Introduction

The ADC4320, ADC4322, and ADC4325 are complete 16-bit, 1 MHz, 2
MHz, and 500 kHz A/D converter subsystems with a built-in sample-and-
hold amplifier in a space-saving 46-pin hybrid package. They offer pin-
programmable input voltage ranges of ±2.5V, ±5V, ±10V and 0 to +10V,
and have been designed for use in applications, such as ATE, digital os-
cilloscopes, medical imaging, radar, sonar, and analytical instrumenta-
tion, requiring high speed and high resolution front ends. The ADC4322
is capable of digitizing a 1 MHz signal at a 2 MHz sampling rate with a
guarantee of no missing codes from 0°C to +70°C, or in an extended
temperature range version, from 25°C to +85°C. Equally impressive in
frequency domain applications, the ADC4325 features 91 dB minimum
signal-to-noise ratio with input signals from DC to 100 kHz.

The ADC432X Series utilizes the latest semiconductor technologies to
produce a cost-effective, high performance part in a 46-pin hybrid pack-
age. They are designed around a two-pass, sub-ranging architecture that
integrates a low distortion sample-and-hold amplifier, precision voltage
reference, ultra-stable 16-bit linear reference D/A converter, all necessary
timing circuitry, and tri-state CMOS/TTL compatible output lines for ease
of system integration.

Superior performance and ease-of-use make the ADC432X Series the
ideal solution for those applications requiring a sample-and-hold amplifier
directly at the input to the A/D converter. Having the S/H amplifier inte-
grated with the A/D converter benefits the system designer in two ways.
First, the S/H has been designed specifically to complement the perfor-
mance of the A/D converter; for example, the acquisition time, hold mode
settling and droop rate have been optimized for the A/D converter, result-
ing in exceptional overall performance. Second, the designer achieves

Features

2 MHz, 1 MHz, and 500 kHz
Conversion Rates

16-Bit Resolution

0.003% Maximum Integral
Nonlinearity

No Missing Codes

Peak Distortion: 92 dB Max.
(100 kHz Input)

Signal to Noise Ratio:

86 dB (ADC4322) Min.
89 dB (ADC4320) Min.
91 dB (ADC4325) Min.

Total Harmonic Distortion:

(100 kHz Input)
86 dB (ADC4320) Max.
90 dB (ADC4325) Max.

TTL/CMOS Compatibility

Low Noise

Electromagnetic/Electrostatic
Shielding

Applications

Digital Signal Processing

Sampling Oscilloscopes

Automatic Test Equipment

High-Resolution Imaging

Analytical Instrumentation

Medical Instrumentation

CCD Detectors

IR Imaging

Sonar/Radar

Figure 1. Functional Block Diagram.

Very High Speed 16-Bit,

Sampling A/D Converters

in a Space-Saving 46-Pin Hybrid Package

ADC4320/ADC4322/

ADC4325

S/H IN 3

S/H IN 1

S/H IN 2

DNC

S/H

6.4

EXT OFF ADJ

0.2

10-Bit

Flash ADC

9-Bit
Data

Trigger

Transfer

Hi Byte EN

Lo Byte EN

O/U Flow

B1-B16

Gate

Array

Timing

Circuit

Pass1/Pass2

9-Bit DAC

16-Bit Linear

MUX Amp

Residue Amp

9-Bit Data

+REF OUT

REF OUT

Ext Gain Adj

Reference

ADC Clk

S/H Control

Continued on page 5.

ADC4320/ADC4322/

ADC4325

Specifications

SPECIFICATION

ADC4325

ADC4320

ADC4322

ANALOG INPUT

Input Voltage Range
Bipolar

±2.5V, ±5V, ±10V

Unipolar

0 to +10V

Max. Input Without Damage

±15.5V ±15.5V ±15.5V

Input Impedance
±2.5V

750

±5.0V, 0-10V

1.5 K

±10V

3 k

Offset/Gain Adj. Sensitivity

300 ppm FSR/V

DIGITAL INPUTS

Compatibility

TTL, HCT, and ACT

Logic "0"

+0.8V Max.

Logic "1"

+2.0V Min.

Trigger

Negative Edge Triggered

Loading

2 HCT Loads

TriggerPulse Width

100 ns Min.

50 ns Min.

High Byte Enable

Active Low, B1-B8, B1

Low Byte Enable

Active Low, B9-B16

DIGITAL OUTPUTS

Fan-Out

1 TTL Load

Logic "0"

+0.4V

Logic "1"

+2.4V

Output Coding

Binary, Offset Binary,

Two's Complement

Transfer Pulse

Data valid on positive edge

Over/Under Flow

Valid = logic "0" (occurs only

when ±FS have been exc'd.)

when ±FS have been exc'd)

DYNAMIC
CHARACTERISTICS

Maximum Throughput Rate

500 kHz

1.0 MHz

2.0 MHz

A/D Conversion Time

1.1 µs Typ.

620 ns Typ.

300 ns Typ.

S/H Acquisition Time

900 ns Typ.

380 ns Typ.

200 ns Typ.

S/H Aperture Delay

15 ns Max.

S/H Aperture Jitter

5 ps RMS Max.

S/H Feedthrough

90 dB Max.; 96 dB Typ.

Full Power Bandwidth

2.6 MHz Min.

3 MHz Min.

6 MHz Min.

Small Signal Bandwidth

2.6 MHz Min.

6 MHz Min.

8 MHz Min.

Signal to Noise Ratio

100 kHz Input @ 0 dB

91 dB Min.;93 dB Typ.

89 dB Min.; 92 dB Typ.

86 dB Min.; 88 dB Typ.

495 kHz Input @ 10 dB

79 dB Min.; 82 dB Typ.

76 dB Min.; 78 dB Typ.

980 kHz Input @ 10 dB

75 dB Min.; 78 dB Typ.

Peak Distortion

100 kHz Input @ 0 dB

92 dB Max.; 97 dB Typ.

495 kHz Input @ 10 dB

84 dB Max.; 95 dB Typ.

980 kHz Input @ 10 dB

81 dB Max.; 88 dB Typ.

Total Harmonic Distortion

100 kHz Input @ 0 dB

90 dB Max.; 95 dB Typ.

86 dB Max.; 94 dB Typ.

86 dB Max. 94 dB Typ.

495 kHz Input @ 10 dB

79 dB Max.; 86 dB Typ.

80 dB Max.; 88 dB Typ.

980 kHz Input @ 10 dB

80 dB Max.; 85 dB Typ.

THD + Noise

100 kHz Input @ 0 dB

88 dB Min.; 91 dB Typ.

84 dB Min.; 91 dB Typ.

83 dB Min.; 87 dB Typ.

495 kHz Input @ 10 dB

76 dB Min.; 81 dB Typ.

75 dB Min.; 77 dB Typ.

980 kHz Input @ 10 dB

74 dB Min.; 77dB Typ.

SPECIFICATION (CONT.)

ADC4325

ADC4320

ADC4322

Step Response

800 ns Max. to 1 LSB

500 ns Max. to 1 LSB

250 ns Max. to 2 LSBs

INTERNAL REFERENCE

Voltage

+5V, ±0.5% Max.

Stability

15 ppm/°C Max.

Available Current

1.0 mA Max.

TRANSFER CHARACTERISTICS

Resolution

16 bits

Integral Nonlinearity

±0.003% FSR Max.; ±0.001% Typ. ±0.003% FSR Max.; ±0.001% Typ. ±0.003% FSR Max.; ±0.001% Typ

Differential Nonlinearity

±0.75 LSB; ±0.5 LSB Typ.

±0.75 LSB Max.; ±0.5 LSB Typ.

Monotonicity

Guaranteed

No Missing Codes

Guaranteed over the Specified

Temperature Range

Offset Error

±0.1% FSR Max. (Adj. to Zero)

Gain Error

±0.1% FSR Max. (Adj. to Zero)

Noise

10V p-p FSR

55 µV RMS Typ.; 70 µV RMS Max.

65 µV RMS Typ.; 80 µV RMS Max. 90 µV RMS Typ.; 110 µV Max.

5V p-p FSR

45 µV RMS Typ.; 55 µV RMS Max.

50 µV RMS Typ.; 60 µV RMS Max. 65 µV RMS Typ., 80 µV Max.

STABILITY
Differential Nonlinearity TC ±1 PPM/°C MAX.

±1 PPM/°C MAX

.±1 PPM/°C MAX.

Offset TC

±15 ppm/°C Max.

Gain TC

±15 ppm/°C Max.

Warm-Up Time

5 Min. Max.

Supply Rejection per % change in
any supply Offset & Gain

±10 ppm/% Max.

POWER REQUIREMENTS

±15V Supplies

14.55V Min., 15.45V Max.

+5V Supplies

+4.75V Min., +5.25V Max.

+15V Current Drain

63 mA Typ.

71 mA Typ.

15V Current Drain

54 mA Typ.

61 mA Typ.

+5V Current Drain

67 mA Typ.

Total Power Consumption

2.1W Typ.

2.3W Typ.

ENVIRONMENTAL & MECHANICAL

Specified Temp. Range

A Version

0°C to +70°C

B Version

25°C to +85°C

Storage Temp. Range

25°C to 125°C

Dimensions

1.58" x 2.38" x 0.225"

(40.13 mm x 60.45 mm x 5.7 mm)

Case Potential

Ground

NOTES:

1. All specifications guaranteed at 25°C unless otherwise

noted and supplies at ±15V and +5V.

2. All dynamic characteristics measured on the ±5V input

range except the 980 kHz distortion test are performed at
the ±2.5V input range.

3. Measured with a full scale step input.

4. See performance testing.

5. THD + noise represents the ratio of the RMS value of the

signal to the total RMS noise below the Nyquist plus the
total harmonic distortion up to the 100th harmonic with an
analysis bandwidth of DC to the converters' Nyquist fre-
quency.

6. Step response represents the time required to achieve the

specified accuracies after an input full scale step change.

7. Reference Load to remain stable.

8. Includes noise from S/H and A/D converter.

9. Both ±15V analog supply voltages and both ±reference

voltages, Pins 2, 3, 16, and 17 must be by-passed with low
ESR tantalum capacitors (see Figure 20).

10. The specified temperature range is guaranteed for the

case temperature.

Specifications subject to change without notice.

SPECIFICATIONS

true 16-bit performance, avoiding degradation due to
ground loops, signal coupling, jitter and digital noise in-
troduced when separate S/H and A/D converters are in-
terconnected. Furthermore, the accuracy, speed, and
quality of the ADC432X Series are fully ensured by thor-
ough, computer-controlled factory tests of each unit.

INTERFACING

Input Scaling

The converters can be configured for four input voltage
ranges: 0 to +10V; ±2.5V; ±5V; and ±10V. The analog
input range should be scaled as close as possible to the
maximum input to utilize the full dynamic range of the
converter. Figure 13 describes the input connections.

Coding and Trim Procedure

Figure 15 shows the output coding and trim calibration
voltages of the converter. For two's complement opera-
tion, simply use the available B1 (MSB) instead of B1
(MSB). Refer to Figure 14 for use of external offset and
gain trim potentiometers. Voltage DACs with a ±5V out-
put can be utilized easily when digital control is required.
The input sensitivity of the external offset and gain con-
trol pins is 300 ppm FSR/V. If Offset and Gain adjusts
are not used, connect them to Pin 14, Analog Returns.

To trim the offset of the converter, apply the offset volt-
age shown in Figure 15 for the appropriate voltage
range. Adjust the offset trim potentiometer such that
the 15 MSBs are "0" and the LSB alternates equally
between "0" and "1" for the unipolar ranges or all 16
bits are in transition for the bipolar ranges.

To trim the gain of the converter, apply the range (+FS)
voltage shown in Figure 15 for the appropriate range.
Adjust the gain trim potentiometer such that the 15
MSBs are "1" and the LSB alternates equally between
"0" and "1".

Figure 10. ADC4322 SFDR vs Input Level @
195 kHz ±2.5V Range

Figure 11. ADC4322 SFDR vs Input Level @
495 kHz ±2.5V Range

Figure 12. ADC4322 SFDR vs Input Level @
980 kHz ±2.5V Range

PIN # 4

5 6

RANGE

S/H IN 1

S/H IN2

S/H IN 3

0V to +10V

Input

5V Ref

±5V

Input

SIG RTN

±2.5V

Input

±10V

Input

SIG RTN

Figure 13. Input Scaling Connections.

Continued from page 1.

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