www.murata-ps.com
ADS-112
12-Bit, 1MHz, Low-Power Sampling A/D Converters
PRODUCT OVERVIEW
DATEL’s ADS-112 is a 12-bit, functionally com-
plete, sampling A/D converter that is packaged in
a space-saving 24-pin DDIP. Requiring ±15V and
+5V supplies, a minimum sampling rate of 1MHz
is achieved while only dissipating 1.3 Watts. The
ADS-112 digitizes signals up to Nyquist frequen-
cies. Models are available for use in either com-
mercial (0 to + 70°C) or military (–55 to +125°C)
operating temperature ranges.
Typical applications include spectrum, tran-
sient, vibration and waveform analysis. This device
is also ideally suited for radar, sonar, video digitiza-
tion, medical instrumentation and highspeed data
acquisition systems.
INPUT/OUTPUT CONNECTIONS
PIN
1
2
3
4
5
6
7
8
9
10
11
12
FUNCTION
BIT 12 (LSB)
BIT 11
BIT 10
BIT 9
BIT 8
BIT 7
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
–15V SUPPLY
ANALOG GROUND
+15V SUPPLY
+10V REFERENCE
BIPOLAR
ANALOG INPUT
COMP BIN
ENABLE (1-12)
START CONVERT
EOC
DIGITAL GROUND
+5V SUPPLY
FEATURES
■
■
■
■
■
■
■
■
12-bit resolution
No missing codes
1MHz minimum sampling rate
Functionally complete
Small 24-pin DDIP
Low-power, 1.3 Watts
Three-state output buffers
Samples to Nyquist frequencies
17 ENABLE (1-12)
DAC
12 BIT 1 (MSB)
+10V REF. 21
S
2
S/H
S
1
BIPOLAR 20
REGISTER
BUFFER
FLASH
ADC
REF
DIGITAL CORRECTION LOGIC
3-STATE OUTPUT REGISTER
11 BIT 2
10 BIT 3
9
8
7
6
5
4
3
2
1
BIT 4
BIT 5
BIT 6
BIT 7
BIT 8
BIT 9
BIT 10
BIT 11
BIT 12 (LSB)
ANALOG INPUT 19
–
+
COMP BIN 18
START CONVERT 16
EOC 15
TIMING AND
CONTROL LOGIC
13
+5V SUPPLY
14
DIGITAL GROUND
22
+15V SUPPLY
REGISTER
23
ANALOG GROUND
24
–15V SUPPLY
Figure 1. ADS-112 Functional Block Diagram
For full details go to
www.murata-ps.com/rohs
www.murata-ps.com
Technical enquiries
email: data.acquisition@murata-ps.com, tel:
+1 508 339 3000
MDA_ADS-112.B01
Page 1 of 6
ADS-112
12-Bit, 1MHz, Low-Power Sampling A/D Converters
ABSOLUTE MAXIMUM RATINGS
PARAMETERS
+15V Supply (Pin 22)
–15V Supply (Pin 24)
+5V Supply (Pin 13)
Digital Inputs (Pin 16, 17, 18)
Analog Input (Pin 19)
Lead Temp. (10 seconds)
LIMITS
0 to +18
0 to –18
0 to +6
–0.3 to +VDD +0.3
–9 to +15
+300
UNITS
Volts
Volts
Volts
Volts
Volts
°C
DYNAMIC PERFORMANCE, CONT.
Signal-to-Noise Ratio
(wo/distort., –0.5dB)
dc to 100kHz
100kHz to 500kHz
Signal-to-Noise Ratio
➁
(& distort., –0.5dB)
dc to 100kHz
100kHz to 500kHz
Two-tone Intermodulation
Distortion
(fin = 75kHz,
105kHz, fs = 1MHz, –0.7dB)
Two-tone Intermodulation
Distortion
(fin = 480kHz,
490kHz, fs = 1MHz, –0.7dB)
Input Bandwith
(–3dB)
Small Signal (–20dB input)
Large Signal (–0.5dB input)
Slew Rate
Apperture Delay TIme
Effect. Aperture Delay Time
Apperture Uncertainity (Jitter)
RMS
Peak
Overvoltage Recovery Time
S/H Acquisition Time
Conversion Rate
(Changing Inputs)
+25°C
0°C to +70°C
–55°C to +125°C
Data Coding
Pin 18 High
Pin 18 Low
Logic Level
Logic "1"
Logic "0"
Logic Loading "1"
Logic Loading "0"
Power Supply Ranges
③
+15V Supply
–15V Supply
+5V Supply
Power Supply Current
+15V Supply
–15V Supply
+5V Supply
Power Dissipation
Power Supply Rejection
Operating Temp. Range, Case
ADS-112MC
ADS-112MM, 883
Storage Temperature Range
Package Type
Weight
➀
See Table 3 also
➁
Effective bits is equal to:
MIN.
TYP.
MAX.
UNITS
68
67
72
71
—
—
dB
dB
66
66
70
70
—
—
dB
dB
Functional Specifications
(T
A
= +25°C, ±V
CC
= ±15V, +V
DD
=+5V, 1MHz sampling rate, and a minimum 1 minute
warmup unless otherwise specified.)
—
–88
–80
dB
ANALOG INPUTS
Input Voltage Range
➀
Bipolar
Unipolar
Input Impedence
Input Capacitance
Logic Levels
Logic "1"
Logic "0"
Logic Loading "1"
Logic Loading "0"
Resolution
No Missing Codes
(12 Bits; fin = 1MHz)
Integral Non-Linearity
+25°C
0°C to +70°C
–55°C to +125°C
Differential Non-Linearity
+25°C
0°C to +70°C
–55°C to +125°C
Full Scale Absolute Accuracy
+25°C
0°C to +70°C
–55°C to +125°C
Unipolar Zero Error
†
0°C to +70°C
–55°C to +125°C
Bipolar Zero Error
†
0°C to +70°C
–55°C to +125°C
Bipolar Offset Error
†
0°C to +70°C
–55°C to +125°C
Gain Error
†
0°C to +70°C
–55°C to +125°C
Internal Reference Voltage,
+25°C
Drift
External Current
MIN.
—
—
4.5
—
TYP.
±5
0 to +10
5
6
MAX.
—
—
—
15
UNITS
Volts
Volts
kW
pF
—
8
6
—
—
—
—
—
—
160
–68
10
8
±150
—
—
—
—
—
250
–65
—
—
—
20
16
15
±50
1000
280
dB
MHz
MHz
V/μs
ns
ns
ps
ps
ns
ns
DIGITAL INPUTS
+2.0
—
—
—
—
—
—
—
12 Bits
Over the operating temperature range
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
+9.98
—
—
±1/4
±1/4
±1/2
±1/4
±1/4
±1/2
±0.13
±0.15
±0.25
±0.074
±0.224
±0.074
±0.124
±0.1
±0.3
±0.1
±0.3
+10.0
±5
—
±3/4
±3/4
±1.5
±3/4
±3/4
±1
±0.25
±0.44
±0.78
±0.265
±0.43
±0.166
±0.210
±0.38
±0.60
±0.38
±0.60
+10.02
±30
1.5
LSB
LSB
LSB
LSB
LSB
LSB
%FSR
%FSR
%FSR
%FSR
%FSR
%FSR
%FSR
%FSR
%FSR
%
%
Volts
ppm/°C
mA
—
+0.8
+10
-600
Volts
Volts
μA
μA
PERFORMANCE
1
1
1
—
—
—
—
—
—
MHz
MHz
MHz
DIGITAL OUTPUTS
Straight binary/Offset binary
Complementary binary
Complementary offset binary
+2.4
—
—
—
—
—
—
—
—
+0.4
–160
+6.4
Volts
Volts
μA
mA
POWER REQUIREMENTS
+14.25
–14.25
+4.75
—
—
—
—
—
+15.0
–15.0
+5.0
+24
–40
+80
1.3
—
+15.75
–15.75
+5.25
+35
–48
+95
1.7
±0.07
Volts
Volts
Volts
mA
mA
mA
Watts
%FSR%V
PHYSICAL/ENVIRONMENTAL
0
—
+70
°C
–55
—
+125
°C
–65
—
+150
°C
24-pin, metal-sealed, ceramic DDIP
0.42 ounces (12 grams)
DYNAMIC PERFORMANCE
In-Band Harmonics
(–0.5dB)
dc to 100kHz
—
–81
100kHz to 500kHz
—
–75
Total Harm. Distort.
(–0.5dB)
dc to 100kHz
—
–78
100kHz to 500kHz
—
–73
† See Tech Note 1
–75
–70
–75
–68
dB
dB
dB
dB
Full Scale Amplitude
(SNR + Distortion) – 1.76 + 20 log
6.02
Actual Input Amplitude
➂
For ±12V, +5V operation, contact DATEL
www.murata-ps.com
Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
MDA_ADS-112.B01
Page 2 of 6
ADS-112
12-Bit, 1MHz, Low-Power Sampling A/D Converters
TECHNICAL NOTES
1. Applications which are unaffected by endpoint errors or remove them through software will
use the typical connections shown in Figure 3. Remove system errors or adjust the small initial
errors of the ADS-112 to zero using the optional external circuitry shown in Figure 4. The
external adjustment circuit has no effect on the throughput rate.
2. For best performance, always connect the analog and digital ground pins to a ground plane
beneath the converter. The analog and digital grounds are not connected to each other inter-
nally.
3. Bypass the analog and digital supplies and the +10V reference (pin 21) to ground with 4.7μF,
25V tantalum electrolytic capacitors in parallel with 0.1μF ceramic capacitors. Bypass the +10V
reference (pin 21) to analog ground (pin 23).
4. Obtain straight binary/offset binary output coding by tying COMP BIN (pin 18) 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 pin 18 to ground. The pin 18 signal is compat-
ible with CMOS/TTL logic levels for those users desiring dynamic control of this function.
5. To enable the three-state outputs, connect ENABLE (pin 17) to a logic "0" (low). To disable,
connect pin 17 to a logic "1" (high).
6. Do not change the status of pin 18 when EOC is high.
7. Re-initiating the START CONVERT (pin 16) while EOC is a logic "1" (high) will result in a new
conversion sequence.
TIMING
Figure 2 shows the relationship between the various input signals. The timing shown applies
over the operating temperature range and over the operating power supply range. These times
are guaranteed by design.
N
START
CONVERT
150ns, ±25ns
N+1
10ns min.
20ns max.
INTERNAL S/H
Hold
Acquisition Time
250ns
20ns max.
EOC
Conversion Time
600ns max.
60ns max.
35ns max.
OUTPUT
DATA
DATA N-1 VALID
800ns min.
INVALID
DATA
200ns max.
DATA N VALID
INVALID
DATA
Note: Scale is approximately 50ns per division.
Figure 2. ADS-112 Timing Diagram
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Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
MDA_ADS-112.B01
Page 3 of 6
ADS-112
12-Bit, 1MHz, Low-Power Sampling A/D Converters
CALIBRATION PROCEDURE
1.
Connect the converter per Figures 3 and 4 and Tables 1 and 3 for the
appropriate input range. Apply a pulse of 150 nanoseconds to the START
CONVERT input (pin 16) at a rate of 250kHz. This rate is chosen to reduce
the flicker if LED’s are used on the outputs for calibration purposes.
2. Zero Adjustments
Apply a precision voltage reference source between the amplifier’s analog
input and ground. Adjust the output of the reference source per Table 2.
For unipolar, adjust the zero trimming potentiometer so that the output
code flickers equally between 0000 0000 0000 and 0000 0000 0001 with
COMP BIN (pin 18) tied high (straight binary) or between 1111 1111 1111
and 1111 1111 1110 with pin 18 tied low (complementary binary).
For bipolar operation, adjust the potentiometer such that the code flick-
ers equally between 1000 0000 0000 and 1000 0000 0001 with pin 18
tied high (offset binary) or between 0111 1111 1111 and 0111 1111
1110 with pin 18 tied low (complementary offset binary).
3. Full-Scale Adjustment
Set the output of the voltage reference used in step 2 to the value shown
in Table 2. Adjust the gain trimming potentiometer so that the output
code flickers equally between 1111 1111 1110 and 1111 1111 1111 for
pin 18 tied high or between 0000 0000 0001 and 0000 0000 0000 for
pin 18 tied low.
To confirm proper operation of the device, vary the precision reference
voltage source to obtain the output coding listed in Table 4.
Table 1. Input Range Selection
Input Range
±5v
0 to +10V
Input Pin
Pin 19
Pin 19
Tie Together
Pin 20 to Pin 21
Pin 20 to Ground
Input Range
0 to +10V
±5V
SIGNAL
INPUT
R2
+15V
R1
To Pin19
of ADS-112
–15V
5k
50
GAIN
ADJUST
5k
10k
ZERO/
OFFSET
ADJUST
For values of R1 and R2 refer to Table 3.
Figure 4. Optional Calibration Circuit
Table 2. Zero and Gain Adjust
Zero Adjust
+1/2 LSB
+1.22mV
+1.22mV
Gain Adjust
+FS – 1 1/2 LSB
+9.9963V
+4.9963V
Table 3. Input Range (using external calibration)
Input Range
0 to 10V, ±5
0 to 5V, ±2.5V
0 to +2.5V, ±1.25V
R1
2
2
2
R2
2
6
14
Unit
kW
kW
kW
BIPOLAR
OPERATION
20
21
UNIPOLAR
OPERATION
20
21 +10V REF.
+
0.1F
4.7F
–15V
4.7F
4.7F
+15V
+5V
4.7F
+
0.1F
+
0.1F
24
ADS-112
23
22
13
12 BIT 1 (MSB)
11 BIT 2
10 BIT 3
9 BIT 4
8 BIT 5
7 BIT 6
6 BIT 7
5 BIT 8
4 BIT 9
3 BIT 10
2 BIT 11
1 BIT 12 (LSB)
15 EOC
17 ENABLE (1-12)
16 START CONVERT
19 ANALOG INPUT
+
0.1F
14
COMP BIN 18
Note: Always bypass pin 21 to ground
+5V
Figure 3. Typical ADS-112 Connection Diagram
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Technical enquiries
email: sales@murata-ps.com, tel:
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MDA_ADS-112.B01
Page 4 of 6
ADS-112
12-Bit, 1MHz, Low-Power Sampling A/D Converters
Table 4. Output Coding
STRAIGHT BIN.
UNIPOLAR
SCALE
+FS – 1 LSB
+7/8 FS
+3/4 FS
+1/2 FS
+1/4 FS
+1/8 FS
+1 LSB
0
INPUT RANGE
0 to +10V
+9.9976
+8.7500
+7.5000
+5.0000
+2.5000
+1.2500
+0.0024
0.0000
COMP. BINARY
INPUT RANGE
±5V
+4.9976
+3.7500
+2.5000
0.0000
–2.5000
–3.7500
–4.9976
–5.0000
BIPOLAR
SCALE
+FS –1 LSB
+3/4FS
+1/2FS
0
–1/2FS
–3/4FS
–FS+1LSB
–FS
OUTPUT CODING
MSB
1111
1110
1100
1000
0100
0010
0000
0000
LSB
1111
0000
0000
0000
0000
0000
0000
0000
1111
0000
0000
0000
0000
0000
0001
0000
MSB
0000
0001
0011
0111
1011
1101
1111
1111
0000
1111
1111
1111
1111
1111
1111
1111
LSB
0000
1111
1111
1111
1111
1111
1110
1111
OFF. BINARY
COMP. OFF. BIN.
0
–10
Amplitude Relative to Full Scale (dB)
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
–120
–130
0
50
100
150
200
250
300
350
400
450
500
Frequency (kHz)
(fs = 1MHz, fin = 485kHz, Vin = –0.5dB, 4,096-point FFT)
Figure 5. FFT Analysis of ADS-112
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Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
MDA_ADS-112.B01
Page 5 of 6
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