ADS-953

ADS-953
18-Bit, 1MHz, Low-Distortion Sampling A/D Converters
PRODUCT OVERVIEW
The ADS-953 is an 18-bit, 1MHz sampling
A/D converter. This device accurately samples
full-scale input signals up to Nyquist frequencies
with no missing codes. This feature, combined
with excellent signal-to-noise ratio (SNR) and
–95dB peak harmonic distortion (THD), makes the
ADS-953 the ideal choice for both time-domain
(medical imaging, scanners, process control) and
frequency-domain (radar, telecommunications,
spectrum analysis) applications.
Packaged in a 32-pin, side-brazed, metalsealed, ceramic TDIP, the functionally complete
ADS-953 contains a fast-settling sample-hold
amplifier, a subranging (two-pass) A/D converter,
an internal reference, timing/control logic, and
error-correction circuitry. Digital input and output
levels are TTL, and the ADS-953 only requires the
rising edge of the start convert pulse to operate.
Requiring ±15V and ±5V supplies, the ADS953 typically dissipates 1.45 Watts. The device is
offered with a bipolar (±5V) analog input range.
Models are available for use in either commer-
FEATURES
„ 18-bit resolution
„ 1MHz minimum sampling rate
„ No missing codes over extended temperature
range
„ Very low power, 1.45 Watts
„ Small, 32-pin, side-brazed, ceramic TDIP
„ Edge-triggered
„ Excellent performance, –95dB peak harmonics
„ Ideal for both time and frequency-domain
applications
„ Low cost
cial (0 to +70°C) or extended (–40 to +110°C)
operating temperature ranges. A proprietary,
auto-calibrating, error-correcting circuit enables
the device to achieve specified performance over
the full military temperature range.
PIN
INPUT/OUTPUT CONNECTIONS
FUNCTION
PIN FUNCTION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
BIT 2
BIT 1 (MSB)
ANALOG GROUND
ANALOG INPUT
+5V REFERENCE OUT
GAIN ADJUST
COMPENSATION
–15V SUPPLY
+15V SUPPLY
+5V ANALOG SUPPLY
–5V ANALOG SUPPLY
ANALOG GROUND
DIGITAL GROUND
+5V DIGITAL SUPPLY
EOC
START CONVERT
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
BIT 8
BIT 9
BIT 10
BIT 11
BIT 12
BIT 13
BIT 14
BIT 15
BIT 16
BIT 17
BIT 18 (LSB)
BLOCK DIAGRAM
BIT 1 (MSB)
1
BIT 2
32 BIT 3
BUFFER
ANALOG INPUT 4
2
–
31 BIT 4
FLASH
ADC
1
S/H
+
30 BIT 5
29 BIT 6
28 BIT 7
REF
DAC
Σ
+5V REFERENCE OUT 5
COMPENSATION 7
FLASH
ADC
2
AMP
27 BIT 8
DIGITAL CORRECTION LOGIC
GAIN ADJUST 6
GAIN
CIRCUIT
26 BIT 9
25 BIT 10
24 BIT 11
23 BIT 12
22 BIT 13
21 BIT 14
20 BIT 15
19 BIT 16
18 BIT 17
17 BIT 18 (LSB)
START CONVERT 16
TIMING AND
CONTROL LOGIC
EOC 15
10
+5V ANALOG
SUPPLY
11
–5V ANALOG
SUPPLY
3, 12
14
ANALOG
GROUND
+5V DIGITAL
SUPPLY
9
8
+15V
SUPPLY
13
–15V
SUPPLY
DIGITAL
GROUND
Figure 1. ADS-953 Functional Block Diagram
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA
• Tel: (508) 339-3000
•
www.datel.com
•
e-mail: help@datel.com
11 Sep 2015
MDA_ADS-953.B03 Page 1 of 6
ADS-953
18-Bit, 1MHz, Low-Distortion Sampling A/D Converters
ABSOLUTE MAXIMUM RATINGS
PARAMETERS
LIMITS
+15V Supply (Pin 9)
0 to +16
–15V Supply (Pin 8)
0 to –16
+5V Supply (Pins 10, 14)
0 to +6
–5V Supply (Pin 11)
0 to –6
Digital Input (Pin 16)
–0.3 to +VDD +0.3
Analog Input (Pin 4)
±15
Lead Temperature (10 seconds)
+300
UNITS
Volts
Volts
Volts
Volts
Volts
Volts
°C
PARAMETERS
Operating Temp. Range, Case
ADS-953MC
ADS-953ME
Thermal Impedance
θjc
θca
Storage Temperature Range
Package Type
Weight
PHYSICAL/ENVIRONMENTAL
MIN.
TYP.
0
–40
—
—
MAX.
UNITS
+70
+110
°C
°C
—
5
—
°C/Watt
—
22
—
°C/Watt
–65
—
+150
°C
32-pin,side-brazed, metal-sealed, ceramic TDIP
0.46 ounces (13 grams)
FUNCTIONAL SPECIFICATIONS
(TA = +25°C, ±VCC = ±15V, ±VDD = ±5V, 1MHz sampling rate, and a minimum 1 minute warmup ➀ unless otherwise specified.)
ANALOG INPUT
MIN.
—
Input Voltage Range d
Input Resistance
—
Input Capacitance
—
DIGITAL INPUT
Logic Levels
Logic "1"
+2.0
Logic "0"
—
Logic Loading "1"
—
Logic Loading "0"
—
Start Convert Positive Pulse Width ➂
20
STATIC PERFORMANCE
Resolution
—
Integral Nonlinearity (fin = 10kHz)
—
Differential Nonlinearity (fin = 10kHz)
–0.95
Full Scale Absolute Accuracy
—
Bipolar Zero Error (Tech Note 2)
—
Bipolar Offset Error (Tech Note 2)
—
Gain Error (Tech Note 2)
—
No Missing Codes (fin = 10kHz)
18
DYNAMIC PERFORMANCE (500kHz SAMPLING RATE)
Peak Harmonics (–0.5dB)
dc to 1kHz
—
dc to 100kHz
—
Total Harmonic Distortion (–0.5dB)
dc to 100kHz
—
Signal-to-Noise Ratio (w/o distortion, –0.5dB)
dc to 100kHz
91
Signal-to-Noise Ratio f (& distortion, –0.5dB)
dc to 100kHz
76
DC Noise
—
Two-Tone Intermodulation Distortion
(fin = 100kHz, 240kHz, fs = 500kHz, –0.5dB)
—
Input Bandwidth (–3dB)
Small Signal (–20dB input)
—
Large Signal (–0.5dB input)
—
Feedthrough Rejection (fin = 500kHz)
—
Slew Rate
—
Aperture Delay Time
—
Aperture Uncertainty
—
S/H Acquisition Time ( to ±0.003%FSR, 10V step)
—
Overvoltage Recovery Time ➄
—
A/D Conversion Rate
1
ANALOG OUTPUT
Internal Reference
Voltage
+4.95
Drift
—
External Current
—
+25°C
TYP.
±5
500
7
MAX.
—
—
15
MIN.
—
—
—
0 TO +70°C
TYP.
±5
500
7
MAX.
—
—
15
MIN.
—
—
—
–40 TO +110°C
TYP.
±5
500
7
MAX.
—
—
15
UNITS
Volts
Ω
pF
—
—
—
—
500
—
+0.8
+20
–20
—
+2.0
—
—
—
20
—
—
—
—
500
—
+0.8
+20
–20
—
+2.0
—
—
—
20
—
—
—
—
500
—
+0.8
+20
–20
—
Volts
Volts
μA
μA
ns
18
±10
±0.5
±0.1
±0.1
±0.1
±0.1
—
—
—
+1
±0.25
±0.15
±0.2
±0.25
—
—
—
–0.95
—
—
—
—
18
18
±10
±0.5
±0.25
±0.15
±0.2
±0.25
—
—
—
+1
±0.4
±0.25
±0.3
±0.4
—
—
—
–0.95
—
—
—
—
18
18
±15
±0.50
±0.4
±0.25
±0.3
±0.4
—
—
—
+1.25
±0.8
±0.5
±0.6
±0.9
—
Bits
LSB
LSB
%FSR
%FSR
%FSR
%
Bits
–95
–87
–93
—
—
—
–95
—
–93
—
—
—
–82
–80
—
—
dB
dB
–85
–80
—
–85
–80
—
–81
—
dB
93
—
91
93
—
—
92
—
dB
84
76
—
—
76
—
84
76
—
—
—
—
80
76
—
—
dB
μVrms
–85
—
—
–85
—
—
–81
—
d
1.2
1.1
84
TBD
+20
5
260
500
—
—
—
—
—
—
—
—
1000
—
—
—
—
—
—
—
—
—
1
1.2
1.1
84
TBD
+20
5
260
500
—
—
—
—
—
—
—
—
1000
—
—
—
—
—
—
—
—
—
1
1.2
1.1
84
TBD
+20
5
260
500
—
—
—
—
—
—
—
—
1000
—
MHz
MHz
dB
V/μs
ns
ps rms
ns
ns
MHz
+5.0
±30
1
+5.05
—
—
+4.95
—
—
+5.0
±30
1
+5.05
—
—
+4.95
—
—
+5.0
±30
1
+5.05
—
—
Volts
ppm/°C
mA
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA
• Tel: (508) 339-3000
•
www.datel.com
•
e-mail: help@datel.com
11 Sep 2015
MDA_ADS-953.B03 Page 2 of 6
ADS-953
18-Bit, 1MHz, Low-Distortion Sampling A/D Converters
DIGITAL OUTPUTS
Logic Levels
Logic "1"
Logic "0"
Logic Loading "1"
Logic Loading "0"
Output Coding
POWER REQUIREMENTS
Power Supply Ranges
+15V Supply
–15V Supply
+5V Supply
–5V Supply
Power Supply Currents
+15V Supply
–15V Supply
+5V Supply
–5V Supply
Power Dissipation
Power Supply Rejection
MIN.
+25°C
TYP.
MAX.
MIN.
+2.4
—
—
—
—
—
—
—
—
+0.4
–4
+4
+2.4
—
—
—
+14.5
–14.5
+4.75
–4.75
+15.0
–15.0
+5.0
–5.0
+15.5
–15.5
+5.25
–5.25
+14.5
–14.5
+4.75
–4.75
+15.0
–15.0
+5.0
–5.0
—
—
—
—
—
—
+29
–15
+104
–54
1.45
—
40
–25
125
–70
1.65
±0.05
—
—
—
—
—
—
+29
–15
+104
–54
1.45
—
Footnotes:
➀ All power supplies should 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.
➁ Contact DATEL for other input voltage ranges.
➂ A 1MHz clock with a 500nsec positive pulse width (50% duty cycle) is used for
all production testing. Any duty cycle may be used as long as a minimum positive
pulse width of 20nsec is maintained. For applications requiring lower sampling
rates, clock frequencies lower than 1MHz may be used.
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA
0 TO +70°C
TYP.
MIN.
–40 TO +110°C
TYP.
MAX.
UNITS
+2.4
—
—
—
—
—
—
—
—
+0.4
–4
+4
Volts
Volts
mA
mA
+15.5
–15.5
+5.25
–5.25
+14.5
–14.5
+4.75
–4.75
+15.0
–15.0
+5.0
–5.0
+15.5
–15.5
+5.25
–5.25
Volts
Volts
Volts
Volts
40
–25
125
–70
1.65
±0.05
—
—
—
—
—
—
+29
–15
+104
–54
1.45
—
40
–25
125
–70
1.65
±0.05
mA
mA
mA
mA
Watts
%FSR/%V
MAX.
—
—
—
+0.4
—
–4
—
+4
Complementary Offset Binary
➃ Effective bits is equal to:
(SNR + Distortion) – 1.76 +
20 log
Full Scale Amplitude
Actual Input Amplitude
6.02
➄ This is the time required before the A/D output data is valid once the analog input
is back within the specified range.
• Tel: (508) 339-3000
•
www.datel.com
•
e-mail: help@datel.com
11 Sep 2015
MDA_ADS-953.B03 Page 3 of 6
ADS-953
18-Bit, 1MHz, Low-Distortion Sampling A/D Converters
TECHNICAL NOTES
THERMAL REQUIREMENTS
1. Obtaining fully specified performance from the ADS-953 requires careful
attention to pc-card layout and power supply decoupling. The device's analog and digital ground systems are not connected to each other internally.
For optimal performance, tie all ground pins (3, 12 and 13) directly to a
large analog ground plane beneath the package.
Bypass all power supplies and the +5V REFERENCE OUTPUT (pin 5) to
ground with 10μF tantalum capacitors in parallel with 0.1μF ceramic capacitors. Locate the bypass capacitors as close to the unit as possible. Tie a
47μF capacitor between COMPENSATION (pin 7) and ground.
2. The ADS-953 achieves its specified accuracies without the need for external calibration. If required, the device's small initial errors can be reduced
to zero using the adjustment circuitry shown in Figure 2. When using this
circuitry, or any similar offset and gain calibration hardware, make adjustments following warmup. To avoid interaction, always adjust offset before
gain. Float pin 6 if not using gain adjust circuits.
All DATEL sampling A/D converters are fully characterized and specified over operating temperature (case) ranges of 0 to +70°C and –40
to +110°C. All room-temperature (TA = +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. Electricallyinsulating, 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.
3. Applying a start convert pulse while a conversion is in progress (EOC =
logic "1") will initiate a new and probably inaccurate conversion cycle. Data
for the interrupted and subsequent conversions will be invalid.
CALIBRATION PROCEDURE
Gain Adjust Procedure
Connect the converter per Table 1 for the appropriate input voltage range.
Any offset/gain calibration procedures should not be implemented until the
device is fully warmed up. To avoid interaction, adjust offset before gain.
The ranges of adjustment for the circuits in Figure 2 are guaranteed to
compensate for the ADS-953's initial accuracy errors and may not be able
to compensate for additional system errors.
1. Apply –4.999943V to the ANALOG INPUT (pin 4).
2. Adjust the gain potentiometer until all output bits are 1's and the LSB flickers between 1 and 0.
3. To confirm proper operation of the device, vary the applied input voltage to
obtain the output coding listed in Table 2.
A/D converters are calibrated by positioning their digital outputs exactly
on the transition point between two adjacent digital output codes. This is
accomplished by connecting LED's to the digital outputs and performing
adjustments 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.
For the ADS-953, offset adjusting is normally accomplished when the
analog input is 0 minus ½LSB (–19μV). See Table 2 for the proper bipolar
output coding.
Gain adjusting is accomplished when the analog input is at nominal full
scale minus 1½LSB's (–4.999943V).
Zero/Offset Adjust Procedure
1. Apply a train of pulses to the START CONVERT input (pin 16) so that the
converter is continuously converting.
2. For bipolar zero/offset adjust, apply –19μV to the ANALOG INPUT (pin 4).
3. Adjust the offset potentiometer until the output code flickers equally between 01 1111 1111 1111 1111 and 10 0000 0000 0000 0000.
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA
INPUT VOLTAGE
RANGE
ZERO ADJUST
(–½ LSB)
GAIN ADJUST
(–FS +1½ LSB)
±5V
–19μV
–4.999943
Table 1. Input Connections
BIPOLAR
SCALE
+FS –1 LSB
+3/4 FS
+1/2 FS
0
–1/2 FS
–3/4 FS
–FS +1 LSB
–FS
COMPLEMENTARY OFFSET BINARY
OUTPUT CODING
INPUT RANGE
±5V
MSB
LSB
+4.999962
00 0000 0000 0000 0000
+3.750000
00 0111 1111 1111 1111
+2.500000
00 1111 1111 1111 1111
+0.000000
01 1111 1111 1111 1111
–2.500000
10 1111 1111 1111 1111
–3.750000
11 0111 1111 1111 1111
–4.999962
11 1111 1111 1111 1110
–5.000000
11 1111 1111 1111 1111
Table 2. Output Coding
• Tel: (508) 339-3000
•
www.datel.com
•
e-mail: help@datel.com
11 Sep 2015
MDA_ADS-953.B03 Page 4 of 6
ADS-953
18-Bit, 1MHz, Low-Distortion Sampling A/D Converters
Pin 5 (ADS-953)
10k Ω
6
GAIN
ADJUST
15
EOC
2 BIT 1 (MSB)
1 BIT 2
32 BIT 3
14
+5V DIGITAL
31 BIT 4
30 BIT 5
0.1μF
10μF
13 DIGITAL
GROUND
+
10μF
0.1μF
+
10μF
27 BIT 8
26 BIT 9
0.1μF
25 BIT 10
12 ANALOG
GROUND
24 BIT 11
23 BIT 12
ADS-953
9
22 BIT 13
21 BIT 14
20 BIT 15
10
+5V ANALOG
19 BIT 16
+
10μF
18 BIT 17
0.1μF
3 ANALOG
GROUND
+
–5V ANALOG
28 BIT 7
8
–15V
+15V
29 BIT 6
10μF
0.1μF
17 BIT 18 (LSB)
16
START CONVERT
11
5 +5V
REF. OUT
0.1μF
47μF
7
COMPENSATION
+
4
ANALOG INPUT
10μF
Figure 2. Typical ADS-953 Connection Diagram
N
START
CONVERT
N+1
500ns typ.
5ns typ.
INTERNAL S/H
Acquisition Time
740ns typ.
260ns typ.
Hold
65ns typ.
EOC
Conversion Time
730ns typ.
20ns typ.
OUTPUT
DATA
Invalid Data
20ns
N
Data N-1 Valid
Data N-2 Valid
980ns typ.
Scale is approximately 50ns per division.
Figure 3. ADS-953 Timing Diagram
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA
• Tel: (508) 339-3000
•
www.datel.com
•
e-mail: help@datel.com
11 Sep 2015
MDA_ADS-953.B03 Page 5 of 6
ADS-953
18-Bit, 1MHz, Low-Distortion Sampling A/D Converters
MECHANICAL DIMENSIONS INCHES (mm)
1.62 MAX.
(41.15)
Dimension Tolerances
(unless otherwise indicated):
2 place decimal (.XX) ±0.010 (±0.254)
3 place decimal (.XXX) ±0.005 (±0.127)
0.92 MAX.
(23.37)
Lead Material: Kovar Alloy
Lead Finish: 50 microinches (minimum)
gold plating over 100 microinches
(nominal) nickel plating
1.50 TYP
(38.10)
SEATING PLANE
0.05 TYP.
(1.27)
0.220 TYP.
(6.86)
PIN 1 INDEX
0.010 TYP.
(0.254)
0.05 TYP.
(1.27)
0.018 TYP.
(0.46)
0.100 TYP.
(2.54)
0.90 TYP.
(22.86)
0.175 TYP
(4.45)
0.05 TYP.
(1.27)
ORDERING INFORMATION
MODEL
NUMBER
OPERATING
TEMP. RANGE
32-PIN
PACKAGE
ADS-953MC
0 to +70°C
TDIP
ADS-953ME
–40 to +110°C
TDIP
ACCESSORIES
ADS-B951*
Evaluation Board (without ADS-951)
Receptacles for PC mounting can be ordered through AMP Inc., Part # 3-331272-8 (Component Lead Socket), 32 required.
For availability of MIL-STD-883 product, contact DATEL.
* NOTE: The ADS-951 evalution board is used for the AD-953, as the ADS-951 and ADS-953, share a common pinout
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: help@datel.com
11 Sep 2015
MDA_ADS-953.B03 Page 6 of 6