Cadeka CDK1303 8-bit, 1 gsps, flash a/d converter Datasheet

Data Sheet
A m p l i fy t h e H u m a n E x p e r i e n c e
CDK1303
8-bit, 1 GSPS, Flash A/D Converter
n
1:2 Demuxed ECL compatible outputs
n
Wide input bandwidth – 900MHz
n
Low input capacitance – 15pF
n
Metastable errors reduced to 1 LSB
n
Gray code output
The CDK1303 is a full parallel (flash) analog-to-digital converter capable
of digitizing full scale (0 to -2V) inputs into eight-bit digital words at an
update rate of 1 GSPS. The ECL-compatible outputs are demultiplexed into
two separate output banks, each with differential data ready outputs to ease
the task of data capture. The CDK1303’s wide input bandwidth and low
capacitance eliminate the need for external track-and-hold amplifiers for most
applications. A proprietary decoding scheme reduces metastable errors to the
1 LSB level. The CDK1303 operates from a single -5.2V supply, with a nominal
power dissipation of 5.5W.
Applications
n
Digital oscilloscopes
n
Transient capture
n
Radar, EW, and ECM
n
Direct RF down-conversion
The CDK1303 is available in an 80-lead surface-mount MQUAD package over
the industrial temperature range (-25°C to +85°C).
Block Diagram
CDK1303 8-bit, 1 GSPS, Flash A/D Converter
General Description
features
REV 1A
Ordering Information
Part Number
Package
Pb-Free
RoHS Compliant
Operating Temperature Range
Packaging Method
CDK1303AEMQ80
MQUAD-80
Yes
Yes
-25°C to +85°C
Rail
CDK1303AEMQ80_Q
MQUAD-80
No
No
-25°C to +85°C
Rail
CDK1303BEMQ80
MQUAD-80
Yes
Yes
-25°C to +85°C
Rail
CDK1303BEMQ80_Q
MQUAD-80
No
No
-25°C to +85°C
Rail
Moisture sensitivity level for all parts is MSL-1.
©2008 CADEKA Microcircuits LLC www.cadeka.com
Data Sheet
Pin Configuration
MQUAD-80
CDK1303 8-bit, 1 GSPS, Flash A/D Converter
CDK1303
Pin Name
VEE
AGND
Description
Negative Supply Nominally -5.2V
Analog Ground
VRTF
Reference Voltage Force Top, Nominally 0V
VRTS
Reference Voltage Sense Top
VRM
Reference Voltage Middle, Nominally -1V
VRBF
Reference Voltage Force Bottom, Nominally -2V
VRBS
Reference Voltage Sense Bottom
VIN
Analog Input Voltage, Can Be Either Voltage or Sense
DGND
REV 1A
Pin Assignments
Digital Ground
D0-D7A
Data Output Bank A
D0-D7B
Data Output Bank B
DRA
Data Ready Bank A
DRA
Not Data Ready Bank A
DRB
Data Ready Bank B
DRB
Not Data Ready Bank B
D8A
Overrange Output Bank A
D8B
Overrange Output Bank B
CLK
Clock Input
CLK
Clock Input
©2008 CADEKA Microcircuits LLC www.cadeka.com
2
Data Sheet
Absolute Maximum Ratings
The safety of the device is not guaranteed when it is operated above the “Absolute Maximum Ratings”. The device
should not be operated at these “absolute” limits. Adhere to the “Recommended Operating Conditions” for proper
device function. The information contained in the Electrical Characteristics tables and Typical Performance plots reflect
the operating conditions noted on the tables and plots.
Supply Voltages
Negative Supply Voltage (VEE to GND)
Ground Voltage Differential
Input Voltages
Analog Input
Reference Input
Digital Input
Reference Current Input (VRT to VRB)
Min
Max
Unit
-7.0
-0.5
+0.5
+0.5
V
V
+0.5
+0.5
+0.5
VEE +0.5
VEE +0.5
VEE +0.5
35
V
V
V
mA
0
-28
mA
Output Voltages
Digital Output Current
CDK1303 8-bit, 1 GSPS, Flash A/D Converter
Parameter
Reliability Information
Parameter
Min
Storage Temperature Range
-65
Typ
Max
Unit
+150
°C
Max
Unit
+85
+125
+150
+300
°C
°C
°C
°C
Recommended Operating Conditions
Min
Operating Temperature Range - ambient
Operating Temperature - case
Operating Temperature - junction
Lead Temperature, (soldering 10 seconds)
-25
©2008 CADEKA Microcircuits LLC Typ
www.cadeka.com
REV 1A
Parameter
3
Data Sheet
Electrical Characteristics
(TJ = TC = TA = +25°C , VEE = -5.2V, VRB = -2.0V, VRM = -1.0V, VRT = 0.00V, ƒCLK = 1GHz, Duty Cycle=50%,
unless otherwise specified)
CDK1303A
Symbol
Parameter
Conditions
Min
Max
Min
8
Typ
Max
8
Units
CDK1303 8-bit, 1 GSPS, Flash A/D Converter
Resolution
Typ
CDK1303B
bits
DC Performance
DLE
Differential Linearity Error(1)
ƒclk = 100MHz
-0.85
+0.95
-0.95
+1.5
LSB
ILE
Integral Linearity Error(1)
ƒclk = 100MHz
-1.0
+1.0
-1.5
+1.5
LSB
No Missing Codes
Guaranteed
Guaranteed
Analog Input
Input Voltage Range(1)
Input Bias Current(1)
VRB
VIN = 0V
Input Resistance
Input Capacitance
Input Bandwidth
Offset Error
VRT
0.75
VRB
2.0
0.75
VRT
V
2.0
mA
15
15
15
15
pF
Small Signal
900
900
MHz
Large Signal
500
500
MHz
Over Full Input Range
kΩ
(2)
VRT
-30
+30
-30
+30
Offset Error(2)
VRB
-30
+30
-30
+30
mV
mV
Input Slew Rate
5
5
V/ns
Clock Synchronous Input Currents
2
2
μA
80
Ω
30
MHz
Reference Input
60
Ladder Resistance(1)
Reference Bandwidth
80
60
30
Timing Characteristics
Aperture Jitter
Acquisition Time
1
GHz
2
2
250
250
REV 1A
1
Maximum Sample Rate(1)
ps
ps
CLK to Data Delay(2)
0.9
1.4
1.9
0.9
1.4
1.9
ns
CLK to Data Ready Delay(2)
1.25
1.75
2.25
1.25
1.75
2.25
ns
Dynamic Performance
SNR
THD
SFDR
SINAD
Signal-to-Noise Ratio
Total Harmonic Distortion
Spurious Free Dynamic Range
Signal-to-Noise and Distortion
ƒIN = 50MHz(1)
ƒIN = 250MHz
45
43
dB
43
41
dB
ƒIN = 50MHz(1)
-44
-42
dBc
ƒIN = 250MHz(1)
-36
-34
dBc
ƒIN = 50MHz
(1)
47
43
dB
ƒIN = 250MHz(1)
39
35
dB
ƒIN = 50MHz(1)
42
40
dB
ƒIN = 250MHz
35
33
dB
(1)
(1)
Notes:
1. 100% production tested at +25°C.
2. Parameter is guaranteed (but not tested) by design and characterization data.
3. Typical Thermal Impedance: θJC = +4°C/W.
©2008 CADEKA Microcircuits LLC www.cadeka.com
4
Data Sheet
Electrical Characteristics
(TJ = TC = TA = +25°C , VEE = -5.2V, VRB = -2.0V, VRM = -1.0V, VRT = 0.00V, ƒCLK = 1GHz, Duty Cycle=50%,
unless otherwise specified)
CDK1303A
Symbol
Parameter
Conditions
Typ
-1.1
-0.7
Max
Min
Typ
-1.1
-0.7
Max
Units
CDK1303 8-bit, 1 GSPS, Flash A/D Converter
Min
CDK1303B
Dynamic Inputs
Input High Voltage(1)
CLK, CLK
Input Low Voltage
CLK, CLK
(1)
-1.8
-1.5
-1.8
V
-1.5
V
tPWH
Clock Pulse Width High(1)
0.5
0.4
0.5
0.4
ns
tPWL
Clock Pulse Width Low(1)
0.5
0.4
0.5
0.4
ns
Logic 1 Voltage(1)
-1.1
-0.9
-1.1
-0.9
Digital Outputs
Logic 0 Voltage(1)
-1.8
-1.5
-1.8
V
-1.5
V
Rise Time
20% to 80%
450
450
ps
Fall Time
20% to 80%
450
450
ps
Power Supply Requirements
VEE
Voltage Range(2)
IEE
Current
(1)
-4.95
VIN = 0V
Power Dissipation(1)
-5.2
-5.45
-4.95
-5.2
-5.45
V
1.05
1.2
1.05
1.2
A
5.5
6.25
5.5
6.25
W
Notes:
1. 100% production tested at +25°C.
2. Parameter is guaranteed (but not tested) by design and characterization data.
3. Typical Thermal Impedance: θJC = +4°C/W.
REV 1A
©2008 CADEKA Microcircuits LLC www.cadeka.com
5
Data Sheet
General Description
The CDK1303 has true differential analog and digital
data paths from the preamplifiers to the output buffers
(Current Mode Logic) for reducing potential missing codes
while rejecting common mode noise.
Signature errors are also reduced by careful layout of the
analog circuitry. The output drive capability of the device
can provide full ECL swings into 50Ω loads.
CDK1303 8-bit, 1 GSPS, Flash A/D Converter
The CDK1303 is one of the fastest monolithic 8-bit parallel
flash A/D converters available today. The nominal
conversion rate is 1 GSPS and the analog bandwidth is
in excess of 900MHz. A major advance over previous
flash converters is the inclusion of 256 input preamplifiers
between the reference ladder and input comparators
(see block diagram). This not only reduces clock transient
kickback to the input and reference ladder due to a low
AC beta, but also reduces the effect of the dynamic state
of the input signal on the latching characteristics of the
input comparators. The preamplifiers act as buffers and
stabilize the input capacitance so that it remains constant
over different input voltage and frequency ranges and
therefore makes the part easier to drive than previous
flash converters. The preamplifiers also add a gain of two
to the input signal so that each comparator has a wider
overdrive or threshold range to “trip” into or out of the
active state. This gain reduces metastable states that can
cause errors at the output.
REV 1A
Figure 1. Typical Interface Circuit Diagram
©2008 CADEKA Microcircuits LLC www.cadeka.com
6
Data Sheet
Typical Interface Circuit
There are two reference inputs and one external reference
voltage tap. These are -2V (VRB force and sense), midtap
(VRM) and AGND (VRT force and sense). The reference pins
and tap can be driven by op amps as shown in Figure 1 or
VRM may be bypassed for limited temperature operation.
These voltage inputs can be bypassed to AGND for further
noise suppression if so desired.
Table 1. Output Coding
VIN
VEE, AGND, DGND
VEE is the supply pin with AGND as ground for the device.
The power supply pins should be bypassed as close to the
device as possible with at least a 0.01μF ceramic capacitor.
A 10μF tantalum can also be used for low frequency
suppression. DGND is the ground for the ECL outputs and
is to be referenced to the output pulldown voltage and
appropriately bypassed as shown in Figure 1.
VIN (Analog Input)
CLK, CLK (Clock Inputs)
The clock inputs are designed to be driven differentially
with ECL levels. The duty cycle of the clock should be kept
at 50% to avoid causing larger second harmonics. If this is
not important to the intended application, then duty cycles
other than 50% may be used.
D0 To D8, DR, DR, (A and B)
The digital outputs can drive 50Ω to ECL levels when pulled
down to -2V. When pulled down to -5.2V, the outputs can
drive 130Ω to 1kΩ loads. All digital outputs are grey code
with the coding as shown in Table 1. Cadeka recommends
using differential receivers on the outputs of the data ready
lines to ensure the proper output rise and fall times.
©2008 CADEKA Microcircuits LLC D7–D0
> -0.5 LSB
1
10000000
-0.5 LSB
1
0
10000000
10000000
-1.5 LSB
0
0
10000000
10000001
•
•
•
•
•
•
0
0
11000000
01000000
•
•
•
•
•
•
-2.0V +0.5 LSB
0
0
00000001
00000000
< (-2.0V +0.5 LSB)
0
00000000
•
•
•
> -1.0V
•
•
•
REV 1A
There are two analog input pins that are tied to the same
point internally. Either one may be used as an analog input sense and the other for input force. This is convenient
for testing the source signal to see if there is sufficient
drive capability. The pins can also be tied together and
driven by the same source. The CDK1303 is superior to
similar devices due to a preamplifier stage before the comparators. This makes the device easier to drive because it
has constant capacitance and induces less slew rate distortion.
D8
Indicates the transition between the two codes
Thermal Management
The typical thermal impedance is as follows:
ΘCA = +17 °C/W in still air with no heat sink
We highly recommend that a heat sink be used for this
device with adequate air flow to ensure rated performance
of the device. We have found that a Thermalloy 17846
heat sink with a minimum air flow of 1 meter/second
(200 linear feet per minute) provides adequate thermal
performance under laboratory tests. Application specific
conditions should be taken into account to ensure that the
device is properly heat sinked.
www.cadeka.com
CDK1303 8-bit, 1 GSPS, Flash A/D Converter
The circuit in Figure 1 is intended to show the most elaborate
method of achieving the least error by correcting for integral
linearity, input induced distortion, and power supply/
ground noise. This is achieved by the use of external
reference ladder tap connections, input buffer, and supply
decoupling. Please contact the factory for the CDK1303
evaluation board application note that contains more details
on interfacing the CDK1303. The function of each pin
and external connections to other components is as follows:
VRBF, VRBS, VRTF, VRTS, VRM (Reference Inputs)
7
Data Sheet
Operation
N
VIN
N+5
N+1
1.0 ns
N+2
N+6
N+7
N+4
N+3
CLK
CLK
REV 1A
1.4 ns typ
DRA
DRA
Data Bank A
N-2
N+2
N
N+4
1.75 ns typ
DRB
DRB
Data Bank B
1.4 ns typ
N-1
N+1
N+3
1.75 ns typ
Figure 2. Timing Diagram
©2008 CADEKA Microcircuits LLC CDK1303 8-bit, 1 GSPS, Flash A/D Converter
The CDK1303 has 256 preamp/comparator pairs which are
each supplied with the voltage from VRT to VRB divided
equally by the resistive ladder as shown in the block
diagram. This voltage is applied to the positive input of
each preamplifier/comparator pair. An analog input voltage applied at VIN is connected to the negative inputs of
each preamplifier/comparator pair. The comparators are
then clocked through each one’s individual clock buffer.
When the CLK pin is in the low state, the master or input
stage of the comparators compare the analog input voltage to the respective reference voltage. When the CLK
pin changes from low to high the comparators are latched
to the state prior to the clock transition and output logic
codes in sequence from the top comparators, closest to
VRT (0V), down to the point where the magnitude of the
input signal changes sign (thermometer code). The output
of each comparator is then registered into four 64-to-6
bit decoders when the CLK is changed from high to low.
At the output of the decoders is a set of four 7-bit latches
which are enabled (“track”) when the clock changes from
high to low. From here, the output of the latches are
coded into 6 LSBs from 4 columns and 4 columns are coded
into 2 MSBs. Finally, 8 ECL output latches and buffers
are used to drive the external loads. The conversion
takes one clock cycle from the input to the data outputs.
www.cadeka.com
8
Data Sheet
Schematic Diagrams
Input Circuit
Output Circuit
Clock Circuit
MQUAD-80 Package
MQUAD-80
MILLIMETERS
MIN TYP
MAX
22.95
23.45
19.74
19.84
12.00
13.74
13.84
16.95
17.45
0.80
0.30
0.45
2.76
3.40
0.25
0.60
18.40
2.51
0°
7°
0.73
1.03
For additional information regarding our products, please visit CADEKA at: cadeka.com
CADEKA Headquarters Loveland, Colorado
T: 970.663.5452
T: 877.663.5452 (toll free)
CADEKA, the CADEKA logo design, COMLINEAR and the COMLINEAR logo design are trademarks or registered trademarks of CADEKA
Microcircuits LLC. All other brand and product names may be trademarks of their respective companies.
CADEKA reserves the right to make changes to any products and services herein at any time without notice. CADEKA does not assume any
responsibility or liability arising out of the application or use of any product or service described herein, except as expressly agreed to in
writing by CADEKA; nor does the purchase, lease, or use of a product or service from CADEKA convey a license under any patent rights,
copyrights, trademark rights, or any other of the intellectual property rights of CADEKA or of third parties.
Copyright ©2008 by CADEKA Microcircuits LLC. All rights reserved.
A m p l i fy t h e H u m a n E x p e r i e n c e
REV 1A
SYMBOL
A
B
C
D
E
F
G
H
I
J
K
L
M
INCHES
MIN
TYP MAX
0.904
0.923
0.777
0.781
0.472
0.541
0.545
0.667
0.687
0.031
0.012
0.018
0.109
0.134
0.010
0.024
0.724
0.099
0.110
0°
7°
0.029
0.041
CDK1303 8-bit, 1 GSPS, Flash A/D Converter
Mechanical Dimensions
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