AD AD9057BRS-80 8-bit 40 msps/50 msps/80 msps converter Datasheet

a
8-Bit
40 MSPS/50 MSPS/80 MSPS Converter
AD9057
FEATURES
8-Bit, Low Power ADC: 200 mW Typical
120 MHz Analog Bandwidth
On-Chip 2.5 V Reference and T/H
1 V p-p Analog Input Range
Single 5 V Supply Operation
5 V or 3 V Logic Interface
Power-Down Mode: < 10 mW
Three Performance Grades (40 MSPS, 60 MSPS, 80 MSPS)
APPLICATIONS
Digital Communications (QAM Demodulators)
RGB and YC/Composite Video Processing
Digital Data Storage Read Channels
Medical Imaging
Digital Instrumentation
PRODUCT DESCRIPTION
The AD9057 is an 8-bit monolithic analog-to-digital converter
optimized for low cost, low power, small size, and ease of use.
With a 40 MSPS, 60 MSPS, or 80 MSPS encode rates capability and full-power analog bandwidth of 120 MHz, the component
is ideal for applications requiring excellent dynamic performance.
To minimize system cost and power dissipation, the AD9057
includes an internal 2.5 V reference and a track-and-hold
circuit. The user must provide only a 5 V power supply and an
encode clock. No external reference or driver components are
required for many applications.
The AD9057’s encode input is TTL/CMOS compatible and the
8-bit digital outputs can be operated from 5 V or 3 V supplies. A
power-down function may be exercised to bring total consumption to < 10 mW. In power-down mode the digital outputs are
driven to a high impedance state.
Fabricated on an advanced BiCMOS process, the AD9057 is
available in a space saving 20-lead surface mount plastic package (20 SSOP) and is specified over the industrial (–40°C to
+85°C) temperature range.
FUNCTIONAL BLOCK DIAGRAM
PWRDN
VD
VDD
AD9057
AIN
ADC
T/H
8
D7–D0
1k⍀
BIAS OUT
VREF IN
VREF OUT
+2.5V
ENCODE
GND
Customers desiring multichannel digitization may consider the
AD9059, a dual 8-bit, 60 MSPS monolithic based on the
AD9057 ADC core. The AD9059 is available in a 28-lead surface mount plastic package (28 SSOP) and is specified over the
industrial temperature range.
PIN CONFIGURATION
PWRDN 1
20 D0 (LSB)
VREF OUT 2
19 D1
VREF IN 3
18 D2
GND 4
AD9057
17 D3
VD 5
TOP VIEW 16 GND
(Not to Scale)
BIAS OUT 6
15 VDD
AIN 7
14 D4
VD 8
13 D5
GND 9
12 D6
ENCODE 10
11 D7 (MSB)
REV. C
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties that
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 2001
AD9057–SPECIFICATIONS (V = 5 V, V
D
Parameter
Temp
Test
Level
= 3 V; external reference, unless otherwise noted.)
AD9057BRS-40
Min
Typ
Max
RESOLUTION
DC ACCURACY
Differential Nonlinearity
DD
AD9057BRS-60
Min
Typ
Max
8
8
Bits
0.75
0.75
0.75
1.9
2.0
0.75
1.9
2.0
GUARANTEED
–6
–2.5
+6
–8
+8
± 70
LSB
LSB
LSB
LSB
1.0
±0
V p-p
mV
mV
kΩ
pF
µA
µA
MHz
I
VI
I
VI
VI
I
VI
V
25°C
25°C
Full
25°C
25°C
25°C
Full
25°C
V
I
VI
V
V
I
VI
V
BANDGAP REFERENCE
Output Voltage
Temperature Coefficient
Full
Full
VI
V
2.4
SWITCHING PERFORMANCE
Maximum Conversion Rate
Minimum Conversion Rate
Aperture Delay (tA)
Aperture Uncertainty (Jitter)
Output Valid Time (tV)2
Output Propagation Delay (tPD)2
Full
Full
25°C
25°C
Full
Full
VI
IV
V
V
IV
IV
40
25°C
25°C
V
V
25°C
25°C
I
V
42
45.5
44.0
42
45
43.5
25°C
25°C
I
V
6.7
7.2
7.0
6.7
25°C
25°C
I
V
43
46.5
45.5
25°C
25°C
I
V
–50
25°C
25°C
I
V
–46
25°C
25°C
25°C
V
V
V
Full
Full
Full
Full
25°C
25°C
25°C
VI
VI
VI
VI
V
IV
IV
No Missing Codes
Gain Error1
Gain Tempco1
ANALOG INPUT
Input Voltage Range
(Centered at 2.5 V)
Input Offset Voltage
Input Resistance
Input Capacitance
Input Bias Current
Analog Bandwidth
DYNAMIC PERFORMANCE3
Transient Response
Overvoltage Recovery Time
Signal-to-Noise Ratio (SINAD)
(With Harmonics)
fIN = 10.3 MHz
fIN = 76 MHz
Effective Number of Bits
fIN = 10.3 MHz
fIN = 76 MHz
Signal-to-Noise Ratio (SNR)
(Without Harmonics)
fIN = 10.3 MHz
fIN = 76 MHz
2nd Harmonic Distortion
fIN = 10.3 MHz
fIN = 76 MHz
3rd Harmonic Distortion
fIN = 10.3 MHz
fIN = 76 MHz
Two Tone Intermodulation
Distortion (IMD)
Differential Phase
Differential Gain
DIGITAL INPUTS
Logic “1” Voltage
Logic “0” Voltage
Logic “1” Current
Logic “0” Current
Input Capacitance
Encode Pulsewidth High (tEH)
Encode Pulsewidth Low (tEL)
1.9
2.0
0.75
1.9
2.0
GUARANTEED
–6
–2.5
+6
–8
+8
± 70
–15
–25
1.0
±0
150
2
6
+15
+25
1.9
2.0
0.75
1.9
2.0
GUARANTEED
–6
–2.5
+6
–8
+8
± 70
–15
–25
2.5
± 10
1.0
±0
150
2
6
16
25
120
+15
+25
150
2
6
16
25
2.6
2.4
2.5
± 10
2.6
2.4
2.5
± 10
4.0
9
9
16
25
2.6
80
5
18.0
+15
+25
120
60
2.7
5
6.6
11.5
–15
–25
120
5
4.0
Unit
8
25°C
Full
25°C
Full
Full
25°C
Full
Full
Integral Nonlinearity
AD9057BRS-80
Min
Typ
Max
2.7
5
6.6
9.5
5
4.0
14.2
9
9
2.7
5
6.6
8.0
11.3
% FS
% FS
ppm/°C
V
ppm/°C
MSPS
MSPS
ns
ps, rms
ns
ns
9
9
ns
ns
41.5
45
43.5
dB
dB
7.2
6.9
6.6
7.2
6.9
Bits
Bits
43
46
45
42.5
46
45
dB
dB
–62
–54
–50
–62
–54
–50
–62
–54
dBc
dBc
–60
–54
–46
–60
–54
–46
–60
–54
dBc
dBc
–52
0.8
1.0
dBc
Degrees
%
–52
0.8
1.0
–52
0.8
1.0
2.0
2.0
2.0
0.8
±1
±1
0.8
±1
±1
4.5
9.0
9.0
4.5
166
166
–2–
0.8
±1
±1
6.7
6.7
4.5
166
166
5.5
5.5
166
166
V
V
µA
µA
pF
ns
ns
REV. C
AD9057
Parameter
Temp
Test
Level
AD9057BRS-40
Min
Typ
Max
AD9057BRS-60
Min
Typ
Max
AD9057BRS-80
Min
Typ
Max
DIGITAL OUTPUTS
Logic “1” Voltage (VDD = 3 V)
Logic “1” Voltage (VDD = 5 V)
Logic “0” Voltage
Output Coding
Full
Full
Full
VI
IV
VI
2.95
4.95
2.95
4.95
2.95
4.95
0.05
Offset Binary Code
0.05
Offset Binary Code
0.05
Offset Binary Code
Full
Full
Full
Full
VI
VI
VI
VI
36
4.0
192
6
38
5.5
205
6
40
7.4
220
6
25°C
I
POWER SUPPLY
VD Supply Current (VD = 5 V)
VDD Supply Current (VDD = 3 V)4
Power Dissipation5, 6
Power-Down Dissipation
Power Supply Rejection Ratio
(PSRR)
48
6.5
260
10
15
48
6.5
260
10
15
Unit
V
V
V
51
8.8
281
10
mA
mA
mW
mW
15
mV/V
NOTES
1
Gain error and gain temperature coefficient are based on the ADC only (with a fixed 2.5 V external reference).
2
tV and tPD are measured from the 1.5 V level of the ENCODE to the 10%/90% levels of the digital output swing. The digital output load during test is not to exceed
an ac load of 10 pF or a dc current of ± 40 µA.
3
SNR/harmonics based on an analog input voltage of –0.5 dBFS referenced to a 1.0 V full-scale input range.
4
Digital supply current based on V DD = 3 V output drive with <10 pF loading under dynamic test conditions.
5
Power dissipation is based on specified encode and 10.3 MHz analog input dynamic test conditions (V D = 5 V ± 5%, VDD = 3 V ± 5%).
6
Typical thermal impedance for the RS style (SSOP) 20-lead package: θJC = 46°C/W, θCA = 80°C/W, θJA = 126°C/W.
Specifications subject to change without notice.
EXPLANATION OF TEST LEVELS
Test Level
Description
I
II
100% Production Tested
100% Production Tested at 25°C and Sample
Tested at Specified Temperatures
Sample Tested Only
Parameter is Guaranteed by Design and Characterization Testing
Parameter is a Typical Value Only
100% Production Tested at 25°C; Guaranteed by Design and Characterization Testing
for Industrial Temperature Range
III
IV
V
VI
N
N+5
N+3
AIN
N+1
N+4
N+2
tA
ENCODE
tEH
tEL
tV
DIGITAL
OUTPUTS
N–3
N–2
N–1
N
N+1
tPD
MIN
tA
APERTURE DELAY
tEH
PULSEWIDTH HIGH
tEL
PULSEWIDTH LOW
tV
OUTPUT VALID TIME
tPD
OUTPUT PROP DELAY
TYP
166 ns
166 ns
4.0 ns
6.6 ns
9.5 ns
Figure 1. Timing Diagram
REV. C
MAX
2.7 ns
–3–
N+2
AD9057
ABSOLUTE MAXIMUM RATINGS
PIN FUNCTION DESCRIPTIONS
VD, VDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Analog Inputs . . . . . . . . . . . . . . . . . . . . –0.5 V to VD + 0.5 V
Digital Inputs . . . . . . . . . . . . . . . . . . . –0.5 V to VDD + 0.5 V
VREF Input . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to VD + 0.5 V
Digital Output Current . . . . . . . . . . . . . . . . . . . . . . . . 20 mA
Operating Temperature . . . . . . . . . . . . . . . . –55°C to +125°C
Storage Temperature . . . . . . . . . . . . . . . . . . –65°C to +150°C
Maximum Junction Temperature . . . . . . . . . . . . . . . . 150°C
Maximum Case Temperature . . . . . . . . . . . . . . . . . . . 150°C
ORDERING GUIDE
Temperature
Range
Model
Package Option*
AD9057BRS–40, –60, –80 –40°C to +85°C RS-20
AD9057/PCB
25°C
Evaluation Board
*RS = Shrink Small Outline (SSOP).
Pin No.
Mnemonic
Function
1
PWRDN
2
VREF OUT
3
VREF IN
4, 9, 16
5, 8
6
GND
VD
BIAS OUT
7
10
AIN
ENCODE
11–14, 17–20
15
D7–D4, D3–D0
VDD
Power-Down Function Select;
Logic HIGH for Power-Down
Mode (Digital Outputs Go to
High Impedance State).
Internal Reference Output
(2.5 V typ); Bypass with 0.1 µF
to Ground.
Reference Input for ADC (2.5 V
typ, ± 10%)
Ground (Analog/Digital)
Analog 5 V Power Supply
Bias Pin for AC Coupling
(1 kΩ to REF IN)
Analog Input for ADC
Encode Clock for ADC (ADC
Samples on Rising Edge of
ENCODE)
Digital Outputs of ADC
Digital Output Power Supply;
Nominally 3 V to 5 V.
Table I. Digital Coding (VREF = 2.5 V)
Analog Input
Voltage Level
Digital Output
3.0 V
2.502 V
2.498 V
2.0 V
Positive Full Scale
Midscale +1/2 LSB
Midscale –1/2 LSB
Negative Full Scale
1111 1111
1000 0000
0111 1111
0000 0000
PIN CONFIGURATION
PWRDN 1
20 D0 (LSB)
VREF OUT 2
19 D1
VREF IN 3
18 D2
GND 4
AD9057
17 D3
VD 5
TOP VIEW 16 GND
(Not to Scale)
BIAS OUT 6
15 VDD
AIN 7
14 D4
VD 8
13 D5
GND 9
12 D6
ENCODE 10
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although
the AD9057 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.
–4–
11 D7 (MSB)
WARNING!
ESD SENSITIVE DEVICE
REV. C
Typical Performance Characteristics–AD9057
0
–30
ENCODE = 60MSPS
ANALOG IN = 10.3MHz, –0.5dBFS
SINAD = 46.1dB
ENOB = 7.36 BITS
SNR = 46.5dB
–10
–20
–35
ENCODE = 60MSPS
AIN = –0.5dBFS
–40
–30
–45
–40
dB
dB
2ND HARMONIC
–50
–50
–55
–60
3RD HARMONIC
–60
–70
–65
–80
–90
0
–70
0
30
FREQUENCY – MHz
20
40
60
80
100
120
140
160
ANALOG INPUT FREQUENCY – MHz
TPC 4. Harmonic Distortion vs. AIN Frequency
TPC 1. Spectral Plot 60 MSPS, 10.3 MHz
0
0
ENCODE = 60MSPS
ANALOG IN = 76MHz, –0.5dBFS
–10 SINAD = 44.9dB
ENOB = 7.16 BITS
–20 SNR = 45.2dB
–20
–30
–30
–40
–40
ENCODE = 60MSPS
F1 IN = 9.5MHz @ –7.0dBFS
F2 IN = 9.9MHz @ –7.0dBFS
2F1 - F2 = –52.0dBc
2F2 - F1 = –53.0dBc
dB
dB
–10
–50
–50
–60
–60
–70
–70
–80
–80
–90
–90
0
0
30
FREQUENCY – MHz
TPC 2. Spectral Plot 60 MSPS, 76 MHz
10
20
FREQUENCY – MHz
30
TPC 5. Two-Tone Intermodulation Distortion
54
48
SNR
46
SNR
48
44
42
42
SINAD
SINAD
36
dB
dB
40
ENCODE = 60MSPS
AIN = –0.5dBFS
38
30
AIN = 10.3MHz, –0.5dBFS
24
36
18
34
12
32
30
0
20
40
60
80
100
120
140
0
5
160
ANALOG INPUT FREQUENCY – MHz
20
30
40
50
60
ENCODE RATE – MSPS
70
80
TPC 6. SINAD/SNR vs. Encode Rate
TPC 3. SINAD/SNR vs. AIN Frequency
REV. C
10
–5–
90
AD9057
12.0
350
11.0
300
VDD = 3V
10.0
VDD = 5V
250
9.5
9.0
tPD – ns
mW
200
VDD = 3V
150
8.5
8.0
VDD = 5V
7.5
100
AIN = 10.3MHz, –0.5dBFS
7.0
50
6.5
0
5
10
20
30
40
50
60
ENCODE RATE – MSPS
70
80
6.0
–45
90
TPC 7. Power Dissipation vs. Encode Rate
0
25
TEMPERATURE – C
70
90
TPC 10. tPD vs. Temperature/Supply (VDD = 3 V/5 V)
46.5
46.5
46.0
46.0
SNR
SNR
45.5
45.5
45.0
dB
dB
45.0
SINAD
44.5
44.0
ENCODE = 60MSPS
AIN = 10.3MHz, –0.5dBFS
43.5
44.5
44.0
SINAD
43.0
43.5
42.5
43.0
42.0
41.5
–45
0
25
TEMPERATURE – C
70
ENCODE = 60MSPS
AIN = 10.3MHz, –05dBFS
42.5
5.8
90
TPC 8. SINAD/SNR vs. Temperature
6.7
7.5
10.0
8.35
9.2
ENCODE HIGH PULSEWIDTH – ns
10.9
TPC 11. SINAD/SNR vs. Encode Pulsewidth
0
0
–0.2
–1
–2
–0.4
ADC GAIN – dB
GAIN ERROR – %
–3
–0.6
–0.8
–1.0
–1.2
–5
–6
–7
–1.4
–8
–1.6
–1.8
–45
ENCODE = 60MSPS
AIN = –0.5dBFS
–4
–9
–10
0
25
TEMPERATURE – C
70
90
1
TPC 9. ADC Gain vs. Temperature (with External
2.5 V Reference)
2
5
10
20
50
100
ANALOG FREQUENCY – MHz
200
500
TPC 12. ADC Frequency Response
–6–
REV. C
AD9057
5V
THEORY OF OPERATION
The AD9057 combines Analog Devices’ proprietary MagAmp
gray code conversion circuitry with flash converter technology
to provide a high performance, low cost ADC. The design
architecture ensures low power, high speed, and 8-bit accuracy.
A single-ended TTL/CMOS compatible ENCODE input controls
ADC timing for sampling the analog input pin and strobing the
digital outputs (D7–D0). An internal voltage reference (VREF
OUT) may be used to control ADC gain and offset or an external reference may be applied.
The analog input signal is buffered at the input of the ADC and
applied to a high speed track-and-hold. The T/H circuit holds the
analog input value during the conversion process (beginning with
the rising edge of the ENCODE command). The T/H’s output
signal passes through the gray code and flash conversion stages
to generate coarse and fine digital representations of the held
analog input level. Decode logic combines the multistage data
and aligns the 8-bit word for strobed outputs on the rising edge
of the ENCODE command. The MagAmp/Flash architecture of
the AD9057 results in three pipeline delays for the output data.
USING THE AD9057
Analog Inputs
The AD9057 provides a single-ended analog input impedance
of 150 kΩ. The input requires a dc bias current of 6 µA (typical)
centered near 2.5 V (± 10%). The dc bias may be provided by
the user or may be derived from the ADC’s internal voltage
reference. Figure 2 shows a low cost dc bias implementation
allowing the user to capacitively couple ac signals directly into
the ADC without additional active circuitry. For best dynamic
performance, the VREF OUT pin should be decoupled to
ground with a 0.1 µF capacitor (to minimize modulation of
the reference voltage) and the bias resistor should be approximately 1 kΩ. A 1 kΩ bias resistor (± 20%) is included within
the AD9057 and may be used to reduce application board size
and complexity.
5V
REF OUT
0.1␮F
REF IN
1k⍀
BIAS OUT
VIN
(1V p-p)
0.1␮F
AIN
AD9057
Figure 2. Capacitively Coupled AD9057
Figure 3 shows typical connections for high-performance dc
biasing using the ADC’s internal voltage reference. All components may be powered from a single 5 V supply (in the example,
analog input signals are referenced to ground).
REV. C
REF OUT
10k⍀
AD9057
10k⍀
0.1␮F
5V
REF IN
AD8041
VIN
(–0.5V
TO +0.5V)
AIN
1k⍀
1k⍀
Figure 3. DC-Coupled AD9057 (Inverted VIN)
Voltage Reference
A stable and accurate 2.5 V voltage reference is built into the
AD9057 (VREF OUT). The reference output may be used to
set the ADC gain/offset by connecting VREF OUT to VREF IN.
The internal reference is capable of providing 300 µA of drive
current (for dc biasing the analog input or other user circuitry).
Some applications may require greater accuracy, improved
temperature performance, or gain adjustments that cannot be
obtained using the internal reference. An external voltage may
be applied to the VREF IN with VREF OUT disconnected for
gain adjustment of up to ± 10% (the VREF IN pin is internally
tied directly to the ADC circuitry). ADC gain and offset will
vary simultaneously with external reference adjustment with a
1:1 ratio (a 2% or 50 mV adjustment to the 2.5 V reference
varies ADC gain by 2% and ADC input range center offset by
50 mV). Theoretical input voltage range versus reference input
voltage may be calculated from the following equations:
VRANGE (p-p)
= VREF IN/2.5
VMIDSCALE
= VREF IN
VTOP-OF-RANGE
= VREF IN + VRANGE/2
VBOTTOM-OF-RANGE = VREF IN – VRANGE/2
Digital Logic (5 V/3 V Systems)
The digital inputs and outputs of the AD9057 can easily be
configured to interface directly with 3 V or 5 V logic systems.
The ENCODE and power-down (PWRDN) inputs are CMOS
stages with TTL thresholds of 1.5 V, making the inputs compatible with TTL, 5 V CMOS, and 3 V CMOS logic families. As
with all high-speed data converters, the encode signal should be
clean and jitter free to prevent degradation of ADC dynamic
performance.
The AD9057’s digital outputs will also interface directly with
5 V or 3 V CMOS logic systems. The voltage supply pin (VDD)
for these CMOS stages is isolated from the analog VD voltage
supply. By varying the voltage on this supply pin the digital
output HIGH level will change for 5 V or 3 V systems. Optimum
SNR is obtained running the outputs at 3 V. Care should be
taken to isolate the VDD supply voltage from the 5 V analog
supply to minimize digital noise coupling into the ADC.
–7–
AD9057
The AD9057 provides high impedance digital output operation
when the ADC is driven into power-down mode (PWRDN, logic
HIGH). A 200 ns (minimum) power-down time should be
provided before a high impedance characteristic is required at
the outputs. A 200 ns power-up period should be provided to
ensure accurate ADC output data after reactivation (valid output data is available three clock cycles after the 200 ns delay).
full-power analog bandwidth of 2× the maximum sampling rate,
the ADC provides sufficient pixel to pixel transient settling time
to ensure accurate 60 MSPS video digitization. Figure 5 shows a
typical RGB video digitizer implementation for the AD9057.
RED
AD9057
GREEN
AD9057
BLUE
AD9057
Timing
8
The AD9057 is guaranteed to operate with conversion rates from
5 MSPS to 80 MSPS depending on grade. The ADC is designed
to operate with an encode duty cycle of 50%, but performance
is insensitive to moderate variations. Pulsewidth variations of
up to ± 10% (allowing the encode signal to meet the minimum/
maximum HIGH/LOW specifications) will cause no degradation in ADC performance (see Figure 1 timing diagram).
8
PIXEL CLOCK
H-SYNC
PLL
Figure 5. RGB Video Encoder
Power Dissipation
The power dissipation of the AD9057 is specified to reflect a
typical application setup under the following conditions: analog
input is –0.5 dBFS at 10.3 MHz, VD is 5 V, VDD is 3 V, and digital
outputs are loaded with 7 pF typical (10 pF maximum). The
actual dissipation will vary as these conditions are modified in
user applications. TPC 7 shows typical power consumption for the
AD9057 versus ADC encode frequency and VDD supply voltage.
Evaluation Board
A power-down function allows users to reduce power dissipation
when ADC data is not required. A TTL/CMOS HIGH signal
(PWRDN) shuts down portions of the ADC and brings total
power dissipation to less than 10 mW. The internal bandgap
voltage reference remains active during power-down mode to
minimize ADC reactivation time. If the power-down function is
not desired, Pin 1 should be tied to ground.
APPLICATIONS
The wide analog bandwidth of the AD9057 makes it attractive for
a variety of high-performance receiver and encoder applications.
Figure 4 shows two ADCs in a typical low cost I and Q demodulator implementation for cable, satellite, or wireless LAN modem
receivers. The excellent dynamic performance of the ADC at
higher analog input frequencies and encode rates empowers
users to employ direct IF sampling techniques (refer to TPC 2
spectral plot). IF sampling eliminates or simplifies analog mixer
and filter stages to reduce total system cost and power.
IF IN
8
BPF
AD9057
BPF
AD9057
For dc-coupled analog input applications, amplifier U2 is configured to operate as a unity gain inverter with adjustable offset
for the analog input signal. For full-scale ADC drive, the analog
input signal should be 1 V p-p into 50 Ω (R1) referenced to
ground (0 V). The amplifier offsets the analog signal by +VREF
(2.5 V typical) to center the voltage for proper ADC input drive.
For dc-coupled operation, connect E1 to E2 (analog input to
R2) and E11 to E12 (amplifier output to analog input of AD9057)
using the board jumper connectors. DC offset of the analog
input signal can be modified by adjusting potentiometer R10.
For ac-coupled analog input applications, amplifier U2 is
removed from the analog signal path. The analog signal is
coupled into the input of the AD9057 through capacitor C2.
The ADC pulls analog input bias current from the VREF IN
voltage through the 1 kΩ resistor internal to the AD9057 (BIAS
OUT). The analog input signal to the board should be 1 V p-p
into 50 Ω (R1) for full-scale ADC drive. For ac-coupled operation,
connect E1 to E3 (analog input A to C2 feedthrough capacitor)
and E10 to E12 (C2 to the analog input and internal bias resistor) using the board jumper connectors.
90
VCO
The AD9057/PCB evaluation board provides an easy-to-use
analog/digital interface for the 8-bit, 60 MSPS ADC. The board
includes typical hardware configurations for a variety of highspeed digitization evaluations. On-board components include
the AD9057 (in the 20-lead SSOP package), an optional analog
input buffer amplifier, a digital output latch, board timing drivers, an analog reconstruction digital-to-analog converter, and
configurable jumpers for ac coupling, dc coupling, and powerdown function testing. The board is configured at shipment for
dc coupling using the AD9057’s internal voltage reference.
The on-board reference voltage may be used to drive the ADC
or an external reference may be applied. To use the internal
voltage reference, connect E6 to E5 (VREF OUT to VREF IN).
To apply an external voltage reference, connect E4 to E5
(external reference from the REF banana jack to VREF IN).
The external voltage reference should be 2.5 V ± 10%.
VCO
Figure 4. I and Q Digital Receiver
The high sampling rate and analog bandwidth of the AD9057
are ideal for computer RGB video digitizer applications. With a
–8–
REV. C
AD9057
The power-down function of the AD9057 can be exercised
through a board jumper connection. Connect E7 to E9 (5 V to
PWRDN) for power-down operation. For normal operation,
connect E8 to E9 (ground to PWRDN).
The encode signal source should be TTL/CMOS compatible
and capable of driving a 50 Ω termination (R7). The digital
outputs of the AD9057 are buffered through latches on the
evaluation board (U3) and are available for the user at connector Pins 30–37. Latch timing is derived from the ADC ENCODE
clock and a digital clocking signal is provided for the board
user at connector Pins 2 and 21.
An on-board reconstruction digital-to-analog converter is
available for quick evaluations of ADC performance using an
oscilloscope or spectrum analyzer. The DAC converts the
ADC’s digital outputs to an analog signal for examination at
the DAC OUT connector. The DAC is clocked at the ADC
ENCODE frequency. The AD9760 is a 10-bit/100 MSPS single
5 V supply DAC. The reconstruction signal facilitates quick
system troubleshooting or confirmation of ADC functionality
without requiring external digital memory, timing, or display
interfaces. The DAC can be used for limited dynamic testing,
but customers should note that test results will be based on the
combined performance of the ADC and DAC (the best ADC
performance will be recognized by evaluating the digital outputs
of the ADC directly).
VD
VD
ENCODE
500⍀
VREFIN
AIN
PWRDN
Digital Inputs
Analog Input
VDD, 3V TO 5V
VD
1k⍀
VREFIN
D0–D7
Digital Outputs
BIAS OUT
Bias Output
VD
VD
3k⍀
VREFIN
VREFOUT
2.5k⍀
VREF Output
VREF Input
Figure 6. Equivalent Circuits
REV. C
–9–
AD9057
5V
J6, REF
ANALOG IN
E2
BNC
J1
1
NC
2
3
4
–VS
E1
E3
C37DRPF
P2
E4
DIS
+VS
NC
E5
8
7
6
5
E6
R5
2k⍀
R10
500
R3
1k⍀
R1
50⍀
PWRDN
E9
E8
C17
0.1␮F
U2
AD8041Q
R2
1k⍀
GND
E7
R4
2k⍀
R6
10⍀
C1
0.1␮F
GND
5V
E11
5V
GND
E12
E10
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
BIAS OUT
14
AIN
D4 13
VD
D5 12
GND
D6 11
ENC
(MSB) D7
PWRDN
REF OUT
REF IN
GND
VD
(LSB) D0
D1
D2
D3
GND
VDD
D0
D1
D2
D3
GND
VDD
D4
D5
D6
D7
U3
74ACQ574
D7
D6
D5
D4
D3
D2
D1
D0
9
8
7
6
5
4
3
2
8Q
7Q
6Q
5Q
4Q
3Q
2Q
1Q
OE
8D
7D
6D
5D
4D
3D
2D
1D
CK
11
12
13
14
15
16
17
18
19
DA7
DA6
DA5
DA4
DA3
DA2
DA1
DA0
1
C2
0.1␮F
BNC
J3
1
2
ENCODE
R7
50⍀
4
5
12
13
9
10
U4
74AC00
3
U4
74AC00
C10
0.1␮F
+
DA7
DA6
DA5
DA4
DA3
DA2
DA1
DA0
GND
GND
6
U4
74AC00
11
U4
74AC00
8
ANALOG
RECONSTRUCT
DAC OUT
VDD
J7, VDD
28
C11
10␮F
1
2
3
4
5
6
7
8
9
10
BNC
J2
DAC
AD9760AR
CLK
DVDD
(MSB)
DB9
AVDD
DB8
COMP2
DB7
COMP1
DB6
DB5
DB4
DB3
DB2
DB1
DB0
FSADJ
SLEEP
5V
5V
C18
0.1␮F
23
19
C19
0.1␮F
18
17
REFIO
16
REFLO
(LSB)
IOUT
A
B
22
21
R8
50⍀
5V
27
24
R9
2k⍀
15
C13
0.1␮F
DA0
DA1
DA2
DA3
DA4
DA5
DA6
DA7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
PWRDN
R11
50⍀
J4, GND
C7
0.1␮F
C8
0.1␮F
C14
0.1␮F
J5, 5V
C3
0.1␮F
C4
0.1␮F
C5
0.1␮F
+
C9
0.1␮F
C12
10␮F
DECOUPLING CAPS
Figure 7. Evaluation Board Schematic
–10–
REV. C
AD9057
Figure 8. Evaluation Board Layout
REV. C
–11–
AD9057
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
C00561b–0–9/01(C)
20-Lead SSOP
(RS-20)
0.295 (7.50)
0.271 (6.90)
11
1
10
0.212 (5.38)
0.205 (5.21)
0.311 (7.9)
0.301 (7.64)
20
0.07 (1.78)
0.066 (1.67)
0.078 (1.98) PIN 1
0.068 (1.73)
0.008 (0.203)
0.002 (0.050)
0.0256
(0.65)
BSC
SEATING
PLANE
0.009 (0.229)
0.005 (0.127)
8ⴗ
0ⴗ
0.037 (0.94)
0.022 (0.559)
Revision History
Location
Page
Data Sheet changed from REV. B to REV. C.
PRINTED IN U.S.A.
Edit to ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
–12–
REV. C