DATEL ADS-942MC, ADS-942ME Datasheet

® ®

REGISTERREGISTER

DIGITAL CORRECTION LOGIC

GROUND

GROUND

SUPPLY

3-STATE OUTPUT REGISTER

SUPPLY

GROUND

SELECT

SUPPLY

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

ADS-942

14-Bit, 2MHz

Sampling A/D Converters

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.

+10V REF. OUT 1

OFFSET ADJUST 5

BIPOLAR 2

ANALOG INPUT 3

START CONVERT 32

EOC 16

OFFSET
CIRCUIT

S/H

TIMING AND

CONTROL LOGIC

S2

S1

BUFFER

REF

FLASH

ADC

INPUT/OUTPUT CONNECTIONS

PIN FUNCTION PIN FUNCTION

1 +10V REF. OUT 32 START CONVERT
2 BIPOLAR 31 BIT 1 OUT (MSB)
3 ANALOG INPUT 30 BIT 1 OUT (MSB)
4 SIGNAL GROUND 29 BIT 2 OUT
5 OFFSET ADJUST 28 BIT 3 OUT
6 ANALOG GROUND 27 BIT 4 OUT
7 OVERFLOW 26 BIT 5 OUT
8 CODING SELECT 25 BIT 6 OUT

9 ENABLE 24 BIT 7 OUT
10 +5V SUPPLY 23 BIT 8 OUT
11 DIGITAL GROUND 22 BIT 9 OUT
12 +15V SUPPLY 21 BIT 10 OUT
13 –15V SUPPLY 20 BIT 11 OUT
14 ANALOG GROUND 19 BIT 12 OUT
15 ANALOG GROUND 18 BIT 13 OUT
16 EOC 17 BIT 14 OUT (LSB)

DAC

31 BIT 1 OUT (MSB)
30 BIT 1 OUT (MSB)
29 BIT 2 OUT
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)

9 ENABLE
7 OVERFLOW

4

SIGNAL

10

+5V

11

DIGITAL

12

+15V

6, 14, 15
ANALOG

13

–15V

8

CODING

Figure 1. ADS-942 Functional Block Diagram

DATEL, Inc., 11 Cabot Boulevard, Mansfield, MA 02048-1151 (U.S.A.) • Tel: [phone] Fax: [phone] • For immediate assistance: [phone]

ADS-942

® ®

ABSOLUTE MAXIMUM RATINGS

PARAMETERS LIMITS UNITS

+15V Supply (Pin 12) 0 to +16 Volts
–15V Supply (Pin 13) 0 to –16 Volts
+5V Supply (Pin 10) 0 to +6 Volts
Digital Inputs (Pin 8,9, 32) –0.3 to +V

DD +0.3 Volts

Analog Input (Pin 3) ±15 Volts
Lead Temp. (10 seconds) +300 °C

FUNCTIONAL SPECIFICATIONS

(TA = +25°C, ±VCC = ±15V, +VDD = +5V, 2MHz sampling rate, and a minimum 7 minute
warmup unless otherwise specified.)

ANALOG INPUTS MIN. TYP. MAX. UNITS

Input Voltage Range

Unipolar — 0 to +10 — Volts
Bipolar — ±5 — Volts

Input Impedence 4.9 5 — kΩ
Input Capacitance — 7 15 pF

DIGITAL INPUTS

Logic Levels

Logic "1" +2.0 — — Volts
Logic "0" — — +0.8 Volts
Logic Loading "1" — — +5 µA
Logic Loading "0" — — –600 µA

PERFORMANCE

Integral Non-Linearity

in = 1MHz)

(f

+25°C — ±1 ±2 LSB
0 to +70°C — ±1 ±2 LSB
–40 to +85°C — ±2 ±3 LSB

Differential Non-Linearity

in = 1MHz)

(f

+25°C –0.75 ±0.5 ±0.75 LSB
0 to +70°C –0.95 ±0.75 ±1.25 LSB
–40 to +85°C –1 ±1 +2.5 LSB

Full Scale Absolute Accuracy

+25°C — ±0.1 ±0.122 %FSR
0 to +70°C — ±0.12 ±0.36 %FSR
–40 to +85°C — ±0.45 ±0.85 %FSR

Unipolar Zero Error

+25°C (see Figure 3) — ±0.05 ±0.122 %FSR
0 to +70°C — ±0.1 ±0.2 %FSR
–40 to +85°C — ±0.2 ±0.3 %FSR

Bipolar Zero Error

+25°C (see Figure 3) — ±0.05 ±0.122 %FSR
0 to +70°C — ±0.1 ±0.2 %FSR
–40 to +85°C — ±0.2 ±0.3 %FSR

Bipolar Offset Error

+25°C (see Figure 3) — ±0.1 ±0.2 %FSR
0 to +70°C — ±0.12 ±0.3 %FSR
–40 to +85°C — ±0.5 ±0.8 %FSR

Gain Error

+25°C (see Figure 3) — ±0.018 ±0.122 %
0 to +70°C — ±0.12 ±0.3 %
–40 to +85°C — ±0.6 ±0.8 %

No Missing Codes (f

14 Bits 0 to +70°C
13 Bits –40 to +85°C

Resolution 14 Bits

in = 500kHz)

OUTPUTS MIN. TYP. MAX. UNITS

Output Coding Staight Bin./Offset Bin./2's Comp.

Comp. Bin./Comp. Offset Bin./C2C

Logic Level

Logic "1" +2.4 — — Volts
Logic "0" — — +0.4 Volts
Logic Loading "1" — — –160 µA
Logic Loading "0" — — +6.4 mA

Internal Reference

Voltage, +25°C +9.98 +10.0 +10.02 Volts
Drift — ±13 ±30 ppm/°C
External Current — — 5 mA

DYNAMIC PERFORMANCE

Total Harm. Distort. (–0.5dB)

dc to 100kHz — –85 –76 dB
100kHz to 500kHz — –80 –75 dB
500kHz to 1MHz — –77 — dB

Signal-to-Noise Ratio

(w/o distortion, –0.5dB
dc to 100kHz 74 78 — dB
100kHz to 500kHz 73 75 — dB
500kHz to 1MHz — 73 — dB

Signal-to-Noise Ratio

(and distortion, –0.5dB)
dc to 100kHz 73 78 — dB
100kHz to 500kHz 72 75 — dB
500kHz to 1MHz — 72 — dB

Spurious Free Dyn. Range ➀

dc to 100kHz — –86 –77 dB
100 to 500kHz — –81 –75 dB
500kHz to 1MHz — –78 — dB

Two-tone IMD
Distortion (f

in = 100kHz,

240kHz, fs = 2.0Mhz,
–0.5dB) –85 — — dB

Input Bandwidth (–3dB)

Small Signal (–20dB input) — 6 — MHz
Large Signal (–0.5dB input) — 1.75 — MHz

Slew Rate — ±250 — V/µs
Aperture Delay Time — — ±10 ns
Aperature Uncertainty — — 5 ps, ms
S/H Acq. Time, (to ±0.003%FSR)

Sinusoidal (f

in = 1MHz) — 120 150 ns

Step input — 250 450 ns

Conversion Rate

Sinusoidal (f

in = 1MHz) 2 — — MHz

Step input 1.3 — — MHz

Feedthrough Rejection

in = 1MHz) — 85 — dB

(f

Overvoltage Recovery, ±12V — 1000 2000 ns
Noise — 250 — µVrms

POWER REQUIREMENTS

Power Supply Ranges

+15V Supply +14.25 +15.0 +15.75 Volts
–15V Supply –14.25 –15.0 –15.75 Volts
+5V Supply +4.75 +5.0 +5.25 Volts

Power Supply Currents

+15V Supply — +65 +87 mA
–15V Supply — –80 –98 mA
+5V Supply — +150 +165 mA

Power Dissipation — 2.9 3.4 Watts
Power Supply Rejection — — ±0.02 %FSR%V

PHYSICAL/ENVIRONMENTAL

Footnote:

➀ Same specification as In-Band Harmonics and Peak Harmonics.

Operating Temp. Range, Case

ADS-942MC 0 — +70 °C
ADS-942ME –40 — +85 °C

Storage Temperature Range –65 — +150 °C
Package Type 32-pin, metal-sealed, ceramic TDIP

Weight 0.46 ounces (13 grams)

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