DATEL's ADS-117 is a functionally complete, 12-bit, 2MHz,
sampling A/D converter. Its standard, 24-pin, double-width
DIP contains a fast-settling sample-hold amplifier, a 12-bit
subranging (two-step) 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. Digital
input and output levels are TTL.
Total harmonic distortion (THD) and signal-to-noise ratio
(including distortion) typically run –78dB and 70dB,
respectively, with full scale inputs up to 100kHz. The ADS-117
requires ±15V and +5V power supplies and typically
consumes 1.6 Watts. Models are available for use in either
commercial (0 to +70°C) or military (–55 to +125°C) operating
temperature ranges.
0°C to +70°C—±1/2±0.95LSB
–55°C to +125°C—±1+1.5LSB
Full Scale Absolute Accuracy
(see Tech Note 1)
0°C to +70°C—±0.13±0.44%FSR
–55°C to +125°C—±0.25±0.73%FSR
Unipolar/Bipolar Zero Error
0°C to +70°C (see Tech Note 1)—±0.07±0.27%FSR
–55°C to +125°C—±0.22±0.73%FSR
Bipolar Offset Error
0°C to +70°C (see Tech Note 1)—±0.1±0.38%FSR
–55°C to +125°C—±0.53±0.73%FSR
Gain Error (see Tech Note 1)
0°C to +70°C—±0.1±0.38%
–55°C to +125°C—±0.53±0.73%
Internal Reference Voltage
0°C to +70°C+9.97+10.0+10.03Volts
–55°C to +125°C+9.95—+10.05Volts
External Current——1.5mA
DYNAMIC PERFORMANCE
Spurious Free Dynamic
Range (–0.5dB) ➁
dc to 100kHz—–81—dB
100kHz to 500kHz—–75–70dB
500kHz to 1MHz—–70—dB
Total Harm. Distort. (–0.5dB)
dc to 100kHz—–78—dB
100kHz to 500kHz—–73–68dB
500kHz to 1MHz—–71—dB
Input Bandwith (–3dB)
Small Signal (–20dB input)810—MHz
Large Signal (–0.5dB input)79—MHz
Feedthrough (1MHz)–72–74—dB
➀ See Table 1 also
➁ Same specifications for in-band harmonics.
DYNAMIC PERF. (cont)MIN.TYP.MAX.UNITS
SNR (wo/distortion, –0.5dB)
dc to 100kHz
0°C to +70°C—72—dB
–55°C to +125°C—72—dB
100kHz to 500kHz
0°C to +70°C6570—dB
–55°C to +125°C6570—dB
500kHz to 1MHz
0°C to +70°C—70—dB
–55°C to +125°C—70—dB
SNR (and distort., –0.5dB) ➂
dc to 100kHz
0°C to +70°C—70—dB
–55°C to +125°C—69—dB
100kHz to 500kHz
0°C to +70°C6470—dB
–55°C to +125°C6269—dB
500kHz to 1MHz
0°C to +70°C—69—dB
–55°C to +125°C—69—dB
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-117 to zero using the
optional external circuitry shown in Figure 4. The external
adjustment circuit has no effect on the throughput rate.
2. Always connect the analog and digital grounds to a ground
plane beneath the converter for best performance. The
analog and digital grounds are not connected to each other
internally.
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
ADS-117
output coding, tie pin 18 to ground. The pin 18 signal is
compatible with CMOS/TTL logic levels for those users
desiring dynamic control of this function. Do not change
COMP BIN status while EOC is high.
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. To meet the guaranteed conversion rate, a maximum start
convert pulse is specified. A wider start convert pulse will
result in slower conversion rates. An initial start convert
pulse is required before performing an actual conversion
after power-up to assure the sample-hold is in the acquisition mode.
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.
7. Re-initiating the START CONVERT (pin 16) while EOC is a
logic "1" (high) will result in a new conversion sequence.
START
CONVERT
INTERNAL S/H
EOC
OUTPUT
DATA
NN+1
50ns typ.,
30ns min., 60ns max.
10ns min.
25ns max.
Hold
10ns min.
17ns max.
Conversion Time
325ns typ.
DATA N-1 VALID
350ns min.
Figure 2. ADS-117 Timing Diagram
Acquisition Time
165ns typ.
170ns max.
60ns max.
35ns max.
INVALID
DATA
150ns max.
DATA N VALID
INVALID
DATA
3
Page 4
ADS-117
For values of R1 and R2 refer to Table 1.
➀
CONVERT
and bipolar operation.
®®
CALIBRATION PROCEDURE
1. Connect the converter per Figure 3, Figure 4, and Table 1
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 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
the pin 18 tied high (straight binary) or between 1111 1111
1111 and 1111 1111 1110 with the pin 18 tied low (complementary binary).
For bipolar operation, adjust the potentiometer such that the
code flickers 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 1. 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.
4. To confirm proper operation of the device, vary the precision
reference voltage source to obtain the output coding listed
in Table 3.
2 place decimal (.XX) ±0.010 (±0.254)
3 place decimal (.XXX) ±0.005 (±0.127)
Lead Material:
Lead Finish: 50 microinches (minimum) gold plating
over 100 microinches (nominal) nickel plating
(unless otherwise indicated):
Kovar alloy
+0.002
0.010
–0.001
0.190 MAX.
(4.826)
0.018 ±0.002
(0.457)
0.100
(2.540)
(1.016)
0.040
SEATING
PLANE
0.025
(0.635)
(0.254)
0.600 ±0.010
(15.240)
0.100
(2.540)
ORDERING INFORMATION
MODEL NUMBEROPERATING TEMP. RANGE
ADS-117MC0 to +70°C
ADS-117MM–55 to +125°C
ADS-117/883–55 to +125°C
For MIL-STD-883 product specification or availability of surface-mount packaging, contact DATEL. Receptacles for PC mounting
can be ordered through AMP Inc., Part # 3-331272-8 (Component Lead Socket), 24 required.
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:sales@datel.com
Data Sheet Fax Back: (508) 261-2857
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.
ISO 9001
DS-0230E05/98
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
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