®
®
ADS-CCD1202
12-Bit, 2MHz, Sampling A/D’s
for CCD Imaging Applications
IN N O VA T IO N a n d E X C E L L E N C E
FEATURES
•
•
•
•
•
•
•
•
•
•
Unipolar input range (0 to +10V)
2MHz sampling rate
4096-to-1 dynamic range (72.2dB)
Low noise, 600µVrms (1/4 of an LSB)
Outstanding differential nonlinearity error (±0.45 LSB max.)
Small, 24-pin ceramic DDIP
Low power, 1.75 Watts
Operates from ±12V or ±15V supplies
Edge-triggered, no pipeline delay
Low cost
GENERAL DESCRIPTION
The functionally complete, easy-to-use ADS-CCD1202 is a
12-bit, 2MHz Sampling A/D Converter whose performance
and production testing have been optimized for use in CCD
applications. This device delivers the lowest noise (600µVrms)
and the best differential linearity error (±0.45LSB maximum) of
any commercially available 12-bit A/D in its speed class. It can
respond to full scale input steps (from empty to full well) with
less than a single count of error, and its input is immune to
overvoltages that may occur due to blooming.
Packaged in an industry-standard, 24-pin, ceramic DDIP, the
ADS-CCD1202 requires ±15V (or ±12V) and +5V supplies and
typically consumes 1.75 (1.45) Watts. The device is 100%
production tested for all critical performance parameters and is
fully specified over both the 0 to +70°C and –55 to +125°C
operating temperature ranges.
For those applications using correlated double sampling, the
ADS-CCD1202 can be supplied without its internal sample-
hold amplifier and achieve conversion rates up to 2.5MHz.
PIN
1
2
3
4
5
6
7
8
9
10
11
12
INPUT/OUTPUT CONNECTIONS
FUNCTION
BIT 12 (LSB)
BIT 11
BIT 10
BIT 9
BIT 8
BIT7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1 (MSB)
PIN
24
23
22
21
20
19
18
17
16
15
14
13
FUNCTION
–12V/–15V SUPPLY
GROUND
+12V/+15V SUPPLY
+10V REFERENCE OUT
ANALOG INPUT
GROUND
NO CONNECT
NO CONNECT
START CONVERT
EOC
GROUND
+5V SUPPLY
DATEL will also entertain discussions about including the CDS
circuit internal to the ADS-CCD1202. Contact us for details.
–
ANALOG INPUT 20
S/H
+
S1
S2
DAC
12 BIT 1 (MSB)
11 BIT 2
+10V REFERENCE 21
REF
10 BIT 3
9
8
REGISTER
DIGITAL
CORRECTION
LOGIC
7
6
5
FLASH
ADC
BUFFER
REGISTER
4
3
2
1
BIT 4
BIT 5
BIT 6
BIT 7
BIT 8
BIT 9
BIT 10
BIT 11
BIT 12 (LSB)
START CONVERT 16
EOC 15
TIMING AND
CONTROL LOGIC
13
+5V SUPPLY
17, 18
NO CONNECT
22
+12V/+15V SUPPLY
14, 19, 23
GROUND
24
–12V/–15V SUPPLY
Figure 1. ADS-CCD1202 Functional Block Diagram
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 (U.S.A.)
•
Tel: (508) 339-3000 Fax: (508)339-6356
•
For immediate assistance: (800) 233-2765
®
®
ADS-CCD1202
ABSOLUTE MAXIMUM RATINGS
PARAMETERS
+12V/+15V Supply
(Pin 22)
–12V/–15V Supply
(Pin 24)
+5V Supply
(Pin 13)
Digital Input
(Pin 16)
Analog Input
(Pin 20)
Lead Temp.
(10 seconds)
LIMITS
0 to +16
0 to –16
0 to +6
–0.3 to +V
DD
+0.3
–5 to +14
+300
UNITS
Volts
Volts
Volts
Volts
Volts
°C
PHYSICAL/ENVIRONMENTAL
PARAMETERS
Operating Temp. Range, Case
ADS-CCD1202MC
ADS-CCD1202MM
Thermal Impedance
θ
jc
θ
ca
Storage Temperature Range
Package Type
Weight
MIN.
0
–55
TYP.
—
—
MAX.
+70
+125
UNITS
°C
°C
—
5
—
°C/Watt
—
24
—
°C/Watt
–65
–
+150
°C
24-pin, metal-sealed ceramic DDIP
0.42 ounces (12 grams)
FUNCTIONAL SPECIFICATIONS
(T
A
= +25°C, ±Vcc = ±15V (or ±12V), +V
DD
= +5V, 1.2MHz sampling rate, and a minimum 1 minute warmup unless otherwise specified.)
+25°C
ANALOG INPUT
Input Voltage Range
Input Resistance
Input Capacitance
DIGITAL INPUTS
Logic Levels
Logic "1"
Logic "0"
Logic Loading "1"
Logic Loading "0"
Start Convert Positive Pulse Width
STATIC PERFORMANCE
Resolution
Integral Nonlinearity
(fin = 10kHz)
Differential Nonlinearity
(fin = 10kHz)
Full Scale Absolute Accuracy
Offset Error
(Tech Note 2)
Gain Error
(Tech Note 2)
No Missing Codes
(fin = 10kHz)
DYNAMIC PERFORMANCE
Peak Harmonics
(–0.5dB)
dc to 500kHz
500kHz to 1MHz
Total Harmonic Distortion
(–0.5dB)
dc to 500kHz
500kHz to 1MHz
Signal-to-Noise Ratio
(w/o distortion, –0.5dB)
dc to 500kHz
500kHz to 1MHz
Signal-to-Noise Ratio
(8 distortion, –0.5dB)
dc to 500kHz
500kHz to 1MHz
Two-tone Intermodulation Distortion
(fin = 200kHz, 500kHz
fs = 2MHz, –0.5dB)
Noise
Input Bandwidth
(–3dB)
Small Signal (–20dB input)
Large Signal(–0.5dB input)
Feedthrough Rejection
(fin = 1MHz)
Slew Rate
Aperture Delay Time
Aperture Uncertainty
S/H Acquisition Time
( to ±0.01%FSR, 10V step)
Overvoltage Recovery Time
A/D Conversion Rate
—
—
—
—
71
71
70
68
—
—
—
—
—
—
—
—
150
—
2
–80
–77
–76
–75
72
72
71
71
–83
600
9
8
82
±200
±20
5
190
400
—
–75
–71
–73
–70
—
—
—
—
—
—
—
—
—
—
—
—
230
500
—
—
—
—
—
71
71
70
68
—
—
—
—
—
—
—
—
150
—
2
–80
–77
–76
–75
72
72
71
71
–82
600
9
8
82
±200
±20
5
190
400
—
–75
–71
–73
–70
—
—
—
—
—
—
—
—
—
—
—
—
230
500
—
—
—
—
—
71
70
68
65
—
—
—
—
—
—
—
—
150
—
2
–76
–73
–74
–71
72
72
70
69
–81
600
9
8
82
±200
±20
5
190
400
—
–72
–66
–70
–65
—
—
—
—
—
—
—
—
—
—
—
—
230
500
—
dB
dB
dB
dB
dB
dB
dB
dB
dB
µVrms
MHz
MHz
dB
V/µs
ns
ps rms
ns
ns
MHz
—
—
—
—
—
—
12
12
±0.5
+0.25
+0.1
±0.15
±0.1
—
—
—
±0.45
±0.3
±0.3
±0.4
—
—
—
—
—
—
—
12
12
±0.5
±0.25
±0.2
±0.2
±0.4
—
—
—
±0.45
±0.5
±0.5
±0.8
—
—
—
—
—
—
—
12
12
±1
±0.35
±0.3
±0.5
±0.5
—
—
—
±0.75
±0.8
±1.2
±1.4
—
Bits
LSB
LSB
%FSR
%FSR
%
Bits
+2
—
—
—
—
—
—
—
—
200
—
+0.8
+20
–20
—
+2
—
—
—
—
—
—
—
—
200
—
+0.8
+20
–20
—
+2
—
—
—
—
—
—
—
—
200
—
+0.8
+20
–20
—
Volts
Volts
µA
µA
ns
MIN.
—
0.99
—
TYP.
0 to +10
1
7
MAX.
—
1.01
15
MIN.
—
0.99
—
0 to +70°C
TYP.
0 to +10
1
7
MAX.
—
1.01
15
MIN.
—
0.99
—
–55 to +125° C
TYP.
0 to +10
1
7
MAX.
—
1.01
15
UNITS
Volts
kΩ
pF
2.
®
®
ADS-CCD1202
+25°C
ANALOG OUTPUT
Internal Reference
Voltage
Drift
External Current
DIGITAL OUTPUTS
Logic Levels
Logic "1"
Logic "0"
Logic Loading “1"
Logic Loading "0"
Delay, Falling Edge of EOC
to Output Data Valid
Output Coding
POWER REQUIREMENTS, ±15V
Power Supply Range
+15V Supply
–15V Supply
+5V Supply
Power Supply Current
+15V Supply
–15V Supply
+5V Supply
Power Dissipation
Power Supply Rejection
POWER REQUIREMENTS, ±12V
Power Supply Range
+12V Supply
–12V Supply
+5V Supply
Power Supply Current
+12V Supply
–12V Supply
+5V Supply
Power Dissipation
Power Supply Rejection
+11.5
–11.5
+4.75
—
—
—
—
—
+12.0
–12.0
+5.0
+43
–48
+82
1.45
—
+12.5
–12.5
+5.25
+55
–55
+95
1.65
±0.01
+11.5
–11.5
+4.75
—
—
—
—
—
+12.0
–12.0
+5.0
+43
–48
+82
1.45
—
+12.5
–12.5
+5.25
+55
–55
+95
1.65
±0.01
+11.5
–11.5
+4.75
—
—
—
—
—
+12.0
–12.0
+5.0
+43
–48
+82
1.45
—
+12.5
–12.5
+5.25
+55
–55
+95
1.65
±0.01
Volts
Volts
Volts
mA
mA
mA
Watts
%FSR/%V
+14.5
–14.5
+4.75
—
—
—
—
—
+15.0
–15.0
+5.0
+43
–48
+82
1.75
—
+15.5
–15.5
+5.25
+55
–55
+95
1.95
±0.01
+14.5
–14.5
+4.75
—
—
—
—
—
+15.0
–15.0
+5.0
+43
–48
+82
1.75
—
+15.5
–15.5
+5.25
+55
–55
+95
1.95
±0.01
+14.5
–14.5
+4.75
—
—
—
—
—
+15.0
–15.0
+5.0
+43
–48
+82
1.75
—
+15.5
–15.5
+5.25
+55
–55
+95
1.95
±0.01
Volts
Volts
Volts
mA
mA
mA
Watts
%FSR/%V
+2.4
—
—
—
—
—
—
—
—
—
—
+0.4
–4
+4
35
+2.4
—
—
—
—
—
—
—
—
—
Straight Binary
—
+0.4
–4
+4
35
+2.4
—
—
—
—
—
—
—
—
—
—
+0.4
–4
+4
35
Volts
Volts
mA
mA
ns
MIN.
+9.95
—
—
TYP.
+10.0
±5
—
MAX.
+10.05
—
1.5
MIN.
+9.95
—
—
0 to +70°C
TYP.
+10.0
±5
—
MAX.
+10.05
—
1.5
MIN.
+9.95
—
—
–55 to +125°C
TYP.
+10.0
±5
—
MAX.
+10.05
—
1.5
UNITS
Volts
ppm/ºC
mA
Footnotes:
All power supplies must be on before applying a start convert pulse. All
supplies and the clock (START CONVERT) must be present during warmup
periods. The device must be continuously converting during this time.
Contact DATEL for availability of other input voltage ranges.
A 200ns wide start convert pulse is used for all production testing.
Effective bits is equal to:
(SNR + Distortion) – 1.76 +
20 log
6.02
Full Scale Amplitude
Actual Input Amplitude
This is the time required before the A/D output data is valid after
the analog input is back within the specified range.
TECHNICAL NOTES
1. Obtaining fully specified performance from the ADS-CCD1202
requires careful attention to pc-card layout and power supply
decoupling. The device’s analog and digital ground systems are
connected to each other internally. For optimal performance, tie
all ground pins (14, 19, and 23) directly to a large
analog
ground plane beneath the package.
Bypass all power supplies, as well as the REFERENCE
OUTPUT (pin 21), to ground with 4.7µF tantalum capacitors in
parallel with 0.1µF ceramic capacitors. Locate the bypass
capacitors as close to the unit as possible. If the user-installed
offset and gain adjusting circuit shown in Figure 2 is used, also
locate it as close to the ADS-CCD1202 as possible.
2. ADS-CCD1202 achieves its specified accuracies without
external calibration. If required, the device’s small initial offset
and gain errors can be reduced to zero using the input circuit of
Figure 2. When using this circuit, or any similar offset and gain-
calibration hardware, make adjustments following warmup. To
avoid interaction, always adjust offset before gain.
3. When operating the ADS-CCD1202 from ±12V supplies, do not
drive external circuitry with the REFERENCE OUTPUT (pin 21).
The reference’s accuracy and drift specifications may not be
met, and loading the circuit may cause accuracy errors within
the converter.
4. A passive bandpass filter is used at the input of the A/D for all
production testing.
5. Applying a start pulse while a conversion is in progress (EOC =
logic "1") initiates a new and inaccurate conversion cycle. Data
for the interrupted and subsequent conversions will be invalid.
Table 1. Zero and Gain Adjust
Input Voltage
Range
0 to +10V
Zero Adjust
+1/2 LSB
+1.2207mV
Gain Adjust
+FS – 1 1/2 LSB
+9.99634V
3.
®
®
ADS-CCD1202
CALIBRATION PROCEDURE
(Refer to Figures 2 and 3)
Any offset and/or gain calibration procedures should not be
implemented until devices are fully warmed up. To avoid
interaction, offset must be adjusted before gain. The ranges of
adjustment for the circuit of Figure 2 are guaranteed to
compensate for the ADS-CCD1202’s initial accuracy errors and
may not be able to compensate for additional system errors.
+15V
ZERO/
OFFSET
ADJUST
–15V
20k
Ω
200k
Ω
2k
Ω
For the ADS-CCD1202, offset adjusting is normally
accomplished at the point where all output bits are 0’s and the
LSB just changes from a 0 to a 1. This digital output transition
ideally occurs when the applied analog input is +1/2LSB
(+1.2207mV).
Gain adjusting is accomplished when all bits are 1’s and the
LSB just changes from a 1 to a 0. This transition ideally occurs
when the analog input is at +full scale minus 1 1/2 LSB’s
(+9.99634V).
Offset Adjust Procedure
1. Apply a train of pulses to the START CONVERT input (pin
16) so the converter is continuously converting. If using
LED’s on the outputs, a 200kHz conversion rate will reduce
flicker.
GAIN
ADJUST
+15V
1.98k
Ω
50
Ω
To Pin 20 of
ADS-CCD1202
SIGNAL
INPUT
2. Apply +1.2207mV to the ANALOG INPUT (pin 20).
3. Adjust the offset potentiometer until the output bits are
0000 0000 00000 and the LSB flickers between 0 and 1.
Gain Adjust Procedure
1. Apply +9.99634V to the ANALOG INPUT (pin 20).
2. Adjust the gain potentiometer until all output bits are 1’s and
the LSB flickers between 1 and 0.
Table 2. ADS-CCD1202 Output Coding
–15V
Figure 2. ADS-CCD1202 Calibration Circuit
All fixed resistors in Figure 2 should be metal-film types, and
multi-turn potentiometers should have TCR’s of 100ppm/°C or
less to minimize drift with temperature. In many applications,
the CCD will require an offset-adjust (black balance) circuit
near its output and also a gain stage, presumably with adjust
capabilities, to match the output voltage of the CCD to the
input range of the AID. If one is performing a "system I/O
calibration" (from light in to digital out), these circuits can be
used to compensate for the relatively small initial offset and
gain errors of the A/D. This would eliminate the need for the
circuit shown in Figure 2.
Input Voltage
(0 to +10V)
+9.9976
+7.5000
+5.0000
+2.5000
+0.0024
0
Unipolar
Scale
+FS – 1LSB
+3/4 FS
+1/2 FS
+1/4 FS
+1LSB
0
Digital Output
MSB LSB
1111 1111 1111
1100 0000 0000
1000 0000 0000
0100 0000 0000
0000 0000 0001
0000 0000 0000
+5V
4.7µF
+
0.1µF
13
12 BIT 1 (MSB)
11 BIT 2
10 BIT 3
9 BIT 4
THERMAL REQUIREMENTS
All DATEL sampling A/D converters are fully characterized and
specified over operating temperature (case) ranges of 0 to
+70°C and – 55 to +125°C. All room-temperature (T
A
= +25°C)
production testing is performed without the use of heat sinks or
forced-air cooling. Thermal impedance figures for each device
are listed in their respective specification tables.
These devices do not normally require heat sinks, however,
standard precautionary design and layout procedures should
be used to ensure devices do not overheat. The ground and
power planes beneath the package, as well as all pcb signal
runs to and from the device, should be as heavy as possible to
help conduct heat away from the package. Electrically
insulating, thermally-conductive "pads" may be installed
underneath the package. Devices should be soldered to boards
rather than "socketed," and of course, minimal air flow over the
surface can greatly help reduce the package temperature.
In more severe ambient conditions, the package/junction
temperature of a given device can be reduced dramatically
(typically 35%) by using one of DATEL’s HS Series heat sinks.
See Ordering Information for the assigned part number. See
page 1-183 of the DATEL Data Acquisition Components
Catalog for more information on the HS Series. Request DATEL
Application Note AN-8, "Heat Sinks for DIP Data Converters,"or
contact DATEL directly, for additional information.
14
–12V/–15V
4.7µF
+
4.7µF
+12V/+15V
0.1µF
24
8 BIT 5
19, 23
0.1µF
22
0 to +10V
ADS-CCD1202
7 BIT 6
6 BIT 7
5 BIT 8
4 BIT 9
+
ANALOG
20 INPUT
21 +10V REF. OUT
3 BIT 10
2 BIT 11
1 BIT 12 (LSB)
0.1µF
+
4.7µF
17, 18
NO CONNECT
15 EOC
Figure 3. Typical ADS-CCD1202 Connection Diagram
A/D converters are calibrated by positioning their digital
outputs exactly on the transition point between two adjacent
digital output codes. This can be accomplished by connecting
LED’s to the digital outputs and adjusting until certain LED’s
"flicker" equally between on and off. Other approaches employ
digital comparators or microcontrollers to detect when the
outputs change from one code to the next.
4.
®
®
ADS-CCD1202
N
START
CONVERT
200ns typ.
N+1
10ns typ.
INTERNAL S/H
310ns typ.
Hold
Acquisition Time
190ns typ.
70ns ±10ns
30ns typ.
EOC
Conversion Time
360ns ±20ns
35ns max.
75ns max.
OUTPUT DATA
DATA (N-1) VALID
425ns min.
INVALID
DATA
DATA N VALID
Note: Scale is approximately 25ns per division.
Figure 4. ADS-CCD1202 Timing Diagram
TIMING
The ADSCCD-1202 is an edge triggered device. A conversion
is initiated by the rising edge of the start convert pulse and no
additional external timing signals are required. The device does
not employ "pipeline" delays to increase its throughput rate. It
does not require multiple start convert pulses to bring valid
digital data to its output pins.
+15V
R3
200K 5%
C1
0.1MF
C2
15pF COG
R5
2K .1%
12
13
+15V
U4
74LS86
2
4
6
6
AD845
4
C6
2.2MF
-15V
R8
10K
0.1%
13
14
3
+
16
C23
0.1MF
17
18
19
C10
0.1MF
-15V
+15V
C11
2.2MF
C9
2.2MF
20
21
15
ADS-CCD1201/1202
+5V
DGND
EOC
ST. CONV
B2
B1
AGND
INPUT
U1
B3
B4
B5
B6
B7
B8
B9
B10
B11
B12
B13
B14
3
2
1
12
11
10
9
8
7
6
5
4
U3
74LS240
2
4
6
8
11
13
15
17
19
1A1
1A2
1A3
1A4
2A1
2A2
2A3
2A4
2G
C7
0.1MF
C8
2.2MF
+5V
8
11
13
C21
0.1MF
R7
10K 0.1%
C5
0.1MF
11
+5V
U2
74LS240
R4
1.98K
0.1%
R6
2K 0.1%
3
+
C4
2.2MF
2
7
–
U5
20
1Y1
1Y2
1Y3
1Y4
2Y1
2Y2
2Y3
2Y4
1G
10
+5V
C17
0.1MF
P2
18
16
14
12
9
7
5
3
1
B1
B2
B3
B4
B5
B6
B7
SG3
C16
0.1MF
SG2
32
30
33
31
OFFSET
ADJ
R2
20K
-15V
+
P4
ANALOG
INPUT
R1
50
C3
0.1MF
1A1
1A2
1A3
1A4
2A1
2A2
2A3
2A4
2G
28 MSB 29
26
24
22
20
27
25
23
21
19
GAIN
ADJ
+
J5
+15V
15
17
19
C19
2.2MF
+
C20
0.1MF
7
6
OP-77
4
U6
–
2
P1
+5V
2
4
6
8
10
1
3
5
7
9
C22
2.2
-15V MF
+
20
1Y1
1Y2
1Y3
1Y4
2Y1
2Y2
2Y3
2Y4
1G
10
18
16
14
12
9
7
5
3
1
B8
B9
B10
B11
B12
B13
B14
18
16
14
12
10
8
6
17
15
13
11
9
7
LSB 5
+
+
12 11
14 13
16 15
18 17
20 19
22 21
24 23
25
26
START
CONVERT
+15V
C12
0.1MF
-15V
C13
0.1MF
+5V
C15
0.1MF
C14
2.2MF
+10VREF
22 +15V
23
AGND
24 -15V
+
4 EOC 3
2
ST.CONV.
1
+
34 ENABLE
4
5
U4
74LS86
6
J3
9
10
U4
74LS86
NOTES:
1. FOR ADS-BCCD1201 Y1 IS 1.2MHZ
FOR ADS-BCCD1201 Y1 IS 2MHZ
8
J4
P3
J1
J2
14
1
2
C24
U4
7
3
74LS86
SG1
1
SEE NOTE 1
7
Y1
14
XTAL
8
+5V
+
2.2MF
C18
0.1MF
Figure 5.
ADS-CCD1202 Evaluation Board Schematic
5.
stm32/stm8
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