(MSB)  
Offset Value  
(LSB)  
D7  
D6  
1
D5  
1
D4  
1
D3  
1
D2  
1
D1  
1
D0  
1
Sign  
Bits 15:8  
Offset Value. The input offset of the I-Channel ADC is adjusted linearly and monotonically by the value in this  
field. 00h provides a nominal zero offset, while FFh provides a nominal 45 mV of offset. Thus, each code step  
provides 0.176 mV of offset.  
POR State: 0000 0000b  
Bit 7  
Sign bit. 0b gives positive offset, 1b gives negative offset.  
POR State: 0b  
Bit 6:0  
Must be set to 1b  
Table 7. I-Channel Full-Scale Voltage Adjust  
Addr: 3h (0011b)  
W only (0x807F)  
D15  
D14  
D13  
D12  
D11  
D10  
D9  
D8  
(MSB)  
Adjust Value  
D7  
D6  
1
D5  
1
D4  
1
D3  
1
D2  
1
D1  
1
D0  
1
(LSB)  
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Bit 15:7  
Full Scale Voltage Adjust Value. The input full-scale voltage of the I-Channel ADC is adjusted linearly and  
monotonically from the nominal 700 mVP-P differential by the value in this field.  
0000 0000 0  
1000 0000 0  
1111 1111 1  
560mVP-P  
700mVP-P  
840mVP-P  
For best performance, it is recommended that the value in this field be limited to the range of 0110 0000 0b to  
1110 0000 0b. i.e., limit the amount of adjustment to ±15%. The remaining ±5% headroom allows for the ADC's  
own full scale variation .A gain adjustment does not require ADC re-calibration.  
POR State: 1000 0000 0b (no adjustment)  
Must be set to 1b  
Bits 6:0  
Table 8. Q-Channel Offset  
Addr: Ah (1010b)  
W only (0x007F)  
D15  
D14  
D13  
D12  
D11  
D10  
D9  
D8  
(MSB)  
Offset Value  
(LSB)  
D7  
D6  
1
D5  
1
D4  
1
D3  
1
D2  
1
D1  
1
D0  
1
Sign  
Bit 15:8  
Offset Value. The input offset of the Q-Channel ADC is adjusted linearly and monotonically by the value in this  
field. 00h provides a nominal zero offset, while FFh provides a nominal 45 mV of offset. Thus, each code step  
provides about 0.176 mV of offset.  
POR State: 0000 0000b  
Bit 7  
Sign bit. 0b gives positive offset, 1b gives negative offset.  
POR State: 0b  
Bit 6:0  
Must be set to 1b  
Table 9. Q-Channel Full-Scale Voltage Adjust  
Addr: Bh (1011b)  
W only (0x807F)  
D15  
D14  
D13  
D12  
D11  
D10  
D9  
D8  
(MSB)  
Adjust Value  
D7  
D6  
1
D5  
1
D4  
1
D3  
1
D2  
1
D1  
1
D0  
1
(LSB)  
Bit 15:7  
Full Scale Voltage Adjust Value. The input full-scale voltage of the Q-Channel ADC is adjusted linearly and  
monotonically from the nominal 700 mVP-P differential by the value in this field.  
0000 0000 0  
1000 0000 0  
1111 1111 1  
560mVP-P  
700mVP-P  
840mVP-P  
For best performance, it is recommended that the value in this field be limited to the range of 0110 0000 0b to  
1110 0000 0b. i.e., limit the amount of adjustment to ±15%. The remaining ±5% headroom allows for the ADC's  
own full scale variation .A gain adjustment does not require ADC re-calibration.  
POR State: 1000 0000 0b (no adjustment)  
Must be set to 1b  
Bits 6:0  
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Table 10. DES Enable  
Addr: Dh (1101b)  
W only (0x3FFF)  
D15  
D14  
D13  
1
D12  
1
D11  
1
D10  
1
D9  
1
D8  
1
DEN  
ACP  
D7  
1
D6  
1
D5  
1
D4  
1
D3  
1
D2  
1
D1  
1
D0  
1
Bit 15  
Bit 14  
DES Enable. Setting this bit to 1b enables the Dual Edge Sampling mode. In this mode the ADCs in this device  
are used to sample and convert the same analog input in a time-interleaved manner, accomplishing a sampling  
rate of twice the input clock rate. When this bit is set to 0b, the device operates in the normal dual channel  
mode.  
POR State: 0b  
Automatic Clock Phase (ACP) Control. Setting this bit to 1b enables the Automatic Clock Phase Control. In this  
mode the DES Coarse and Fine manual controls are disabled. A phase detection circuit continually adjusts the  
I and Q sampling edges to be 180 degrees out of phase. When this bit is set to 0b, the sample (input) clock  
delay between the I and Q channels is set manually using the DES Coarse and Fine Adjust registers. (See  
Dual Edge Sampling for important application information)Using the ACP Control option is recommended  
over the manual DES settings.  
POR State: 0b  
Bits 13:0  
Must be set to 1b  
Table 11. DES Coarse Adjust  
Addr: Eh (1110b)  
W only (0x07FF)  
D15  
IS  
D14  
D13  
D12  
D11  
D10  
1
D9  
1
D8  
1
ADS  
CAM  
D7  
1
D6  
1
D5  
1
D4  
1
D3  
1
D2  
1
D1  
1
D0  
1
Bit 15  
Bit 14  
Input Select. When this bit is set to 0b the "I" input is operated upon by both ADCs. When this bit is set to 1b  
the "Q" input is operated on by both ADCs.  
POR State: 0b  
Adjust Direction Select. When this bit is set to 0b, the programmed delays are applied to the "I" channel sample  
clock while the "Q" channel sample clock remains fixed. When this bit is set to 1b, the programmed delays are  
applied to the "Q" channel sample clock while the "I" channel sample clock remains fixed.  
POR State: 0b  
Bits 13:11  
Bits 10:0  
Coarse Adjust Magnitude. Each code value in this field delays either the "I" channel or the "Q" channel sample  
clock (as determined by the ADS bit) by approximately 20 picoseconds. A value of 000b in this field causes  
zero adjustment.  
POR State: 000b  
Must be set to 1b  
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Table 12. DES Fine Adjust  
Addr: Fh (1111b)  
W only (0x007F)  
D15  
(MSB)  
D14  
D13  
D12  
D11  
D10  
D9  
D8  
FAM  
D7  
D6  
D5  
D4  
D3  
1
D2  
1
D1  
1
D0  
1
(LSB)  
1
1
1
Bits 15:7  
Fine Adjust Magnitude. Each code value in this field delays either the "I" channel or the "Q" channel sample  
clock (as determined by the ADS bit of the DES Coarse Adjust Register) by approximately 0.1 ps. A value of  
0000 0000 0b in this field causes zero adjustment. Note that the amount of adjustment achieved with each  
code will vary with the device conditions as well as with the Coarse Adjustment value chosen.  
POR State: 0000 0000 0b  
Must be set to 1b  
Bit 6:0  
Note Regarding Extended Mode Offset Correction  
When using the I or Q channel Offset Adjust registers, the following information should be noted.  
For offset values of +0000 0000 and -0000 0000, the actual offset is not the same. By changing only the sign bit  
in this case, an offset step in the digital output code of about 1/10th of an LSB is experienced. This is shown  
more clearly in the Figure below.  
Figure 30. Extended Mode Offset Behavior  
MULTIPLE ADC SYNCHRONIZATION  
The ADC08D500 has the capability to precisely reset its sampling clock input to DCLK output relationship as  
determined by the user-supplied DCLK_RST pulse. This allows multiple ADCs in a system to have their DCLK  
(and data) outputs transition at the same time with respect to the shared CLK input that they all use for sampling.  
The DCLK_RST signal must observe some timing requirements that are shown in Figure 6, Figure 7, and  
Figure 8 of the Timing Diagrams. The DCLK_RST pulse must be of a minimum width and its deassertion edge  
must observe setup and hold times with respect to the CLK input rising edge. These times are specified in the  
AC Electrical Characteristics Table.  
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The DCLK_RST signal can be asserted asynchronous to the input clock If DCLK_RST is asserted, the DCLK  
output is held in a designated state. The state in which DCLK is held during the reset period is determined by the  
mode of operation (SDR/DDR) and the setting of the Output Edge configuration pin or bit. (Refer to Figure 6,  
Figure 8, and Figure 8 for the DCLK reset conditions). Therefore depending upon when the DCLK_RST signal is  
asserted, there may be a narrow pulse on the DCLK line during this reset event. When the DCLK_RST signal is  
de-asserted in synchronization with the CLK rising edge, the next CLK falling edge synchronizes the DCLK  
output with those of other ADC08D500s in the system. The DCLK output is enabled again after a constant delay  
which is equal to the CLK input to DCLK output delay (tAD). The device always exhibits this delay characteristic in  
normal operation.  
The DCLK-RST pin should NOT be brought high while the calibration process is running (while CalRun is high).  
Doing so could cause a digital glitch in the digital circuitry, resulting in corruption and invalidation of the  
calibration.  
Applications Information  
THE REFERENCE VOLTAGE  
The voltage reference for the ADC08D500 is derived from a 1.254V bandgap reference which is made available  
at pin 31, VBG for user convenience and has an output current capability of ±100 μA and should be buffered if  
more current than this is required.  
The internal bandgap-derived reference voltage has a nominal value of 650 mV or 870 mV, as determined by the  
FSR pin and described in The Analog Inputs.  
There is no provision for the use of an external reference voltage, but the full-scale input voltage can be adjusted  
through a Configuration Register in the Extended Control mode, as explained in NORMAL/EXTENDED  
CONTROL.  
Differential input signals up to the chosen full-scale level will be digitized to 8 bits. Signal excursions beyond the  
full-scale range will be clipped at the output. These large signal excursions will also activate the OR output for  
the time that the signal is out of range. See Out Of Range (OR) Indication.  
One extra feature of the VBG pin is that it can be used to raise the common mode voltage level of the LVDS  
outputs. The output offset voltage (VOS) is typically 800mV when the VBG pin is used as an output or left  
unconnected. To raise the LVDS offset voltage to a typical value of 1200mV the VBG pin can be connected  
directly to the supply rails.  
THE ANALOG INPUT  
The analog input is a differential one to which the signal source may be a.c. coupled or d.c. coupled. The full-  
scale input range is selected with the FSR pin to be 650 mVP-P or 870 mVP-P, or can be adjusted to values  
between 560 mVP-P and 840 mVP-P in the Extended Control mode through the Serial Interface. For best  
performance, it is recommended that the full-scale range be kept between 595 mVP-P and 805 mVP-P in the  
Extended Control mode.  
Table 13 gives the input to output relationship with the FSR pin high and the normal (non-extended) mode is  
used. With the FSR pin grounded, the millivolt values in Table 13 are reduced to 75% of the values indicated. In  
the Enhanced Control Mode, these values will be determined by the full scale range and offset settings in the  
Control Registers.  
Table 13. Differential Input To Output Relationship  
(Non-Extended Control Mode, FSR High)  
VIN  
+
VIN  
Output Code  
0000 0000  
0100 0000  
V
CM 217.5mV  
VCM + 217.5mV  
VCM + 109mV  
V
CM 109mV  
0111 1111 /  
1000 0000  
VCM  
VCM  
VCM + 109 mV  
VCM + 217.5mV  
V
CM 109mV  
1100 0000  
1111 1111  
VCM 217.5mV  
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The buffered analog inputs simplify the task of driving these inputs and the RC pole that is generally used at  
sampling ADC inputs is not required. If it is desired to use an amplifier circuit before the ADC, use care in  
choosing an amplifier with adequate noise and distortion performance and adequate gain at the frequencies used  
for the application.  
Note that a precise d.c. common mode voltage must be present at the ADC inputs. This common mode voltage,  
VCMO, is provided on-chip when a.c. input coupling is used and the input signal is a.c. coupled to the ADC.  
When the inputs are a.c. coupled, the VCMO output must be grounded, as shown in Figure 31. This causes the  
on-chip VCMO voltage to be connected to the inputs through on-chip 50k-Ohm resistors.  
NOTE  
An Analog input channel that is not used (e.g. in DES Mode) should be left floating when  
the inputs are a.c. coupled. Do not connect an unused analog input to ground.  
C
couple  
V
+
IN  
C
couple  
V -  
IN  
V
CMO  
ADC08D500  
Figure 31. Differential Input Drive  
When the d.c. coupled mode is used, a common mode voltage must be provided at the differential inputs. This  
common mode voltage should track the VCMO output pin. Note that the VCMO output potential will change with  
temperature. The common mode output of the driving device should track this change.  
NOTE  
An analog input channel that is not used (e.g. in DES Mode) should be tied to the VCMO  
voltage when the inputs are d.c. coupled. Do not connect unused analog inputs to ground.  
Full-scale distortion performance falls off rapidly as the input common mode voltage deviates from VCMO  
This is a direct result of using a very low supply voltage to minimize power. Keep the input common  
voltage within 50 mV of VCMO  
.
.
Performance is as good in the d.c. coupled mode as it is in the a.c. coupled mode, provided the input  
common mode voltage at both analog inputs remain within 50 mV of VCMO  
.
If d.c. coupling is used, it is best to servo the input common mode voltage with VCMO to maintain optimum  
performance. An example of this type of circuit is shown in Figure 32.  
3.3V  
LMH6555  
R
F1  
R
T2  
V
V
-
IN  
R
G1  
50W  
-
Signal  
Input  
50W  
+
R
T1  
R
V
+
IN  
G2  
50W  
R
F2  
CM_REF  
+
-
V
CMO  
LMV321  
Figure 32. Example of Servoing the Analog Input with VCMO  
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One such circuit should be used in front of the VIN+ input and another in front of the VINinput. In that figure,  
RD1, RD2 and RD3 are used to divide the VCMO potential so that, after being gained up by the amplifier, the input  
common mode voltage is equal to VCMO from the ADC. RD1 and RD2 are split to allow the bypass capacitor to  
isolate the input signal from VCMO. RIN, RD2 and RD3 will divide the input signal, if necessary. Capacitor "C" in  
Figure 32 should be chosen to keep any component of the input signal from affecting VCMO  
.
Be sure that the current drawn from the VCMO output does not exceed 100 μA.  
The Input impedance in the d.c. coupled mode (VCMO pin not grounded) consists of a precision 100resistor  
between VIN+ and VINand a capacitance from each of these inputs to ground. In the a.c. coupled mode the  
input appears the same except there is also a resistor of 50K between each analog input pin and the VCMO  
potential.  
Driving the inputs beyond full scale will result in a saturation or clipping of the reconstructed output.  
Handling Single-Ended Input Signals  
There is no provision for the ADC08D500 to adequately process single-ended input signals. The best way to  
handle single-ended signals is to convert them to differential signals before presenting them to the ADC. The  
easiest way to accomplish single-ended to differential signal conversion is with an appropriate balun-connected  
transformer, as shown in Figure 33.  
C
couple  
V
IN  
+
50W  
Source  
100W  
1:2 Balun  
V
IN  
-
C
couple  
ADC08D500  
Figure 33. Single-Ended to Differential signal conversion with a balun-connected transformer  
The 100 Ohm external resistor placed across the output terminals of the balun in parallel with the ADC08D1000's  
on-chip 100 Ohm resistor makes a 50 Ohms differential impedance at the balun output. Or, 25 Ohms to virtual  
ground at each of the balun output terminals.  
Looking into the balun, the source sees the impedance of the first coil in series with the impedance at the output  
of that coil. Since the transformer has a 1:1 turns ratio, the impedance across the first coil is exactly the same as  
that at the output of the second coil, namely 25 Ohms to virtual ground. So, the 25 Ohms across the first coil in  
series with the 25 Ohms at its output gives 50 Ohms total impedance to match the source.  
Out Of Range (OR) Indication  
When the conversion result is clipped the Out of Range output is activated such that OR+ goes high and OR-  
goes low. This output is active as long as accurate data on either or both of the buses would be outside the  
range of 00h to FFh.  
Full-Scale Input Range  
As with all A/D Converters, the input range is determined by the value of the ADC's reference voltage. The  
reference voltage of the ADC08D500 is derived from an internal band-gap reference. The FSR pin controls the  
effective reference voltage of the ADC08D500 such that the differential full-scale input range at the analog inputs  
is 870 mVP-P with the FSR pin high, or is 650 mVP-P with FSR pin low. Best SNR is obtained with FSR high, but  
better distortion and SFDR are obtained with the FSR pin low.  
THE CLOCK INPUTS  
The ADC08D500 has differential LVDS clock inputs, CLK+ and CLK-, which must be driven with a differential,  
a.c. coupled clock signal as indicated in Figure 34. Although the ADC08D500 is tested and its performance is  
specified with a differential 500 MHz clock, it typically will function well with clock frequencies indicated in the  
Electrical Characteristics Table. The clock inputs are internally terminated and biased.  
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Operation up to the sample rates indicated in the Electrical Characteristics Table is typically possible if the  
maximum ambient temperatures indicated are not exceeded. Operating at higher sample rates than indicated for  
the given ambient temperature may result in reduced device reliability and product lifetime. This is because of the  
higher power consumption and die temperatures at high sample rates. Important also for reliability is proper  
thermal management . See Thermal Management.  
C
C
couple  
couple  
CLK+  
CLK-  
ADC08D500  
Figure 34. Differential (LVDS) Clock Connection  
The differential Clock line pair should have a characteristic impedance of 100and be terminated at the clock  
source in that (100) characteristic impedance. The clock line should be as short and as direct as possible. The  
ADC08D500 clock input is internally terminated with an untrimmed 100resistor.  
Insufficient clock levels will result in poor dynamic performance. Excessively high clock levels could cause a  
change in the analog input offset voltage. To avoid these problems, keep the clock level within the range  
specified in the Electrical Characteristics Table.  
The low and high times of the input clock signal can affect the performance of any A/D Converter. The  
ADC08D1000 features a duty cycle clock correction circuit which can maintain performance over temperature  
even in DES mode. The ADC will meet its performance specification if the input clock high and low times are  
maintained within the range (20/80% ratio) as specified in the Electrical Characteristics Table.  
High speed, high performance ADCs such as the ADC08D500 require a very stable clock signal with minimum  
phase noise or jitter. ADC jitter requirements are defined by the ADC resolution (number of bits), maximum ADC  
input frequency and the input signal amplitude relative to the ADC input full scale range. The maximum jitter (the  
sum of the jitter from all sources) allowed to prevent a jitter-induced reduction in SNR is found to be  
tJ(MAX) = (VIN(P-P) / VINFSR) x (1/(2(N+1) x π x fIN))  
(1)  
where tJ(MAX) is the rms total of all jitter sources in seconds, VIN(P-P) is the peak-to-peak analog input signal, VINFSR  
is the full-scale range of the ADC, "N" is the ADC resolution in bits and fIN is the maximum input frequency, in  
Hertz, to the ADC analog input.  
Note that the maximum jitter described above is the arithmetic sum of the jitter from all sources, including that in  
the ADC clock, that added by the system to the ADC clock and input signals and that added by the ADC itself.  
Since the effective jitter added by the ADC is beyond user control, the best the user can do is to keep the sum of  
the externally added clock jitter and the jitter added by the analog circuitry to the analog signal to a minimum.  
Clock amplitudes above those specified in the Electrical Characteristics Table may result in increased input offset  
voltage. This would cause the converter to produce an output code other than the expected 127/128 when both  
input pins are at the same potential.  
CONTROL PINS  
Six control pins (without the use of the serial interface) provide a wide range of possibilities in the operation of  
the ADC08D500 and facilitate its use. These control pins provide Full-Scale Input Range setting, Self Calibration,  
Calibration Delay, Output Edge Synchronization choice, LVDS Output Level choice and a Power Down feature.  
Full-Scale Input Range Setting  
The input full-scale range can be selected to be either 650 mVP-P or 870 mVP-P, as selected with the FSR control  
input (pin 14) in the Normal Mode of operation. In the Extended Control Mode, the input full-scale range may be  
set to be anywhere from 560 mVP-P to 840 mVP-P. See THE ANALOG INPUT for more information.  
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Self Calibration  
The ADC08D500 self-calibration must be run to achieve specified performance. The calibration procedure is run  
upon power-up and can be run any time on command. The calibration procedure is exactly the same whether  
there is a clock present upon power up or if the clock begins some time after application of power. The CalRun  
output indicator is high while a calibration is in progress. Note that DCLK outputs are not active during a  
calibration cycle, therefore it is not recommended as a system clock.  
Power-On Calibration  
Power-on calibration begins after a time delay following the application of power. This time delay is determined  
by the setting of CalDly, as described in the Calibration Delay Section, below.  
The calibration process will be not be performed if the CAL pin is high at power up. In this case, the calibration  
cycle will not begin until the on-command calibration conditions are met. The ADC08D500 will function with the  
CAL pin held high at power up, but no calibration will be done and performance will be impaired. A manual  
calibration, however, may be performed after powering up with the CAL pin high. See On-Command Calibration.  
The internal power-on calibration circuitry comes up in an unknown logic state. If the clock is not running at  
power up and the power on calibration circuitry is active, it will hold the analog circuitry in power down and the  
power consumption will typically be less than 200 mW. The power consumption will be normal after the clock  
starts.  
On-Command Calibration  
An on-command calibration may be run at any time in NORMAL (non-DES) mode only. Do not run a calibration  
while operating the ADC in Auto DES Mode.  
If the ADC is operating in Auto DES mode and a calibration cycle is required then the controlling application  
should bring the ADC into normal (non DES) mode before an On Command calibration is initiated. Once  
calibration has completed, the ADC can be put back into Auto DES mode.  
To initiate an on-command calibration, bring the CAL pin high for a minimum of 80 input clock cycles after it has  
been low for a minimum of 80 input clock cycles. Holding the CAL pin high upon power up will prevent execution  
of power-on calibration until the CAL pin is low for a minimum of 80 input clock cycles, then brought high for a  
minimum of another 80 input clock cycles. The calibration cycle will begin 80 input clock cycles after the CAL pin  
is thus brought high. The CalRun signal should be monitored to determine when the calibration cycle has  
completed. When an on-command calibration is executed, the CAL pin must be held low for 80 input clock cycles  
and then low for 80 input clock cycles before the CalRun pin is activated to indicate that a calibration is taking  
place. When the CalRun pin is activated, all outputs including the DCLK outputs are deactivated and enter a high  
impedance state. After the calibration cycle is finished and the CalRun pin is low, the outputs, including DCLK,  
are active again but require a short settling period, typically around 100ns. Because the DCLK outputs are not  
activated during a calibration cycle, they are not recommended for use as a system clock.  
The minimum 80 input clock cycle sequences are required to ensure that random noise does not cause a  
calibration to begin when it is not desired. As mentioned in Self-Calibration for best performance, a self  
calibration should be performed 20 seconds or more after power up and repeated when the operating  
temperature changes significantly according to the particular system performance requirements. ENOB drops  
slightly as junction temperature increases and executing a new self calibration cycle will essentially eliminate the  
change.  
Calibration Delay  
The CalDly input (pin 127) is used to select one of two delay times after the application of power to the start of  
calibration, as described in Self-Calibration. The calibration delay values allow the power supply to come up and  
stabilize before calibration takes place. With no delay or insufficient delay, calibration would begin before the  
power supply is stabilized at its operating value and result in non-optimal calibration coefficients. If the PD pin is  
high upon power-up, the calibration delay counter will be disabled until the PD pin is brought low. Therefore,  
holding the PD pin high during power up will further delay the start of the power-up calibration cycle. The best  
setting of the CalDly pin depends upon the power-on settling time of the power supply.  
Note that the calibration delay selection is not possible in the Extended Control mode and the short delay time is  
used.  
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Output Edge Synchronization  
DCLK signals are available to help latch the converter output data into external circuitry. The output data can be  
synchronized with either edge of these clock signals. That is, the output data transition can be set to occur with  
either the rising edge or the falling edge of the DCLK signal, so that either edge of that clock signal can be used  
to latch the output data into the receiving circuit.  
When OutEdge (pin 4) is high, the output data is synchronized with (changes with) the rising edge of the DCLK+  
(pin 82). When OutEdge is low, the output data is synchronized with the falling edge of DCLK+.  
At the very high speeds of which the ADC08D500 is capable, slight differences in the lengths of the clock and  
data lines can mean the difference between successful and erroneous data capture. The OutEdge pin is used to  
capture data on the DCLK edge that best suits the application circuit and layout.  
LVDS Output Level Control  
The output level can be set to one of two levels with OutV (pin3). The strength of the output drivers is greater  
with OutV high. With OutV low there is less power consumption in the output drivers, but the lower output level  
means decreased noise immunity.  
For short LVDS lines and low noise systems, satisfactory performance may be realized with the FSR input low. If  
the LVDS lines are long and/or the system in which the ADC08D500 is used is noisy, it may be necessary to tie  
the FSR pin high.  
Dual Edge Sampling  
NOTE  
When using the ADC in Extended Control Mode, the Configuration Register must only be  
written when the DES Enable bit = 0. Writing to the Configuration Register when the DES  
Enable bit = 1 can cause the internal DES clock generation circuitry to stop.  
The Dual Edge Sampling (DES) feature causes one of the two input pairs to be routed to both ADCs. The other  
input pair is deactivated. One of the ADCs samples the input signal on one clock edge, the other samples the  
input signal on the other clock edge. The result is a 1:4 demultiplexed output with a sample rate that is twice the  
input clock frequency.  
To use this feature in the non-enhanced control mode, allow pin 127 to float and the signal at the "I" channel  
input will be sampled by both converters. The Calibration Delay will then only be a short delay.  
In the enhanced control mode, either input may be used for dual edge sampling. See Dual-Edge Sampling.  
NOTE  
1) For the Extended Control Mode - When using the Automatic Clock Phase Control  
feature in dual edge sampling mode, it is important that the automatic phase control is  
disabled (set bit 14 of DES Enable register Dh to 0) before the ADC is powered up. Not  
doing so may cause the device not to wake up from the power down state.  
2) For the Non-Extended Control Mode - When the ADC08D1000 is powered up and DES  
mode is required, ensure that pin 127 (CalDly/DES/SCS) is initially pulled low during or  
after the power up sequence. The pin can then be allowed to float or be tied to VA / 2 to  
enter the DES mode. This will ensure that the part enters the DES mode correctly.  
3) The automatic phase control should also be disabled if the input clock is interrupted or  
stopped for any reason. This is also the case if a large abrupt change in the clock  
frequency occurs.  
4) If a calibration of the ADC is required in Auto DES mode, the device must be returned  
to the Normal Mode of operation before performing a calibration cycle. Once the  
Calibration has been completed, the device can be returned to the Auto DES mode and  
operation can resume.  
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Power Down Feature  
The Power Down pins (PD and PDQ) allow the ADC08D500 to be entirely powered down (PD) or the "Q"  
channel to be powered down and the "I" channel to remain active. See Power Down for details on the power  
down feature.  
The digital data (+/-) output pins are put into a high impedance state when the PD pin for the respective channel  
is high. Upon return to normal operation, the pipeline will contain meaningless information and must be flushed.  
If the PD input is brought high while a calibration is running, the device will not go into power down until the  
calibration sequence is complete. However, if power is applied and PD is already high, the device will not begin  
the calibration sequence until the PD input goes low. If a manual calibration is requested while the device is  
powered down, the calibration will not begin at all. That is, the manual calibration input is completely ignored in  
the power down state.  
THE DIGITAL OUTPUTS  
The ADC08D1000 demultiplexes the output data of each of the two ADCs on the die onto two LVDS output  
buses (total of four buses, two for each ADC). For each of the two converters, the results of successive  
conversions started on the odd falling edges of the CLK+ pin are available on one of the two LVDS buses, while  
the results of conversions started on the even falling edges of the CLK+ pin are available on the other LVDS bus.  
This means that, the word rate at each LVDS bus is 1/2 the ADC08D1000 input clock rate and the two buses  
must be multiplexed to obtain the entire 1 GSPS conversion result.  
Since the minimum recommended input clock rate for this device is 200 MSPS (normal non DES mode), the  
effective rate can be reduced to as low as 100 MSPS by using the results available on just one of the the two  
LVDS buses and a 200 MHz input clock, decimating the 200 MSPS data by two.  
There is one LVDS output clock pair (DCLK+/-) available for use to latch the LVDS outputs on all buses. Whether  
the data is sent at the rising or falling edge of DCLK is determined by the sense of the OutEdge pin, as described  
in Output Edge Synchronization.  
DDR (Double Data Rate) clocking can also be used. In this mode a word of data is presented with each edge of  
DCLK, reducing the DCLK frequency to 1/4 the input clock frequency. See the Timing Diagram section for  
details.  
The OutV pin is used to set the LVDS differential output levels. See LVDS Output Level Control.  
The output format is Offset Binary. Accordingly, a full-scale input level with VIN+ positive with respect to VINwill  
produce an output code of all ones, a full-scale input level with VINpositive with respect to VIN+ will produce an  
output code of all zeros and when VIN+ and VINare equal, the output code will vary between codes 127 and  
128.  
POWER CONSIDERATIONS  
A/D converters draw sufficient transient current to corrupt their own power supplies if not adequately bypassed. A  
33 µF capacitor should be placed within an inch (2.5 cm) of the A/D converter power pins. A 0.1 µF capacitor  
should be placed as close as possible to each VA pin, preferably within one-half centimeter. Leadless chip  
capacitors are preferred because they have low lead inductance.  
The VA and VDR supply pins should be isolated from each other to prevent any digital noise from being coupled  
into the analog portions of the ADC. A ferrite choke, such as the JW Miller FB20009-3B, is recommended  
between these supply lines when a common source is used for them.  
As is the case with all high speed converters, the ADC08D500 should be assumed to have little power supply  
noise rejection. Any power supply used for digital circuitry in a system where a lot of digital power is being  
consumed should not be used to supply power to the ADC08D500. The ADC supplies should be the same  
supply used for other analog circuitry, if not a dedicated supply.  
Supply Voltage  
The ADC08D500 is specified to operate with a supply voltage of 1.9V ±0.1V. It is very important to note that,  
while this device will function with slightly higher supply voltages, these higher supply voltages may reduce  
product lifetime.  
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No pin should ever have a voltage on it that is in excess of the supply voltage or below ground by more than 150  
mV, not even on a transient basis. This can be a problem upon application of power and power shut-down. Be  
sure that the supplies to circuits driving any of the input pins, analog or digital, do not come up any faster than  
does the voltage at the ADC08D500 power pins.  
The Absolute Maximum Ratings should be strictly observed, even during power up and power down. A power  
supply that produces a voltage spike at turn-on and/or turn-off of power can destroy the ADC08D500. The circuit  
of Figure 35 will provide supply overshoot protection.  
Many linear regulators will produce output spiking at power-on unless there is a minimum load provided. Active  
devices draw very little current until their supply voltages reach a few hundred millivolts. The result can be a turn-  
on spike that can destroy the ADC08D500, unless a minimum load is provided for the supply. The 100resistor  
at the regulator output provides a minimum output current during power-up to ensure there is no turn-on spiking.  
In the circuit of Figure 35, an LM317 linear regulator is satisfactory if its input supply voltage is 4V to 5V . If a  
3.3V supply is used, an LM1086 linear regulator is recommended.  
Linear  
Regulator  
1.9V  
to ADC  
V
IN  
+
10 mF  
210  
110  
+
33 mF  
100  
+
10 mF  
Figure 35. Non-Spiking Power Supply  
The output drivers should have a supply voltage, VDR, that is within the range specified in the Operating Ratings  
table. This voltage should not exceed the VA supply voltage and should never spice to a voltage greater than (VA  
+ 100 mV).  
If the power is applied to the device without a clock signal present, the current drawn by the device might be  
below 200 mA. This is because the ADC08D500 gets reset through clocked logic and its initial state is random. If  
the reset logic comes up in the "on" state, it will cause most of the analog circuitry to be powered down, resulting  
in less than 100 mA of current draw. This current is greater than the power down current because not all of the  
ADC is powered down. The device current will be normal after the clock is established.  
Thermal Management  
The ADC08D500 is capable of impressive speeds and performance at very low power levels for its speed.  
However, the power consumption is still high enough to require attention to thermal management. For reliability  
reasons, the die temperature should be kept to a maximum of 130°C. That is, TA (ambient temperature) plus  
ADC power consumption times θJA (junction to ambient thermal resistance) should not exceed 130°C. This is not  
a problem if the ambient temperature is kept to a maximum of +85°C as specified in the Operating Ratings  
section.  
Please note that the following are general recommendations for mounting exposed pad devices onto a PCB. This  
should be considered the starting point in PCB and assembly process development. It is recommended that the  
process be developed based upon past experience in package mounting.  
The package of the ADC08D500 has an exposed pad on its back that provides the primary heat removal path as  
well as excellent electrical grounding to the printed circuit board. The land pattern design for lead attachment to  
the PCB should be the same as for a conventional HLQFP, but the exposed pad must be attached to the board  
to remove the maximum amount of heat from the package, as well as to ensure best product parametric  
performance.  
To maximize the removal of heat from the package, a thermal land pattern must be incorporated on the PC  
board within the footprint of the package. The exposed pad of the device must be soldered down to ensure  
adequate heat conduction out of the package. The land pattern for this exposed pad should be at least as large  
as the 5 x 5 mm of the exposed pad of the package and be located such that the exposed pad of the device is  
entirely over that thermal land pattern. This thermal land pattern should be electrically connected to ground. A  
clearance of at least 0.5 mm should separate this land pattern from the mounting pads for the package pins.  
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5.0 mm, min  
0.25 mm, typ  
0.33 mm, typ  
1.2 mm, typ  
Figure 36. Recommended Package Land Pattern  
Since a large aperture opening may result in poor release, the aperture opening should be subdivided into an  
array of smaller openings, similar to the land pattern of Figure 36.  
To minimize junction temperature, it is recommended that a simple heat sink be built into the PCB. This is done  
by including a copper area of about 2 square inches (6.5 square cm) on the opposite side of the PCB. This  
copper area may be plated or solder coated to prevent corrosion, but should not have a conformal coating, which  
could provide some thermal insulation. Thermal vias should be used to connect these top and bottom copper  
areas. These thermal vias act as "heat pipes" to carry the thermal energy from the device side of the board to the  
opposite side of the board where it can be more effectively dissipated. The use of 9 to 16 thermal vias is  
recommended.  
The thermal vias should be placed on a 1.2 mm grid spacing and have a diameter of 0.30 to 0.33 mm. These  
vias should be barrel plated to avoid solder wicking into the vias during the soldering process as this wicking  
could cause voids in the solder between the package exposed pad and the thermal land on the PCB. Such voids  
could increase the thermal resistance between the device and the thermal land on the board, which would cause  
the device to run hotter.  
If it is desired to monitor die temperature, a temperature sensor may be mounted on the heat sink area of the  
board near the thermal vias. .Allow for a thermal gradient between the temperature sensor and the ADC08D500  
die of θJ-PAD times typical power consumption = 2.8 x 1.6 = 4.5°C. Allowing for a 5.5°C (including an extra 1°C)  
temperature drop from the die to the temperature sensor, then, would mean that maintaining a maximum pad  
temperature reading of 124.5°C will ensure that the die temperature does not exceed 130°C, assuming that the  
exposed pad of the ADC08D500 is properly soldered down and the thermal vias are adequate. (The inaccuracy  
of the temperature sensor is in addition to the above calculation).  
LAYOUT AND GROUNDING  
Proper grounding and routing of all signals are essential to ensure accurate conversion. A single ground plane  
should be used instead of splitting the ground plane into analog and digital areas.  
Since digital switching transients are composed largely of high frequency components, the skin effect tells us that  
total ground plane copper weight will have little effect upon the logic-generated noise. Total surface area is more  
important than is total ground plane volume. Coupling between the typically noisy digital circuitry and the  
sensitive analog circuitry can lead to poor performance that may seem impossible to isolate and remedy. The  
solution is to keep the analog circuitry well separated from the digital circuitry.  
High power digital components should not be located on or near any linear component or power supply trace or  
plane that services analog or mixed signal components as the resulting common return current path could cause  
fluctuation in the analog input “ground” return of the ADC, causing excessive noise in the conversion result.  
Generally, we assume that analog and digital lines should cross each other at 90° to avoid getting digital noise  
into the analog path. In high frequency systems, however, avoid crossing analog and digital lines altogether.  
Clock lines should be isolated from ALL other lines, analog AND digital. The generally accepted 90° crossing  
should be avoided as even a little coupling can cause problems at high frequencies. Best performance at high  
frequencies is obtained with a straight signal path.  
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The analog input should be isolated from noisy signal traces to avoid coupling of spurious signals into the input.  
This is especially important with the low level drive required of the ADC08D500. Any external component (e.g., a  
filter capacitor) connected between the converter's input and ground should be connected to a very clean point in  
the analog ground plane. All analog circuitry (input amplifiers, filters, etc.) should be separated from any digital  
components.  
DYNAMIC PERFORMANCE  
The ADC08D500 is a.c. tested and its dynamic performance is specified. To meet the published specifications  
and avoid jitter-induced noise, the clock source driving the CLK input must exhibit low rms jitter. The allowable  
jitter is a function of the input frequency and the input signal level, as described in THE CLOCK INPUTS.  
It is good practice to keep the ADC clock line as short as possible, to keep it well away from any other signals  
and to treat it as a transmission line. Other signals can introduce jitter into the clock signal. The clock signal can  
also introduce noise into the analog path if not isolated from that path.  
Best dynamic performance is obtained when the exposed pad at the back of the package has a good connection  
to ground. This is because this path from the die to ground is a lower impedance than offered by the package  
pins.  
USING THE SERIAL INTERFACE  
The ADC08D500 may be operated in the non-extended control (non-Serial Interface) mode or in the extended  
control mode. Table 14 and Table 15 describe the functions of pins 3, 4, 14 and 127 in the non-extended control  
mode and the extended control mode, respectively.  
Non-Extended Control Mode Operation  
Non-extended control mode operation means that the Serial Interface is not active and all controllable functions  
are controlled with various pin settings. That is, the full-scale range, single-ended or differential input and input  
coupling (a.c. or d.c.) are all controlled with pin settings. The non-extended control mode is used by setting pin  
14 high or low, as opposed to letting it float. Table 14 indicates the pin functions of the ADC08D500 in the non-  
extended control mode.  
Table 14. Non-Extended Control Mode Operation  
(Pin 14 High or Low)  
Pin  
3
Low  
High  
Floating  
0.51 VP-P Output  
OutEdge = Neg  
CalDly Low  
0.71 VP-P Output  
OutEdge = Pos  
CalDly High  
n/a  
4
DDR  
DES  
127  
14  
650 mVP-P input range  
870 mVP-P input range  
Extended Control Mode  
Pin 3 can be either high or low in the non-extended control mode. Pin 14 must not be left floating to select this  
mode. See NORMAL/EXTENDED CONTROL for more information.  
Pin 4 can be high or low or can be left floating in the non-extended control mode. In the non-extended control  
mode, pin 4 high or low defines the edge at which the output data transitions. See Output Edge Synchronization  
for more information. If this pin is floating, the output clock (DCLK) is a DDR (Double Data Rate) clock (see  
Double Data Rate) and the output edge synchronization is irrelevant since data is clocked out on both DCLK  
edges.  
Pin 127, if it is high or low in the non-extended control mode, sets the calibration delay. If pin 127 is floating, the  
calibration delay is the same as it would be with this pin low and the converter performs dual edge sampling  
(DES).  
Table 15. Extended Control Mode Operation  
(Pin 14 Floating)  
Pin  
3
Function  
SCLK (Serial Clock)  
SDATA (Serial Data)  
4
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Table 15. Extended Control Mode Operation  
(Pin 14 Floating) (continued)  
Pin  
Function  
127  
SCS (Serial Interface Chip Select)  
COMMON APPLICATION PITFALLS  
Failure to write all register locations when using extended control mode. When using the serial interface, all  
8 user registers must be written at least once with the default or desired values before calibration and  
subsequent use of the ADC. In addition, the first write to the DES Enable register (Dh) must load the default  
value (0x3FFFh). Once all registers have been written once, other desired settings, including enabling DES can  
be loaded.  
Driving the inputs (analog or digital) beyond the power supply rails. For device reliability, no input should  
not go more than 150 mV below the ground pins or 150 mV above the supply pins. Exceeding these limits on  
even a transient basis may not only cause faulty or erratic operation, but may impair device reliability. It is not  
uncommon for high speed digital circuits to exhibit undershoot that goes more than a volt below ground.  
Controlling the impedance of high speed lines and terminating these lines in their characteristic impedance  
should control overshoot.  
Care should be taken not to overdrive the inputs of the ADC08D500. Such practice may lead to conversion  
inaccuracies and even to device damage.  
Incorrect analog input common mode voltage in the d.c. coupled mode. As discussed in The Analog Inputs  
and THE ANALOG INPUT, the Input common mode voltage must remain within 50 mV of the VCMO output, which  
has a variability with temperature that must also be tracked. Distortion performance will be degraded if the input  
common mode voltage is more than 50 mV from VCMO  
.
Using an inadequate amplifier to drive the analog input. Use care when choosing a high frequency amplifier  
to drive the ADC08D500 as many high speed amplifiers will have higher distortion than will the ADC08D500,  
resulting in overall system performance degradation.  
Driving the VBG pin to change the reference voltage. As mentioned in THE REFERENCE VOLTAGE, the  
reference voltage is intended to be fixed to provide one of two different full-scale values (650 mVP-P and 870  
mVP-P). Over driving this pin will not change the full scale value, but can otherwise upset operation.  
Driving the clock input with an excessively high level signal. The ADC clock level should not exceed the  
level described in the Operating Ratings Table or the input offset could change.  
Inadequate clock levels. As described in THE CLOCK INPUTS, insufficient clock levels can result in poor  
performance. Excessive clock levels could result in the introduction of an input offset.  
Using a clock source with excessive jitter, using an excessively long clock signal trace, or having other  
signals coupled to the clock signal trace. This will cause the sampling interval to vary, causing excessive  
output noise and a reduction in SNR performance.  
Failure to provide adequate heat removal. As described in Thermal Management, it is important to provide  
adequate heat removal to ensure device reliability. This can either be done with adequate air flow or the use of a  
simple heat sink built into the board. The backside pad should be grounded for best performance.  
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REVISION HISTORY  
Changes from Revision E (April 2013) to Revision F  
Page  
Changed layout of National Data Sheet to TI format .......................................................................................................... 43  
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PACKAGE OPTION ADDENDUM  
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10-Dec-2020  
PACKAGING INFORMATION  
Orderable Device  
Status Package Type Package Pins Package  
Eco Plan  
Lead finish/  
Ball material  
MSL Peak Temp  
Op Temp (°C)  
Device Marking  
Samples  
Drawing  
Qty  
(1)  
(2)  
(3)  
(4/5)  
(6)  
ADC08D500CIYB/NOPB  
ACTIVE  
HLQFP  
NNB  
128  
60  
RoHS & Green  
SN  
Level-3-260C-168 HR  
-40 to 85  
ADC08D500  
CIYB  
(1) The marketing status values are defined as follows:  
ACTIVE: Product device recommended for new designs.  
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.  
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.  
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.  
OBSOLETE: TI has discontinued the production of the device.  
(2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance  
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may  
reference these types of products as "Pb-Free".  
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.  
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based  
flame retardants must also meet the <=1000ppm threshold requirement.  
(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.  
(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.  
(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation  
of the previous line and the two combined represent the entire Device Marking for that device.  
(6)  
Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two  
lines if the finish value exceeds the maximum column width.  
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information  
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and  
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.  
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.  
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.  
Addendum-Page 1  
PACKAGE MATERIALS INFORMATION  
www.ti.com  
23-Jun-2023  
TRAY  
L - Outer tray length without tabs  
KO -  
Outer  
tray  
height  
W -  
Outer  
tray  
width  
Text  
P1 - Tray unit pocket pitch  
CW - Measurement for tray edge (Y direction) to corner pocket center  
CL - Measurement for tray edge (X direction) to corner pocket center  
Chamfer on Tray corner indicates Pin 1 orientation of packed units.  
*All dimensions are nominal  
Device  
Package Package Pins SPQ Unit array  
Max  
matrix temperature  
(°C)  
L (mm)  
W
K0  
P1  
CL  
CW  
Name  
Type  
(mm) (µm) (mm) (mm) (mm)  
ADC08D500CIYB/NOPB  
NNB  
HLQFP  
128  
60  
5 X 12  
150  
322.6 135.9 7620 25.4  
17.8 17.55  
Pack Materials-Page 1  
MECHANICAL DATA  
NNB0128A  
VNX128A (Rev B)  
www.ti.com  
IMPORTANT NOTICE AND DISCLAIMER  
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DESIGNS), APPLICATION OR OTHER DESIGN ADVICE, WEB TOOLS, SAFETY INFORMATION, AND OTHER RESOURCES “AS IS”  
AND WITH ALL FAULTS, AND DISCLAIMS ALL WARRANTIES, EXPRESS AND IMPLIED, INCLUDING WITHOUT LIMITATION ANY  
IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT OF THIRD  
PARTY INTELLECTUAL PROPERTY RIGHTS.  
These resources are intended for skilled developers designing with TI products. You are solely responsible for (1) selecting the appropriate  
TI products for your application, (2) designing, validating and testing your application, and (3) ensuring your application meets applicable  
standards, and any other safety, security, regulatory or other requirements.  
These resources are subject to change without notice. TI grants you permission to use these resources only for development of an  
application that uses the TI products described in the resource. Other reproduction and display of these resources is prohibited. No license  
is granted to any other TI intellectual property right or to any third party intellectual property right. TI disclaims responsibility for, and you  
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Copyright © 2023, Texas Instruments Incorporated  

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