DATEL ADS-926-883, ADS-916MM, ADS-916MC, ADS-916GM, ADS-916GC Datasheet

® ®

ADS-916

14-Bit, 500kHz, Low-Power

Sampling A/D Converters

Figure 1. ADS-916 Functional Block Diagram

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

FEATURES

• 14-bit resolution

• 500kHz sampling rate

• Functionally complete; No missing codes

• Edge-triggered; No pipeline delays

• Small 24-pin DDIP or SMT package

• Low power, 1.8 Watts maximum

• Operates from ±15V or ±12V supplies

• Unipolar 0 to +10V input range

GENERAL DESCRIPTION

The ADS-916 is a high-performance, 14-bit, 500kHz sampling
A/D converter. This device samples input signals up to Nyquist
frequencies with no missing codes. The ADS-916 features
outstanding dynamic performance including a THD of –90dB.

Housed in a small 24-pin DDIP or SMT (gull-wing) package,
the functionally complete ADS-916 contains a fast-settling
sample-hold amplifier, a subranging (two-pass) A/D converter,
a precise voltage reference, timing/control logic, and error­correction circuitry. Digital input and output levels are TTL.

Requiring ±15V (or ±12V) and +5V supplies, the ADS-916
dissipates 1.8W (1.6W for ±12V) maximum. The unit is offered
with a unipolar input (0 to +10V). Models are available for use
in either commercial (0 to +70°C) or military (–55 to +125°C)
operating temperature ranges. Applications include radar,
sonar, spectrum analysis, and graphic/medical imaging.

INPUT/OUTPUT CONNECTIONS

PIN FUNCTION PIN FUNCTION

1 BIT 14 (LSB) 24 –12V/–15V SUPPLY
2 BIT 13 23 ANALOG GROUND
3 BIT 12 22 +12V/+15V SUPPLY
4 BIT 11 21 +10V REFERENCE OUT
5 BIT 10 20 ANALOG INPUT
6 BIT 9 19 ANALOG GROUND
7 BIT 8 18 BIT 1 (MSB)
8 BIT 7 17 BIT 2

9 BIT 6 16 START CONVERT
10 BIT 5 15 EOC
11 BIT 4 14 DIGITAL GROUND
12 BIT 3 13 +5V SUPPLY

REF

REGISTER

REGISTER

18 BIT 1 (MSB)
17 BIT 2
12 BIT 3
11 BIT 4
10 BIT 5
9 BIT 6
8 BIT 7
7 BIT 8
6 BIT 9
5 BIT 10
4 BIT 11
3 BIT 12
2 BIT 13

1 BIT 14 (LSB)

TIMING AND

CONTROL LOGIC

+10V REF. OUT 21

START CONVERT 16

EOC 15

DIGITAL CORRECTION LOGIC

DAC

FLASH

ADC

BUFFER

–
+

S/H

ANALOG INPUT 20

13

+5V SUPPLY

22

+12V/+15V SUPPLY

19, 23

ANALOG GROUND

14

DIGITAL GROUND

24

–12V/–15V SUPPLY

S

2

S1

® ®

ADS-916

2

ABSOLUTE MAXIMUM RATINGS

PARAMETERS LIMITS UNITS

+12V/+15V Supply (Pin 22) 0 to +16 Volts
–12V/–15V Supply (Pin 24) 0 to –16 Volts
+5V Supply (Pin 13) 0 to +6 Volts
Digital Input (Pin 16) –0.3 to +V

DD +0.3 Volts

Analog Input (Pin 20) –4 to +17 Volts
Lead Temperature (10 seconds) +300 °C

PHYSICAL/ENVIRONMENTAL

PARAMETERS MIN. TYP. MAX. UNITS

Operating Temp. Range, Case

ADS-916MC, GC 0 — +70 °C
ADS-916MM, GM –55 — +125 °C

Thermal Impedance

θjc 6 °C/Watt
θca 24 °C/Watt

Storage Temperature –65 — +150 °C
Package Type 24-pin, metal-sealed, ceramic DDIP or SMT
Weight 0.42 ounces (12 grams)

+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 ➁ — 0 to +10 — — 0 to +10 — — 0 to +10 — Volts
Input Resistance — 1 — — 1 — — 1 — kΩ
Input Capacitance — 7 15 — 7 15 — 7 15 pF

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 50 200 — 50 200 — 50 200 — ns

STATIC PERFORMANCE

Resolution — 14 — — 14 — — 14 — Bits
Integral Nonlinearity (f

in = 10kHz) — ±0.5 — — ±0.75 — — ±1.5 — LSB

Differential Nonlinearity (f

in = 10kHz) — ±0.5 ±0.95 — ±0.5 ±0.95 –0.95 ±0.75 +1.25 LSB

Full Scale Absolute Accuracy — ±0.05 ±0.1 — ±0.1 ±0.2 — ±0.15 ±0.4 %FSR
Unipolar Offset Error (Tech Note 2) — ±0.1 ±0.2 — ±0.1 ±0.2 — ±0.15 ±0.4 %FSR
Gain Error (Tech Note 2) — ±0.1 ±0.25 — ±0.1 ±0.25 — ±0.25 ±0.4 %
No Missing Codes (f

in = 10kHz) 14 — — 14 — — 14 — — Bits

DYNAMIC PERFORMANCE

Peak Harmonics (–0.5dB)

dc to 100kHz — –91 –86 — –91 –86 — –90 –82 dB
100kHz to 250kHz — –84 –79 — –84 –79 — –82 –76 dB

Total Harmonic Distortion (–0.5dB)

dc to 100kHz — –90 –85 — –90 –85 — –87 –81 dB
100kHz to 250kHz — –82 –77 — –82 –77 — –80 –74 dB

Signal-to-Noise Ratio

(w/o distortion, –0.5dB)
dc to 100kHz 77 81 — 77 81 — 76 80 — dB
100kHz to 250kHz 75 80 — 75 80 — 74 78 — dB

Signal-to-Noise Ratio ➃

(& distortion, –0.5dB)
dc to 100kHz 77 80 — 77 80 — 75 78 — dB
100kHz to 250kHz 72 78 — 72 78 — 70 76 — dB

Two-Tone Intermodulation

Distortion (f

in = 100kHz,

240kHz, f

s = 500kHz –0.5dB) — –86 — — –86 — — –86 — dB

Noise — 310 — — 310 — — 360 — µVrms
Input Bandwidth (–3dB)

Small Signal (–20dB input) — 7 — — 7 — — 7 — MHz
Large Signal (–0.5dB input) — 3 — — 3 — — 3 — MHz

Feedthrough Rejection (f

in = 250kHz) — 84 — — 84 — — 84 — dB

Slew Rate — ±40 — — ±40 — — ±40 — 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) 1530 1570 1610 1530 1570 1610 1530 1570 1610 ns

Overvoltage Recovery Time ➄ — 1400 2000 — 1400 2000 — 1400 2000 ns
A/D Conversion Rate 500 — — 500 — — 500 — — kHz

FUNCTIONAL SPECIFICATIONS

(TA = +25°C, ±VCC = ±15V (or ±12V), +VDD = +5V, 500kHz sampling rate, and a minimum 1 minute warmup ➀ unless otherwise specified.)

® ®

ADS-916

3

+25°C 0 to +70°C –55 to +125°C

ANALOG OUTPUT MIN. TYP. MAX. MIN. TYP. MAX. MIN. TYP. MAX. UNITS

Internal Reference

Voltage +9.95 +10.0 +10.05 +9.95 +10.0 +10.05 +9.95 +10.0 +10.05 Volts
Drift — ±5 — — ±5 — — ±5 — ppm/°C

External Current — — 1.5 — — 1.5 — — 1.5 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

Delay, Falling Edge of EOC

to Output Data Valid — — 35 — — 35 — — 35 ns

Output Coding

Straight Binary

POWER REQUIREMENTS, ±15V

Power Supply Ranges

+15V Supply +14.5 +15.0 +15.5 +14.5 +15.0 +15.5 +14.5 +15.0 +15.5 Volts
–15V Supply –14.5 –15.0 –15.5 –14.5 –15.0 –15.5 –14.5 –15.0 –15.5 Volts
+5V Supply +4.75 +5.0 +5.25 +4.75 +5.0 +5.25 +4.75 +5.0 +5.25 Volts

Power Supply Currents

+15V Supply — +50 +65 — +50 +65 — +50 +65 mA
–15V Supply — –40 –50 — –40 –50 — –40 –50 mA
+5V Supply — +70 +85 — +70 +85 — +70 +85 mA

Power Dissipation — 1.6 1.8 — 1.6 1.8 — 1.6 1.8 Watts
Power Supply Rejection — — ±0.01 — — ±0.01 — — ±0.01 %FSR/%V

POWER REQUIREMENTS, ±12V

Power Supply Ranges

+12V Supply +11.5 +12.0 +12.5 +11.5 +12.0 +12.5 +11.5 +12.0 +12.5 Volts
–12V Supply –11.5 –12.0 –12.5 –11.5 –12.0 –12.5 –11.5 –12.0 –12.5 Volts
+5V Supply +4.75 +5.0 +5.25 +4.75 +5.0 +5.25 +4.75 +5.0 +5.25 Volts

Power Supply Currents

+12V Supply — +50 +65 — +50 +65 — +50 +65 mA
–12V Supply — –40 –50 — –40 –50 — –40 –50 mA
+5V Supply — +70 +80 — +70 +80 — +70 +80 mA

Power Dissipation — 1.4 1.6 — 1.4 1.6 — 1.4 1.6 Watts
Power Supply Rejection — — ±0.01 — — ±0.01 — — ±0.01 %FSR/%V

6.02

(SNR + Distortion) – 1.76 + 20 log

Full Scale Amplitude

Actual Input Amplitude

➃ Effective bits is equal to:

➄ This is the time required before the A/D output data is valid after the analog input

is back within the specified range.

Footnotes:

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

and the clock (START CONVERT) must be present during warmup periods. The
device must be continuously converting during this time. There is a slight
degradation in performance when using ±12V supplies.

➁ See Ordering Information for availability of ±5V input range. Contact DATEL for

availability of other input voltage ranges.

➂ A 500 kHz clock with a 200ns wide start convert pulse is used for all production

testing. Only the rising edge of the start convert pulse is required for the device
to operate (edge-triggered). See Timing Diagram for more details.

TECHNICAL NOTES

1. Obtaining fully specified performance from the ADS-916
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 (14, 19 and 23) directly to a
large analog ground plane beneath the package.

Bypass all power supplies and the REFERENCE OUTPUT
(pin 21) 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. If the user-installed
offset and gain adjusting circuit shown in Figure 2 is used,
also locate it as close to the ADS-916 as possible.

2. The ADS-916 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 input circuit of Figure 2. When using this circuit, or any
similar offset and gain-calibration hardware, make adjust­ments following warmup. To avoid interaction, always adjust
offset before gain.

3. When operating the ADS-916 from ±12V supplies, do not
drive external circuitry with the REFERENCE OUTPUT. The
reference's accuracy and drift specifications may not be
met, and loading the circuit may cause accuracy errors
within the converter.

4. Applying a start convert pulse while a conversion is in
progress (EOC = logic "1") initiates a new and inaccurate
conversion cycle. Data for the interrupted and subsequent
conversions will be invalid.