Murata ADS-942 14-bit, 2mhz sampling a/d converter Datasheet

®
®
ADS-942
14-Bit, 2MHz
Sampling A/D Converters
FEATURES
•
•
•
•
•
•
•
•
•
14-bit resolution
2MHz minimum throughput
Functionally complete
Internal reference and sample/hold
-85dB total harmonic distortion
78dB signal-to-noise ratio
Full Nyquist-rate sampling
Small 32-pin DIP
Low-power, 2.9 Watts
INPUT/OUTPUT CONNECTIONS
GENERAL DESCRIPTION
DATEL's ADS-942 is a functionally complete, 14-bit, 2MHz,
sampling A/D converter. Its standard, 32-pin, triple-wide
ceramic DIP contains a fast-settling sample/hold amplifier, a
14-bit subranging (two-pass) A/D converter, a precision
reference, three-state output register and all the timing and
control logic necessary to operate from a single start
convert pulse.
The ADS-942 is optimized for wideband frequency-domain
applications and is fully FFT tested. The ADS-942 requires
±15V and +5V supplies and typically consumes 2.9 Watts.
PIN
FUNCTION
PIN
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
ANALOG GROUND
OVERFLOW
CODING SELECT
ENABLE
+5V SUPPLY
DIGITAL GROUND
+15V SUPPLY
–15V SUPPLY
ANALOG GROUND
ANALOG GROUND
EOC
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
FUNCTION
START CONVERT
BIT 1 OUT (MSB)
BIT 1 OUT (MSB)
BIT 2 OUT
BIT 3 OUT
BIT 4 OUT
BIT 5 OUT
BIT 6 OUT
BIT 7 OUT
BIT 8 OUT
BIT 9 OUT
BIT 10 OUT
BIT 11 OUT
BIT 12 OUT
BIT 13 OUT
BIT 14 OUT (LSB)
DAC
31 BIT 1 OUT (MSB)
30 BIT 1 OUT (MSB)
29 BIT 2 OUT
REGISTER
OFFSET ADJUST 5
S2
FLASH
ADC
BIPOLAR 2
BUFFER
S/H
REGISTER
ANALOG INPUT 3
S1
3-STATE OUTPUT REGISTER
OFFSET
CIRCUIT
DIGITAL CORRECTION LOGIC
REF
+10V REF. OUT 1
28 BIT 3 OUT
27 BIT 4 OUT
26 BIT 5 OUT
25 BIT 6 OUT
24 BIT 7 OUT
23 BIT 8 OUT
22 BIT 9 OUT
21 BIT 10 OUT
20 BIT 11 OUT
19 BIT 12 OUT
18 BIT 13 OUT
17 BIT 14 OUT (LSB)
START CONVERT 32
TIMING AND
CONTROL LOGIC
9 ENABLE
EOC 16
7 OVERFLOW
4
10
11
12
6, 14, 15
13
8
SIGNAL
GROUND
+5V
SUPPLY
DIGITAL
GROUND
+15V
SUPPLY
ANALOG
GROUND
–15V
SUPPLY
CODING
SELECT
Figure 1. ADS-942 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-942
ABSOLUTE MAXIMUM RATINGS
PARAMETERS
+15V Supply (Pin 12)
–15V Supply (Pin 13)
+5V Supply (Pin 10)
Digital Inputs (Pin 8,9, 32)
Analog Input (Pin 3)
Lead Temp. (10 seconds)
OUTPUTS
LIMITS
UNITS
0 to +16
0 to –16
0 to +6
–0.3 to +VDD +0.3
±15
+300
Volts
Volts
Volts
Volts
Volts
°C
Output Coding
Logic Level
Logic "1"
Logic "0"
Logic Loading "1"
Logic Loading "0"
Internal Reference
Voltage, +25°C
Drift
External Current
FUNCTIONAL SPECIFICATIONS
MIN.
TYP.
MAX.
UNITS
Input Voltage Range
Unipolar
Bipolar
Input Impedence
Input Capacitance
—
—
4.9
—
0 to +10
±5
5
7
—
—
—
15
Volts
Volts
kΩ
pF
+2.0
—
—
—
—
—
—
—
—
+0.8
+5
–600
Volts
Volts
µA
µA
—
—
—
±1
±1
±2
±2
±2
±3
LSB
LSB
LSB
–0.75
–0.95
–1
±0.5
±0.75
±1
±0.75
±1.25
+2.5
LSB
LSB
LSB
—
—
—
±0.1
±0.12
±0.45
±0.122
±0.36
±0.85
%FSR
%FSR
%FSR
—
—
—
±0.05
±0.1
±0.2
±0.122
±0.2
±0.3
%FSR
%FSR
%FSR
—
—
—
±0.05
±0.1
±0.2
±0.122
±0.2
±0.3
%FSR
%FSR
%FSR
—
—
—
±0.1
±0.12
±0.5
±0.2
±0.3
±0.8
%FSR
%FSR
%FSR
—
—
—
±0.018
±0.12
±0.6
±0.122
±0.3
±0.8
%
%
%
Total Harm. Distort. (–0.5dB)
dc to 100kHz
100kHz to 500kHz
500kHz to 1MHz
Signal-to-Noise Ratio
(w/o distortion, –0.5dB
dc to 100kHz
100kHz to 500kHz
500kHz to 1MHz
Signal-to-Noise Ratio
(and distortion, –0.5dB)
dc to 100kHz
100kHz to 500kHz
500kHz to 1MHz
Spurious Free Dyn. Range ➀
dc to 100kHz
100 to 500kHz
500kHz to 1MHz
Two-tone IMD
Distortion (fin = 100kHz,
240kHz, fs = 2.0Mhz,
–0.5dB)
Input Bandwidth (–3dB)
Small Signal (–20dB input)
Large Signal (–0.5dB input)
Slew Rate
Aperture Delay Time
Aperature Uncertainty
S/H Acq. Time, (to ±0.003%FSR)
Sinusoidal (fin = 1MHz)
Step input
Conversion Rate
Sinusoidal (fin = 1MHz)
Step input
Feedthrough Rejection
(fin = 1MHz)
Overvoltage Recovery, ±12V
Noise
DIGITAL INPUTS
Logic Levels
Logic "1"
Logic "0"
Logic Loading "1"
Logic Loading "0"
PERFORMANCE
Integral Non-Linearity
(fin = 1MHz)
+25°C
0 to +70°C
–40 to +85°C
Differential Non-Linearity
(fin = 1MHz)
+25°C
0 to +70°C
–40 to +85°C
Full Scale Absolute Accuracy
+25°C
0 to +70°C
–40 to +85°C
Unipolar Zero Error
+25°C (see Figure 3)
0 to +70°C
–40 to +85°C
Bipolar Zero Error
+25°C (see Figure 3)
0 to +70°C
–40 to +85°C
Bipolar Offset Error
+25°C (see Figure 3)
0 to +70°C
–40 to +85°C
Gain Error
+25°C (see Figure 3)
0 to +70°C
–40 to +85°C
No Missing Codes (fin = 500kHz)
14 Bits
13 Bits
Resolution
TYP.
MAX.
UNITS
Staight Bin./Offset Bin./2's Comp.
Comp. Bin./Comp. Offset Bin./C2C
+2.4
—
—
—
—
—
—
—
—
+0.4
–160
+6.4
Volts
Volts
µA
mA
+9.98
—
—
+10.0
±13
—
+10.02
±30
5
Volts
ppm/°C
mA
—
—
—
–85
–80
–77
–76
–75
—
dB
dB
dB
74
73
—
78
75
73
—
—
—
dB
dB
dB
73
72
—
78
75
72
—
—
—
dB
dB
dB
—
—
—
–86
–81
–78
–77
–75
—
dB
dB
dB
–85
—
—
dB
—
—
—
—
—
6
1.75
±250
—
—
—
—
—
±10
5
MHz
MHz
V/µs
ns
ps, ms
—
—
120
250
150
450
ns
ns
2
1.3
—
—
—
—
MHz
MHz
—
—
—
85
1000
250
—
2000
—
dB
ns
µVrms
+14.25
–14.25
+4.75
+15.0
–15.0
+5.0
+15.75
–15.75
+5.25
Volts
Volts
Volts
—
—
—
—
—
+65
–80
+150
2.9
—
+87
–98
+165
3.4
±0.02
mA
mA
mA
Watts
%FSR%V
DYNAMIC PERFORMANCE
(TA = +25°C, ±VCC = ±15V, +VDD = +5V, 2MHz sampling rate, and a minimum 7 minute
warmup unless otherwise specified.)
ANALOG INPUTS
MIN.
POWER REQUIREMENTS
Power Supply Ranges
+15V Supply
–15V Supply
+5V Supply
Power Supply Currents
+15V Supply
–15V Supply
+5V Supply
Power Dissipation
Power Supply Rejection
0 to +70°C
–40 to +85°C
14 Bits
PHYSICAL/ENVIRONMENTAL
Operating Temp. Range, Case
ADS-942MC
ADS-942ME
Storage Temperature Range
Package Type
Footnote:
➀ Same specification as In-Band Harmonics and Peak Harmonics.
Weight
2
0
—
+70
°C
–40
—
+85
°C
–65
—
+150
°C
32-pin, metal-sealed, ceramic TDIP
0.46 ounces (13 grams)
®
®
ADS-942
TECHNICAL NOTES
For unipolar, adjust the zero trimpot so that the output code
flickers equally between 00 0000 0000 0000 and 00 0000
0000 0001 with CODING SELECT (pin 8) tied low (straight
binary) or between 11 1111 1111 1111 and 11 1111 1111
1110 with pin 8 tied high (complementary binary).
1. Rated performance requires using good high-frequency
circuit board layout techniques. Connect the digital and
analog grounds to one point, the analog 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.
SIGNAL GROUND (pin 4) is not internally connected to
ANALOG GROUND (pins 6, 15).
For bipolar operation, adjust the trimpot until the code
flickers equally between 10 0000 0000 0000 and 10 0000
0000 0001 with pin 8 tied low (offset binary) or between 01
1111 1111 1111 and 01 1111 1111 1110 with pin 8 tied high
(complementary offset binary).
2. Bypass the analog and digital supplies and the +10V REF.
OUT (pin 1) to ground with a 4.7µF, 25V tantalum electrolytic capacitor in parallel with a 0.1µF ceramic capacitor.
Two's complement coding requires using BIT 1 OUT (MSB)
(pin 31). With pin 8 tied low, adjust the trimpot until the code
flickers between 00 0000 0000 0000 and 00 0000 0000
0001.
3. CODING SELECT(pin 8) is compatible with CMOS/TTL
logic levels for those users desiring logic control of this
function. There is an internal pull-up resistor on this pin;
connect to +5V or leave open for logic 1. See the Calibration Procedure for selecting an output coding.
3. Full-Scale Adjustment
Set the output of the voltage reference used in step 2 to the
value shown in Table 2.
4. To enable the three-state outputs, connect ENABLE (pin 9)
to a logic "0" (low). To disable, connect pin 9 to a logic "1"
(high).
Table 2. Zero and Gain Adjustments
Table 1. Input Connections
INPUT RANGE
INPUT PIN
TIE TOGETHER
0 +10V
±5V
Pin 3
Pin 3
Pins 2 and 4
Pins 1 and 2
CALIBRATION PROCEDURE
0 to +10V
±5V
+305µV
+305µV
Apply a precision voltage reference source between
ANALOG INPUT (pin 3) and SIGNAL GROUND (pin 4),
then adjust the reference source output per Table 2.
N+1
35ns max..
Conversion Time
300ns typ., 325ns max.
10ns typ.
15ns max.
INTERNAL S/H
35ns typ.
Hold
150ns max.
Aquisition Time
350ns min.
30ns max.
OUTPUT
DATA
+9.999085V
+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.
35ns min., 50ns typ., 60 ns max
EOC
Gain Adjust
FS – 1½ LSB
Two’s complement coding requires using pin 31. With pin 8
tied low, adjust the gain trimpot until the output code flickers
equally between 01 1111 1111 1110 and 01 1111 1111
1111.
2. Zero Adjustments
N
Zero Adjust
+1/2 LSB
Adjust the gain trimpot until the output code flickers equally
between 11 1111 1111 1110 and 11 1111 1111 1111 with
pin 8 tied low for straight binary/offset binary or between 00
0000 0000 0000 and 00 0000 0000 0001 with pin 8 tied high
for complementary binary/complementary offset binary.
1. Connect the converter per Figure 3 and Table 1 for the
appropriate input voltage range. Apply a pulse of 35
nanoseconds minimum to START CONVERT (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.
START
CONVERT
Input
Range
DATA N VALID
DATA N-1 VALID
INVALID DATA
200ns max.
300ns min.
Note: Scale is approximately 25ns per division.
Figure 2. ADS-942 Timing Diagram
3
®
®
ADS-942
ZERO/OFFSET
ADJUST
20kΩ
+15V
+5V
0.1µF
4.7µF
4.7µF
+
0.1µF
4.7µF
–15V
5
OFFSET
ADJUST
10
29 BIT 2 OUT
28 BIT 3 OUT
0.1µF
27 BIT 4 OUT
26 BIT 5 OUT
12
25 BIT 6 OUT
24 BIT 7 OUT
6, 14, 15 ANALOG
GROUND
23 BIT 8 OUT
22 BIT 9 OUT
21 BIT 10 OUT
13
20 BIT 11 OUT
19 BIT 12 OUT
ADS-942
GAIN ADJUST
0 to +10V
31 BIT 1 OUT (MSB)
30 BIT 1 OUT (MSB)
DIGITAL
11 GROUND
+
+15V
–15V
18 BIT 13 OUT
17 BIT 14 OUT (LSB)
7 OVERFLOW
16 EOC
3 ANALOG INPUT
100Ω
4 SIGNAL GROUND
CODING SELECT
+5V
8
START CONVERT 32
1 +10V REF. OUT
0.1µF
4.7µF
ENABLE
9
BIPOLAR
2
Figure 3. ADS-942 Connection Diagram
Removing System Errors
adjustment. Use a 20kΩ trimpot with the wiper tied to OFFSET
ADJUST (pin 5) for zero/offset adjustment. Connect pin 5 to
ANALOG GROUND (pin 6) for operation without zero/offset
adjustment.
Use external potentiometers to remove system errors or to
reduce the small initial errors to zero. Use a 100Ω trimpot in
series with the analog input for gain adjustment. Use a fixed
50Ω resistor instead of the trimpot for operation without
Table 3. Output Coding
STRAIGHT BIN.
COMP. BINARY
UNIPOLAR
SCALE
INPUT VOLT.
0 TO +10V
MSB
LSB
OUTPUT CODING
MSB
LSB
MSB
LSB
INPUT VOLT.
±5V
BIPOLAR
SCALE
+FS – 1 LSB
+7/8 FS
+3/4 FS
+1/2 FS
+1/4 FS
+1/8 FS
+1 LSB
0
+9.999390
+8.750000
+7.500000
+5.000000
+2.500000
+1.250000
+0.000610
0.000000
11 1111 1111 1111
11 1000 0000 0000
11 0000 0000 0000
10 0000 0000 0000
01 0000 0000 0000
00 1000 0000 0000
00 0000 0000 0001
00 0000 0000 0000
00 0000 0000 0000
00 0111 1111 1111
00 1111 1111 1111
01 1111 1111 1111
10 1111 1111 1111
11 0111 1111 1111
11 1111 1111 1110
11 1111 1111 1111
01 1111 1111 1111
01 1000 0000 0000
01 0000 0000 0000
00 0000 0000 0000
11 0000 0000 0000
10 1000 0000 0000
10 0000 0000 0001
10 0000 0000 0000
+4.999390
+3.750000
+2.500000
0.000000
–2.500000
–3.750000
–4.999390
–5.000000
+FS – 1LSB
+3/4FS
+1/2FS
0
–1/2FS
–3/4FS
–FS+1LSB
–FS
COMP. OFF. BIN.
TWO'S COMP.
OFF. BINARY
4
®
®
ADS-942
THERMAL REQUIREMENTS
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.
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 (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.
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.
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
0
–10
Amplitude Relative to Full Scale (dB)
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
–120
–130
–140
–150
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Frequency (MHz)
(fs = 2MHz, fin = 490kHz, Vin = –0.5dB, 16,384-point FFT)
Figure 4. FFT Analysis of ADS-942
5
0.9
1
®
®
ADS-942
MECHANICAL DIMENSIONS INCHES (mm)
1.72 MAX.
(43.69)
32
Dimension Tolerances (unless otherwise indicated):
2 place decimal (.XX) ±0.010 (±0.254)
3 place decimal (.XXX) ±0.005 (±0.127)
17
Lead Material: Kovar alloy
Lead Finish: 50 microinches (minimum) gold plating
over 100 microinches (nominal) nickel plating
1.11 MAX.
(28.19)
1
16
0.100 TYP.
(2.540)
0.235 MAX.
(5.969)
1.500
(38.100)
0.200 MAX.
(5.080)
+0.002
0.010 –0.001
(0.254)
0.190 MAX.
(4.826)
0.018 ±0.002
(0.457)
SEATING
PLANE
0.025
(0.635)
0.100
(2.540)
0.040
(1.016)
0.900 ±0.010
(22.860)
0.100
(2.540)
ORDERING INFORMATION
MODEL NUMBER
OPERATING TEMP. RANGE
ADS-942MC
0 to +70°C
ADS-942ME
–40 to +85°C
ACCESSORIES
ADS-EVAL4
HS-32
Evaluation Board (without ADS-942)
Heat Sink for all ADS-942 models
Receptacles for PC mounting can be ordered through AMP Inc., Part # 3-331272-8 (Component Lead Socket), 32 required.
®
®
ISO 9001
R
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151
Tel: (508) 339-3000 (800) 233-2765
Fax: (508) 339-6356
Internet: www.datel.com E-mail:[email protected]
Data Sheet Fax Back: (508) 261-2857
E
G
I
S
T
E
R
E
D
DS-0228B
10/96
DATEL (UK) LTD. Tadley, England Tel: (01256)-880444
DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 1-34-60-01-01
DATEL GmbH München, Germany Tel: 89-544334-0
DATEL KK Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-354-2025
DATEL 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. The DATEL logo is a registered DATEL, Inc. trademark.
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