DATEL ADS-951MM, ADS-951MC, ADS-B951 Datasheet

FEATURES

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• 18-bit resolution

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• 1MHz minimum sampling rate

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• No missing codes over full military temperature range

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• Very low power, 1.45 Watts

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• Small, 32-pin, side-brazed, ceramic TDIP

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• Edge-triggered

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• Excellent performance

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• Ideal for both time and frequency-domain applications

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• Low cost

operating temperature ranges. A proprietary, auto-calibrating,
error-correcting circuit enables the device to achieve specified
performance over the full military temperature range.

PRELIMINARY PRODUCT DATA

ADS-951

18-Bit, 1MHz, Low-Power

Sampling A/D Converters

GENERAL DESCRIPTION

The low-cost ADS-951 is an 18-bit, 1MHz sampling A/D
converter. This device accurately samples full-scale input
signals up to Nyquist frequencies with no missing codes. This
feature, combined with excellent signal-to-noise ratio (SNR)
and total harmonic distortion (THD), makes the ADS-951 the
ideal choice for both time-domain (medical imaging, scanners,
process control) and frequency-domain (radar, telecommunica­tions, spectrum analysis) applications.

Packaged in a 32-pin, side-brazed, metal-sealed, ceramic
TDIP, the functionally complete ADS-951 contains a fast­settling sample-hold amplifier, a subranging (two-pass) A/D
converter, an internal reference, timing/control logic, and error­correction circuitry. Digital input and output levels are TTL, and
the ADS-951 only requires the rising edge of the start convert
pulse to operate.

Requiring ±15V and ±5V supplies, the ADS-951 typically
dissipates 1.45 Watts. The device is offered with a bipolar
(±5V) analog input range. Models are available for use in
either commercial (0 to +70°C) or military (–55 to +125°C)

INPUT/OUTPUT CONNECTIONS

Figure 1. ADS-951 Functional Bloc k Diagram

1 BIT 2 32 BIT 3
2 BIT 1 (MSB) 31 BIT 4
3 ANALOG GROUND 30 BIT 5
4 ANALOG INPUT 29 BIT 6
5 +5V REFERENCE OUT 28 BIT 7
6 GAIN ADJUST 27 BIT 8
7 COMPENSATION 26 BIT 9
8 –15V SUPPLY 25 BIT 10

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

PIN FUNCTION PIN FUNCTION

DATEL, Inc., Mansfield, MA 02048 ( USA) • Tel: [phone] Fax: [phone] • Email: [e-mail] • Internet: www.datel.com

®®

REF

DAC

2 BIT 1 (MSB)
1 BIT 2
32 BIT 3
31 BIT 4
30 BIT 5
29 BIT 6
28 BIT 7
27 BIT 8
26 BIT 9
25 BIT 10
24 BIT 11
23 BIT 12
22 BIT 13
21 BIT 14
20 BIT 15
19 BIT 16
18 BIT 17
17 BIT 18 (LSB)

TIMING AND

CONTROL LOGIC

ANALOG INPUT 4

START CONVERT 16

EOC 15

–

+

S/H

BUFFER

DIGITAL CORRECTION LOGIC

FLASH

ADC

1

FLASH

ADC

2

5

AMP

GAIN

CIRCUIT

COMPENSATION 7

+

5V REFERENCE OUT 5

10

+5V ANALOG

SUPPLY

11

–5V ANALOG

SUPPLY

3, 12

ANALOG

GROUND

14

+5V DIGITAL

SUPPLY

9

+15V

SUPPLY

8

–15V

SUPPLY

13

DIGITAL

GROUND

GAIN ADJUST 6

ADS-951

2

®®

+25°C 0 to +70°C –55 to +125°C

ANALOG INPUT MIN. TYP. MAX. MIN. TYP. MAX. MIN. TYP. MAX. UNITS

Input V oltage Range

➁

— ±5 ——±5 ——±5 — Volts

Input Resistance — 500 ——500 ——500 —

Ω

Input Capacitance — 715— 715— 715pF

DIGITAL INPUT

Logic Levels

Logic "1" +2.0 ——+2.0 ——+2.0 ——Volts
Logic "0" ——+0.8 ——+0.8 ——+0.8 Volts
Logic Loading "1" ——+20 ——+20 ——+20 µA
Logic Loading "0" ——–20 ——–20 ——–20 µA

Start Convert Positive Pulse Width

➂

20 500 — 20 500 — 20 500 — ns

STATIC PERFORMANCE

Resolution — 18 ——18 ——18 — Bits
Integral Nonlinearity (fin = 10kHz) — ±0.75 ——±1.5 ——±2 — LSB
Differential Nonlinearity (fin = 10kHz) –0.95 ±0.5 +1 –0.95 ±0.5 +1 –0.95 ±0.50 +1.25 LSB
Full Scale Absolute Accuracy — ±0.1 ±0.25 — ±0.25 ±0.4 — ±0.4 ±0.8 %FSR
Bipolar Zero Error (Tech Note 2) — ±0.1 ±0.15 — ±0.15 ±0.25 — ±0.25 ±0.5 %FSR
Bipolar Offset Error (Tech Note 2) — ±0.1 ±0.2 — ±0.2 ±0.3 — ±0.3 ±0.6 %FSR
Gain Error (Tech Note 2) — ±0.1 ±0.25 — ±0.25 ±0.4 — ±0.4 ±0.9 %
No Missing Codes (fin = 10kHz) 18 ——18 ——18 ——Bits

DYNAMIC PERFORMANCE

Peak Harmonics (–0.5dB)

dc to 100kHz —–90 ——–90 ——–86 — dB
100kHz to 500kHz —–89 ——–89 ——–85 — dB

Total Harmonic Distortion (–0.5dB)

dc to 100kHz —–89 ——–89 ——–85 — dB
100kHz to 500kHz —–88 ——–88 ——–84 — dB

Signal-to-Noise Ratio

(w/o distortion, –0.5dB)
dc to 100kHz — 89 ——89 ——86 — dB
100kHz to 500kHz — 88 ——88 ——85 — dB

Signal-to-Noise Ratio

➃

(& distortion, –0.5dB)
dc to 100kHz — 86 ——86 ——82 — dB
100kHz to 500kHz — 84 ——84 ——81 — dB

Noise — 25 ——25 ——25 — µVrms
Two-Tone Intermodulation

Distortion (fin = 100kHz,

240kHz, fs = 1MHz, –0.5dB) —–85 ——–85 ——–85 — dB

Input Bandwidth (–3dB)

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

Feedthrough Rejection (fin = 500kHz) — 84 ——84 ——84 — dB
Slew Rate — TBD ——TBD ——TBD — V/µs
Aperture Delay Time — +20 ——+20 ——+20 — ns
Aperture Uncertainty — 5 ——5 —— 5 — ps rms
S/H Acquisition Time

( to ±0.003%FSR, 10V step) — 260 ——260 ——260 — ns

Overvoltage Recovery Time

➄

— 500 ——500 ——500 — ns

A/D Conversion Rate 1 —— 1 —— 1 ——MHz

PARAMETERS LIMITS UNITS
+15V Supply (Pin 9) 0 to +16 Volts

–15V Supply (Pin 8) 0 to –16 Volts
+5V Supply (Pins 10, 14) 0 to +6 Volts
–5V Supply (Pin 11) 0 to –6 Volts
Digital Input (Pin 16) –0.3 to +V

DD +0.3 Volts

Analog Input (Pin 4) ±15 Volts
Lead Temperature (10 seconds) +300 °C

P ARAMETERS MIN. TYP. MAX. UNITS
Operating Temp. Range, Case

ADS-951MC 0 — +70 °C
ADS-951MM –55 — +125 °C

Thermal Impedance

θ

jc — 5 —°C/Watt

θ

ca — 22 —°C/Watt

Storage Temperature Range –65 — +150 °C
Package T ype 32-pin,side-braz ed, metal-sealed, ceramic TDIP

Weight 0.46 ounces (13 grams)

ABSOLUTE MAXIMUM RATINGS

PHYSICAL/ENVIRONMENTAL

FUNCTIONAL SPECIFICATIONS

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