DATEL ADS-933MM, ADS-933MC, ADS-B933 Datasheet

PIN FUNCTION PIN FUNCTION

1 +3.2V REF. OUT 40 NO CONNECTION
2 UNIPOLAR 39 NO CONNECTION
3 ANALOG INPUT 38 +5V ANALOG SUPPLY
4 ANALOG GROUND 37 –5V SUPPLY
5 OFFSET ADJUST 36 ANALOG GROUND
6 GAIN ADJUST 35 COMP. BITS
7 DIGITAL GROUND 34 OUTPUT ENABLE
8 FIFO/DIR 33 OVERFLOW

9 FIFO READ 32 EOC
10 FSTAT1 31 +5V DIGITAL SUPPLY
11 FSTAT2 30 DIGITAL GROUND
12 START CONVERT 29 BIT 1 (MSB)
13 BIT 16 (LSB) 28 BIT 1 (MSB)
14 BIT 15 27 BIT 2
15 BIT 14 26 BIT 3
16 BIT 13 25 BIT 4
17 BIT 12 24 BIT 5
18 BIT 11 23 BIT 6
19 BIT 10 22 BIT 7
20 BIT 9 21 BIT 8

FEATURES

• 16-bit resolution

• 3MHz sampling rate

• Functionally complete

• No missing codes over full military temperature range

• Edge-triggered

• ±5V supplies, 1.85 Watts

• Small, 40-pin, ceramic TDIP

• 85dB SNR, –84dB THD

• Ideal for both time and frequency-domain applications

16-Bit, 3MHz

Sampling A/D Converters

®

®

INNOV A TION and EX CELLENCE

GENERAL DESCRIPTION

The low-cost ADS-933 is a 16-bit, 3MHz sampling A/D
converter. This device accurately samples full-scale input
signals up to Nyquist frequencies with no missing codes. The
dynamic performance of the ADS-933 has been optimized to
achieve a signal-to-noise ratio (SNR) of 85dB and a total
harmonic distortion (THD) of –84dB.

Packaged in a 40-pin TDIP, the functionally complete
ADS-933 contains a fast-settling sample-hold amplifier, a
subranging (two-pass) A/D converter, an internal reference,
timing/control logic, and error-correction circuitry. Digital input
and output levels are TTL. The ADS-933 only requires the
rising edge of the start convert pulse to operate.

Requiring only ±5V supplies, the ADS-933 dissipates 1.85
Watts. The device is offered with a bipolar (±2.75V) analog
input range and a unipolar 0 to –5.5V input range. Models are
available for use in either commercial (0 to +70°C) or military (–
55 to +125°C) operating temperature ranges. A proprietary, auto­calibrating, error-correcting circuit enables the device to achieve
specified performance over the full military temperature range.
Typical applications include medical imaging, radar, sonar,
communications and instrumentation.

INPUT/OUTPUT CONNECTIONS

ADS-933

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

Figure 1. ADS-933 Functional Block Diagram

PRELIMINARY PRODUCT DATA

3-STATE

OUTPUT REGISTER

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

TIMING AND

CONTROL LOGIC

GAIN ADJUST 6

+3.2V REF. OUT 1

OFFSET ADJUST 5

EOC 32

+5V ANALOG SUPPLY 38
+5V DIGITAL SUPPLY 31
–5V SUPPLY 37
ANALOG GROUND 4, 36
DIGITAL GROUND 7, 30
NO CONNECTION 39, 40

CUSTOM GATE ARRAY

POWER AND GROUNDING

2-PASS ANALOG-TO-DIGITAL CONVERTER

S/H

GAIN

ADJUST

CKT.

OFFSET
ADJUST

CKT.

PRECISION

+3.2V REFERENCE

ANALOG INPUT 3

START CONVERT 12

COMP. BITS 35

10 FSTAT1
11 FSTAT2

8 FIFO/DIR
9 FIFO/READ

34 OUTPUT ENABLE

33 OVERFLOW

UNIPOLAR 2

OFFSET ADJUST 5

ADS-933

® ®

2

PARAMETERS MIN. TYP. MAX. UNITS

Operating Temp. Range, Case

ADS-933MC 0 — +70 °C
ADS-933MM –55 — +125 °C

Thermal Impedance

θjc — 4 — °C/Watt
θca — 18 — °C/Watt

Storage Temperature Range –65 — +150 °C
Package Type 40-pin, metal-sealed, ceramic TDIP

Weight 0.56 ounces (16 grams)

ABSOLUTE MAXIMUM RATINGS

PARAMETERS LIMITS UNITS

+5V Supply (Pins 31, 38) 0 to +6 Volts
–5V Supply (Pin 37) 0 to –6 Volts
Digital Inputs (Pins 8, 9, 12, 34, 35) –0.3 to +V

DD +0.3 Volts

Analog Input (Pin 3) ±5 Volts
Lead Temperature (10 seconds) +300 °C

PHYSICAL/ENVIRONMENTAL

FUNCTIONAL SPECIFICATIONS

(TA = +25°C, ±VCC = ±5V, +VDD = +5V, 3MHz sampling rate, and a minimum 3 minute warm-up ➀ unless otherwise specified.)

+25°C 0 to +70°C –55 to +125°C

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

Input Voltage Range

Unipolar — 0 to –5.5 — — 0 to –5.5 — — 0 to –5.5 — Volts
Bipolar — ±2.75 — — ±2.75 — — ±2.75 — Volts

Input Resistance Pin 3 655 687 — 655 687 — 655 687 — Ω
Input ResistancePin 2 418 426 — 418 426 — 418 426 — Ω
Input Capacitance — 10 15 — 10 15 — 10 15 pF

DIGITAL INPUTS

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" ➁ — — –20 — — –20 — — –20 µA

Start Convert Positive Pulse Width ➂ 20 50 — 20 50 — 20 50 — ns

STATIC PERFORMANCE

Resolution — 16 — — 16 — — 16 — Bits
Integral Nonlinearity (f

in = 10kHz) — ±1 — — ±1.5 — — ±2 — LSB

Differential Nonlinearity (f

in = 10kHz) –0.95 ±0.5 +1.0 –0.95 ±0.5 +1.0 –0.95 ±0.5 +1.5 LSB

Full Scale Absolute Accuracy — ±0.15 ±0.3 — ±0.3 ±0.5 — ±0.5 ±0.8 %FSR
Bipolar Zero Error (Tech Note 2) — ±0.1 ±0.2 — ±0.2 ±0.4 — ±0.4 ±0.6 %FSR

(Unipolar offset spec same as Bipolar zero)

Bipolar Offset Error (Tech Note 2) — ±0.1 ±0.2 — ±0.2 ±0.4 — ±0.4 ±0.6 %FSR
Gain Error (Tech Note 2) — ±0.15 ±0.3 — ±0.3 ±0.5 — ±0.5 ±0.8 %
No Missing Codes (f

in = 10kHz) 16 — — 16 — — 16 — — Bits

DYNAMIC PERFORMANCE

Peak Harmonics (–0.5dB)

dc to 500kHz — — 81 — –86 — — –86 — dB
500kHz to 1MHz — –84 80 — –84 — — –84 — dB

Total Harmonic Distortion (–0.5dB)

dc to 500kHz — –84 80 — –84 — — –84 — dB
500kHz to 1MHz — –83 80 — –83 — — –83 — dB

Signal-to-Noise Ratio

(w/o distortion, –0.5dB)
dc to 500kHz 81 85 — — 85 — — 85 — dB
500kHz to 1MHz 81 85 — — 85 — — 85 — dB

Signal-to-Noise Ratio ➃

(& distortion, –0.5dB)
dc to 500kHz 78 82 — — 82 — — 82 — dB
500kHz to 1MHz 78 81 — — 81 — — 81 — dB

Noise — 80 — — 80 — — 80 — µVrms
Two-Tone Intermodulation

Distortion (f

in = 200kHz,

240kHz, f

s = 3MHz, –0.5dB) — –87 — — –87 — — –87 — dB

Input Bandwidth (–3dB)

Small Signal (–20dB input) — 9.8 — — 9.8 — — 9.8 — MHz
Large Signal (–0.5dB input) — 10.2 — — 10.2 — — 10.2 — MHz

Feedthrough Rejection

(f

in = 1MHz) — 90 — — 90 — — 90 — dB

Slew Rate — ±120 — — ±120 — — ±120 — V/µs
Aperture Delay Time — +8 — — +8 — — +8 — ns
Aperture Uncertainty — 3 — — 3 — — 3 — psrms
S/H Acquisition Time

( to ±0.001%FSR, 5.5V step) — 180 — — 180 — — 180 — ns

ADS-933

® ®

3

+25°C 0 TO +70°C –55 TO +125°C

DYNAMIC PERFORMANCE (Cont.) MIN. TYP. MAX. MIN. TYP. MAX. MIN. TYP. MAX. UNITS
ANALOG OUTPUT

Overvoltage Recovery Time ➄ — — 333 — — 333 — — 333 ns
A/D Conversion Rate 3 — — 3 — — 3 — — MHz
Internal Reference

Voltage 3.15 +3.2 — — +3.2 — — +3.2 — Volts
Drift — ±30 — — ±30 — — ±30 — ppm/°C

External Current — 5 — — 5 — — 5 — mA

DIGITAL OUTPUTS

Logic Levels

Logic "1" +2.4 — — +2.4 — — +2.4 — — Volts
Logic "0" — — +0.4 — — +0.4 — — +0.4 Volts
Logic Loading "1" — — –4 — — –4 — — –4 mA
Logic Loading "0" — — +4 — — +4 — — +4 mA

Output Coding

Offset Binary / Complementary Offset Binary / Two's Complement / Complementary Two's Complement

POWER REQUIREMENTS

Power Supply Ranges ⑥

+5V Supply +4.75 +5.0 +5.25 +4.75 +5.0 +5.25 +4.9 +5.0 +5.25 Volts
–5V Supply –4.75 –5.0 –5.25 –4.75 –5.0 –5.25 –4.9 –5.0 –5.25 Volts

Power Supply Currents

+5V Supply — +220 260 — +220 260 — +220 260 mA
–5V Supply –140 –150 — –140 –150 — –140 –150 — mA

Power Dissipation — 1.85 2.0 — 1.85 2.0 — 1.85 2.0 Watts
Power Supply Rejection — — ±0.07 — — ±0.07 — — ±0.07 %FSR/%V

Footnotes:

➃ Effective bits is equal to:

➀ All power supplies must be on before applying a start convert pulse. All

supplies and the clock (START CONVERT) must be present during
warm-up periods. The device must be continuously converting during
this time.

➁ When COMP. BITS (pin 35) is low, logic loading "0" will be –350µA.
➂ A 3MHz clock with a 50nsec positive pulse width is used for all

production testing. See Timing Diagram for more details.

6.02

(SNR + Distortion) – 1.76 + 20 log

Full Scale Amplitude

Actual Input Amplitude

➄ This is the time required before the A/D output data is valid once the

analog input is back within the specified range.

➅ The minimum supply voltages of +4.9V and –4.9V for ±V

DD are required for

–55°C operation only. The minimum limits are +4.75V and –4.75V when
operating at +125°C.

TECHNICAL NOTES

1. Obtaining fully specified performance from the ADS-933
requires careful attention to pc-card layout and power
supply decoupling. The device's analog and digital ground
systems are connected to each other internally. For optimal
performance, tie all ground pins (2, 4, 7, 30 and 36) directly
to a large analog ground plane beneath the package.

Bypass all power supplies and the +3.2V reference output
to ground with 4.7µF tantalum capacitors in parallel with

0.1µF ceramic capacitors. Locate the bypass capacitors as
close to the unit as possible.

2. The ADS-933 achieves its specified accuracies without the
need for external calibration. If required, the device's small
initial offset and gain errors can be reduced to zero using
the adjustment circuitry shown in Figure 2. When using this
circuitry, or any similar offset and gain calibration hardware,
make adjustments following warm-up. To avoid interaction,
always adjust offset before gain. Tie pins 5 and 6 to
ANALOG GROUND (pin 4) if not using offset and gain
adjust circuits.

3. Pin 35 (COMP. BITS) is used to select the digital output
coding format of the ADS-933. See Tables 2a and 2b.
When this pin has a TTL logic "0" applied, it complements
all of the ADS-933’s digital outputs.

When pin 35 has a logic "1" applied, the output coding is
complementary offset binary. Applying a logic "0" to pin
35 changes the coding to offset binary. Using the MSB
output (pin 29) instead of the MSB output (pin 28) changes
the respective output codings to complementary two's
complement and two's complement.

Pin 35 is TTL compatible and can be directly driven with
digital logic in applications requiring dynamic control over
its function. There is an internal pull-up resistor on pin 35
allowing it to be either connected to +5V or left open when
a logic "1" is required.

4. To enable the three-state outputs, connect OUTPUT
ENABLE (pin 34) to a logic "0" (low). To disable, connect
pin 34 to a logic "1" (high).