DATEL ADS-112 Service Manual

® ®

REGISTERREGISTER

3-STATE OUTPUT REGISTER

START CONVERT 16

DIGITAL CORRECTION LOGIC

+5V SUPPLY

+15V SUPPLY

ANALOG GROUND

DIGITAL GROUND

–15V SUPPLY

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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

ADS-112

12-Bit, 1MHz, Low-Power

Sampling A/D Converters

GENERAL DESCRIPTION

DATEL’s ADS-112 is a 12-bit, functionally complete, 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 frequencies. Models
are available for use in either commercial (0 to + 70°C) or
military (–55 to +125°C) operating temperature ranges.

Typical applications include spectrum, transient, vibration and
waveform analysis. This device is also ideally suited for radar,
sonar, video digitization, medical instrumentation and high­speed data acquisition systems.

+10V REF. 21

S2

S/H

S1

BUFFER

BIPOLAR 20

ANALOG INPUT 19

–
+

INPUT/OUTPUT CONNECTIONS

PIN FUNCTION PIN FUNCTION

1 BIT 12 (LSB) 24 –15V SUPPLY
2 BIT 11 23 ANALOG GROUND
3 BIT 10 22 +15V SUPPLY
4 BIT 9 21 +10V REFERENCE
5 BIT 8 20 BIPOLAR
6 BIT 7 19 ANALOG INPUT
7 BIT 6 18 COMP BIN
8 BIT 5 17 ENABLE (1-12)

9 BIT 4 16 START CONVERT
10 BIT 3 15 EOC
11 BIT 2 14 DIGITAL GROUND
12 BIT 1 (MSB) 13 +5V SUPPLY

DAC

REF

FLASH

ADC

17 ENABLE (1-12)

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)

COMP BIN 18

EOC 15

TIMING AND

CONTROL LOGIC

13

14

22

23

24

Figure 1. ADS-112 Functional Block Diagram

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

ADS-112

® ®

ABSOLUTE MAXIMUM RATINGS

PARAMETERS LIMITS UNITS

+15V Supply (Pin 22) 0 to +18 Volts
–15V Supply (Pin 24) 0 to –18 Volts
+5V Supply (Pin 13) 0 to +6 Volts
Digital Inputs (Pin 16, 17, 18) –0.3 to +V

DD +0.3 Volts

Analog Input (Pin 19) –9 to +15 Volts
Lead Temp. (10 seconds) +300 °C

FUNCTIONAL SPECIFICATIONS

(TA = +25°C, ±VCC = ±15V, +VDD =+5V, 1MHz sampling rate, and a minimum 1 minute
warmup unless otherwise specified.)

ANALOG INPUTS MIN. TYP. MAX. UNITS

Input Voltage Range ➀

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

Input Impedence 4.5 5 — kΩ
Input Capacitance — 6 15 pF

DIGITAL INPUTS

Logic Levels

Logic "1" +2.0 — — Volts
Logic "0" — — +0.8 Volts
Logic Loading "1" — — +10 µA
Logic Loading "0" — — –600 µA

PERFORMANCE

Resolution 12 Bits
No Missing Codes

in = 1MHz) Over the operating temperature range

(12 Bits; f

Integral Non-Linearity

+25°C — ±1/4 ±3/4 LSB
0°C to +70°C — ±1/4 ±3/4 LSB
–55°C to +125°C — ±1/2 ±1.5 LSB

Differential Non-Linearity

+25°C — ±1/4 ±3/4 LSB
0°C to +70°C — ±1/4 ±3/4 LSB
–55°C to +125°C — ±1/2 ±1 LSB

Full Scale Absolute Accuracy

+25°C — ±0.13 ±0.25 %FSR
0°C to +70°C — ±0.15 ±0.44 %FSR
–55°C to +125°C — ±0.25 ±0.78 %FSR

Unipolar Zero Error †

0°C to +70°C — ±0.074 ±0.265 %FSR
–55°C to +125°C — ±0.224 ±0.43 %FSR

Bipolar Zero Error †

0°C to +70°C — ±0.074 ±0.166 %FSR
–55°C to +125°C — ±0.124 ±0.210 %FSR

Bipolar Offset Error †

0°C to +70°C — ±0.1 ±0.38 %FSR
–55°C to +125°C — ±0.3 ±0.60 %FSR

Gain Error †

0°C to +70°C — ±0.1 ±0.38 %
–55°C to +125°C — ±0.3 ±0.60 %

Internal Reference Voltage, +25°C +9.98 +10.0 +10.02 Volts

Drift — ±5 ±30 ppm/°C
External Current — — 1.5 mA

DYNAMIC PERFORMANCE

In-Band Harmonics (–0.5dB)

dc to 100kHz — –81 –75 dB
100kHz to 500kHz — –75 –70 dB

Total Harm. Distort. (–0.5dB)

dc to 100kHz — –78 –75 dB
100kHz to 500kHz — –73 –68 dB

† See Tech Note 1

DYNAMIC PERF. (cont) MIN. TYP. MAX. UNITS

Signal-to-Noise Ratio

(wo/distort., –0.5dB)
dc to 100kHz 68 72 — dB
100kHz to 500kHz 67 71 — dB

Signal-to-Noise Ratio ➁

(& distort., –0.5dB)
dc to 100kHz 66 70 — dB
100kHz to 500kHz 66 70 — dB

Two-tone Intermodulation
Distortion (f

in = 75kHz,

s = 1MHz, –0.7dB) — –88 –80 dB

105kHz, f

Two-tone Intermodulation
Distortion (f

in = 480kHz,

s = 1MHz, –0.7dB) — –68 –65 dB

490kHz, f

Input Bandwith (–3dB)

Small Signal (–20dB input) 8 10 — MHz
Large Signal (–0.5dB input) 6 8 — MHz

Slew Rate — ±150 — V/µs
Apperture Delay TIme — — 20 ns
Effect. Aperture Delay Time — — 16 ns
Apperture Uncertainity (Jitter)

RMS — — 15 ps
Peak — — ±50 ps

Overvoltage Recovery Time — — 1000 ns
S/H Acquisition Time 160 250 280 ns
Conversion Rate

(Changing Inputs)
+25°C 1 — — MHz
0°C to +70°C 1 — — MHz
–55°C to +125°C 1 — — MHz

DIGITAL OUTPUTS

Output Coding

Pin 18 High
Pin 18 Low

Logic Level

Staight binary/Offset binary

Complementary binary

Complementary offset binary

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

POWER REQUIREMENTS

Power Supply Ranges ➂

+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 Current

+15V Supply — +24 +35 mA
–15V Supply — –40 –48 mA
+5V Supply — +80 +95 mA

Power Dissipation — 1.3 1.7 Watts
Power Supply Rejection — — ±0.07 %FSR%V

PHYSICAL/ENVIRONMENTAL

Operating Temp. Range, Case

ADS-112MC 0 — +70 °C
ADS-112MM, 883 –55 — +125 °C

Storage Temperature Range –65 — +150 °C
Package Type 24-pin, metal-sealed, ceramic DDIP

Weight 0.42 ounces (12 grams)

➀ See Table 3 also
➁ Effective bits is equal to:

(SNR + Distortion) – 1.76 + 20 log

Full Scale Amplitude

Actual Input Amplitude

6.02

➂ For ±12V, +5V operation, contact DATEL

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