Integrated dual 10-bit ADC
Single 3 V supply operation
SNR = 57.6 dBc (to Nyquist, AD9216-105)
SFDR = 74 dBc (to Nyquist, AD9216-105)
Low power: 150 mW/ch at 105 MSPS
Differential input with 300 MHz 3 dB bandwidth
Exceptional crosstalk immunity < -80 dB
Offset binary or twos complement data format
Clock duty cycle stabilizer
APPLICATIONS
Ultrasound equipment
IF sampling in communications receivers
3G, radio point-to-point, LMDS, MMDS
Battery-powered instruments
Hand-held scopemeters
Low cost digital oscilloscopes
GENERAL DESCRIPTION
The AD9216 is a dual, 3 V, 10-bit, 105 MSPS analog-to-digital
converter (ADC). It features dual high performance sampleand-hold amplifiers (SHAs) and an integrated voltage reference.
The AD9216 uses a multistage differential pipelined architecture with output error correction logic to provide 10-bit
accuracy and guarantee no missing codes over the full
operating temperature range at up to 105 MSPS data rates.
The wide bandwidth, differential SHA allows for a variety of
user selectable input ranges and offsets, including single-ended
applications. The AD9216 is suitable for various applications,
including multiplexed systems that switch full-scale voltage
levels in successive channels and for sampling inputs at
frequencies well beyond the Nyquist rate.
Dual A/D Converter
AD9216
FUNCTIONAL BLOCK DIAGRAM
AVDD AGND
VIN+_A
VIN–_A
REFT_A
REFB_A
VREF
SENSE
AGND
REFT_B
REFB_B
VIN+_B
VIN–_B
SHA
0.5V
SHA
AD9216
ADC
ADC
DRVDD
Figure 1.
10
OUTPUT
BUFFERS
CLOCK
DUTY CYCLE
STABILIZER
CONTROL
10
OUTPUT
BUFFERS
DRGND
Fabricated on an advanced CMOS process, the AD9216 is available in a space saving, Pb-free, 64-lead LFCSP (9 mm × 9 mm) and
is specified over the industrial temperature range (−40°C to
+85°C).
PRODUCT HIGHLIGHTS
1. Pin compatible with AD9238, dual 12-bit 20 MSPS/40 MSPS/
2. 105 MSPS capability allows for demanding, high frequency
applications.
MUX/
MODE
MUX/
10
10
D9_A–D0_A
OEB_A
MUX_SELECT
CLK_A
CLK_B
DCS
SHARED_REF
PWDN_A
PWDN_B
DFS
D9_B–D0_B
OEB_B
04775-001
Dual single-ended clock inputs are used to control all internal
conversion cycles. A duty cycle stabilizer is available on the
AD9216 and can compensate for wide variations in the clock
duty cycle, allowing the converters to maintain excellent
performance. The digital output data is presented in either
straight binary or twos complement format.
Rev. A
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
3. Low power consumption: AD9216–105: 105 MSPS = 300 mW.
4. The patented SHA input maintains excellent performance for
input frequencies up to 200 MHz and can be configured for
single-ended or differential operation.
5. Typical channel crosstalk of < −80 dB at f
up to 70 MHz.
IN
6. The clock duty cycle stabilizer maintains performance over a
AVDD = 3.0 V, DRVDD = 2.5 V, maximum sample rate, CLK_A = CLK_B; AIN = −0.5 dBFS differential input, 1.0 V internal reference,
to T
T
MIN
Table 1.
Parameter
RESOLUTION Full VI 10 10 10 Bits
ACCURACY
No Missing Codes Full VI Guaranteed Guaranteed Guaranteed
Offset Error Full VI -1.9 ±0.3 +1.9 -1.9 ±0.3 +1.9 −2.2 ±0.3 +2.2 % FSR
Gain Error
Differential Nonlinearity (DNL)
25°C I -0.9 ±0.3 +0.9 -0.9 ±0.4 +0.9 −1.0 ±0.5 +1.0 LSB
Integral Nonlinearity (INL)2 Full IV -1.4 ±0.5 +1.4 -1.6 ±0.5 +1.6 −2.5 ±1.0 +2.5 LSB
25°C I -1.0 ±0.5 +1.0 -1.1 ±0.5 +1.1 −1.5 ±1.0 +1.5 LSB
TEMPERATURE DRIFT
Offset Error Full V ±10 ±10 ±10 µV/°C
Gain Error1 Full V ±75 ±75 ±75 ppm/°C
Reference Voltage Full V ±15 ±15 ±15 ppm/°C
INTERNAL VOLTAGE REFERENCE
Output Voltage Error Full VI ±2 ±35 ±2 ±35 ±2 ±35 mV
Load Regulation @ 1.0 mA 25°C V 1.0 1.0 1.0 mV
INPUT REFERRED NOISE
Input Span = 2.0 V 25°C V 0.5 0.5 0.5 LSB
ANALOG INPUT
Input Span, VREF = 1.0 V Full IV 2 2 2 V p-p
Input Capacitance
REFERENCE INPUT RESISTANCE 25°C V 7 7 7 kΩ
POWER SUPPLIES
Supply Voltages
Supply Current
PSRR 25°C V ±0.1 ±0.1 ±0.1 % FSR
POWER CONSUMPTION
P
AVDD
P
DRVDD
Standby Power
MATCHING CHARACTERISTICS
Offset Matching Error
Gain Matching Error (Shared Reference
Mode)
Gain Matching Error (Nonshared
Reference Mode)
1
Gain error and gain temperature coefficient are based on the ADC only (with a fixed 1.0 V external reference).
2
Measured with low frequency ramp at maximum clock rate.
3
Input capacitance refers to the effective capacitance between one differential input pin and AVSS. Refer to Figure for the equivalent analog input structure. 37
4
Measured with low frequency analog input at maximum clock rate with approximately 5 pF loading on each output bit.
5
Standby power is measured with the CLK_A and CLK_B pins inactive (that is, set to AVDD or AGND).
6
Both shared reference mode and nonshared reference mode.
, DCS enabled, unless otherwise noted.
MAX
TempTestAD9216BCPZ-65AD9216BCPZ-80AD9216BCPZ-105
1
2
3
25°C VI -1.6 ±0.4 +1.6 -1.6 ±0.4 +1.6 −1.6 ±0.4 +1.6 % FSR
Full IV -1.0 ±0.3 +1.0 -1.0 ±0.4 +1.0 −1.0 ±0.5 +1.0 LSB
25°C V 2 2 2 pF
Level Min Typ Max Min Typ Max Min Typ Max Unit
rms
AVDD Full IV 2.7 3.0 3.3 2.7 3.0 3.3 2.7 3.0 3.3 V
DRVDD Full IV 2.25 2.5 3.3 2.25 2.5 3.3 2.25 2.5 3.3 V
AVDD = 3.0 V, DRVDD = 2.5 V, maximum sample rate, CLK_A = CLK_B; AIN = −0.5 dBFS differential input, 1.0 V internal reference,
to T
T
MIN
Table 2.
ParameterTempTest
SIGNAL-TO-NOISE RATIO (SNR)
f
INPUT
f
INPUT
25°C I 57.2 58.4 56.4 58.5 56.4 57.6 dB
f
INPUT
f
INPUT
SIGNAL-TO-NOISE AND DISTORTION
RATIO (SINAD)
f
INPUT
f
INPUT
25°C I 57.0 58.3 56.2 58.0 56.1 57.4 dB
f
INPUT
f
INPUT
EFFECTIVE NUMBER OF BITS (ENOB)
f
INPUT
f
INPUT
25°C I 9.2 9.4 9.0 9.3 9.1 9.3 Bits
f
INPUT
f
INPUT
WORST HARMONIC (SECOND OR
THIRD)
f
INPUT
f
INPUT
25°C I −79.5 -67.8 −77.0 -67.2 −74.0 −66.5 dBc
f
INPUT
f
INPUT
WORST OTHER (EXCLUDING
SECOND OR THIRD)
f
INPUT
f
INPUT
25°C I −80.5 -68.7 −78.0 -67.8 −75.0 −67.5 dBc
f
INPUT
f
INPUT
SPURIOUS-FREE DYNAMIC RANGE
(SFDR)
f
INPUT
f
INPUT
25°C I 67.8 79.5 67.2 77.0 66.5 74.0 dBc
f
INPUT
f
INPUT
TWO-TONE SFDR (AIN = −7 dBFS)
f
IN1
f
IN1
ANALOG BANDWIDTH 25°C V 300 300 300 MHz
CROSSTALK 25°C V −80.0 −80.0 −80.0 dB
1
Nyquist = approximately 32 MHz, 40MHz, 50MHz for the −65, −80, and −105 grades respectively
, DCS enabled, unless otherwise noted.
MAX
AD9216BCPZ-65 AD9216BCPZ-80 AD9216BCPZ-105
Min Typ Max Min Typ Max Min Typ Max Unit
Level
= 2.4 MHz 25°C V 58.6 58.5 58.0 dB
= Nyquist
1
Full IV 56.6 58.4 55.9 58.1 54.8 57.6 dB
= 69 MHz 25°C V 58.0 58.0 57.4 dB
= 100 MHz 25°C V 57.5 57.5 57.3 dB
= 2.4 MHz 25°C V 58.5 58.2 57.8 dB
= Nyquist1 Full IV 56.4 58.3 55.4 58.0 53.4 57.4 dB
= 69 MHz 25°C V 57.5 57.5 56.8 dB
= 100 MHz 25°C V 57.0 57.0 56.7 dB
= 2.4 MHz 25°C V 9.4 9.4 9.3 Bits
= Nyquist1 Full IV 9.1 9.4 8.9 9.3 8.6 9.3 Bits
= 69 MHz 25°C V 9.3 9.3 9.2 Bits
= 100 MHz 25°C V 9.3 9.3 9.2 Bits
= 2.4 MHz Full IV −82.0 −81.0 −76.0 dBc
= Nyquist1 Full IV −79.5 -65.1 −77.0 -64.1 −74.0 −60.0 dBc
= 69 MHz 25°C V −79.0 −76.5 −74.0 dBc
= 100 MHz 25°C V −78.5 −76.0 −74.0 dBc
= 2.4 MHz Full IV −82.5 −81.5 −76.5 dBc
= Nyquist1 Full IV −80.5 -65.8 −78.0 -64.5 −75.0 −62.0 dBc
= 69 MHz 25°C V −80.0 −77.5 −75.0 dBc
= 100 MHz 25°C V −79.5 −77.0 −75.0 dBc
= 2.4 MHz Full IV 82.0 81.0 76.0 dBc
= Nyquist1 Full IV 65.1 79.5 64.1 77.0 60.0 74.0 dBc
= 69 MHz 25°C V 79.0 76.5 74.0 dBc
= 100 MHz 25°C V 78.5 76.0 74.0 dBc
= 69.1 MHz, f
= 100.1 MHz, f
= 70.1 MHz 25°C V 71.0 70.0 70.0 dBc
IN2
= 101.1 MHz 25°C V 70.0 69.0 69.0 dBc
IN2
Rev. A | Page 4 of 40
AD9216
LOGIC SPECIFICATIONS
AVDD = 3.0 V, DRVDD = 2.5 V, maximum sample rate, CLK_A = CLK_B; AIN = −0.5 dBFS differential input, 1.0 V internal reference,
to T
T
MIN
Table 3.
ParameterTempTest
LOGIC INPUTS
High Level Input
Voltage
Low Level Input
Voltage
High Level Input
Current
Low Level Input
Current
Input Capacitance Full IV 2 2 2 pF
LOGIC OUTPUTS
DRVDD = 2.5 V
1
Output voltage levels measured with 5 pF load on each output.
, DCS enabled, unless otherwise noted.
MAX
Full IV 2.0 2.0 2.0 V
Full IV 0.8 0.8 0.8 V
Full IV −10 +10 −10 +10 −10 +10 µA
Full IV −10 +10 −10 +10 −10 +10 µA
1
High Level Output
Full IV 2.45 2.45 2.45 V
Voltage
Low Level Output
Full IV 0.05 0.05 0.05 V
Voltage
AD9216BCPZ-65 AD9216BCPZ-80 AD9216BCPZ-105
Min Typ Max Min Typ Max Min Typ Max Unit
Level
Rev. A | Page 5 of 40
AD9216
SWITCHING SPECIFICATIONS
AVDD = 3.0 V, DRVDD = 2.5 V, maximum sample rate, CLK_A = CLK_B; AIN = −0.5 dBFS differential input, 1.0 V internal reference,
to T
T
MIN
Table 4.
Parameter Temp Test Level Min Typ Max Min Typ Max Min Typ Max Unit
SWITCHING PERFORMANCE
Maximum Conversion Rate Full VI 65 80 105 MSPS
Minimum Conversion Rate Full IV 10 10 10 MSPS
OUTPUT PARAMETERS
Output Propagation Delay2 (tPD) 25°C I 4.5 6.4 4.5 6.4 4.5 6.4 nS
Valid Time3 (tV) 25°C I 2.0 2.0 2.0
Output Rise Time (10% to 90%) 25°C V 1.0 1.0 1.0 nS
Output Fall Time (10% to 90%) 25°C V 1.0 1.0 1.0 nS
Output Enable Time
Output Disable Time4 Full IV 1 1 1 Cycle
Pipeline Delay (Latency) Full IV 6 6 6 Cycle
APERTURE
Aperture Delay (tA) 25°C V 1.5 1.5 1.5 nS
Aperture Uncertainty (tJ) 25°C V 0.5 0.5 0.5 pS
Wake-Up Time
OUT-OF-RANGE RECOVERY TIME 25°C V 1 1 1 Cycle
1
C
LOAD
2
Output delay is measured from clock 50% transition to data 50% transition.
3
Valid time is approximately equal to the minimum output propagation delay.
4
Output enable time is OEB_A, OEB_B falling to respective channel outputs coming out of high impedance. Output disable time is OEB_A, OEB_B rising to respective
channel outputs going into high impedance.
5
Wake-up time is dependent on value of decoupling capacitors; typical values shown for 0.1 µF and 10 µF capacitors on REFT and REFB.
, DCS enabled, unless otherwise noted.
MAX
AD9216BCPZ-65AD9216BCPZ-80AD9216BCPZ-105
CLK Period Full VI 15.4 12.5 9.5 nS
CLK Pulse Width High Full VI 4.6 4.4 3.8 nS
CLK Pulse Width Low Full VI 4.6 4.4 3.8 nS
1
4
5
equals 5 pF maximum for all output switching parameters.
Junction Temperature 150°C
Lead Temperature (10 sec) 300°C
Storage Temperature
1
Typical thermal impedances (64-lead LFCSP); θ
measurements were taken on a 4-layer board (with thermal via array) in still
air, in accordance with EIA/JESD51-7.
1
AGND
AGND
AGND
= 26.4°C/W. These
JA
−0.3 V to
+3.9 V
−0.3 V to
+3.9 V
−0.3 V to
+0.3 V
−0.3 V to
+3.9 V
−0.3 V to
DRVDD +
0.3 V
−0.3 V to
AVDD +
0.3 V
−0.3 V to
AVDD +
0.3 V
−0.3 V to
AVDD +
0.3 V
−40°C to
+85°C
−65°C to
+150°C
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only and functional operation of the device at these or
any other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
EXPLANATION OF TEST LEVELS
Table 6.
Test Level Description
I 100% production tested.
II
III Sample tested only.
IV
V Parameter is a typical value only.
VI
100% production tested at 25°C and sample
tested at specified temperatures.
Parameter is guaranteed by design and
characterization testing.
100% production tested at 25°C; guaranteed by
design and characterization testing for industrial
temperature range; 100% production tested at
temperature extremes for military devices.
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
Rev. A | Page 8 of 40
AD9216
A
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
AVDD
CLK_A
SHARED_REF
MUX_SELECT
PDWN_A
OEB_A
DNC
D9_A (MSB)
D8_A
D7_A
D6_A
DRGND
DRVDD
D5_A
D4_A
646362616059585756555453525150
D3_A
49
AGND
1
VIN+_A
2
VIN–_A
3
AGND
4
AVDD
5
REFT_A
6
REFB_
7
8
VREF
9
SENSE
10
REFB_B
11
REFT_B
12
AVDD
13
AGND
14
VIN–_B
15
VIN+_B
16
AGND
DNC =
DO NOT CONNECT
PIN 1
INDICATOR
AD9216
TOP VIEW
(Not to Scale)
171819202122232425262728293031
DFS
DCS
DNC
DNC
DNC
DNC
D0_B (LSB)
DRVDD
DRGND
D1_B
AVDD
CLK_B
OEB_B
PDWN_B
D2_B
32
D3_B
48
D2_A
47
D1_A
46
D0_A (LSB)
45
DNC
44
DNC
43
DNC
42
DNC
41
DRVDD
40
DRGND
39
DNC
38
D9_B (MSB)
37
D8_B
36
D7_B
35
D6_B
34
D5_B
33
D4_B
04775-003
Figure 3. Pin Configuration
Table 7. Pin Function Descriptions
Pin No. Mnemonic Description
1, 4, 13, 16 AGND
1
Analog Ground.
2 VIN+_A Analog Input Pin (+) for Channel A.
3 VIN−_A Analog Input Pin (−) for Channel A.
5, 12, 17, 64 AVDD Analog Power Supply.
6 REFT_A Differential Reference (+) for Channel A.
7 REFB_A Differential Reference (−) for Channel A.
8 VREF Voltage Reference Input/Output.
9 SENSE Reference Mode Selection.
10 REFB_B Differential Reference (−) for Channel B.
11 REFT_B Differential Reference (+) for Channel B.
14 VIN−_B Analog Input Pin (−) for Channel B.
15 VIN+_B Analog Input Pin (+) for Channel B.
18 CLK_B Clock Input Pin for Channel B.
19 DCS Duty Cycle Stabilizer (DCS) Mode Pin (Active High).
20 DFS Data Output Format Select Pin. Low for offset binary; high for twos complement.
21 PDWN_B Power-Down Function Selection for Channel B.
Logic 0 enables Channel B.
Logic 1 powers down Channel B. (Outputs static, not High-Z.)
22 OEB_B Output Enable for Channel B.
Logic 0 enables Data Bus B.
Logic 1 sets outputs to High-Z.
Digital Output Driver Supply. Must be decoupled to DRGND with a minimum 0.1 µF capacitor.
Recommended decoupling is 0.1 µF capacitor in parallel with 10 µF.
Rev. A | Page 9 of 40
AD9216
Pin No. Mnemonic Description
46 to 51,
54 to 57
D0_A (LSB) to
D9_A (MSB)
59 OEB_A Output Enable for Channel A.
60 PDWN_A Power-Down Function Selection for Channel A.
61 MUX_SELECT Data Multiplexed Mode. (See Data Format section for how to enable.)
62 SHARED_REF Shared Reference Control Bit. Low for independent reference mode; high for shared reference mode.
63 CLK_A Clock Input Pin for Channel A.
1
It is recommended that all ground pins (AGND and DRGND) be tied to a common ground plane.
Channel A Data Output Bits.
Logic 0 enables Data Bus A.
Logic 1 sets outputs to High-Z.
Logic 0 enables Channel A.
Logic 1 powers down Channel A. (Outputs static, not High-Z.)
Rev. A | Page 10 of 40
AD9216
TERMINOLOGY
Analog Bandwidth
The analog input frequency at which the spectral power of the
fundamental frequency (as determined by the FFT analysis) is
reduced by 3 dB.
Aperture Delay
The delay between the 50% point of the rising edge of the
encode command and the instant the analog input is sampled.
Aperture Uncertainty (Jitter)
The sample-to-sample variation in aperture delay.
Clock Pulse Width/Duty Cycle
Pulse-width high is the minimum amount of time that the
clock pulse should be left in a Logic 1 state to achieve rated
performance; pulse-width low is the minimum time clock pulse
should be left in a low state. At a given clock rate, these
specifications define an acceptable clock duty cycle.
Crosstalk
Coupling onto one channel being driven by a low level (−40
dBFS) signal when the adjacent interfering channel is driven by
a full-scale signal.
Differential Analog Input Resistance, Differential Analog
Input Capacitance, and Differential Analog Input
Impedance
The real and complex impedances measured at each analog
input port. The resistance is measured statically and the
capacitance and differential input impedances are measured
with a network analyzer.
Differential Analog Input Voltage Range
The peak-to-peak differential voltage that must be applied to
the converter to generate a full-scale response. Peak differential
voltage is computed by observing the voltage on a single pin
and subtracting the voltage from the other pin, which is 180°
out of phase. Peak-to-peak differential is computed by rotating
the inputs phase 180° and by taking the peak measurement
again. The difference is then computed between both peak
measurements.
Differential Nonlinearity
The deviation of any code width from an ideal 1 LSB step.
Effective Number of Bits (ENOB)
The ENOB is calculated from the measured SINAD based on
the equation (assuming full-scale input)
SINAD
ENOB
=
MEASURED
6.02
dB1.76−
Full-Scale Input Power
Expressed in dBm and computed using the following equation.
2
⎛
V
⎜
Power
=
SCALEFULL
⎜
log10
⎜
⎜
⎜
⎝
SCALEFULL
Z
INPUT
0.001
rms
⎞
⎟
⎟
⎟
⎟
⎟
⎠
Gain Error
The difference between the measured and ideal full-scale input
voltage range of the ADC.
Harmonic Distortion, Second
The ratio of the rms signal amplitude to the rms value of the
second harmonic component, reported in dBc.
Harmonic Distortion, Third
The ratio of the rms signal amplitude to the rms value of the
third harmonic component, reported in dBc.
Integral Nonlinearity
The deviation of the transfer function from a reference line
measured in fractions of 1 LSB using a best straight line
determined by a least square curve fit.
Minimum Conversion Rate
The encode rate at which the SNR of the lowest analog signal
frequency drops by no more than 3 dB below the guaranteed limit.
Maximum Conversion Rate
The encode rate at which parametric testing is performed.
Output Propagation Delay
The delay between a 50% crossing of the CLK rising edge and
the time when all output data bits are within valid logic levels.
Rev. A | Page 11 of 40
AD9216
Noise (for Any Range within the ADC)
This value includes both thermal and quantization noise.
noise
ZV
⎛
××=
10.0010
⎜
⎜
⎝
−−
10
⎞
dBFSdBcdBm
⎟
⎟
⎠
SignalSNRFS
where:
Z is the input impedance.
FS is the full scale of the device for the frequency in question.
SNR is the value for the particular input level.
Signal
is the signal level within the ADC reported in dB below
full scale.
Power Supply Rejection Ratio
The specification shows the maximum change in full scale
from the value with the supply at the minimum limit to the
value with the supply at its maximum limit.
Signal-to-Noise and Distortion (SINAD)
The ratio of the rms signal amplitude (set 1 dB below full scale)
to the rms value of the sum of all other spectral components,
including harmonics, but excluding dc.
Two-Tone Intermodulation Distortion Rejection
The ratio of the rms value of either input tone to the rms value
of the worst third-order intermodulation product, in dBc.
Two-Tone SFDR
The ratio of the rms value of either input tone to the rms value
of the peak spurious component. The peak spurious
component may or may not be an IMD product. It also may be
reported in dBc (that is, degrades as signal level is lowered) or
in dBFS (that is, always relates back to converter full scale).
Worst Other Spur
The ratio of the rms signal amplitude to the rms value of the
worst spurious component (excluding the second and third
harmonic), reported in dBc.
Transi ent Res p onse T i m e
The time it takes for the ADC to reacquire the analog input
after a transient from 10% above negative full scale to 10%
below positive full scale.
Out-of-Range Recovery Time
The time it takes for the ADC to reacquire the analog input
after a transient from 10% above positive full scale to 10% above
negative full scale, or from 10% below negative full scale to 10%
below positive full scale.
Signal-to-Noise Ratio (without Harmonics)
The ratio of the rms signal amplitude (set at 1 dB below
full scale) to the rms value of the sum of all other spectral
components, excluding the first seven harmonics and dc.
Spurious-Free Dynamic Range (SFDR)
The ratio of the rms signal amplitude to the rms value of
the peak spurious spectral component. The peak spurious
component may or may not be a harmonic. It also may be
reported in dBc (that is, degrades as signal level is lowered)
or dBFS (that is, always related back to converter full scale).
Rev. A | Page 12 of 40
AD9216
TYPICAL PERFORMANCE CHARACTERISTICS
AVDD = 3.0 V, DRVDD = 2.5 V, T = 25°C, AIN differential drive, internal reference, DCS on, unless otherwise noted.
Figure 36. Typical Propagation Delay vs. Temperature ( All Speed Grades)
–1.0
–1.5
–2.0
02004006008001000
Figure 35. Typical INL Plot, A
CODE
= 10.3 MHz at −0.5 dBFS, 105 MSPS
IN
(−105 Grade)
04775-036
Rev. A | Page 18 of 40
AD9216
EQUIVALENT CIRCUITS
AVDD
AVDD
VIN+_A, VIN–_A,
VIN+_B, VIN–_B
CLK_A, CLK_B
DCS, DFS,
MUX_SELECT,
SHARED_REF
Figure 37. Equivalent Analog Input
AVDD
Figure 38. Equivalent Clock, Digital Inputs Circuit
04775-004
04775-005
PDWN
30kΩ
04775-006
Figure 39. Power-Down Input
DRVDD
04775-007
Figure 40. Digital Outputs
Rev. A | Page 19 of 40
AD9216
THEORY OF OPERATION
The AD9216 consists of two high performance ADCs that are
based on the AD9215 converter core. The dual ADC paths are
independent, except for a shared internal band gap reference
source, VREF. Each of the ADC paths consists of a proprietary
front end SHA followed by a pipelined, switched-capacitor ADC.
The pipelined ADC is divided into three sections, consisting of
a sample-and-hold amplifier, followed by seven 1.5-bit stages,
and a final 3-bit flash. Each stage provides sufficient overlap to
correct for flash errors in the preceding stages. The quantized
outputs from each stage are combined through the digital
correction logic block into a final 10-bit result. The pipelined
architecture permits the first stage to operate on a new input
sample, while the remaining stages operate on preceding
samples. Sampling occurs on the rising edge of the respective clock.
Each stage of the pipeline, excluding the last, consists of a low
resolution flash ADC and a residual multiplier to drive the next
stage of the pipeline. The residual multiplier uses the flash
ADC output to control a switched capacitor digital-to-analog
converter (DAC) of the same resolution. The DAC output is
subtracted from the stage’s input signal and the residual is
amplified (multiplied) to drive the next pipeline stage. The
residual multiplier stage is also called a multiplying DAC
(MDAC). One bit of redundancy is used in each one of the
stages to facilitate digital correction of flash errors. The last
stage simply consists of a flash ADC.
The input stage contains a differential SHA that can be configured as ac- or dc-coupled in differential or single-ended modes.
The output-staging block aligns the data, carries out the error
correction, and passes the data to the output buffers. The output
buffers are powered from a separate supply, allowing
adjustment of the output voltage swing.
ANALOG INPUT
The analog input to the AD9216 is a differential switchedcapacitor SHA that has been designed for optimum performance while processing a differential input signal. The SHA
input accepts inputs over a wide common-mode range. An
input common-mode voltage of midsupply is recommended
to maintain optimal performance.
This passive network creates a low-pass filter at the ADC’s
input; therefore, the precise values are dependant on the
application. In IF under-sampling applications, any shunt
capacitors should be removed. In combination with the driving source impedance, they would limit the input bandwidth.
For best dynamic performance, the source impedances driving
VIN+ and VIN− should be matched, so the common-mode
settling errors are symmetrical. These errors are reduced by the
common-mode rejection of the ADC.
H
VIN+
VIN
T
C
PAR
T
–
C
PAR
Figure 41. Switched-Capacitor Input
0.5pF
0.5pF
T
T
H
04775-008
An internal differential reference buffer creates positive and
negative reference voltages, REFT and REFB, respectively, that
define the span of the ADC core. The output common-mode
of the reference buffer is set to midsupply, and the REFT and
REFB voltages and span are defined as:
REFT = 1/2 (AV D D + VREF)
REFB = 1/2 (AV D D − VREF)
Span = 2 × (REFT − REFB) = 2 × VREF
It can be seen from the equations above that the REFT and
REFB voltages are symmetrical about the midsupply voltage and,
by definition, the input span is twice the value of the VREF voltage.
The SHA may be driven from a source that keeps the signal
peaks within the allowable range for the selected reference
voltage. The minimum and maximum common-mode input
levels are defined as
The SHA input is a differential switched-capacitor circuit.
In Figure 41, the clock signal alternatively switches the SHA
between sample mode and hold mode. When the SHA is
switched into sample mode, the signal source must be capable
of charging the sample capacitors and settling within one-half
of a clock cycle. A small resistor in series with each input can
help reduce the peak transient current required from the output
stage of the driving source. Also, a small shunt capacitor can be
placed across the inputs to provide dynamic charging currents.
Rev. A | Page 20 of 40
VCM
VCM
= VREF/2
MIN
= (AV D D + VREF)/2
MAX
The minimum common-mode input level allows the AD9216
to accommodate ground-referenced inputs. Although optimum
performance is achieved with a differential input, a single-ended
source may be driven into VIN+ or VIN−. In this configuration,
one input accepts the signal, while the opposite input should be
set to midscale by connecting it to an appropriate reference.
AD9216
2
For example, a 2 V p-p signal may be applied to VIN+, while a
1 V reference is applied to VIN−. The AD9216 then accepts an
input signal varying between 2 V and 0 V. In the single-ended
configuration, distortion performance may degrade significantly as compared to the differential case. However, the effect
is less noticeable at lower input frequencies.
85
80
75
70
65
dB
60
55
50
45
40
0.250.751.251.752.252.75
ANALOG INPUT COMMON-MODE VOLTAGE (V)
2V p-p SFDR
2V p-p SNR
04775-009
Figure 42. Input Common-Mode Voltage Sensitivity
Differential Input Configurations
As previously detailed, optimum performance is achieved while
driving the AD9216 in a differential input configuration. For
baseband applications, the AD8138 differential driver provides
excellent performance and a flexible interface to the ADC. The
output common-mode voltage of the AD8138 is easily set to
AVDD/2, and the driver can be configured in a Sallen-Key filter
topology to provide band limiting of the input signal.
At input frequencies in the second Nyquist zone and above, the
performance of most amplifiers is not adequate to achieve the
true performance of the AD9216. This is especially true in IF
under-sampling applications where frequencies in the 70 MHz
to 200 MHz range are being sampled. For these applications,
differential transformer coupling is the recommended input
configuration, as shown in Figure 43.
AVDD
VIN_A
AD9216
VIN_B
AGND
V p-p
49.9Ω
50Ω
10pF
50Ω
10pF
1kΩ
For dc-coupled applications, the AD8138, AD8139, or
AD8351 can serve as a convenient ADC driver, depending on
requirements. Figure 44 shows an example with the AD8138.
The AD9216 PCB has an optional AD8139 on board, as shown
in Figure 53. Note the AD8351 typically yields better performance for frequencies greater than 30 MHz to 40 MHz.
49.9Ω
1kΩ
1kΩ
0.1µF
Figure 44. Driving the ADC with the AD8138
SENSE = GROUND
VIN+
FULL
SCALE/2
AVDD/2AVDD/2
VIN–
DIGITAL OUT = ALL ONESDIGITAL OUT = ALL ZEROES
Figure 45. Analog Input Full Scale (Full Scale = 2 V)
499Ω
523Ω
499Ω
AD8138
499Ω
33Ω
33Ω
20pF
AVDD
VIN+
AD9216
VIN–
AGND
04775-011
04775-012
Single-Ended Input Configuration
A single-ended input may provide adequate performance in
cost-sensitive applications. In this configuration, there is a
degradation in SFDR and distortion performance due to the
large input common-mode swing. However, if the source
impedances on each input are matched, there should be little
effect on SNR performance.
0.1µF
1kΩ
04775-010
Figure 43. Differential Transformer Coupling
The signal characteristics must be considered when selecting a
transformer. Most RF transformers saturate at frequencies
below a few MHz, and excessive signal power can also cause
core saturation, which leads to distortion.
Rev. A | Page 21 of 40
AD9216
CLOCK INPUT AND CONSIDERATIONS
Typical high speed ADCs use both clock edges to generate
a variety of internal timing signals and, as a result, may be
sensitive to clock duty cycle. Commonly, a 5% tolerance is
required on the clock duty cycle to maintain dynamic
performance characteristics.
The AD9216 provides separate clock inputs for each channel.
The optimum performance is achieved with the clocks operated
at the same frequency and phase. Clocking the channels asynchronously may degrade performance significantly. In some
applications, it is desirable to skew the clock timing of adjacent
channels. The AD9216’s separate clock inputs allow for clock
timing skew (typically ±1 ns) between the channels without
significant performance degradation.
POWER DISSIPATION AND STANDBY MODE
The power dissipated by the AD9216 is proportional to its
sampling rates. The digital (DRVDD) power dissipation is
determined primarily by the strength of the digital drivers
and the load on each output bit. The digital drive current can
be calculated by
I
= V
DRVDD
where
N is the number of bits changing, and C
load on the digital pins that changed.
The analog circuitry is optimally biased, so each speed grade
provides excellent performance while affording reduced power
consumption. Each speed grade dissipates a baseline power at
low sample rates that increases with clock frequency.
DRVDD
× C
LOAD
× f
CLOCK
× N
is the average
LOAD
The AD9216 contains two clock duty cycle stabilizers, one for
each converter, that retime the nonsampling edge, providing an
internal clock with a nominal 50% duty cycle. Faster input clock
rates, where it becomes difficult to maintain 50% duty cycles,
can benefit from using DCS, as a wide range of input clock duty
cycles can be accommodated. Maintaining a 50% duty cycle
clock is particularly important in high speed applications, when
proper track-and-hold times for the converter are required to
maintain high performance. The DCS can be enabled by tying
the DCS pin high.
The duty cycle stabilizer uses a delay-locked loop to create the
nonsampling edge. As a result, any changes to the sampling
frequency require approximately 2 µs to 3 µs to allow the DLL
to acquire and settle to the new rate.
High speed, high resolution ADCs are sensitive to the quality of
the clock input. The degradation in SNR at a given full-scale
input frequency (f
) due only to aperture jitter (tJ) can be
INPUT
calculated by
SNR degradation = 2 × log 10[1/2 × p × f
In the equation, the rms aperture jitter,
t
, represents the root-
J
INPUT
× tJ]
sum square of all jitter sources, which includes the clock input,
analog input signal, and ADC aperture jitter specification. Undersampling applications are particularly sensitive to jitter.
For optimal performance, especially in cases where aperture jitter may affect the dynamic range of the AD9216, it
is important to minimize input clock jitter. The clock input
circuitry should use stable references; for example, use analog
power and ground planes to generate the valid high and low
digital levels for the AD9216 clock input. Power supplies for
clock drivers should be separated from the ADC output driver
supplies to avoid modulating the clock signal with digital noise.
Low jitter, crystal-controlled oscillators make the best clock
sources. If the clock is generated from another type of source
(by gating, dividing, or other methods), it should be retimed by
the original clock at the last step.
Either channel of the AD9216 can be placed into standby mode
independently by asserting the PWDN_A or PDWN_B pins.
Time to go into or come out of standby mode is 5 cycles maximum when only one channel is being powered down. When both
channels are powered down, VREF goes to ground, resulting in a
wake-up time of ~7 ms dependent on decoupling capacitor
values.
It is recommended that the input clock(s) and analog input(s)
remain static during either independent or total standby, which
results in a typical power consumption of 3 mW for the ADC.
If the clock inputs remain active while in total standby mode,
typical power dissipation of 10 mW results.
The minimum standby power is achieved when both channels
are placed into full power-down mode (PDWN_A = PDWN_B
= HI). Under this condition, the internal references are powered
down. When either or both of the channel paths are enabled
after a power-down, the wake-up time is directly related to the
recharging of the REFT and REFB decoupling capacitors and to
the duration of the power-down.
A single channel can be powered down for moderate power
savings. The powered-down channel shuts down internal
circuits, but both the reference buffers and shared reference
remain powered on. Because the buffer and voltage reference
remain powered on, the wake-up time is reduced to several
clock cycles.
DIGITAL OUTPUTS
The AD9216 output drivers can interface directly with 3 V
logic families. Applications requiring the ADC to drive large
capacitive loads or large fanouts may require external buffers
or latches because large drive currents tend to cause current
glitches on the supplies that may affect converter performance.
The data format can be selected for either offset binary or twos
complement. This is discussed in the Data Format section.
The AD9216 provides latched data outputs with a pipeline delay
of six clock cycles. Data outputs are available one propagation
delay (t
Figure 2 for a detailed timing diagram.
The length of the output data lines and loads placed on them
should be minimized to reduce transients within the AD9216.
These transients can detract from the converter’s dynamic
performance. The lowest conversion rate of the AD9216 is
10 MSPS. At clock rates below 10 MSPS, dynamic performance may degrade.
) after the rising edge of the clock signal. Refer to
PD
DATA FORMAT
The AD9216 data output format can be configured for either
twos complement or offset binary. This is controlled by the
data format select pin (DFS). Connecting DFS to AGND
produces offset binary output data. Conversely, connecting
DFS to AVDD formats the output data as twos complement.
The output data from the dual ADCs can be multiplexed onto a
single, 10-bit output bus. The multiplexing is accomplished by
toggling the MUX_SELECT bit, which directs channel data to
the same or opposite channel data port. When MUX_SELECT
is logic high, the Channel A data is directed to the Channel A
output bus, and the Channel B data is directed to the Channel B
output bus. When MUX_SELECT is logic low, the channel
data is reversed; that is, the Channel A data is directed to the
Channel B output bus, and the Channel B data is directed to
the Channel A output bus. By toggling the MUX_SELECT bit,
multiplexed data is available on either of the output data ports.
If the ADCs are run with synchronized timing, this same clock
can be applied to the MUX_SELECT pin. Any skew between
CLK_A, CLK_B, and MUX_SELECT can degrade ac performance. It is recommended to keep the clock skew < 100 pHs.
After the MUX_SELECT rising edge, either data port has
the data for its respective channel; after the falling edge, the
alternate channel’s data is placed on the bus. Typically, the
other unused bus is disabled by setting the appropriate OEB
high to reduce power consumption and noise. Figure 46 shows
an example of multiplex mode. When multiplexing data, the
data rate is two times the sample rate. Note that both channels
must remain active in this mode and that each channel’s powerdown pin must remain low.
A
A
–1
B
–1
0
B
0
B
–7
Figure 46. Example of Multiplexed Data Format Using the Channel A Output and the Same Clock Tied to CLK_A, CLK_B, and MUX_SELECT
A
1
B
1
A
B
–6
–6
A
2
B
2
A
B–5A–4B–4A
–5
A
A
3
B
3
A
4
B
4
B
–3
–3
A
5
B
5
A
B
–2
–2
A–1B
A
6
B
6
A0B0A1B
–1
7
B
7
A
B
1
8
8
ANALOG INPUT
ADC A
ANALOG INPUT
ADC B
CLK_A = CLK_B =
MUX_SELECT
D0_A
–D11_A
04775-013
Rev. A | Page 23 of 40
AD9216
VOLTAGE REFERENCE
A stable and accurate 0.5 V voltage reference is built into
the AD9216. The input range can be adjusted by varying the
reference voltage applied to the AD9216, using either the internal reference with different external resistor configurations or
an externally applied reference voltage. The input span of the
ADC tracks reference voltage changes linearly.
Internal Reference Connection
A comparator within the AD9216 detects the potential at the
SENSE pin and configures the reference into three possible
states, which are summarized in Table 9. If SENSE is grounded,
the reference amplifier switch is connected to the internal resistor
divider (see Figure 47), setting VREF to 1 V. If a resistor divider
is connected, as shown in Figure 48, the switch is again set to the
SENSE pin. This puts the reference amplifier in a noninverting
mode with the VREF output defined as
VREF = 0.5 × (1 + R2/R1)
Table 9. Reference Configuration Summary
Selected Mode SENSE Voltage Resulting VREF (V) Resulting Differential Span (V p-p)
External Reference AVDD N/A 2 × External Reference
Programmable Reference 0.2 V to VREF 0.5 × (1 + R2/R1) 2 × VREF (see Figure 48)
Internal Fixed Reference AGND to 0.2 V 1.0 2.0
Note: The optimum performance is obtained with VREF =
1.0 V; performance degrades as VREF (and full scale) reduces
(see Figure 25). In all reference configurations, REFT and REFB
drive the ADC core and establish its input span. The input
range of the ADC always equals twice the voltage at the reference pin for either an internal or an external reference.
The use of an external reference may be necessary to enhance
the gain accuracy of the ADC or to improve the thermal drift
characteristics. When multiple ADCs track one another, a single
reference (internal or external) may be necessary to reduce gain
matching errors to an acceptable level. A high precision external
reference may also be selected to provide lower gain and offset
temperature drift. Figure 49 shows the typical drift
characteristics of the internal reference.
When the SENSE pin is tied to AVDD, the internal reference is
disabled, allowing the use of an external reference. An internal
reference buffer loads the external reference with an equivalent
7 kΩ load. The internal buffer still generates the positive and
negative full-scale references, REFT and REFB, for the ADC
core. The input span is always twice the value of the reference
voltage; therefore, the external reference must be limited to a
maximum of 1 V. If the internal reference of the AD9216 is
used to drive multiple converters to improve gain matching,
the loading of the reference by the other converters must be
considered. Figure 50 depicts how the internal reference
voltage is affected by loading.
The shared reference mode allows the user to connect
the references from the dual ADCs together externally for
superior gain and offset matching performance. If the ADCs
are to function independently, the reference decoupling can
be treated independently and can provide superior isolation
04775-015
between the dual channels. To enable shared reference mode,
the SHARED_REF pin must be tied high, and the external
differential references must be externally shorted. (REFT_A
must be externally shorted to REFT_B, and REFB_A must
be shorted to REFB_B.)
Rev. A | Page 25 of 40
AD9216
DUAL ADC LFCSP PCB
The PCB requires a low jitter clock source, analog sources,
and power supplies. The PCB interfaces directly with ADI’s
standard dual-channel data capture board (HSC-ADC-EVALDC), which together with ADI’s ADC Analyzer™ software
allows for quick ADC evaluation.
POWER CONNECTOR
Power is supplied to the board via three detachable
4-lead power strips.
Table 10. Power Connector
Terminal Comments
VCC1 3.0 V Analog supply for ADC
VDD1 2.5 V Output supply for ADC
VDL1 2.5 V Buffer supply
VCLK 3.0 V Supply for XOR Gates
+5 V Optional op amp supply
−5 V Optional op amp supply
1
VCC, VDD, and VDL are the minimum required power connections.
ANALOG INPUTS
The evaluation board accepts a 2 V p-p analog input signal
centered at ground at two SMB connectors, Input A and
Input B. These signals are terminated at their respective
primary side transformer. T1 and T2 are wideband RF
transformers that provide the single-ended-to-differential
conversion, allowing the ADC to be driven differentially,
minimizing even-order harmonics. The analog signals can
be low-pass filtered at the secondary transformer to reduce
high frequency aliasing.
OPTIONAL OPERATIONAL AMPLIFIER
The PCB has been designed to accommodate an optional
AD8139 op amp that can serve as a convenient solution
for dc-coupled applications. To use the AD8139 op amp,
remove C14, R4, R5, C13, R37, and R36, and place R22, R23,
R30, and R24.
CLOCK
The single-clock input is at J5; the input clock is buffered and
drives both channel input clocks from Pin 3 at U8 through R79,
R40, and R85. Jumper E11 to E19 allows for inverting the input
clock. U8 also provides CLKA and CLKB outputs, which are
buffered by U6 and U5, which drive the DRA and DRB signals
(these are the data-ready clocks going off card). DRA and DRB
can also be inverted at their respective jumpers.
Table 11. Jumpers
Terminal Comments
OEB A Output Enable for A Side
PWDN A Power-Down A
MUX Mux Input
SHARED REF Shared Reference Input
DRA Invert DRA
LATA Invert A Latch Clock
ENC A Invert Encode A
OEB B Output Enable for B Side
PWDN B Power-Down B
DFS Data Format Select
SHARED REF Shared Reference Input
DRB Invert DRB
LATB Invert B Latch Clock
ENC B Invert Encode B
VOLTAGE REFERENCE
The ADC SENSE pin is brought out to E41, and the internal
reference mode is selected by placing a jumper from E41 to
ground (E27). External reference mode is selected by placing a
jumper from E41 to E25 and E30 to E2. R56 and R45 allow for
programmable reference mode selection.
DATA OUTPUTS
The ADC outputs are buffered on the PCB at U2, U4. The ADC
outputs have the recommended series resistors in line to limit
switching transient effects on ADC performance.
Rev. A | Page 26 of 40
AD9216
LFCSP EVALUATION BOARD BILL OF MATERIALS (BOM)
Table 12. Dual CSP PCB Rev. B
No. Quan. Reference Designator Device Package Value
The AD9216 LFCSP package has an integrated heat slug that
improves the thermal and electrical properties of the package
when locally attached to a ground plane at the PCB. A thermal
(filled) via array to a ground plane beneath the part provides
a path for heat to escape the package, lowering junction
temperature. Improved electrical performance also results
from the reduction in package parasitics due to proximity
of the ground plane. Recommended array is 0.3 mm vias
on 1.2 mm pitch. θ
configuration. Soldering the slug to the PCB is a requirement for this package.
= 26.4°C/W with this recommended
JA
Figure 60. Thermal Via Array
04775-047
Rev. A | Page 37 of 40
AD9216
OUTLINE DIMENSIONS
BSC SQ
PIN 1
INDICATOR
9.00
TOP
VIEW
8.75
BSC SQ
0.60 MAX
49
48
0.60 MAX
EXPOSED PAD
(BOTTOM VIEW)
0.30
0.25
0.18
64
1
PIN 1
INDICATOR
*
4.85
4.70 SQ
4.55
1.00
0.85
0.80
12° MAX
SEATING
PLANE
0.45
0.40
0.35
0.80 MAX
0.65 TYP
0.50 BSC
*
COMPLIANT TO JEDEC STANDARDS MO-220-VMMD
EXCEPT FOR EXPOSED PAD DIMENSION
0.05 MAX
0.02 NOM
0.20 REF
33
32
7.50
REF
16
17
Figure 61. 64-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
9 × 9 mm Body, Very Thin Quad (CP-64-1)
Dimensions shown in millimeters
ORDERING GUIDE
Model Temperature Range Package Description Package Option
AD9216BCPZ-65
AD9216BCPZRL7-651 −40°C to +85°C 64-Lead Lead Frame Chip Scale Package (LFCSP-VQ) CP-64-1
AD9216BCPZ-801 −40°C to +85°C 64-Lead Lead Frame Chip Scale Package (LFCSP-VQ) CP-64-1
AD9216BCPZRL7-801 −40°C to +85°C 64-Lead Lead Frame Chip Scale Package (LFCSP-VQ) CP-64-1
AD9216BCPZ-1051 −40°C to +85°C 64-Lead Lead Frame Chip Scale Package (LFCSP-VQ) CP-64-1
AD9216BCPZRL7-1051 −40°C to +85°C 64-Lead Lead Frame Chip Scale Package (LFCSP-VQ) CP-64-1
AD9216-80PCB
AD9216-105PCB Evaluation Board with AD9216BCPZ-105
1
Z = Pb-free part.
2
Supports AD9216-65 and AD9216-80 Evaluation.
1
2
−40°C to +85°C 64-Lead Lead Frame Chip Scale Package (LFCSP-VQ) CP-64-1