DATEL ADS-EVAL4, ADS-941ME, ADS-941MC Datasheet

® ®

REGISTERREGISTER

START CONVERT 32

DIGITAL CORRECTION LOGIC

GROUND

GROUND

SUPPLY

3-STATE OUTPUT REGISTER

SUPPLY

GROUND

SELECT

SUPPLY

FEATURES

• 14-bit resolution

• 1MHz minimum sampling rate

• Functionally complete

• Internal reference and sample/hold

• No missing codes

• Excellent performance

• Full Nyquist-rate sampling

• Small 32–pin DIP

• Low power, 2.8 Watts

ADS-941

14-Bit, 1MHz

Sampling A/D Converters

GENERAL DESCRIPTION

DATEL's ADS-941 is a functionally complete, 14-bit, 1MHz,
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, a three-state output register, and all the timing and
control logic necessary to operate from a single start convert
pulse.

The ADS-941 is optimized for wideband frequency-domain
applications and is fully FFT tested. Total harmonic distortion
(THD) and signal-to-noise ratio (including distortion) typically
run at –85dB and 80dB, respectively, with full-scale inputs up
to 100kHz.

The ADS-941 requires ±15V and +5V supplies and typically
consumes 2.8 Watts.

+10V REF. OUT 1

OFFSET ADJUST 5

BIPOLAR 2

ANALOG INPUT 3

S/H

OFFSET
CIRCUIT

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)

EOC 16

TIMING AND

CONTROL LOGIC

4

SIGNAL

10

+5V

11

DIGITAL

12

+15V

6, 14, 15
ANALOG

13

–5V

8

CODING

9 ENABLE
7 OVERFLOW

Figure 1. ADS-941 Functional Block Diagram

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

ADS-941

® ®

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 +6.0 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, 1MHz 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 2.2 2.5 — kΩ
Input Capacitance — 7 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

Integral Non-Linearity

in = 10KHz)

(f

+25°C — ±1 ±2 LSB
0 to +70°C — ±1.5 ±2 LSB
–40 to +85°C — ±2 ±3 LSB

Differential Non-Linearity

in = 10KHz)

(f

+25°C –0.75 ±0.5 ±0.75 LSB
0 to +70°C –0.95 ±0.75 ±0.95 LSB
–40 to +85°C –1 ±0.95 +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 ±0.12 %FSR
0 to +70°C — ±0.12 ±0.3 %FSR
–40 to +85°C — ±0.6 ±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

Resolution 14 Bits

in = 500kHz)

OUTPUTS MIN. TYP. MAX. UNITS

Output Coding Staight Bin./Offset Bin./Two'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

Slew Rate — ±250 1 V/µs
Aperature Delay Time — — 10 ns
Aperature Uncertainty — — ±5 ps
S/H Aquisition TIme

(to ±0.003%FS, 10V step) — 250 350 ns

Total Harm. Distort. (–0.5dB)

dc to 100kHz –78 –85 — dB
100kHz to 500kHz –77 –80 — dB

Signal-to-Noise Ratio

(w/o distortion, –0.5dB
dc to 100kHz 75 80 — dB
100kHz to 500kHz 74 77 — dB

Signal-to-Noise Ratio

(and distortion, –0.5dB)
dc to 100kHz 74 80 — dB
100kHz to 500kHz 73 78 — dB

Spurious Free Dyn. Range ➀

dc to 100kHz78 78 86 — dB
100 to 500kHz 77 83 — 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 (–0dB input) — 1.75 — MHz

Feedthrough Rejection

in = 500KHz) — 87 — dB

(f

Overvoltage Recovery, ±12V — 1000 2000 ns
A/D Conversion Rate 1 — — MHz
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 — +62 +85 mA
–15V Supply — –80 –95 mA
+5V Supply — +140 +160 mA

Power Dissipation — 2.8 3.3 Watts
Power Supply Rejection — — ±0.02 %FSR%V

PHYSICAL/ENVIRONMENTAL

Operating Temp. Range, Case

ADS-941MC 0 — +70 °C
ADS-941ME –40 — +85 °C

Storage Temperature Range –65 — +150 °C
Package Type 32-pin, metal-sealed, ceramic TDIP
Weight 0.46 ounces (13 grams)

Footnote:

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

2