CADEKA CDK2308BITQ64

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
CDK2308
Dual, 20/40/65/80MSPS, 10-bit
Analog-to-Digital Converters
n
10-bit resolution
n
20/40/65/80MSPS maximum sampling rate
n
Ultra-low power dissipation: 24/43/65/78mW
n
61.6dB SNR at 80MSPS and 8MHz FIN
n
Internal reference circuitry
n
1.8V core supply voltage
n
1.7V – 3.6V I/O supply voltage
n
Parallel CMOS output
64-pin QFN package
(TQFP-64 package option also available)
n
Dual channel
n
Pin compatible with CDK2307
APPLICATIONS
Several idle modes with fast startup times exist. Each channel can independently be powered down and the entire chip can either be put in Standby
Mode or Power Down mode. The different modes are optimized to allow the
user to select the mode resulting in the smallest possible energy consumption
during idle mode and startup.
The CDK2308 has a highly linear THA optimized for frequencies up to Nyquist.
The differential clock interface is optimized for low jitter clock sources and
supports LVDS, LVPECL, sine wave and CMOS clock inputs.
Functional Block Diagram
Medical Imaging
n
Portable Test Equipment
n
Digital Oscilloscopes
n
IF Communication
CLKP
n
CLKN
n
The CDK2308 is a high performance, low power dual Analog-to-Digital Converters (ADC). The ADC employs internal reference circuitry, a CMOS control
interface and CMOS output data, and is based on a proprietary structure.
Digital error correction is employed to ensure no missing codes in the complete full scale range.
CLK_EXT
10
10
Part Number
Speed
Package
Pb-Free
RoHS Compliant
Operating Temperature Range
Packaging Method
CDK2308AILP64
20MSPS
QFN-64
Yes
Yes
-40°C to +85°C
Tray
CDK2308BILP64
40MSPS
QFN-64
Yes
Yes
-40°C to +85°C
Tray
CDK2308CILP64
65MSPS
QFN-64
Yes
Yes
-40°C to +85°C
Tray
CDK2308DILP64
80MSPS
QFN-64
Yes
Yes
-40°C to +85°C
Tray
CDK2308AITQ64
20MSPS
TQFP-64
Yes
Yes
-40°C to +85°C
Tray
CDK2308BITQ64
40MSPS
TQFP-64
Yes
Yes
-40°C to +85°C
Tray
CDK2308CITQ64
65MSPS
TQFP-64
Yes
Yes
-40°C to +85°C
Tray
CDK2308DITQ64
80MSPS
TQFP-64
Yes
Yes
-40°C to +85°C
Tray
Moisture sensitivity level for all parts is MSL-2A. Preliminary
©2009 CADEKA Microcircuits LLC
www.cadeka.com
Rev 2B
Ordering Information
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
General Description
FEATURES
Data Sheet
Pin Configuration
D0_5
D0_4
D0_3
51
50
49
52
53
54
55
56
57
58
59
60
61
62
63
1
48
2
47
3
46
4
45
N/C
5
44
N/C
6
43
N/C
42
CLK_EXT
CDK2308
7
QFN-64,TQFP-64
8
41
32
31
30
29
28
CLK_EXT_EN
N/C
33
27
16
26
34
CLKN
N/C
15
N/C
35
CLKP
25
14
24
36
DVDDCLK
23
13
22
37
DVSSCLK
21
38
12
20
39
11
19
40
18
9
10
17
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
64
QFN-64, TQFP-64
Pin Assignments
Pin No.
Pin Name
1, 18, 23
DVDD
Description
Digital and I/O-ring pre driver supply voltage, 1.8V
CM_EXT
AVDD
Common Mode voltage output
Analog supply voltage, 1.8V
4, 5, 8
AVSS
Analog ground
6, 7
IP0, IN0
Analog input Channel 0 (non-inverting, inverting)
10, 11
IP1, IN1
Analog input Channel 1 (non-inverting, inverting)
13
DVSSCLK
Clock circuitry ground
14
DVDDCLK
Clock circuitry supply voltage, 1.8V
Rev 2B
2
3, 9, 12
15
CLKP
Clock input, non-inverting (Format: LVDS, PECL, CMOS/TTL, Sine Wave)
16
CLKN
Clock input, inverting. For CMOS input on CLKP, connect CLKN to ground
17, 64
DVSS
Digital circuitry ground
19
CLK_EXT_EN
CLK_EXT signal enabled when low (zero). Tristate when high.
20
DFRMT
Data format selection. 0: Offset Binary, 1: Two's Complement
21
PD_N
Full chip Power Down mode when Low. All digital outputs reset to zero. After chip power up,
always apply Power Down mode before using Active mode to reset chip.
22
OE_N_1
24, 41, 58
OVDD
I/O ring post-driver supply voltage. Voltage range 1.7V to 3.6V.
25, 40, 57
OVSS
Ground for I/O ring
©2009 CADEKA Microcircuits LLC
Output Enable Channel 1. Tristate when high
www.cadeka.com
2
Data Sheet
Pin Assignments (Continued)
Pin Name
Description
26
NC
No Connect
27
NC
No Connect
28
NC
No Connect
29
D1_0
Output Data Channel 1 (LSB)
30
D1_1
Output Data Channel 1
31
D1_2
Output Data Channel 1
32
D1_3
Output Data Channel 1
33
D1_4
Output Data Channel 1
34
D1_5
Output Data Channel 1
35
D1_6
Output Data Channel 1
36
D1_7
Output Data Channel 1
37
D1_8
Output Data Channel 1
38
D1_9
Output Data Channel 1 (MSB)
39
ORNG_1
Out of Range flag Channel 1. High when input signal is out of range
42
CLK_EXT
Output clock signal for data synchronization. CMOS levels.
43
NC
No Connect
44
NC
No Connect
45
NC
No Connect
46
D0_0
Output Data Channel 0
47
D0_1
Output Data Channel 0
48
D0_2
Output Data Channel 0
49
D0_3
Output Data Channel 0
50
D0_4
Output Data Channel 0
51
D0_5
Output Data Channel 0
52
D0_6
Output Data Channel 0
53
D0_7
Output Data Channel 0
54
D0_8
Output Data Channel 0
55
D0_9
Output Data Channel 0 (MSB)
56
ORNG_0
59
OE_N_0
CM_EXTBC_1,
CM_EXTBC_0
62, 63
SLP_N_1,
SLP_N_0
©2009 CADEKA Microcircuits LLC
Out of Range flag Channel 0. High when input signal is out of range.
Output Enable Channel 0. Tristate when low.
Bias control bits for the buffer driving pin CM_EXT
00: Off
01: 50uA
10: 500uA
11: 1mA
Sleep Mode
00: Sleep Mode
10: Channel 1 active
Rev 2B
60, 61
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
Pin No.
01: Channel 0 active
11: Both channels active
www.cadeka.com
3
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.
Min
Max
Unit
AVDD, AVSS
DVDD, DVSS
AVSS, DVSSCK, DVSS, OVSS
OVDD, OVSS
CKP, CKN, DVSSCK
Analog inputs and outpts (IPx, INx, AVSS)
Digital inputs
Digital outputs
-0.3
-0.3
-0.3
-0.3
-0.3
-0.3
-0.3
-0.3
+2.3
+2.3
+0.3
+3.9
+3.9
+2.3
+3.9
+3.9
V
V
V
V
V
V
V
V
Reliability Information
Parameter
Min
Storage Temperature Range
Lead Temperature (Soldering, 10s)
-60
Typ
Max
Unit
+150
°C
J-STD-020
ESD Protection
Product
TQFP-64, QFN-64
Human Body Model (HBM)
2kV
Recommended Operating Conditions
Parameter
Min
Operating Temperature Range
-40
Typ
Max
Unit
+85
°C
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
Parameter
Rev 2B
©2009 CADEKA Microcircuits LLC
www.cadeka.com
4
Data Sheet
Electrical Characteristics
(AVDD = 1.8V, DVDD = 1.8V, DVDDCLK = 1.8V, OVDD = 2.5V, 50MSPS clock, 50% clock duty cycle,
-1dBFS 8MHz input signal, 13-bit output, unless otherwise noted)
Symbol
Parameter
Conditions
Min
Typ
Max
Units
DC Accuracy
Offset Error
Guaranteed
Midscale offset
1
Gain Error
Full scale range deviation from typical
Gain Matching
Gain matching between channels
±0.05
Differential Non-Linearity
12-bit level
±0.15
ILE
Integral Non-Linearity
12-bit level
VCMO
Common Mode Voltage Output
DNL
-6
LSB
6
%FS
%FS
LSB
±0.2
LSB
VAVDD/2
V
Analog Input
VCMI
Input Common Mode
Analog input common mode voltage
VFSR
Full Scale Range
Differential input voltage range
VCM -0.1
2
VCM +0.2
Vpp
V
Input Capacitance
Differential input capacitance
2
pF
Bandwidth
Input bandwidth, full power
500
AVDD, DVDD
Core Supply Voltage
Supply voltage to all 1.8V domain pins.
See Pin Configuration and Description
1.7
1.8
2
V
2.5
3.6
V
I/O Supply Voltage
Output driver supply voltage (OVDD).
Must be higher than or equal to Core Supply
Voltage (VOVDD ≥ VOCVDD)
1.7
OVDD
MHz
Power Supply
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
No Missing Codes
Rev 2B
©2009 CADEKA Microcircuits LLC
www.cadeka.com
5
Data Sheet
Electrical Characteristics - CDK2308A
(AVDD = 1.8V, DVDD = 1.8V, DVDDCLK = 1.8V, OVDD = 2.5V, 20MSPS clock, 50% clock duty cycle,
-1dBFS 8MHz input signal, 13-bit output, unless otherwise noted)
Symbol
Parameter
Conditions
Min
Typ
Max
Units
61.7
dBFS
60
61.6
dBFS
FIN ≃ FS/2
61.6
dBFS
FIN = 20MHz
61.6
dBFS
FIN = 2MHz
61.7
dBFS
Performance
SNR
SNDR
Signal to Noise Ratio
Signal to Noise and Distortion Ratio
FIN = 8MHz
61.6
dBFS
FIN ≃ FS/2
60
60.5
dBFS
FIN = 20MHz
61.6
dBFS
80
dBc
81
dBc
70
dBc
FIN = 20MHz
80
dBc
FIN = 2MHz
-90
dBc
-90
dBc
FIN ≃ FS/2
-90
dBc
FIN = 20MHz
-90
dBc
FIN = 2MHz
-80
dBc
-81
dBc
FIN ≃ FS/2
-70
dBc
FIN = 20MHz
-80
dBc
FIN = 2MHz
10
bits
FIN = 2MHz
SFDR
HD2
HD3
ENOB
XTALK
Spurious Free Dynamic Range
Second order Harmonic Distortion
Third order Harmonic Distortion
Effective number of Bits
Crosstalk
FIN = 8MHz
70
FIN ≃ FS/2
FIN = 8MHz
FIN = 8MHz
FIN = 8MHz
-80
-70
9.9
bits
FIN ≃ FS/2
9.7
9.8
bits
FIN = 20MHz
9.9
bits
-105
dBc
Signal crosstalk between channels, FIN1 =
8MHz, FIN0 = 9.9MHz
Power Supply
AIDD
Analog Supply Current
DIDD
Digital Supply Current
OIDD
Output Driver Supply
8.2
mA
Digital core supply
1.7
mA
2.5V output driver supply, sine wave input,
FIN = 1MHz
2.8
mA
2.5V output driver supply, sine wave input,
FIN = 1MHz, CLK_EXT disabled
2.3
mA
14.8
mW
Digital Power Dissipation
OVDD = 2.5V, 5pF load on output bits,
FIN = 1MHz, CLK_EXT disabled
8.8
mW
Total Power Dissipation
OVDD = 2.5V, 5pF load on output bits,
FIN = 1MHz, CLK_EXT disabled
23.6
mW
9.9
µW
Sleep Mode 1
Power Dissipation, Sleep mode one channel
15.2
mW
Sleep Mode 2
Power Dissipation, Sleep mode both channels
7.7
mW
Power Down Dissipation
Rev 2B
Analog Power Dissipation
Clock Inputs
Max. Conversion Rate
Min. Conversion Rate
©2009 CADEKA Microcircuits LLC
20
MSPS
15
MSPS
www.cadeka.com
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
FIN = 2MHz
FIN = 8MHz
6
Data Sheet
Electrical Characteristics - CDK2308B
(AVDD = 1.8V, DVDD = 1.8V, DVDDCLK = 1.8V, OVDD = 2.5V, 40MSPS clock, 50% clock duty cycle,
-1dBFS 8MHz input signal, 13-bit output, unless otherwise noted)
Symbol
Parameter
Conditions
Min
Typ
Max
Units
Performance
SNR
SNDR
Signal to Noise Ratio
Signal to Noise and Distortion Ratio
61.6
dBFS
61.6
dBFS
FIN ≃ FS/2
61.6
dBFS
FIN = 30MHz
61.5
dBFS
FIN = 2MHz
61.6
dBFS
FIN = 8MHz
60
61.6
dBFS
FIN ≃ FS/2
60
61.2
dBFS
FIN = 30MHz
61.4
dBFS
80
dBc
81
dBc
72
dBc
FIN = 30MHz
80
dBc
FIN = 2MHz
-90
dBc
-90
dBc
FIN ≃ FS/2
-85
dBc
FIN = 30MHz
-85
dBc
FIN = 2MHz
-80
dBc
-81
dBc
FIN ≃ FS/2
-72
dBc
FIN = 30MHz
-80
dBc
FIN = 2MHz
9.9
bits
FIN = 2MHz
SFDR
HD2
HD3
ENOB
XTALK
Spurious Free Dynamic Range
Second order Harmonic Distortion
Third order Harmonic Distortion
Effective number of Bits
Crosstalk
FIN = 8MHz
70
FIN ≃ FS/2
FIN = 8MHz
FIN = 8MHz
FIN = 8MHz
-80
-70
9.9
bits
FIN ≃ FS/2
9.7
9.9
bits
FIN = 30MHz
9.9
bits
-100
dBc
Signal crosstalk between channels, FIN1 =
8MHz, FIN0 = 9.9MHz
Power Supply
AIDD
Analog Supply Current
DIDD
Digital Supply Current
OIDD
Output Driver Supply
14.4
mA
Digital core supply
3.4
mA
2.5V output driver supply, sine wave input,
FIN = 1MHz
5.1
mA
2.5V output driver supply, sine wave input,
FIN = 1MHz, CLK_EXT disabled
4.2
mA
25.9
mW
Digital Power Dissipation
OVDD = 2.5V, 5pF load on output bits,
FIN = 1MHz, CLK_EXT disabled
16.6
mW
Total Power Dissipation
OVDD = 2.5V, 5pF load on output bits,
FIN = 1MHz, CLK_EXT disabled
42.5
mW
9.7
µW
Sleep Mode 1
Power Dissipation, Sleep mode one channel
25.7
mW
Sleep Mode 2
Power Dissipation, Sleep mode both channels
11.3
mW
Power Down Dissipation
Rev 2B
Analog Power Dissipation
Clock Inputs
Max. Conversion Rate
Min. Conversion Rate
©2009 CADEKA Microcircuits LLC
40
MSPS
20
MSPS
www.cadeka.com
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
FIN = 2MHz
FIN = 8MHz
7
Data Sheet
Electrical Characteristics - CDK2308C
(AVDD = 1.8V, DVDD = 1.8V, DVDDCLK = 1.8V, OVDD=2.5V, 65MSPS clock, 50% clock duty cycle,
-1dBFS 8MHz input signal, 13-bit output, unless otherwise noted)
Symbol
Parameter
Conditions
Min
Typ
FIN = 8MHz
60
Max
Units
Performance
Signal to Noise Ratio
dBFS
61.6
dBFS
FIN ≃ FS/2
61.5
dBFS
FIN = 40MHz
61.3
dBFS
61.6
dBFS
FIN = 20MHz
61.6
dBFS
FIN ≃ FS/2
60.4
dBFS
FIN = 40MHz
61.1
dBFS
FIN = 8MHz
SNDR
Signal to Noise and Distortion Ratio
FIN = 8MHz
SFDR
Spurious Free Dynamic Range
60
77
dBc
FIN = 20MHz
70
77
dBc
FIN ≃ FS/2
70
dBc
FIN = 40MHz
75
dBc
-90
dBc
FIN = 20MHz
-95
dBc
FIN ≃ FS/2
-85
dBc
FIN = 40MHz
-90
dBc
-77
dBc
FIN = 20MHz
-77
dBc
FIN ≃ FS/2
-70
dBc
FIN = 40MHz
-75
dBc
9.9
bits
FIN = 20MHz
9.9
bits
FIN ≃ FS/2
9.7
bits
FIN = 40MHz
9.9
bits
Signal crosstalk between channels, FIN1 =
8MHz, FIN0 = 9.9MHz
-97
dBc
22
mA
Digital core supply
5.2
mA
2.5V output driver supply, sine wave input,
FIN = 1MHz
7.9
mA
2.5V output driver supply, sine wave input,
FIN = 1MHz, CLK_EXT disabled
6.4
mA
FIN = 8MHz
HD2
Second order Harmonic Distortion
FIN = 8MHz
HD3
Third order Harmonic Distortion
FIN = 8MHz
ENOB
XTALK
Effective number of Bits
Crosstalk
-80
-70
9.7
Power Supply
AIDD
Analog Supply Current
DIDD
Digital Supply Current
OIDD
Output Driver Supply
39.6
mW
Digital Power Dissipation
OVDD = 2.5V, 5pF load on output bits,
FIN = 1MHz, CLK_EXT disabled
25.4
mW
Total Power Dissipation
OVDD = 2.5V, 5pF load on output bits,
FIN = 1MHz, CLK_EXT disabled
65
mW
9.3
µW
Sleep Mode 1
Power Down Dissipation
Power Dissipation, Sleep mode one channel
38.2
mW
Sleep Mode 2
Power Dissipation, Sleep mode both channels
15.7
mW
Rev 2B
Analog Power Dissipation
Clock Inputs
Max. Conversion Rate
Min. Conversion Rate
©2009 CADEKA Microcircuits LLC
65
MSPS
40
MSPS
www.cadeka.com
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
SNR
61.6
FIN = 20MHz
8
Data Sheet
Electrical Characteristics - CDK2308D
(AVDD = 1.8V, DVDD = 1.8V, DVDDCLK = 1.8V, OVDD = 2.5V, 80MSPS clock, 50% clock duty cycle,
-1dBFS 8MHz input signal, 13-bit output, unless otherwise noted)
Symbol
Parameter
Conditions
Min
Typ
FIN = 8MHz
60
Max
Units
Performance
Signal to Noise Ratio
dBFS
61.2
dBFS
FIN = 30MHz
61.3
dBFS
FIN ≃ FS/2
61.3
dBFS
61.3
dBFS
FIN = 8MHz
SNDR
Signal to Noise and Distortion Ratio
FIN = 20MHz
60.7
dBFS
FIN = 30MHz
61
dBFS
FIN ≃ FS/2
59
dBFS
FIN = 8MHz
SFDR
Spurious Free Dynamic Range
60
75
dBc
FIN = 20MHz
70
75
dBc
FIN = 30MHz
75
dBc
FIN ≃ FS/2
65
dBc
-90
dBc
FIN = 20MHz
-95
dBc
FIN = 30MHz
-90
dBc
FIN ≃ FS/2
-80
dBc
-75
dBc
FIN = 20MHz
-75
dBc
FIN = 30MHz
-75
dBc
FIN ≃ FS/2
-65
dBc
9.9
bits
FIN = 20MHz
9.8
bits
FIN = 30MHz
9.8
bits
FIN ≃ FS/2
9.5
bits
Signal crosstalk between channels, FIN1 =
8MHz, FIN0 = 9.9MHz
-95
dBc
FIN = 8MHz
HD2
Second order Harmonic Distortion
FIN = 8MHz
HD3
Third order Harmonic Distortion
FIN = 8MHz
ENOB
XTALK
Effective number of Bits
Crosstalk
-80
-70
9.7
Power Supply
AIDD
Analog Supply Current
DIDD
Digital Supply Current
OIDD
Output Driver Supply
26.5
mA
Digital core supply
6.1
mA
2.5V output driver supply, sine wave input,
FIN = 1MHz
9.5
mA
2.5V output driver supply, sine wave input,
FIN = 1MHz, CLK_EXT disabled
7.6
mA
47.7
mW
Digital Power Dissipation
OVDD = 2.5V, 5pF load on output bits,
FIN = 1MHz, CLK_EXT disabled
30
mW
Total Power Dissipation
OVDD = 2.5V, 5pF load on output bits,
FIN = 1MHz, CLK_EXT disabled
77.7
mW
9.1
µW
Sleep Mode 1
Power Dissipation, Sleep mode one channel
46.1
mW
Sleep Mode 2
Power Dissipation, Sleep mode both channels
18.3
mW
Power Down Dissipation
Rev 2B
Analog Power Dissipation
Clock Inputs
Max. Conversion Rate
Min. Conversion Rate
©2009 CADEKA Microcircuits LLC
80
MSPS
65
MSPS
www.cadeka.com
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
SNR
61.6
FIN = 20MHz
9
Data Sheet
Digital and Timing Electrical Characteristics
(AVDD = 1.8V, DVDD = 1.8V, DVDDCLK = 1.8V, OVDD = 2.5V, 50 MSPS clock, 50% clock duty cycle,
-1 dBFS input signal, 5pF capacitive load, unless otherwise noted)
Symbol
Parameter
Conditions
Min
Typ
Max
Units
80
% high
Clock Inputs
20
Compliance
Input Range
CMOS, LVDS, LVPECL, Sine Wave
Differential input swing
400
Differential input swing, sine wave clock input
1.6
Input Common Mode Voltage
Keep voltages within ground and voltage of OVDD
Input Capacitance
Differential
TPD
Start Up Time Active Mode
From Power Down Mode to Active Mode
TSLP
Start Up Time Mode
From Sleep Mode to Active Mode
TOVR
Out Of Range Recovery Time
TAP
mVpp
Vpp
0.3
VOVDD -0.3
V
2
pF
Timing
900
clk cycles
20
clk cycles
1
clk cycles
Aperture Delay
0.8
ns
εRMS
Aperture Jitter
<0.5
ps
TLAT
Pipeline Delay
12
clk cycles
TD
Output Delay (see timing diagram)
5pF load on output bits
4
ns
TDC
Output Delay (see timing diagram)
Relative to CLK_EXT
2
ns
Logic Inputs
VIH
High Level Input Voltage
VIL
Low Level Input Voltage
IIH
VOVDD ≥ 3.0V
VOVDD = 1.7V – 3.0V
2
V
0.8 • VOVDD
V
VOVDD ≥ 3.0V
0
0.8
V
VOVDD = 1.7V – 3.0V
0
0.2 • VOVDD
V
High Level Input Leakage Current
-10
10
µA
IIL
Low Level Input Leakage Current
-10
10
µA
CI
Input Capacitance
3
pF
Logic Outputs
VOH
High Level Output Voltage
VOL
Low Level Output Voltage
CL
Max Capacitive Load
VOVDD-0.1
V
Post-driver supply voltage equal to pre-driver
supply voltage VOVDD = VOCVDD
Post-driver supply voltage above 2.25V (1)
0.1
V
5
pF
10
pF
Note:
(1) The outputs will be functional with higher loads. However, it is recommended to keep the load on output data bits as low as possible to keep dynamic currents
and resulting switching noise at a minimum.
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
Duty Cycle
Rev 2B
©2009 CADEKA Microcircuits LLC
www.cadeka.com
10
Data Sheet
+F1
+F4
+F
+F2
+F0
+
N-12
N-11
N-10
N-9
N-8
CLK_EXT
Figure 1. Timing Diagram
Recommended Usage
DC-Coupling
Analog Input
Figure 3 shows a recommended configuration for DCcoupling. Note that the common mode input voltage must
be controlled according to specified values. Preferably, the
CM_EXT output should be used as a reference to set the
common mode voltage.
The analog inputs to the CDK2308 is a switched capacitor
track-and-hold amplifier optimized for differential operation. Operation at common mode voltages at mid supply is recommended even if performance will be good for
the ranges specified. The CM_EXT pin provides a voltage
suitable as common mode voltage reference. The internal
buffer for the CM_EXT voltage can be switched off, and
driving capabilities can be changed by using the CM_EXTBC control input.
Ω
pF
Ω
Rev 2B
Figure 2 shows a simplified drawing of the input network.
The signal source must have sufficiently low output impedance to charge the sampling capacitors within one clock
cycle. A small external resistor (e.g. 22Ω) in series with
each input is recommended as it helps reducing transient
currents and dampens ringing behavior. A small differential
shunt capacitor at the chip side of the resistors may be
used to provide dynamic charging currents and may improve performance. The resistors form a low pass filter
with the capacitor, and values must therefore be determined by requirements for the application.
The input amplifier could be inside a companion chip or
it could be a dedicated amplifier. Several suitable single
ended to differential driver amplifiers exist in the market.
The system designer should make sure the specifications
of the selected amplifier is adequate for the total system,
and that driving capabilities comply with the CDK2308
input specifications.
Figure 3. DC-Coupled Input
Detailed configuration and usage instructions must be
found in the documentation of the selected driver.
AC-Coupling
Figure 2. Input Configuration
©2009 CADEKA Microcircuits LLC
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
N-13
N-13
A signal transformer or series capacitors can be used to
make an AC-coupled input network. Figure 4 shows a
recommended configuration using a transformer. Make
sure that a transformer with sufficient linearity is selected,
www.cadeka.com
11
Data Sheet
If the input signal is traveling a long physical distance
from the signal source to the transformer (for example a
long cable), kick-backs from the ADC will also travel along
this distance. If these kick-backs are not terminated properly at the source side, they are reflected and will add to
the input signal at the ADC input. This could reduce the
ADC performance. To avoid this effect, the source must
effectively terminate the ADC kick-backs, or the traveling
distance should be very short. If this problem could not be
avoided, the circuit in Figure 6 can be used.
Note that startup time from Sleep Mode and Power Down
Mode will be affected by this filter as the time required
to charge the series capacitors is dependent on the filter
cut-off frequency.
If the input signal has a long traveling distance, and the
kick-backs from the ADC not are effectively terminated
at the signal source, the input network of figure 8 can
be used. The configuration in figure 8 is designed to attenuate the kickback from the ADC and to provide an input impedance that looks as resistive as possible for frequencies below Nyquist. Values of the series inductor will
however depend on board design and conversion rate.
In some instances a shunt capacitor in parallel with the
termination resistor (e.g. 33pF) may improve ADC performance further. This capacitor attenuate the ADC kickback even more, and minimize the kicks traveling towards
the source. However, the impedance match seen into the
transformer becomes worse.
120nH 33Ω
1:1
33Ω
optional
RT
47Ω
RT
68Ω
220Ω
pF
120nH
33Ω
33Ω
Figure 4. Transformer-Coupled Input
Ω
pF
Ω
Figure 5. AC-Coupled Input
©2009 CADEKA Microcircuits LLC
Clock Input And Jitter Considerations
Typically high-speed ADCs use both clock edges to generate
internal timing signals. In the CDK2308 only the rising
edge of the clock is used. Hence, input clock duty cycles
between 20% and 80% is acceptable.
The input clock can be supplied in a variety of formats.
The clock pins are AC-coupled internally, and hence a wide
common mode voltage range is accepted. Differential
clock sources as LVDS, LVPECL or differential sine wave
can be connected directly to the input pins. For CMOS
inputs, the CLKN pin should be connected to ground, and
the CMOS clock signal should be connected to CLKP. For
differential sine wave clock input the amplitude must be
at least ±800mVpp.
www.cadeka.com
12
Rev 2B
Figure 5 shows AC-coupling using capacitors. Resistors
from the CM_EXT output, RCM, should be used to bias the
differential input signals to the correct voltage. The series
capacitor, CI, form the high-pass pole with these resistors,
and the values must therefore be determined based on
the requirement to the high-pass cut-off frequency.
Figure 6. Alternative Input Network
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
and that the bandwidth of the transformer is appropriate.
The bandwidth should exceed the sampling rate of the
ADC with at least a factor of 10. It is also important to
keep phase mismatch between the differential ADC inputs
small for good HD2 performance. This type of transformer
coupled input is the preferred configuration for high frequency signals as most differential amplifiers do not have
adequate performance at high frequencies. Magnetic
coupling between the transformers and PCB traces may
impact channel crosstalk, and must hence be taken into
account during PCB layout.
Data Sheet
The quality of the input clock is extremely important for
high-speed, high-resolution ADCs. The contribution to SNR
from clock jitter with a full scale signal at a given frequency
is shown in equation 1.
•
π • FIN • εt)
where FIN is the signal frequency, and εt is the total rms
jitter measured in seconds. The rms jitter is the total of all
jitter sources including the clock generation circuitry, clock
distribution and internal ADC circuitry.
For applications where jitter may limit the obtainable performance, it is of utmost importance to limit the clock jitter.
This can be obtained by using precise and stable clock references (e.g. crystal oscillators with good jitter specifications)
and make sure the clock distribution is well controlled. It
might be advantageous to use analog power and ground
planes to ensure low noise on the supplies to all circuitry
in the clock distribution. It is of utmost importance to avoid
crosstalk between the ADC output bits and the clock and
between the analog input signal and the clock since such
crosstalk often results in harmonic distortion.
The jitter performance is improved with reduced rise and
fall times of the input clock. Hence, optimum jitter performance is obtained with LVDS or LVPECL clock with fast
edges. CMOS and sine wave clock inputs will result in
slightly degraded jitter performance.
If the clock is generated by other circuitry, it should be
retimed with a low jitter master clock as the last operation
before it is applied to the ADC clock input.
Digital Outputs
The timing is described in the Timing Diagram section.
Note that the load or equivalent delay on CLK_EXT always
should be lower than the load on data outputs to ensure
sufficient timing margins.
The digital outputs can be set in tristate mode by setting
the OE_N signal high.
©2009 CADEKA Microcircuits LLC
The output data are presented on offset binary form
when DFRMT is low (connect to OVSS). Setting DFRMT
high (connect to OVDD) results in 2’s complement output
format. Details are shown in Table 1 on page 14.
Reference Voltages
The reference voltages are internally generated and buffered based on a bandgap voltage reference. No external
decoupling is necessary, and the reference voltages are
not available externally. This simplifies usage of the ADC
since two extremely sensitive pins, otherwise needed, are
removed from the interface.
Operational Modes
The operational modes are controlled with the PD_N and
SLP_N pins. If PD_N is set low, all other control pins are
overridden and the chip is set in Power Down mode. In this
mode all circuitry is completely turned off and the internal
clock is disabled. Hence, only leakage current contributes
to the Power Down Dissipation. The startup time from this
mode is longer than for other idle modes as all references
need to settle to their final values before normal operation
can resume.
The SLP_N bus can be used to power down each channel
independently, or to set the full chip in Sleep Mode. In this
mode internal clocking is disabled, but some low bandwidth circuitry is kept on to allow for a short startup time.
However, Sleep Mode represents a significant reduction in
supply current, and it can be used to save power even for
short idle periods.
The input clock should be kept running in all idle modes.
However, even lower power dissipation is possible in Power
Down mode if the input clock is stopped. In this case it is
important to start the input clock prior to enabling active mode.
www.cadeka.com
13
Rev 2B
Digital output data are presented on parallel CMOS form.
The voltage on the OVDD pin set the levels of the CMOS
outputs. The output drivers are dimensioned to drive
a wide range of loads for OVDD above 2.25V, but it is recommended to minimize the load to ensure as low transient switching currents and resulting noise as possible. In
applications with a large fanout or large capacitive loads,
it is recommended to add external buffers located close to
the ADC chip.
Data Format Selection
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
SNRjitter = 20 • log (2
The CDK2308 employs digital offset correction. This means
that the output code will be 4096 with the positive and
negative inputs shorted together(zero differential). However, small mismatches in parasitics at the input can cause
this to alter slightly. The offset correction also results in
possible loss of codes at the edges of the full scale range.
With “NO” offset correction, the ADC would clip in one
end before the other, in practice resulting in code loss at
the opposite end. With the output being centered digitally,
the output will clip, and the out of range flags will be set,
before max code is reached. When out of range flags are
set, the code is forced to all ones for over-range and all
zeros for under-range.
Data Sheet
Table 1: Data Format Description for 2Vpp Full Scale Range
Output Data: Dx_9 : Dx_0
(DFRMT = 0, offset binary)
(DFRMT = 1, 2’s complement)
1.0 V
11 1111 1111
01 1111 1111
+0.24mV
10 0000 0000
00 0000 0000
-0.24mV
01 1111 1111
11 1111 1111
-1.0V
00 0000 0000
10 0000 0000
Mechanical Dimensions
QFN-64 Package
aaa C A
A
ccc C
A
A2
A3
D
D1
aaa C B
A1
E
Symbol
A
A1
A2
A3
b
D
D1
D2
E
E1
E2
F
G
L
e
θ1
E1
aaa
bbb
ccc
Pin 1 ID
0.05 Dia.
Min
–
0.00
–
0.008
0.197
0.197
0.05
0.0096
0.012
0°
Inches
Millimeters
Typ
Max
Min
Typ
–
0.035
–
–
0.0004
0.002
0.00
0.01
0.026
0.028
–
0.65
0.008 REF
0.2 REF
0.010
0.012
0.2
0.25
0.354 BSC
9.00 BSC
0.354 BSC
8.75 BSC
0.205
0.213
5.0
5.2
0.354 BSC
9.00 BSC
0.344 BSC
8.75 BSC
0.205
0.213
5.0
5.2
–
–
1.3
–
0.0168
0.024
0.24
0.42
0.016
0.020
0.3
0.4
0.020 BSC
0.50 BSC
–
12°
0°
–
Tolerance of Form and Position
0.10
0.004
0.10
0.004
0.05
0.002
Max
0.9
0.05
0.7
0.30
5.4
5.4
–
0.6
0.5
12°
NOTES:
1. All dimensions are in millimeters.
2. Die thickness allowable is 0.305mm maximum (.012 inches maximum)
3. Dimensioning & tolerances conform to ASME y14.5m. -1994.
bbb C B
B
C
bbb C A
1.14
5. The pin #1 identifier must be placed on the top surface of the package by using indentation mark
or other feature of package body.
6. Exact shape and size of this feature is optional.
7. Package warpage max 0.08mm.
SIDE VIEW
9. Applied only to terminals.
10. Package corners unless otherwise specipied are r0.175±0.025mm.
F
D2
0.45
4. Dimension applies to plated terminal and is measured between 0.20 and 0.25mm from terminal tip.
8. Applied for exposed pad and terminals. Exclude embedding part of exposed pad from measuring.
TOP VIEW
Pin 1 ID
Dia. 0.20
seating
plane
θ1
1.14
G
Rev 2B
E2
L
e
b
0.10 M C A B
L
BOTTOM VIEW
©2009 CADEKA Microcircuits LLC
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
Output data: Dx_9 : Dx_0
Differential Input Voltage (IPx - INx)
www.cadeka.com
14
Data Sheet
Mechanical Dimensions (Continued)
TQFP-64 Package
TOP VIEW
SIDE VIEW
Min
–
0.002
0.037
0.003
0.003
0°
0°
11°
11°
0.004
0.018
0.008
0.007
Inches
Typ
–
–
0.039
0.472 BSC
0.393 BSC
0.472 BSC
0.393 BSC
–
–
3.5°
–
12°
12°
–
0.24
0.039 REF
–
0.008
0.020 BSC
0.295
0.295
0.008
0.008
0.003
0.003
Max
0.047
0.006
0.041
Min
–
0.05
0.95
0.008
–
7°
–
13°
13°
0.008
0.030
0.08
0.08
0°
0°
11°
11°
0.09
0.45
–
0.011
0.20
0.17
Millimeters
Typ
–
–
1.00
12.00 BSC
10.00 BSC
12.00 BSC
10.00 BSC
–
–
3.5°
–
12°
12°
0.20
0.75
1.00 REF
–
0.20
0.520 BSC
7.50
7.50
0.20
0.20
0.08
0.08
Max
1.2
0.15
1.05
0.20
–
7°
–
13°
13°
–
0.27
NOTES:
1. Dimensions D1 and E1 do not include mold protrusion. Allowable protrusion is
0.25mm per side. D1 and E1 are maxmum plastic body size dimensions
including mold mismatch.
2. Dimension b does not include dambar protrusion. Allowable dambar protrusion
shall not cause the lead width to exceed the maximum b dimension by more
than 0.08mm.
3. Dambar can not be located on the lower radius or the foot. Minimum space
between protrusion and an adjacent lead is 0.07mm for 0.4mm and 0.5mm
pitch packages.
DETAIL SIDE VIEW
CDK2308 Dual, 20/40/65/80MSPS, 10-bit Analog-to-Digital Converters
Symbol
A
A1
A2
D
D1
E
E1
R2
R1
θ
θ1
θ2
θ3
c
L
L1
S
b
e
D2
E2
aaa
bbb
ccc
ddd
Rev 2B
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 ©2009 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