ADS-928

ADS-928
500kHz, 14-Bit Sampling A/D Converters
PRODUCT OVERVIEW
DATEL's ADS-928 is a 14-bit, 500kHz sampling rate, functionally complete AID converter. The ADS-928
samples up to Nyquist with no missing codes. Packaged in a small 32-pin DIP, power requirements are
±15V and +5V with 3.4 Watts power dissipation. Please contact DATEL for availability.
FEATURES
„ 4-bit resolution
„ 500kHz sampling rate
„ Functionally complete
„ Small 32-pin DIP
„ Low-power, 3.1 Watts
„ Excellent dynamic performance
„ Samples up to Nyquist
INPUT/OUTPUT CONNECTIONS
PIN FUNCTION
PIN
FUNCTION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
+10V REF. OUT
BIPOLAR
ANALOG INPUT
SIGNAL GROUND
OFFSET ADJUST
GAIN ADJUST
OVERFLOW
COMP BIN
ENABLE
+5V SUPPLY
DIGITAL GROUND
+15V SUPPLY
-15V SUPPLY
NO CONNECTION
ANALOG GROUND
EOC
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
BIT 14 OUT (LSB)
BIT 13 OUT
BIT 12 OUT
BIT 11
BIT 10 OUT
BIT 9 OUT
BIT 8 OUT
BIT 7 OUT
BIT 6 OUT
BIT 5 OUT
BIT4 OUT
BIT 3 OUT
BIT 2 OUT
BIT 1 OUT (MSB)
BIT 1 OUT (MSB)
START CONVERT
BLOCK DIAGRAM
+
DAC
–
GAIN ADJUST 6
REF
+10V REF. OUT 1
31 BIT 1 OUT (MSB)
30 BIT 1 OUT (MSB)
S2
BIPOLAR 2
ANALOG INPUT
3
FLASH
ADC
BUFFER
S1
REGISTER
29 BIT 2 OUT
OFFSET
CIRCUIT
OFFSET ADJUST 5
28 BIT 3 OUT
27 BIT 4 OUT
26 BIT 5 OUT
DIGITAL
CORRECTION
LOGIC
S/H
3-STATE
OUTPUT
REGISTER
25 BIT 6 OUT
24 BIT 7 OUT
23 BIT 8 OUT
22 BIT 9 OUT
REGISTER
LOGIC
CONTROL
AND
TIMING
START CONVERT 32
21 BIT 10 OUT
20 BIT 11 OUT
19 BIT 12 OUT
18 BIT 13 OUT
17 BIT 14 OUT (LSB)
9 ENABLE
EOC 16
7 OVERFLOW
4
10
11
12
15
13
8
SIGNAL
GROUND
+5V
SUPPLY
DIGITAL
GROUND
+15V
SUPPLY
ANALOG
GROUND
-15V
SUPPLY
COMP BIN
Figure 1. ADS-928 Functional Block Diagram
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA
• Tel: (508) 339-3000
•
www.datel.com
•
e-mail: [email protected]
27 Jul 2015
MDA_ADS-928.B02 Page 1 of 4
ADS-928
500kHz, 14-Bit Sampling A/D Converters
PARAMETERS
+15V Supply (Pin 12)
–15V Supply (Pin 13)
+5V Supply (Pin 10)
Digital Inputs (Pins 9, 32)
Analog Input (Pin 3)
Lead Temp. (10 seconds)
ABSOLUTE MAXIMUM RATINGS
LIMITS
0 to +16
0 to –16
0 to +6
–0.3 to +7.0
-7.5 to +12.5
300 max.
OUTPUTS
UNITS
Volts
Volts
Volts
Volts
Volts
°C
FUNCTIONAL SPECIFICATIONS
(TA = +25°C, ±VCC = +15V, +VDD =+5V, 500kHz sampling rate, and a 5 minute
warmup unless otherwise specified.)
ANALOG INPUTS
Input Voltage Range
MIN.
TYP.
MAX.
UNITS
Input Impedence
Input Capacitance
—
—
4.9
—
0 to +10
±5
5
7
—
—
—
15
Volts
Volts
kΩ
pF
DIGITAL INPUTS
Logic Levels
Logic "1"
Logic "0"
Logic Loading "1"
Logic Loading "0"
+2.0
—
—
—
—
—
—
—
—
+0.8
+20
–20
Volts
Volts
μA
μA
PERFORMANCE
Integral Non-Linearity @ fin = 10kHz
+25°C
—
±1/2
±2
LSB
0 to +70°C
—
±1
±2
LSB
–55 to +125°C
—
±1
±3
LSB
Differential Non-Linearity @ fin = 10kHz
+25°C
—
±1/2
±0.85
LSB
0 to +70°C
—
±1/2
±0.95
LSB
–55 to +125°C
—
±3/4
±2
LSB
Full Scale Absolute Accuracy
+25°C
—
±0.08
±0.3
%FSR
0 to +70°C
—
±0.2
±0.6
%FSR
–55 to +125°C
—
±0.4
±0.8
%FSR
Unipolar Zero Error
+25°C
—
±0.1
±0.15
%FSR
0 to +70°C
—
±0.1
±0.2
%FSR
–55 to +125°C
—
±0.2
±0.3
%FSR
Bipolar Zero Error
+25°C (Tech note 1)
—
±0.1
±0.15
%FSR
0 to +70°C
—
±0.1
±0.25
%FSR
–55 to +125°C
—
±0.25
±0.5
%FSR
Bipolar Offset Error
+25°C (Tech note 1)
—
±0.05
±0.1
%FSR
0 to +70°C
—
±0.1
±0.25
%FSR
–55 to +125°C
—
±0.25
±0.45
%FSR
Gain Error
+25°C (Tech note 1)
—
±0.1
±0.3
%FSR
0 to +70°C
—
±0.15
±0.45
%FSR
–55 to +125°C
—
±0.25
±0.75
%FSR
No Missing Codes
14 Bits
0 to +70°C
13 Bits
–55 to +125°C
Resolution
14 Bits
Output Coding
Pin 8 High
Staight binary/Offset binary/ 2's Comp.
Pin 8 Low
Comp. binary/Comp. offset binary/C2C
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA
MIN.
TYP.
MAX.
Logic Level
Logic "1"
+2.4
Logic "0"
—
Logic Loading "1"
—
Logic Loading "0"
—
Internal Reference Voltage, +25°C +9.98
Drift
—
External Current
—
—
—
—
—
+10.0
±30
—
—
+0.4
–4
+4
+10.02
—
2
Volts
Volts
mA
mA
Volts
ppm/°C
mA
—
—
–90
–82
–83
–77
dB
dB
78
74
83
77
—
—
dB
dB
77
72
80
76
—
—
dB
dB
—
80
—
dB
6
1.75
—
—
—
—
—
—
—
90
±90
±20
50
—
—
—
—
—
—
—
500
MHz
MHz
dB
V/μs
ns
ps rms
ns
—
—
500
680
600
—
750
1000
—
ns
ns
kHz
+14.5
–14.5
+4.75
+15.0
–15.0
+5.0
+15.5
–15.5
+5.0
Volts
Volts
Volts
—
—
—
—
—
+78
–65
+68
2.5
—
+110
–95
+95
3.4
±0.02
mA
mA
mA
Watts
%FSR%V
DYNAMIC PERFORMANCE
Total Harm. Distort. (–0.5dB)
dc to 100kHz
100kHz to 250kHz
SNR (wo/distortion, –0.5dB)
dc to 100kHz
100kHz to 250kHz
SNR (& distortion, –0.5dB)
dc to 100kHz
100kHz to 250kHz
Two-tone Intermodulation Distortion
(fin = 100kHz, 240kHz,
fs = 500khz, –0.5dB)
Input Bandwith (–3dB)
Small Signal (–20dB input)
Large Signal (0.5dB input)
Feedthrough (25 kHz)
Slew Rate
Aperture Delay Time
Aperture Uncertainty
Overvoltage Recovery Time; 20%
S/H Acq. Time
(to 0.003%FS (10V step)
Overvoltage Recovery, ±12V
A/D Conversion Rate
POWER REQUIREMENTS
Power Supply Range
+15V Supply
–15V Supply
+5V Supply
Power Supply Current
+15V Supply
–15V Supply
+5V Supply ➀
Power Dissipation
Power Supply Rejection
PHYSICAL/ENVIRONMENTAL
Operating Temp. Range, Case
ADS-928MC
ADS-928MM
Storage Temperature Range
Package Type
Weight
UNITS
0
—
+70
°C
–55
—
+125
°C
–65
—
+150
°C
32-pin, hermetic sealed, ceramic TDIP
0.42 ounces (12 grams)
➀ All power supplies should be on before applying a start convert pulse. All supplies
and the clock (start convert pulse) must be present during warm up period.
Table 1. Input Connections
• Tel: (508) 339-3000
•
INPUT RANGE
INPUT PIN
TIE TOGETHER
0 to -10V
Pin 3
Pins 2 and 4
±5V
Pin 3
Pins 1 and 2
www.datel.com
•
e-mail: [email protected]
27 Jul 2015
MDA_ADS-928.B02 Page 2 of 4
ADS-928
500kHz, 14-Bit Sampling A/D Converters
TECHNICAL NOTES
CALIBRATION PROCEDURE
1. Use external potentiometers to remove system errors or the small initial
errors to zero. Use a 20k trimming potentiometer for gain adjustment with
the wiper tied to pin 6 (ground pin 6 for operation without adjustments).
Use a 20k trimming potentiometer with the wiper tied to pin 5 for zero/
offset adjustment (connect pin 5 to pin 15, analog ground for operation
without adjustment).
1. Connect the converter per Figure 3, and Table 1 for the appropriate fullscale range (FSR). Apply a pulse of 200 nanoseconds minimum to the
START CONVERT input (pin 32) at a rate of 200kHz. This rate is chosen to
reduce flicker if LED's are used on the outputs for calibration purposes.
2. Zero Adjustments Apply a precision voltage reference source between
the analog input (pin 3) and signal ground (pin 4). Adjust the output of the
reference source per Table 2.
2. Rated performance requires using good high-frequency circuit board
layout techniques. The analog and digital grounds are not connected
internally. Avoid ground-related problems by connecting the digital and
analog grounds to one point, the ground plane beneath the converter. Due
to the inductance and resistance of the power supply return paths, return
the analog and digital ground separately to the power supplies.
For unipolar, adjust the zero trimming potentiometer so that the output
code flickers equally between 00 0000 0000 0000 and 00 0000 0000
0001 with the COMP BIN (pin 8) tied high (straight binary) or between 11
1111 1111 1111 and 11 1111 1111 1110 with the pin 8 tied low (complementary binary).
3. Bypass the analog and digital supplies and the +1OV reference (pin 1) to
ground with a 4.7μF, 25V tantalum electrolytic capacitor in parallel with
a 0.1 μF ceramic capacitor. Bypass the +10V reference (pin 1) to analog
ground (pin 15).
For bipolar operation, adjust the potentiometer such that the code flickers
equally between 10 0000 0000 0000 and 10 0000 0000 0001 with pin
8 tied high (offset binary) or between 01 1111 1111 1111 and 01 1111
1111 1110 with pin 8 tied low (complementary offset binary).
4. Obtain straight binary/offset binary output coding by tying COMP BIN (pin
8) to +5V or leaving it open. The device has an internal pull-up resistor
on this pin. To obtain complementary binary or complementary offset binary
output coding, tie the COMP BIN pin to ground. The COMP BIN signal is compatible to CMOS/TTL logic levels for those users desiring logic control of this
function.
Two's complement coding requires use of the MSB (pin 31) with pin 8 tied
high, adjusting the potentiometer such that the code flickers between 00
0000 0000 0000 and 00 0000 0000 0001.
3. Full-Scale Adjustment
Set the output of the voltage reference used in step 2 to the value shown
in Table 2.
5. To enable the three-state outputs, connect ENABLE (pin 9) to a logic ·"0"·
(low). To disable, connect ENABLE (pin 9) to a logic "1" (high).
Adjust the gain trimming potentiometer so that the output code flickers
equally between 11 1111 1111 1110 and 11 1111 1111 1111 for pin 8
tied high (straight binary) or between 00 0000 0000 0000 and 00 0000
0000 0001 for pin 8 tied low (complementary binary).
6. The 200 ns minimum START CONVERT pulse width assures the hold mode
settling time requirements are met.
7. The specifications listed in Figure 2 (timing diagram) apply over the full
operating temperature range unless otherwise specified.
Two's complement coding requires use of the MSB (pin 31) with the pin 8
tied high, adjusting the gain trimming potentiometer so that the output code
flickers equally between 01 1111 1111 1110 and 01 1111 1111 1111.
Table 2. Zero and Gain Adjust
FSR
ZERO ADJUST +½ LSB
GAIN ADJUST FS - ½ LSB
0 to -10V
-305 μV
-9.999085V
±5V
+305V
+4.999085V
4. To confirm proper operation of the device, vary the precision reference
voltage source to obtain the output coding listed in Table 3.
HOLD MODE SETTLING
280ns min.
START
CONVERT
N
S/H ACQ. TIME
S/H
CONTROL
OUT
(INTERNAL)
A/D EOC
OUT
30ns min.
HOLD
SAMPLE
10ns min., 25ns max.
BUSY
25ns min.
EOC
20ns min., 35ns max.
700ns min.
OUTPUT
DATA
DATA N-1 VALID
DATA N VALID
INVALID
ENABLE
ENABLED DATA N VALID
10ns max. DATA INHIBITED
10ns max.
NOTES: NOT DRAWN TO SCALE
Retriggering START CONVERT before EOC
goes low will not start a new conversion.
Figure 2. ADS-928 Timing Diagram
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA
• Tel: (508) 339-3000
•
www.datel.com
•
e-mail: [email protected]
27 Jul 2015
MDA_ADS-928.B02 Page 3 of 4
ADS-928
500kHz, 14-Bit Sampling A/D Converters
UNIPOLAR
SCALE
FS -1 LSB
7/8 FS
3/4 FS
1/2 FS
1/4 FS
1/8 FS
1 LSB
0
STRAIGHT BIN. COMP. BINARY
OUTPUT CODING
COMP. BINARY
MSB
LSB
MSB
LSB
MSB
LSB
11 1111 1111 1111
00 0000 0000 0000
01 1111 1111 1111
11 1000 0000 0000
00 0111 1111 1111
01 1000 0000 0000
11 0000 0000 0000
00 1111 1111 1111
01 0000 0000 0000
10 0000 0000 0000
01 1111 1111 1111
00 0000 0000 0000
01 0000 0000 0000
10 1111 1111 1111
10 0000 0000 0000
00 1000 0000 0000
11 0111 1111 1111
10 1000 0000 0000
00 0000 0000 0001
11 1111 1111 1110
10 0000 0000 0001
00 0000 0000 0000
11 1111 1111 1111
10 0000 0000 0000
OFF. BINARY COMP. OFF. BIN.
INPUT RANGES, Vdc
0 to ·10V
-9.999390
-8.750000
-7.500000
-5.000000
-2.500000
-1.250000
-0.000610
0.000000
INPUT RANGE
±5Vdc
-4.99939
-3.75000
-2.50000
0.00000
+2.50000
+3.75000
+4.99939
+5.00000
BIPOLAR
SCALE
+FS -1 LSB
+3/4 FS
+1/2 FS
0
-1/2 FS
-3/4 FS
-FS +1 LSB
-FS
Table 3. Output Coding for Unipolar Operation
0.235 MAX.
(5.969)
-15V
4.7μF
4.7μF
4.7μF
+
+
+
0.1μF
0.1μF
0.1μF
15
13
12
6
20KΩ
-15V
0.1μF
09
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
07
16
GAIN ADJUST
4.7μF
3
8
32
14
4
ADS-928
BIPOLAR
0.100 BSC
(2.54)
11
+10V REF. OUT
2
+5V DC
10
PIN 1
INDEX
0.021/0.016
(0.534/0.406)
1
+
0 to -10V
0.035/0.015
(0.889/0.381)
GAIN
ADJUST
+15V
0.190 MAX.
(4.826)
+5V
ANALOG INPUT
COMP BIN
START CONVERT
NO CONNECTION
SIGNAL GROUND
ENABLE
BIT 1 (MSB)
BIT 1 (MSB)
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
BIT 8
BIT 9
BIT 10
BIT 11
BIT 12
BIT 13
BIT 14 (LSB)
OVERFLOW
EOC
0.045/0.035
(1.143/0.889)
0.11/0.09
(2.80/2.28)
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
0.200/0.175
(5.08/4.44)
SEATING
PLANE
1.11/1.08
(28.20/27.43)
5
0.015/0.009
(0.381/0.228)
20KΩ
-15V
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1.72/1.69
(43.69/42.92)
+15V
+15V
0.92/0.89
(23.37/22.60)
ZERO/OFFSET ADJUST
Figure 3. Typical ADS-928 Connection Diagram
MECHANICAL DIMENSIONS
INCHES (mm)
ORDERING INFORMATION
MODEL
NUMBER
OPERATING
TEMP. RANGE
SEAL
ADS-928MC
0 to +70°C
Hermetic
ADS-928MM -55 to +125°C
Hermetic
ACCESSORIES
ADS-EVAL1
Evaluation Board (without ADS-928)
Receptacle for PC board mounting can be ordered
through AMP Inc., Part # 3-331272-8 (Component Lead
Socket), 32 required.
For availibility of MIL-STD-883B versions, contact DATEL.
Figure 4. ADS-928 FFT Analysis
DATEL is a registered trademark of DATEL, Inc.
11 Cabot Boulevard, Mansfield, MA 02048-1151 USA
DATEL, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other technical information
contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply the granting of
licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without notice.
ITAR and ISO 9001/14001 REGISTERED
© 2015 DATEL, Inc.
www.datel.com • e-mail: [email protected]
27 Jul 2015
MDA_ADS-928.B02 Page 4 of 4